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https://www.usgs.gov/ecosystems/invasive-species-program/science/invasive-species-tools
|
# Invasive Species Tools
## Science Center Objects
Tracking the establishment and spread of existing and new invasive species is critical to effectively manage invasive species. In addition to standard means of monitoring, the USGS is developing new tools, particularly molecular techniques, to assist in the early detection of invasive species.
eDNA
Environmental DNA (eDNA), a genetic material shed by organisms into the waters in which they live, has recently emerged as a powerful genetic tool for detecting invasive species and rare aquatic animals. This technology involves detection of DNA in an environmental sample, such as lake or river water.
USGS research has led to refinements to past methods to improve detection sensitivity, understand how eDNA changes over time once it’s shed from live fish, and decrease time between sampling and results. Specific USGS research includes developing genetic markers and sampling protocols for species such as Asian carp, Burmese python (Python bivittatus), Argentine Black and White Tegu (Salvator merianae), sunfishes, crayfishes, New Zealand Mudsnail (Potamopyrgus antipodarum), Eurasian watermilfoil (Myriophyllum spicatum) and Northern Pike (Esox lucius).
Genetic Tools for Zebra and Quagga Mussels
Invasive zebra and quagga mussels (collectively called dreissenid mussels) are causing significant ecological and economic impacts and the range of these impacts continues to increase as they spread across North America. USGS conducts dreissenid mussel rapid response research in the Great Lakes and Upper Mississippi River basins including development of genetic tools for dreissenid mussel detection. For example, scientists are evaluating the use of eDNA to help direct dreissenid mussel control efforts on inland lakes, and determining if eDNA can be used to for monitoring even under winter conditions. Scientists are also testing a portable rapid eDNA detection kit for dreissenid mussel detection.
In 2016 the first detection of dreissenid mussel larvae was documented in Montana. This detection triggered the launch of the DOI Invasive Mussel Initiative DOI Invasive Mussel Initiative to identify opportunities for the federal government to strengthen efforts, in coordination with states and tribes, to address invasive mussels in the Columbia River Basin and across the West. In support of this effort, the USGS evaluated genetic markers for dreissenid mussel early detection and is working to improve environmental DNA sampling and analysis protocols. USGS work also included the development of a variety of risk-based, early detection monitoring plans in the Northern Rocky Mountains.
"Lab in a Suitcase" set up in the field to test samples for the fungus (Ceratocystis fimbriata) responsible for Rapid ‘Ōhi‘a Death.
(Credit: Carter Atkinson, USGS. Public domain.)
Lab in a Suitcase
Rapid Ōhia Death is a fungal disease of the ōhia lehua tree that is native to the Hawaiian Islands. USGS scientists worked with collaborators at the USDA Agricultural Research Service to develop, test and validate a field method to detect the fungus that causes Rapid Ohi’a Death in mature trees. This portable "Lab in a Suitcase" allows for rapid detection of the fungus and is being used by the Big Island Invasive Species Committee to detect infected trees. A full report on the methods and field application is available.
USGS has been involved in the response to Rapid Ohi’a Death since its detection in 2015, and is part of the multi-organizational Rapid Ohi’a Death Working Group which was formed to share information and coordinate research, resource management and outreach activities.
Current USGS Research: Pathways for Movement and Rate of Spread of Rapid ‘Ōhi‘a Death on the Island of Hawai‘i
| 2020-10-22T04:49:13 |
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|
https://lammps.sandia.gov/threads/msg73323.html
|
LAMMPS WWW Site - LAMMPS Documentation - LAMMPS Mailing List Archives
Re: [lammps-users] FEP calculation on charged cluster
# Re: [lammps-users] FEP calculation on charged cluster
From: Stefan Paquay Date: Tue, 21 Nov 2017 10:02:01 -0500
The way you are doing it, you are changing the charges of the clusters between 0 and their original charge. Based on your data, it appears their original charge is the optimum. If this is somehow not what you expected, then either what you are doing is not actually what you are doing or your expectation is not correct. I can imagine that if your cluster is charge-stabilized, i.e., U_{charged} < 0, then the "ideal" configuration would be to have charges of infinite size, and hence there is no local optimum in the charge. If that is not the case, read on.
A basic and therefore stupid question: You did run the simulations for different values of lambda right? I found the literature to be quite decent when I dealt with it, I cited the following two articles because I applied Bennett's acceptance ratio but I remember the Mezei papers to be quite good too:
Zwanzig R W. J. Chem. Phys., 22:(1954) 1420–1426.
Bennett C H. J. Comput. Phys., 22:(1976) 245–268.
As for your point of perturbing charge vs. perturbing potential energy:
Typically the potential energy is perturbed, but you can think of a charge perturbation as a potential energy perturbation if you rewrite your potential energy as:
U_{total} = U_{non-charged} + U_{charged} and then rewrite U_{charged} as
U_{charged} = \sum_{i=1}^N\sum_{j=(i+1}}^N q_i q_j (other stuff) -->
U_{charged}(\lambda) = \sum_{i=1}^N\sum_{j=(i+1}}^N (\lambda q_i) (\lambda q_j) (other stuff) = \lambda^2 \sum_{i=1}^N\sum_{j=(i+1}}^N q_i q_j (other stuff)
= \lambda^2 U_{charged}(\lambda = 1}
So in essence you are applying the perturbation
U_{total}(\lambda) = U_{non-charged} + \lambda^2 U_{charged}.
On Tue, Nov 21, 2017 at 9:42 AM, Imanuel Kristanto wrote:
Dear LAMMPS users,
I am currently trying to calculate the free energy difference on silver clusters.
Charge of the cluster is the only parameter being perturbed, this is to be used as the criteria for reduction of the cluster. All silver atoms are +1 charge and equilibrated using qeq with ethlyene glycol (EG) as the solvent.
I calculated the FEP of each cluster (post-process using rerun) at particular time step (i.e. 50,000 step), by repeating the FEP calculation with different lambda. Interaction between silver atoms and EG was "switched off" by using neighbor_modify exclude command.
The following command where used:
compute cluster 1 cluster/atom 2.9
compute cc2 1 chunk/atom c_cluster compress yes
compute size 1 property/chunk cc2 count
fix 2 1 ave/histo 2000 1 2000 0 30 30 c_size mode vector ave one beyond ignore file 1t1_nvt.histo
dump clu 1 custom ${freq_frame2}${lmp_data}_chunk.cltr c_cc2 id
variable agg1 atom "c_cc2==1"
variable agg2 atom "c_cc2==2"
group c1 dynamic 1 var agg1 every 2000
group c2 dynamic 1 var agg2 every 2000
variable dlambda equal 0.1 #(varied from 0.1-1.0)
variable ag equal 1.0*v_dlambda
compute cFEP c1 fep 433 atom charge 1 v_ag volume no
compute cFEP1 c2 fep 433 atom charge 1 v_ag volume no
fix fFEP c1 ave/time 1 1 2000 c_cFEP[1] c_cFEP[2] file bar01.lmp
fix fFEP1 c2 ave/time 1 1 2000 c_cFEP1[1] c_cFEP1[2] file bar02.lmp
group-id = 1 -> silver atoms
However, the FEP calculated on one of the clusters shows the following trend (other clusters show the same trend):
Since all the FEP calculated are negative value even when the lambda = 1, there is no optimum charge can be deduced.
I have tried to study some journals related to FEP calculation, but so far I haven't found FEP calculation with charge perturbation only. Any comments and suggestions are welcome.
Thank you.
--
Best Regards,
Kristanto
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
| 2018-09-21T22:04:04 |
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|
http://dergipark.gov.tr/gujs/issue/38948/455484
|
Yıl 2018, Cilt 31, Sayı 3, Sayfalar 879 - 888 2018-09-01
| | | |
## On the Approximation of Highly Oscillatory Integral Equations Via Radial Kernels
#### Amjad ALI [1] , Zeyad Min ULLAH [2] , Marjan UDDIN [3]
##### 71 108
In this work we used radial kernels for computing more generalized fast oscillatory integral equations. The proposed method is based on radial kernels. The present method is efficient for computing oscillatory integral equations with large oscillation parameters. The proposed method is very robust and capable of handling fast oscillatory integral equations.
Oscillatory integral equations, Interpolation Scheme, Radial kernels
• Brunner. H., “Collocation Methods for Volterra Integral and Related Functional Equations”, Cambridge University Press, Cambridge, (2004).
• Davies. P. J., Duncan. D. B., “Stability and convergence of collocation schemes for retarded potential integral equations”, SIAM journal on numerical analysis, 42(3): 1167-1188, (2004).
• De Hoog. F., Weiss. R., “On the solution of Volterra integral equations of the first kind”, Numerische Mathematik, 21(1): 22-32, (1973).
• Brunner. H., Iserles. A., Norsett. S., “Open problems in the computational solution of Volterra functional equations with highly oscillatory kernels”, Isaac Newton Institute, HOP 2007, (2007).
• Iserles. A., Norsett. S. P, “On quadrature methods for highly oscillatory integrals and their implementation”, BIT Numerical Mathematics, 44(4): 755-772, (2004).
• Linz. P, “Product integration methods for Volterra integral equations of the first kind”, BIT Numerical Mathematics, 11(4): 413-421, (1971).
• Levin. D, “Fast integration of rapidly oscillatory functions”, Journal of Computational and Applied Mathematics, 67(1): 95-101, (1996).
• Levin. D, “Procedures for computing one- and two-dimensional integrals of functions with rapid irregular oscillations”, Math. Comput., 38: 531-538, (1982).
• Longman. I. M., “A method for numerical evaluation of finite integrals of oscillatory functions”, Mathematics of Computation, 14(69): 53-59, (1960).
• Polyanin.A. D., Manzhirov. A. V., “Handbook of Integral Equations”, CRC Press, (2008).
• Chen. R., “Numerical approximation for highly oscillatory {Bessel} transform and applications”, Journal of Mathematical Analysis and Applications, 421(2): 1635-1650, (2015).
• Fasshauer. G., Mc Court. M., “Kernel-based approximation methods using Matlab”, World Scientific Publishing Co Inc, (2015).
• Sarler. B., Vertnik. R., “Meshfree explicit local radial basis function collocation method for diffusion problems”, Computers and mathematics with applications, 51(8): 1269-1282, (2006).
• Uddin. M, Minullah. Z., Ali. A, “On the local kernel based approximation of highly oscillatory integrals”, Miskolc Mathematical Notes, 16(2): 1253-1264, (2015).
• Wang. H., Xiang. S, “Asymptotic expansion and Filon-type methods for a Volterra integral equation with a highly oscillatory kernel”, IMA Journal of Numerical Analysis, 31(2): 469-490, (2010).
• Piessens. R., Branders. M., “Modified Clenshaw-Curtis method for the computation of {Bessel} functions integralsl”, BIT Numerical Mathematics, 23(3): 370-381, (1983).
• Piessens. R., Branders. M., “A survey on numerical methods for the computation of Bessel functions integrals”, Rend. Sem. Mat. Univ. Politec. Torino Fascicolo Speciale. Special Functions: Theory and Computation, 249: 265, (1985).
• Puoskari. M., “A method for computing {Bessel} functions integrals”, Journal of Computational Physics, 75(2): 334-344, (1988).
• Uddin. M., Shah. I. A., Ali. H., “On the numerical solution of evolution equation via soliton kernels”, Gazi University Journel of Science, 28(4): 631-637, (2015).
Birincil Dil en Mühendislik Mathematics Yazar: Amjad ALIÜlke: Turkey Yazar: Zeyad Min ULLAH Yazar: Marjan UDDIN
Bibtex @araştırma makalesi { gujs455484, journal = {Gazi University Journal of Science}, issn = {}, eissn = {2147-1762}, address = {Gazi Üniversitesi}, year = {2018}, volume = {31}, pages = {879 - 888}, doi = {}, title = {On the Approximation of Highly Oscillatory Integral Equations Via Radial Kernels}, key = {cite}, author = {ULLAH, Zeyad Min and UDDIN, Marjan and ALI, Amjad} } APA ALI, A , ULLAH, Z , UDDIN, M . (2018). On the Approximation of Highly Oscillatory Integral Equations Via Radial Kernels. Gazi University Journal of Science, 31 (3), 879-888. Retrieved from http://dergipark.gov.tr/gujs/issue/38948/455484 MLA ALI, A , ULLAH, Z , UDDIN, M . "On the Approximation of Highly Oscillatory Integral Equations Via Radial Kernels". Gazi University Journal of Science 31 (2018): 879-888 Chicago ALI, A , ULLAH, Z , UDDIN, M . "On the Approximation of Highly Oscillatory Integral Equations Via Radial Kernels". Gazi University Journal of Science 31 (2018): 879-888 RIS TY - JOUR T1 - On the Approximation of Highly Oscillatory Integral Equations Via Radial Kernels AU - Amjad ALI , Zeyad Min ULLAH , Marjan UDDIN Y1 - 2018 PY - 2018 N1 - DO - T2 - Gazi University Journal of Science JF - Journal JO - JOR SP - 879 EP - 888 VL - 31 IS - 3 SN - -2147-1762 M3 - UR - Y2 - 2018 ER - EndNote %0 Gazi University Journal of Science On the Approximation of Highly Oscillatory Integral Equations Via Radial Kernels %A Amjad ALI , Zeyad Min ULLAH , Marjan UDDIN %T On the Approximation of Highly Oscillatory Integral Equations Via Radial Kernels %D 2018 %J Gazi University Journal of Science %P -2147-1762 %V 31 %N 3 %R %U ISNAD ALI, Amjad , ULLAH, Zeyad Min , UDDIN, Marjan . "On the Approximation of Highly Oscillatory Integral Equations Via Radial Kernels". Gazi University Journal of Science 31 / 3 (Eylül 2018): 879-888.
| 2019-01-24T05:19:15 |
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|
https://www.itl.nist.gov/div898/software/dataplot/refman1/auxillar/ipl1na.htm
|
Dataplot Vol 1 Vol 2
# IPL1NA
Name:
IPL1NA (SET)
Type:
Set Subcommand
Purpose:
Define the name of the plot file created by the DEVICE 2 command.
Description:
By default, Dataplot names the plot file created by the DEVICE 2 command "dppl1f.dat". This is the name used regardless of the type of device.
There are times when it is convenient to use a different name for the plot file. For example, if you are creating multiplot plots and you would like each of these to go into a separate file (i.e., there will be a sequence of DEVICE 2 ... and DEVICE 2 CLOSE commands). Other reasons are to identify the type of output file (e.g., you want a ".ps" extension for Postscript files) or you want to save the file with a unique name for subsequent use after the Dataplot session.
To set the name of the plot file, do the following
SET IPL1NA <file-name>
DEVICE 2 POSTSCRIPT
Note that the SET IPL1NA command must come before the DEVICE 2 command since the plot file is opened when the DEVICE 2 command is entered.
Syntax:
SET IPL1NA <string>
where <string> contains the desired name for the plot file.
Examples:
SET IPL1NA PLOT.PS
SET IPL1NA PLOT1.JPG
Note:
File names have the following restrictions:
1. The file name should be a valid file name for the local operating system.
2. Most Dataplot commands that utilize a file name expect that the file name should contain a period "." in the file name itself or as a trailing character. However, this is not required by the SET IPL1NA command.
3. If the file name contains spaces or hyphens, then it needs to be enclosed in quotes.
4. File names are currently limited to 80 characters. This can in particular be a problem if the file name is contained within a long path name.
You can use the CD command to make the path where the file is stored the current directory. This is most useful for data files. For example,
pwd
cd <path where plot file will be saved>
set ipl1na plot.ps
device 2 postscript
cd ^CURDIR
The pwd command is used to save the current directory. The cd command is then used to set the current directory to the path where the data resides, the read is performed, and then the cd command is used to restore the original working directory (the cd command saves the current path in the string CURDIR).
Note:
File names are case sensitive on Unix/Linux/Mac OS X systems. For these systems, the case of the file name will be as it is entered on the SET IPL1NA command.
As a further caution for Unix/Linux hosts, certain expansion characters (specifically ~ to refer to your home directory) are interpreted by the shell and are not recognized by the Fortran compiler. These expansion characters are interpreted as literal characters and do not yield the intended file name.
Default:
The default name is dppl1f.dat.
Synonyms:
None
Related Commands:
SET FILE SWITCHES = Probe the values for certain file names and the associated unit numbers and file status. DEVICE = Specify a graphics device. SET IPL2NA = Specify the file name for the DEVICE 3 output.
Applications:
Plotting
Implementation Date:
Pre-1987
Program:
SET IPL1NA plot1.ps
DEVICE 2 POSTSCRIPT
PLOT X**2 FOR X = 1 1 9
DEVICE 2 CLOSE
.
SET IPL1NA plot2.ps
DEVICE 2 POSTSCRIPT
PLOT X**3 FOR X = 1 1 9
DEVICE 2 CLOSE
NIST is an agency of the U.S. Commerce Department.
Date created: 05/09/2016
Last updated: 05/09/2016
| 2018-05-24T19:22:33 |
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|
https://zbmath.org/authors/?q=ai%3Aharris.michael-howard
|
# zbMATH — the first resource for mathematics
## Harris, Michael Howard
Compute Distance To:
Author ID: harris.michael-howard Published as: Harris, M.; Harris, Michael External Links: MGP · Wikidata · GND Awards: Clay Research Award (2007)
Documents Indexed: 100 Publications since 1979, including 8 Books
all top 5
#### Co-Authors
54 single-authored 7 Taylor, Richard Lawrence 4 Kudla, Stephen S. 4 Li, Jian-Shu 4 Zucker, Steven Mark 3 Chaudouard, Pierre-Henri 3 Laumon, Gérard 3 Skinner, Christopher M. 3 Tilouine, Jacques 2 Carayol, Henri 2 Clozel, Laurent 2 Grobner, Harald 2 Haines, Thomas J. 2 Labesse, Jean-Pierre 2 Lapid, Erez Moshe 2 Soudry, David 2 Thorne, Jack A. 2 Vignéras, Marie-France 1 Barnet-Lamb, Thomas 1 Blasius, Don 1 Böckle, Gebhard 1 Chenevier, Gaëtan 1 Cogdell, James W. 1 Devlin, Keith J. 1 Eischen, Ellen Elizabeth 1 Esnault, Hélène 1 Garrett, Paul Brittingham 1 Geraghty, David 1 Ginzburg, David 1 Guralnick, Robert Michael 1 Jackson, Allyn 1 Jacquet, Hervé Michel 1 Jakobsen, Hans Plesner 1 Jiang, Dihua 1 Katz, Nicholas Michael 1 Khare, Chandrashekhar 1 Lan, Kai-Wen 1 Li, Jianshu 1 Lin, Jie 1 Ngô Bao Châu 1 Odlyzko, Andrew M. 1 Phong, Duong Hong 1 Pitale, Ameya 1 Ponomare, Paul 1 Ramakrishnan, Dinakar 1 Schiffmann, Gérard 1 Scholl, Anthony James 1 Shepherd-Barron, Nicholas Ian 1 Stanton, Bob 1 Sun, Binyong 1 Sweet, William J. 1 Venkatesh, Akshay
all top 5
#### Serials
8 Inventiones Mathematicae 5 Compositio Mathematica 4 Duke Mathematical Journal 3 Mathematische Annalen 3 Notices of the American Mathematical Society 3 Annals of Mathematics. Second Series 2 The Mathematical Intelligencer 2 Annales Scientifiques de l’École Normale Supérieure. Quatrième Série 2 Journal für die Reine und Angewandte Mathematik 2 Journal of the American Mathematical Society 2 IMRN. International Mathematics Research Notices 2 The Asian Journal of Mathematics 2 Journal of the European Mathematical Society (JEMS) 2 Astérisque 1 American Mathematical Monthly 1 Indian Journal of Pure & Applied Mathematics 1 Acta Mathematica 1 American Journal of Mathematics 1 Gazette des Mathématiciens 1 Publications Mathématiques 1 Journal of Algebra 1 Journal of Differential Geometry 1 Journal of Mathematics of Kyoto University 1 Pacific Journal of Mathematics 1 Proceedings of the London Mathematical Society. Third Series 1 Publications of the Research Institute for Mathematical Sciences, Kyoto University 1 Internationale Mathematische Nachrichten 1 Forum Mathematicum 1 Mémoires de la Société Mathématique de France. Nouvelle Série 1 Comptes Rendus de l’Académie des Sciences. Série I 1 Annales de la Faculté des Sciences de Toulouse. Mathématiques. Série VI 1 Experimental Mathematics 1 Journal of Algebraic Geometry 1 Documenta Mathematica 1 European Mathematical Society Newsletter 1 Journal of the Institute of Mathematics of Jussieu 1 Pure and Applied Mathematics Quarterly 1 Annals of Mathematics Studies 1 London Mathematical Society Lecture Note Series 1 Algebra & Number Theory 1 Japanese Journal of Mathematics. 3rd Series 1 Forum of Mathematics, Pi 1 Lettera Matematica. International Edition 1 Annales Mathématiques du Québec 1 Cambridge Journal of Mathematics 1 Research in the Mathematical Sciences
all top 5
#### Fields
83 Number theory (11-XX) 41 Algebraic geometry (14-XX) 35 Topological groups, Lie groups (22-XX) 11 General and overarching topics; collections (00-XX) 6 History and biography (01-XX) 5 Group theory and generalizations (20-XX) 5 Several complex variables and analytic spaces (32-XX) 1 Mathematical logic and foundations (03-XX) 1 Associative rings and algebras (16-XX) 1 Nonassociative rings and algebras (17-XX) 1 Ordinary differential equations (34-XX) 1 Abstract harmonic analysis (43-XX) 1 Differential geometry (53-XX) 1 Global analysis, analysis on manifolds (58-XX) 1 Quantum theory (81-XX)
#### Citations contained in zbMATH
79 Publications have been cited 1,375 times in 829 Documents Cited by Year
The geometry and cohomology of some simple Shimura varieties. With an appendix by Vladimir G. Berkovich. Zbl 1036.11027
Harris, Michael; Taylor, Richard
2001
Automorphy for some $$l$$-adic lifts of automorphic mod $$l$$ Galois representations. With Appendix A, summarizing unpublished work of Russ Mann, and Appendix B by Marie-France Vignéras. Zbl 1169.11020
Clozel, Laurent; Harris, Michael; Taylor, Richard
2008
A family of Calabi-Yau varieties and potential automorphy. II. Zbl 1264.11044
Barnet-Lamb, Tom; Geraghty, David; Harris, Michael; Taylor, Richard
2011
A family of Calabi-Yau varieties and potential automorphy. Zbl 1263.11061
Harris, Michael; Shepherd-Barron, Nick; Taylor, Richard
2010
Theta dichotomy for unitary groups. Zbl 0870.11026
Harris, Michael; Kudla, Stephen S.; Sweet, William J.
1996
The central critical value of a triple product $$L$$-function. Zbl 0731.11031
Harris, Michael; Kudla, Stephen S.
1991
Construction of automorphic Galois representations. II. Zbl 1310.11062
Chenevier, Gaëtan; Harris, Michael
2013
$$l$$-adic representations associated to modular forms over imaginary quadratic fields. I: Lifting to $$GSp_ 4(\mathbb{Q})$$. Zbl 0797.11047
Harris, Michael; Soudry, David; Taylor, Richard
1993
Special values of zeta functions attached to Siegel modular forms. Zbl 0465.10022
Harris, Michael
1981
Arithmetic automorphic forms for the nonholomorphic discrete series of $$GSp(2)$$. Zbl 0786.11031
Harris, Michael; Kudla, Stephen S.
1992
Eisenstein series on Shimura varieties. Zbl 0589.10030
Harris, Michael
1984
On the rigid cohomology of certain Shimura varieties. Zbl 1410.11040
Harris, Michael; Lan, Kai-Wen; Taylor, Richard; Thorne, Jack
2016
Arithmetic vector bundles and automorphic forms on Shimura varieties. I. Zbl 0598.14019
Harris, Michael
1985
The rationality of holomorphic Eisenstein series. Zbl 0452.10031
Harris, Michael
1981
Supercuspidal representations in the cohomology of Drinfel’d upper half spaces; elaboration of Carayol’s program. Zbl 0886.11029
Harris, Michael
1997
$$L$$-functions and periods of polarized regular motives. Zbl 0859.11032
Harris, Michael
1997
Functorial properties of toroidal compactifications of locally symmetric varieties. Zbl 0711.14011
Harris, Michael
1989
Arithmetic vector bundles and automorphic forms on Shimura varieties. II. Zbl 0612.14019
Harris, Michael
1986
Conditional base change for unitary groups. Zbl 1071.22025
Harris, Michael; Labesse, Jean-Pierre
2004
A Lefschetz property for subvarieties of Shimura varieties. Zbl 0954.14016
Harris, Michael; Li, Jian-Shu
1998
Automorphic forms of $${\bar \partial}$$-cohomology type as coherent cohomology classes. Zbl 0711.14012
Harris, Michael
1990
Potential automorphy of odd-dimensional symmetric powers of elliptic curves and applications. Zbl 1234.11068
Harris, Michael
2009
On a conjecture of Jacquet. Zbl 1080.11039
Harris, Michael; Kudla, Stephen S.
2004
$$L$$-functions of $$2 \times 2$$ unitary groups and factorization of periods of Hilbert modular forms. Zbl 0779.11023
Harris, Michael
1993
Special values of triple product $$L$$-functions. Zbl 0776.11027
Garrett, Paul B.; Harris, Michael
1993
$$p$$-adic representations arising from descent on Abelian varieties. Zbl 0417.14034
Harris, Michael
1979
Systematic growth of Mordell-Weil groups of abelian varieties in towers of number fields. Zbl 0429.14013
Harris, Michael
1979
$$p$$-adic $$L$$-functions for unitary Shimura varieties. I: Construction of the Eisenstein measure. Zbl 1143.11019
Harris, Michael; Li, Jian-Shu; Skinner, Christopher M.
2007
Stabilization of the trace formula, Shimura varieties, and arithmetic applications. Volume 1: On the stabilization of the trace formula. Zbl 1255.11027
Clozel, Laurent (ed.); Harris, Michael (ed.); Labesse, Jean-Pierre (ed.); Ngô, Bao-Châu (ed.)
2011
Coherent cohomology, limits of discrete series, and Galois conjugation. Zbl 0811.11034
Blasius, Don; Harris, Michael; Ramakrishnan, Dinakar
1994
Whittaker periods, motivic periods, and special values of tensor product $$L$$-functions. Zbl 1423.11096
Grobner, Harald; Harris, Michael
2016
$$L$$-functions and periods of adjoint motives. Zbl 1319.11028
Harris, Michael
2013
Singular holomorphic representations and singular modular forms. Zbl 0466.32017
Harris, Michael; Jakobsen, Hans Plesner
1982
Beilinson-Bernstein localization over $$\mathbb{Q}$$ and periods of automorphic forms. Zbl 1355.11058
Harris, Michael
2013
A simple proof of rationality of Siegel-Weil Eisenstein series. Zbl 1225.11069
Harris, Michael
2008
Cohomological automorphic forms on unitary groups. II. Period relations and values of $$L$$-functions. Zbl 1390.11088
Harris, Michael
2007
The Rallis inner product formula and $$p$$-adic $$L$$-functions. Zbl 1103.11017
Harris, Michael; Li, Jian-Shu; Skinner, Christopher M.
2005
The local Langlands conjecture for $$GL(n)$$ over a $$p$$-adic field, $$n<p$$. Zbl 0921.11060
Harris, Michael
1998
Boundary cohomology of Shimura varieties. II: Hodge theory at the boundary. Zbl 0860.11031
Harris, Michael; Zucker, Steven
1994
Regular models of certain Shimura varieties. Zbl 1008.11022
Harris, Michael; Taylor, Richard
2002
Boundary cohomology of Shimura varieties. III: Coherent cohomology on higher-rank boundary strata and applications to Hodge theory. Zbl 1020.11042
Harris, Michael; Zucker, Steven
2001
$$p$$-adic measures and square roots of special values of triple product $$L$$-functions. Zbl 1034.11034
Harris, Michael; Tilouine, Jacques
2001
Correction to: $$p$$-adic representations arising from descent on Abelian varieties. Zbl 1060.14524
Harris, Michael
2000
Hodge-de Rham structures and periods of automorphic forms. Zbl 0824.14015
Harris, Michael
1994
A note on three lemmas of Shimura. Zbl 0433.10016
Harris, Michael
1979
On the local Langlands correspondence. Zbl 1151.11351
Harris, Michael
2002
Period invariants of Hilbert modular forms. I: Trilinear differential operators and L-functions. Zbl 0716.11020
Harris, Michael
1990
The Taylor-Wiles method for coherent cohomology. Zbl 1276.11102
Harris, Michael
2013
Theta correspondences for close unitary groups. Zbl 1304.22024
Harris, Michael; Li, Jian-Shu; Sun, Binyong
2011
Occult period invariants and critical values of the degree four $$L$$-function of $$\mathrm{GSp}(4)$$. Zbl 1173.11329
Harris, Michael
2004
Automorphic forms and the cohomology of vector bundles on Shimura varieties. Zbl 0716.14011
Harris, Michael
1990
Whittaker rational structures and special values of the Asai $$L$$-function. Zbl 1418.11090
Grobner, Harald; Harris, Michael; Lapid, Erez
2016
Galois representations, automorphic forms, and the Sato-Tate conjecture. Zbl 1365.11064
Harris, Michael
2014
Non-vanishing of L-functions of $$2 \times 2$$ unitary groups. Zbl 0779.11024
Harris, Michael
1993
Cohomologie de Dolbeault à croissance logarithmique à l’infini. (Dolbeault cohomology with logarithmic growth at infinity). Zbl 0597.32025
Harris, Michael; Phong, D. H.
1986
Maass operators and Eisenstein series. Zbl 0455.10018
Harris, Michael
1981
Arithmetic applications of the Langlands program. Zbl 1203.11040
Harris, Michael
2010
Local Langlands correspondences and vanishing cycles on Shimura varieties. Zbl 1025.11038
Harris, Michael
2001
Boundary cohomology of Shimura varieties. I: Coherent cohomology on toroidal compactifications. Zbl 0860.11030
Harris, Michael; Zucker, Steven
1994
Speculations on the mod $$p$$ representation theory of $$p$$-adic groups. Zbl 1362.22022
Harris, Michael
2016
Mathematics without apologies. Portrait of a problematic vocation. Zbl 1386.00008
Harris, Michael
2015
A note on trilinear forms for reducible representations and Beilinson’s conjectures. Zbl 1060.11040
Harris, M.; Scholl, A. J.
2001
Galois properties of cohomological automorphic forms on GL$$(n)$$. Zbl 1017.11026
Harris, Michael
1999
Period invariants of Hilbert modular forms. II. Zbl 0871.11037
Harris, Michael
1994
The annihilators of p-adic induced modules. Zbl 0448.22009
Harris, Michael
1980
Derived Hecke algebra for weight one forms. Zbl 07093495
Harris, Michael; Venkatesh, Akshay
2019
$$p$$-adic and analytic properties of period integrals and values of $$L$$-functions. Zbl 1417.11117
Harris, Michael
2016
Automorphic realization of residual Galois representations. Zbl 1257.11051
Guralnick, Robert; Harris, Michael; Katz, Nicholas M.
2010
Covariant differential operators. Zbl 0529.22015
Harris, Michael
1983
Harris, Michael
1982
Kubert-Lang units and elliptic curves without complex multiplication. Zbl 0434.12008
Harris, Michael
1980
$$p$$-adic $$L$$-functions for unitary groups. Zbl 07209559
Eischen, Ellen; Harris, Michael; Li, Jianshu; Skinner, Christopher
2020
Chern classes of automorphic vector bundles. Zbl 1398.14017
Esnault, Hélène; Harris, Michael
2017
The local Langlands correspondence: notes of (half) a course at the IHP Spring 2000. Zbl 1084.11028
Harris, Michael
2005
A sometimes funny book supposedly about infinity – a review of “Everything and more”. Zbl 1168.00303
Harris, Michael
2004
Contexts of justification. Zbl 1055.00509
Harris, Michael
2001
Cohomological automorphic forms on unitary groups. I: Rationality of the theta correspondence. Zbl 1005.11020
Harris, Michael
1999
Erratum: “Boundary cohomology of Shimura varieties. II: Hodge theory at the boundary”. Zbl 1008.11529
Harris, M.; Zucker, S.
1995
Arithmetic vector bundles of Shimura varieties. Zbl 0571.10031
Harris, Michael
1984
$$p$$-adic $$L$$-functions for unitary groups. Zbl 07209559
Eischen, Ellen; Harris, Michael; Li, Jianshu; Skinner, Christopher
2020
Derived Hecke algebra for weight one forms. Zbl 07093495
Harris, Michael; Venkatesh, Akshay
2019
Chern classes of automorphic vector bundles. Zbl 1398.14017
Esnault, Hélène; Harris, Michael
2017
On the rigid cohomology of certain Shimura varieties. Zbl 1410.11040
Harris, Michael; Lan, Kai-Wen; Taylor, Richard; Thorne, Jack
2016
Whittaker periods, motivic periods, and special values of tensor product $$L$$-functions. Zbl 1423.11096
Grobner, Harald; Harris, Michael
2016
Whittaker rational structures and special values of the Asai $$L$$-function. Zbl 1418.11090
Grobner, Harald; Harris, Michael; Lapid, Erez
2016
Speculations on the mod $$p$$ representation theory of $$p$$-adic groups. Zbl 1362.22022
Harris, Michael
2016
$$p$$-adic and analytic properties of period integrals and values of $$L$$-functions. Zbl 1417.11117
Harris, Michael
2016
Mathematics without apologies. Portrait of a problematic vocation. Zbl 1386.00008
Harris, Michael
2015
Galois representations, automorphic forms, and the Sato-Tate conjecture. Zbl 1365.11064
Harris, Michael
2014
Construction of automorphic Galois representations. II. Zbl 1310.11062
Chenevier, Gaëtan; Harris, Michael
2013
$$L$$-functions and periods of adjoint motives. Zbl 1319.11028
Harris, Michael
2013
Beilinson-Bernstein localization over $$\mathbb{Q}$$ and periods of automorphic forms. Zbl 1355.11058
Harris, Michael
2013
The Taylor-Wiles method for coherent cohomology. Zbl 1276.11102
Harris, Michael
2013
A family of Calabi-Yau varieties and potential automorphy. II. Zbl 1264.11044
Barnet-Lamb, Tom; Geraghty, David; Harris, Michael; Taylor, Richard
2011
Stabilization of the trace formula, Shimura varieties, and arithmetic applications. Volume 1: On the stabilization of the trace formula. Zbl 1255.11027
Clozel, Laurent (ed.); Harris, Michael (ed.); Labesse, Jean-Pierre (ed.); Ngô, Bao-Châu (ed.)
2011
Theta correspondences for close unitary groups. Zbl 1304.22024
Harris, Michael; Li, Jian-Shu; Sun, Binyong
2011
A family of Calabi-Yau varieties and potential automorphy. Zbl 1263.11061
Harris, Michael; Shepherd-Barron, Nick; Taylor, Richard
2010
Arithmetic applications of the Langlands program. Zbl 1203.11040
Harris, Michael
2010
Automorphic realization of residual Galois representations. Zbl 1257.11051
Guralnick, Robert; Harris, Michael; Katz, Nicholas M.
2010
Potential automorphy of odd-dimensional symmetric powers of elliptic curves and applications. Zbl 1234.11068
Harris, Michael
2009
Automorphy for some $$l$$-adic lifts of automorphic mod $$l$$ Galois representations. With Appendix A, summarizing unpublished work of Russ Mann, and Appendix B by Marie-France Vignéras. Zbl 1169.11020
Clozel, Laurent; Harris, Michael; Taylor, Richard
2008
A simple proof of rationality of Siegel-Weil Eisenstein series. Zbl 1225.11069
Harris, Michael
2008
$$p$$-adic $$L$$-functions for unitary Shimura varieties. I: Construction of the Eisenstein measure. Zbl 1143.11019
Harris, Michael; Li, Jian-Shu; Skinner, Christopher M.
2007
Cohomological automorphic forms on unitary groups. II. Period relations and values of $$L$$-functions. Zbl 1390.11088
Harris, Michael
2007
The Rallis inner product formula and $$p$$-adic $$L$$-functions. Zbl 1103.11017
Harris, Michael; Li, Jian-Shu; Skinner, Christopher M.
2005
The local Langlands correspondence: notes of (half) a course at the IHP Spring 2000. Zbl 1084.11028
Harris, Michael
2005
Conditional base change for unitary groups. Zbl 1071.22025
Harris, Michael; Labesse, Jean-Pierre
2004
On a conjecture of Jacquet. Zbl 1080.11039
Harris, Michael; Kudla, Stephen S.
2004
Occult period invariants and critical values of the degree four $$L$$-function of $$\mathrm{GSp}(4)$$. Zbl 1173.11329
Harris, Michael
2004
A sometimes funny book supposedly about infinity – a review of “Everything and more”. Zbl 1168.00303
Harris, Michael
2004
Regular models of certain Shimura varieties. Zbl 1008.11022
Harris, Michael; Taylor, Richard
2002
On the local Langlands correspondence. Zbl 1151.11351
Harris, Michael
2002
The geometry and cohomology of some simple Shimura varieties. With an appendix by Vladimir G. Berkovich. Zbl 1036.11027
Harris, Michael; Taylor, Richard
2001
Boundary cohomology of Shimura varieties. III: Coherent cohomology on higher-rank boundary strata and applications to Hodge theory. Zbl 1020.11042
Harris, Michael; Zucker, Steven
2001
$$p$$-adic measures and square roots of special values of triple product $$L$$-functions. Zbl 1034.11034
Harris, Michael; Tilouine, Jacques
2001
Local Langlands correspondences and vanishing cycles on Shimura varieties. Zbl 1025.11038
Harris, Michael
2001
A note on trilinear forms for reducible representations and Beilinson’s conjectures. Zbl 1060.11040
Harris, M.; Scholl, A. J.
2001
Contexts of justification. Zbl 1055.00509
Harris, Michael
2001
Correction to: $$p$$-adic representations arising from descent on Abelian varieties. Zbl 1060.14524
Harris, Michael
2000
Galois properties of cohomological automorphic forms on GL$$(n)$$. Zbl 1017.11026
Harris, Michael
1999
Cohomological automorphic forms on unitary groups. I: Rationality of the theta correspondence. Zbl 1005.11020
Harris, Michael
1999
A Lefschetz property for subvarieties of Shimura varieties. Zbl 0954.14016
Harris, Michael; Li, Jian-Shu
1998
The local Langlands conjecture for $$GL(n)$$ over a $$p$$-adic field, $$n<p$$. Zbl 0921.11060
Harris, Michael
1998
Supercuspidal representations in the cohomology of Drinfel’d upper half spaces; elaboration of Carayol’s program. Zbl 0886.11029
Harris, Michael
1997
$$L$$-functions and periods of polarized regular motives. Zbl 0859.11032
Harris, Michael
1997
Theta dichotomy for unitary groups. Zbl 0870.11026
Harris, Michael; Kudla, Stephen S.; Sweet, William J.
1996
Erratum: “Boundary cohomology of Shimura varieties. II: Hodge theory at the boundary”. Zbl 1008.11529
Harris, M.; Zucker, S.
1995
Coherent cohomology, limits of discrete series, and Galois conjugation. Zbl 0811.11034
Blasius, Don; Harris, Michael; Ramakrishnan, Dinakar
1994
Boundary cohomology of Shimura varieties. II: Hodge theory at the boundary. Zbl 0860.11031
Harris, Michael; Zucker, Steven
1994
Hodge-de Rham structures and periods of automorphic forms. Zbl 0824.14015
Harris, Michael
1994
Boundary cohomology of Shimura varieties. I: Coherent cohomology on toroidal compactifications. Zbl 0860.11030
Harris, Michael; Zucker, Steven
1994
Period invariants of Hilbert modular forms. II. Zbl 0871.11037
Harris, Michael
1994
$$l$$-adic representations associated to modular forms over imaginary quadratic fields. I: Lifting to $$GSp_ 4(\mathbb{Q})$$. Zbl 0797.11047
Harris, Michael; Soudry, David; Taylor, Richard
1993
$$L$$-functions of $$2 \times 2$$ unitary groups and factorization of periods of Hilbert modular forms. Zbl 0779.11023
Harris, Michael
1993
Special values of triple product $$L$$-functions. Zbl 0776.11027
Garrett, Paul B.; Harris, Michael
1993
Non-vanishing of L-functions of $$2 \times 2$$ unitary groups. Zbl 0779.11024
Harris, Michael
1993
Arithmetic automorphic forms for the nonholomorphic discrete series of $$GSp(2)$$. Zbl 0786.11031
Harris, Michael; Kudla, Stephen S.
1992
The central critical value of a triple product $$L$$-function. Zbl 0731.11031
Harris, Michael; Kudla, Stephen S.
1991
Automorphic forms of $${\bar \partial}$$-cohomology type as coherent cohomology classes. Zbl 0711.14012
Harris, Michael
1990
Period invariants of Hilbert modular forms. I: Trilinear differential operators and L-functions. Zbl 0716.11020
Harris, Michael
1990
Automorphic forms and the cohomology of vector bundles on Shimura varieties. Zbl 0716.14011
Harris, Michael
1990
Functorial properties of toroidal compactifications of locally symmetric varieties. Zbl 0711.14011
Harris, Michael
1989
Arithmetic vector bundles and automorphic forms on Shimura varieties. II. Zbl 0612.14019
Harris, Michael
1986
Cohomologie de Dolbeault à croissance logarithmique à l’infini. (Dolbeault cohomology with logarithmic growth at infinity). Zbl 0597.32025
Harris, Michael; Phong, D. H.
1986
Arithmetic vector bundles and automorphic forms on Shimura varieties. I. Zbl 0598.14019
Harris, Michael
1985
Eisenstein series on Shimura varieties. Zbl 0589.10030
Harris, Michael
1984
Arithmetic vector bundles of Shimura varieties. Zbl 0571.10031
Harris, Michael
1984
Covariant differential operators. Zbl 0529.22015
Harris, Michael
1983
Singular holomorphic representations and singular modular forms. Zbl 0466.32017
Harris, Michael; Jakobsen, Hans Plesner
1982
Harris, Michael
1982
Special values of zeta functions attached to Siegel modular forms. Zbl 0465.10022
Harris, Michael
1981
The rationality of holomorphic Eisenstein series. Zbl 0452.10031
Harris, Michael
1981
Maass operators and Eisenstein series. Zbl 0455.10018
Harris, Michael
1981
The annihilators of p-adic induced modules. Zbl 0448.22009
Harris, Michael
1980
Kubert-Lang units and elliptic curves without complex multiplication. Zbl 0434.12008
Harris, Michael
1980
$$p$$-adic representations arising from descent on Abelian varieties. Zbl 0417.14034
Harris, Michael
1979
Systematic growth of Mordell-Weil groups of abelian varieties in towers of number fields. Zbl 0429.14013
Harris, Michael
1979
A note on three lemmas of Shimura. Zbl 0433.10016
Harris, Michael
1979
all top 5
#### Cited by 668 Authors
29 Harris, Michael Howard 22 Gee, Toby 12 Geraghty, David 12 Taylor, Richard Lawrence 12 Thorne, Jack A. 11 Clozel, Laurent 10 Gan, Wee Teck 10 Henniart, Guy M. 10 Ichino, Atsushi 10 Jiang, Dihua 9 Calegari, Frank 9 Lan, Kai-Wen 9 Shin, Sug Woo 8 Bergeron, Nicolas 8 Böcherer, Siegfried 8 Kudla, Stephen S. 8 Panchishkin, Alexei A. 8 Plymen, Roger J. 8 Shparlinski, Igor E. 7 Aubert, Anne-Marie 7 Berger, Tobias 7 Bushnell, Colin J. 7 Emerton, Matthew 7 Herzig, Florian 7 Pitale, Ameya 7 Scholze, Peter 6 Barnet-Lamb, Thomas 6 Chenevier, Gaëtan 6 Hida, Haruzo 6 Lu, Guangshi 6 Mizumoto, Shin-ichiro 6 Moeglin, Colette 6 Prasad, Dipendra 6 Sun, Binyong 6 Virdol, Cristian 5 Baum, Paul Frank 5 Eischen, Ellen Elizabeth 5 Grobner, Harald 5 Gross, Benedict Hyman 5 Johansson, Christian 5 Kobayashi, Toshiyuki 5 Lanphier, Dominic 5 Le, Daniel 5 Mantovan, Elena 5 Shahidi, Freydoon 5 Solleveld, Maarten 5 Stroh, Benoît 5 Takeda, Shuichiro 5 Urban, Eric 5 Wu, Jie 4 Bouganis, Thanasis 4 Boyer, Pascal 4 Caraiani, Ana 4 Choiy, Kwangho 4 Dat, Jean-François 4 Elliott, Peter D. T. A. 4 Friedberg, Solomon 4 Ginzburg, David 4 Görtz, Ulrich 4 Guerberoff, Lucio 4 James, Kevin 4 Januszewski, Fabian 4 Kumar, Narasimha 4 Le Hung, Bao V. 4 Levin, Brandon 4 Mazur, Barry 4 Mieda, Yoichi 4 Morra, Stefano 4 Nelson, Paul D. 4 Newton, James 4 Patrikis, Stefan T. 4 Rallis, Stephen James 4 Saha, Abhishek 4 Sarnak, Peter Clive 4 Schmidt, Ralf 4 Sorensen, Claus Mazanti 4 Sutherland, Andrew V. 4 Takloo-Bighash, Ramin 4 Templier, Nicolas 4 Thorner, Jesse 4 Wang, Yingnan 4 Xu, Bin 4 Xue, Hang 4 Yamana, Shunsuke 4 Zhang, Wei 4 Zucker, Steven Mark 3 Atobe, Hiraku 3 Blomer, Valentin 3 Burgos, José Ignacio 3 Darmon, Henri René 3 de Shalit, Ehud 3 Dieulefait, Luis Victor 3 González, Josep R. 3 Goren, Eyal Z. 3 Gun, Sanoli 3 Heim, Bernhard Ernst 3 Hiraga, Kaoru 3 Hoffstein, Jeffrey 3 Hsieh, Ming-Lun 3 Inam, Ilker ...and 568 more Authors
all top 5
#### Cited in 114 Serials
66 Journal of Number Theory 46 Inventiones Mathematicae 44 Compositio Mathematica 44 Duke Mathematical Journal 42 Mathematische Annalen 26 International Journal of Number Theory 25 Transactions of the American Mathematical Society 24 Mathematische Zeitschrift 23 Israel Journal of Mathematics 22 Manuscripta Mathematica 21 Journal of the American Mathematical Society 19 Bulletin of the American Mathematical Society. New Series 17 Advances in Mathematics 17 Journal of the Institute of Mathematics of Jussieu 16 Forum Mathematicum 15 Annales de l’Institut Fourier 15 Annals of Mathematics. Second Series 13 Memoirs of the American Mathematical Society 13 The Ramanujan Journal 12 Journal für die Reine und Angewandte Mathematik 12 Proceedings of the American Mathematical Society 11 Journal of Algebra 10 Annales Scientifiques de l’École Normale Supérieure. Quatrième Série 10 Forum of Mathematics, Sigma 10 Research in the Mathematical Sciences 9 Documenta Mathematica 9 Comptes Rendus. Mathématique. Académie des Sciences, Paris 8 Annales Mathématiques du Québec 8 Research in Number Theory 7 Annales de la Faculté des Sciences de Toulouse. Mathématiques. Série VI 6 Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg 6 Journal of Algebraic Geometry 6 Algebra & Number Theory 6 Journal de l’École Polytechnique – Mathématiques 5 Acta Arithmetica 5 Publications Mathématiques 5 Pacific Journal of Mathematics 5 Proceedings of the Japan Academy. Series A 5 Journal de Théorie des Nombres de Bordeaux 5 Selecta Mathematica. New Series 5 Representation Theory 5 Science China. Mathematics 5 Forum of Mathematics, Pi 4 Mathematics of Computation 4 Archiv der Mathematik 4 Canadian Journal of Mathematics 4 Functiones et Approximatio. Commentarii Mathematici 4 Glasgow Mathematical Journal 4 Journal of the Mathematical Society of Japan 4 Journal of the European Mathematical Society (JEMS) 3 Mathematical Proceedings of the Cambridge Philosophical Society 3 Rocky Mountain Journal of Mathematics 3 Acta Mathematica Vietnamica 3 Monatshefte für Mathematik 3 Experimental Mathematics 3 LMS Journal of Computation and Mathematics 3 Acta Mathematica Sinica. English Series 2 Communications in Algebra 2 Indian Journal of Pure & Applied Mathematics 2 Journal of Functional Analysis 2 Journal of the London Mathematical Society. Second Series 2 Journal of Soviet Mathematics 2 Nagoya Mathematical Journal 2 Publications of the Research Institute for Mathematical Sciences, Kyoto University 2 Tohoku Mathematical Journal. Second Series 2 Advances in Applied Mathematics 2 Revista Matemática Iberoamericana 2 Geometric and Functional Analysis. GAFA 2 Mémoires de la Société Mathématique de France. Nouvelle Série 2 Indagationes Mathematicae. New Series 2 Transformation Groups 2 Taiwanese Journal of Mathematics 2 Japanese Journal of Mathematics. 3rd Series 1 Bulletin of the Australian Mathematical Society 1 Jahresbericht der Deutschen Mathematiker-Vereinigung (DMV) 1 Journal of Mathematical Analysis and Applications 1 Lithuanian Mathematical Journal 1 The Mathematical Intelligencer 1 Acta Mathematica 1 Annali della Scuola Normale Superiore di Pisa. Classe di Scienze. Serie IV 1 Bulletin of the London Mathematical Society 1 Geometriae Dedicata 1 International Journal of Mathematics and Mathematical Sciences 1 Kodai Mathematical Journal 1 Mathematische Nachrichten 1 Proceedings of the London Mathematical Society. Third Series 1 Synthese 1 Tokyo Journal of Mathematics 1 European Journal of Combinatorics 1 Acta Mathematica Hungarica 1 Journal of the Ramanujan Mathematical Society 1 Science in China. Series A 1 International Journal of Mathematics 1 Differential Geometry and its Applications 1 IMRN. International Mathematics Research Notices 1 Journal de Mathématiques Pures et Appliquées. Neuvième Série 1 Expositiones Mathematicae 1 Cybernetics and Systems Analysis 1 Journal of Mathematical Sciences (New York) 1 Journal of Lie Theory ...and 14 more Serials
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#### Cited in 34 Fields
720 Number theory (11-XX) 233 Topological groups, Lie groups (22-XX) 189 Algebraic geometry (14-XX) 52 Group theory and generalizations (20-XX) 14 Several complex variables and analytic spaces (32-XX) 11 Commutative algebra (13-XX) 11 Associative rings and algebras (16-XX) 11 Global analysis, analysis on manifolds (58-XX) 10 Differential geometry (53-XX) 6 $$K$$-theory (19-XX) 6 Special functions (33-XX) 5 Field theory and polynomials (12-XX) 5 Nonassociative rings and algebras (17-XX) 5 Algebraic topology (55-XX) 4 General and overarching topics; collections (00-XX) 4 Mathematical logic and foundations (03-XX) 4 Combinatorics (05-XX) 3 History and biography (01-XX) 3 Category theory; homological algebra (18-XX) 3 Abstract harmonic analysis (43-XX) 3 Functional analysis (46-XX) 2 Dynamical systems and ergodic theory (37-XX) 2 Probability theory and stochastic processes (60-XX) 1 Functions of a complex variable (30-XX) 1 Potential theory (31-XX) 1 Ordinary differential equations (34-XX) 1 Partial differential equations (35-XX) 1 Geometry (51-XX) 1 General topology (54-XX) 1 Manifolds and cell complexes (57-XX) 1 Computer science (68-XX) 1 Mechanics of particles and systems (70-XX) 1 Quantum theory (81-XX) 1 Operations research, mathematical programming (90-XX)
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https://par.nsf.gov/biblio/10321811-first-discovery-new-pulsars-rrats-chime-frb
|
First Discovery of New Pulsars and RRATs with CHIME/FRB
Abstract We report the discovery of seven new Galactic pulsars with the Canadian Hydrogen Intensity Mapping Experiment’s Fast Radio Burst (CHIME/FRB) backend. These sources were first identified via single pulses in CHIME/FRB, then followed up with CHIME/Pulsar. Four sources appear to be rotating radio transients, pulsar-like sources with occasional single-pulse emission with an underlying periodicity. Of those four sources, three have detected periods ranging from 220 ms to 2.726 s. Three sources have more persistent but still intermittent emission and are likely intermittent or nulling pulsars. We have determined phase-coherent timing solutions for the latter two. These seven sources are the first discovery of previously unknown Galactic sources with CHIME/FRB and highlight the potential of fast radio burst detection instruments to search for intermittent Galactic radio sources.
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
Award ID(s):
Publication Date:
NSF-PAR ID:
10321811
Journal Name:
The Astrophysical Journal
Volume:
922
Issue:
1
ISSN:
0004-637X
National Science Foundation
##### More Like this
1. Abstract
The first fast radio burst (FRB) to be precisely localized was associated with a luminous persistent radio source (PRS). Recently, a second FRB/PRS association was discovered for another repeating source of FRBs. However, it is not clear what makes FRBs or PRS or how they are related. We compile FRB and PRS properties to consider the population of FRB/PRS sources. We suggest a practical definition for PRS as FRB associations with luminosity greater than 1029erg s−1Hz−1that are not attributed to star formation activity in the host galaxy. We model the probability distribution of the fraction of FRBs with PRS for repeaters and nonrepeaters, showing there is not yet evidence for repeaters to be preferentially associated with PRS. We discuss how FRB/PRS sources may be distinguished by the combination of active repetition and an excess dispersion measure local to the FRB environment. We use CHIME/FRB event statistics to bound the mean per-source repetition rate of FRBs to be between 25 and 440 yr−1. We use this to provide a bound on the density of FRB-emitting sources in the local universe of between 2.2 × 102and 5.2 × 104Gpc−3assuming a pulsar-like beamwidth for FRB emission. This density implies that PRS maymore »
2. Abstract
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a drift scan radio telescope operating across the 400–800 MHz band. CHIME is located at the Dominion Radio Astrophysical Observatory near Penticton, BC, Canada. The instrument is designed to map neutral hydrogen over the redshift range 0.8–2.5 to constrain the expansion history of the universe. This goal drives the design features of the instrument. CHIME consists of four parallel cylindrical reflectors, oriented north–south, each 100 m × 20 m and outfitted with a 256-element dual-polarization linear feed array. CHIME observes a two-degree-wide stripe covering the entire meridian at any given moment, observing three-quarters of the sky every day owing to Earth’s rotation. An FX correlator utilizes field-programmable gate arrays and graphics processing units to digitize and correlate the signals, with different correlation products generated for cosmological, fast radio burst, pulsar, very long baseline interferometry, and 21 cm absorber back ends. For the cosmology back end, the$Nfeed2$correlation matrix is formed for 1024 frequency channels across the band every 31 ms. A data receiver system applies calibration and flagging and, for our primary cosmological data product, stacks redundant baselines and integrates for 10 s. We present an overview of themore »
3. Abstract The Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB experiment has detected thousands of fast radio bursts (FRBs) due to its sensitivity and wide field of view; however, its low angular resolution prevents it from localizing events to their host galaxies. Very long baseline interferometry (VLBI), triggered by FRB detections from CHIME/FRB will solve the challenge of localization for non-repeating events. Using a refurbished 10 m radio dish at the Algonquin Radio Observatory located in Ontario Canada, we developed a testbed for a VLBI experiment with a theoretical λ / D ≲ 30 mas. We provide an overview of the 10 m system and describe its refurbishment, the data acquisition, and a procedure for fringe fitting that simultaneously estimates the geometric delay used for localization and the dispersive delay from the ionosphere. Using single pulses from the Crab pulsar, we validate the system and localization procedure, and analyze the clock stability between sites, which is critical for coherently delay referencing an FRB event. We find a localization of ∼200 mas is possible with the performance of the current system (single-baseline). Furthermore, for sources with insufficient signal or restricted wideband to simultaneously measure both geometric and ionospheric delays, we show that themore »
4. ABSTRACT
We present four new fast radio bursts discovered in a search of the Parkes 70-cm pulsar survey data archive for dispersed single pulses and bursts. We searched dispersion measures (DMs) ranging between 0 and 5000 pc cm−3 with the HEIMDALL and FETCH detection and classification algorithms. All four of the fast radio bursts (FRBs) discovered have significantly larger widths (>50 ms) than almost all of the FRBs detected and catalogued to date. The large pulse widths are not dominated by interstellar scattering or dispersive smearing within channels. One of the FRBs has a DM of 3338 pc cm3, the largest measured for any FRB to date. These are also the first FRBs detected by any radio telescope so far, predating the Lorimer Burst by almost a decade. Our results suggest that pulsar survey archives remain important sources of previously undetected FRBs and that searches for FRBs on time-scales extending beyond ∼100 ms may reveal the presence of a larger population of wide-pulse FRBs.
5. Abstract
We introduce a toy model for the time–frequency structure of fast radio bursts, in which the observed emission is produced as a narrowly peaked intrinsic spectral energy distribution sweeps down in frequency across the instrumental bandpass as a power law in time. Though originally motivated by emission models that invoke a relativistic shock, the model could in principle apply to a wider range of emission scenarios. We quantify the burst’s detectability using the frequency bandwidth over which most of its signal-to-noise ratio is accumulated. We demonstrate that, by varying just a single parameter of the toy model—the power-law indexβof the frequency drift rate—one can transform a long (and hence preferentially time-resolved) burst with a narrow time-integrated spectrum into a shorter burst with a broad power-law time-integrated spectrum. We suggest that source-to-source diversity in the value ofβcould generate the dichotomy between burst duration and frequency-bandwidth recently found by CHIME/FRB. In shock models, the value ofβis related to the radial density profile of the external medium, which, in light of the preferentially longer duration of bursts from repeating sources, may point to diversity in the external environments surrounding repeating versus one-off FRB sources.
| 2022-12-04T15:39:20 |
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https://par.nsf.gov/biblio/10304431-cumulants-correlation-functions-net-proton-proton-antiproton-multiplicity-distributions-au+au-collisions-energies-available-bnl-relativistic-heavy-ion-collider
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This content will become publicly available on August 1, 2022
Cumulants and correlation functions of net-proton, proton, and antiproton multiplicity distributions in $\mathrm{Au}+\mathrm{Au}$ collisions at energies available at the BNL Relativistic Heavy Ion Collider
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
Award ID(s):
Publication Date:
NSF-PAR ID:
10304431
Journal Name:
Physical Review C
Volume:
104
Issue:
2
ISSN:
2469-9985
| 2022-05-22T11:01:34 |
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http://www.itl.nist.gov/div898/handbook/apr/section2/apr223.htm
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8. Assessing Product Reliability
8.2. Assumptions/Prerequisites
8.2.2. How do you plot reliability data?
Trend and growth plotting (Duane plots)
Repair rates are typically either nearly constant over time or else consistently follow a good or a bad trend Models for repairable systems were described earlier. These models are for the cumulative number of failuress (or the repair rate) over time. The two models used with most success throughout industry are the HPP (constant repair rate or "exponential" system model) and the NHPP Power Law process (the repair rate is the polynomial $$m(t) = \alpha t^{-\beta}$$).
Before constructing a Duane Plot, there are a few simple trend plots that often convey strong evidence of the presence or absence of a trend in the repair rate over time. If there is no trend, an HPP model is reasonable. If there is an apparent improvement or degradation trend, a Duane Plot will provide a visual check for whether the NHPP Power law model is consistent with the data.
A few simple plots can help us decide whether trends are present These simple visual graphical tests for trends are
1. Plot cumulative failures versus system age (a step function that goes up every time there is a new failure). If this plot looks linear, there is no obvious improvement (or degradation) trend. A bending downward indicates improvement; bending upward indicates degradation.
2. Plot the inter arrival times between new failures (in other words, the waiting times between failures, with the time to the first failure used as the first "inter-arrival" time). If these trend up, there is improvement; if they trend down, there is degradation.
3. Plot the reciprocals of the inter-arrival times. Each reciprocal is a new failure rate estimate based only on the waiting time since the last failure. If these trend down, there is improvement; an upward trend indicates degradation.
Trend plots and a Duane Plot for actual Reliability Improvement Test data Case Study 1: Use of Trend Plots and Duane Plots with Reliability Improvement Test Data
A prototype of a new, complex piece of equipment went through a 1500 operational hours Reliability Improvement Test. During the test there were 10 failures. As part of the improvement process, a cross functional Failure Review Board made sure every failure was analyzed down to the root cause and design and parts selection fixes were implemented on the prototype. The observed failure times were: 5, 40, 43, 175, 389, 712, 747, 795, 1299 and 1478 hours, with the test ending at 1500 hours. The reliability engineer on the Failure Review Board first made trend plots as described above, then made a Duane plot. These plots follow.
Time Cum MTBF 5 5 40 20 43 14.3 175 43.75 389 77.8 712 118.67 747 106.7 795 99.4 1299 144.3 1478 147.8
Comments: The three trend plots all show an improvement trend. The reason it might be useful to try all three trend plots is that a trend might show up more clearly on one plot than the others. Formal statistical tests on the significance of this visual evidence of a trend will be shown in the section on Trend Tests.
The points on the Duane Plot line up roughly as a straight line, indicating the NHPP Power Law model is consistent with the data.
Estimates for the reliability growth slope and the MTBF at the end of this test for this case study will be given in a later section.
| 2017-10-18T16:53:35 |
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http://pdglive.lbl.gov/ConservationLaws.action?node=CD&name=CPT
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## $\mathit CPT$ INVARIANCE
$({\mathit m}_{{{\mathit W}^{+}}}–{\mathit m}_{{{\mathit W}^{-}}})/{\mathit m}_{\mathrm {average}}$ ($-3.7$ $\pm3.5$) $\times 10^{-4}$
$({\mathit m}_{{{\mathit e}^{+}}}–{\mathit m}_{{{\mathit e}^{-}}})/{\mathit m}_{\mathrm {average}}$ $<8 \times 10^{-9}$ CL=90.0%
$\vert \mathit q_{{{\mathit e}^{+}}}~+~\mathit q_{{{\mathit e}^{-}}}\vert /{{\mathit e}}$ $<4 \times 10^{-8}$
(${\mathit g}_{{{\mathit e}^{+}}}–{\mathit g}_{{{\mathit e}^{-}}}$) $/$ $\mathit g_{{\mathrm {average}}}$ ($-0.5$ $\pm2.1$) $\times 10^{-12}$
$({\mathit \tau}_{{{\mathit \mu}^{+}}}–{\mathit \tau}_{{{\mathit \mu}^{-}}})/{\mathit \tau}_{\mathrm {average}}$ ($2$ $\pm8$) $\times 10^{-5}$
$({\mathit g}_{{{\mathit \mu}^{+}}}–{\mathit g}_{{{\mathit \mu}^{-}}})/{\mathit g}_{average}$ ($-1.1$ $\pm1.2$) $\times 10^{-9}$
(${\mathit m}_{{{\mathit \tau}^{+}}}–{\mathit m}_{{{\mathit \tau}^{-}}})/\mathit m_{{\mathrm {average}}}$ $<2.8 \times 10^{-4}$ CL=90.0%
${\mathit m}_{{{\mathit t}}}$ $−$ ${\mathit m}_{{{\overline{\mathit t}}}}$ $-0.16$ $\pm0.19$ GeV
$({\mathit m}_{{{\mathit \pi}^{+}}}–{\mathit m}_{{{\mathit \pi}^{-}}})/{\mathit m}_{\mathrm {average}}$ ($2$ $\pm5$) $\times 10^{-4}$
$({\mathit \tau}_{{{\mathit \pi}^{+}}}–{\mathit \tau}_{{{\mathit \pi}^{-}}})/{\mathit \tau}_{\mathrm {average}}$ ($6$ $\pm7$) $\times 10^{-4}$
$({\mathit m}_{{{\mathit K}^{+}}}–{\mathit m}_{{{\mathit K}^{-}}})/{\mathit m}_{\mathrm {average}}$ ($-0.6$ $\pm1.8$) $\times 10^{-4}$
$({\mathit \tau}_{{{\mathit K}^{+}}}–{\mathit \tau}_{{{\mathit K}^{-}}})/{\mathit \tau}_{\mathrm {average}}$ $0.0010$ $\pm0.0009$ (S = 1.2)
${{\mathit K}^{\pm}}$ $\rightarrow$ ${{\mathit \mu}^{\pm}}{{\mathit \nu}_{{\mu}}}$ rate difference/sum $-0.0027$ $\pm0.0021$
${{\mathit K}^{\pm}}$ $\rightarrow$ ${{\mathit \pi}^{\pm}}{{\mathit \pi}^{0}}$ rate difference/sum [1] $0.004$ $\pm0.006$
${{\mathit \delta}}$ in ${{\mathit K}^{0}}\text{-}{{\overline{\mathit K}}^{0}}$ mixing
real part of $\delta$ ($2.5$ $\pm2.3$) $\times 10^{-4}$
imaginary part of $\delta$ ($-1.5$ $\pm1.6$) $\times 10^{-5}$
Re(y), ${{\mathit K}_{{{e3}}}}$ parameter $0.0004$ $\pm0.0025$
Re(x$_{-}$), ${{\mathit K}_{{e3}}}$ parameter $-0.0029$ $\pm0.0020$
$\vert{}{\mathit m}_{{{\mathit K}^{0}}}–{\mathit m}_{{{\overline{\mathit K}}^{0}}}\vert{}/{\mathit m}_{\mathrm {average}}$ [2] $<6 \times 10^{-19}$ CL=90.0%
(${\Gamma}_{{\mathit K}^{0}}−{\Gamma}_{{\overline{\mathit K}}^{0}})/{\mathit m}_{{\mathrm {average}}}$ ($8$ $\pm8$) $\times 10^{-18}$
phase difference $\phi _{00}$ $−$ $\phi _{+−}$ $0.34$ $\pm0.32$ $^\circ{}$
Re(${2\over 3}\eta _{+−}$ $+$ ${1\over 3}\eta _{00})−{\mathit A_{L}\over 2}$ ($-0.3$ $\pm3.5$) $\times 10^{-5}$
$\mathit A_{CPT}$( ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit K}^{-}}{{\mathit \pi}^{+}}$ ) $0.008$ $\pm0.008$
$\Delta {{\mathit S}_{{CPT}}^{+}}$ (S${}^{-}_{{{\mathit \ell}}{}^{+},{{\mathit K}_S^0} }$ $−$ S${}^{+}_{{{\mathit \ell}}{}^{+},{{\mathit K}_S^0} }$) $0.16$ $\pm0.23$
$\Delta {{\mathit S}_{{CPT}}^{-}}$ (S${}^{+}_{{{\mathit \ell}}{}^{+},{{\mathit K}_S^0} }$ $−$ S${}^{-}_{{{\mathit \ell}}{}^{+},{{\mathit K}_S^0} }$) $-0.03$ $\pm0.14$
$\Delta {{\mathit C}_{{CPT}}^{+}}$ (C${}^{-}_{{{\mathit \ell}}{}^{+},{{\mathit K}_S^0} }$ $−$ C${}^{+}_{{{\mathit \ell}}{}^{+},{{\mathit K}_S^0} }$) $0.14$ $\pm0.17$
$\Delta {{\mathit C}_{{CPT}}^{-}}$ (C${}^{+}_{{{\mathit \ell}}{}^{+},{{\mathit K}_S^0} }$ $−$ C${}^{-}_{{{\mathit \ell}}{}^{+},{{\mathit K}_S^0} }$) $0.03$ $\pm0.14$
$\vert {\mathit m}_{{{\mathit p}}}−{\mathit m}_{{{\overline{\mathit p}}}}\vert /{\mathit m}_{{{\mathit p}}}$ [3] $<7 \times 10^{-10}$ CL=90.0%
($\vert {\mathit q_{{{\overline{\mathit p}}}}\over {\mathit m}_{{{\overline{\mathit p}}}}}\vert -{\mathit q_{p}\over {\mathit m}_{{{\mathit p}}}})/{\mathit q_{{{\mathit p}}}\over {\mathit m}_{{{\mathit p}}}}$ ($-9$ $\pm9$) $\times 10^{-11}$
$\vert \mathit q_{{{\mathit p}}}~+~\mathit q_{{{\overline{\mathit p}}}}\vert /{{\mathit e}}$ [3] $<7 \times 10^{-10}$ CL=90.0%
(${\mathit \mu}_{{{\mathit p}}}$ $+$ ${\mathit \mu}_{{{\overline{\mathit p}}}}$) $/$ $\mu _{{{\mathit p}}}$ ($3$ $\pm8$) $\times 10^{-7}$
(${\mathit m}_{{{\mathit n}}}–{\mathit m}_{{{\overline{\mathit n}}}}$ )/ ${\mathit m}_{{{\mathit n}}}$ ($9$ $\pm6$) $\times 10^{-5}$
(${\mathit m}_{{{\mathit \Lambda}}}–{\mathit m}_{{{\overline{\mathit \Lambda}}}}$) $/$ ${\mathit m}_{{{\mathit \Lambda}}}$ ($-0.1$ $\pm1.1$) $\times 10^{-5}$ (S = 1.6)
(${\mathit \tau}_{{{\mathit \Lambda}}}–{\mathit \tau}_{{{\overline{\mathit \Lambda}}}}$) $/$ ${\mathit \tau}_{{{\mathit \Lambda}}}$ $-0.001$ $\pm0.009$
(${\mathit \tau}_{{{\mathit \Sigma}^{+}}}–{\mathit \tau}_{{{\overline{\mathit \Sigma}}^{-}}}$) $/$ ${\mathit \tau}_{{{\mathit \Sigma}^{+}}}$ $-0.0006$ $\pm0.0012$
(${\mathit \mu}_{{{\mathit \Sigma}^{+}}}$ $+$ ${\mathit \mu}_{{{\overline{\mathit \Sigma}}^{-}}}$) $/$ ${\mathit \mu}_{{{\mathit \Sigma}^{+}}}$ $0.014$ $\pm0.015$
(${\mathit m}_{{{\mathit \Xi}^{-}}}–{\mathit m}_{{{\overline{\mathit \Xi}}^{+}}}$) $/$ ${\mathit m}_{{{\mathit \Xi}^{-}}}$ ($-3$ $\pm9$) $\times 10^{-5}$
(${\mathit \tau}_{{{\mathit \Xi}^{-}}}–{\mathit \tau}_{{{\overline{\mathit \Xi}}^{+}}}$) $/$ ${\mathit \tau}_{{{\mathit \Xi}^{-}}}$ $-0.01$ $\pm0.07$
(${\mathit \mu}_{{{\mathit \Xi}^{-}}}$ + ${\mathit \mu}_{{{\overline{\mathit \Xi}}^{+}}}$) $/$ $\vert {\mathit \mu}_{{{\mathit \Xi}^{-}}}\vert$ $+0.01$ $\pm0.05$
(${\mathit m}_{{{\mathit \Omega}^{-}}}–{\mathit m}_{{{\overline{\mathit \Omega}}^{+}}}$) $/$ ${\mathit m}_{{{\mathit \Omega}^{-}}}$ ($-1$ $\pm8$) $\times 10^{-5}$
(${\mathit \tau}_{{{\mathit \Omega}^{-}}}–{\mathit \tau}_{{{\overline{\mathit \Omega}}^{+}}}$) $/$ ${\mathit \tau}_{{{\mathit \Omega}^{-}}}$ $0.00$ $\pm0.05$
[1] Neglecting photon channels. See, $\mathit e.g.$, A. Pais and S.B. Treiman, Phys. Rev. $\mathbf {D12}$, 2744 (1975).
[2] Derived from measured values of $\phi _{+−}$, $\phi _{{\mathrm {00}}}$, $\vert \eta \vert$, $\vert{}{\mathit m}_{{{\mathit K}_L^0} }–{\mathit m}_{{{\mathit K}_S^0} }\vert{}$, and ${\mathit \tau}_{{{\mathit K}_S^0} }$, as described in the introduction to Tests of Conservation Laws.''
[3] The $\vert {\mathit m}_{{{\mathit p}}}−{\mathit m}_{{{\overline{\mathit p}}}}\vert /{\mathit m}_{{{\mathit p}}}$ and $\vert {{\mathit q}_{{p}}}$ + ${{\mathit q}}_{{{\overline{\mathit p}}}}\vert /{{\mathit e}}$ are not independent, and both use the more precise measurement of $\vert \mathit q_{{{\overline{\mathit p}}}}/{\mathit m}_{{{\overline{\mathit p}}}}\vert /(\mathit q_{{{\mathit p}}}/{\mathit m}_{{{\mathit p}}}$).
| 2019-04-19T08:57:50 |
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http://dlmf.nist.gov/22.1
|
# §22.1 Special Notation
(For other notation see Notation for the Special Functions.)
$x,y$ real variables. complex variable. modulus. Except in §§22.3(iv), 22.17, and 22.19, $0\leq k\leq 1$. complementary modulus, $k^{2}+{k^{\prime}}^{2}=1$. If $k\in[0,1]$, then $k^{\prime}\in[0,1]$. $\mathop{K\/}\nolimits\!\left(k\right)$, $\mathop{{K^{\prime}}\/}\nolimits\!\left(k\right)=\mathop{K\/}\nolimits\!\left(% k^{\prime}\right)$ (complete elliptic integrals of the first kind (§19.2(ii))). nome. $0\leq q<1$ except in §22.17; see also §20.1. $i\mathop{{K^{\prime}}\/}\nolimits/\mathop{K\/}\nolimits$.
All derivatives are denoted by differentials, not primes.
The functions treated in this chapter are the three principal Jacobian elliptic functions $\mathop{\mathrm{sn}\/}\nolimits\left(z,k\right)$, $\mathop{\mathrm{cn}\/}\nolimits\left(z,k\right)$, $\mathop{\mathrm{dn}\/}\nolimits\left(z,k\right)$; the nine subsidiary Jacobian elliptic functions $\mathop{\mathrm{cd}\/}\nolimits\left(z,k\right)$, $\mathop{\mathrm{sd}\/}\nolimits\left(z,k\right)$, $\mathop{\mathrm{nd}\/}\nolimits\left(z,k\right)$, $\mathop{\mathrm{dc}\/}\nolimits\left(z,k\right)$, $\mathop{\mathrm{nc}\/}\nolimits\left(z,k\right)$, $\mathop{\mathrm{sc}\/}\nolimits\left(z,k\right)$, $\mathop{\mathrm{ns}\/}\nolimits\left(z,k\right)$, $\mathop{\mathrm{ds}\/}\nolimits\left(z,k\right)$, $\mathop{\mathrm{cs}\/}\nolimits\left(z,k\right)$; the amplitude function $\mathop{\mathrm{am}\/}\nolimits\left(x,k\right)$; Jacobi’s epsilon and zeta functions $\mathop{\mathcal{E}\/}\nolimits\!\left(x,k\right)$ and $\mathop{\mathrm{Z}\/}\nolimits\!\left(x|k\right)$.
The notation $\mathop{\mathrm{sn}\/}\nolimits\left(z,k\right)$, $\mathop{\mathrm{cn}\/}\nolimits\left(z,k\right)$, $\mathop{\mathrm{dn}\/}\nolimits\left(z,k\right)$ is due to Gudermann (1838), following Jacobi (1827); that for the subsidiary functions is due to Glaisher (1882). Other notations for $\mathop{\mathrm{sn}\/}\nolimits\left(z,k\right)$ are $\mathrm{sn}(z\mathpunct{|}m)$ and $\mathrm{sn}(z,m)$ with $m=k^{2}$; see Abramowitz and Stegun (1964) and Walker (1996). Similarly for the other functions.
| 2017-05-25T20:12:56 |
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https://zbmath.org/authors/?q=ai%3Adey.dipak-k
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zbMATH — the first resource for mathematics
Dey, Dipak Kumar
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Author ID: dey.dipak-k Published as: Dey, Dipak K.; Dey, D. K.; Dey, Dipak; Dey, Dipak Kumar; Dey, Dipak. K. Homepage: https://stat.uconn.edu/dipak-dey/ External Links: MGP · ORCID · Wikidata · Google Scholar · dblp · GND · IdRef
Documents Indexed: 203 Publications since 1972, including 11 Books
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Citations contained in zbMATH Open
134 Publications have been cited 1,657 times in 1,275 Documents Cited by Year
A general class of multivariate skew-elliptical distributions. Zbl 0992.62047
Branco, Márcia D.; Dey, Dipak K.
2001
Bayesian model choice: Asymptotics and exact calculations. Zbl 0800.62170
Gelfand, A. E.; Dey, D. K.
1994
A new class of multivariate skew distributions with applications to Bayesian regression models. Zbl 1039.62047
Sahu, Sujit K.; Dey, Dipak K.; Branco, Márcia D.
2003
Estimation of a covariance matrix under Stein’s loss. Zbl 0582.62042
Dey, Dipak K.; Srinivasan, C.
1985
Bayesian analysis of outlier problems using divergence measures. Zbl 0833.62028
Peng, Fengchun; Dey, Dipak K.
1995
Semiparametric Bayesian analysis of survival data. Zbl 1067.62520
Sinha, Debajyoti; Dey, Dipak K.
1997
Bayesian approach for nonlinear random effects models. Zbl 0911.62024
Dey, Dipak K.; Chen, Ming-Hui; Chang, Hong
1997
A new skewed link model for dichotomous quantal response data. Zbl 1072.62655
Chen, Ming-Hui; Dey, Dipak K.; Shao, Qi-Man
1999
Practical nonparametric and semiparametric Bayesian statistics. Zbl 0893.00018
Dey, Dipak (ed.); Müller, Peter (ed.); Sinha, Debajyoti (ed.)
1998
Frequentist validity of posterior quantiles in the presence of a nuisance parameter: Higher order asymptotics. Zbl 0788.62025
Mukerjee, Rahul; Dey, Dipak K.
1993
Flexible generalized $$t$$-link models for binary response data. Zbl 1437.62513
Kim, Sungduk; Chen, Ming-Hui; Dey, Dipak K.
2008
On estimation with balanced loss functions. Zbl 0951.62019
Dey, Dipak K.; Ghosh, Malay; Strawderman, William E.
1999
A Weibull regression model with gamma frailties for multivariate survival data. Zbl 0896.62125
Sahu, Sujit K.; Dey, Dipak K.; Aslanidou, Helen; Sinha, Debajyoti
1997
Improved estimation of the disturbance variance in a linear regression model. Zbl 0677.62060
Gelfand, Alan E.; Dey, Dipak K.
1988
Generalized extreme value regression for binary response data: an application to B2B electronic payments system adoption. Zbl 1220.62165
Wang, Xia; Dey, Dipak K.
2010
Generalized linear models. A Bayesian perspective. Zbl 1006.00009
Dey, Dipak K. (ed.); Ghosh, Sujit K. (ed.); Mallick, Bani K. (ed.)
2000
Robust Bayesian analysis using divergence measures. Zbl 0799.62003
Dey, Dipak K.; Birmiwal, Lea R.
1994
Simultaneous estimation of parameters under entropy loss. Zbl 0609.62009
Dey, Dipak K.; Ghosh, Malay; Srinivasan, C.
1987
A simulation-intensive approach for checking hierarchical models. Zbl 0935.62082
Dey, Dipak K.; Gelfand, Alan E.; Swartz, Tim B.; Vlachos, Pantelis K.
1998
Bayesian modeling of correlated binary responses via scale mixture of multivariate normal link functions. Zbl 0976.62019
Chen, Ming-Hui; Dey, Dipak K.
1998
Robust linear mixed models with skew-normal independent distributions from a Bayesian perspective. Zbl 1183.62048
Lachos, Victor H.; Dey, Dipak K.; Cancho, Vicente G.
2009
Overdispersed generalized linear models. Zbl 0890.62054
Dey, Dipak K.; Gelfand, Alan E.; Peng, Fengchun
1997
Bayesian analysis of multivariate survival data using Monte Carlo methods. Zbl 0910.62023
Aslanidou, Helen; Dey, Dipak K.; Sinha, Debajyoti
1998
Complex elliptical distributions with application to shape analysis. Zbl 1094.62062
Micheas, Athanasios C.; Dey, Dipak K.; Mardia, Kanti V.
2006
Bayesian dynamic models for survival data with a cure fraction. Zbl 1121.62029
Kim, Sungduk; Chen, Ming-Hui; Dey, Dipak K.; Gamerman, Dani
2007
Bayesian nonlinear regression models with scale mixtures of skew-normal distributions: estimation and case influence diagnostics. Zbl 1247.62083
Cancho, Vicente G.; Dey, Dipak K.; Lachos, Victor H.; Andrade, Marinho G.
2011
Simultaneous estimation of eigenvalues. Zbl 0669.62034
Dey, Dipak K.
1988
A comparison of frailty and other models for bivariate survival data. Zbl 0966.62086
Sahu, Sujit K.; Dey, Dipak K.
2000
Semiparametric proportional odds models for spatially correlated survival data. Zbl 1080.62085
Banerjee, Sudipto; Dey, Dipak K.
2005
Bayesian analysis of generalized odds-rate hazards models for survival data. Zbl 1162.62430
Banerjee, Tathagata; Chen, Ming-Hui; Dey, Dipak K.; Kim, Sungduk
2007
On truncation of shrinkage estimators in simultaneous estimation of normal means. Zbl 0536.62039
Dey, Dipak K.; Berger, James O.
1983
Multivariate survival analysis with positive stable frailties. Zbl 1059.62688
Qiou, Zuqiang; Ravishanker, Nalini; Dey, Dipak K.
1999
Linear and nonlinear mixed-effects models for censored HIV viral loads using normal/independent distributions. Zbl 1274.62806
Lachos, Victor H.; Bandyopadhyay, Dipankar; Dey, Dipak K.
2011
A multivariate mixture of Weibull distributions in reliability modeling. Zbl 1055.62554
Patra, Kaushik; Dey, Dipak K.
1999
On Bayesian robustness of contaminated classes of priors. Zbl 0749.62007
Gelfand, A. E.; Dey, D. K.
1991
On the estimation of a variance ratio. Zbl 0664.62021
Gelfand, Alan E.; Dey, Dipak K.
1988
Trimmed minimax estimator of a covariance matrix. Zbl 0591.62048
Dey, Dipak K.; Srinivasan, C.
1986
Bayesian analysis for correlated ordinal data models. Zbl 1022.62030
Chen, Ming-Hui; Dey, Dipak K.
2000
Modeling shape distributions and inferences for assessing differences in shapes. Zbl 1063.60016
Micheas, Athanasios C.; Dey, Dipak K.
2005
Bayesian criterion based model assessment for categorical data. Zbl 1132.62301
Chen, Ming-Hui; Dey, Dipak K.; Ibrahim, Joseph G.
2004
A new threshold regression model for survival data with a cure fraction. Zbl 1322.62281
Kim, Sungduk; Chen, Ming-Hui; Dey, Dipak K.
2011
On estimation of discriminant coefficients. Zbl 0716.62058
Dey, Dipak K.; Srinivasan, C.
1991
A first course in linear model theory. Zbl 1015.62067
Ravishanker, Nalini; Dey, Dipak K.
2002
A new class of flexible link functions with application to species co-occurrence in Cape Floristic region. Zbl 1283.62228
Jiang, Xun; Dey, Dipak K.; Prunier, Rachel; Wilson, Adam M.; Holsinger, Kent E.
2013
Bayesian and frequentist estimation and prediction for exponential distributions. Zbl 1094.62036
Ren, Cuirong; Sun, Dongchu; Dey, Dipak K.
2006
On Bayesian inference for generalized multivariate gamma distribution. Zbl 1201.62008
Das, Sourish; Dey, Dipak K.
2010
On the admissibility of the linear estimators of the Poisson mean using Linex loss functions. Zbl 0716.62008
Kuo, L.; Dey, D. K.
1990
Improved estimation of a multinormal precision matrix. Zbl 0628.62056
Dey, Dipak K.
1987
Skew-normal/independent linear mixed models for censored responses with applications to HIV viral loads. Zbl 1244.62076
Bandyopadhyay, Dipankar; Lachos, Victor H.; Castro, Luis M.; Dey, Dipak K.
2012
Combining coordinates in simultaneous estimation of normal means. Zbl 0527.62036
Berger, James O.; Dey, Dipak K.
1983
Bayesian inference in nonlinear mixed-effects models using normal independent distributions. Zbl 1468.62109
Lachos, Victor H.; Castro, Luis M.; Dey, Dipak K.
2013
Properties of a multivariate survival distribution generated by a Weibull and inverse-Gaussian mixture. Zbl 0799.60086
Jaisingh, Lloyd R.; Dey, Dipak. K.; Griffith, William S.
1993
Bayesian robustness for multiparameter problems. Zbl 0798.62007
1994
Propriety of posterior distributions arising in categorical and survival models under generalized extreme value distribution. Zbl 1285.62055
Roy, Vivekananda; Dey, Dipak K.
2014
Fully semiparametric Bayesian approach for modeling survival data with cure fraction. Zbl 1441.62322
Demarqui, Fabio N.; Dey, Dipak K.; Loschi, Rosangela H.; Colosimo, Enrico A.
2014
Modeling expert opinion arising as a partial probabilistic specification. Zbl 0826.62007
Gelfand, Alan E.; Mallick, Bani K.; Dey, Dipak K.
1995
Multitude of multivariate $$t$$-distributions. Zbl 1067.62059
2005
Regression model under skew elliptical error distribution. Zbl 1076.62056
Branco, Márcia D.; Dey, Dipak K.
2002
Ranges of posterior expected losses and $$\epsilon$$-robust actions. Zbl 1281.62077
Dey, Dipak K.; Micheas, Athanasios C.
2000
Modeling publication bias using weighted distributions in a Bayesian framework. Zbl 1042.62525
Larose, Daniel T.; Dey, Dipak K.
1998
Bayesian approach to estimation of intraclass correlation using reference prior. Zbl 0917.62019
Chung, Younshik; Dey, Dipak K.
1998
Compund Poisson distributions: Properties and estimation. Zbl 0774.62026
Dey, Dipak K.; Chung, Younshik
1992
Estimation of scale parameters in mixture distributions. Zbl 0702.62046
Dey, Dipak K.
1990
Test to distinguish a Brownian motion from a Brownian bridge using Pólya tree process. Zbl 1209.62099
Bharath, Karthik; Dey, Dipak K.
2011
A class of dynamic piecewise exponential models with random time grid. Zbl 1227.62083
Demarqui, Fabio N.; Loschi, Rosangela H.; Dey, Dipak K.; Colosimo, Enrico A.
2012
A unified Bayesian approach for analyzing correlated ordinal response data. Zbl 0966.62045
Chen, Ming-Hui; Dey, Dipak K.
2000
A new class of improved estimators of a multinormal precision matrix. Zbl 0716.62054
Dey, D. K.; Ghosh, M.; Srinivasan, C.
1990
Prior and posterior predictive p-values in the one-sided location parameter testing problem. Zbl 1192.62088
Micheas, Athanasios C.; Dey, Dipak K.
2003
On dynamic generalized linear models with applications. Zbl 1308.62045
Das, Sourish; Dey, Dipak K.
2013
A quantitative study of quantile based direct prior elicitation from expert opinion. Zbl 1331.62029
Dey, Dipak K.; Liu, Junfeng
2007
A Bayesian approach using nonhomogeneous Poisson processes for software reliability models. Zbl 0936.62110
Achcar, J. A.; Dey, D. K.; Niverthi, M.
1998
On estimation of the scale matrix of the multivariate F distribution. Zbl 0696.62101
Dey, Dipak K.
1989
A new class of minimax estimators of multivariate normal mean vectors under balanced loss function. Zbl 1054.62508
Chung, Younshik; Kim, Chansoo; Dey, Dipak K.
1999
Weighted distributions viewed in the context of model selection: A Bayesian perspective. Zbl 0852.62030
Larose, D. T.; Dey, D. K.
1996
A Bayesian approach to loss robustness. Zbl 0922.62014
Dey, Dipak K.; Lou, Kuo-ren; Bose, Sudip
1998
Bayesian approach to change point problems. Zbl 0954.62526
Dey, Dipak K.; Purkayastha, Sumitra
1997
Convolutions of the $$t$$ distribution. Zbl 1137.62307
2005
On measuring loss robustness using maximum a posteriori estimate. Zbl 1114.62322
Micheas, Athanasios C.; Dey, Dipak K.
2004
Variable selection for multivariate logistic regression models. Zbl 1027.62015
Chen, Ming-Hui; Dey, Dipak K.
2003
Long-term survival models with latent activation under a flexible family of distributions. Zbl 1298.62165
Cancho, Vicente G.; de Castro, Mário; Dey, Dipak K.
2013
A flexible cure rate model for spatially correlated survival data based on generalized extreme value distribution and Gaussian process priors. Zbl 1358.62098
Li, Dan; Wang, Xia; Dey, Dipak K.
2016
On the choice of coordinates in simultaneous estimation of normal means under misspecification of normal priors. Zbl 0513.62037
Dey, Dipak K.
1983
Trimmed estimates in simultaneous estimation of parameters in exponential families. Zbl 0543.62003
Ghosh, Malay; Dey, Dipak K.
1984
Improved estimation of variance components in mixed models. Zbl 0696.62298
Gelfand, Alan E.; Dey, Dipak K.
1988
Improved estimation of the common scale parameter of several Pareto distributions. Zbl 0769.62020
Dey, Dipak K.; Liu, Pei-San Liao
1992
Bayesian thinking, modeling and computation. Zbl 1136.62012
Dey, Dipak (ed.); Rao, C. R. (ed.)
2005
Model determination for the variance component model using reference priors. Zbl 1023.62028
Chung, Younshik; Dey, Dipak K.
2002
A new empirical Bayes estimator with type II censored data. Zbl 0825.62340
Dey, D. K.; Kuo, L.
1991
Multivariate survival models with a mixture of positive stable frailties. Zbl 0971.62062
Ravishanker, Nalini; Dey, Dipak K.
2000
Multivariate process capability. A Bayesian perspective. Zbl 0968.62560
Niverthi, Murali; Dey, Dipak K.
2000
A new construction for skew multivariate distributions. Zbl 1076.62051
Dey, Dipak K.; Liu, Junfeng
2005
A general class of change point and change curve models for life time data. Zbl 1015.62102
Patra, Kaushik; Dey, Dipak K.
2002
Modelling accelerated life test data by using a Bayesian approach. Zbl 1111.62327
Sinha, Debajyoti; Patra, Kauhsik; Dey, Dipak K.
2003
Intervention analysis of hurricane effects on snail abundance in a tropical forest using long-term spatiotemporal data. Zbl 1306.62323
Prates, Marcos O.; Dey, Dipak K.; Willig, Michael R.; Yan, Jun
2011
Reconciling Bayesian and frequentist evidence in the one-sided scale parameter testing problem. Zbl 1115.62031
Micheas, Athanasios C.; Dey, Dipak K.
2007
Comparison of Bayesian and frequentist estimation and prediction for a normal population. Zbl 1192.62091
Ren, Cuirong; Sun, Dongchu; Dey, Dipak K.
2004
Bayesian estimation of a skew-Student-$$t$$ stochastic volatility model. Zbl 1327.62128
Abanto-Valle, C. A.; Lachos, V. H.; Dey, Dipak K.
2015
Modeling multilevel survival data using frailty models. Zbl 1140.62079
Kim, Sungduk; Dey, Dipak K.
2008
Erratum: A new class of multivariate skew distributions with applications to Bayesian regression models. Zbl 1175.62049
Sahu, Sujit K.; Dey, Dipak K.; Branco, Márcia D.
2009
Bayesian isotonic changepoint analysis. Zbl 1332.62085
Alvarez, Enrique E.; Dey, Dipak K.
2009
Flexible regression modeling for censored data based on mixtures of Student-$$t$$ distributions. Zbl 1417.62280
Lachos, Víctor H.; Cabral, Celso R. B.; Prates, Marcos O.; Dey, Dipak K.
2019
Leveraging mixed and incomplete outcomes via reduced-rank modeling. Zbl 1395.62135
Luo, Chongliang; Liang, Jian; Li, Gen; Wang, Fei; Zhang, Changshui; Dey, Dipak K.; Chen, Kun
2018
Bayesian sparse reduced rank multivariate regression. Zbl 1362.62140
Goh, Gyuhyeong; Dey, Dipak K.; Chen, Kun
2017
A flexible cure rate model for spatially correlated survival data based on generalized extreme value distribution and Gaussian process priors. Zbl 1358.62098
Li, Dan; Wang, Xia; Dey, Dipak K.
2016
Bayesian estimation of a skew-Student-$$t$$ stochastic volatility model. Zbl 1327.62128
Abanto-Valle, C. A.; Lachos, V. H.; Dey, Dipak K.
2015
Bayesian Markov chain random field cosimulation for improving land cover classification accuracy. Zbl 1323.86025
Li, Weidong; Zhang, Chuanrong; Willig, Michael R.; Dey, Dipak K.; Wang, Guiling; You, Liangzhi
2015
Propriety of posterior distributions arising in categorical and survival models under generalized extreme value distribution. Zbl 1285.62055
Roy, Vivekananda; Dey, Dipak K.
2014
Fully semiparametric Bayesian approach for modeling survival data with cure fraction. Zbl 1441.62322
Demarqui, Fabio N.; Dey, Dipak K.; Loschi, Rosangela H.; Colosimo, Enrico A.
2014
Bayesian model diagnostics using functional Bregman divergence. Zbl 1359.62083
Goh, Gyuhyeong; Dey, Dipak K.
2014
State space mixed models for binary responses with scale mixture of normal distributions links. Zbl 06975388
Abanto-Valle, Carlos A.; Dey, Dipak K.
2014
Asymptotics of the empirical cross-over function. Zbl 1334.62089
Bharath, Karthik; Pozdnyakov, Vladimir; Dey, Dipak K.
2014
A new class of flexible link functions with application to species co-occurrence in Cape Floristic region. Zbl 1283.62228
Jiang, Xun; Dey, Dipak K.; Prunier, Rachel; Wilson, Adam M.; Holsinger, Kent E.
2013
Bayesian inference in nonlinear mixed-effects models using normal independent distributions. Zbl 1468.62109
Lachos, Victor H.; Castro, Luis M.; Dey, Dipak K.
2013
On dynamic generalized linear models with applications. Zbl 1308.62045
Das, Sourish; Dey, Dipak K.
2013
Long-term survival models with latent activation under a flexible family of distributions. Zbl 1298.62165
Cancho, Vicente G.; de Castro, Mário; Dey, Dipak K.
2013
Asymptotics of a clustering criterion for smooth distributions. Zbl 1336.62172
Bharath, Karthik; Pozdnyakov, Vladimir; Dey, Dipak K.
2013
Skew-normal/independent linear mixed models for censored responses with applications to HIV viral loads. Zbl 1244.62076
Bandyopadhyay, Dipankar; Lachos, Victor H.; Castro, Luis M.; Dey, Dipak K.
2012
A class of dynamic piecewise exponential models with random time grid. Zbl 1227.62083
Demarqui, Fabio N.; Loschi, Rosangela H.; Dey, Dipak K.; Colosimo, Enrico A.
2012
A dengue fever study in the state of Rio de Janeiro with the use of generalized skew-normal/independent spatial fields. Zbl 1449.62251
Prates, Marcos Oliveira; Dey, Dipak Kumar; Lachos, Victor Hugo
2012
Bayesian modeling of bathtub shaped hazard rate using various Weibull extensions and related issues of model selection. Zbl 1257.62030
Upadhyay, S. K.; Gupta, Ashutosh; Dey, Dipak K.
2012
Bayesian nonlinear regression models with scale mixtures of skew-normal distributions: estimation and case influence diagnostics. Zbl 1247.62083
Cancho, Vicente G.; Dey, Dipak K.; Lachos, Victor H.; Andrade, Marinho G.
2011
Linear and nonlinear mixed-effects models for censored HIV viral loads using normal/independent distributions. Zbl 1274.62806
Lachos, Victor H.; Bandyopadhyay, Dipankar; Dey, Dipak K.
2011
A new threshold regression model for survival data with a cure fraction. Zbl 1322.62281
Kim, Sungduk; Chen, Ming-Hui; Dey, Dipak K.
2011
Test to distinguish a Brownian motion from a Brownian bridge using Pólya tree process. Zbl 1209.62099
Bharath, Karthik; Dey, Dipak K.
2011
Intervention analysis of hurricane effects on snail abundance in a tropical forest using long-term spatiotemporal data. Zbl 1306.62323
Prates, Marcos O.; Dey, Dipak K.; Willig, Michael R.; Yan, Jun
2011
Generalized extreme value regression for binary response data: an application to B2B electronic payments system adoption. Zbl 1220.62165
Wang, Xia; Dey, Dipak K.
2010
On Bayesian inference for generalized multivariate gamma distribution. Zbl 1201.62008
Das, Sourish; Dey, Dipak K.
2010
Frontiers of statistical decision making and Bayesian analysis. In honor of James O. Berger. Zbl 1197.62006
Chen, Ming-Hui; Dey, Dipak K.; Müller, Peter; Sun, Dongchu; Ye, Keying
2010
Robust linear mixed models with skew-normal independent distributions from a Bayesian perspective. Zbl 1183.62048
Lachos, Victor H.; Dey, Dipak K.; Cancho, Vicente G.
2009
Erratum: A new class of multivariate skew distributions with applications to Bayesian regression models. Zbl 1175.62049
Sahu, Sujit K.; Dey, Dipak K.; Branco, Márcia D.
2009
Bayesian isotonic changepoint analysis. Zbl 1332.62085
Alvarez, Enrique E.; Dey, Dipak K.
2009
Flexible generalized $$t$$-link models for binary response data. Zbl 1437.62513
Kim, Sungduk; Chen, Ming-Hui; Dey, Dipak K.
2008
Modeling multilevel survival data using frailty models. Zbl 1140.62079
Kim, Sungduk; Dey, Dipak K.
2008
Skew random effects in multilevel binomial models: an alternative to nonparametric approach. Zbl 07257869
Liu, Junfeng; Dey, Dipak K.
2008
Bayesian dynamic models for survival data with a cure fraction. Zbl 1121.62029
Kim, Sungduk; Chen, Ming-Hui; Dey, Dipak K.; Gamerman, Dani
2007
Bayesian analysis of generalized odds-rate hazards models for survival data. Zbl 1162.62430
Banerjee, Tathagata; Chen, Ming-Hui; Dey, Dipak K.; Kim, Sungduk
2007
A quantitative study of quantile based direct prior elicitation from expert opinion. Zbl 1331.62029
Dey, Dipak K.; Liu, Junfeng
2007
Reconciling Bayesian and frequentist evidence in the one-sided scale parameter testing problem. Zbl 1115.62031
Micheas, Athanasios C.; Dey, Dipak K.
2007
Bayesian estimation of stochastic frontier models with multivariate skew $$t$$ error terms. Zbl 1115.62033
Tchumtchoua, Sylvie; Dey, Dipak K.
2007
Complex elliptical distributions with application to shape analysis. Zbl 1094.62062
Micheas, Athanasios C.; Dey, Dipak K.; Mardia, Kanti V.
2006
Bayesian and frequentist estimation and prediction for exponential distributions. Zbl 1094.62036
Ren, Cuirong; Sun, Dongchu; Dey, Dipak K.
2006
On the product and ratio of $$t$$ random variables. Zbl 1082.60009
2006
Semiparametric proportional odds models for spatially correlated survival data. Zbl 1080.62085
Banerjee, Sudipto; Dey, Dipak K.
2005
Modeling shape distributions and inferences for assessing differences in shapes. Zbl 1063.60016
Micheas, Athanasios C.; Dey, Dipak K.
2005
Multitude of multivariate $$t$$-distributions. Zbl 1067.62059
2005
Convolutions of the $$t$$ distribution. Zbl 1137.62307
2005
Bayesian thinking, modeling and computation. Zbl 1136.62012
Dey, Dipak; Rao, C. R.
2005
A new construction for skew multivariate distributions. Zbl 1076.62051
Dey, Dipak K.; Liu, Junfeng
2005
Convolutions of the Pearson type VII distribution. Zbl 1101.62009
2005
Assessing shape differences in populations of shapes using the complex Watson shape distribution. Zbl 1121.62440
Micheas, Athanasios C.; Dey, Dipak K.
2005
Bayesian criterion based model assessment for categorical data. Zbl 1132.62301
Chen, Ming-Hui; Dey, Dipak K.; Ibrahim, Joseph G.
2004
On measuring loss robustness using maximum a posteriori estimate. Zbl 1114.62322
Micheas, Athanasios C.; Dey, Dipak K.
2004
Comparison of Bayesian and frequentist estimation and prediction for a normal population. Zbl 1192.62091
Ren, Cuirong; Sun, Dongchu; Dey, Dipak K.
2004
A new class of multivariate skew distributions with applications to Bayesian regression models. Zbl 1039.62047
Sahu, Sujit K.; Dey, Dipak K.; Branco, Márcia D.
2003
Prior and posterior predictive p-values in the one-sided location parameter testing problem. Zbl 1192.62088
Micheas, Athanasios C.; Dey, Dipak K.
2003
Variable selection for multivariate logistic regression models. Zbl 1027.62015
Chen, Ming-Hui; Dey, Dipak K.
2003
Modelling accelerated life test data by using a Bayesian approach. Zbl 1111.62327
Sinha, Debajyoti; Patra, Kauhsik; Dey, Dipak K.
2003
A first course in linear model theory. Zbl 1015.62067
Ravishanker, Nalini; Dey, Dipak K.
2002
Regression model under skew elliptical error distribution. Zbl 1076.62056
Branco, Márcia D.; Dey, Dipak K.
2002
Model determination for the variance component model using reference priors. Zbl 1023.62028
Chung, Younshik; Dey, Dipak K.
2002
A general class of change point and change curve models for life time data. Zbl 1015.62102
Patra, Kaushik; Dey, Dipak K.
2002
A general class of multivariate skew-elliptical distributions. Zbl 0992.62047
Branco, Márcia D.; Dey, Dipak K.
2001
Bayesian analysis of binary data using skewed logit models. Zbl 1020.62020
Chen, Ming-Hui; Dey, Dipak K.; Shao, Qi-Man
2001
Generalized linear models. A Bayesian perspective. Zbl 1006.00009
Dey, Dipak K.; Ghosh, Sujit K.; Mallick, Bani K.
2000
A comparison of frailty and other models for bivariate survival data. Zbl 0966.62086
Sahu, Sujit K.; Dey, Dipak K.
2000
Bayesian analysis for correlated ordinal data models. Zbl 1022.62030
Chen, Ming-Hui; Dey, Dipak K.
2000
Ranges of posterior expected losses and $$\epsilon$$-robust actions. Zbl 1281.62077
Dey, Dipak K.; Micheas, Athanasios C.
2000
A unified Bayesian approach for analyzing correlated ordinal response data. Zbl 0966.62045
Chen, Ming-Hui; Dey, Dipak K.
2000
Multivariate survival models with a mixture of positive stable frailties. Zbl 0971.62062
Ravishanker, Nalini; Dey, Dipak K.
2000
Multivariate process capability. A Bayesian perspective. Zbl 0968.62560
Niverthi, Murali; Dey, Dipak K.
2000
Bayesian approaches for overdispersion in generalized linear models. Zbl 1023.62070
Dey, Dipak K.; Ravishanker, Nalini
2000
Bayesian model diagnostics for correlated binary data. Zbl 1023.62030
Dey, Dipak K.; Chen, Ming-Hui
2000
Bayesian analysis of compositional data. Zbl 1023.62035
Iyengar, Malini; Dey, Dipak
2000
A new skewed link model for dichotomous quantal response data. Zbl 1072.62655
Chen, Ming-Hui; Dey, Dipak K.; Shao, Qi-Man
1999
On estimation with balanced loss functions. Zbl 0951.62019
Dey, Dipak K.; Ghosh, Malay; Strawderman, William E.
1999
Multivariate survival analysis with positive stable frailties. Zbl 1059.62688
Qiou, Zuqiang; Ravishanker, Nalini; Dey, Dipak K.
1999
A multivariate mixture of Weibull distributions in reliability modeling. Zbl 1055.62554
Patra, Kaushik; Dey, Dipak K.
1999
A new class of minimax estimators of multivariate normal mean vectors under balanced loss function. Zbl 1054.62508
Chung, Younshik; Kim, Chansoo; Dey, Dipak K.
1999
Practical nonparametric and semiparametric Bayesian statistics. Zbl 0893.00018
Dey, Dipak; Müller, Peter; Sinha, Debajyoti
1998
A simulation-intensive approach for checking hierarchical models. Zbl 0935.62082
Dey, Dipak K.; Gelfand, Alan E.; Swartz, Tim B.; Vlachos, Pantelis K.
1998
Bayesian modeling of correlated binary responses via scale mixture of multivariate normal link functions. Zbl 0976.62019
Chen, Ming-Hui; Dey, Dipak K.
1998
Bayesian analysis of multivariate survival data using Monte Carlo methods. Zbl 0910.62023
Aslanidou, Helen; Dey, Dipak K.; Sinha, Debajyoti
1998
Modeling publication bias using weighted distributions in a Bayesian framework. Zbl 1042.62525
Larose, Daniel T.; Dey, Dipak K.
1998
Bayesian approach to estimation of intraclass correlation using reference prior. Zbl 0917.62019
Chung, Younshik; Dey, Dipak K.
1998
A Bayesian approach using nonhomogeneous Poisson processes for software reliability models. Zbl 0936.62110
Achcar, J. A.; Dey, D. K.; Niverthi, M.
1998
A Bayesian approach to loss robustness. Zbl 0922.62014
Dey, Dipak K.; Lou, Kuo-ren; Bose, Sudip
1998
Survival analysis using semiparametric Bayesian methods. Zbl 0918.62087
Sinha, Debajyoti; Dey, Dipak K.
1998
Semiparametric Bayesian analysis of survival data. Zbl 1067.62520
Sinha, Debajyoti; Dey, Dipak K.
1997
Bayesian approach for nonlinear random effects models. Zbl 0911.62024
Dey, Dipak K.; Chen, Ming-Hui; Chang, Hong
1997
A Weibull regression model with gamma frailties for multivariate survival data. Zbl 0896.62125
Sahu, Sujit K.; Dey, Dipak K.; Aslanidou, Helen; Sinha, Debajyoti
1997
Overdispersed generalized linear models. Zbl 0890.62054
Dey, Dipak K.; Gelfand, Alan E.; Peng, Fengchun
1997
Bayesian approach to change point problems. Zbl 0954.62526
Dey, Dipak K.; Purkayastha, Sumitra
1997
A nonparametric approach to $$k$$-sample inference based on entropy. Zbl 0884.62042
Gangopadhyay, Ashis K.; Disario, Robert; Dey, Dipak K.
1997
Weighted distributions viewed in the context of model selection: A Bayesian perspective. Zbl 0852.62030
Larose, D. T.; Dey, D. K.
1996
Bayesian analysis of outlier problems using divergence measures. Zbl 0833.62028
Peng, Fengchun; Dey, Dipak K.
1995
Modeling expert opinion arising as a partial probabilistic specification. Zbl 0826.62007
Gelfand, Alan E.; Mallick, Bani K.; Dey, Dipak K.
1995
Bayesian model choice: Asymptotics and exact calculations. Zbl 0800.62170
Gelfand, A. E.; Dey, D. K.
1994
Robust Bayesian analysis using divergence measures. Zbl 0799.62003
Dey, Dipak K.; Birmiwal, Lea R.
1994
Bayesian robustness for multiparameter problems. Zbl 0798.62007
1994
Simultaneous estimation of Poisson means under weighted entropy loss. Zbl 0831.62022
Chung, Younshik; Kim, Chansoo; Dey, Dipak K.
1994
...and 34 more Documents
all top 5
all top 5
Cited in 147 Serials
101 Computational Statistics and Data Analysis 95 Journal of Multivariate Analysis 92 Journal of Statistical Planning and Inference 89 Communications in Statistics. Theory and Methods 54 Statistics & Probability Letters 52 Journal of Statistical Computation and Simulation 50 Biometrics 43 Journal of Applied Statistics 36 Statistical Papers 29 Statistics 26 Annals of the Institute of Statistical Mathematics 26 Test 24 Journal of Econometrics 24 Statistics and Computing 23 Lifetime Data Analysis 23 Brazilian Journal of Probability and Statistics 21 Communications in Statistics. Simulation and Computation 19 The Canadian Journal of Statistics 19 Computational Statistics 19 Journal of the Korean Statistical Society 17 Statistical Modelling 17 The Annals of Applied Statistics 16 The Annals of Statistics 16 Statistical Science 16 Statistical Methodology 14 Metrika 14 Scandinavian Journal of Statistics 11 Biometrical Journal 10 Metron 10 Statistical Methods and Applications 10 Bayesian Analysis 9 Psychometrika 8 Insurance Mathematics & Economics 8 European Journal of Operational Research 8 Chilean Journal of Statistics 7 Journal of the American Statistical Association 7 Journal of Mathematical Psychology 7 Economics Letters 7 Methodology and Computing in Applied Probability 7 Advances in Data Analysis and Classification. ADAC 6 Journal of Computational and Applied Mathematics 6 International Journal of Approximate Reasoning 5 Journal of the Royal Statistical Society. Series B. Statistical Methodology 5 Electronic Journal of Statistics 5 Journal of Agricultural, Biological, and Environmental Statistics 5 Sankhyā. Series A 4 Journal of Economic Dynamics & Control 4 Annals of Operations Research 4 Linear Algebra and its Applications 4 Journal of the Royal Statistical Society. Series C. Applied Statistics 4 Quantitative Finance 3 International Statistical Review 3 Bernoulli 3 Journal of Nonparametric Statistics 3 Journal of Systems Science and Complexity 3 Journal of Statistical Theory and Practice 3 AStA. Advances in Statistical Analysis 3 Sankhyā. Series B 3 Journal of Theoretical Biology 2 Journal of Computational Physics 2 Mathematical Biosciences 2 Journal of Classification 2 Acta Mathematicae Applicatae Sinica. English Series 2 Econometric Reviews 2 Random Operators and Stochastic Equations 2 Australian & New Zealand Journal of Statistics 2 Computational Geosciences 2 Probability in the Engineering and Informational Sciences 2 Journal of Applied Mathematics 2 Comptes Rendus. Mathématique. Académie des Sciences, Paris 2 Statistical Methods in Medical Research 2 Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A: Matemáticas. RACSAM 2 Journal of Probability and Statistics 2 Journal of Time Series Econometrics 2 Journal of Statistical Distributions and Applications 1 Computers & Mathematics with Applications 1 Computer Methods in Applied Mechanics and Engineering 1 Inverse Problems 1 Lithuanian Mathematical Journal 1 Mathematical Methods in the Applied Sciences 1 Physica A 1 Ukrainian Mathematical Journal 1 Automatica 1 British Journal of Mathematical & Statistical Psychology 1 Information Sciences 1 International Journal of Mathematics and Mathematical Sciences 1 Journal of Applied Probability 1 Kybernetika 1 Mathematics and Computers in Simulation 1 Opsearch 1 Proceedings of the American Mathematical Society 1 Journal of Information & Optimization Sciences 1 Acta Applicandae Mathematicae 1 American Journal of Mathematical and Management Sciences 1 Journal of the Japanese Society of Computational Statistics 1 Machine Learning 1 International Journal of Adaptive Control and Signal Processing 1 The Annals of Applied Probability 1 Applied Mathematical Modelling 1 Statistische Hefte ...and 47 more Serials
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Cited in 27 Fields
1,236 Statistics (62-XX) 221 Numerical analysis (65-XX) 121 Probability theory and stochastic processes (60-XX) 58 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 39 Biology and other natural sciences (92-XX) 17 Linear and multilinear algebra; matrix theory (15-XX) 14 Operations research, mathematical programming (90-XX) 10 Computer science (68-XX) 5 Geophysics (86-XX) 5 Information and communication theory, circuits (94-XX) 4 Combinatorics (05-XX) 4 Systems theory; control (93-XX) 2 History and biography (01-XX) 2 Nonassociative rings and algebras (17-XX) 2 Special functions (33-XX) 2 Dynamical systems and ergodic theory (37-XX) 2 Harmonic analysis on Euclidean spaces (42-XX) 2 Functional analysis (46-XX) 2 Calculus of variations and optimal control; optimization (49-XX) 1 General algebraic systems (08-XX) 1 Measure and integration (28-XX) 1 Ordinary differential equations (34-XX) 1 Integral transforms, operational calculus (44-XX) 1 Convex and discrete geometry (52-XX) 1 Differential geometry (53-XX) 1 Mechanics of deformable solids (74-XX) 1 Statistical mechanics, structure of matter (82-XX)
Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2021-10-22T03:38:54 |
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|
http://pdglive.lbl.gov/DataBlock.action?node=M081A02&home=sumtabM
|
# B( ${{\boldsymbol \chi}_{{b2}}{(2P)}}$ $\rightarrow$ ${{\boldsymbol \gamma}}{{\boldsymbol \Upsilon}{(2S)}}$ ) ${\times }$ B( ${{\boldsymbol \Upsilon}{(3S)}}$ $\rightarrow$ ${{\boldsymbol \gamma}}{{\boldsymbol \chi}_{{b2}}{(2P)}}$ ) ${\times }$ B( ${{\boldsymbol \Upsilon}{(2S)}}$ $\rightarrow$ ${{\boldsymbol \ell}^{+}}{{\boldsymbol \ell}^{-}}$ ) INSPIRE search
VALUE ($10^{-4}$) EVTS DOCUMENT ID TECN COMMENT
$\bf{ 2.74 \pm0.29}$ OUR AVERAGE
$3.22$ ${}^{+0.58}_{-0.53}$ ${}^{+0.16}_{-0.71}$ 1
2014 M
BABR ${{\mathit \Upsilon}{(3S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$
$2.49$ $\pm0.47$ $\pm0.31$ 53 2
1992 B
CLE2 ${{\mathit \Upsilon}{(3S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$
$2.74$ $\pm0.33$ $\pm0.18$ 3
1992
CSB2 ${{\mathit \Upsilon}{(3S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$
1 From a sample of ${{\mathit \Upsilon}{(3S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$ with converted photons.
2 CRAWFORD 1992B quotes 2${\times }$B( ${{\mathit \Upsilon}{(3S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \chi}_{{bJ}}{(2P)}}$ ) B( ${{\mathit \chi}_{{bJ}}{(2P)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \Upsilon}{(nS)}}$ ) B( ${{\mathit \Upsilon}{(nS)}}$ $\rightarrow$ ${{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ ).
3 Calculated by us. HEINTZ 1992 quotes B( ${{\mathit \Upsilon}{(3S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \chi}_{{b2}}{(2P)}}$ ) ${\times }$B( ${{\mathit \chi}_{{b2}}{(2P)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \Upsilon}{(2S)}}$ ) = ($1.90$ $\pm0.23$ $\pm0.18$) $\%$ using B( ${{\mathit \Upsilon}{(2S)}}$ $\rightarrow$ ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$ ) = ($1.44$ $\pm0.10)\%$.
References:
LEES 2014M
PR D90 112010 Bottomonium Spectroscopy and Radiative Transitions Involving the ${{\mathit \chi}_{{bJ}}{(1P,2P)}}$ States at BABAR
CRAWFORD 1992B
PL B294 139 Exclusive ${{\mathit \chi}{(2P)}}$ Production in ${{\mathit \Upsilon}{(3S)}}$ Decay
HEINTZ 1992
PR D46 1928 ${\mathit {\mathit b}}{\mathit {\overline{\mathit b}}}$ Spectroscopy from the ${{\mathit \Upsilon}{(3S)}}$ State
| 2020-02-27T05:36:03 |
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|
https://tjyj.stats.gov.cn/CN/10.19343/j.cnki.11-1302/c.2017.01.009
|
• 论文 •
### 我国高校扩招后办学效率和生产率的变化
• 出版日期:2017-01-15 发布日期:2017-02-09
### Efficiency and Productivity Change in the Chinese Higher Education Sector after University Enrollment Expansion
Zhong Wei & Jiang Wanjun
• Online:2017-01-15 Published:2017-02-09
Abstract: Does the high growth rate of the Chinese higher education sector during university enrollment expansion belong to an extensive mode? Does the Chinese higher education sector follow a new way of connotation-oriented development after reducing its scale of enrollment? Applying the method of DEA-Malmquist index, this study tries to response these two questions and analyzes the efficiency and productivity change in the MOE-administrated universities. The empirical results show that with the joint effect of technological progress and technical efficiency, although the former contributes more, the MOE-administrated universities achieve a high-quality development during university enrollment expansion. After 2006, the growth rate of productivity presents a downward trend for the decrease of technological progress and the natural aging of catch-up effect. However, when we use a quality index of output, the decreasing amount of technical efficiency is not obvious, which, to some extent, can prove the contribution of connotation-oriented development.
| 2022-10-07T06:28:38 |
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|
https://mechaelephant.com/dev/PCB-Notes/
|
# Dev Blog
./dev Original heme by orderedlist (CC-BY-SA) Where applicable, all content is licensed under a CC-BY-SA.
# PCB Notes
Copper thickness is commonly expressed in oz, for example 1 oz Cu. This is shorthand for the height of copper if spread over a square foot surface.
To calculate the height for 1 oz Cu, we need a few conversions:
• $1\ \mathrm{oz} = 0.0625\ \mathrm{lbs}$
• $\mathrm{Cu}\ \mathrm{density} = 8.96 \frac{\mathrm{g}}{\mathrm{cm}^3}$
• $1\ \mathrm{g} \approx 0.00220462\ \mathrm{lbs}$
• $1\ \mathrm{cm} \approx 0.393701\ \mathrm{in}$
This implies:
• $\mathrm{Cu}\ \mathrm{density} = \frac{8.96 \cdot 0.00220462\ \mathrm{lbs}}{(0.393701^3)\ \mathrm{in}^3} \approx 0.324 \frac{\mathrm{lbs}}{\mathrm{in}^3}$
• $h\ \mathrm{in} = \frac{1\ \mathrm{oz}}{ 1\ \mathrm{ft}^2 } = \frac{0.0625\ \mathrm{lbs}}{ 144\ \mathrm{in}^2 } \approx .00134$
Or, in general,
$$z\ \mathrm{oz}\ \mathrm{Cu} \rightarrow z \cdot 1.34\ \mathrm{mil}$$
Where $1\ \mathrm{mil} = \frac{1}{1000}\ \mathrm{in}$.
| 2019-02-20T13:02:41 |
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https://publications.industry.gov.au/publications/australianinnovationsystemmonitor/science-and-research/international-comparison/index.html
|
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# Science and Research3.5 International Comparison
## 3.5.1 Gross expenditure on R&D (GERD) as a share of GDP
Gross expenditure on R&D (GERD) is a key headline measure of a country's aggregate R&D activity. It is the sum of expenditures on R&D across all sectors of the economy, namely the business, government, higher education and private non-profit sectors. Australia's latest GERD estimate published by the ABS is $33.1 billion in 2017-18, which represents an increase of around 6.0 per cent from$31.2 billion in 2015-16.[86] However, Australia's national R&D intensity (GERD as a share of GDP) decreased from 1.88 per cent in 2015-16 to 1.79 per cent in 2017-18, remaining below the OECD average of 2.37 per cent in 2017. In the same period, Israel and South Korea had the highest national R&D intensities, 4.82 per cent and 4.29 per cent, respectively. National R&D intensity in Australia peaked at 2.25 per cent of GDP in 2008-09 and has been declining ever since.[87]
## 3.5.2 Gross expenditure on R&D (GERD) as a share of GDP by sector
GERD is the aggregate expenditure devoted to R&D by the business, government, higher education and private non-profit sectors. The largest component is business expenditure on R&D (BERD) and its stagnation in recent years has been a major factor driving the decline in Australia's GERD as a proportion of GDP (or national R&D intensity). The latest BERD to GDP estimate is 0.94 per cent in 2017-18, which represents a continuing decline from 1.18 per cent in 2013-14 and 1.00 per cent in 2015-16.[88] The intensity of government expenditure on R&D (GovERD to GDP) has also been declining but not nearly to the same extent, with latest estimate at 0.18 per cent in 2017-18. Meanwhile, the intensity of higher education expenditures on R&D (HERD to GDP) has remained relatively steady over the last five years or so, with the latest estimate at 0.60 per cent for 2017.[89] With BERD being a key driver of Australia's overall R&D intensity, the GERD to GDP estimate should be interpreted in the context of other information, particularly the cyclical and structural changes affecting the Mining and Manufacturing industries.[90]
## 3.5.3 Business expenditure on R&D (BERD) performed in service industries
Across OECD countries, a sizeable and growing share of BERD is performed in service industries. Service industries produce services, as opposed to physical goods. For example, services include accommodation, recreation, health, education, retail, as well as information and communication technologies (ICTs). In Australia, the share of BERD performed by service industries in 2017-18 was around 61.5 per cent — well above the OECD average of 45.5 per cent. Australia ranks 6th of 32 OECD economies on this metric.[91] Only five years earlier, Australian service industries accounted for less than half of total BERD, and a decade ago it was barely above 40 per cent. This broad economic shift towards service industries is occurring across nearly all OECD economies, in part due to the rapid growth in the uptake of new digital technologies. Across OECD economies, ICTs account for a substantial and growing part of BERD, and are disproportionately represented by innovative businesses.[92]
| 2020-07-05T23:34:45 |
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|
https://www.aimsciences.org/article/doi/10.3934/dcdss.2014.7.631
|
Article Contents
Article Contents
# An excess-decay result for a class of degenerate elliptic equations
• We consider a family of degenerate elliptic equations of the form div $(\nabla F(\nabla u)) = f$, where $F\in C^{1,1}$ is a convex function which is elliptic outside a ball.We prove an excess-decay estimate at points where $\nabla u$ is close to a nondegenerate value for $F$. This result applies to degenerate equations arising in traffic congestion, where we obtain continuity of $\nabla u$ outside the degeneracy, and to anisotropic versions of the $p$-laplacian, where we get Hölder regularity of $\nabla u$.
Mathematics Subject Classification: Primary: 35J70; Secondary: 35B65, 49K20.
Citation:
• [1] E. Acerbi and N. Fusco, A regularity theorem for minimizers of quasiconvex integrals, Arch. Rational Mech. Anal., 99 (1987), 261-281.doi: 10.1007/BF00284509. [2] E. Acerbi and N. Fusco, Local regularity for minimizers of nonconvex integrals, Ann. Scuola Norm. Sup. Pisa Cl. Sci., 16 (1989), 603-636. [3] G. Anzellotti and M. Giaquinta, Convex functionals and partial regularity, Arch. Rational Mech. Anal., 102 (1988), 243-272.doi: 10.1007/BF00281349. [4] L. Brasco, Global $L^\infty$ gradient estimates for solutions to a certain degenerate elliptic equation, Nonlinear Anal., 74 (2011), 516-531.doi: 10.1016/j.na.2010.09.006. [5] L. Brasco, G. Carlier and F. Santambrogio, Congested traffic dynamics, weak flows and very degenerate elliptic equations, J. Math. Pures Appl., 93 (2010), 652-671.doi: 10.1016/j.matpur.2010.03.010. [6] M. Colombo and A. Figalli, Regularity results for very degenerate elliptic equations, J. Math. Pures Appl., 101 (2014), 94-117.doi: 10.1016/j.matpur.2013.05.005. [7] D. De Silva and O. Savin, Minimizers of convex functionals arising in random surfaces, Duke Math. J., 151 (2010), 487-532.doi: 10.1215/00127094-2010-004. [8] E. DiBenedetto, $C^{1+\alpha }$ local regularity of weak solutions of degenerate elliptic equations, Nonlinear Anal., 7 (1983), 827-850.doi: 10.1016/0362-546X(83)90061-5. [9] L. Esposito, G. Mingione and C. Trombetti, On the Lipschitz regularity for certain elliptic problems, Forum Math., 18 (2006), 263-292.doi: 10.1515/FORUM.2006.016. [10] L. C. Evans, A new proof of local $C^{1,\alpha }$ regularity for solutions of certain degenerate elliptic p.d.e., J. Differential Equations, 45 (1982), 356-373.doi: 10.1016/0022-0396(82)90033-X. [11] I. Fonseca, N. Fusco and P. Marcellini, An existence result for a nonconvex variational problem via regularity, ESAIM Control Optim. Calc. Var., 7 (2002), 69-95.doi: 10.1051/cocv:2002004. [12] M. Giaquinta, Multiple Integrals in the Calculus of Variations and Nonlinear Elliptic Systems, Princeton Univ. Press, Princeton, 1983. [13] M. Giaquinta and G. Modica, Partial regularity of minimizers of quasiconvex integrals, Ann. Inst. H. Poincaré, Analyse non linéaire, 3 (1986), 185-208. [14] D. Gilbarg and N. S. Trudinger, Elliptic Partial Differential Equations of Second Order, reprint of the 1998 edition, Classics in Mathematics, Springer-Verlag, Berlin, 2001. [15] C. Imbert and L. Silvestre, Estimates on elliptic equations that hold only where the gradient is large, preprint, (2013). [16] J. L. Lewis, Regularity of the derivatives of solutions to certain degenerate elliptic equations, Indiana Univ. Math. J., 32 (1983), 849-858.doi: 10.1512/iumj.1983.32.32058. [17] F. Santambrogio and V. Vespri, Continuity in two dimensions for a very degenerate elliptic equation, Nonlinear Anal., 73 (2010), 3832-3841.doi: 10.1016/j.na.2010.08.008. [18] O. Savin, Small perturbation solutions for elliptic equations, Comm. Partial Differential Equations, 32 (2007), 557-578.doi: 10.1080/03605300500394405. [19] P. Tolksdorff, Regularity for a more general class of quasi-linear elliptic equations, J. Differential Equations, 51 (1984), 126-150.doi: 10.1016/0022-0396(84)90105-0. [20] K. Uhlenbeck, Regularity for a class of non-linear elliptic systems, Acta Math., 138 (1977), 219-240.doi: 10.1007/BF02392316. [21] N. N. Uraltseva, Degenerate quasilinear elliptic systems, Zap. Naučn. Sem. Leningrad. Otdel. Mat. Inst. Steklov. (LOMI), 7 (1968), 184-222. [22] L. Wang, Compactness methods for certain degenerate elliptic equations, J. Differential Equations, 107 (1994), 341-350.doi: 10.1006/jdeq.1994.1016.
Open Access Under a Creative Commons license
| 2023-03-27T14:03:20 |
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https://par.nsf.gov/biblio/10249682-mosdef-lris-survey-interplay-between-massive-stars-ionized-gas-high-redshift-star-forming-galaxies1
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The MOSDEF-LRIS Survey: The Interplay Between Massive Stars and Ionized Gas in High-Redshift Star-Forming Galaxies1
Abstract We present a joint analysis of rest-UV and rest-optical spectra obtained using Keck/LRIS and Keck/MOSFIRE for a sample of 62 star-forming galaxies at z ∼ 2.3. We divide our sample into two bins based on their location in the [OIII]5007/Hβ vs. [NII]6584/Hα BPT diagram, and perform the first differential study of the rest-UV properties of massive ionizing stars as a function of rest-optical emission-line ratios. Fitting BPASS stellar population synthesis models, including nebular continuum emission, to our rest-UV composite spectra, we find that high-redshift galaxies offset towards higher [OIII]λ5007/Hβ and [NII]λ6584/Hα have younger ages ($\log (\textrm {~Age/yr})=7.20^{+0.57}_{-0.20}$) and lower stellar metallicities ($Z_*=0.0010^{+0.0011}_{-0.0003}$) resulting in a harder ionizing spectrum, compared to the galaxies in our sample that lie on the local BPT star-forming sequence ($\log (\textrm {Age/yr})=8.57^{+0.88}_{-0.84}$, $Z_*=0.0019^{+0.0006}_{-0.0006}$). Additionally, we find that the offset galaxies have an ionization parameter of $\log (U)=-3.04^{+0.06}_{-0.11}$ and nebular metallicity of ($12+\log (\textrm {~O/H})=8.40^{+0.06}_{-0.07}$), and the non-offset galaxies have an ionization parameter of $\log (U)=-3.11^{+0.08}_{-0.08}$ and nebular metallicity of $12+\log (\textrm {~O/H})=8.30^{+0.05}_{-0.06}$. The stellar and nebular metallicities derived for our sample imply that the galaxies offset from the local BPT relation are more α-enhanced ($7.28^{+2.52}_{-2.82}\textrm {~O/Fe}_{\odot }$) compared to those consistent with the local sequence more »
Authors:
; ; ; ; ; ; ;
Award ID(s):
Publication Date:
NSF-PAR ID:
10249682
Journal Name:
Monthly Notices of the Royal Astronomical Society
Volume:
495
Issue:
4
Page Range or eLocation-ID:
4430-4444
ISSN:
0035-8711
National Science Foundation
##### More Like this
1. ABSTRACT We analyse the rest-optical emission-line spectra of z ∼ 2.3 star-forming galaxies in the complete MOSFIRE Deep Evolution Field (MOSDEF) survey. In investigating the origin of the well-known offset between the sequences of high-redshift and local galaxies in the [O iii]λ5008/Hβ versus [N ii]λ6585/Hα (‘[N ii] BPT’) diagram, we define two populations of z ∼ 2.3 MOSDEF galaxies. These include the high population that is offset towards higher [O iii]λ5008/Hβ and/or [N ii]λ6585/Hα with respect to the local SDSS sequence and the low population that overlaps the SDSS sequence. These two groups are also segregated within the [O iii]λ5008/Hβ versus [S ii]λλ6718,6733/Hα and the [O iii]λλ4960,5008/[O ii ]λλ3727,3730 (O32) versus ([O iii]λλ4960,5008+[O ii]λλ3727,3730)/Hβ (R23) diagrams, which suggests qualitatively that star-forming regions in the more offset galaxies are characterized by harder ionizing spectra at fixed nebular oxygen abundance. We also investigate many galaxy properties of the split sample and find that the high sample is on average smaller in size and less massive, but has higher specific star formation rate (SFR) and SFR surface density values and is slightly younger compared to the low population. From Cloudy+BPASS photoionization models, we estimate that the high population has a lower stellar metallicity (i.e. harder ionizing spectrum) but slightly higher nebular metallicity and higher ionizationmore »
2. ABSTRACT We present constraints on the massive star and ionized gas properties for a sample of 62 star-forming galaxies at z ∼ 2.3. Using BPASS stellar population models, we fit the rest-UV spectra of galaxies in our sample to estimate age and stellar metallicity which, in turn, determine the ionizing spectrum. In addition to the median properties of well-defined subsets of our sample, we derive the ages and stellar metallicities for 30 high-SNR individual galaxies – the largest sample of individual galaxies at high redshift with such measurements. Most galaxies in this high-SNR subsample have stellar metallicities of 0.001 < Z* < 0.004. We then use Cloudy + BPASS photoionization models to match observed rest-optical line ratios and infer nebular properties. Our high-SNR subsample is characterized by a median ionization parameter and oxygen abundance, respectively, of log (U)med = −2.98 ± 0.25 and 12 + log (O/H)med = 8.48 ± 0.11. Accordingly, we find that all galaxies in our sample show evidence for α-enhancement. In addition, based on inferred log (U) and 12 + log (O/H) values, we find that the local relationship between ionization parameter and metallicity applies at z ∼ 2. Finally, we find that the high-redshift galaxies most offset from the local excitation sequence in the BPT diagram aremore »
3. ABSTRACT
The ionizing photon escape fraction [Lyman continuum (LyC) fesc] of star-forming galaxies is the single greatest unknown in the reionization budget. Stochastic sightline effects prohibit the direct separation of LyC leakers from non-leakers at significant redshifts. Here we circumvent this uncertainty by inferring fesc using resolved (R > 4000) Lyman α (Lyα) profiles from the X-SHOOTER Lyα survey at z = 2 (XLS-z2). With empirically motivated criteria, we use Lyα profiles to select leakers ($f_{\mathrm{ esc}} > 20{{\ \rm per\ cent}}$) and non-leakers ($f_{\mathrm{ esc}} < 5{{\ \rm per\ cent}}$) from a representative sample of >0.2L* Lyman α emitters (LAEs). We use median stacked spectra of these subsets over λrest ≈ 1000–8000 Å to investigate the conditions for LyC fesc. Our stacks show similar mass, metallicity, MUV, and βUV. We find the following differences between leakers versus non-leakers: (i) strong nebular C iv and He ii emission versus non-detections; (ii) [O iii]/[O ii] ≈ 8.5 versus ≈3; (iii) Hα/Hβ indicating no dust versus E(B − V) ≈ 0.3; (iv) Mg ii emission close to the systemic velocity versus redshifted, optically thick Mg ii; and (v) Lyα fesc of ${\approx} 50{{\ \rm per\ cent}}$ versus ${\approx} 10{{\ \rm per\ cent}}$. The extreme equivalent widths (EWs) in leakers ([O iii]+$\mathrm{ H}\beta \approx 1100$ Å rest frame)more »
4. ABSTRACT
We present detections of [O iii] λ4363 and direct-method metallicities for star-forming galaxies at z = 1.7–3.6. We combine new measurements from the MOSFIRE Deep Evolution Field (MOSDEF) survey with literature sources to construct a sample of 18 galaxies with direct-method metallicities at z > 1, spanning 7.5 < 12+log(O/H) < 8.2 and log(M*/M⊙) = 7–10. We find that strong-line calibrations based on local analogues of high-redshift galaxies reliably reproduce the metallicity of the z > 1 sample on average. We construct the first mass–metallicity relation at z > 1 based purely on direct-method O/H, finding a slope that is consistent with strong-line results. Direct-method O/H evolves by ≲0.1 dex at fixed M* and star formation rate from z ∼ 0 to 2.2. We employ photoionization models to constrain the ionization parameter and ionizing spectrum in the high-redshift sample. Stellar models with supersolar O/Fe and binary evolution of massive stars are required to reproduce the observed strong-line ratios. We find that the z > 1 sample falls on the z ∼ 0 relation between ionization parameter and O/H, suggesting no evolution of this relation from z ∼ 0 to z ∼ 2. These results suggest that the offset of the strong-line ratios of this sample from local excitation sequences is driven primarilymore »
5. Abstract
The Baldwin, Philips, & Terlevich diagram of [Oiii]/Hβversus [Nii]/Hα(hereafter N2-BPT) has long been used as a tool for classifying galaxies based on the dominant source of ionizing radiation. Recent observations have demonstrated that galaxies atz∼ 2 reside offset from local galaxies in the N2-BPT space. In this paper, we conduct a series of controlled numerical experiments to understand the potential physical processes driving this offset. We model nebular line emission in a large sample of galaxies, taken from thesimbacosmological hydrodynamic galaxy formation simulation, using thecloudyphotoionization code to compute the nebular line luminosities from Hiiregions. We find that the observed shift toward higher [Oiii]/Hβand [Nii]/Hαvalues at high redshift arises from sample selection: when we consider only the most massive galaxiesM*∼ 1010–11M, the offset naturally appears, due to their high metallicities. We predict that deeper observations that probe lower-mass galaxies will reveal galaxies that lie on a locus comparable toz∼ 0 observations. Even when accounting for samples-selection effects, we find that there is a subtle mismatch between simulations and observations. To resolve this discrepancy, we investigate the impact of varying ionization parameters, Hiiregion densities, gas-phase abundance patterns, and increasing radiation field hardness on N2-BPT diagrams. We find that either decreasing themore »
| 2023-01-31T13:43:42 |
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http://www.legisquebec.gouv.qc.ca/en/showversion/cr/H-4.2,%20r.%203?code=se:33&pointInTime=20210106
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### H-4.2, r. 3 - Regulation respecting petroleum exploration, production and storage licences, and the pipeline construction or use authorization
33. Not later than 45 days after having been informed of the selection, the successful bidder must provide to the Minister
(1) the amount tendered for the licence;
(2) the proof of solvency provided for in section 165;
(3) the process for appointing members of the monitoring committee or, if the bidder is not required to establish a new committee under the first paragraph of section 16, identify the monitoring committee that will be consulted for that licence;
(4) a summary of the anticipated exploration work for the term of the licence specifying the objectives, nature and scope; and
(5) the payment of the annual fee payable under section 42 for the first year of the licence.
O.C. 1253-2018, s. 33.
In force: 2018-09-20
33. Not later than 45 days after having been informed of the selection, the successful bidder must provide to the Minister
(1) the amount tendered for the licence;
(2) the proof of solvency provided for in section 165;
(3) the process for appointing members of the monitoring committee or, if the bidder is not required to establish a new committee under the first paragraph of section 16, identify the monitoring committee that will be consulted for that licence;
(4) a summary of the anticipated exploration work for the term of the licence specifying the objectives, nature and scope; and
(5) the payment of the annual fee payable under section 42 for the first year of the licence.
O.C. 1253-2018, s. 33.
| 2021-02-24T21:27:12 |
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https://read.dukeupress.edu/demography/article/58/4/1499/173902/Family-Income-Level-Variability-and-Trend-as
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## Abstract
Recent decades have seen increases in the variability of family income, tepid income growth rates for all but the richest families, and widening income inequality. These trends are concerning for child well-being, given the importance of income to parental investments and parenting practices. Growing evidence suggests that a high level of change is disruptive to family processes and that chronic stress affects physiology as well as psychology. This study used the Panel Study of Income Dynamics Child Development Supplement to estimate associations between three dimensions of childhood income dynamics—level, variability, and trend—and child achievement and behavior. After income level was controlled for, income variability during childhood was not associated with child achievement or behavior, but an increasing five-year trend in income-to-needs was modestly beneficial to behavior measures. Subgroup analysis suggests some adverse effects of income variability and trend on reading and behavior for non-White children but no clear patterns by child's age or family income or wealth levels.
## Introduction
The dynamic nature of family economic circumstances is a growing focus in multiple social science fields. In particular, recent studies documented high levels of variability in family income both between and within years, particularly for lower socioeconomic status (SES) and non-White families (Dynan et al. 2012; Hardy and Ziliak 2014; Western et al. 2016). This trend is consistent with—and likely driven by—growing instability in employment, family structure, and public assistance (Cavanagh and Fomby 2019; Ha et al. 2020; Hardy 2017; Kalleberg 2010). The disruptions to family life and the economy associated with the COVID-19 pandemic are poised to exacerbate these trends.
Although hundreds of studies across disciplines considered the influence of family income level on child well-being (for a review, see Gennetian et al. 2010), we know less about the effects of income dynamics on child development because so few data sources offer longitudinal measures at regular intervals of both family income and developmental outcomes. A handful of studies suggested that greater income variability has small negative effects on school outcomes, both in adolescence and in adulthood (Gennetian et al. 2018b; Gennetian et al. 2015; Hardy 2014). Important, unanswered questions include whether income variability and trend have effects on the development of younger children or in other domains, and whether those effects are moderated by race or SES.
Using the Panel Study of Income Dynamics (PSID) core and Child Development Supplement I (CDS) data, I estimated relations between income dynamics and child achievement and behavior. The PSID offers high-quality income and child outcome data, a rich set of covariates, and important potential moderators, including race and family wealth. Based on prior studies and insights from developmental psychology and neuroscience about the consequences of repeated change, I ask the following questions about income dynamics and child development:
1. Are income variability and trend associated with child achievement and behavior after income level is controlled for?
2. Are there threshold effects of high income variability, or negative or no income trend, on child achievement and behavior after income level is controlled for?
3. Do the associations between income variability or trend and child achievement and behavior vary by child's age or race?
4. Do the associations between income variability or trend and child achievement and behavior vary by family SES, as measured by income level or wealth?
This study contributes to an understanding of the dynamic nature of family life and particularly whether economic instability is a unique form of disadvantage. It distinguishes the salience of income level, variability, and trend for child development both conceptually and empirically. The analysis provides estimates of the effects of income variability and the trend in income-to-needs on developmental domains and age groups not previously studied. The results are essential for population science because income variability and other forms of instability have potential implications for processes of social stratification and mobility (Hacker 2008; Western et al. 2012) and for child well-being (Sandstrom and Huerta 2013). Importantly, U.S. income support programs focus largely on raising income level or subsidizing basic needs and may not be well designed to promote stability of economic circumstances during childhood.
## Background
Income dynamics during the life course is a function of three dimensions: level, variability, and trend (Duncan 1988). In any period, income level is what economists refer to as permanent income, which captures the average resources available to the family across the entire period (Friedman 1957). Income variability or volatility (used synonymously here) is the change in income around the average (Dynan et al. 2012; Gottschalk and Moffitt 2009; Hardy 2017). Income trend is the direction and slope of income change from the beginning to the end of the period. Distinguishing income trend from income variability during childhood is critical because mobility itself is a form of variability, albeit one that may be beneficial to children.
### Trends in Childhood Income Dynamics
Recent trends in childhood income dynamics reflect the population-level increases in income inequality. Childhood income levels have diverged over time by parents' education, with nearly all the growth since the 1970s among highly educated, high-income parents (Hill 2018; Lichter and Eggebeen 1993; Western et al. 2016). Earnings and income variability increased in that same period, particularly for lower-SES and non-White families (Dahl et al. 2011; Gottschalk and Moffitt 2009; Hardy 2012; Hardy and Ziliak 2014). These trends were driven by increasing divergence in employment and family structure stability by SES (Kalleberg 2010; McLanahan 2004; Western et al. 2016). Independent of economic cycles, both between- and within-job instability have increased for workers in low-paying jobs as employers shifted away from standard long-term employment arrangements toward a variety of contingent arrangements (Kalleberg 2010). Simultaneously, family structure changes during childhood—including divorce, repartnering, relationship churning, and coresidence with other family members—became normative, particularly for children with less-educated parents (Perkins 2017; Turney and Halpern-Meekin 2017). As employment and family instability increased, income support programs became less able to smooth family income (Ben-Ishai 2015; Hardy 2017).
Less is known about how income trends during childhood have changed over time. Hill (2008) found that the positive growth rate of family income during childhood declined from 3% or 4% in the 1970s and 1980s to 1% in the double-recession 2000s. On average, family and household incomes increase with child's age, primarily because parental earnings increase with age and work experience but also because adolescents can contribute work earnings to households (Duncan 1988). This age-normed expectation is supported by evidence that the risk of being poor declines for adults as they move from their 20s into middle age (and then increases again in later life; Sandoval 2009). In addition, life events such as parental death, divorce, incarceration, or a health crisis can drastically alter income trends during childhood.
### Income Dynamics and Child Development
Higher income during childhood is beneficial to children in every domain of health and development (for reviews, see Bradley and Corwyn 2002; Case et al. 2002; Gennetian et al. 2010). Family income affects child development indirectly through parental investments and parenting practices. Parents can use higher income to purchase more and better food, housing, childcare, and schooling, all of which create the contexts for positive child health and development in multiple domains (Becker 1981; Bradley and Corwyn 2002). Also, more income leads to less stress, which is associated with warmer and more responsive parenting (the Family Economic Stress Model; e.g., Conger et al. 1992; McLoyd 1990; Mistry et al. 2009), a particularly salient pathway for effects on child social and emotional development (Guo and Harris 2000; Yeung et al. 2002). There is evidence of both linear and nonlinear effects of income on child achievement: an additional dollar is associated with improved outcomes, although so too is living above the poverty line, and an additional dollar has stronger effects if income level is low (Dearing et al. 2001; Duncan et al. 2012; Gennetian et al. 2010). Finally, income is also a mechanism by which other aspects of family life, such as family structure and parental employment, can affect children. In this study, however, I focus on income as a developmental context rather than as the mechanism for other contexts.
Conventionally, studies on income and child development “average out” variability in multiple income measures to better capture the resources available to families across time. Average income has been shown to relate more strongly than does any year's income level to family and child outcomes (e.g., Blau 1999; Dahl and Lochner 2012). Also, the permanent income hypothesis from economics posits that families can smooth income and consumption with savings when income varies (Friedman 1957). Importantly, this hypothesis is unlikely to hold for many low- and moderate-income families, or for African American and Hispanic families, who have less access to credit and far lower levels of wealth than White families (Dynarski and Gruber 1997; Hamilton and Darity 2017; McKernan et al. 2013).
#### Income Variability
Income variability was measured as the standard deviation of yearly arc percentage change (APC), a measure that has the advantages of being calculable with a zero value in one period and of producing symmetric values for positive and negative changes of the same size. APC was calculated in each year of the survey using the following equation:
$APC =100 . (Yt−Yt − 1)/(Yt+Yt − 12),$
(2)
where Y is family income; and t indexes years of data. APC is bounded by −200 and 200, and changes to and from 0 are measured as −200 or 200 APC. I also tested the sensitivity of the results to an alternative measure of income variability—the transitory variance of income—measured as the standard deviation of yearly income across five years. The economics literature on income has used this measure extensively, often after adjusting for life-course effects by controlling for age (Dynan et al. 2012; Hardy 2014).
To examine potentially nonlinear effects of variability, I also used a “high variability” measure, defined as greater than the median standard deviation APC. There is also reason to expect that the magnitude of a given change in income would relate to its effects on children. In keeping with prior studies, I created count variables of the number of year-to-year income changes of 25% or more (Hardy 2014) and tested the results using an alternative threshold of 50% (Dahl et al. 2011). I included separate counts of large gains and large losses to examine the effects of income insecurity (Western et al. 2016).
#### Income Trend
The direction and size of income growth over time were measured as the annual growth rate in the yearly family income-to-needs ratio. Income-to-needs ratios—that is, family income relative to the poverty line for family size and structure—help to account for the fact that families grow over time and require more income. The growth rate was calculated as the exponentiated coefficient minus 1 on a continuous variable capturing year in an OLS regression predicting the natural logarithm of family income-to-needs. I also used a dichotomous measure of negative or zero growth.
It is important for the conceptualization and measurement of income dynamics to note that these measures of level, variability, and growth are not highly correlated. As shown in Table 3, the correlation between level and variability is −0.22 (p < .001); the correlation between level and growth is −0.05 (p < .01); and that between variability and growth is 0.13 (p < .001). That the three dimensions are empirically distinguishable lends support to this study's attempt to distinguish them conceptually and to understand their unique influences on child development.
#### Child Achievement and Behavior
The dependent variables include two measures of child cognition and two measures of child behavior. The achievement measures were taken from the Woodcock-Johnson Psycho-Educational Battery-Revised (WJ-R), normed tests for measuring academic achievement. In the CDS, reading and math subtests of the WJ-R were administered to children ages 6 years or older in each wave. Children 3 to 5 years old were administered only one of four reading subtests: the letter-word identification (relevant only in Wave 1, when some sample children were under 6 years old; Duffy and Sastry 2014). The Spanish version of the WJ-R (Batería-R, Form A) was used for children whose primary language was Spanish. The normed scores were constructed based on the child's raw score on the test and the child's age to the nearest month. In this sample, the range for math (applied problems and calculation subtests in the WJ-R) was 19 to 184 points, and the mean score was 105.99 points (SD = 17.32). The range for the broad reading scores (letter-word and passage comprehension subtests) was 9 to 194 points, and the mean was 105.18 (SD = 17.29).
The behavior measures were obtained from the Behavior Problem Index (BPI) and the Positive Behavior Scale (PBS), commonly used and well-validated measures of child behavior. The BPI, which is based on Achenbach's behavior problem checklist, measures the incidence and severity of child behavior problems, such as acting out, being anxious or withdrawn, and acting hyperactive (Achenbach 1994). The BPI scale was based on responses by the primary caregiver as to whether 32 problem behaviors are often, sometimes, or never true of the targeted child. The BPI scores ranged from 0 to 30 points, with a mean of 8.28 (SD = 6.23). I also examined the results for two important subscales of the BPI: externalizing and internalizing problem behavior. The former captures disruptive behaviors, and the latter captures anxious or depressed behaviors.
The PBS measures childhood emotional and social competence (Quint et al. 1997). The original scale consisted of 25 items for children 3 years or older evaluated on a 10-point scale, ranging from “not at all like my child” to “very much like my child.” Questions ask the parent about the child being “cheerful,” “getting along with others,” and getting “over being upset quickly.” The CDS used 10 of these items, each scored from 1 to 5. In this sample, the PBS ranged from 0 to 5, with a mean of 4.17 (SD = 0.58).
#### Covariates and Moderators
The following time-invariant child characteristics were used from the first wave of the CDS: whether the child had low birth weight, whether the child was breastfed, the child's gender, and the child's race. I also controlled for two time-variant child characteristics, measured at each CDS wave: the child's living circumstances and the child's age in years. The child's living circumstances were measured in three mutually exclusive dichotomous variables: living with both parents, living with the mother only, and other (includes living with father only). In addition, in supplementary analyses, I controlled explicitly for family (in)stability using a binary indicator for whether the child's living circumstances were stable from one wave to the next (starting with Wave 2). More than 80% of the sample had no change in living circumstances across waves.
The direction of associations between the control variables and child development was generally expected and consistent with prior research. Average achievement is lower for non-White children, those not breastfed, and children with lower-educated parents. Some of the same characteristics are associated with adverse behavior but much less consistently. Notably, the statistically significant associations between five-year income dynamics and child achievement and behavior are much smaller in size than the associations between other child and family characteristics and those outcomes. For example, a $1,000 increase in income is associated with a 0.05 point increase on a standardized math test, but the child living in a household with a less-educated head is associated with a 7.8 point decrease in reading scores relative to higher-educated parents. The results in Table 4 were robust to a variety of alternative specifications (results not shown), including using the standard deviation of income (transitory variance) to measure income variability, using Poisson regression for the highly skewed outcome of positive social behavior, and using total wealth as a control variable instead of homeownership. Also, in the structure of the data, there was temporal overlap between the Wave 2 income measures (1998, 2000, and 2002) and the child outcome measures (2002), raising concern about bias from simultaneity. For example, a child's behavior problems might lead to parental job loss and greater income variability. In models dropping Wave 2, the direction and statistical significance of the effects of income level remain the same, but higher standard deviation APC is related to a small marginally significant increase in problem behavior scores (0.005 points; p < .10). I also estimated the main models predicting the problem behavior externalizing and internalizing subscales separately and found that income level and trend are associated with a reduction in both types of behavior problems but that income variability does not have statistically significant associations with either. Finally, a likely cause of income instability is a change in family composition or structure. Although this study was not focused on examining the causes of income variability, I did examine whether the relationships between income dynamics and child achievement and behavior might vary for children in (un)stable families (results not shown). I first controlled for a binary indicator of whether the child's living arrangements (i.e., which biological parents they were living with) changed from the prior wave, which dropped the first wave of data. With the inclusion of this control, the size of the coefficients on income level, variability, and trend all decreased slightly but with few differences in the statistical significance of those coefficients. The one exception was that the associations between income trend and behavior were no longer statistically significant. Limiting the sample to only children with unstable family structures also did not alter the pattern of mostly null effects. ### Threshold Effects of High Variability or Low Trend Table 5 shows the results of models using three types of categorical indicators for high thresholds of variability that would arguably be most disruptive. All these models controlled for continuous measures of income level and the standard set of control variables shown in Table 4. The results in panel A used high variability (above-median standard deviation of APC) and stagnant or downward trend (a growth rate less than or equal to 0). Panels B and C show results from models testing the hypothesis that large income gains or losses between years might be particularly disruptive to families. The results show minimal evidence that high variability or stagnant/negative growth is associated with child development (Table 5, panel A). High income variability has a negative association with math and reading scores, but the point estimates are not statistically significant. In Panel B, the coefficients become larger (more adverse) with an increasing number of large income changes that a household experienced, but none of the coefficients are statistically different from 0, and few are statistically different from each other. The evidence on the direction of large changes is comparable (panel C), with no statistically significant associations with any outcomes. When I changed the definition of “large” income change to 50% rather than 25% (results not shown), the adverse associations between large changes and both achievement scores grew in magnitude, and two or more large income changes were negatively and significantly (p < .05) associated with reading scores. In addition, negative associations between gains only and losses and gains with reading scores were both negative and statistically significant (p < .10 and p < .05, respectively). Compared with the linear results in Table 4, these results provide little evidence that income changes might be most detrimental when larger and more frequent. ### Moderating Effects of Child's Age and Race Table 6 displays the results of the main models using continuous income dynamic measures and the full set of controls to predict child achievement and behavior by subgroups based on child's race (White versus non-White) and age (adolescents vs. nonadolescents). As noted in the Methods section, these crude groupings are necessitated by the relatively small sample of children in the PSID-CDS. In general, the effect of income dynamics is more pronounced for non-White than White children. The associations between income level and achievement test scores are statistically significant in both groups but were larger for non-White children (p < .10). Also, the following associations are significant only for the non-White subgroup: between income level and problem behavior (−0.02; p < .001); between income variability and reading (−0.02; p < .10), problem behavior scores (0.01; p < .10), and positive social behavior (−0.00; p < .10); and between yearly income growth rate and positive social behavior (0.002; p < .01). For problem behavior and positive social behavior, the differences in the magnitudes of the coefficients on variability for Whites and non-Whites are statistically significant (shown with an “a” superscript; p < .10). Many of the associations between income dynamics and achievement are larger for younger children than for adolescents, but the coefficients are not statistically different from 0 or one another (except the association between income level and math scores). For behavior, the magnitude of the associations with income variability and trends appear identical between adolescents and nonadolescents. ### Moderating Effects of Income and Wealth Levels To test the moderating role of income and wealth levels, I predicted the child outcomes with the measures for variability and trend interacted with an indicator equal to 1 if the family's income was below the median ($54,580) or if the family's wealth (assets-debt) was below the median (\$22,270). The predicted margins from these partially interacted models are shown graphically in panels a–h of both Figure 2 (income) and Figure 3 (wealth). The coefficients are shown in Table A1 of the online appendix.
The associations between income variability or trend and child achievement and behavior do not vary by median income. Notably, the association between income variability and achievement scores is negative but not statistically significant for the lower-income families. Even in cases in which the relationship looks different in Figure 2 for those with income below the median and at or above the median (e.g., the association between growth rate and reading scores), the coefficient on the interaction term is not statistically significant. The story is similar for wealth, with one exception: income growth is promotive of higher test scores only for families at or above median wealth. The relationship between income growth rate and test scores is negative when families have below-median wealth. The interaction between below-median wealth and growth rate is statistically significant for math but not for reading (Table A1).
## Discussion
This study examined three dimensions of childhood income dynamics—level, trend, and variability—as predictors of child achievement and behavior. After income level was controlled for, income variability had null associations with child achievement and behavior. In contrast, income trend had modest beneficial associations with both measures of behavior but neither measure of achievement. I found modest and suggestive evidence of threshold effects, such that multiple large changes and having both gains and losses were predictive of lower test scores, on average; again, though, the point estimates were not statistically significant. The subgroup analyses found larger adverse effects of income variability for non-White than White children. The results did not differ statistically for adolescents and nonadolescents in the sample, but the coefficients were larger for the children under 13 years. Finally, contrary to expectations, there was no clear pattern of differences in the associations between income variability and trend by a family's income or wealth level.
The results of this study have three key implications. First, these findings reassert the primacy of income level in capturing the salient economic circumstances for child development. I did not find many associations between income variability or trend and child development, and the scattered associations were many times smaller than those for income level. Importantly, this result was not because income level and variability or trend could not be distinguished conceptually or empirically (i.e., because of high collinearity), a fact that adds support to the idea that income level is more relevant to parental investment and family processes than changes in income.
Why might income level be more salient? One possibility is that even though income variability is high for some families, it is not disruptive because parents are able to predict when it will occur and respond in ways that protect the developmental contexts of children (e.g., consumption of basic needs and the quality of schools). This hypothesis would suggest that income level measured as an average over multiple years captures not only a family's overall economic circumstances but also the ways in which income shapes developmental contexts—for instance, through spending and stress. Also, the mostly null or small associations between income variability and trend and child achievement and behavior might be the result of observing income only yearly (or biyearly in some waves). Some prior studies indicated that intrayear income variability is more extreme than interyear variability and that changes in weekly or monthly income may be more stressful and disruptive to family routines (Gennetian et al. 2015). Further, attrition from the longitudinal PSID is known to be higher among those with unstable earnings (Fitzgerald et al. 1998), which may mean that this analysis does not include those with the most severe income instability. In part because of these data limitations, the results of this study should not dissuade ongoing scholarship on income dynamics, family processes, and children. There is good theoretical support for the idea that income variability and trend may matter to parental stress, spending on children, and child development (Hill et al. 2013; Sandstrom and Huerta 2013). In addition, prior studies found adverse effects of income variability on adolescent and adult education outcomes (Gennetian et al. 2018b; Gennetian et al. 2015; Hardy 2014). Finally, many low-income families face multiple types of instability simultaneously or regularly, including family instability, residential instability, and income instability. Perhaps the combined effects of those disruptions are more relevant to child development.
Second, the significant and larger adverse consequences of income variability for non-White children are particularly noteworthy. It is particularly important that race—not SES—moderated the effects of income variability in this study. Black and Hispanic children are more likely than White children to experience high income variability and low or no income growth (Hardy 2014; Hill 2018) and to experience greater adverse effects of income variability on school outcomes in adolescence (Gennetian et al. 2018b; Gennetian et al. 2015; Hardy 2014). Although developmental theory has long considered the intersecting contexts of race and class (García Coll et al. 1996), studies of the effects of race and class on child development are still likely to treat them as separate individual characteristics rather than as indicators of a child's position in systems of (dis)advantage. These intersecting disadvantages can alter the benefits that income confers, how income shapes the family and other developmental contexts, and the culturally adaptive practices used to support child development (García Coll et al. 1996; Henry et al. 2019). For example, the stress associated with racial discrimination (e.g., Pascoe and Richman 2009) could leave Black and Hispanic parents and children less able to weather the disruptions associated with income variability. Knowing that income dynamics matter differently for children of different racial/ethnic identities calls for more studies that capture the variation in context by race for same-SES families (e.g., Lindsay 2011), interactions between racial and class identities (e.g., Destin et al. 2019), and the differential value of parental investments in neighborhoods and schools (Reardon et al. 2015). A key question for future researchers is whether processes related to racial identity and racial discrimination make African American and Hispanic children more vulnerable or resilient to different types of instability.
Third, two suggestive and counterintuitive findings regarding the interaction between SES and income dynamics are worth noting. First, the association between income variability and achievement scores was negative for the higher-wealth families, although the interaction was not statistically significant. Also, the association of income growth with achievement tests was positive for those with above-median income or wealth but negative for families with below-median income or wealth (only the wealth interaction on math was statistically significant). These results may relate to how low- and high-SES families spend money on children. Prior studies found that income is related to child achievement development primarily through parental investments in care, education, and basic needs (Guo and Harris 2000; Yeung et al. 2002). Also, socioeconomic inequality in parental investments have been growing over time (e.g., Kornrich and Furstenberg 2013). Perhaps higher-SES families investing disproportionally more in children are less likely to experience income variability, but it is more likely for variability to affect their children. Also plausible is that year-to-year income changes are most disruptive for more financially stable families in the same way that recent studies have found that paternal incarcerations and maternal job loss are more disruptive for the families least likely to experience them (Brand and Thomas 2014; Turney 2015).
This study has several limitations. First, the small sample of the CDS constrained the analysis of subgroups or moderated effects. For example, most evidence on age as a moderator of the effects of income on child outcomes suggests that children under age 6 are most vulnerable, but this study's sample was not large enough to examine that group specifically. Also, as an observational study, the analysis presented here assumed that all differences between children in families with different income dynamics have been observed and included in the model and that there is no reverse causal relationship by which child achievement and behavior are influencing family income dynamics. Given these strong assumptions, the results should be viewed as associational, not causal. Finally, the measurements of child achievement and behavior are not without flaws. The test scores capture achievement, which is considered a proxy for cognitive development but one that is highly affected by contextual factors (e.g., the quality of schools), and parent-reported behavior measures are known to be biased negatively if the reporter is depressed (Chi and Hinshaw 2002; Gartstein et al. 2009). Importantly, it was beyond the scope of this study to identify the causes of income variability or to examine how the effects of income dynamics differ by different family structures, employment patterns, or public assistance use. These are topics ripe for future research.
Despite these limitations, the study adds to our growing understanding of the dynamic nature of family life and particularly the salience of instability in multiple domains for lower-SES families and children. It suggests that income variability and trend are distinct features of economic circumstances during the life course, although less consequential to this set of outcomes than income level. The larger associations between income level and child achievement (compared with those between income variability and child achievement) support the focus of income support programs (e.g., Supplemental Nutrition Assistance Program and Earned Income Tax Credit) on income sufficiency and basic needs. Nonetheless, these results suggest that interventions designed to support family income or wealth could benefit children by experimenting with delivering benefits in ways that promote both sufficiency and stability. Future research should focus on the mechanisms of the effects of income variability and trend on child development, particularly whether they differ from the established mechanisms of intergenerational class transmission. Both large surveys and community studies of child development could support future research by adding higher frequency measures of family economic circumstances, parenting stress and practices, and child well-being. Finally, future studies could help to disentangle the differing effects of income variability caused by different events in family life, including parental employment instability, family structure instability, and health events.
## Acknowledgments
The author thanks the Editor, Dr. Mark Hayward, and several anonymous reviewers for excellent feedback that improved this paper. In addition, the author thanks Chieko Maene at the University of Chicago, who provided research assistance during the early stages of this project, and the investigators and staff of the Panel Study of Income Dynamics at the Institute for Social Research at the University of Michigan. This research was partially supported by the Family Self-Sufficiency Research Consortium, Grant Number 90PD0290-03-00, funded by the Office of Planning, Research, and Evaluation in the Administration for Children and Families, U.S. Department of Health and Human Services; and by a Eunice Kennedy Shriver National Institute of Child Health and Human Development research infrastructure grant, P2C HD042828, to the Center for Studies in Demography & Ecology at the University of Washington. The contents of this publication are solely the responsibility of the author.
## Notes
1
I omit four CDS cases from this analysis because of a known error in their family’s income variables in the 1997 and 1999 PSID (Dynan et al. 2012).
2
In the PSID, the label of “head” is assigned to the adult in the family unit with financial responsibility. In families with a male spouse or partner present, the man is automatically assigned as the head unless he is incapacitated. The spouse or long-term cohabiting partner of the head is labeled the “wife.” Other adults in the household could be short-term cohabiting partners, extended family members, or unrelated individuals. Same-gender couples in the sample receive the same labels as different-gender couples, with one exception: same-gender couples are labeled “head” and “girlfriend/boyfriend” regardless of the length of the cohabitation, and different-gender couples are labeled as “head” and “wife” after they cohabit for one year.
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This is an open access article distributed under the terms of a Creative Commons license (CC BY-NC-ND 4.0).
| 2022-09-28T19:47:57 |
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|
https://www.usgs.gov/media/files/sulfur-2016-tables-only-release
|
# Sulfur in 2016, tables-only release
Sulfur in 2016, tables-only release
## Detailed Description
Advance data tables (XLSX format) for the sulfur chapter of the Minerals Yearbook 2016. A version with an embedded text document and also a PDF of text and tables will follow.
| 2021-07-24T02:33:18 |
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|
http://www.sandia.gov/~tgkolda/feastpack/bter.html
|
## Contents
function [e1,e2,info] = bter(nd,cd,varargin)
%BTER Generate edges for BTER model.
%
% [E1,E2] = BTER(ND,CD) generates a list of edges for the BTER model for
% the given degree distribution and clustering coefficients per degree,
% i.e., ND(d) = the number of nodes of degree d and CD(d) = mean
% clustering coefficient for degree d. The edge list E = [E1;E2] is a
% list of edges created by the BTER model from phases 1 and 2,
% respectively. The edge list will have duplicates, which can be remedied
% in post-processing.
%
% [E1,E2,INFO] = BTER(...) returns extra information.
%
% [...] = BTER(ND,CD,'param',value,...) takes a sequence of
% parameter-value pairs to specify the operation of the method
%
% - 'blowup' - Multiplier for number of degree-1 nodes. Default: 1.
% - 'rmloops' - Remove self-links. Default: true.
% - 'cleanup' - Clean-up degree-1 nodes per blowup. Default: true.
% - 'swap' - Swap edge endpoints so least is 1st. Default: false.
% - 'verbose' - Print information. Default: true.
% - 'rngseed' - Seed for the random number generator.
%
% References:
% * C. Seshadhri, T. G. Kolda and A. Pinar. Community structure and
% scale-free collections of Erdös-Rényi graphs, Physical Review E
% 85(5):056109, May 2012. (doi:10.1103/PhysRevE.85.056109)
% * T. G. Kolda, A. Pinar, T. Plantenga and C. Seshadhri. A Scalable
% Generative Graph Model with Community Structure, arXiv:1302.6636,
% March 2013. (http://arxiv.org/abs/1302.6636)
%
%
% Tamara G. Kolda, Ali Pinar, and others, FEASTPACK v1.1, Sandia National
% Laboratories, SAND2013-4136W, http://www.sandia.gov/~tgkolda/feastpack/,
% January 2014
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
% ** Check inputs
if nargin < 1
error('At least one input is required');
end
if nargout < 1
error('At least one output is required');
end
% ** Process inputs
params = inputParser;
params.parse(varargin{:});
beta = params.Results.blowup;
if beta < 1
error('Must have ''blowup'' >= 1.');
end
swap = params.Results.swap;
rmloops = params.Results.rmloops;
cleanup = params.Results.cleanup;
verbose = params.Results.verbose;
rngseed = params.Results.rngseed;
% Set random number generator
if isempty(rngseed)
rngseed = rng;
end
rng(rngseed);
% Input checking
dmax = length(nd);
if length(cd) ~= dmax
error('Inputs ND and CD must be the same length');
end
if any(nd < 0)
error('Degree distribution cannot be negative');
end
if any(round(nd) ~= nd)
error('Degree distribution must be integral');
end
if any(cd < 0) || any(cd > 1)
error('Clustering coefficients must be between 0 and 1');
end
% ** Setup
tic;
[id,wd,ndfill,rdfill,ig,wg,bg,ng] = bter_setup(nd, cd, beta);
time_setup = toc;
if (verbose)
fprintf('--- BTER HPC Set-up ---\n');
fprintf('Desired number of nodes: %d\n', sum(nd));
fprintf('Desired number of edges: %.0f\n', sum(nd.*(1:dmax)')/2);
fprintf('Multiplier to degree-1 nodes: %g\n', beta);
fprintf('Maximum degree: %d\n', dmax);
fprintf('Number of groups: %d\n', length(ig));
fprintf('Number of blocks: %d\n', sum(bg));
fprintf('Phase 1 total weight: %.0f\n', sum(wg));
fprintf('Phase 2 total weight: %.0f\n', sum(wd));
fprintf('Time for setup (sec): %.2f\n', time_setup);
end
% ** Determine number of samples per phase
tic;
w1 = sum(wg);
w2 = sum(wd);
w = w1+w2;
nsmp = round(w);
r = rand(nsmp,1);
s1 = sum(r < w1/w);
s2 = nsmp - s1;
time_split = toc;
if (verbose)
fprintf('Determined phase for %d edges in %f seconds\n', nsmp, time_split);
end
% ** Phase 1 Samples
tic;
grp_smp = random_sample(wg, s1);
blk_r = rand(s1,1);
blk_b = bg(grp_smp);
blk_i = ig(grp_smp);
blk_n = ng(grp_smp);
e1_shift = blk_i + floor(blk_r .* blk_b) .* blk_n;
e1_r = rand(s1,2);
e1(:,1) = floor(e1_r(:,1) .* blk_n) + e1_shift;
e1(:,2) = floor(e1_r(:,2) .* (blk_n - 1)) + e1_shift;
e1(:,2) = e1(:,2) + (e1(:,2) >= e1(:,1));
time_p1 = toc;
if (verbose)
fprintf('Sampled %d edges for phase 1 in %f seconds\n', s1, time_p1);
end
% ** Phase 2 Samples
tic;
% Setup
idfill = id;
idbulk = id + ndfill;
ndbulk = nd - ndfill;
ndbulk(1) = 0;
% Sample
d_smp = random_sample(wd, 2*s2);
d_smp = reshape(d_smp, s2, 2);
r = rand(s2,2);
tf_fill = r < rdfill(d_smp);
e2_shift_fill = idfill(d_smp);
e2_sz_fill = ndfill(d_smp);
e2_shift_bulk = idbulk(d_smp);
e2_sz_bulk = ndbulk(d_smp);
r = rand(s2,2);
e2_fill = e2_shift_fill + floor(r .* e2_sz_fill);
e2_bulk = e2_shift_bulk + floor(r .* e2_sz_bulk);
e2 = tf_fill .* (e2_fill) + ~tf_fill .* (e2_bulk);
time_p2 = toc;
if (verbose)
fprintf('Sampled %d edges for phase 2 in %f seconds\n', s2, time_p2);
end
% ** Remove loops (Phase 2 only)
if rmloops
tic;
tf = (e2(:,1) == e2(:,2));
e2 = e2(~tf,:);
time_rmloops = toc;
if (verbose)
fprintf('Removed %d loops in %f seconds\n', sum(tf), time_rmloops);
end
end
% ** Reorder edges so lower index is first
if swap
tic;
e1 = bter_swap(e1);
e2 = bter_swap(e2);
time_swap = toc;
if (verbose)
fprintf('Swapped low degree first in %f seconds\n', time_swap);
end
end
% ** Reindexing "degree-1" vertices to only keep those that have a link
if (beta > 1) && (cleanup)
tic;
idx = id(1); % Index of first degree-1 node
dtrue = accumarray(e2(:),1);
tf = ones(size(dtrue)) > 0;
tf(idx:end) = dtrue(idx:end) > 0;
n_old = length(dtrue);
n_new = sum(tf);
old2newidx = zeros(length(dtrue),1);
old2newidx(tf) = (1:n_new)';
e2 = old2newidx(e2);
time_cleanup = toc;
if (verbose)
fprintf('Removed %d spurious degree-1 nodes in %f seconds\n', ...
n_old - n_new, time_cleanup);
end
end
% ** Finishing up
if (verbose)
fprintf('--- BTER HPC Complete ---\n');
end
% Fill in INFO
if nargout >= 3
S = whos;
info = struct;
for i = 1:length(S);
var = S(i).name;
if (var(1) == 'e') || strcmp(var(1:min(3,end)),'blk') || ...
strcmp(var, 'old2newidx') || strcmp(var, 'd_smp') || ...
strcmp(var, 'grp_smp') || strcmp(var, 'tf') || ...
strcmp(var, 'dtrue') || strcmp(var, 'r') || ...
strcmp(var,'tf_fill')
continue;
end
eval(['info.' var ' = ' var ';']);
end
end
function edges = bter_swap(edges)
%BTER_SWAP Given a list of edges, make lower index first.
tf = edges(:,1) > edges(:,2);
tmp = edges(tf,2);
edges(tf,2) = edges(tf,1);
edges(tf,1) = tmp;
function [id,wd,ndfill,rdfill,ig,wg,bg,ng] = bter_setup(nd, cd, beta)
%BTER_SETUP Creates data for generating BTER graphs.
% Compute maximum degree
dmax = length(nd);
% Set up arrays (max # groups = dmax)
id = zeros(dmax,1); % i_d
wd = zeros(dmax,1); % w_d
rdfill = zeros(dmax,1); % r^{\rm fill}_d
ndfill = zeros(dmax,1); % n^{\rm fill}_d
wg = zeros(dmax,1); % w_g
ig = zeros(dmax,1); % i_g
bg = zeros(dmax,1); % b_g
ng = zeros(dmax,1); % n_g
% Index of first node for each degree.
% Degree 1 vertices are numbered last.
tmp = cumsum(nd(2:end));
id(2) = 1;
id(3:end) = tmp(1:end-1)+1;
id(1) = tmp(end)+1;
% Compute number of nodes with degree greater than d
tmp = flipud(cumsum(flipud(nd)));
ndprime = zeros(dmax, 1);
ndprime(2:end-1) = tmp(3:end);
% Handle degree-1 nodes
ndfill(1) = nd(1) * beta;
wd(1) = 0.5 * nd(1);
rdfill(1) = 1;
% Main loop
g = 0;
nfillblk = 0;
intdeg = 0;
for d = 2:dmax
if nfillblk > 0
ndfill(d) = min( nfillblk, nd(d) );
nfillblk = nfillblk - ndfill(d);
wdfilltmp = 0.5 * ndfill(d) * (d - intdeg);
else
ndfill(d) = 0;
wdfilltmp = 0;
end
ndbulktmp = nd(d) - ndfill(d);
if ndbulktmp > 0
g = g + 1;
ig(g) = id(d) + ndfill(d);
bg(g) = ceil(ndbulktmp / (d+1));
ng(g) = d+1;
if (bg(g) * (d+1)) > (ndprime(d) + ndbulktmp)
if bg(g) ~= 1
error('Last group has more than 1 block');
end
ng(g) = ndprime(d) + ndbulktmp;
end
rho = nthroot(cd(d), 3);
intdeg = (ng(g) - 1) * rho;
wdbulktmp = 0.5 * ndbulktmp * (d - intdeg);
wg(g) = bg(g) * 0.5 * ng(g) * (ng(g) - 1) * log (1/(1-rho));
nfillblk = bg(g) * ng(g) - ndbulktmp;
else
wdbulktmp = 0;
end
wd(d) = wdbulktmp + wdfilltmp;
if (wd(d) > 0)
rdfill(d) = wdfilltmp / wd(d);
else
rdfill(d) = 0;
end
end
% Shorten the group arrays
ig = ig(1:g);
wg = wg(1:g);
bg = bg(1:g);
ng = ng(1:g);
| 2014-10-02T10:29:48 |
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|
https://www.usgs.gov/news/volcano-watch-island-castaways
|
# Volcano Watch — Island Castaways
March 16, 2000
The home of over 5 million breeding seabirds, Laysan Island is an uninhabited Hawaiian atoll formed from coral deposits atop a 20 million-year-old submerged volcano. Today the highest point of what was once "Laysan Mountain" is only about 12 meters (40 feet) above sea level, and a person can walk the perimeter in about 3 hours.
The home of over 5 million breeding seabirds, Laysan Island is an uninhabited Hawaiian atoll formed from coral deposits atop a 20 million-year-old submerged volcano. Today the highest point of what was once "Laysan Mountain" is only about 12 meters (40 feet) above sea level, and a person can walk the perimeter in about 3 hours. The interior of the island holds a large, salty lake 2-4 times the salinity of the ocean and full of bright pink brine shrimp. Mudflats surround the lake and in the springtime are covered with clouds of small flies. The interior of the island is vegetated with native bunch grasses.
By day, the small, endangered Laysan Duck hides in the thick grass and is invisible to both the soaring seabirds overhead and the researchers who study them. The glossy brown ducks with spectacle-like white eye-rings emerge from their hiding places before sunset and congregate at the lake or coastal tidepools. Some begin feeding in the vegetation or on the shrimp and flies around the lake. They disappear into the bunch grasses again before dawn.
About 90 years ago there were no bunch grasses left on the island, after rabbits were introduced in the early 1900s and ate all the vegetation. This catastrophe brought the Laysan Duck to the brink of extinction. The species miraculously recovered from a population of less than 10 adults, when the rabbits were eliminated and the vegetation grew back. Unfortunately, three other landbirds, the Laysan Rail, Laysan Millerbird, and Laysan Apapane did not survive, due to the damage caused by the rabbits. Laysan has been designated as a National Wildlife Refuge since 1909, and the ducks were among the original endangered species listed in 1964 because of the threat of their extinction. Today there are fewer than 400 wild Laysan Ducks, found only on Laysan Island.
The Laysan Duck has the most restricted range of any duck species. Although they can fly, they don't leave the island, even when there is a drought, a big storm, or a disease epidemic. Perhaps Laysan is the safest place to be, because there are no mammalian predators there. Like many of Hawaii's species, the Laysan Duck evolved without rats, cats, and mongooses and is ill-suited to a habitat invaded by non-native predators. The ducks are very curious and will approach humans for a closer look.
The effects of human-caused change have been most severe for island birds. Until 1995, the Laysan Duck was thought to have inhabited only the island for which it was named. However, paleontologists have recently discovered remains of Laysan Ducks from Lisianski, Kauai, Oahu, Molokai, Maui, and Hawaii.
Bones from adult and flightless juvenile Laysan Duck have been found at many diverse areas on Hawaii Island, including higher elevations of Hualālai, Mauna Kea, and Mauna Loa. Remains were also found in lower elevations near the coast at South Point. It is likely that Laysan Ducks inhabited all the islands of the chain. Perhaps the ducks flew between the Hawaiian Islands until the risk of dispersing increased after the arrival of humans and other mammals; those flying between islands did not survive. Thus, the Laysan Duck has been restricted to Laysan Island only since the time period between 1840 and 1890!
Isolated populations are extremely vulnerable to extinction from chance events and human-caused disturbance. The population on nearby Lisianski Island vanished after successive shipwrecks on the island in the 1840s. The Laysan Duck has been missing from the main Hawaiian Islands for only about a thousand years. The fossil evidence has revealed that the Laysan Duck is essentially an island castaway. Perhaps it could be restored to other predator-free islands.
### Volcano Activity Update
Eruptive activity of Kīlauea Volcano continued unabated during the past week, and a glow from Puu Oo crater was visible at various times. Lava is erupting from Puu Oo and flowing through a network of tubes toward the coast. Occasional breakouts from the tube system above and on the face of Pulama pali produce short-lived aa and pahoehoe lava flows. One flow is entering the ocean at Laeapuki, and a second flow, located to the east of the first flow, is active in the area near Wahaula. The public is reminded that the ocean-entry areas are extremely hazardous, with explosions accompanying unpredictable collapses of the new land. The active lava flows are hot and have places with very thin crust. The steam clouds are highly acidic and laced with glass particles.
There were two earthquakes reported felt during the week ending on March 16. Residents of Hilo felt an earthquake at 4:56 a.m. on March 10. The magnitude-3.3 temblor was located 12 km (7.2 miles) southeast of the summit of Kīlauea Volcano at a depth of 7.9 km (4.7 miles). The second earthquake was reported felt by residents of Honaunau at 11:04 p.m. on March 13. The magnitude-2.4 earthquake was located 4 km (2.4 miles) south Of Honaunau at a depth of 13.6 km (8.1 miles).
| 2022-06-26T03:17:24 |
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|
https://etl.beis.gov.uk/products/heating-ventilation-air-conditioning-hvac/evaporative-air-coolers
|
# Evaporative Air Coolers
## 1.1 Scope
Evaporative air coolers can be direct or indirect. With direct evaporative air cooling, outside air is blown through a water-saturated medium and cooled by evaporation. The cooled air is circulated by a fan. With indirect evaporative air cooling, a secondary air stream is cooled by water. The cooled secondary air stream passes through a heat exchanger, where it cools the primary air stream. The cooled primary air stream is circulated by a fan.
Evaporative air coolers are available with a wide variety of efficiencies. The Energy Technology List (ETL) Scheme aims to encourage the purchase of direct evaporative air coolers and higher efficiency indirect evaporative air coolers.
The ETL Scheme covers two categories of product:
1. Direct evaporative air coolers
2. Indirect evaporative air coolers
To be eligible for inclusion on the ETL, products shall meet the requirements as set out below.
## 1.2 Definitions
An evaporative air cooler is a device that cools air through the evaporation of water.
## 1.3 Requirements
### 1.3.1 Eligibility requirements
General functional criteria for evaporative air coolers
Direct and Indirect evaporative air coolers shall conform to the following functional criteria:
• Incorporate one or more electrically powered fans
• Incorporate an electrically powered pump to circulate water to a water-saturated medium through which an air stream passes or to spray nozzles in an air stream.
• Minimise scale build up with optimised water bleed rates
• Maintains conditions compliant with ACoPl8 legionella code of practice and guidance.
• Not use air to cool a water stream.
Direct and indirect evaporative air coolers shall be have an appropriate Conformity Assessment mark.
In addition to the general functional criteria above, evaporative air coolers shall also conform to specific functional criteria for either direct or indirect evaporative air coolers.
Functional criteria for direct evaporative air coolers:
In order for the product to be classified as a direct evaporative air cooler, all of the following criteria shall be met:
• The product cools an air stream by moving air through a water-saturated medium which is cooled by evaporation. Moisture must be added to the air stream until it is close to the point of saturation (i.e., the wet bulb depression is close to zero).
• The product dry bulb temperature should reduce while the wet bulb temperature remains constant.
Functional criteria for indirect evaporative air coolers:
The product will be classified as an indirect evaporative air cooler should any one of the following criteria be met:
• The product incorporates a secondary air stream that is cooled by means of evaporation of water.
• The product incorporates a secondary air stream that passes through a heat exchanger in order to provide further cooling to a primary air stream.
• The product incorporates a primary airstream with no change in absolute moisture content.
### 1.3.2 Performance requirements
Eligible indirect evaporative air coolers shall meet the following criteria:
1. Energy Efficiency Ratio (EER). The EER is the ratio of cooling capacity (kW) to electrical power input (kW).
$$EER=\frac{Cooling\ capacity\ (kW)}{electrical\ power\ input\ (kW)}$$
$$Cooling\ capacity,\ q=1.21Q_p(t_{d1}-t_{d2})$$
td1 and td2 are the primary air inlet and outlet dry-bulb temperatures, respectively.
Qp is the primary standard airflow rate (m3/s).
The total electric power input is the sum of pump, air-moving device, and any other electric power input due to appurtenances required to produce cooling.
Table 1.1 EER performance threshold for indirect evaporative air coolers
Product category EER
Indirect ≥7.0
'≥' means 'greater than or equal to'
2. Cooling Effectiveness (ε), which is the primary air dry-bulb temperature reduction divided by the primary air entering dry-bulb temperature less the entering secondary air wet-bulb temperature.
$$Ɛ=\frac{t_{d1}-t_{d2}}{t_{d1}-t_{w3}}$$
Where, tw3 is the secondary air inlet wet bulb temperature.
Table 1.2 Cooling effectiveness performance threshold for indirect evaporative air coolers
Product category Cooling effectiveness (%)
Indirect ≥95.0
'≥' means 'greater than or equal to'
3. Water consumption. For information purposes only, provide details on the amount of water consumed by the indirect evaporative cooling unit (m3/hr).
## 1.4 Measurement and Calculations
### 1.4.1 Measurement standards
All indirect evaporative air coolers shall be tested in accordance with the procedures and test conditions laid down in:
ANSI/ASHRAE Standard 143-2015: Method of Test for Rating Indirect Evaporative Coolers.
### 1.4.2 Calculation Requirements
The EER and cooling effectiveness of the evaporative air cooler will be calculated when operated at an inlet psychometric condition of 35°C dry bulb temperature, and a 24°C wet bulb temperature. Furthermore, the following external resistance (system static pressure) will be applied:
• Units up to 4 m3/s = 80 Pa resistance
• Units greater than 4 m3/s = 120 Pa resistance
### 1.4.3 Rounding
For the avoidance of doubt test data should be presented to 1 decimal place. As an example, a Cooling Effectiveness of 94.9 % for an indirect unit would be deemed to be a fail.
## 1.5 Verification for ETL Listing
Any of the following testing routes may be used to demonstrate the conformity of products against the requirements:
• Witnessed testing
• Independent testing
• Representative testing (see clause 1.5.1)
Further information regarding the first two routes can be found in Guidance Note 5 on the ETL product testing framework .
### 1.5.1 Representative testing
Where applications are being made for a range of two or more products that are variants of the same basic design, test data may be submitted for a representative selection of models, provided that it can be demonstrated that all variants:
• Utilise the same core technology as the tested model;
• Utilise the same key components as the tested model.
The representative models must be selected by dividing the range of products into groups of models with similar design characteristics, and testing a model in the lowest quartile of predicted performance in each group. The performance of each model in the group must be predicted using a validated mathematical model. As a minimum, at least one model must be tested in each range of products.
It should be noted that:
• If a manufacturer voluntarily removes the representative model from the ETL then other products linked with that representative model may or may not be permitted to remain on the ETL.
• If any product submitted under these representative model rules is later found not to meet the performance criteria when independently tested, then all products based on the same representative model will be removed from the ETL.
## 1.6 Conformity testing
Products listed on the ETL may be subject to the scheme’s conformity testing programme in order to ensure listed models continue to meet the ETL requirements.
| 2023-02-01T16:36:21 |
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|
http://dlmf.nist.gov/10.42
|
# §10.42 Zeros
Properties of the zeros of $\mathop{I_{\nu}\/}\nolimits\!\left(z\right)$ and $\mathop{K_{\nu}\/}\nolimits\!\left(z\right)$ may be deduced from those of $\mathop{J_{\nu}\/}\nolimits\!\left(z\right)$ and $\mathop{{H^{(1)}_{\nu}}\/}\nolimits\!\left(z\right)$, respectively, by application of the transformations (10.27.6) and (10.27.8).
For example, if $\nu$ is real, then the zeros of $\mathop{I_{\nu}\/}\nolimits\!\left(z\right)$ are all complex unless $-2\ell<\nu<-(2\ell-1)$ for some positive integer $\ell$, in which event $\mathop{I_{\nu}\/}\nolimits\!\left(z\right)$ has two real zeros.
The distribution of the zeros of $\mathop{K_{n}\/}\nolimits\!\left(nz\right)$ in the sector $-\tfrac{3}{2}\pi\leq\mathop{\mathrm{ph}\/}\nolimits z\leq\tfrac{1}{2}\pi$ in the cases $n=1,5,10$ is obtained on rotating Figures 10.21.2, 10.21.4, 10.21.6, respectively, through an angle $-\tfrac{1}{2}\pi$ so that in each case the cut lies along the positive imaginary axis. The zeros in the sector $-\tfrac{1}{2}\pi\leq\mathop{\mathrm{ph}\/}\nolimits z\leq\tfrac{3}{2}\pi$ are their conjugates.
$\mathop{K_{n}\/}\nolimits\!\left(z\right)$ has no zeros in the sector $|\mathop{\mathrm{ph}\/}\nolimits z|\leq\tfrac{1}{2}\pi$; this result remains true when $n$ is replaced by any real number $\nu$. For the number of zeros of $\mathop{K_{\nu}\/}\nolimits\!\left(z\right)$ in the sector $|\mathop{\mathrm{ph}\/}\nolimits z|\leq\pi$, when $\nu$ is real, see Watson (1944, pp. 511–513).
For $z$-zeros of $\mathop{K_{\nu}\/}\nolimits\!\left(z\right)$, with complex $\nu$, see Ferreira and Sesma (2008).
See also Kerimov and Skorokhodov (1984b, a).
| 2016-07-31T03:33:26 |
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|
https://www.usgs.gov/congressional/statement-dr-david-applegate-associate-director-natural-hazards-us-geological-survey
|
# Statement of Dr. David Applegate, Associate Director for Natural Hazards, U.S. Geological Survey
July 29, 2014
Before the House Committee on Science, Space, and Technology, Subcommittee on Research and Technology, on the National Earthquake Hazards Reduction Program
Chairman Bucshon, Congressman Lipinski, Members of the Subcommittee, thank you for inviting the U.S. Geological Survey (USGS) to testify at this hearing on the National Earthquake Hazards Reduction Program (NEHRP). The USGS is proud to be a partner in NEHRP, which is led by the National Institute of Standards and Technology (NIST) and includes the Federal Emergency Management Agency (FEMA) and the National Science Foundation (NSF). We greatly appreciate the collective opportunity to provide you a comprehensive update on NEHRP, a highly successful partnership that continues to make valuable contributions to the Nation's resilience to earthquakes.
NEHRP is predicated on the belief that while earthquakes are inevitable, their consequences are not, and there is much that we can do as a Nation to improve public safety and our resilience to earthquakes and related hazards. Within NEHRP each agency performs a distinct and complementary role essential for the overall success of the program. The program is conducted with a high degree of cooperation and collaboration without competition for responsibilities or resources. The heart of this partnership is a broadly shared commitment to translate research results into implementation actions that can reduce earthquake losses. That commitment involves collaboration that goes beyond the four agencies to include other Federal partners, plus State, Tribal and local governments, universities, and the private sector.
USGS NEHRP Activities
Carrying out its role within NEHRP, the USGS strives to deliver the data and information tools that engineering and design professionals, emergency managers, government officials and the public need to prevent earthquake hazards from becoming earthquake disasters. USGS activities supporting NEHRP are implemented through our Earthquake Hazards Program (EHP) and Global Seismographic Network (GSN) Programs. With its partners, the USGS provides rapid and authoritative information on earthquake size, location, shaking intensity, and potential impacts; develops regional and national hazard assessment maps and related products; supports targeted research to improve our monitoring and assessment capabilities; and builds public awareness of earthquake hazards. In what follows, I discuss the current status of these activities.
Earthquake Monitoring - Delivering Rapid Information for Emergency Response. The USGS provides rapid reports of potentially damaging earthquakes to the White House; the Departments of Defense, Homeland Security (including FEMA), State, Transportation, Energy, Commerce, and the Interior; State, Tribal, and local emergency managers; numerous public and private infrastructure management centers (for example railroads and pipelines); the news media; and the public. Over 430,000 people in the United States and around the world have signed up to receive earthquake notifications via e-mail or text message. The suite of information tools available through the USGS Earthquake Hazards Program website receives tens of millions of hits in the wake of damaging earthquakes.
The USGS Advanced National Seismic System (ANSS) is the technical foundation that allows delivery of these products. The 2000 reauthorization of NEHRP established the ANSS to modernize and expand the Nation’s seismic monitoring infrastructure in order to improve the delivery of earthquake information to those who need it most. The ANSS consists of a national backbone network, regional networks operated by State and university partners, the USGS National Earthquake Information Center (NEIC), and ground- and structure-based instruments concentrated in high-hazard urban areas. With funding appropriated by Congress since 2000, the USGS and its partners have installed more than 2,800 new and upgraded stations, out of a total of 7,100 targeted in the ANSS plan for full implementation of the system (USGS Circular 1188). The USGS also initiated 24/7 on-site operations at NEIC in 2006 and supports development of new information tools for enhanced situational awareness such as the ShakeCast, Prompt Assessment of Global Earthquakes for Response (PAGER), and Tweet Earthquake Dispatch (TED) systems (see earthquake.usgs.gov for details). These investments have greatly improved the information available for emergency responders, engineering performance studies, and long-term earthquake hazard assessments. A 2005 report by the National Research Council on the costs and benefits of improved seismic monitoring found that the benefits of fully deploying ANSS outweigh the costs many times over.
Substantial improvements in ANSS infrastructure were realized in 2010 and 2011 as a result of economic stimulus funding. The USGS allocated $19 million of the$140 million dollars it received under the American Recovery and Reinvestment Act (ARRA) to the modernization component of ANSS. Outdated equipment at hundreds of legacy seismic stations was replaced with modern digital equipment. Funds were also used to upgrade communications and processing software and to develop critical software components for the system as a whole. ARRA funding was allocated to 13 cooperating State and university partners that performed the station and network upgrades
Assessing the Nation’s Earthquake Hazards. Earthquakes are a national challenge, with about 142 million people living in moderate- to high-hazard areas stretched across 42 States. Recent earthquakes in Colorado, Oklahoma, and Virginia have underscored the national nature of earthquake risk. One of the most important achievements that NEHRP has made is the translation of research into national models of the location and expected severity of earthquake shaking within specified time periods. These models are used to generate maps that are incorporated into the seismic safety elements of building codes and for other purposes. Each major update of the maps is the culmination of a multi-year process to incorporate the best available science, including geologic information about faults, evidence of prehistoric earthquakes, instrumental and historical earthquake catalogs generated by seismic monitoring, and ground deformation measurements.
Earlier this month, the USGS released the latest update of the National Seismic Hazard Maps reflecting the current state of understanding. The release of the updated seismic hazard maps is coordinated with the consequent release of the next generation of model building codes and seismic safety standards, a process that involves close cooperation among the USGS, FEMA, the Building Seismic Safety Council, the American Society of Civil Engineers, the International Code Council, and other organizations. The 2014 maps have now been approved by the NEHRP Recommended Seismic Provisions Update Committee of the Building Seismic Safety Council, a major step towards incorporation into the International Building Code and International Residential Code, which is adopted in almost all States. The maps are also used by insurance companies to set rates for properties, by civil engineers to estimate the stability and landslide potential of hillsides, by the U.S. Environmental Protection Agency to set construction standards that ensure the safety of waste-disposal facilities, and by FEMA to plan the allocation of assistance funds for earthquake education and preparedness. The USGS also works closely with the U.S. Nuclear Regulatory Commission on seismic safety of nuclear power plants, including review of seismic hazard assessments in license applications.
Complementing the national maps, urban seismic hazard maps provide more detailed information on local site conditions for use in engineering and planning. Urban seismic hazard maps have been released for Memphis, Seattle, and Evansville (Indiana), and are near completion for the St. Louis area. Those maps show how forecasted earthquake shaking levels vary, at scales useful for urban planning, earthquake response planning, engineering guidance for major structures, and public education. Such maps require detailed mapping of surficial geology and knowledge of subsurface geology in order to incorporate the local effects into estimates of shaking. Developing these maps would not be possible without significant involvement of local and regional scientists, engineers, emergency managers, and the business community.
Targeted Research. USGS assessment and monitoring activities depend on targeted geoscience research. USGS internal research is augmented by external research supported by the USGS through grants to and cooperative agreements with universities, State geological surveys, and geotechnical consultants. Proposals for external work are submitted in response to an annual solicitation that identifies the scientific problems on which the USGS seeks assistance and progress. Each proposal undergoes a rigorous peer-review process. This targeted research is funded on the basis of merit and provides a bridge from the NSF’s investments in fundamental research in order to generate critical advances in understanding that underpin development of the national and urban seismic hazard maps and rapid earthquake response products. Ongoing collaboration with the academic community is one of the great strengths of the USGS with regard to earthquake research. Key examples are the jointly USGS-NSF supported Southern California Earthquake Center (SCEC) and our important partnership with the NSF’s EarthScope facility.
Using Earthquake Outreach and Education to Better Prepare. The USGS works to make earthquake hazards understood through education and outreach products developed in concert with NEHRP, university, and local government partners, including the FEMA-supported regional earthquake consortia; the NSF-supported IRIS consortium; and the SCEC university and government consortium. Millions of copies of earthquake preparedness handbooks have been distributed in Alaska, California, Tennessee, Utah, and many other states. As part of an effort to reach non-English-speaking populations, both the southern California and Bay Area versions of Putting Down Roots in Earthquake Country have been translated into Spanish, and a shortened version of the Bay Area Putting Down Roots has been translated into a number of Asian languages and distributed through Asian-language newspapers. Additional versions of Putting Down Roots have been developed for Utah and Idaho, and a version for the Central United States was published for the bicentennial commemoration of the New Madrid sequence of earthquakes that struck the heartland in the winter of 1811-12.
This past October, nearly 25 million people participated in the United States and around the world in the sixth annual Great ShakeOut earthquake drills – a public participation exercise in earthquake awareness and safety. The first ShakeOut, in 2008, was based on a comprehensive, science-based earthquake scenario for the impacts of a major rupture of the southern section of the San Andreas Fault; this formed the basis for the Great Southern California ShakeOut, involving over 5 million people. Through the leadership of SCEC and many others, the ShakeOut approach has been adopted by all 50 U.S. States and several territories as well as several foreign countries, and annual ShakeOuts have led to a number of positive outcomes, including efforts to reduce lifeline vulnerability, retrofit critical structures, improve monitoring systems, and educate residents. More generally, scenarios have proven to be powerful tools for making earthquake hazards real to people ahead of a disaster. The USGS recently entered into a partnership with the City of Los Angeles to use the vulnerabilities identified in the ShakeOut scenario to guide the city’s overall resilience efforts.
Post-earthquake coordination and investigations
Following major earthquakes in the United States and abroad, detailed scientific and engineering investigations are carried out in order to improve our knowledge of earthquake processes and impacts in order to hone the nation’s earthquake resilience. The 2004 authorization of NEHRP (P.L. 108-360) tasks the USGS with responsibility for coordinating post-earthquake investigations. The legislation required analysis by NSF and USGS of the causes of the earthquake and the nature of the resulting ground motion, analysis by NSF and NIST of the behavior of structures and lifelines, both damaged and undamaged, and analysis by each NEHRP agency of the effectiveness of the earthquake hazards mitigation programs and actions relating to its area of responsibility, and of how those programs and actions could be strengthened.
The USGS has carried out its post-earthquake coordination responsibility using the guidelines established in USGS Circular 1242, The Plan to Coordinate NEHRP Post-Earthquake Investigations, which was developed by the NEHRP agencies and other partners. Since 2010, the USGS has responded to and coordinated the national scientific and technical response for U.S. earthquakes in Arkansas, Colorado, Oklahoma, and Virginia as well as overseas in Chile, Haiti, Japan, Mexico, New Zealand, and Turkey.
The earthquakes that struck Haiti and Chile in 2010 and Japan in 2011 were some of the most devastating in recent history, and the shaking from the Virginia earthquake in 2011 was felt by more people than any previous earthquake in U.S. history. Each of these responses required immediate action by USGS staff, who were diverted from other work, often for weeks or months. Immediate demands included briefings for government officials and responses to the media. The USGS rapidly organized community-wide conference calls to coordinate the scientific and engineering response by Federal, State, university, and other institutional interests. All of the geospatial data collection was coordinated by the USGS. For each of the domestic earthquakes, the USGS deployed either portable seismometers to record aftershocks, or teams of geologists to conduct field studies, or both. For larger foreign earthquakes (Haiti, Chile, Japan, New Zealand), NEHRP agencies sent reconnaissance teams followed by more substantial deployments of USGS/USAID Earthquake Disaster Assistance Teams with portable seismometers and geologic expertise, as well as NSF-supported engineering teams, to determine the causes of building and ground failures.
Opportunities to further reduce earthquake losses in the United States
The Administration’s 2015 budget requests $59 million for the USGS’ two NEHRP Programs; this is slightly above the FY 2014 level. The proposed budget continues the initiatives that Congress supported in FY 2014: for the further development of an earthquake early warning system, for research on induced seismicity, and for improved ANSS products for situational awareness. The additional funding provided in FY 2014 and FY 2015 allows the USGS to build in these areas, particularly after facing budget reductions due to sequestration in FY 2013. Earthquake Early Warning: The next advance in public safety Modern seismic networks can, in favorable circumstances, provide seconds to a minute or more of warning before the onset of strong shaking, enabling Earthquake Early Warning (EEW). Over the past 11 years, the USGS has invested nearly$10 million in both research and development toward establishing an earthquake early warning capability in California. Funds from the 2009 American Recovery and Reinvestment Act were used in 2010 and 2011 to support the modernization of seismic instrumentation necessary to support the generation of warnings. A test system is operating now; two of the university partners (CalTech and the University of California Berkeley) have been delivering warnings to a small group of test users since January 2011.
The current test system is still in the development phase, however, and considerable additional testing and equipment deployment is required to create a robust and reliable operational warning system. Further work is needed to demonstrate reliability, improve accuracy, establish products for public warning, and expand geographic coverage. The additional funding for EEW that was appropriated by Congress in FY 2014 is being used to complete the R&D phase for the seismic system (an effort that is jointly supported by the Gordon and Betty Moore Foundation) and to improve the operational robustness of the system. The next steps will require expanding coverage throughout California, Oregon, and Washington, integrating global positioning system (GPS) technology into the EEW system, and operating the system continuously on a 24x7 basis.
Induced Seismicity. Potentially damaging earthquakes can be triggered by disposal of waste fluids from oil and gas production operations by injection into deep underground wells. Smaller earthquakes can also be triggered by enhanced geothermal energy production operations and, potentially, by deep geologic carbon sequestration. Although the basic geophysical mechanisms are well known, the specific subsurface conditions that are conducive to triggering are not, and it is not yet possible to make site-specific hazard predictions in advance. Thus, there is a need for more data and research on induced seismicity, to understand how these events may depend on specific operational parameters and geologic conditions and to develop monitoring and mitigation plans for decision-makers attempting to minimize seismic risks.
With the support of Congress and the Administration, the USGS is now working with the Department of Energy and the Environmental Protection Agency to undertake this research and working with industry on case studies that will illuminate the physical factors controlling induced earthquakes. Top-priority efforts are to develop methods to forecast whether or not a particular type of injection operation in a specified geologic setting would be likely to induce or trigger earthquakes, to perform comprehensive studies at two field sites, and to establish procedures to adapt the National Seismic Hazard Maps to take account of the additional hazard due to earthquakes induced in association with wastewater from the production of oil and gas.
NEHRP’s Global Reach
The Global Seismographic Network—a program involving the USGS, the National Science Foundation, and the Incorporated Research Institutions for Seismology, IRIS)—provides worldwide coverage for monitoring of earthquake and non-earthquake seismic activity, and supports basic and applied research in Earth science. GSN data are also critical to the NOAA tsunami warning system (and the tsunami warning systems of other nations) and support research on nuclear explosion detection and treaty verification.
With support from Congress in 2005, and again in 2009 under ARRA, the USGS and NSF have made significant progress maintaining the GSN at a state-of-the-science level, expanding real-time communications throughout the 150-station network and upgrading and standardizing the computers and other components at each station site. Even so, many GSN stations are now more than 20 years old. In 2012, Congress provided additional funding to the Department of Energy (DOE) to replace aging and failed seismic sensors and, under an agreement with DOE, the USGS is currently procuring those new sensors. The USGS and DOE are exploring options to fund installation of the new equipment.
Conclusion
The Department strongly supports reauthorization of NEHRP. It has proven to be a successful partnership that continues to make valuable contributions to the Nation's resilience to earthquakes and other hazards.
Thank you, Chairman Bucshon, for the opportunity to provide the Subcommittee with the USGS views on NEHRP. I would be pleased to answer any questions the Subcommittee may have.
| 2022-05-21T04:22:43 |
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https://www.nist.gov/ncnr/spin-filters/spin-filter-instruments/triple-axis/triple-axis-polarized-setup
|
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# TRIPLE AXIS POLARIZED SETUP
## STANDARD SETUP
SEQUENCE NAME DESCRIPTION
PB_polarizesetup.seq.txt This creates all the devices and opens Python communication with the 3He instrument rack. This must be done at the beginning of the experiment.
PB_Qmode.seq.txt This sets the sample and guide field currents for P $$\parallel$$ Q.
PB_Vmode.seq.txt This sets the sample and guide field currents for P $$\perp$$ Q.
PB_polarizeddestroy.seq.txt
This destroys all the devices and closes Python communication with the 3He instrument rack. This must be done at the end of the experiment.
NOTE: If the server re-starts, destroy all devices first and then run the sequence file to create devices.
## 7T SCM SETUP
SEQUENCE NAME DESCRIPTION
PB_polarizesetup7T.seq.txt This creates all the devices and opens Python communication with the 3He instrument rack. This must be done at the beginning of the experiment.
PB_SC7TGuides.seq.txt This sets the guide field currents for P $$\perp$$ Q.
PB_polarizeddestroy7T.seq.txt This destroys all the devices and closes Python communication with the 3He instrument rack. This must be done at the end of the experiment.
NOTE: If the server re-starts, destroy all devices first and then run the sequence file to create devices.
## NSF CELL FLIPPING
SEQUENCE NAME DESCRIPTION
PB_OffOff.seq.txt This corresponds to the 'A' state.
PB_ONOff.seq.txt This corresponds to the 'B' state.
PB_OffON.seq.txt This corresponds to the 'C' state.
PB_ONON.seq.txt This corresponds to the 'D' state.
## Contacts
Created February 19, 2019, Updated November 15, 2019
| 2023-03-21T11:07:23 |
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https://opentextbc.ca/physicalgeology2ed/back-matter/appendix-3-answers-to-exercises/
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# Appendix 3: Answers to Exercises
The following are suggested answers to the exercises embedded in the various chapters of Physical Geology. Answers to the chapter-end review questions are provided in Appendix 2.
# Chapter 1
## Exercise 1.1 Find a piece of granite
Responses will vary, but your sample should look something like the one shown below. Granitic rocks are hard and strong and difficult to break. They are dominated by feldspar (this one has both white plagioclase and pink potassium feldspar), but almost all have some quartz (which looks glassy) and a few dark minerals, like the black amphibole in this one.
## Exercise 1.2 Plate motion during your lifetime
It depends where you live of course, but if you live anywhere in Canada and anywhere in the US east of the San Andreas fault, then you’re on the North America Plate, and that is moving towards the west at 2 to 2.5 cm/year. So if you’re around 20 years old, that plate has moved between 40 and 50 cm to the west in your lifetime.
## Exercise 1.3 Using geological time notation
1. 2.75 ka is 2,750 years.
2. 0.93 Ga is 930,000,000 years or 930 million years.
3. 14.2 Ma is 14,200,000 years or 14.2 million years.
## Exercise 1.4 Take a trip through geological time
1. The oxygenation of the atmosphere started at around 2.5 Ga (2500 Ma). It was a catastrophe for many organisms because they could not survive the strong oxidizing effects of free oxygen.
2. We don’t really know the answer to this, but it’s not very long if you include insects, and there is evidence of insect damage to some of the earliest plants.
3. Plants on land allowed for animals on land, so without land plants, we wouldn’t be here.
# Chapter 2
## Exercise 2.1 Cations, anions and ionic bonding
Lithium (3) Magnesium (12) Argon (18) Chlorine (17) Beryllium (4) Oxygen (8) Sodium (11)
2 in shell one and 1 in shell two 2 in shell one, 8 in shell two and 2 in shell three 2 in shell one, 8 in shell two and 8 in shell three 2 in shell one, 8 in shell two and 7 in shell three 2 in shell one and 2 in shell two 2 in shell one and 6 in shell two 2 in shell one, 8 in shell two and 1 in shell three
It loses an electron and becomes a +1 cation It loses two electrons and becomes a +2 cation It is electronically stable, and does not become an ion It gains an electron and becomes a -1 anion It loses two electrons and becomes a +2 cation It gains two electrons and becomes a -2 anion It loses an electron and becomes a +1 cation
## Exercise 2.2 Mineral groups
Name Formula Group
sphalerite ZnS sulphide
magnetite Fe3O4 oxide
pyroxene MgSiO3 silicate
anglesite PbSO4 sulphate
sylvite KCl halide
silver Ag native
fluorite CaF2 halide
ilmenite FeTiO3 oxide
siderite FeCO3 carbonate
feldspar KAlSi3O8 silicate
sulphur S native
xenotime YPO4 phosphate
## Exercise 2.3 Make a tetrahedron
Responses will vary.
## Exercise 2.4 Oxygen deprivation
Single chain silicate: 1:3 (silicon to oxygen). Double chain silicate: 7:19 (or 1:2.71)
## Exercise 2.5 Ferromagnesian silicates
Mineral Formula Ferromagnesian Silicate?
olivine (Mg,Fe)2SiO4 yes
pyrite FeS2 no (it’s a sulphide, not a silicate)
plagioclase CaAl2Si2O8 no
pyroxene MgSiO3 yes
hematite Fe2O3 no (it’s an oxide, not a silicate)
orthoclase KAlSi3O8 no
quartz SiO2 no
amphibole Fe7Si8O22(OH)2 yes
muscovite K2Al4 Si6Al2O20(OH)4 no
magnetite Fe3O4 no (it’s an oxide, not a silicate)
biotite K2Fe4Al2Si6Al4O20(OH)4 yes
dolomite (Ca,Mg)CO3 no (it’s a carbonate, not a silicate)
garnet Fe2Al2Si3O12 yes
serpentine Mg3Si2O5(OH)4 yes
# Chapter 3
## Exercise 3.1 Rock around the rock-cycle clock
Sedimentary rock is buried deeper to make metamorphic rock, the metamorphic rock is uplifted and during this process the material overhead is eroded so that it can be exposed at surface. The metamorphic rock is then eroded to make more sediments, which are deposited and then buried to make sedimentary rock. This would likely take at least 60 million years.
## Exercise 3.2 Making magma viscous
Responses will vary.
## Exercise 3.3 Rock types based on magma composition
Rock Sample SiO2 Al2O3 FeO CaO MgO Na2O K2O What type of magma is it?
Rock 1 55% 17% 5% 6% 3% 4% 3% intermediate (although the SiO2 level is borderline, there is too little FeO, MgO and CaO to be mafic)
Rock 2 74% 14% 3% 3% 0.5% 5% 4% felsic
Rock 3 47% 14% 8% 10% 8% 1% 2% mafic
Rock 4 65% 14% 4% 5% 4% 3% 3% intermediate (although the SiO2 level is borderline, there is too much MgO and CaO to be felsic)
## Exercise 3.4 Porphyritic minerals
1. only olivine phenocrysts
2. pyroxene and amphibole phenocrysts, along with plagioclase with a composition that is about half-way between the Ca-rich and the Na-rich end-members.
## Exercise 3.5 Mineral proportions in igneous rocks
1. Roughly 25% K-feldspar, 30% quartz, 35% albitic plagioclase and 10 biotite/amphibole,
2. Roughly 65% plagioclase and 35% biotite/amphibole (most likely amphibole),
3. Roughly 45% anorthitic plagioclase, 25% amphibole and 35% pyroxene
4. Roughly 50% pyroxene and 50% olivine.
## Exercise 3.6 Proportions of Ferromagnesian Silicates
The approximate proportions are: 10%, 50%, 30% and 2%, and the corresponding rock names are granite, gabbro (although it’s right on the boundary between gabbro and diorite), diorite and granite.
## Exercise 3.7 Pluton Problems
1. a stock
2. a dyke (it cuts across bedding and the granite)
3. a sill (it is parallel to bedding)
4. a dyke
5. a sill
# Chapter 4
## Exercise 4.1 How thick is the oceanic crust?
The magma available to create oceanic crust at this setting is approximately 10% of the volume of the 60 kilometres thick part of the mantle from which it is derived, so the oceanic crust should be about 6 kilometres thick.
## Exercise 4.2 Under pressure
No answer possible.
## Exercise 4.3 Volcanoes and subduction
The volcanoes are between 200 and 300 kilometres from the subduction boundary, about 250 kilometres on average. If the subducting crust is descending at 40 kilometres per 100 kilometres inland, the depth to the Juan de Plate beneath these volcanoes is between 80 and 120 kilometres , or 100 kilometres on average.
## Exercise 4.4 Kilauea’s June 27th lava flow
1. The flow front advanced at a rate of about 160 metres per day or just under 7 metres per hour between June 27th and October 29th 2014. That doesn’t mean that the lava only flowed at rates of a few metres per hour over that time. It likely flowed much faster (probably 10s to 100s of metres per hour), but it advanced in fits and starts, and the advancing front changed locations many times. At other times the flow spread out across the area.
2. Between January 2015 and January 2016 the flow did not extend any further northeast towards Pahoa. Instead it spread out across the plain to the north of Pu’ u’ o’ o.
## Exercise 4.5 Volcanic hazards in Squamish
Hazard Risk
1. Tephra emission Yes. However, much of the tephra from a large eruption would extend up into the atmosphere, and would not affect Squamish.
2. Gas emission Yes. There could be dangerous amounts of sulphurous or acidic gases flowing down the mountainside into Squamish.
3. Pyroclastic density current Yes. A pyroclastic density current that flows down the western or southwestern sides of Garibaldi could easily reach Squamish.
4. Pyroclastic fall Yes. In the later stages of a large eruption some tephra (or pyroclastic fragments) could rain down on Squamish
5. Lahar Yes. Squamish is definitely at risk from a lahar on the western side of the mountain. The risk would be increased if the eruption takes place in winter or spring when the amount of snow is at a maximum.
6. Sector collapse Yes, this is possible. The western side of Mt. Garibaldi has already collapsed several times since the last glaciation.
7. Lava flow Yes. Squamish is at risk from lava that flows on the southern and western sides of the mountain. There is a Pleistocene-aged lava flow clearly evident in the photograph. It flowed down the southern flank, and then turned west towards where Squamish is situated today.
## Exercise 4.6 Volcano alert!
The most important tools for monitoring volcanoes are seismometers, and while there is a good network of seismometers in southwestern BC, there are not enough in close proximity to Mount Garibaldi to be able to accurately define the locations and depths of earthquakes around the volcano. So the first project would be to establish about 5 additional seismic stations in the Squamish region. They don’t have to be right on the mountain, but can be placed near to existing roads and highways in the area. They need to be secured to bedrock. Every effort should be made to have them located on all sides of the mountain. The second project would be to establish some means of measuring deformation of the mountain itself. This could be done with tiltmeters or GPS stations, but GPS would be better. The GPS receivers have to be placed on the flanks of the mountain, and they also have to be installed right on bedrock. That could be a real challenge in winter or spring, when there is lots of snow. While this work is going on, we should charter a helicopter to fly around the mountain to see if there is any sign of eruptive activity or melting snow, and to look for convenient places to install GPS stations. We may want to land in a few different places.
There isn’t a lot that we can say to the public at this stage, except that this sudden increase in seismic activity could mean that Garibaldi is getting ready to erupt, that the Geological Survey and all emergency measures organizations are working together on it, and that residents of the Squamish area, and anyone using highway 99, should keep listening to local radio stations for further updates. We could also establish a system to send out alerts via text message.
## Exercise 4.7 Volcanoes down under
We would expect to see composite volcanoes on the North Island, some 200 to 300 kilometres inland (northwest) from the Kermadec Trench, and within the ocean along the same trend to the northeast of New Zeland. There is also the potential for composite volcanism to the south of the South Island, east of the Macquarrie fault zone, although there appears to be some doubt about whether subduction is actually taking place in this region.
# Chapter 5
## Exercise 5.2 Chemical weathering
Chemical change Process
1. Pyrite to hematite oxidation
2. Calcite to calcium and bicarbonate ions dissolution
3. Feldspar to clay hydrolysis
4. Olivine to serpentine hydrolysis
5. Pyroxene to iron oxide oxidation
## Exercise 5.3 Describing the weathering origins of sands
Sand description Possible processes
Fragments of coral etc. from a shallow water area near to a reef in Belize Reefs are constantly being eroded by ocean waves, and the fragments are washed inshore by currents and then further eroded by wave action.
Angular quartz and rock fragments from a glacial stream deposit near Osoyoos Quartz-bearing rocks have been eroded and transported by a glacier. The fragments may have been moved a short distance by a stream, but not enough to produce rounding.
Rounded grains of olivine and volcanic glass from a beach in Hawaii The olivine and glass grains are eroded by waves from volcanic rock and then thoroughly rounded by waves on the beach
## Exercise 5.4 The soils of Canada
Soil type Distribution Explanation
1. Chernozem Southern prairies These are dry-climate soils developed on grasslands
2. Luvisol Northern prairies and BC interior Soils developed on sedimentary rocks in cool moist climates
3. Podsol Mountainous parts of BC and large parts of northern Ontario and Quebec Areas with coniferous forests and moderate climates
4. Brunisol Boreal forest regions Cold forested regions with discontinuous permafrost
5. Organic Hudson Bay and James Bay lowlands Wetland areas with widespread swamps
# Chapter 6
## Exercise 6.1 Describe the sediment on a beach
Responses will vary.
## Exercise 6.2 Classifying sandstones
Description Rock name
Angular grains, 85% quartz, 15% feldspar, less than 5% silt and clay Arkosic arenite
Rounded grains, 99% quartz, less than 2% silt and clay Quartz arenite
Angular grains, 70% quartz, 20% lithic and 10% feldspar, roughly 20% silt and clay Lithic wacke
## Exercise 6.3 Making evaporite
Responses will vary.
## Exercise 6.4 Interpretation of past environments
Description Source rock Weathering Transportation Dep. environment
1. Cross-bedded quartz sandstone, rounded grains probably sandstone strong chemical weathering wind desert
2. Feldspathic sandstone and mudstone with volcanic fragments and repetitive graded bedding granite and volcanic rock weak chemical weathering short transport in a river sub-marine fan
3. Conglomerate with well- rounded pebbles and cobbles, imbricated granite and volcanic rock difficult to tell high-energy river moderate energy river
4. Limestone breccia with orange-red matrix limestone mechanical only rock fall talus slope, oxidizing environment
# Chapter 7
## Exercise 7.1 How long did it take?
It might have taken in the order of 20 to 25 million years for these garnets to form, but even more time is needed than that to produce the rock because we have to account for the sedimentary process and then burial and lithification and then deeper burial to reach metamorphic environment – several tens of millions more years.
## Exercise 7.2 Naming metamorphic rocks
Rock Description Name
1. A rock with visible minerals of mica and with small crystals of andalusite. The mica crystals are consistently parallel to one another. Schist or (preferably) Mica-andalusite schist
2. A very hard rock with a granular appearance and a glassy lustre. There is no evidence of foliation. Probably quartzite
3. A fine-grained rock that splits into wavy sheets. The surfaces of the sheets have a sheen to them. Phyllite
4. A rock that is dominated by aligned crystals of amphibole. Amphibolite
## Exercise 7.3 Metamorphic rocks in areas with higher geothermal gradients
Metamorphic Rock Type Depth (km)
1. Slate 2 to 5
2. Phyllite 5 to 8
3. Schist 8 to 12
4. Gneiss 12 to 17
5. Migmatite 17 to 25
# Chapter 8
## Exercise 8.2 Dating rocks using index fossils
The age of the rock is probably between 92.6 and 92.7 Ma. If M. subhercynius was not present, the age range would be between 92.6 and 92.9 Ma
## Exercise 8.3 Isotopic dating
With a ratio of 0.91 the age is 175 Ma (red dotted line).
## Exercise 8.4 Magnetic dating
The possible age ranges are 3.05 to 3.12 Ma and 1.78 to 2.00 Ma
## Exercise 8.5 What happened on your birthday?
Answers will vary.
# Chapter 9
## Exercise 9.1 How soon will seismic waves get here?
Times shown for velocity of 5 kilometres per second (km/s).
1. Nanaimo (120 kilometres), 24 seconds.
2. Surrey (200 kilometres), 40 seconds.
3. Kamloops (390 kilometres), 78 seconds.
## Exercise 9.3 What does your magnetic dip meter tell you?
1. Up at a shallow angle: Southern hemisphere, near the equator.
2. Parallel to the ground: Equator.
3. Down at a steep angle: Northern hemisphere, near the pole.
4. Straight down: North pole.
## Exercise 9.4 Rock density and isostasy
Rock Type Volumes of individual minerals in 1000 cm3 Grams of individual minerals in 1000 cm3 Total Weight (grams) Density (grams per cubic centimetre, g/cm3)
Continental Crust (Granite) Quartz – 180 cm3
Feldspar – 760 cm3
Amphibole – 70 cm3
Quartz – 477 g
Feldspar – 1999 g
Amphibole – 277 g
2703 g 2.70
Oceanic Crust (Basalt) Feldspar – 450 cm3
Amphibole – 50 cm3
Pyroxene – 500 cm3
Feldspar – 1184 g
Amphibole – 164 g
Pyroxene – 1700 g
3048 g 3.05
Mantle (Peridotite) Pyroxene – 450 cm3
Olivine – 550 cm3
Pyroxene – 1530 g
Olivine – 1815 g
3345 g 3.35
# Chapter 10
## Exercise 10.3 Paper transform fault model
No answer possible.
## Exercise 10.4 A different type of transform fault
The Juan de Fuca Plate is moving faster than the Explorer Plate, which means that the Juan de Fuca Plate is sliding past the Explorer Plate. There is side-by-side relative motion on this plate boundary, and that makes it a transform fault.
# Chapter 11
## Exercise 11.1 Earthquakes in British Columbia
1. Most of the earthquakes between the Juan de Fuca (JDF) and Explorer Plates are related to transform motion along that plate boundary,
2. The string of small earthquakes adjacent to Haida Gwaii are likely aftershocks of the 2012 M7.7 earthquake in that area.
3. Most of the earthquakes around Vancouver Island (V.I.) are related to deformation of the North America Plate continental crust by compression along the subduction zone.
4. Earthquakes that are probably caused by fracking are enclosed within a red circle on the map.
## Exercise 11.2 Moment magnitude estimates from earthquake Parameters
Length (km) Width (km) Displacement (m) Comments MW?
60 15 4 The 1946 Vancouver Island earthquake 7.3
0.4 0.2 .5 The small Vancouver Island earthquake shown in Figure 11.13 4.0
20 8 4 The 2001 Nisqually earthquake described in Exercise 11.3 6.8
1,100 120 10 The 2004 Indian Ocean earthquake 9.0
30 11 4 The 2010 Haiti earthquake 7.0
The largest recorded earthquake had a magnitude of 9.5. Could there be a 10?
To have a magnitude of 10, one possible solution is 2500 kilometres long and 300 kilometres wide with 55 metres of displacement. (Other solutions are possible.) These are unreasonable numbers because subduction zones don’t tend to fail over that length (typically not much more than 1200 kilometres), rupture zones cannot be that wide because that takes us into the asthenosphere, and displacements are never likely to be that great.
## Exercise 11.3 Estimating intensity from personal observations
Building Type Floor Shaking Felt Lasted (seconds) Description of Motion Intensity?
House 1 no 10 Heard a large rumble lasting not even 10 s, mirror swayed 2
House 2 moderate 60 Candles, pictures & CDs on bookshelf moved, towels fell off racks 4
House 1 no Pots hanging over stove moved and crashed together 3
House 1 weak Rolling feeling with a sudden stop, picture fell off mantle, chair moved 4
Apartment 1 weak 10 Sounded like a big truck then everything shook for a short period 3
House 1 moderate 20-30 Teacups rattled but didn’t fall off 3
Institution 2 moderate 15 Creaking sounds, swaying movement of shelving 3
House 1 moderate 15-30 Bed banging against the wall with me in it, dog barking aggressively 4
## Exercise 11.4 Creating liquefaction and discovering the harmonic frequency
No answer possible.
## Exercise 11.5 Is your local school on the seismic upgrade list?
Answers will vary.
## Exercise 12.1 Folding style
In order to help with the interpretation, one of the beds has been traced (in yellow) on the diagram below, and two of the fold axes have been shown (in pink). These folds are symmetrical, and although they are tight they are not isoclinal. They are overturned.
## Exercise 12.2 Types of faults
Top left: a normal fault, implying extension Bottom left: a series of normal faults, extension Top right: A reverse fault, compression Bottom right: a right lateral fault (implies that there is shearing, but it is not possible to say if there is extension or compression)
## Exercise 12.3 Putting strike and dip on a map here!
See map below for strike and dip symbols. Relative ages, from youngest to oldest:
• dyke (youngest)
• fault
• layer g (although this layer isn’t intersected by the fault or the dyke so it is not possible to know that it is older based on the information available)
• layer f
• layer e
• layer d
• layer c
• layer b
• layer a (oldest)
# Chapter 13
## Exercise 13.1 How long does water stay in the atmosphere?
The volume of the oceans is 1,338,000,000 km3 and the flux rate is approximately the same (1,580 km3/day).
What is the average residence time of a water molecule in the ocean?
1,338,000,000/1,580 = 846,835 days average residence time for water in the ocean (or 2320 years)
## Exercise 13.2 The effect of a dam on base level
How does the formation of a reservoir affect the stream where it enters the reservoir, and what happens to the sediment it was carrying?
The velocity of the streams slows to zero and most of the sediment is deposited quickly.
The water leaving the dam has no sediment in it. How does this affect the stream below the dam?
With nothing to deposit, the water below the dam can only erode, so there will be enhanced erosion below the dam.
## Exercise 13.3 Understanding the Hjulström-Sundborg Diagram
1. A fine sand grain (0.1 millimetres) is resting on the bottom of a stream bed.
1. What stream velocity will it take to get that sand grain into suspension? Roughly 20 centimetres per second.
2. Once the particle is in suspension, the velocity starts to drop. At what velocity will it finally come back to rest on the stream bed? Roughly 1 centimetres per second.
2. A stream is flowing at 10 centimetres per second (which means it takes 10 seconds to go 1 metre, and that’s pretty slow).
1. What size of particles can be eroded at 10 centimetres per second? No particles, of any size, will be eroded at 10 centimetres per second, although particles smaller than 1 millimetre that are already in suspension will stay in suspension.
2. What is the largest particle that, once already in suspension, will remain in suspension at 10 centimetres per second? A 1 millimetre diameter particle should remain in suspension at 10 centimetres per second.
## Exercise 13.4 Determining stream gradients
The length of the creek between 1,600 metres and 1,300 metres elevation is 2.4 kilometres, so the gradient is 300 divided by 2.4 = 125 metres per kilometre.
1. Use the scale bar to estimate the distance between 1,300 metres and 600 metres and then calculate that gradient. 5.2 kilometres, with a gradient of 700 divided by 5.2 = 134 metres per kilometre.
2. Estimate the gradient between 600 metres and 400 metres. 3.6 kilometres, with a gradient of 200 divided by 3.6 = 56 metres per kilometre.
3. Estimate the gradient between 400 metres on Priest Creek and the point where Mission Creek enters Okanagan Lake. 4 kilometres, with a gradient of 60 divided by 4.0 = 15 metres per kilometre.
## Exercise 13.5 Flood probability on the Bow River
1. Calculate the recurrence interval for the second largest flood (1932, 1,520 m3/s). Ri = 96/2 = 48 years
2. What is the probability that a flood of 1,520 m3/s will happen next year? 1/48 = 0.02 or 2%
3. Examine the 100-year trend for floods on the Bow River. If you ignore the major floods (the labelled ones), what is the general trend of peak discharges over that time? In general the peak discharges are getting lower (from an average of around 400 m3/s in 1915 to an average of about 300 m3/s in 2015)
# Chapter 14
## Exercise 14.1 How long will it take?
$i=\dfrac{37\text{ m}-21\text{ m}}{80\text{ m}}=0.2, K=0.0002 \text{ m/s},$ and $n=0.25,$ so $V=\dfrac{0.0002\text{ m/s}\times 0.2}{0.25}=0.00016\text{ m/s}.$
At that rate, it will take 500,000 seconds for the groundwater to flow from the gas station to the stream. That converts to 138 hours, or about 6 days.
## Exercise 14.2 Cone of depression
The cone of depression increases the gradient of the water table in the area around the well. That should increase the rate at which water flows towards the well.
## Exercise 14.3 What is your water table doing?
The water-level for a random observation well in BC is shown above. The water table is slowly rising at this location. Since 2004 the lowest water level has risen from just above 4 m below surface to around 3.6 m above surface and the highest level has risen from around 0.3 m below surface to nearly at surface (0 m). Prior to 2004, where the points are not joined with lines, the trend appears to be similar.
## Exercise 14.4 What goes on at your landfill?
Responses will vary.
## Exercise 14.5 Finding a leaking UST in your community
Responses will vary.
## Exercise 14.6 Manipulating a contaminant plume
What could you do at wells A and C to prevent this? Explain and use the diagram below to illustrate the expected changes to the water table and the movement of the plume.
Possible Answer: Injection into well A will cause water table to rise there (like the reverse of a cone of depression), thus reversing flow direction to the right of well A and moving the plume towards Well B. Extraction from Wells B and C will cause cones of depression and help to reverse the flow and pull the plume back from the stream. Both wells B and C may receive contaminants and so the water from both may need treatment.
# Chapter 15
## Exercise 15.1 Sand and water
Responses will vary.
## Exercise 15.3 How much does a house weigh and can it contribute to a slope failure?
A typical 150 m2 (approximately 1,600 ft2) wood-frame house with a basement and a concrete foundation weighs about 145 t (metric tonnes). But most houses are built on foundations that are excavated into the ground. This involves digging a hole and taking some material away, so we need to subtract what that excavated material weighs. Assuming our 150 m2 house required an excavation that was 15 m by 11 m by 1 m deep, that’s 165 m3 of “dirt,” which typically has a density of about 1.6 t per m3.
165 m3 of excavated soil × 1.6 t/m3 = 264 t – thus the excavated material weighs about 1.8 times as much as the house. In this case weight has been removed from the slope by building the house.
# Chapter 16
## Exercise 16.1 Pleistocene glacials and interglacials
Describe the nature of temperature change that followed each of these glacial periods.
In each case the temperature drops slowly building to a peak of glaciation, and then each of the glacial periods is followed by a very rapid increase in temperature.
The current interglacial (Holocene) is marked with an H. Point out the previous five interglacial periods.
The previous 5 interglacials are labelled 1 to 5 on the diagram below. Interglacial 2 had two distinct warm episodes.
## Exercise 16.2 Ice advance and retreat
The red dots show the new positions of the markers.
## Exercise 16.3 Identify glacial erosion features
1. col
2. arête
3. horn
4. cirque
5. truncated spur (other arêtes are labelled in the image)
# Chapter 17
## Exercise 17.1 Wave height versus length
This table shows the typical amplitudes and wavelengths of waves generated under different wind conditions. The steepness of a wave can be determined from these numbers and is related to the ratio: amplitude/wavelength.
1. Calculate these ratios for the waves shown.
2. How would these ratios change with increasing distance from the wind that produced the waves?
Amplitude (metres) Wavelength (metres) Ratio (amplitude/wavelength)
0.27 8.5 0.03
1.5 33.8 0.04
4.1 76.5 0.05
8.5 136 0.06
14.8 212 0.07
Within increasing distance from the source the wave heights would gradually decrease and so the ratios would decrease.
## Exercise 17.3 Beach forms
Barrier islands could from if this was a low-relief coast with an abundant supply of sediment from large rivers.
## Exercise 17.4 A Holocene uplifted shore
The melting of glacial ice around the world at the end of the last glaciation (between 14 and 8 ka – see Figure 17.25) led to relatively rapid sea-level rise (by a total of approximately 125 m) which resulted in this area being submerged. That was a eustatic process. In response to the loss of ice in this region of coastal British Columbia there was a slower isostatic rebound of the crust, which is why this area is now back up above sea level.
# Chapter 18
## Exercise 18.1 Visualizing sea-floor topography
1. see map, below
2. This is the area between the southern tip of South America (Cape Horn) and the Antarctic Peninsula. The body of water between the two is the Drake Passage.
## Exercise 18.2 The age of subducting crust
1. The oldest is in the southeast and is greater than 8 Ma (see map below).
2. The youngest is in the north and is close to 0 Ma.
## Exercise 18.3 What type of sediment
1. siliceous ooze or clay
2. carbonate ooze
3. siliceous ooze or clay
4. coarse terrigenous or carbonate ooze
## Exercise 18.4 Salt chuck
No answer possible.
## Exercise 18.5 Understanding the Coriolis effect
No answer possible.
# Chapter 19
## Exercise 19.1 Climate Change at the K-Pg Boundary
The short-term climate impact was significant cooling because the dust (and sulphate aerosols) would have blocked incoming sunlight. This effect may have lasted for several years, but its intensity would have decreased over time.
The longer-term impact would have been warming caused by the greenhouse effect of the carbon dioxide.
## Exercise 19.2 Albedo Implications of Forest Harvesting
Clear-cutting (or any logging activity) leads to a net increase in albedo, so the albedo-only impact is cooling.
## Exercise 19.3 What Does Radiative Forcing Tell Us?
Using the ΔT = ΔF * 0.8 equation the expected temperatures for 2011, 1980 and 1950 compared with the estimated 13.4 C in 1750 should be:
2011 vs 1750 ΔT = 0.8 * 2.29 = 1.8°C (13.4 + 1.8 = 15.2)
1980 vs 1750 ΔT = 0.8 * 1.25 = 1.0°C (13.4 + 1.0 = 14.4)
1950 vs 1750 ΔT = 0.8 * 0.57 = 0.5°C (13.4 + 0.5 = 13.9)
Based on this reasoning the estimated temperature for 1950 is13.9˚ C (which is close to the actual of 14.0 ˚ C), while that for 1980 is 14.4˚ C, which is well above the actual of 14.2˚ C. It’s also clear that we didn’t reach 15.2˚ C by 2011, because even in the hottest year so far (2015) the global average temperature was only 14.8˚ C.
So while the ΔT = ΔF * 0.8 equation is useful, it appears to overestimate the temperature, probably because it takes some time (years to decades) for the climate to catch up to the forcing.
## Exercise 19.4 Rainfall and ENSO
Describe the relationship between ENSO and precipitation in B.C.’s southern interior.
As shown on the diagram below, there are some examples where a strong ENSO signal corresponds with very strong precipitation in the interior (and on the coast as well). The two strongest El Niños (1983 and 1998) shown correspond with the highest recorded precipitation levels in Penticton. Some other strong El Niños (1958 and 1973) are associated with strong precipitation within 6 months of the ENSO peak, but others show a negative correlation between ENSO and rainfall (marked with “?”).
## Exercise 19.5 How Can You Reduce Your Impact on the Climate?
Responses will vary.
# Chapter 20
## Exercise 20.1 Where does it come from?
Responses will vary.
## Exercise 20.2 The importance of heat and heat engines
Deposit Type Is Heat a Factor? If So, What Is the Role of the Heat?
Magmatic Yes Heat is necessary for melting of the rock to produce magma
Volcanogenic massive sulphide Yes Heat is necessary for melting of the rock to produce magma
Porphyry Yes Heat contained within the porphyritic intrusion drives the convection system
Banded iron formation No Iron is deposited from cold ocean water
Unconformity-type uranium Probably Uranium solubility is enhanced at higher water temperatures
## Exercise 20.3 Sources of important lighter metals
Element Silicon Calcium Sodium Potassium Magnesium
Source(s) quartz sand lime-stone halite (NaCl) sylvite (KCl) dolomite ((Ca,Mg)CO3), magnesite (MgCO3), salt lakes and the ocean
# Chapter 21
## Exercise 21.2 Purcell Rocks Down Under?
The Mesoproterozoic quartzite phyllite schist of Tasmania may correlate with the Purcell rocks of Canada. The main difference is that while the Tasmanian rocks are metamorphosed, the Purcell rocks are generally unmetamorphosed.
## Exercise 21.3 What Is Vancouver Island Made Of?
1. Less than 10% of Vancouver Island is Paleozoic (the Devonian volcanic rocks – Dv).
2. The most common rock type is the Triassic Karmutsen Volcanic rock (basalt – Tv). The most common rocks by age are the Mesozoic rocks (Jurassic volcanic, Jurassic granite and Triassic volcanic).
## Exercise 21.4 Dinosaur country?
This Cretaceous Dinosaur Park Formation sandstone is clearly cross-bedded implying that it was deposited in a stream environment.
## Exercise 21.5 The volume of the Paskapoo Formation
1. The 60,000 km2 area of source rock would have to have been eroded to a depth of 750 m to create 45,000 km3 of sediment
2. 500 m is 500,000 mm so the rate is 500,000 mm/ 4,000,000 years = 0.125 mm/year
# Chapter 22
## Exercise 22.1 How do we know what other planets are like inside?
Table 22.2 Find the fraction of volume that is core
Description Earth Mars Venus Mercury
Planet density (uncompressed) in g/cm3 4.05 3.74 4.00 5.30
Percent core 16.8% 10.3% 15.8% 43.2%
Table 22.3 Find the volume of the core for each planet
Description Earth Mars Venus Mercury
Unsqueezed planet volume – km3 1.47 x 1012 1.72 x 1011 1.22 x 1012 6.23 x 1010
Core volume – km3 2.48 x 1011 1.77 x 1010 1.92 x 1011 2.69 x 1010
Table 22.4 Find the percent of each planet’s radius that is core
Description Earth Mars Venus Mercury
Unsqueezed core radius in km 3900 1617 3581 1858
Unsqueezed planet radius in km 7059 3447 6623 2458
Percent of radius that is core (see diagram below) 55% 47% 54% 76%
## Exercise 22.2 How do we know the sizes of exoplanets?
Table 22.5 Calculate the radius of star Kepler-452
Description Sun Kepler-452 Ratio
Temperature (degrees Kelvin) 5778 5757 1.0036
Luminosity (x 1026 Watts) 3.846 4.615 1.20
Radius (km) 696,300 768,317
* The temperatures of the sun and Kepler-452 are very similar, but the small difference is important. Keep 4 decimal places.
Table 22.6 Calculate the radius of planet Kepler-452b
Decrease in brightness* Earth radius (km) Kepler-452b radius rplanet (km) Kepler-452b radius/ Earth radius
197 x 10-6 6378 10,784 1.7
* Because we know this is a decrease, you don’t need to keep the negative sign.
Answers for Chapter 22 were provided by Karla Panchuk.
## License
Physical Geology - 2nd Edition by Steven Earle is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.
| 2020-08-03T21:09:36 |
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https://www.bnl.gov/physics/events/past.php
|
# Physics Events
1. OCT
19
Thursday
Environmental & Climate Sciences Department Seminar
"Desert Dust, Wildfire Smoke, Volcanic Ash, Urban and Industrial Pollution – Grasping the Role Particles Play in Global Climate and Regional Air Quality"
Presented by Ralph Kahn, NASA Goddard Space Flight Center
11 am, Conference Room Bldg 815E
Thursday, October 19, 2017, 11:00 am
Hosted by: 'Steve Schwartz'
Airborne particles are ubiquitous components of our atmosphere, originating from a variety of natural and anthropogenic sources, exhibiting a wide range of physical properties, and contributing in multiple ways to regional air quality as well as regional-to-global-scale climate. Most remain in the atmosphere for a week or less, but can traverse oceans or continents in that time, carrying nutrients or disease vectors in some cases. Bright aerosols reflect sunlight, and can cool the surface; light-absorbing particles can heat the atmosphere, suppressing cloud formation or mediating larger-scale circulations. In most cases, particles are required to collect water vapor as the initial step in cloud formation, so their presence (or absence) and their hygroscopic or hydrophilic properties can affect cloud occurrence, structure, and ability to precipitate. Grasping the scope and nature of aerosol environmental impacts requires understanding microphysical-to-global scale processes, operating on timescales from minutes to days or longer. Satellites are the primary source of observations on kilometer-to-global scales. Spacecraft observations are complemented by suborbital platforms: aircraft in situ measurements and surface-based instrument networks that operate on smaller spatial scales, some on shorter timescales. Numerical models play a third key role in this work — providing a synthesis of current physical understanding with the aggregate of measurements, and allowing for some predictive capability. This presentation will focus on what we can say about aerosol amount and type from space. Constraining particle "type" is at present the leading challenge for satellite aerosol remote sensing. We will review recent advances and future prospects, including the strengths and limitations of available approaches, and current work toward better integrating measurements with models to create a clearer picture of aerosol environmental impacts, globally.
2. OCT
19
Thursday
RIKEN Lunch Seminar
"Lattice QCD and Neutrino Physics"
Presented by Aaron Meyer, HET Group
12:30 pm, Building 510, Room 2-160
Thursday, October 19, 2017, 12:30 pm
Hosted by: 'Enrico Rinaldi'
The nucleon axial form factor is a dominant contribution to systematic uncertainties in neutrino oscillation studies. The most commonly used model parametrization of the axial form factor has uncontrolled and underestimated systematic errors. First-principles computations from lattice QCD have the potential to control theory errors by disentangling the effects of nuclear corrections from the nucleon amplitudes. In this talk, I discuss fits to the axial form factor with deuterium bubble chamber data using the model-independent $z$ expansion parameterization. I then present preliminary results for a blinded lattice QCD calculation of the nucleon axial charge $g_A$ with physical light quark masses. This calculation is being done with the Highly Improved Staggered Quark (HISQ) action and 2+1+1 flavors of sea quarks.
3. OCT
19
Thursday
Particle Physics Seminar
"Study of the Higgs properties in the H->ZZ*->4l channel with the ATLAS detector"
Presented by Gaetano Barone, Brandeis University
3 pm, Small Seminar Room, Bldg. 510
Thursday, October 19, 2017, 3:00 pm
Hosted by: 'Alessandro Tricoli'
Recent measurements of the Higgs boson properties in the four lepton channel for 36.1 fb-1 of proton—proton collisions at 13 TeV using the ATLAS detector will be presented. The measurements include the Higgs boson mass as well as inclusive, fiducial and differential cross sections and, constraints on Higgs boson production couplings. The results are interpreted within the Standard Model and various extensions.
4. OCT
20
Friday
Nuclear Theory/RIKEN Seminar
"Quantization of three-body scattering amplitude in isobar formulation"
Presented by Maxim Mai, George Washington University
2 pm, Small Seminar Room, Bldg. 510
Friday, October 20, 2017, 2:00 pm
Hosted by: ''Chun Shen''
In the so-called isobar parametrization the three-particle states are populated via an interacting two-particle system (resonant or non-resonant), and a spectator. Using this parametrization, we derive the isobar-spectator interaction such that the three-body Unitarity is ensured exactly. In the first part of my talk I will show the major steps of this derivation. (arXiv:1706.06118) The second part of the talk will be dedicated to the finite-volume implementation of the framework (arXiv:1709.08222). Imaginary parts in the infinite volume, dictated by Unitarity, determine the dominant power-law finite volume effects to ensure the correct 3-body quantization condition. Furthermore, various building blocks of the 3->3 amplitude in the finite volume can become singular. However, when all contributions are summed-up, only genuine 3-body singularities remain. I will demonstrate the corresponding cancellation mechanisms explicitly for the simplified case of only one S-wave isobar.
5. OCT
20
Friday
Condensed-Matter Physics & Materials Science Seminar
"Pressure-driven collapse of Jeff=1/2 electronic state in a honeycomb iridate"
Presented by Young-June Kim, University of Toronto, Canada
3 pm, ISB Bldg. 734 Conf. Rm. 201 (upstairs)
Friday, October 20, 2017, 3:00 pm
Hosted by: '''Igor Zaliznyak'''
Orbital and spin degrees of freedom in heavy transition metal compounds can be locked into each other due to strong spin-orbit coupling. The magnetism in this case is described by an effective total angular momentum jeff=1/2 rather than usual spin angular momentum. Furthermore, these jeff=1/2 moments residing on a honeycomb lattice can be coupled through bond-dependent Kitaev interactions. Magnetic properties of some honeycomb lattice iridates, such as Na2IrO3 and Li2IrO3 have been extensively investigated to examine whether Kitaev quantum spin liquid is realized in these compounds. However, the applicability of the jeff=1/2 local moment model in real materials have not been critically scrutinized experimentally. A combination of x-ray absorption spectroscopy, x-ray diffraction, and resonant inelastic x-ray scattering experiments on a honeycomb lattice Li2IrO3 reveals that the jeff=1/2 picture breaks down under high pressure, and electrons take on more itinerant character under this condition.
6. OCT
25
Wednesday
Condensed-Matter Physics & Materials Science Seminar
"Theory and Computation Guided Discovery of New Thermoelectric Materials"
Presented by Vladan Stevanovic, Colorado School of Mines & National Renewable Energy Laboratory
1:30 pm, ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Wednesday, October 25, 2017, 1:30 pm
Hosted by: '''Cedomir Petrovic'''
Progress in the widespread adoption of all solid heat-to-electricity technologies has largely been hindered by the absence of suitable thermoelectric materials. In pursuit for new thermoelectrics recent advances in large-scale deployment of first principles calculations could be useful in identifying new promising material systems. However, the need to predict electron and phonon transport properties with sufficient accuracy renders direct assessment of the thermoelectric figure of merit (zT) for large numbers of systems unfeasible. This is true even in the case of relatively simple semiconductor materials, which could be described by the computationally inexpensive single particle theories such as density functional theory (DFT). While the state-of-the-art DFT based approaches to charge carrier and heat transport of semiconductors can deliver desired accuracy, they are currently limited to relatively simple chemistries and/or case-by-case studies. In this talk I will discuss integrated theory-computation-experiment efforts in developing a robust set of material descriptors that: (1) are rooted in the Boltzmann transport theory, but do not rely on classic and largely inapplicable constant relaxation time or constant mean free path approximations, (2) are computationally tractable allowing material searches across large chemical spaces, and (3) are sufficiently accurate to provide reliable predictions. Our approach is demonstrated to correctly identify known thermoelectric materials1 and reliably suggest new and promising candidate semiconductors.2 At the end, I will review successes and failures in our quest for new thermoelectrics, and discuss dopability of semiconductors as the critical outstanding challenge in achieving high zT materials. 1. Yan, P. Gorai, B. Ortiz, S. Miller, S. A. Barnett, T. Mason, V. Stevanovic, and E. S. Toberer, "Material descriptors for thermoelectric performance", Energy Environ. Sci. 2. P. Gorai, V. Stevanovic, and E. Tobe
7. OCT
26
Thursday
RIKEN Lunch Seminar
"Approach to equilibrium of quarkonium in quark-gluon plasma"
Presented by Xiaojun Yao, BNL
12:30 pm, Building 510, Room 2-160
Thursday, October 26, 2017, 12:30 pm
Hosted by: 'Hiromichi Nishimura'
8. OCT
26
Thursday
Particle Physics Seminar
"Observation of Coherent Elastic Neutrino-Nucleus Scattering by COHERENT"
Presented by Kate Scholberg, Duke University
3 pm, Small Seminar Room, Bldg. 510
Thursday, October 26, 2017, 3:00 pm
Hosted by: 'Xin Qian'
Coherent elastic neutrino-nucleus scattering (CEvNS) is a process in which a neutrino scatters off an entire nucleus at low momentum transfer, and for which the observable signature is a low-energy nuclear recoil. It represents a background for direct dark matter detection experiments, as well as a possible signal for astrophysical neutrinos. Furthermore, because the process is cleanly predicted in the Standard Model, a measurement is sensitive to beyond-the-Standard-Model physics, such as non-standard interactions of neutrinos. The process was first predicted in 1973. It was measured for the first time by the COHERENT collaboration using the high-quality source of pion-decay-at-rest neutrinos from the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory and a CsI[Na] scintillator detector. This talk will describe COHERENT's recent 6.7-sigma measurement of CEvNS, the status and plans of COHERENT's suite of detectors at the SNS, and future physics reach.
9. OCT
27
Friday
Particle Physics Seminar
"Search for dark matter at the CMS experiment"
Presented by Adish Vartak, University of California San Diego
10 am, Small Seminar Room, Bldg. 510
Friday, October 27, 2017, 10:00 am
Hosted by: ''Alessandro Tricoli''
There is an extensive, on-going dark matter search program at the LHC that explores several different types of possible interactions between WIMP-like dark matter and standard model particles. The dark matter searches at the LHC are complementary, and in case of certain models, significantly more sensitive than the direct and indirect dark matter searches. In this talk I will discuss several key dark matter searches being pursued by the CMS collaboration. These cover a wide variety of final states in which dark matter particles are produced in association with one or more energetic, visible objects in the detector resulting in 'MET+X' signatures. Furthermore, I will also discuss the constraints set on dark matter interactions by certain resonance searches.
10. NOV
1
Wednesday
HET/RIKEN Seminar
"TBA"
2 pm, Small Seminar Room, Bldg. 510
Wednesday, November 1, 2017, 2:00 pm
Hosted by: 'Sally Dawson'
11. NOV
2
Thursday
RIKEN Lunch Seminar
"Rotating Dirac fermion in Magnetic field in 1+2 and 1+3 dimensions"
Presented by Yizhuang Liu, Stony Brook University
12:30 pm, Building 510, Room 2-160
Thursday, November 2, 2017, 12:30 pm
Hosted by: 'Hiromichi Nishimura'
12. NOV
2
Thursday
Particle Physics Seminar
"UCNtau: A magneto-gravitational trap measurement of the free neutron lifetime"
Presented by Robert Pattie, Los Alamos National Laboratory
3 pm, Small Seminar Room, Bldg. 510
Thursday, November 2, 2017, 3:00 pm
Hosted by: ''Xin Qian''
The neutron is the simplest nuclear system that can be used to probe the structure of the weak interaction and search for physics Beyond the Standard Model. Measurements of neutron ?-decay observables are sensitive to scalar and tensor interactions in the weak force which are not present in the Standard Model. The lifetime of the neutron ?n is an important parameter for Big-Bang Nucleo-synthesis models, solar fusion models, and absolute neutrino scattering cross-sections, and can be used to test the unitarity of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. Presently, the two typical methods used to measure the neutron lifetime, cold neutron beam measurements and stored ultracold neutron (UCN) measurements, disagree by roughly 4?. This discrepancy motivates the need for new measurements with complementary systematic uncertainties to previous efforts. The UCN? experiment uses an asymmetric magneto-gravitational UCN trap with in situ counting of surviving neutrons to measure the neutron lifetime. Previous bottle experiments confined UCN in a material storage vessel creating a significant correction due to losses resulting from the material UCN interactions. The magnetic and gravitational confinement of the UCN minimizes losses due to material interactions. Additionally, UCN? uses a detection system that is lowered into the storage volume which avoids emptying the surviving UCN into an external detector. This minimizes any possible transport related systematics. This in situ detector also enables counting at various heights in the vessel, which provides information on the trapped UCN energy spectrum, quasi-bound orbits, and possible phase space evolution. I will present the physics motivation for precision neutron physics, a description of the UCN? experiment, the results of data collected during the 2016-2017 accelerator cycle which resulted in a value of τn=877.7±(0.7) stat (+0.3/−0.1) sys in agreement with previous material bottle
13. NOV
3
Friday
Condensed-Matter Physics & Materials Science Seminar
"Wandering amongst the Feynamn diagrams"
Presented by Nikolay Prokofiev, University of Massachusetts-Amherst
11 am, ISB Bldg. 734 Conf. Rm. 201 (upstairs)
Friday, November 3, 2017, 11:00 am
Hosted by: ''Igor Zaliznyak''
Feynman diagrams are the most celebrated and powerful tool of theoretical physics usually associated with the analytic approach. I will argue that diagrammatic expansions are also an ideal numerical tool with enormous and yet to be explored potential for solving interacting many-body systems by direct simulation of Feynman diagrams (bare or skeleton) for the proper self-energies and polarization operators up to high order. Though the original series based on are propagators are sign-alternating and often divergent one can determine the answer behind them by using proper series re-summation techniques and working with skeleton diagrams, i.e. by making the entire scheme self-consistent. The bottom line is that the diagrammatic Monte Carlo approach generically solves the computational complexity for interacting fermionic systems. In terms of physical applications, I will disucss results for the Hubbard model, resonant fermi gas at unitarity, and stability of Dirac liquid against strong Coulomb interaction in graphene.
14. NOV
3
Friday
Nuclear Theory/RIKEN Seminar
Presented by Gerald Miller, University of Washington
2 pm, Small Seminar Room, Bldg. 510
Friday, November 3, 2017, 2:00 pm
Hosted by: 'Chun Shen'
15. NOV
6
Monday
Condensed-Matter Physics & Materials Science Seminar
"Proximity effects in cuprate/manganite multilayers"
Presented by Christian Bernhard, University of Fribourg, Germany
1:30 pm, ISB Bldg. 734 Seminar Room 201 (upstairs)
Monday, November 6, 2017, 1:30 pm
Hosted by: '''Chris Homes'''
Recently we observed an intriguing, magnetic-filed-induced insulator-to-metal transition in YBa2Cu3O7/Pr1-xCaxMnO3 (YBCO/PCMO) multilayers [1]. In the low field regime, the response of these multilayers is highly resistive and resembles the one of granular superconductors or frustrated Josephson-networks. Notably, a coherent superconducting response can be restored with a large magnetic field. The latter also suppresses the charge/orbital order of the PCMO layers towards a ferromagnetic state. This coincidence suggests an intimate relationship between the insulator-to-superconductor transition in the YBCO layer and the suppression of the charge/orbital order in the PCMO. I will discuss the evidence, based on resonant x-ray scattering experiments, that the latter induces (or strongly enhances) a static Cu-CDW order in YBCO that is intertwined with superconductivity. [1] B.P.P. Mallett et al., Phys. Rev. B 94, 180503(R) (2016).
16. NOV
9
Thursday
Condensed-Matter Physics & Materials Science Seminar
"Quasiparticle spectra from stochastic many-body methods"
Presented by Vojtech Vlcek, University of California, Los Angeles
1:30 pm, ISB Bldg. 734 Conf. Rm. 201 (upstairs)
Thursday, November 9, 2017, 1:30 pm
Hosted by: ''Igor Zaliznyak''
TBD
17. NOV
9
Thursday
Particle Physics - SB/BNL Joint Cosmo seminar (at BNL)
"Dark Matter Searches with CCDs and the Sensei Experiment"
Presented by Dr. Javier Tiffenberg, FNAL
3 pm, Small Seminar Room, Bldg. 510
Thursday, November 9, 2017, 3:00 pm
Hosted by: ''Erin Sheldon''
18. NOV
14
Tuesday
Physics Colloquium
"TBA"
Presented by Christoph Lehner, BNL
3:30 pm, Large Seminar Room, Bldg. 510
Tuesday, November 14, 2017, 3:30 pm
Hosted by: ''Rob Pisarski''
19. NOV
16
Thursday
RIKEN Lunch Seminar
"QCD from gluon, quark, and meson correlators"
Presented by Mario Mitter, BNL
12:30 pm, Building 510, Room 2-160
Thursday, November 16, 2017, 12:30 pm
Hosted by: 'Hiromichi Nishimura'
We present non-perturbative first-principle results for quark-, gluon- and meson 1PI correlation functions of two-flavour Landau-gauge QCD in the vacuum and Yang-Mills theory at finite temperature. They are obtained by solving their Functional Renormalisation Group equations in a systematic vertex expansion, aiming at apparent convergence within a self-consistent approximation scheme. These correlation functions carry the full information about the theory and their connection to physical observables is discussed. The presented calculations represent a crucial prerequisite for quantitative first-principle studies of QCD and its phase diagram within this framework. In particular, we have computed the ghost, quark and scalar-pseudoscalar meson propagators, as well as gluon, ghost-gluon, quark-gluon, quark, quark-meson, and meson interactions and the magnetic and electric components of the gluon propagator, and the three- and four-gluon vertices. Our results stress the crucial importance of the quantitatively correct running of different vertices in the semi-perturbative regime for describing the phenomena and scales of confinement and spontaneous chiral symmetry breaking without phenomenological input. We confront our results for the correlators with lattice simulations and compare our Debye mass to hard thermal loop perturbation theory. Finally, applications to "QCD-enhanced" low-energy effective models of QCD are discussed.
20. NOV
16
Thursday
Condensed-Matter Physics & Materials Science Seminar
"TBA"
Presented by Zurab Guguchia, Columbia University
1:30 pm, ISB Bldg. 734, Conference Room 201 (upstairs)
Thursday, November 16, 2017, 1:30 pm
Hosted by: ''Emil Bozin''
TBA
21. NOV
29
Wednesday
HET/RIKEN Seminar
"TBA"
2 pm, Small Seminar Room, Bldg. 510
Wednesday, November 29, 2017, 2:00 pm
Hosted by: 'Sally Dawson'
22. DEC
6
Wednesday
HET/RIKEN Seminar
2 pm, Small Seminar Room, Bldg. 510
Wednesday, December 6, 2017, 2:00 pm
Hosted by: 'Sally Dawson'
23. DEC
13
Wednesday
HET/RIKEN Seminar
"TBA"
2 pm, Small Seminar Room, Bldg. 510
Wednesday, December 13, 2017, 2:00 pm
Hosted by: 'Sally Dawson'
1. Particle Physics Seminar
"The R&D and Mass Production of 20"MCP-PMT for Neutrino Detection"
Presented by Dr. Sen Qian, IHEP China
Monday, October 16, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
Researchers at IHEP, Beijing have conceived a new concept of MCP-PMT several years ago. The small MCP (Microchannel Plate) units replace the bulky Dynode chain in the tranditional large PMTs for better photoelectron detection. After three years R&D, a number of 8 inch prototypes were produced and their performance was carefully tested at IHEP in 2013 by using the MCP-PMT evaluation system built at IHEP. The 20 inch prototypes were followed in 2014, and its' performance were improving a lot in 2015. Compensating the PMT performances with fiducially volume convert all specifications to cost, radioactivity, dark noise, TTS, the JUNO ordered 15000 pic 20-inch MCP-PMT from the NNVT in Dec.2015. In 2016, the MCP-PMT collaboration group finished to build the mass production line in Nanjing at the end of 2016, and finished the batch test system in the same place within 100 days at the beginning of 2017. From 2017 to 2019, all the 20-inch MCP-PMT will be produced and tested one by one in NNVT for JUNO. This presentation will talk about the R&D process and mass production, batch test result of the first 2K pieces of MCP-PMT prototypes for JUNO.
2. Condensed-Matter Physics & Materials Science Seminar
"Domain walls and phase boundaries - new nanoscale functional elements in complex oxides"
Presented by Jan Seidel, UNSW Sydney
Monday, October 16, 2017, 1:30 pm
Bldg. 480, Conference Room
Hosted by: ''Myung-Geun Han''
Topological structures in functional materials, such as domain walls and skyrmions, see increased attention due to their properties that can be completely different from that of the parent bulk material [1]. I will discuss recent results on multiferroic phase boundaries, domain walls in BiFeO3 [2, 3, 4, 5, 6] using SPM, TEM and ab-initio theory, and discuss future prospects [7]. References [1] J. Seidel (ed.), Topological structures in ferroic materials: domain walls, skyrmions and vortices, ISBN: 978-3-319-25299-5, Springer, Berlin (2016) [2] P. Sharma, et al., Scientific Reports 6, 32347 (2016) [3] P. Sharma, et al., Advanced Electronic Materials 2, 1600283 (2016) [3] J. Seidel, et al., Advanced Materials 26, 4376 (2014) [4] Y. Heo, et al., Advanced Materials 26, 7568 (2014) [5] Y. Heo et al., ACS Nano, DOI: 10.1021/acsnano.6b07869 (2017) [6] P. Sharma, et al., Advanced Materials Interfaces 3, 1600033 (2016) [7] J. Seidel, Nature Nanotechnology 10, 190 (2015)
3. Nuclear Theory/RIKEN Seminar
"What can we learn from flow observables in heavy-ion collisions?"
Presented by Jacquelyn Noronha-Hostler, Rutgers University
Thursday, October 12, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Chun Shen'
The Quark Gluon Plasma (QGP), nature's first and most perfect liquid, has been successfully reproduced in heavy-ion collisions at RHIC and the LHC. The dynamics of the QGP can be well described by relativistic viscous hydrodynamics, allowing for precise comparisons to experimental data in order to extract the properties of the QGP. While a small shear viscosity is well-established, questions still remain regarding the precise initial state, the temperature dependence of viscosity, the smallest system that displays QGP-like properties, and the equation of state at large densities. In this talk, the various flow harmonic observables are analyzed to help answer these remaining questions.
4. Particle Physics Seminar
"SB/BNL Joint Cosmo Seminar (at Stony Brook)"
Presented by Chang Feng, UC Irvine
Wednesday, October 11, 2017, 1:30 pm
Stony Brook
Hosted by: '''Neelima Sehgal'''
5. Nuclear Physics Seminar
"The nature of flow fluctuations, from pp to A+A, and back again"
Presented by Mingliang Zhou, Stony Brook University
Tuesday, October 3, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Jiangyong Jia'
In recent years, there have been rapid progresses in our understanding of the event-by-event flow fluctuation, which provides direct insight into the fluctuations in the initial geometry. I will start my talk by briefly discussing the flow (collectivity) and its fluctuation in small systems pp and p+Pb, using the newly-proposed subevent cumulant method, which is able to suppress the non-flow background effectively. I will show there is significant fluctuation of elliptic flow $v_2$ in pp and non-Gaussian fluctuation of triangular flow $v_3$ in p+Pb. Moving from small to large systems, STAR collaboration recently has shown different behaviors of cumulant $c_2\{4\}$ between Au+Au and U+U in ultra-central collisions, which is believed to support the different geometry fluctuations. By presenting the newest ATLAS flow measurements in ultra-central collisions, together with detailed MC Glauber studies, I will explain why sign change of $c_2\{4\}$ is observed and its implications. In the end, I will go back to small systems and discuss the potential impact of centrality resolution on pp flow measurements.
6. Particle Physics Seminar
"Latest Results from the T2K Experiment"
Presented by Kendall Mahn, Michigan State University
Friday, September 29, 2017, 3:30 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Xin Qian''
One of the most promising investigations of beyond-the-Standard-Model physics has been the study of neutrino oscillation, that is, the conversion of neutrinos from one flavor to another as they propagate. While neutrino oscillation is studied in a wide variety of experiments, accelerator based experiments, such as T2K, use a muon neutrino or antineutrino beam as a source to look for electron (anti)neutrino appearance, muon neutrino disappearance. The source also is used to make measurements of neutrino interactions and search for exotic physics. This talk will describe a recent analysis of both neutrino and antineutrino beam data from T2K. Comparisons between neutrino and antineutrino event rates provide a tantalizing window on possible CP violation in the neutrino sector. The talk will also highlight the increasingly important role of systematic uncertainty assessment for T2K and other future measurements of CP violation with accelerator beams.
7. Nuclear Theory/RIKEN Seminar
"QCD on a small circle"
Presented by Aleksey Cherman, University of Washington
Friday, September 29, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
Recent developments have shown that QCD-like theories can be engineered to remain in a confined phase when compactified on an arbitrarily small circle, where their features may be studied quantitatively in a controlled fashion. I'll explain how a non-perturbative mass gap and chiral symmetry breaking, which are both historically viewed as prototypical strong coupling effects, appear from systematic weak-coupling calculations. Then I'll describe the rich spectrum of hadronic states, including glueball, meson, and baryon resonances in the calculable small-circle context.
8. Particle Physics Seminar
"Beauty and charm decays and physics beyond the Standard Model: an experimentalist perspective"
Presented by Marina Artuso, Syracuse University
Thursday, September 28, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Alessandro Tricoli'
The Standard Model provides a comprehensive explanation for a vast array of data collected at different experiments. Nonetheless fundamental questions remain unanswered and the search for a more complete theory is still a coveted goal of particle physics. Recently, tensions with standard model predictions have been uncovered in several experimental observables in b-hadron decays at LHCb. I will discuss the data, possible implications, and the connection with other experimental programs such as study of kaon rare decays and neutrino mixing and CP violation
9. Condensed-Matter Physics & Materials Science Seminar
"Suppression of weak ferromagnetism in ultrathin iridates by interfacial engineering of octahedral rotations"
Presented by Yuefeng Nie, Nanjing University, China
Thursday, September 28, 2017, 1:30 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)
Hosted by: '''Weiguo Yin'''
Layered iridates, Srn+1IrnO3n+1, have drawn great attention since they share remarkable similarities with high-Tc cuprates, including layered crystalline structure, (pseudo) spin ½ states, antiferromagnetic (AFM) Mott insulating ground state, Fermi arcs, and V shape energy gap, etc. Nonetheless, direct evidences of superconductivity such as zero resistivity and Meissner effect are still lacking up to date. The strong spin-orbit coupling and IrO6 octahedral rotations in 5d iridates result in a canted AFM ground state with weak ferromagnetic moments in each IrO2 plane. Here, we propose to suppress the weak ferromagnetism by suppressing the octahedral rotations in iridates, which may facilitate the Cooper pairing. Using a combination of reactive molecular beam epitaxy (MBE), in situ angleresolved photoemission spectroscopy (ARPES) and first principle calculations, we investigate the evolution of octahedral rotations, electronic structure and magnetic ordering in ultra-thin SrIrO3 films grown on (001) SrTiO3 substrate. Our experimental results and theoretical calculations show that octahedral rotations and weak ferromagnetic moments are fully suppressed in 1 and 2 unit cell thick SrIrO3 films through interfacial clamping effects. If time allows, I will also present our recent work on the new understanding of RHEED oscillations in the growth of oxides and the chemically specific termination control of oxide interfaces via layerby- layer mean inner potential engineering.
10. RIKEN Lunch Seminar
"Color Memory, Large Gauge Transformations, and Soft Theorems in Yang-Mills Theory"
Presented by Monica Pate, Harvard University
Thursday, September 28, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: '''Hiromichi Nishimura'''
An infinite dimensional symmetry group which governs the infrared sectors of gauge and gravity theories has been recently discovered. This symmetry can be established both from an asymptotic symmetry analysis as well as from the corresponding Ward identities which are quantum field theoretic soft theorems. Moreover, the spontaneous breaking of these symmetries induces vacuum transitions which are detectable by charged particles through the so-called memory effect. In this seminar, I will explain the precise equivalence between asymptotic symmetries, soft theorems and memory effects in the context of tree level Yang-Mills. In particular, in this context the soft gluon theorem is Ward identity of a large gauge symmetry, whose action on the vacuum can be measured from the relative color charge of colored detectors.
11. Condensed-Matter Physics & Materials Science Seminar
"Ultrafast TEM and Time-of-Flight EELS using microwave cavities"
Presented by Jom Luiten, Eindhoven University of Technology, Netherlands
Friday, September 22, 2017, 11 am
Bldg. 480, Conference Room
Hosted by: '''Yimei Zhu'''
Ultrafast Transmission Electron Microscopy (U-TEM) has become a very important tool for the study of ultrafast phenomena at (sub-)nm length scales and (sub-)ps time scales. U-TEM is usually based on the creation of ultrashort electron pulses by femtosecond laser photoemission from a flat cathode, with the result that both the beam quality and the average current are significantly less than in state-of-the-art continuous-beam TEMs. At Eindhoven University we have developed U-TEM in which ultrashort electron pulses are produced by using a 3 GHz deflecting microwave cavity in TM110 mode to sweep a high-brightnes continuous beam across a slit [1]. We have demonstrated ultrafast beam chopping with conservation of the beam quality and the sub-eV energy spread of the FEG source of an adapted 200 keV Tecnai TEM, enabling atomic resolution with sub-ps temporal resolution at 3 GHz rep rate [2] In addition we have developed a new method for doing Time-of-Flight Electron Energy Loss Spectroscopy (ToF-EELS) based on the combined use of two TM110 deflecting cavities and two TM010 (de)compression cavities. The first 'chopping' TM110 cavity produces ultrashort electron pulses which are sent through a sample. Energy loss in the sample translates into reduction of the electron velocity and thus into a later arrival time at the detector, which is measured with a synchronized second TM110 'streak' cavity. In this way an energy resolution of 12 eV at 30 keV has been demonstrated [3]. By adding a TM010 (de)compression cavity after the sample, the longitudinal phase space can be manipulated in such a way that the energy resolution is improved to 2 eV (to be published). By adding a second TM110 cavity before the sample, full control over the longitudinal phase space can be achieved. Detailed charged particle tracking simulations show that an energy resolution of 20 meV combined with a temporal resolution of 2 ps can be achieved; or, alternatively, 2
12. Particle Physics Seminar
"Evidence for the H to bb decay with the ATLAS detector"
Presented by Giacinto Piacquadio, Stony Brook University
Thursday, September 21, 2017, 4 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Alessandro Tricoli'
Most Higgs bosons are expected to decay to a pair of b-quarks, with the Standard Model predicting a branching fraction of about 58%. Probing this decay is important to furthering our understanding of the Higgs sector, but its observation at hadron colliders is complicated by overwhelming Standard Model backgrounds. In this seminar, the search for the Higgs to bb decay, looking at the associated production of the Higgs boson with a W or Z boson, is presented, based on 36 fb-1 of 13 TeV LHC Run 2 data.
13. Condensed-Matter Physics & Materials Science Seminar
"Two new applications of geometric critical phenomena for disordered electron systems"
Presented by Matthew Foster, Rice University
Thursday, September 21, 2017, 1:30 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)
Hosted by: ''Robert Konik''
I will discuss two very recent results relating to the properties of electrons in two spatial dimensions (2D), subject to the effects of quenched disorder (impurities) and quantum interference [Anderson (de)localization]. In both cases, the key physics is tied to classical geometric critical phenomena in 2D. I will first present numerical evidence that strongly suggests the equivalence of disordered surface states of topological superconductors and geometric percolation. Percolation is known to play a role in quantum Hall systems with magnetic fields. Our unexpected result implies that percolation applies to topological superconductor surface states in the absence of time-reversal symmetry breaking. Moreover, the usual "even-odd" effect that occurs in such a system (as identified by Pruisken in the integer quantum Hall effect and by Haldane for spin chains) is found to be absent. Second, I will discuss a "toy model" for the ergodic to many-body localized phase transition in 2D, and relate it to an effective self-interacting walk. I will present analytical results of a controlled expansion which suggest that the transition can be viewed as a "dephasing catastrophe."
14. Nuclear Theory/RIKEN Seminar
"TMD gluon distributions for dijet production and their behavior at small x"
Presented by Elena Petreska, NIKHEF
Friday, September 15, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
Starting from the Color Glass Condensate (CGC) cross section for dijet production in proton-nucleus collisions we derive a transverse-momentum-dependent (TMD) factorization formula for small transverse-momentum imbalance of the jets and for finite number of colors. For the eight TMD distributions appearing in the cross section we determine their operator definitions at small-x as CGC correlators of Wilson lines and we study their JIMWLK evolution. We find that at large transverse momentum the universality of TMDs gets restored. We also discuss an extension of the approach to generalized TMDs (GTMDs) that can give an insight into the angular correlations between impact parameter and dipole size in the CGC framework.
15. Particle Physics Seminar
"SB/BNL Joint Cosmo seminar (at BNL): Mapping the Cosmos with the Dark Energy Survey"
Presented by Dr. Chihway Chang, ETH Zurich
Thursday, September 14, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: '''Erin Sheldon'''
The first year data from the Dark Energy Survey (DES Y1) provides the most powerful optical survey dataset to date. In this talk I will first give an overall summary of the cosmology results from the DES Y1 dataset combining galaxy clustering and weak gravitational lensing. Next, I will describe our work in generating and testing the wide-field weak lensing mass maps from the galaxy shape measurements and some exciting applications for the maps. I will end with thoughts on how weak lensing could also inform us on various topics of galaxy formation, which is essential for completing the story behind the Universe we see today.
16. RIKEN Lunch Seminar
"Thermal Fluctuations in Hydrodynamic Simulations of QGP"
Presented by Mayank Singh, McGill University
Thursday, September 14, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Hiromichi Nishimura''
Multi-particle correlations measured in heavy-ion collision experiments carry info on fluctuations present in the entire evolutionary history of the system. Initial states include geometric and quantum fluctuations and are important contributors. The thermal fluctuations during the course of QGP evolution is another conceptually important source of these fluctuations and should be studied in detail. We begin by treating thermal fluctuations as a linearized perturbation on hydrodynamic background. We present a full calculation of hadronic and photonic observables including these fluctuations. Recently we have included fluctuations in our simulations in a non-perturbative manner. Progress based on this approach will be discussed.
17. Physics Colloquium and Leona Woods Lecture
"Momentum-space structure of hadrons and nuclei at high energy"
Presented by Elena Petreska, NIKHEF
Tuesday, September 12, 2017, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: 'Peter Petreczky'
Transverse-momentum-dependent (TMD) distributions describe the configuration of quarks and gluons inside protons and nuclei in three-dimensional momentum space. Observables in scattering experiments can be calculated with the help of TMD factorization formulas, where the target and projectile are represented with non-perturbative TMD distributions, which are separated from the short-distance perturbative part of the collision. A complementary approach to study the momentum structure of protons and nuclei at high energy is the Color Glass Condensate which is an effective theory for the high-gluon-density region of ultra-relativistic particles. We introduce both theories and we discuss connections between them. We present phenomenological results derived from these connections.
18. NSLS-II Seminar
"On the assessment of radiation damage and high temperature effects in novel nuclear materials using the BNL accelerators and synchrotrons"
Presented by Nick Simos, Sr Scientist Emeritus, BNL
Friday, September 8, 2017, 3 pm
Large Seminar Room, Bldg. 510
Hosted by: ''Ron Pindak''
In search for new and improved materials, composites and super-alloys capable of withstanding the anticipated extreme states associated fusion reactors; high temperature fast reactors and multi-MW particle accelerators, novel reactor steels, super-alloys and composites are continuously being explored to help meet both the challenge of the higher demand environments and the intended application. Higher fluxes and fluences of irradiating species (neutrons and/or protons), extreme temperatures and aggressively corrosive environments make up the new cocktail of operating conditions of the new array of material structures. One of the challenges in characterizing the effects that high radiation fluxes of neutrons and protons induce on these novel material structures in conjunction with high temperatures is the link between lattice induced damage and phase transformation and macroscopic physical properties which ultimately determine performance in the real environment. High energy X-rays at the BNL synchrotrons have offered a path in establishing this important connection between micro-scale effects and physical properties of novel material structures exposed to high radiation fluxes. Specifically, by integrating the unique capabilities of the BNL accelerator complex that includes, in addition to the NSLS and NSLS II, the proton accelerator and Tandem as well as those of CFN, the evolution and/or damage of materials ranging from classical structures such as graphite, beryllium and steels to novel super-alloys, such as those of Invar and "Gum" metal, and new composites have been characterized both at the two length scales. The pivotal role of high energy X-rays from NSLS to NSLS II in making the connection will be presented demonstrating the enormous potential of the NSLS II in answering fundamental questions in our path towards the next generation nuclear materials. Furthermore, first glimpses of the correlation of lattice effects or damage induced by differ
19. NSLS-II Colloquium Series
"Experiments, Analyses, and Manipulations with Particle Beam"
Presented by Shyh-Huan Lee, Indiana University, IN
Thursday, September 7, 2017, 4 pm
Large Seminar Room, Bldg. 510
Hosted by: ''''''''''John Hill''''''''
Progress on particle beam physics research have provided marked improvements in beam intensity, brightness, and stability advancing frontier research in applied and fundamental science. This talk will review some beam measurements and manipulation studies being undertaken to improve beam performance in storage rings. Hopefully, these studies will be relevant to the operation and improvement of National Accelerator User Facilities.
20. Particle Physics Seminar
"Radiation damage study of a thin YAG:Ce scintillator using low-energy protons"
Presented by Dr. Vladmir Linhart, Czech Technical University in Prague
Thursday, September 7, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: '''Xin Qian'''
Radiation hardness of a 50µm thin YAG:Ce scintillator in a form of dependence of a signal efficiency on 3.1MeV proton ?uence was measured and analyzed using X-ray beam. The signal efficiency is a ratio of signals given by a CCD chip after and before radiation damage. The CCD chip was placed outside the primary beam because of its protection from damage which could be caused by radiation. Using simplified assumptions, the 3.1MeV proton fluencies were recalculated to: • 150 MeV proton fluencies with intention to estimate radiation damage of this sample under conditions at proton therapy centers during medical treatment, • 150 MeV proton doses with intention to give a chance to compare radiation hardness of the studied sample with radiation hardness of other detectors used in medical physics, • 1 MeV neutron equivalent fluencies with intention to compare radiation hardness of the studied sample with properties of position sensitive silicon and diamond detectors used in nuclear and particle physics. The following results of our research were obtained. The signal efficiency of the studied sample varies slightly (±3%) up to 3.1MeV proton ?uence of c. (4 − 8) × 1014 cm−2. This limit is equivalent to 150MeV proton ?uence of (5 − 9) × 1016 cm−2, 150MeV proton dose of (350 − 600) kGy and 1MeV neutron ?uence of (1 − 2) × 1016 cm−2. Beyond the limit, the signal efficiency goes gradually down. Fifty percent decrease in the signal efficiency is reached around 3.1MeV ?uence of (1 − 2) × 1016 cm−2 which is equivalent to 150 MeV proton ?uence of around 2 × 1018 cm−2, 150MeV proton dose of around 15 MGy and 1 MeV neutron equivalent ?uence of (4 − 8) × 1017 cm−2. In contrast with position sensitive silicon and diamond radiation detectors, the studied sample has at least two order of magnitude greater radiation resistance. Therefore, YAG:Ce sci
21. Simons Center for Geometry and Physics Public Lecture
"Mysteries of the Universe and Everyday Life"
Presented by Michelangelo Mangano; Young-Kee Kim; Joe Lykken, LHC/CERN; University of Chicago; Fermilab
Tuesday, September 5, 2017, 5:30 pm
Simons Center at Stony Brook University, Della Pie
In the past few decades we have learned a great deal about the basic laws of Physics in the infinitely small – and the infinitely large – and how the two are intimately connected. New windows have expanded our understanding, and many unexpected questions have emerged. This is an exhilarating time in history. New tools, both theoretical and observational, may lead in the next decade to major advances in our understanding of the universe. As in the past, when major discoveries are made about the fundamental laws of Nature, not only is our view of the world enriched, but also our life is transformed. A good place to explore the discoveries from the past decades is in the description of symmetry, symmetry breaking and the Higgs boson in High Energy Physics: why, how and where to…. in a nutshell. These talks will present what we know and what we seek in the fundamental laws of Nature; how we go about answering basic questions in high energy experiments, how much we have learned, and how the technical developments needed to make discoveries have changed society. They will also delineate the boundaries of our knowledge and the known unknowns in fundamental high energy physics and cosmology.
22. Particle Physics Seminar
"Wiener-SVD approach to data unfolding"
Presented by Dr. Hanyu Wei, BNL
Thursday, August 31, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
Data unfolding is a commonly used technique in the high energy physics experiments, to retrieve the distorted or transformed measurements by various detector effects. Inspired by the deconvolution technique in the digital signal processing, a new unfolding technique based on the Singular Value Decomposition (SVD) of the response matrix is developed. With the well-known Wiener filter concept, the modified SVD approach, Wiener-SVD, achieves the maximizing signal-to-noise ratio of the binned data in a transformed set of orthonormal bases where the uncertainties are bin-to-bin uncorrelated. In this talk, the mathematical principles and formulations of the newly developed Wiener-SVD unfolding will be presented. A few applications will be demonstrated. A comparison with the commonly used regularization method will also be shown. The advantages and disadvantaged of the Wiener-SVD approach will be discussed.
23. Nuclear Theory/RIKEN Seminar
"QCD corrections to high-pT hadron production in ep scattering"
Presented by Werner Vogelsang, Tuebingen University
Friday, August 25, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
We discuss various cross sections and spin observables in high-pT hadron production in lepton proton collisions, with special focus on the role of perturbative QCD corrections. We present phenomenological studies relevant for present fixed-target experiments and for a future EIC.
24. Particle Physics Seminar
"Precision tests with antimatter: A glimpse at the 1S – 2S transition in trapped antihydrogen"
Presented by Dr. William Bertsche, CERN
Thursday, August 24, 2017, 10 am
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
Optical spectroscopy with antihydrogen atoms remains one of the most promising routes towards testing CPT invariance and physics beyond the Standard Model in an effort to address the observed Baryon asymmetry in the Universe today. The ALPHA collaboration has made significant progress towards the first measurements of optical transitions in trapped antihydrogen atoms, and has recently published the first observation of the 1S – 2S transition in a fully antimatter atom. This work finds the transition consistent with CPT invariance at a level of approximately 2 x 10-10 [1]. This talk will review the details of this pioneering experiment and discuss the prospects of future spectroscopy studies and other fundamental measurements with the ALPHA experiment. [1] M. Ahmadi, et al (ALPHA Collaboration), "Observation of the 1S–2S transition in trapped antihydrogen" Nature 541, 506–510 (2017).
25. Condensed-Matter Physics & Materials Science Seminar
"Experiments on electron hydrodynamics with and without applied magnetic fields"
Presented by Andrew Mackenzie, Max-Planck-Institute, Germany
Wednesday, August 23, 2017, 1:30 pm
Bldg. 734, ISB Conf. Room 201 (upstairs)
Hosted by: '''Cedomir Petrovic'''
Will discuss experiments aimed at probing signatures of viscous contributions to electrical transport in ultra pure metallic systems. The hydrodynamic regime was reached in semiconductor heterostructures in the 1990s, but has only recently come into reach in naturally occurring compounds. I will focus on our group's work on layered delafossite metals, but possibly also discuss results from other groups on different material families.
26. Nuclear Theory/RIKEN Seminar
"Factorization and phenomenology for Transverse Momentum Dependent distributions"
Friday, August 18, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
Factorization and phenomenology for Transverse Momentum Dependent distributions Abstract: The factorization of the hadronic part of the cross sections plays a central role in our comprehension of collider physics. I will review some aspects of the factorization, like the appearence of rapidity divergences and the related subtractions and log resummation (up to higher orders in QCD perturbative expansion) in transverse momentum dependent cross sections. As an application I will describe the inclusion of the TMD formalism in an analysis of vector boson production data.
27. RIKEN Lunch Seminar
"Revisit the energy density and the gluon spectrum in the boost-invariant Glasma from a semi-analytic approach"
Presented by Ming Li
Thursday, August 17, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: '''Hiromichi Nishimura'''
In high energy heavy-ion collisions, the soft degrees of freedom at the very initial stage after the collision can be effectively represented by strong classical gluonic fields within the Color Glass Condensate framework. Understanding the space-time evolution of the system is equivalent to solving the classical Yang-Mills equations for the gluonic fields. There have been many efforts in the past two decades in numerically solving these equations. In this talk, on the contrary, I will use a semi-analytic approach that assumes the solution has the form of a power series expansion in the proper time. I will discuss the energy-momentum tensor and the gluon spectrum obtained from this approach and make comparisons with the numerical results in the literature.
28. Special Nuclear Theory Seminar
"Gluon orbital angular momentum at small-x"
Presented by Yoshitaka Hatta, YITP, Kyoto University
Wednesday, August 16, 2017, 10:30 am
Small Seminar Room, Bldg. 510
Hosted by: 'Raju Venugopalan'
After reviewing the general aspects of the partonic orbital angular momentum in QCD (rigorous definition, connection to the Wigner distribution, etc), I focus on the gluon OAM in the small-x regime and discuss its measurability and a possible relation to the polarized gluon distribution.
29. Nuclear Theory/RIKEN Seminar
"Resummation of nonglobal logarithms in QCD"
Presented by Yoshitaka Hatta, Kyoto University
Friday, August 11, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
The large angle emission of soft gluons from QCD jets gives rise to the so-called nonglobal logarithms. In this talk I discuss the resummation of nonglobal logarithms at finite Nc with particular emphasis on its deep connection to the small-x logarithms in high energy scattering.
30. Brookhaven Lecture
"516th Brookhaven Lecture: 'From NSLS to NSLS-II and Beyond: Accelerator Physics Challenges'"
Tuesday, August 8, 2017, 4 pm
Berkner Hall Auditorium
Hosted by: ''Larry Carr''
31. Nuclear Theory/RIKEN Seminar
"General formulae for dipole Wilson line correlators with the Color Glass Condensate"
Presented by Kenji Fukushima, University of Tokyo
Friday, August 4, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
I talk about general formulae to compute Wilson line correlators with the Color Glass Condensate approximated by the McLerran-Venugopalan model. Specifically, as an application, I explain about a perturbative expansion of the dipole correlators in terms of 1/N_c to derive fully analytical expressions. I finally discuss the validity of the large-N_c expansion by calculating the higher-order harmonics of the flow observables in the dipole model.
32. NSLS-II Friday Lunchtime Seminar Series
"From Particles to Patients: The Role of an Epoxide Hydrolase in P. Aeruginosa Virulence"
Presented by Kelli Hvorency, 2017 Julian D. Baumert. PhD. Thesis Award Winner, Dartmouth College
Friday, August 4, 2017, 12 pm
NSLS-II Bldg 743 (LOB 3), room 156
Hosted by: ''Ben Ocko, Shirish Chodankar, Milinda Abeykoon, Juergen Thieme and Guimei Wang''
33. Particle Physics Seminar
"Latest Results from NOvA"
Presented by Louise Suter, Fermilab
Thursday, July 27, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Xin Qian''
NOvA is a long-baseline neutrino experiment which utilizes two basically fully active, finely segmented, liquid scintillator detectors: a Near Detector located at Fermilab, and a Far Detector located in Ash River, MI, and situated roughly 14 mrad off Fermilab's NuMI beam. Using this narrow-band beam of mostly muon neutrinos we study the oscillation of these neutrinos over the 810 km baseline to measure the rate of electron neutrino appearing and of muon neutrinos and neutral current interactions disappearing between the two detectors. These are interpreted to give our latest measurements on the neutrino mass ordering, CP violation, the flavor content of the third neutrino mass eigenstate, and tests of the three-neutrino paradigm.
34. Computational Science Initiative Event
"The AMReX Astrophysics Suite: Simulating the Stars at the Exascale"
Presented by Michael Zingale, Associate Professor, Dept. Of Physics and Astronomy, Stony Brook University
Thursday, July 27, 2017, 1:30 pm
Seminar Room, Bldg. 725
Hosted by: 'Meifeng Lin'
Astronomy is an observational science — we take data (primarily light) from the objects in the Universe and use this to infer how systems work. Astrophysical simulations allow us to perform virtual experiments on these systems, giving us the ability to see into stars in a way that light alone does not allow. Stellar systems can be modeled using the equations of hydrodynamics, together with nuclear reactions, self-gravity, complex equations of state, and at times, radiation (and magnetic fields). The resulting simulation codes are multiphysics and multiscale, and a variety of techniques have been developed to permit accurate and efficient simulations. We describe the adaptive mesh refinement (AMR) codes for astrophysics built upon the AMReX library: the AMReX Astrophysics Suite. We'll focus on the codes for stellar / nuclear astrophysics: Maestro and Castro. Maestro models subsonic stellar flows while Castro focuses on highly-compressible flows. They share the same microphysics (reaction networks, equations of state) and parallelization strategy. Through AMReX, we distribute boxes in our AMR hierarchy across nodes and we use OpenMP (via a logical tiling model in Castro) to spread the work on a box across cores in a node. Recently we've implemented a GPU strategy in AMReX that allows us to move the computational kernels onto GPUs to offload expensive calculations. We'll discuss the current performance of the hydrodynamics and reaction networks on GPUs and how our strategy will evolve in the future.
35. Environmental & Climate Sciences Department Seminar
"Classifying Aerosol Particles with a Centrifugal Particle Mass Analyzer (CPMA)"
Presented by Kristen Okorn, Stevens Institute of Technology (SULI Student Summer 2017)
Thursday, July 27, 2017, 11 am
Conference Room Bldg 815E
Hosted by: 'Ernie Lewis'
Although wood stoves are a carbon-neutral renewable energy source, they are the largest source of particulate matter (PM) emissions in New York State. A Differential Mobility Analyzer (DMA), which classifies particles by their mobility diameter, has traditionally been employed to characterize such particulate emissions. However, because the black carbon (BC) particles produced by combustion that contribute to PM are fractal, their mobility diameters are not equal to their mass-equivalent diameters. In contrast to the DMA, the Centrifugal Particle Mass Analyzer (CPMA) classifies aerosol particles by their mass, using two rotating cylinders and an electric potential; when the centrifugal and electrostatic forces on a particle are equal, it passes through. The CPMA can select particles with masses ranging from 2×10 4 to 1.05×103 fg (corresponding to diameters, for particles with density 1 g cm 3, ranging from 7 to 1300 nm). It can be operated in two different ways: the "Run" classification method can be used to select for a single particle mass, and the "Step Scan" method can be used to select particles over a set range of masses. A neutralizer must be used upstream of the CPMA to create a charge distribution on particles before they enter the instrument. A DMA can optionally be used to pre-select particles of a specific mobility diameter before entering the CPMA. Downstream of the instrument, a Condensation Particle Counter (CPC) must be used in order to determine the number concentration of particles that pass through the CPMA. The basic operating principles of the CPMA are discussed, and results are presented for its characterization of polystyrene latex (PSL) particles, ammonium sulfate particles, and emissions from a wood burning stove.
36. Particle Physics Seminar
"W boson mass measurement with the ATLAS experiment"
Presented by Fabrice Balli, CEA Saclay
Thursday, July 20, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Alessandro Tricoli'
The W boson mass is a fundamental parameter of the Standard Model (SM) and was measured by several experiments at high energy e+e- and ppbar colliders. This parameter's measurement has the biggest impact on indirect searches for new particles or interactions, by comparing the measurement of this parameter with the prediction from the SM. It was measured recently by the ATLAS experiment at LHC, using data recorded in 2011, with a centre of mass energy of 7 TeV. I will review the thorough work that was performed in the ATLAS collaboration for this measurement and will discuss some considerations for future measurements at the LHC.
37. NSLS-II Friday Lunchtime Seminar Series
"Bio-cryo Electron Microscopy: The Opportunity and Plan" and "Characterizing Self-Assembled Nanoparticles Employed in Drug Delivery Systems"
Presented by Sean McSweeney and Kazuo Sakurai, NSLS-II, BNL and University of Kitakyushu
Friday, July 14, 2017, 12 pm
NSLS-II Bldg 743 (LOB 3), room 156
Hosted by: ''Ben Ocko, Shirish Chodankar, Milinda Abeykoon, Juergen Thieme and Guimei Wang''
38. Physics Colloquium
"Anomalies in Reactor Neutrinos"
Presented by Chao Zhang, BNL
Tuesday, July 11, 2017, 3:30 pm
Large Seminar Room, Bldg. 510
Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactor neutrinos have played a major role in the discovery of neutrinos and neutrino oscillations. However, recently there emerged a few anomalies from reactor neutrino experiments when compared with state-of-the-art model predictions. The anomalies include a 5.5% deficit of the integrated antineutrino flux, a discrepancy in the antineutrino prompt energy spectrum around 5 MeV, and a 7.8% deficit in the 235U antineutrino flux from the new fuel evolution analysis in the Daya Bay Experiment. In this talk, those anomalies and their implications will be discussed. A new reactor neutrino experiment, PROSPECT, is aiming to resolve the anomalies by precisely measuring the 235U antineutrino spectrum at a very short baseline. The status of the PROSPECT experiment will also be reported
39. Office of Educational Programs Event
"High School Research Program Begins"
Monday, July 10, 2017, 8:30 am
Hamilton Seminar Room, Bldg. 555
40. Nuclear Theory/RIKEN Seminar
"Holographic Pomeron: Scattering, saturation, entropy and black hole."
Presented by Ismail Zahed, Stony Brook
Friday, July 7, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
I will discuss the general nature of the holographic Pomeron as a quantum QCD string exchange in both flat and curved AdS space for both pp and ep collisions at either large energies or small x. This description leads naturally to the concept of wee-strings and their distribution both in rapidity and transverse space. The holographic Pomeron carries intrinsic temperature and entropy, with the latter being identical to the recently reported entanglement entropy. I will show that this non-perturbative description of the Pomeron cross over to the the perturbative one, with a phase boundary dominated by string balls, i.e. long and massive strings near their intrinsic Hagedorn temperature. These string balls lead to a distribution of large multiplicity pp events that is in agreement with the one reported for pp collisions at the LHC. I will show that at low-x, the quantum string is so entangled that very weak string self-interactions can cause it to turn to a black hole. I will suggest that low-x saturation occurs when the density of wee-strings reaches the Bekenstein bound, with a proton size that freezes with increasing rapidity.
41. Nuclear Theory/RIKEN Seminar
"Probing Transverse Momentum Broadening in Heavy Ion Collisions"
Presented by Feng Yuan, LBL
Friday, June 30, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
In this talk, we will discuss the dijet azimuthal de-correlation in relativistic heavy ion collisions as an important probe of the transverse momentum broadening effects in heavy ion collisions. We take into account both the soft gluon radiation in vacuum associated with the Sudakov logarithms and the jet PT-broadening effects in the QCD medium. We find that the Sudakov effects are dominant at the LHC, while the medium effects can play an important role at RHIC energies. This explains why the LHC experiments have not yet observed sizable PT-broadening effects in the measurement of dijet azimuthal correlations in heavy ion collisions. Future investigations at RHIC will provide a unique opportunity to study the PT-broadening effects and help to pin down the underlying mechanism for jet energy loss in a hot and dense medium.
42. Nuclear Physics Seminar
"Measurement of longitudinal flow correlations in 2.76 and 5.02 TeV Pb+Pb collisions with the ATLAS detector"
Presented by Peng Huo, Stony Brook University
Tuesday, June 27, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Jin Huang'
Longitudinal dynamics has recently become a topic of great interest in the study of ultra-relativistic heavy ion collisions. Measurement of the longitudinal fluctuations of the flow harmonic coefficients $v_n$ and event-plane angles $\Psi_n$ can provide a more complete picture of space-time evolution of the hot, dense medium formed in heavy ion collisions. Longitudinal flow decorrelations can be modeled with two contributions: magnitude fluctuations and event plane twist. However, existing observables do not separate these two effects. In this analysis, a new 4-particle correlator is used to separate the event-plane twist from magnitude fluctuations in 2.76 and 5.02 Pb+Pb collisions. Results show both effects have a linear dependence on pseudorapidity separation for $v_{2-5}$, and show a small but measurable variation with collision energy. The correlation of $\Psi_n$ of different order are also expected to have longitudinal fluctuations due to the non-linear mixing effects between lower and higher order flow harmonics. First measurement of such non-linear mode-mixing effects as a function of pseudorapidity is also presented. These result will help to constrain initial conditions along longitudinal direction and also help understand the longitudinal evolution of the fireball.
43. Condensed-Matter Physics & Materials Science Seminar
"Resonant inelastic X-ray scattering on "moderately correlated" quantum materials"
Presented by L. Andrew Wray, New York University
Thursday, June 22, 2017, 1 pm
ISB Bldg. 734 Conf. Rm. 201 (upstairs)
Hosted by: ''''Mark Dean''''
The resonant inelastic X-ray scattering (RIXS) technique is best known for significant breakthroughs in the investigation of strongly correlated materials such as cuprates. However, the rapid advancement of RIXS spectrographs has made it increasingly attractive to apply the technique to a broad range of quantum materials outside of this comfort zone. This talk will review lessons learned from our recent measurements on material systems that feature a balance of correlated and itinerant physics, including VO2, the hidden order compound URu2Si2, and Prussian blue analogue battery electrodes. RIXS spectra enable the first observation of important collective modes for these systems, and provide a look into how correlated electron symmetries are melted - or persist! - in relatively itinerant and covalent environments. The data also highlight the need for improved theoretical modeling and higher photon throughput to achieve deeper insights.
44. Condensed-Matter Physics & Materials Science Seminar
"Tailoring Lattice and Charge at Complex Oxide Nanostructures and Interfaces"
Presented by Xia Hong, University of Nebraska-Lincoln
Tuesday, June 20, 2017, 11 am
Bldg. 480, Conference Room
Hosted by: 'Yimei Zhu'
Capitalizing on the energy competition of charge itineracy with the strong electron-electron and electron-phonon couplings, nanoscale manipulation of the charge and lattice degrees of freedom in strongly correlated oxides can often lead to new functionalities that are inaccessible in the bulk form. In this talk, I will present our studies of the emerging phenomena at epitaxial correlated oxide nanostructures and hetero-interfaces that result from the nanoscale lattice and charge control. By creating nanoscale periodic depth modulation, we have achieved a 50-fold enhancement of the magnetic crystalline anisotropy in ultrathin colossal magnetoresistive (La,Sr)MnO3, which is attributed to a non-equilibrium strain distribution established in the nanostructures [1]. I will also discuss the intricate interplay between epitaxial strain and electric field effect in determining the correlated transport of the charge transfer type Mott insulator (Sm,Nd)NiO3 [2,3], and how the interfacial charge transfer between two correlated oxides can be exploited to effectively engineer the performance of ferroelectric-gated Mott transistors [4]. [1] A. Rajapitamahuni et al., PRL 116, 187201 (2016). [2] L. Zhang et al., JPCM 27, 132201 (2015). [3] L. Zhang et al., APL 107, 152906 (2015). [4] X. Chen et al., Adv. Mater, in press (2017).
45. Condensed-Matter Physics & Materials Science Seminar
"Laser-driven Pulsed Neutron Sources as a Potential Pool-side Characterization Tool for Nuclear Fuels"
Presented by Sven Vogel, Los Alamos National Laboratory
Monday, June 19, 2017, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: '''Emil Bozin'''
The unique advantages of neutrons for characterization of nuclear fuel materials [1] are applied at the pulsed spallation neutron source at LANSCE to accelerate the development and ultimately licensing of new nuclear fuel forms. Neutrons allow to characterize the crystallography of phases consisting of heavy elements (e.g. uranium) and light elements (e.g. oxygen, nitrogen, or silicon) [2]. The penetration ability in combination with comparably large (e.g. cm sized) beam spots provide microstructural characterization of typical fuel geometries for phase composition, strains, and textures from neutron diffraction. In parallel, we are developing energy-resolved neutron imaging and tomography with which we can complement diffraction characterization. This unique approach not only allows to visualize cracks, arrangement of fuel pellets in rodlets etc., but also characterization of isotope or element densities by means of neutron absorption resonance analysis [3]. Laser-driven pulsed neutron sources [4] have the potential to provide these capabilities "pool-side", e.g. at the Advanced Test Reactor at Idaho National Laboratory. Compared to proton accelerator driven spallation sources, requiring investments exceeding $1B, the investment cost for a laser-driven neutron source would be of the order of several$10M with the potential of similar flux to that of a smaller, earlier generation spallation neutron source. Compared to electron accelerator-driven neutron sources, the flux of a laser-driven source would be at least one order of magnitude higher. Compared to reactor neutron sources, the pulse structure of the laser-driven neutron source would enable unique characterization not possible with steady-state reactor neutrons. In this presentation, we provide an overview of our recent accomplishments in fuel characterization for accident-tolerant fuel consisting of uranium nitride/uranium silicide composite fuels as well as metallic fuels.
46. Nuclear Theory/RIKEN Seminar
"Better fitting through (fictitious) chemistry"
Presented by Pasi Huovinen, Uniwersytet Wroclawski
Monday, June 19, 2017, 10 am
Small Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
One of the puzzles we have faced at the LHC is why the thermal models apparently cannot properly fit the yield of protons. I will explore how the fit improves if we assume that nucleon-antinucleon annihilations freeze-out way later than all other number changing processes or if strange particles freeze-out before non-strange particles, and how this affects the final particle distributions in hydrodynamical calculations.
47. Nuclear Theory/RIKEN Seminar
"Exploring the phase structure and dynamics of QCD"
Presented by Jan Pawlowski, Heidelberg
Friday, June 16, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
The past years have seen tremendous progress in the description of Quantum Chromodynamics at vanishing and finite temperature and density with functional approaches, such as the functional renormalisation group or Dyson-Schwinger equations. Within these approaches QCD correlation functions of quarks, gluon and hadrons are computed non-perturbatively from first principles. In the talk I will discuss results for the phase structure of QCD at finite temperature and density, as well as for thermodynamical obserables such as the pressure and the trace anomaly. The approach is also applied to baryon number fluctuations. By now functional approaches also allow for a direct computation of transport coefficients in QCD. First results concern the temperature dependence of the shear viscosity over entropy ratio in Yang-Mills theory and QCD. The talk concludes with a discussion of the further prospects for our understanding of the phase structure and dynamics of QCD.
48. Particle Physics Seminar
"First Results from XENON1T"
Presented by Dr. Fei Gao, Columbia University
Thursday, June 15, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Xin Qian''
Understanding the properties of dark matter particle is a fundamental problem in particle physics and cosmology. The search of dark matter particle scattering off nuclei target using ultra-low background detector is one of the most promising technology to decipher the nature of dark matter. The XENON1T experiment, which is a dual phase detector with ~2.0 tons of xenon running at the Gran Sasso Laboratory in Italy, is designed to lead the field of dark matter direct detection. Since November 2016, the XENON1T detector is continuously taking data, with a background rate of more than one order of magnitude lower than any current generation dark matter search experiment. In this talk, I will present the first dark matter search results from XENON1T. Details about the XENON1T detector as well as the data analysis techniques will also be covered.
49. Condensed-Matter Physics & Materials Science Seminar
"A model of chiral spin liquids with tunable edge states"
Presented by Christopher Mudry, Paul Scherrer Institute, Switzerland
Thursday, June 15, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: 'Alexei Tsvelik'
We construct a quantum field theory in (2+1)-dimensional spacetime for strongly interacting Majorana fields that is amenable to a mean-field approximation. The mean-field phase diagram predicts the existence of two competing phases, one of which supports chiral non-Abelian topological order, while the other supports chiral Abelian topological order. The two mean-field phases are separated by a continuous phase transition. This quantum field theory captures the low-energy physics of quantum spin-1/2 localized on the sites of a lattice whose interactions are $SU(2)$ symmetric but break time-reversal symmetry. The lattice geometry can be interpreted as a one-dimensional stacking of two-leg ladders or as a bilayer of two square lattices. Both incompressible ground states can thus be thought of as chiral spin liquids in two-dimensional space supporting non-Abelian and Abelian topological order, respectively.
50. HET/RIKEN Seminars
"Searching for New Physics with Higgs Decays"
Presented by Daniel Stolarski, Carleton University
Wednesday, June 14, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Pier Paolo Giardino'
51. Particle Physics Seminar
"Hadronically interacting Dark Matter, and a new mechanism for the Baryon Asymmetry, within QCD"
Presented by Professor Glennys Reynolds Farrar, NYU
Wednesday, June 14, 2017, 10 am
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
There may be a so-far-undiscovered neutral, stable particle composed of 6 quarks, denoted S, with mass m_S ~ 2 m_p. If so, the S is an excellent Dark Matter candidate. More generally, I will discuss how hadronic-strength interaction between DM and baryons can cause local DM to co-rotate with gas and stars, resulting in DM energy deposits below threshold for direct detection. DM-baryon interactions cause rotation curves to reflect baryonic density profiles, as observed in some galaxies, and can help alleviate some of the issues with CDM at small scales. An open question is whether the measured Ly-alpha power spectrum places an upper limit on the DM-baryon cross section, which is sufficiently robust and constraining to rule out the co-rotation scenario. The S-DM scenario suggests a new mechanism for producing the observed baryon asymmetry, and appears capable of naturally explaining the DM to baryon ratio.
52. Physics Colloquium
"Stable Sexaquark as Dark Matter"
Presented by Professor Glennys Reynolds Farrar, NYU
Tuesday, June 13, 2017, 3:30 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
Dark Matter could be composed of an as-yet-undiscovered stable or essentially stable, neutral B=2 hadron composed of uuddss quarks. How such a particle, designated S for Sexaquark and to distinguish from the loosely bound di-Lambda called H-dibaryon, can be compatible with current knowledge is explained. The S is absolutely stable if m_S < 2 m_p+ 2 m_e. If m_S > 2 m_p+ 2 m_e but < m_p+m_e + m_Lambda, its lifetime could be longer than the age of the Universe. Experiments are proposed to discover and measure the mass of the proposed particle. To first approximation it behaves like standardl Cold Dark Matter, but some distinctive differences may help explain some puzzles about DM at galactic scales.
53. Nuclear Theory/RIKEN Seminar
"Gluon structure of hadrons and nuclei"
Presented by Phiala Shanahan, MIT
Friday, June 9, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
I will present the results of recent lattice QCD studies of the gluon generalised form factors of both hadrons and light nuclei. The generalised transversity gluon distributions are of particular interest since they are purely gluonic; they do not mix with quark distributions at leading twist. In light nuclei they moreover provide a clean signature of non-nucleonic degrees of freedom. The goal of these studies is to provide QCD predictions to be tested at an electron-ion collider (EIC) designed to access gluon structure quantities including transverse-momentum dependent distributions (TMDs) and gluon generalised parton distributions (GPDs).
54. RIKEN Lunch Seminar
"Anomalies and Exact Results In Massive Quantum Chromodynamics"
Presented by Zohar Komargodski, Stony Brook
Thursday, June 8, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Hiromichi Nishimura'
55. Nuclear Physics Seminar
"Anatomy of Azimuthal Angle Correlations in Large and Small Systems - Why the fuss?"
Presented by Roy Lacey, Stony Brook University
Tuesday, June 6, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Oleg Eyser'
Azimuthal momentum anisotropy measurements are ubiquitous at both RHIC and the LHC. However, there are pervasive misconceptions as to the mechanistic origin of this anisotropy in both small and large systems. In this talk, I will demonstrate how recent momentum anisotropy measurements, for a broad range of systems, have been leveraged to gain new mechanistic insights and to constrain the properties of the medium produced in these collisions. In particular, the role of final state effects versus initial state momentum domain effects in explanations of the measurements will be addressed.
56. Nuclear Theory/RIKEN Seminar
"Hydrodynamic Fluctuations in Heavy Ion Collisions"
Presented by Derek Teaney, Stony Brook
Friday, June 2, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
We develop a set of kinetic equations for hydrodynamic fluctuations which are equivalent to nonlinear hydrodynamics with noise. The hydrokinetic equations can be coupled to existing second-order hydrodynamic codes to incorporate the physics of these fluctuations. We use the hydrokinetic equations to analyze thermal fluctuations for a Bjorken expansion, evaluating the contribution of thermal noise from the earliest moments and at late times. In the Bjorken case, the solution to the kinetic equations determines the coefficient of the first fractional power of the gradient expansion $\sim 1/(\tau T)^{3/2}$ for the expanding system. Numerically, we find that the contribution to the longitudinal pressure from hydrodynamic fluctuations is larger than second-order hydrodynamics for typical medium parameters used to simulate heavy ion collisions. Subsequently we analyze the behaviour of hydrodynamic fluctuations of near the QCD critical point, and dilineate the relevance Kiblle-Zurek scaling relative to other physics. If time permits we will also describe how thermal fluctuations place a lower bound on the bulk viscosity of QCD. References: Y.~Akamatsu, A.~Mazeliauskas and D.~Teaney, A kinetic regime of hydrodynamic fluctuations and long time tails for a Bjorken expansion,'' [arXiv:1606.07742 [nucl-th]]. Y.~Akamatsu, D. Teaney, F. Yan, Y. Yin, Transitting the critical point,'' in progress.
57. Environmental & Climate Sciences Department Seminar
"Cloud radiative fraction: Determination by high resolution photography from the surface looking upward"
Presented by Stephen E. Schwartz, Environmental & Climate Sciences Department
Thursday, June 1, 2017, 11 am
Conference Room Bldg 815E
Clouds greatly affect short- and longwave radiation transfer in the atmosphere and consequently climate. Hence it is essential that the amount and radiative influences of clouds be accurately represented in climate models. The conventional measure of the amount of cloud in a grid cell is cloud fraction, CF, the fraction of the surface area covered by cloud. CF is a commonly reported meteorological quantity, with a long record of surface observations, greatly augmented in the past several decades by satellite observations. Global cloud fraction determined from satellite measurements has systematically increased with time, a consequence not of secular increase in cloud fraction but of an increase with time in the sensitivity of active and passive satellite instruments. Such a situation raises the question of whether CF can be defined and how well it can be measured. Commercially available digital cameras provide an unprecedented opportunity for detailed study of cloud structure from the surface, looking upward. Key attributes of such cameras include large number of pixels, (e.g., 3456 x 4608; 16 M pixel) yielding rich detail of spatial structure, high spatial resolution, and high dynamic range (16 bit in each of three color channels at visible wavelengths). In the work reported here two cameras were pointed vertically, typically with field of view FOV 21 × 29 mrad and 120 × 160 mrad, respectively, denoted here narrow field of view, NFOV, and wide field of view WFOV, corresponding, for cloud base at 1 km, to 21 × 29 m (NFOV) and 120 × 160 m (WFOV). For perspective, the FOV for the NFOV camera is 2 × 3 sun diameters and for the WFOV camera 11 × 15 sun diameters. Nominal angular dimension of a single pixel is 6 μrad for the NFOV camera and 34 μrad for the WFOV camera, corresponding, again for cloud height 1 km, to 6 mm and 34 mm, respectively. Such single-pixel resolution is some 3 to 5 orders of magnitude finer than that avai
58. Particle Physics Seminar
"Higgs boson properties: what we learn from run II of LHC"
Presented by Andrei Gritsan, Johns Hopkins University
Thursday, May 25, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Alessandro Tricoli'
During the second run in 2015-2016, LHC delivered the number of proton-proton collisions far beyond expectation and at higher energy than in run I. We will review the very first results on the H boson properties based on the full dataset collected by CMS by now. We will go through the four main topics: H boson couplings to gauge bosons, couplings to fermions, self-couplings, and search for an extended Higgs sector. Prospects of some of these measurements through the end of run III and phase II of LHC will be discussed.
59. RIKEN Lunch Seminar
"Mixed Anomaly and Global Consistency"
Presented by Yuya Tanizaki, RBRC
Thursday, May 25, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Hiromichi Nishimura'
Symmetry and topology are powerful tools to study strongly interacting dynamics. In this talk, we will see that mixed 't Hooft anomaly and global consistency strongly constrains the possible low-energy dynamics in a simple quantum mechanical example. I will briefly explain the same idea is useful to study the phase diagram of bifundamental gauge theories at finite theta angles.
60. HET/RIKEN Seminar
"Cosmology in Mirror Twin Higgs and Neutrinos"
Presented by Patrick Fox, Fermilab
Wednesday, May 24, 2017, 2 pm
Small Seminar Room, Bldg. 510
61. Nuclear Physics Seminar
"Searching for collectivity and testing the limits of hydrodynamics: results from the 2016 d+Au beam energy scan"
Presented by Ron Belmont, University of Colorado Boulder
Tuesday, May 23, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Jin Huang'
The standard picture of heavy ion collisions is that large systems (collisions of large nuclei like Au+Au and Pb+Pb) create a quark-gluon plasma that exhibits collective behavior indicative of nearly inviscid hydrodynamical evolution. Recently, data from small systems (collisions of a small projectile and a large target like d+Au and p+Pb) have been found to exhibit strikingly similar evidence for collective behavior. To further elucidate these results, RHIC delivered in 2016 a beam energy scan of d+Au collisions at 4 different energies: 200, 62.4, 39, and 19.6 GeV. In this talk we present a wide array of results from the Run16 d+Au BES and discuss the implications for collective behavior and the limits of applicability for hydrodynamics.
62. Particle Physics Seminar
"Tiny Bubbles in the Mine: New Results from the PICO-60 Dark Matter Detector"
Presented by Dr. Eric Dahl, North Western
Friday, May 19, 2017, 10 am
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
The PICO Collaboration builds bubble chambers for the direct detection of WIMP dark matter. These devices are unique among direct detection experiments both in the WIMP models they can probe and the backgrounds they face. The PICO collaboration has set consecutive world-leading direct-detection limits on the spin-dependent WIMP-proton cross section, most recently with a zero-background 1.2 ton-day exposure with a C3F8 target in the PICO-60 detector at SNOLAB. This result is significant not just because it reaches new WIMP parameter space, but also because it demonstrates our ability to eliminate the anomalous bubble nucleation background that limited past bubble chamber WIMP searches, opening the door for experiments at the ton scale and beyond. I will describe this new result from PICO, our immediate plans for new detectors at SNOLAB, and the broader role bubble chambers will play in the future of dark matter detection, including the new scintillating bubble chamber technology developed by my group at Northwestern.
63. RIKEN Lunch Seminar
"Probing quantum entanglement at the Electron Ion Collider"
Presented by Dima Kharzeev, BNL and Stony Brook University
Thursday, May 18, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Hiromichi Nishimura''
64. HET/RIKEN Seminars
"Collider and Cosmological Signatures of a Strong Electroweak Phase Transition"
Presented by Jonathan Kozaczuk, UMass Amherst
Wednesday, May 17, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Pier Paolo Giardino''
65. Physics Colloquium
"Direct Detection of sub-GeV Dark Matter"
Presented by Rouven Essig, Stony Brook University
Tuesday, May 16, 2017, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: 'Andrei Nomerotski'
Dark matter makes up 85% of the matter in our Universe, but we have yet to learn its identity. A broad array of search strategies are needed to probe for non-gravitational interactions between dark matter and ordinary matter. While most searches focus on Weakly Interacting Massive Particles (WIMPs) with masses between 1 GeV and 1 TeV, it is imperative to also consider other motivated dark matter candidates. In this talk, I will discuss dark matter with MeV-to-GeV masses, which is a theoretically and phenomenologically appealing possibility and presents a new frontier in the search for dark matter. I will highlight novel dark matter direct-detection strategies that can probe this under-explored mass range. I will describe how XENON10 data already probes dark matter with masses as low as a few MeV, and discuss improvements expected from new experiments using semiconductors or scintillators. This includes SENSEI, a new ultra-low-threshold silicon CCD detector, which is poised to probe vast new regions of parameter space in the next few years. I will also present a few simple benchmark models of MeV-to-GeV dark matter, and contrast direct-detection probes with searches at colliders and fixed-target experiments.
66. Condensed-Matter Physics & Materials Science Seminar
"Thin-Film Alchemy: Using Epitaxial Engineering to Unleash the Hidden Properties of Oxides"
Presented by Darrell G. Schlom, Cornell University
Monday, May 15, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: 'Ivan Bozovic'
Guided by theory, unparalleled properties—those of hidden ground states—are being unleashed by exploiting large strains in concert with the ability to precisely control dimensionality and stabilize metastable phases in epitaxial oxide heterostructures. For example, materials that are not ferroelectric or ferromagnetic in their unstrained state can be transmuted into materials that are both at the same time. Similarly, new tunable dielectrics with unparalleled performance have been created as well as a new single-phase multiferroic material where ferroelectricity and strong magnetic ordering are coupled near room-temperature. These are just three examples of the unparalleled properties—those of hidden ground states—being unleashed in epitaxial oxide heterostructures utilizing thin film alchemy
67. NSLS-II Friday Lunchtime Seminar Series
"Status of SSRF and the Shanghai X-FEL Projects, and Efforts in Single Particle Imaging and Whole Cell Imaging with X-FELs"
Presented by Thomas Earnest, Shanghai Synchrotron Radiation Facility
Friday, May 12, 2017, 12 pm
NSLS-II Bldg 743 (LOB 3), room 156
Hosted by: 'Ben Ocko and Shirish Chodankar'
68. RIKEN Lunch Seminar
"The nucleon axial charge from Lattice QCD"
Presented by Enrico Rinaldi, RBRC
Thursday, May 11, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Hiromichi Nishimura''
69. Nuclear Theory/RIKEN Seminar
"Probing nucleon substructure with Bayesian parameter estimation"
Presented by Scott Moreland, Duke
Friday, May 5, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
Multi-particle correlations observed in small collision systems at top LHC energies exhibit signatures which are similar to those observed in large collision systems and generally attributed to the formation of a deconfined quark-gluon plasma (QGP). This suggests that even proton-proton and proton-lead collisions may produce small droplets of QGP which translate spatial inhomogeneities into final-state momentum anisotropies. A primary challenge in testing hydrodynamic descriptions of small collision systems is in modeling the initial stages of the collision. In this talk, I discuss recent efforts to apply Bayesian methodology to parametric descriptions of initial state physics. I show that such methods can be extended to smaller length scales which include partonic degrees of freedom and glean information regarding the fluctuating nature of the proton.
70. Computational Science Initiative Event
"Frontiers for High Performance Computing in Cancer Research"
Presented by Dr. Eric A. Stahlberg, Frederick Nat Lab for Cancer Research
Friday, May 5, 2017, 10 am
Seminar Room, Bldg. 725
Hosted by: 'Frank Alexander'
Anticipated advances in high-performance computing are enabling exciting new areas of computational and data oriented cancer research. These frontiers are being explored in a unique collaboration between the US Department of Energy and the National Cancer Institute in the Joint Design of Advanced Computing Solutions for Cancer. While the three-year collaboration is still in its first year, the collaboration is providing tremendous insight into the promise and challenges of employing extreme scale computing to advance research in the challenging and complex problem of cancer. Challenged with the aim of providing predictive insight in areas such as tumor response to treatments, molecular level interactions, and even clinical outcomes, the collaborative effort advances the frontiers of cancer research and computing in both numerically-intensive and data-intensive applications, while providing insights into opportunities for the high-performance computing community overall.
71. Particle Physics Seminar
"New MEG Results and Prospects for Improved Searches for Muon and Electron Number Violation in the Charged Sector"
Presented by William Molzon, University of California, Irvine
Thursday, May 4, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
Searches for muon and electron number violation in the charged sector continue to be a sensitive probe of non Standard Model physics. I will give results of the full data-set of the MEG collaboration's search for muons decaying to electron plus photon and describe improvements to the MEG muon beam and apparatus that will improve sensitivity by a factor of ten in the next few years. I will also briefly review other experiments in the planning and early construction phases that are expected to improve sensitivity in related processes in the coming 5-10 years.
72. Condensed-Matter Physics & Materials Science Seminar
"Transient Dynamics of Strongly Correlated Electrons After Sudden Excitations"
Presented by Marco Schiro, Institut de Physique Theorique (IPhT), CEA, Saclay, France
Thursday, May 4, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: 'Robert Konik'
The development of pump-probe spectroscopies with femtosecond time resolution, which allows to track the dynamics of electronic degrees of freedom in solids under optical excitations, opens up a new window to understand strongly correlated materials and offers the intriguing possibility of controlling their properties with light, on ultra-fast time scales. Triggered by these advances, the interest around time dependent phenomena in quantum many body systems has recently substantially grown. In this talk will review recent progress in understanding transient dynamics of electrons in correlated metals, Mott Insulators and superconductors. I will show that quite generically these systems display very sharp dynamical transitions as a function of the external perturbation, in correspondence of which the lattice response and the sensitivity to density inhomogeneities can be greatly enhanced.
73. RIKEN Lunch Seminar
"Lattice study of gauge theory with multiple fermion representations"
Presented by Ethan Neil, University of Colorado, Boulder and RBRC
Thursday, May 4, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Enrico Rinaldi'
"There is long-standing theoretical interest in the behavior of a strongly-coupled gauge theory in the presence of multiple fermions charged under different representations of the gauge group. In addition to the question of whether generation of dynamically separated scales will occur, such theories appear commonly in UV realizations of composite Higgs models with partially composite top quarks. I will present a first lattice study of SU(4) gauge theory with fermions in each of the two lowest-lying representations, discussing the finite-temperature phase structure and low-lying spectrum. Connections to BSM physics through a particular composite Higgs model will also be made."
74. Joint YITP/HET Seminar
"Evidence for a ~17 MeV Particle in Rare Beryllium-8 Decays?"
Presented by Tim Tait, UCI
Wednesday, May 3, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Amarjit Soni''
75. Nuclear Theory/RIKEN Seminar
"Analyticity in Spin and Causality in Conformal Theories"
Presented by Simon Caron-Huot, McGill
Friday, April 28, 2017, 2 pm
Large Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
The conformal bootstrap aims to calculate scaling dimensions and correlation functions in various theories, starting from general principles such as unitarity and crossing symmetry. I will explain that local operators are not independent of each other but organize into analytic functions of spin, and I will present a formula, extending a classic one due to Froissart and Gribov in the early days of Regge theory, which quantifies the consequences of this fact. Applications will include a new way to solve crossing symmetry at large spin, as well as new bounds encoding bulk locality in theories with a gravity dual. Based on 1703.00278.
76. Condensed-Matter Physics & Materials Science Seminar
"Spin-liquids in novel triangular and kagome rare-earth magnets"
Presented by Martin Mourigal, Georgia Tech
Friday, April 28, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: '''Igor Zaliznyak'''
Insulating magnets combining the effects of geometrical frustration with strong spin-orbit coupling offer a prime route to realize correlated quantum states with exotic ground-states and excitations. Spin-space anisotropy and bond-directional magnetic exchange interactions are naturally present in rare-earth oxides. One of the most celebrated consequence is the existence of classical and quantum "spin-ice" physics in rare-earth pyrochlores, materials in which magnetic ions occupy a three-dimensional network of corner-sharing tetrahedra. In this talk, I will present the discovery of distinct flavors of exotic magnetic matter in families of rare-earth oxides with two-dimensional kagome [1] and triangular [2] geometries. This experimental work relies on recent advances in materials synthesis and combines thermodynamic characterization with state-of-the-art neutron scattering experiments to unravel the classical or quantum nature of these newly discovered quasi-two-dimensional spin-liquids. [1] Emergent order in the kagome Ising magnet Dy3Mg2Sb3O14, J. A. M. Paddison, H. S. Ong, J. O. Hamp, P. Mukherjee, X. Bai, M. G. Tucker, N. P. Butch, C. Castelnovo, M. Mourigal, and S. E. Dutton, Nature Communications 7, 13842 (2016). [2] Continuous excitations of the triangular-lattice quantum spin liquid YbMgGaO4, J. A. M. Paddison, M. Daum, Z. L. Dun, G. Ehlers, Y. Liu, M. B. Stone, H. D. Zhou, and M. Mourigal, Nature Physics AOP (2016).
77. Condensed-Matter Physics & Materials Science Seminar
"Magnetometry Study of Underdoped Cuprate YBa2Cu3O6.55"
Presented by Fan Yu, University of Michigan
Friday, April 28, 2017, 11 am
Bldg. 734, ISB. Conf. Rm. 168
Hosted by: '''''''Qiang Li'''''''
This talk would be focused on my study of the phase diagram of underdoped cuprate YBa2Cu3O6.55 using torque magnetometry as well as my exploration of extending magnetometry method into even higher magnetic fields (>45T) using pulsed magnet. The complex phase diagrams of cuprates are sometimes referred to as "competing orders", where a large variety of ordering tendencies are known to (co-)exist. Our experiment managed to reveal an anomaly on the magnetic susceptibility, which we believe was related to charge density wave transition. Particularly interesting is that this anomaly is observed in the strong diamagnetic regime where vortex liquid exists. We believe this should be considered as a direct experimental evidence for the picture of "competing orders". To further our understanding of the quantum vortex liquid, experiments at mK temperatures and at magnetic field exceeding 40 Tesla are necessary. During my PhD study, considerable amount of time was devoted to developing a reliable magnetometry method utilizing the pulsed magnet at NHMFL, Los Alamos. I would like to present my trail-and-error as well as the proposition of "time-delayed probe design", which should be able to bypass the inherent noise of a pulsed environment.
78. Particle Physics Seminar
"CP violation in neutrino oscillations and impact of new physics"
Presented by Dr. Poonam Mehta
Friday, April 28, 2017, 10 am
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
The study of CP violation addresses fundamental questions such as - are the laws of physics the same for matter and anti-matter. CP is a discrete symmetry of nature given by a product of two quantities : charge conjugation (C) and parity (P). Detecting leptonic CP violation is one of the most challenging goals in particle physics today. An attractive possibility to measure CP phase is via long baseline accelerator experiments such as Deep Underground Neutrino Experiment (DUNE). In this talk, we will show that clean extraction of CP violating phase becomes a formidable task in presence of new physics and one needs to devise ways to distinguish between standard paradigm and the new physics scenarios.
79. Particle Physics Seminar
"Searching for Optical Counterparts to Gravitational Wave Events in the Dark Energy Survey"
Presented by Jim Annis, Fermilab
Thursday, April 27, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Erin Sheldon'
80. Physics Colloquium
"Current Status of Neutrinoless Double Beta Decay Research"
Presented by Bob McKeown, Jefferson Lab
Tuesday, April 25, 2017, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: 'Andrei Nomerotski'
The observation of neutrinoless double beta decay would establish that neutrinos are Majorana fermions and would represent a discovery of profound importance: that lepton number is not conserved. There is currently a worldwide effort to search for neutrinoless double beta decay, using a variety of candidate isotopes and detector technologies. A subcommittee of the Nuclear Science Advisory Committee (NSAC) recently surveyed the field and the associated research and development needs. Based on the information provided to this subcommittee, I will present an overview of the present activity in this field and the prospects for the future.
81. Nuclear Theory/RIKEN Seminar
"Forward particle production in pA: implementing the NLO hybrid formalism"
Presented by Tuomas Lappi, University of Jyväskylä
Friday, April 21, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
Single inclusive particle production cross sections in high energy hadron collisions at forward rapidity are an important benchmark process for the CGC picture of small x QCD. The process can be calculated in the "hybrid formalism", where a collinear large-x quark or gluon scatters off the dense color field of the target. Recent calculations at next-to-leading order in perturbation theory have not led to a stable physical result for the single inclusive cross section at high transverse momenta. The problem with these NLO calculations lies in the subtraction procedure for the soft "rapidity" divergence which must be absorbed into BK renormalization group evolution of the target. This talk discusses recent work to understand and resolve the problems with the subtraction procedure. In particular, we have recently implemented numerically the quark channel production cross section using a new rapidity factorization procedure proposed by Iancu et al. For a fixed coupling one does indeed obtain a physically meaningful cross section which is positive and reduces in a controlled way to previous leading order calculations. However, it is not yet clear how to generalize this to running coupling in a way that is fully consistent with previous leading order calculations in coordinate space.
82. Particle Physics Seminar
"Searching for Our Milky Way's Dark Companions"
Presented by Alex Drlica- Wagner, Fermilab
Thursday, April 20, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Erin Sheldon''
Our Milky Way galaxy is surrounded by a multitude of dwarf satellite galaxies. They are some of the oldest, least luminous, most metal poor, and most dark-matter-dominated objects known. These extreme objects provide a unique opportunity for testing the standard models of cosmology and galaxy formation. In addition, the relative proximity and large dark matter content of dwarf galaxies make them excellent systems for probing the fundamental properties of dark matter. Over the past two years, the unprecedented sensitivity of the Dark Energy Camera has allowed us to nearly double the known population of Milky Way satellites. These discoveries help address the "missing satellites problem" and can be used to test the particle nature of dark matter. However, they also raise new questions concerning the role of the Magellanic Clouds in the formation of the Milky Way's satellite population. I will summarize recent results, outstanding questions, and upcoming advances in the study of the Milky Way's dark companions.
83. Condensed-Matter Physics & Materials Science Seminar
"Unpaired Spins in Superconductors: From Assassin to Enabler"
Presented by Jeffrey Lynn, NIST Center for Neutron Research, National Institute of Standards and Technology
Thursday, April 20, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: ''''Igor Zaliznyak''''
The magnetic properties of superconductors have a rich and interesting history, and we will briefly review some highlights. Early work showed that even tiny concentrations of magnetic impurities destroyed the superconducting pairing through the exchange-driven spin depairing mechanism, prohibiting any possibility of magnetic order coexisting with superconductivity. The first exceptions to this rule were provided by the cubic rare-earth substituted CeRu2 alloys, followed by the ternary Chevrel-phase superconductors (e.g. HoMo6S8) and related compounds, where long range magnetic order coexists or competes with superconductivity. The very low magnetic ordering temperatures (~1 K) suggested that dipolar rather than exchange interactions dominate, thus (it was thought) allowing the coexistence. These materials also provided the first examples of the competition between ferromagnetism and superconductivity. In the newer borocarbide class of magnetic superconductors (e.g. ErNi2B2C), however, it became clear that the magnetic order is in fact exchange driven. The borocarbides also provided the first example of the spontaneous formation of flux quanta (vortices). For the cuprate and iron-based superconductors (formerly known as "high Tc") we now have come full circle, as the spins are not only tolerated but are intimately tied to the superconductivity. The "parent" cuprate systems are Mott-Hubbard antiferromagnetic insulators with very strong magnetic interactions that are two-dimensional in nature. These strong exchange interactions survive into the superconducting state, yielding highly correlated electrons that participate directly in the superconducting pairing. The "parent" materials of the new iron-based high TC superconductors are also antiferromagnets with very energetic spin excitations, and in the superconducting regime they form a "magnetic resonance" that is directly tied to the superconducting order parameter, ju
84. Particle Physics SB/BNL Joint Cosmo seminar
"TBD"
Presented by Kyle Story, Stanford
Wednesday, April 19, 2017, 3 pm
Stony Brook University
85. Condensed-Matter Physics & Materials Science Seminar
"Listening to the hydrodynamic noise of Dirac fluid in graphene"
Presented by Kin Chung Fong, Raytheon BBN Technologies and Harvard University
Tuesday, April 18, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: 'Qiang Li'
Interactions between the Dirac fermions in graphene can lead to new collective behavior described by hydrodynamics. By listening to the Johnson noise of the electrons, we are able to probe simultaneously the thermal and electrical transport of the Dirac fluid and observe how it departs from Fermi liquid physics. At high temperature near the neutrality point, we find a strong enhancement of the thermal conductivity and breakdown of Wiedemann-Franz law in graphene. This is attributed to the non-degenerate electrons and holes forming a strongly coupled Dirac fluid. At lower temperatures beyond the hydrodynamic behavior, the Dirac fermions are in extreme thermal isolation with minute specific heat that can be exploited for ultra-sensitive photon detection. We will present our latest experimental result towards observing single microwave photons and explore its role in scaling up the superconducting qubit systems. Our model suggests the graphene-based Josephson junction single photon detector can have a high-speed, negligible dark count, and high intrinsic quantum efficiency for applications in quantum information science and technologies. Ref: Science 351, 1058 (2016)
86. Nuclear Physics Seminar
"Search for the Chiral Magnetic Effect at RHIC : challenges and opportunities"
Presented by Prithwish Tribedy, BNL
Tuesday, April 18, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Jia Jiangyong'
In this talk I will discuss about the ongoing and future efforts at RHIC towards the search for the Chiral Magnetic Effect (CME). I will focus on the recent STAR measurements of the charge separation across the reaction plane, a predicted signal of the Chiral Magnetic Effect. Although charge separation has been observed, it has been argued that the measured separation in A+A collisions can be explained by elliptic flow related backgrounds. I will discuss on the challenges in disentangling such background contributions from the signals of CME. I will also discuss on implications of the recent measurements of charge separation in p+A collisions towards the search for CME.
87. Nuclear Theory/RIKEN Seminar
"Effect of magnetic field on flow fluctuations in"
Presented by Ajit M. Srivvastava
Friday, April 14, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
Very strong magnetic fields can arise in non-central heavy-ion collisions at ultrarelativistic energies, which may not decay quickly in a conducting plasma. We carry out magnetohydrodynamics simulations to study the effects of this magnetic field on the evolution of the plasma and on resulting flow fluctuations. Our results show that magnetic field leads to enhancement in elliptic flow, while flow fluctuations lead to reorganization of magnetic flux resulting in a transient increase in the local magnetic field. We also show generation of vorticity arising from nontrivial dependence of magnetosonic waves on pressure gradients and magnetic field direction. Magnetic field from collision of deformed nuclei shows very nontrivial features and can lead to qualitatively new effects on plasma evolutions. We discuss possibility of dynamo effect in the presence of vortices if any exotic high baryon density QCD phases are achieved in heavy-ion collisions.
88. Particle Physics Seminar
"Natural Seesaw in Warped/Composite Higgs framework and its LHC Signals"
Presented by Kaustubh Agashe, University of Maryland
Thursday, April 13, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Christoph Lehner''
I will show how a natural seesaw model for SM neutrino mass arises within the general framework of a warped extra dimension (dual to composite Higgs in 4D). It starts out as an attempt at implementing the high-scale seesaw mechanism. I will first carefully determine what the underlying dynamical picture really is. Motivated by this physical understanding, LHC signals of TeV-mass SM singlet neutrinos within a specific model for the electroweak gauge sector will be discussed. Some of these channels are similar to those studied in 4D left-right (LR) symmetric models, but nonetheless the two can be distinguished. While other signals are more characteristic of the 5D/composite framework, i.e., are absent in 4D LR models.
89. Condensed-Matter Physics & Materials Science Seminar
"Electronic Squeezing of Pumped Phonons: Negative $U$ and Transient Superconductivity"
Presented by Dante Kennes, Columbia University
Thursday, April 13, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: '''Neil Robinson'''
Advances in light sources and time resolved spectroscopy have made it possible to excite specific atomic vibrations in solids and to observe the resulting changes in electronic properties but the mechanism by which phonon excitation causes qualitative changes in electronic properties has remained unclear. Here we show that the dominant symmetry-allowed coupling between electron density and dipole active modes implies an electron density-dependent squeezing of the phonon state which provides an attractive contribution to the electron-electron interaction, independent of the sign of the bare electron-phonon coupling and with a magnitude proportional to the degree of laser-induced phonon excitation. Reasonable excitation amplitudes lead to non-negligible attractive interactions that may cause significant transient changes in electronic properties including superconductivity. The mechanism is generically applicable to a wide range of systems, offering a promising route to manipulating and controlling electronic phase behavior in novel materials.
90. Nuclear Physics Seminar
"Systematic study of hadron production in highly asymmetric collisions at PHENIX"
Presented by Norbert Novitzky, Stony Brook University
Tuesday, April 11, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Jin Huang'
The observation of long range correlations in highly asymmetric systems as in p+Pb and d+Au collisions suggests the creation of a medium with collective behavior. Single particle production has proven to be a valuable tool to probe the quark-gluon plasma formed in heavy ion collisions as it is sensitive to energy loss, modifications of the nuclear wavefunction. It is an open question whether the apparent medium in small-on-large collisions and the QGP in large-on-large collisions is indeed the same, as is the role of the dynamics of the projectile (nucleon) wavefunction. In order to address these questions with a systematic study of highly asymmetric collisions, the RHIC collider provided beams for p+Al, p+Au, d+Au and 3He+Au collisions. The hadron production as a function of transverse momentum (pT) and rapidity can provide us very useful information about the evolution of the initial state and medium formation with system size. We will present the neutral pion and charged hadron measurements at forward, mid- and backward rapidities and discuss the implications of the results.
91. Nuclear Theory/RIKEN Seminar
"Anisotropic dissipative fluid dynamics - foundations & applications in heavy-ion physics"
Presented by Professor Dirk Rischke, Johann Wolfgang Goethe-Universität
Friday, April 7, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
In collisions of heavy ions at ultrarelativistic energies, a system of hot and dense strongly interacting matter is created. This matter exhibits a surprisingly strong degree of collectivity, implying a short mean free path of its constituents and, consequently, a small shear viscosity-to-entropy density ratio. This allows to describe the evolution of the system using relativistic dissipative fluid dynamics. Dissipative fluid dynamics can be understood as an expansion around local thermodynamical equilibrium, corresponding to the ideal-fluid limit where dissipative corrections are absent. A short mean free path means that this expansion is well defined and converges sufficiently rapidly. Nevertheless, in the initial stage of a heavy-ion collision, space-time gradients of the fluid-dynamical fields (energy-momentum and net-charge densities) are so large that dissipative corrections to the ideal-fluid limit can become sizable. In this situation, novel approaches to relativistic dissipative fluid dynamics are called for. One such approach is anisotropic dissipative fluid dynamics, which is based on an expansion around an anisotropic non-equilibrium state (instead of local thermodynamical equilibrium, as in conventional dissipative fluid dynamics). In this talk, I present a derivation of the equations of motion of anisotropic dissipative fluid dynamics from the Boltzmann equation, using the method of moments. I also discuss how to resolve an ambiguity to close the system of equations of motion in the case when there are no corrections to the anisotropic state which constitutes the basis of the moment expansion.
92. Instrumentation Division Seminar
"Next Generation Readout Electronics: Highly Integrated, High Performance and Low Cost Data Acquisition for Future Instrumentation Needs"
Presented by Isar Mostafanezhad, Nalu Scientific, LLC
Thursday, April 6, 2017, 2:30 pm
Large Conference Room, Bldg. 535
In this presentation, we discuss recent progress in high channel count data acquisition systems for large experiments. In recent years Nalu Scientific has established a new model for integration of readout electronics with detectors for HEP/NP applications. The most recent work has been involvement in the commissioning of the Belle II Time of Propagation Klong and Muon subdetectors at KEK in Japan. These innovations resulted in modern, modular, compact and high performance readout systems. Nalu Scientific, under multiple SBIR awards, has been working to commercialize these technologies to become available as off-the-shelf products for future experiments. We will cover: 1. Summary of Belle II TOP PID and KLM subdetectors 2. High performance, highly integrated, low cost readout 3. Current efforts in high resolution/ high performance timing 4. Specialized compact readout electronics for SiPMs
93. A Special HET/RIKEN Lunch Seminar
"The Road to Nuclear Physics from Standard Model"
Presented by Zohreh Davoudi, MIT
Thursday, April 6, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Hiromichi Nishimura''
At the core of nuclear physics is to understand complex phenomena occurring in the hottest and densest known environments in nature, and to unravel the mystery of the dark sector and other new physics possibilities. Nuclear physicists are expected to predict, with certainty, the reaction rates relevant to star evolutions and nuclear energy research, and to obtain the "standard" effects in nuclei to reveal information about the "non-standard" sector. To achieve such certainty, the field has gradually started to eliminate its reliance on the phenomenological models and has entered an era where the underlying interactions are "effectively" based on the Standard Model of particle physics, in particular Quantum Chromodynamics (QCD). The few-nucleon systems can now emerge directly from the constituent quark and gluon degrees of freedom and with only QCD interactions in play, using the numerical method of lattice QCD. Few-body observable, such as few-nucleon interactions and scattering amplitudes, as well transition amplitudes and reaction rates, have been the focus of this vastly growing field, as once obtained from QCD, and matched to effective field theories, can advance and improve the nuclear many-body calculations of exceedingly complex systems. This talk is a brief introduction to this program and its goals, with a great focus on the progress in few-body observables from QCD.
94. HET Seminar
"Hints of New Physics in Semi-leptonic B-meson Decays"
Presented by Diptimoy Ghosh, Weizman
Wednesday, April 5, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Amarjit Soni''
In recent years, a number of interesting signals of potential new physics in semi-leptonic B-meson decays have been reported both by the B-factories as well as the LHCb. In this talk, I will discuss these observations with a particular emphasis on the observable $R_{D^*}$, the ratio of the branching fraction of $\bar{B} \to D^* \tau \bar{\nu}_\tau$ to that of $\bar{B} \to D^* \ell \bar{\nu}_\ell (\ell = \mu, e )$, which shows a 3.3 sigma deviation from the Standard Model prediction. I will present an effective field theory analysis of these potential new physics signals and discuss possible ways to distinguish the various operators.
95. Nuclear Physics Seminar
"New insights to the search for the anomalous chiral effects using small colliding system at the LHC"
Presented by Zhoudunming Tu, Rice University
Tuesday, April 4, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Jiangyong Jia'
In relativistic heavy ion collisions, anomalous chiral effects have been predicted to occur in presence of a strong magnetic field induced by the spectator protons, e.g., the chiral magnetic effect (CME) and chiral magnetic wave (CMW). In the past decade, measurements of CME and CMW have been attempted from RHIC to the LHC energies, where significant signals were found to be in line with expectations of the chiral effects. However, soon after the initial excitement, various sources of background effects were identified and proposed to qualitatively describe the data. The origin of the backgrounds has been extensively studied, but still remains inconclusive to date. Recently, novel collective phenomenon has been found in high-multiplicity pA collisions, similar to those in AA collisions. Due to the weak correlation between the magnetic field direction and the event plane, the high-multiplicity pPb data are expected to have much suppressed CME and CMW signal, comparing to that in PbPb collisions, and thus provide an ideal testing ground to observables related to the anomalous chiral effects. In this talk, I will present new measurements related to the CME and CMW from CMS in pPb and PbPb collisions at the LHC, and discuss their implications to the search for the anomalous chiral effects including an outlook for future studies.
96. Instrumentation Division Seminar
"Ultrafast imaging technology: from visible light to high-energy X-ray photons"
Presented by Zhehui Wang, LANL
Friday, March 31, 2017, 2:30 pm
Large Conference Room, Bldg. 535
We are now in the era of ultrafast imaging, which is the ability to observe transient events with a time duration no longer than 100 ps (one billionth of the time for eye blinking). Innovative methods have demonstrated photography at the mind-bending speed of one trillion frames per second. Several recent advances make ultrafast imaging possible: ultrashort lasers and X-rays for illumination, abilities to harvest ultrafast responses in materials for efficient photon and electron detection, innovative ways to store and process data. It will be shown that ultrafast imaging technology is a natural fit to mesoscopic science. Meanwhile, ultrafast imaging technology also permits photography of macroscopic objects around the corner or hidden away from the direct line of sight. One recent LANL interest in ultrafast high-energy X-ray imaging is driven by MaRIE. Some material challenges will be highlighted towards a GHz frame-rate burst mode camera for photons at above 30 keV energies.
97. Particle Physics Seminar
"neutrinoless double beta decay and nuclear structure theory"
Presented by Professor Petr Vogel, Caltech
Friday, March 31, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: '''Xin Qian'''
Search for the neutrinoless double beta decay is one of the main goals of nuclear physics community worldwide. If observed, it would be an example of "physics beyond the Standard Model", showing that the lepton number is not a conserved quantity and that neutrinos are massive Majorana fermions. After introducing the subject and its particle physics consequences I will concentrate on the issue of evaluation of the nuclear matrix elements. Despite decades of effort and hundreds of publications, different approaches give results that differ by roughly a factor of three, and it is difficult to decide which of them is the most realistic. I will describe the strengths and weaknesses of the nuclear models used. In addition, I will discuss the problem of "quenching", i.e. of reduction of the matrix elements of weak axial current in complex nuclei, that potentially affects the neutrinoless double beta decay matrix element values signiffcantly
98. Particle Physics Seminar
"Evaluation of reactor neutrino flux: issues and uncertainties"
Presented by Professor Petr Vogel, Caltech
Thursday, March 30, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
Evaluation of the reactor antineutrino flux and spectrum is an essential ingredient of their application in the neutrino oscillation studies. Two anomalies, i.e. discrepancies between the observed and expected count rates, are widely discussed at the present time. The total rate is about 6% lower than the expectation at all distances > 10 m from the reactor. And there is a shoulder (often referred to as "bump") at neutrino energies 5-7 MeV, not predicted in the calculated spectrum. I review the ways the flux and spectrum is evaluated. I argue that far reaching conclusions based on these anomalies should await a thorough understanding of the uncertainties of the spectrum, and point out possible standard physics sources of the anomalies.
99. Condensed-Matter Physics & Materials Science Seminar
"Explore Mesoscopic Physics in Strongly Correlated Electron Materials with IR near-field microscopy and spectroscopy"
Presented by Mengkun Liu, Stony Brook University
Thursday, March 30, 2017, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: 'Cedomir Petrovic'
In strongly correlated electron materials, the delicate interplay between spin, charge, and lattice degrees of freedom often leads to extremely rich phase diagrams exhibiting intrinsic phase inhomogeneities. The key to understanding such complexities usually lies in the characterization and control of these materials at fundamental energy, time and length scales. I will use this opportunity to report the recent advances in the IR and THz near-field microscopy and spectroscopy, and explain how they can be used to probe electronic/structural phase transitions with unprecedented spatial and temporal resolutions. Specifically, with scanning near-field infrared microscopy we resolved the insulator to metal phase transitions in 3d (VO2), 4d (Ca2RuO4) and 4f (SmS) materials with ~10 nm resolution over a broad spectral range. The results set the stage for future spectroscopic investigations to access the fundamental properties of complex materials.
100. RIKEN Lunch Seminar
"The hadronic light-by-light contribution to muon g-2 from lattice QCD"
Presented by Luchang Jin, BNL
Thursday, March 30, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Enrico Rinaldi'
The current measurement of muonic g-2 disagrees with the theoretical calculation by about 3 standard deviations. Hadronic vacuum polarization (HVP) and hadronic light by light (HLbL) are the two types of processes that contribute most to the theoretical uncertainty. The current value for HLbL is still given by models. We report our latest lattice calculation of hadronic light-by-light contribution to muon g-2 using our recent developed moment method. The connected diagrams and the leading disconnected diagrams are included. The calculation is performed on a 48^3 × 96 lattice with physical pion mass and 5.5 fm box size. We expect sizable finite volume and finite lattice spacing corrections to the results of these calculations which will be estimated in calculations to be carried out over the next 1-2 years.
101. Particle Physics Seminar
"Is there evidence for cosmic acceleration?"
Presented by Subir Sarkar, Oxford University
Thursday, March 30, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: ''Xin Qian''
The 'standard' model of cosmology is founded on the basis that the expansion rate of the universe is accelerating at present – as was inferred from the Hubble disgram of Type la supernovae. There exists now a much bigger database of supernovae so we can perform rigorous statistical tests to check whether these 'standardisable candles' indeed indicate cosmic acceleration. Taking account of the empirical procedure by which corrections are made to their absolute magnitudes to allow for the varying shape of the light curve and extinction by dust, we find that the data are still consistent with a constant rate of expansion. The implications of this will be discussed.
102. Physics Colloquium
"Physics in the complex domain"
Presented by Carl Bender, Washington University
Tuesday, March 28, 2017, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: ''Robert Pisarski''
The theory of complex variables is extremely useful because it helps to explain the mathematical behavior of functions of a real variable. Complex variable theory also provides insight into the nature of physical theories. For example, it provides a simple and beautiful picture of quantization and it explains the underlying reason for the divergence of perturbation theory. By using complex-variable methods one can generalize conventional Hermitian quantum theories into the complex domain. The result is a new class of parity-time-symmetric (PT-symmetric) theories whose remarkable physical properties have been studied and verified in many recent laboratory experiments.
103. Condensed-Matter Physics & Materials Science Seminar
"Thermalization and light cones in a model with weak integrability breaking"
Presented by Stefan Groha, University of Oxford, United Kingdom
Tuesday, March 28, 2017, 11 am
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: '''Neil Robinson'''
We employ equation of motion techniques to study the non-equilibrium dynamics in a lattice model of weakly interacting spinless fermions. Our model provides a simple setting for analyzing the effects of weak integrability breaking perturbations on the time evolution after a quantum quench. We establish the accuracy of the method by comparing results at short and intermediate times to time-dependent density matrix renormalization group computations. For sufficiently weak integrability-breaking interactions we always observe prethermalization plateaux, where local observables relax to non-thermal values at intermediate time scales. At later times a crossover towards thermal behaviour sets in. We determine the associated time scale, which depends on the initial state, the band structure of the non-interacting theory, and the strength of the integrability breaking perturbation. Our method allows us to analyze in some detail the spreading of correlations and in particular the structure of the associated light cones in our model. We find that the interior and exterior of the light cone are separated by an intermediate region, the temporal width of which appears to scale with a universal power-law t 1/3.
104. Nuclear Physics Seminar
"Beam energy and system dependence of anisotropic flow measurements from STAR"
Presented by Niseem Magdy, Stony Brook University
Tuesday, March 28, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Jin Huang'
Recent STAR measurements of azimuthal anisotropy have focused on the use of two- and multi-particle correlations as probes for model constraints for the temperature dependence of the specific shear viscosity $\eta/s$ and the initial-state structure of the collision zone. We will discuss and summarize recent two- and multi-particle correlations measurements of $v_n$ $(n > 1)$ , dipolar flow $v^{even}_1$, and $\langle cos(n \varphi_{1} + m \varphi_{2} - (n+m) \varphi_{3}) \rangle$, as a function of centrality, transverse momentum ($p_T$), and pseudorapidity ($\eta$) for $Au+Au$ at ($\sqrt{s_{NN}} = 7 - 200$~GeV;{em BES-I}), $U+U$ at ($\sqrt{s_{NN}} = 193$ GeV) and $Cu+Au$ , $Cu+Cu$ ,$d+Au$ ,$p+Au$ at ($\sqrt{s_{NN}} = 200$ GeV).
105. Condensed-Matter Physics & Materials Science Seminar
"Resonant Inelastic X-ray Scattering and X-ray Emission Spectroscopy of Iron Pnictide Superconductors"
Presented by Jonathan Pelliciari, Paul Scherrer Institute, Switzerland
Monday, March 27, 2017, 10 am
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: 'Mark Dean'
I will describe Resonant Inelastic X-Ray Scattering (RIXS) experiments performed at the Swiss Light Source focusing on the detection of high-energy spin fluctuations on iron pnictides. I will show that RIXS has been successfully used to extract the spin excitation spectrum on NaFeAs, BaFe2As2, EuFe2As2 and SmFeAsO, parent compounds [1-3]. We investigated electron-doped NaFe1-xCoxAs observing the persistence of broad dispersive magnetic excitations in optimal and overdoped samples [1]. The energy of such modes is unaffected by doping and the magnetic weight per iron atom of magnons / paramagnons remains constant, demonstrating the impurity role of Co doping. The persistence of magnetic spectral weight is also caught by theoretical calculations. In the second part of the talk, I will present a combined Fe-L3 RIXS and Fe-Kβ X-rays emission spectroscopy (XES) study of isovalently doped BaFe2(As1-xPx)2 spanning a large portion of the phase diagram. RIXS measurements find the persistence of broad dispersive magnetic excitations for all doping levels. Remarkably, the energy of such modes is strongly hardened by doping differently from the cases of electron- and hole-doped BaFe2As2 [5]. On the other hand, XES experiments show a gradual quenching of the local magnetic moment, which is intriguing if compared to the behavior of spin correlations. We link the unconventional evolution of magnetism to the shift from 2- to 3-dimensional electronic structure of the system, hand in hand with the warping of the Fermi surface. Combined together these findings help to shed light on the real degree of electronic correlations in Fe pnictides. References [1] J. Pelliciari et al., Phys. Rev. B, 93, 134515 (2016); [2] J. Pelliciari et al., Appl. Phys. Lett. 109, 122601 (2016); [3] J. Pelliciari et al., "Local and collective magnetism of EuFe2As2" accepted in Phys. Rev. B (2017); [4] K. J. Zhou et al, Nat. Comm., 4, 1470 (2013)
106. Nuclear Theory/RIKEN Seminar
"A solitonic approach to neutron stars: The (BPS) Skyrme model"
Presented by Carlos Naya, Durham
Friday, March 24, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
The Skyrme model is a low energy effective field theory of strong interactions where nuclei and baryons appear as collective excitations of pionic degrees of freedom. Proposed by Tony Skyrme in the sixties, his ideas received further support when it was discovered that in the limit of the large number of colours of QCD, an effective theory of mesons arises. In the last years, there has been a revival of Skyrme's ideas and new related models, some of them with BPS bounds (topological lower energy bounds), have been proposed. It is the aim of this talk to focus on the one known as BPS Skyrme model. After a brief introduction to this BPS limit we study its application to neutron stars where we will find that high maximal masses are supported. In addition, the BPS Skyrme model allow us to perform both mean-field and exact calculations and a comparison between both approaches will be presented.
107. Condensed-Matter Physics & Materials Science Seminar
"Shining a light on high-Tc superconductivity"
Presented by Peter Johnson, BNL
Friday, March 24, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: '''Igor Zaliznyak'''
TBD
108. Particle Physics Seminar
"Neutrino Interactions with Nuclei and Long-Baseline Experiments"
Presented by Professor Ulrich Mosel, Giessen University
Friday, March 24, 2017, 10 am
Small Seminar Room, Bldg. 510
Hosted by: ''Xin Qian''
The extraction of neutrino mixing parameters and the CP-violating phase requires knowledge of the neutrino energy. This energy must be reconstructed from the final state of a neutrino-nucleus reaction since all long-baseline experiments use nuclear targets. This reconstruction requires detailed knowledge of the neutrino reactions with bound nucleons and of the final state interactions of hadrons with the nuclear environment. Quantum-kinetic transport theory can be used to build an event generator for this reconstruction that takes basic nuclear properties, such as binding, into account. Some examples are discussed that show the effects of nuclear interactions on observables in long-baseline experiments.
109. Condensed-Matter Physics & Materials Science Seminar
"Nematic quantum paramagnet and possible application to FeSe"
Presented by Fa Wang, International Center for Quantum Materials Peking University, China
Thursday, March 23, 2017, 11 am
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: ''Weiguo Yin''
The nematic phases in iron pnictides are in close proximity to the stripe antiferromagnetic order, suggesting that magnetism is the driving force for the spontaneous 4-fold crystal rotation symmetry breaking. In contrast, bulk FeSe shows a nematic phase below 90K at ambient pressure, but has no magnetic long range order down to very low temperature. This prompts suggestions that the nematicity in FeSe is driven by some other mechanism. We argue that magnetic correlation can still drive nematic order in the absence of magnetic long-range order. By field theoretical considerations and exact diagonalization results on finite size lattices, we conclude that the paramagnetic phase in frustrated spin-1 J_1-J_2 model on square lattice is likely a "nematic quantum paramagnet", which breaks only the crystal 4-fold rotation symmetry. The prototype wavefunctions of such quantum ground states are horizontal(vertical) aligned spin-1 AKLT chains. We suggest that the local spins in FeSe may form this phase due to strong frustration. One unique consequence of this proposal is that the nematic paramagnetic phase will be close to both stripe and Neel antiferromagnetic order, and will thus host low but finite energy spin fluctuations at both ordering wavevectors. Reference: Fa Wang, S. A. Kivelson, and Dung-Hai Lee, Nat. Phys. 11, 959 (2015)
110. Particle Physics Seminar
"Heavy bosons: a probe into the unknown"
Presented by Viviana Cavaliere, University of Illinois Champaign/Urbana
Wednesday, March 22, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: ''Michael Begel''
The large amount of high-energy proton-proton collision data at the LHC provides an unprecedented opportunity to search for new physics beyond the Standard Model at the TeV scale. The 2012 discovery of a 125 GeV Higgs boson opened a new door to understanding the universe, providing an exciting new tool to use in these searches, given it is now produced about once per second at the current collision rate. The talk will review recent ATLAS searches for physics beyond the Standard Model, focusing on the central role of processes with heavy bosons, including the Higgs, and the corresponding new possible signatures that range from spectacular new resonances to subtle changes in kinematic distributions.
111. Nuclear Theory/RIKEN Seminar
"Universal Transverse Momentum Dependent Fragmentation"
Presented by Duff Neill, LANL
Friday, March 17, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
Fragmentation is the earliest and perhaps most interesting QCD jet observable, since it directly deals with the parton-hadron duality at the end of the QCD cascade. The most basic fragmentation observables all enjoy the property of being universal, in the sense that a sufficiently energetic parton that initiates the cascade factorizes from the rest of the event, so that the underlying soft structure of the event to a good approximation does not change the fragmentation spectrum. With the luminosities and resolution of modern detectors, we can begin to study the fragmentation process in three dimensions: both the energy spectrum and the transverse fluctuations to the collinear direction of initiating hard parton. However, when one wants to study the transverse fluctuations, one becomes very sensitive to the underlying jet definition, in particular, how the collinear direction is defined. Intuitive definitions of the jet direction, like the total momentum of the jet constituents, are inherently sensitive to soft processes, and can spoil the universality of the spectrum. I will discuss how a simple change in the jet definition removes this soft sensitivity, and allows one to study the intrinsic three dimensional structure of collinear splittings, which should be process independent.
112. RIKEN Lunch Seminar
"TBA"
Thursday, March 16, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Hiromichi Nishimura'
113. Particle Physics Seminar
"Search for physics beyond the SM using multijet events with the ATLAS detector at the LHC"
Presented by Haichen Wang, LBL
Thursday, March 16, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: ''Michael Begel''
Search for physics beyond the Standard Model (SM) has been one of the most important goals of the physics program at the Large Hadron Collider (LHC).Among all the final states, the multijet final state has long been considered as a challenging one for the search of physics beyond the SM due to its large background. Though, exciting new physics phenomena, such as the production of black hole as well as massive supersymmetric (SUSY) particles, may well result in signals in multijet final state. I present searches for physics beyond the SM using multijet events from 13 TeV collision data taken in 2015 and the first half of 2016 by the ATLAS experiment at the LHC. I focus on a search for the production of black hole and a search for massive supersymmetric particles decaying to many jets via R-Parity Violating (RPV) couplings. The two examples represent searches targeting physics beyond the SM at different mass scales, and therefore different analysis strategies are employed. These searches have greatly improved the sensitivity of the LHC to the black hole production and RPV SUSY scenarios, and they are complementary to searches using events of leptons, photons and missing transverse energy.
114. Nuclear Physics Seminar
"The sPHENIX Calorimeters: a proto-type story"
Presented by Megan Connors, Georgia State University and RBRC
Wednesday, March 15, 2017, 3:30 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Jin Huang''
sPHENIX, scheduled to start taking data in 2022 at RHIC, is a detector designed to probe the inner workings of the quark gluon plasma by measuring jets and their substructure, heavy flavor tagged jets and quarkonia. The design includes tracking systems, a solenoid magnet and calorimeter system. The calorimeter system, designed to measure the energy of jets, is comprised of an electromagnetic calorimeter, an inner hadronic calorimeter and and outer hadronic calorimeter. Prototypes of these detectors were built and tested in 2016. The results of the test beam show that the performance is well within the requirements set by the sPHENIX program. In addition, the results validate the GEANT4 simulation studies. The design of the sPHENIX calorimeter system, the test beam results from the calorimeter prototypes and additional studies will be presented
115. HET/RIKEN Seminar
"Hunting for New Leptonic Interactions at Colliders"
Presented by Brian Shuve, SLAC
Wednesday, March 15, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Pier Paolo Giardino''
116. Nuclear Theory Seminar
"Nuclear Matter EoS and thermodynamic Properties of Skyrme models"
Presented by Mareike Haberichter, Amherst
Friday, March 10, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
The Skyrme model is a candidate to describe the low energy regime of QCD where baryons and nuclei are topological excitations in a low-energy effective field theory of pions. The Skyrme model and its BPS variant (Skyrme model with a lower topological energy bound which is saturated) have been applied to the description of nuclei with notable recent success, e.g. quantitative description of Carbon-12 (including the Holye state and its rotational band) and of the low-lying energy spectrum of Oxygen-16. In this talk, we test Skyrme theories as models for nuclear matter at high densities and explore the thermodynamical properties of skyrmionic matter at zero temperature. We compute analytically the mean-field equation of state in the high and medium pressure regimes by applying topological bounds on compact domains. We identify which term in a generalised Skyrme model is responsible for which part in the equation of state and compare our findings with the corresponding results in the Walecka model. We find that the BPS submodel plays the dominant role at large densities. The BPS Skyrme model even allows us to derive thermodynamical variables and densities directly from the theory without having to perform a mean-field limit. This distinguishes the BPS Skyrme model from other models of nuclear matter where usually a mean-field limit has to be performed. Note that this is the first of two talks on Skyrme models and their predictions for nuclear matter at high densities. The second part on the description of neutron stars as Skyrme solitons will be given by Carlos Naya (Durham) on March, 24th at BNL.
117. Particle Physics Seminar
"WW measurements at CMS and perspectives for the HL-LHC"
Presented by Rafael Coelho Lopes de Sa, FNAL
Thursday, March 9, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Michael Begel'
We will review recent diboson measurements and searches in the WW final state performed with the CMS detector. We will discuss the perspectives for some of these measurements with the full HL-LHC dataset. We will briefly describe some of the upgrades being designed for the CMS Silicon Tracker in order to operate in the high pileup environment of the HL-LHC while maintaining excellent performance for the final states discussed in this talk.
118. RIKEN Lunch Seminar
"Finite-Temperature Perturbative QCD confronts Lattice"
Presented by Thorben Graf, University of Frankfurt
Thursday, March 9, 2017, 12:30 pm
Building 510, Room 1-224
Hosted by: '''Heikki Mantysaari'''
Since decades expressions for the thermodynamic potential were calculated perturbatively at finite temperature (and density) and pushed to higher orders. I review the current status of these efforts including resummation techniques and compare them to results of lattice Monte Carlo simulations and address unanswered questions. Finally, I present results for several thermodynamic quantities within the next-to-leading order calculation of the thermodynamic potential at finite T and \mu including non-vanishing quark masses.
119. Condensed-Matter Physics & Materials Science Seminar
"Transport and signatures of Mottness versus Hundness in strongly correlated metals"
Presented by Xiaoyu Deng, Rutgers
Thursday, March 9, 2017, 11 am
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: ''Gabi Kotliar''
In this seminar I will focus two fundamental aspects of strongly correlated metals: the transport properties and the origin of correlation. Recent advances enables us to study quantitatively various properties of two archetypal correlated oxides, vanadium oxides and ruthenates, using the LDA+DMFT method. Both are strongly correlation, these two materials are quite different in their origins of correlation: V2O3 is proximate to a Mott state while Sr2RuO4 is not. Thus V2O3 is regarded as a prototype Mott system, while recent studies emphasize that Sr2RuO4 belongs to new category termed "Hund's metal" in which Hund's coupling is responsible for the correlations. We carried out a systematical theoretical study on the transport properties of V2O3 and ruthenates family. Our computed resistivity and optical conductivity are in very good agreement with experimental measurements, which clearly demonstrates that the strong correlation dominates the transport of this material , despite their origin of correlation. We demonstrated that "resilient quasiparticles" dominates the transport. Furthermore by expressing the resistivity in terms of an effective plasma frequency and an effective scattering rate, we uncover the so-called "hidden Fermi liquid" behavior. We identified signatures of Mottness and Hundness by a comparative study of V2O3 and Sr2RuO4. In V2O3 the low temperature coherent resonance emerges from the pseudogap regime appearing at high temperature between incoherent peaks, while in Sr2RuO4, it emerges from a single incoherent peak with large finite value at the Fermi level.. We show that these two contrasting scenarios features interesting behaviors in the local properties of correlated atoms including charge fluctuations, spin and orbit susceptibility and entropy. The findings shed new lights on the understanding of strongly correlated metals.
120. Particle Physics Seminar
"Electroweak Physics at ATLAS"
Presented by Jake Searcy, Michigan
Wednesday, March 8, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Michael Begel'
Electroweak symmetry breaking is a central pillar of the standard model, and experimentally one of the least understood. Many physics scenarios predict modifications to this mechanism resulting in new particles or interactions. This talk will summarize our knowledge of the electroweak sector with a particular focus on the interactions between W-bosons.
121. Environmental & Climate Sciences Department Seminar
"Sub 2 nm Particle Characterization in Systems with Aerosol Formation and Growth"
Presented by Yang Wang, Washington University
Wednesday, March 8, 2017, 10 am
Conference Room Bldg 815E
Hosted by: 'Jian Wang'
Aerosol science and technology enable continual advances in material synthesis and atmospheric pollutant control. Among these advances, one important frontier is characterizing the initial stages of particle formation by real time measurement of particles below 2 nm in size. Sub 2 nm particles play important roles by acting as seeds for particle growth, ultimately determining the final properties of the generated particles. Tailoring nanoparticle properties requires a thorough understanding and precise control of the particle formation processes, which in turn requires characterizing nanoparticle formation from the initial stages. This work pursued two approaches in investigating incipient particle characterization in systems with aerosol formation and growth: (1) using a high-resolution differential mobility analyzer (DMA) to measure the size distributions of sub 2 nm particles generated from high-temperature aerosol reactors, and (2) analyzing the physical and chemical pathways of aerosol formation during combustion. Part. 1. Particle size distributions reveal important information about particle formation dynamics. DMAs are widely utilized to measure particle size distributions. However, our knowledge of the initial stages of particle formation is incomplete, due to the Brownian broadening effects in conventional DMAs. The first part of this presentation discusses the applicability of high-resolution DMAs in characterizing sub 2 nm particles generated from high-temperature aerosol reactors, including a flame aerosol reactor (FLAR) and a furnace aerosol reactor (FUAR). Comparison against a conventional DMA (Nano DMA, Model 3085, TSI Inc.) demonstrated that the increased sheath flow rates and shortened residence time indeed greatly suppressed the diffusion broadening effect in a high-resolution DMA (half mini type). The incipient particle size distributions were discrete, suggesting the formation of stable clusters that may be intermediate phases betw
122. Physics Colloquium
"Snapping pictures of the proton with heavy ions"
Presented by Bjoern Schenke, BNL
Tuesday, March 7, 2017, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: ''Robert Pisarski''
I will present an overview of recent theoretical developments related to the science program at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory and the Large Hadron Collider at CERN. Beginning from heavy ion collisions and the creation of the quark gluon plasma, the most perfect and hottest fluid every created on earth, I will proceed to discuss smaller collision systems, like proton+lead collisions. The experimental data from these show strikingly similar features to heavy ion collisions and I will discuss their possible origins. If the physics in these small systems is also dominated by the fluid dynamic behavior of the created matter, experimental measurements combined with theoretical models give us unprecedented access to the fluctuating shape of the proton.
123. NSLS-II Engineering Seminar Series
"High-Resolution Monochromator Development for Nuclear Resonant Scattering"
Presented by Thomas Toellner, X-Ray Science Division,
Tuesday, March 7, 2017, 2 pm
John Dunn Seminar Room, Bldg. 463
Hosted by: ''Sushil Sharma and Mary Carlucci-Dayton''
High-resolution monochromators (HRMs) are key components at nuclear resonant scattering beamlines, and their development at the APS has been ongoing for decades. They are used to resolve the frequency spectrum of isotope-specific atomic dynamics using nuclear resonant vibrational spectroscopy and to reduce the enormous electronic charge scattering that accompanies nuclear excitation using synchrotron radiation. The latter allowing the measurement of hyperfine fields using synchrotron Moessbauer spectroscopy. The narrow line-widths (neV) associated with nuclear resonances also offer an excellent diagnostic tool for the characterization of HRMs, and have greatly facilitated their development. HRMs with ultra-high energy-resolution exposed the need for greater energy-alignment stability and prompted the development of cryo-stabilization. A recent prototype sub-meV-bandwidth monochromator for hard X-rays that implements cryo-stabilization has been built that displays a 100-fold improvement in energy-alignment stability over other designs. This unprecedented level of control allows one to observe the intrinsic factors that limit the energy resolution obtainable with silicon. I will present the principle design aspects of this prototype along with its performance, and discuss what has been learned.
124. Nuclear Physics Seminar
"Collectivity in small collision systems, what is it?"
Presented by Jiangyong Jia, BNL and Stony Brook University
Tuesday, March 7, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Jin Huang'
In recent years, there been rapid progresses in our understanding of the long-range ridge in small collision system at RHIC and LHC. I will discuss the nature of collectivity (flow) driving the ridge, as well as the dominating non-collective (or non-flow) background that complicates the extraction of the ridge. I shows that the standard multi-particle cumulant method, often used to defined collectivity in heavy ion collisions, is overwhelmed by non-collective background in pp and low multiplicity pPb collisions. This problem is resolved with an alternative method based on two or more subevents separated in pseudorapidity (η), and therefore offers a robust data-driven definition of collectivity based on the existence of long-range azimuthal correlations between multiple distinct η ranges. With this new cumulant method, we are able to probe reliably the event-by-event fluctuation of collectivity in small collision systems.
125. NSLS-II Friday Lunchtime Seminar Series
"Elemental Concentration and Size Apportionment of Combustion Particles from Wood-fired Appliances" and "Creating Methods for Material Design and Synthesis for Microporous and Mesoporous Materials"
Presented by Monica Gray-Georges and Nicholas Brunelli, Lincoln University of Pennsylvania and Ohio State University
Friday, March 3, 2017, 12 pm
NSLS-II Bldg 743 (LOB 3), room 156
Hosted by: ''Ben Ocko and Shirish Chodankar''
126. Condensed-Matter Physics & Materials Science Seminar
"Ab Initio electronic structure of solids: correlation effects beyond the GW method"
Presented by Andrei Kutepov, Rutgers University
Thursday, March 2, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: ''''Gabi Kotliar''''
TBA
127. RIKEN Lunch Seminar
"Generalized Nambu-Goldstone theorem"
Presented by Yoshimasa Hidaka, RIKEN
Thursday, March 2, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Hiromichi Nishimura''
Symmetry and its spontaneous breaking are of basic importance for understanding the low energy physics in many-body systems. When a continuum symmetry is spontaneously broken, there exist a zero mode called Nambu-Goldstone (NG) mode, which is well developed in Lorentz invariant systems. In contrast, in non-Lorentz invariant systems, the NG theorem has not been well developed. In this talk, we discuss the recent progress in generalization of NG theorem in non-relativistic systems, open systems, and systems with higher form symmetries.
128. Particle Physics Semiar SB/BNL Joint Cosmo Seminar
"TBA"
Presented by Will Farr, Birmingham
Wednesday, March 1, 2017, 1:30 pm
Stony Brook University
129. Physics Colloquium
"The Experimental Challenge of 21 cm Cosmology"
Presented by Miguel Morales, University of Washington
Tuesday, February 28, 2017, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: ''Andrei Nomerotski''
130. RIKEN Lunch Seminar
"The Kibble-Zurek scaling for the Entanglement Entropy on the scalar field in 1+1 dimension"
Presented by Akio Tomiya, CCNU
Monday, February 27, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Hiromichi Nishimura'
The entanglement entropy is a candidate of an entropy in Non-equilibrium physics and recently, relaxation or thermalization is studied through the entanglement entropy with quamtum quenching, which is sudden change of parameter(s) in the Hamiltonian of the system. Global quantum quench with a finite rate which crosses critical points is known to lead to universal scaling of correlation functions as functions of the quench rate. We explore scaling properties of the entanglement entropy of a subsystem of a scaler field on the lattice, harmonic chain, during a mass quench which asymptotes to finite constant values at early and late times and for which the dynamics is exactly solvable. Both for fast and slow quenches we find that the entanglement entropy has a constant term plus a term proportional to the subsystem size. For slow quenches, the constant piece is consistent with Kibble- Zurek predictions. Furthermore, the quench rate dependence of the extensive piece enters solely through the instantaneous correlation length at the Kibble-Zurek time, suggesting a new scaling hypothesis similar to that for correlation functions. This talk is based on arXiv:1702.04359.
131. Nuclear Theory Seminar
"A Complete Diagrammatic Implementation of the Kinoshita-Lee-Nauenberg Theorem at Next-to-Leading Order"
Presented by Will Horowitz, University of Cape Town
Friday, February 24, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
We show for the first time in over 50 years how to correctly apply the Kinoshita-Lee-Nauenberg theorem diagrammatically in a next-to-leading order scattering process. We improve on previous works by including all initial and final state soft radiative processes, including absorption and an infinite sum of partially disconnected amplitudes. Crucially, we exploit the Monotone Convergence Theorem to prove that our delicate rearrangement of this formally divergent series is correct. This rearrangement yields a factorization of the infinite contribution from the initial state soft photons that then cancels in the physically observable cross section. We derive the first complete next-to-leading order, high-energy Rutherford elastic scattering cross section in the MSbar renormalization scheme as an explicit example of our procedure.
132. RIKEN Lunch Seminar
"Path-integral formula for local thermal equilibrium"
Presented by Masaru Hongo, RIKEN
Thursday, February 23, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Hiromichi Nishimura''
Relativistic hydrodynamics is formulated based on the assumption that systems are almost in local thermal equilibrium. However, a quantum field theoretical way to handle such a locally thermalized system has not been clearly clarified. In this study, we develop a complete path-integral formulation of relativistic quantum fields in local thermal equilibrium, which brings about the emergence of thermally induced curved spacetime. The obtained path-integral formula for local thermal equilibrium enables us to derive nondissipative part of hydrodynamic constitutive relations based on symmetry arguments. As one application, we discuss a field theoretical derivation of anomalous hydrodynamics which captures the chiral magnetic/vortical effects.
133. HET/RIKEN Seminar
"Few-body systems in QCD"
Presented by Raul A. Briceno, JLAB
Wednesday, February 22, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Mattia Bruno'
134. Nuclear Theory/RIKEN Seminar
"High energy QCD at NLO"
Presented by Michael Lublinsky, Ben-Gurion University
Friday, February 17, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Chun Shen'
135. RIKEN Lunch Seminar
"The search for gluon saturation in pA collisions and at the EIC"
Presented by Bowen Xiao, Central China Normal University
Thursday, February 16, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Heikki Mantysaari'
In this talk, I plan to discuss the recent theoretical progress towards the exploration of the gluon saturation phenomenon in pA collisions and at the future EIC. Two important pillars of this exploration are the single inclusive forward hadron productions and forward dijet correlations, which have both been computed up to one-loop order within the small-x factorization formalism. Complementary measurements in pA collisions and at the EIC can help us measure small-x gluon distributions and test the generalized small-x factorization. In addition, DIS diffractive dijet process is another interesting process which is sensitive to the dipole Wigner gluon distributions. This process can provide us 3D tomographic images of low-x gluons inside high energy protons and nuclei.
136. HET/RIKEN Seminar
"Extracting scattering observables and resonance properties from lattice QCD"
Presented by Maxwell T. Hansen, Helmholtz Institute Mainz
Wednesday, February 15, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Mattia Bruno'
137. Particle Physics Seminar - SB/BNL Joint Cosmo Seminar
"TBA"
Wednesday, February 15, 2017, 1:30 pm
Stony Brook University
138. Physics Colloquium
"Thermalization and hydrodynamization in heavy-ion collisions at high energies"
Presented by Aleksi Kurkela, CERN and Univ. of Stavenger
Tuesday, February 14, 2017, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: ''Robert Pisarski''
Describing heavy-ion collisions as hydrodynamical explosions of liquid of quarks and gluons has been a tremendous phenomenological success. A major uncertainty in such modeling arises from what happens during the first 1fm/c of the evolution during which the system is far from local thermal equilibrium. I will describe how the postcollision debris start behaving hydrodynamically, and how the phenomenological modeling of the prehydrodynamical evolution can be improved.
139. Condensed-Matter Physics & Materials Science Seminar
"Thermalization and chaos in quantum systems"
Presented by Sriram Ganeshan, Stony Brook University
Tuesday, February 14, 2017, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: '''Robert Konik'''
Thermalization, a common phenomenon in various physical settings, can naturally fail in certain isolated disordered quantum systems, challenging basic tenets of quantum statistical mechanics. Many body localization (MBL) is a canonical example of such an intriguing scenario and, therefore, attracted tremendous attention from condensed matter, statistical physics, and atomic physics communities. Considerable effort has recently gone into establishing the existence of the MBL phase, and the nature of dynamical phase transition from MBL to the thermal phase. However, understanding instabilities to the MBL phase that may lead to the complete or partial restoration of thermalization is still an open question. In this talk, I would focus on two such instabilities to the MBL phase coming from single particle mobility edge and the presence of extensive degeneracy in the many body spectrum. The goal is to identify the most robust form of MBL (in the presence of instabilities) to gain insight into the mechanisms of quantum thermalization.
140. Environmental & Climate Sciences Department Seminar
"The Impact of Organic Aerosol Volatility on Aerosol Microphysics for Global Climate Modeling Applications"
Presented by Yuchao 'Chloe' Gao, NASA Goddard Institute for Space Studies, China
Thursday, February 9, 2017, 11 am
Conference Room Bldg 815E
Hosted by: 'Robert McGraw'
A newly developed box model, MATRIX-VBS [Gao et al., 2017], includes the volatility-basis set (VBS) framework in an aerosol microphysical scheme MATRIX (Multiconfiguration Aerosol TRacker of mIXing state) [Bauer et al., 2008], which is a module within GISS ModelE that resolves aerosol mass and number concentrations and aerosol mixing state. By including the gas-particle partitioning and chemical aging of semi-volatile organic aerosol in MATRIX, we were able to examine its effects on the growth, composition and mixing state of particles. MATRIX-VBS is unique and advances the representation of organic aerosols in Earth system models by greatly improving the traditional and very simplistic treatment of organic aerosols as non-volatile and with a fixed size distribution. Idealized cases representing Beijing, Mexico City, a Finnish and a Southeast U.S. forest were simulated, and we investigated the evolution of mass concentrations and volatility distributions for organic species across the gas and particle phases, as well as their mixing state among aerosol populations. To test and simplify the model, a Monte-Carlo analysis is performed to pin point which processes affect organics the most under varied chemical and meteorological conditions. Since the model's parameterizations have the ability to capture a very wide range of conditions, all possible scenarios on Earth across the whole parameter space, including temperature, humidity, location, emissions and oxidant levels, are examined. These simulations provide information on which parameters play a critical role in the aerosol distribution and evolution in the atmosphere and which do not, and that will facilitate the simplification of the box model, an important step in its implementation in the global model GISS ModelE as a module.
141. Particle Physics Seminar - SB/BNL Joint Cosmo Seminar
"TBA"
Presented by Tim Eifler, JPL/Caltech
Wednesday, February 8, 2017, 1:30 pm
Stony Brook University
142. Particle Physics Seminar
"Di-Higgs at the LHC: Current Status and Future Prospects"
Presented by John Alison, University of Chicago
Thursday, February 2, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Michael Begel'
I will discuss motivations for searching for di-Higgs production at the LHC. Recent results and projected sensitivities will be presented with particular emphasis on the dominant hh->4b channel
143. Particle Physics Seminar - SB/BNL Joint Cosmo Seminar
"TBA"
Presented by Elisabeth Krause, SLAC
Wednesday, February 1, 2017, 1:30 pm
Stony Brook University
144. Nuclear Theory/RIKEN Seminar
"What shines brighter, Glasma or Quark-Gluon Plasma?"
Presented by Naoto Tanji, University of Heidelberg
Friday, January 27, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
Recent classical-statistical numerical simulations have established the "bottom-up" thermalization scenario of Baier et al. as the correct weak coupling effective theory for thermalization in ultrarelativistic heavy-ion collisions. I will talk on a parametric study of photon production in the various stages of this bottom-up framework to ascertain the relative contribution of the off-equilibrium "Glasma" relative to that of a thermalized Quark-Gluon Plasma. Taking into account the constraints imposed by the measured charged hadron multiplicities at RHIC and the LHC, we find that Glasma contributions are important especially for large values of the saturation scale at both energies. Furthermore, I will report on first kinetic simulations of photon production in the expanding Glasma that will quantify our estimates.
145. Particle Physics Seminar
"New Models of Baryogenesis"
Presented by Dr. David McKeen, University of Pittsburgh
Thursday, January 26, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Hooman Davoudiasl''
I will describe a new mechanism for creating the matter-antimatter asymmetry of the Universe at low temperatures, i.e. below the QCD confinement temperature, involving the CP-violating oscillation of fermions made of strongly interacting particles. I will also make connections to neutron-antineutron oscillations, clearing up issues that exist in the literature. Novel experimental tests will be discussed.
146. Condensed-Matter Physics & Materials Science Seminar
"Anion-based approaches to engineering functionality in perovskite oxide heterostructures"
Presented by Steve May, Drexel University
Thursday, January 26, 2017, 1:30 pm
ISB Bldg. 734, Conf. Room 201 (upstairs)
Hosted by: ''Mark Dean''
Scientific interest in ABO3 perovskite oxides remains intense due to the wide range of physical behavior present in these materials. The ability to control the position, occupation, and composition of the anion site has recently emerged as a new route to tune properties in epitaxial perovskites. This talk will focus on recent and ongoing efforts aimed at developing anion-based approaches to tailor electronic, optical and magnetic properties in oxide heterostructures. First, I will discuss how the position of the oxygen anions can be controlled to stabilize non-bulk-like bond angles and lengths, thereby modifying electronic and magnetic behavior in manganite films and superlattices. In the second half of the talk, I will describe efforts focused on controlling the occupation and composition of the anion site, including reversible oxidation/reduction in thin La1/3Sr2/3FeO3-? films and topotactic fluorination reactions to realize oxyfluoride films
147. RIKEN Lunch Seminar
"From small to moderate-x: beyond the eikonal approximation"
Presented by Andrey Tarasov, BNL
Thursday, January 26, 2017, 12:30 pm
Building 510, Room 1-224
Hosted by: '''Hiromichi Nishimura'''
In recent years significant progress has been made in our understanding of the small-x physics beyond the eikonal approximation. Rigorous analysis of the dependence on the transverse momentum helps us better understand not only physics of the Regge limit, but to connect it to the kinematic limit of the moderate-x as well. I'll describe the technique we used in calculation of TMD evolution observed in the Drell-Yan process and present some recent results.
"Engineering Studies Related to Nuclear Molecular Imaging"
Presented by Dr. Dohyun Kim, Weill Cornell Medicine
Tuesday, January 24, 2017, 4 pm
Bldg 911B, Large Conf. Rm., Rm. A202
One of the major uses of radioisotopes is for nuclear molecular imaging using a variety of radiotracers. It is a multidisciplinary science that includes physics, chemistry, biology, computer science, mathematics and medicine with the goal of improving human life. These radiotracers can be used in a PET scanner (or other types of scanners) to generate a three dimensional image of the inside of the human body. PET scanners are used mainly for brain research and cancer detection. The goal of positron emission tomography (PET) is to generate in-vivo images from patients with a disease or abnormal condition. PET scanners detect the 511 keV annihilation gamma rays that are produced when a positron from a nuclear decay interacts with an electron. The gamma rays are given off at nearly 180° from each other and can be detected as originating along a straight line if they arrive at the detectors within a given time interval known as the coincidence window. I will describe the development of a very novel PET scanner with very high resolution using CZT solid state detectors. A novel feature of this system design is that the CZT detectors are rotated 90 degrees from their conventional orientation to use the C/A ratio such that the depth direction is oriented tangentially to the circular FOV of the tomograph. Thus the expected ~0.25 ? depth resolution of the detectors can be used to provide ultra-high resolution in the transaxial plane. The CdZnTe detector PET scanner we developed has a 600 micron FWHM image resolution and an excellent energy resolution of < 2 % FWHM. I will also discuss the development and fabrication of gas phase 11CO2 to 11CO, H11CN, 11CH3I and 11CH3OTf auto synthesis system. These systems are used to generate the radiotracers used with PET. The design and fabrication involve understanding the chemistry, utilizing the physics of flow and transport and engineering a final solution that incorporates these effects.
149. Condensed-Matter Physics & Materials Science Seminar
"Ultrafast Dynamical Phenomena in Nanostructural Materials by 4D Electron Microscopy"
Presented by Xuewen Fu, California Institute of Technology
Tuesday, January 24, 2017, 2 pm
Building 480, Conference Room
Hosted by: ''Yimei Zhu''
150. Condensed-Matter Physics & Materials Science Seminar
"Creation and Control of Low Dimensional Electron System in Transition Metal Oxides"
Presented by Milan Radovic, Paul Scherer Institut, Switzerland
Monday, January 23, 2017, 11 am
Building 734, conference room 201
Hosted by: '''Cedomir Petrovic'''
Transition Metal Oxides (TMOs) exhibit unique and multifunctional electronic properties (such as high-temperature superconductivity, colossal magnetoresistance, metal-insulator transitions, etc.) directly related to the spin and orbital degrees of freedom of the transition metal d-states. Furthermore, their iso-structural nature permits realization of heterostructures where novel unexpected electronic properties take place. Engineering transition metal oxide surfaces and interfaces carries the potential for achieving new physical properties that radically differ from those of the constituent bulk materials. This is the case of oxide-lowDEGs, which recently showed extraordinary occurrences, including interfacial superconductivity, magnetism, large tuneable spin-orbit coupling and indications of topological states. In my talk, I will present recent spin resolved Angle Resolved Photoemission Spectroscopy (ARPES) measurements of the low dimensional electron gas at SrTiO3 [1, 2, 3], TiO2-anatase and Sr1-xBaxTiO3 showing that these materials have capability for the realization of TMO based electronic device. References: [1] N. C. Plumb, M. Salluzzo, E. Razzoli, M. Månsson, M. Falub, J. Krempasky, C. E. Matt, J. Chang, J. Minár, J. Braun, H. Ebert, B. Delley, K.-J. Zhou, C. Monney, T. Schmitt, M. Shi, J. Mesot1, C. Quitmann, L. Patthey, M. Radovic, Phys. Rev. Lett. 113, 086801 (2014). [2] A. F. Santander-Syro, F. Fortuna, C. Bareille, T. C. Rodel, G. Landolt, N. C. Plumb, J. H. Dil, and M. Radovic, Nature Materials, 13, 1085–1090 doi:10.1038/nmat4107 (2014). [3] Z. Wang, S. McKeown Walker, A. Tamai, Z. Ristic, F.Y. Bruno, A. de la Torre, S. Ricco, N.C. Plumb, M. Shi, P. Hlawenka, J. Sanchez-Barriga, A. Varykhalov, T.K. Kim, M. Hoesch, P.D.C. King, W. Meevasana, U. Diebold, J. Mesot, M. Radovic, and F. Baumberger, Nature Materials 15, 835–839 (2016) doi:10.1038/nmat4623 (2016).
151. Nuclear Theory Seminar
"Helicity Evolution at Small x and the Proton Spin"
Presented by Yuri Kovchegov, Ohio State University
Friday, January 20, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
We construct small-x evolution equations which can be used to calculate quark and anti-quark helicity TMDs and PDFs, along with the g_1 structure function. These evolution equations resum powers of alpha_s ln^2 (1/x) in the polarization-dependent evolution along with the powers of alpha_s ln (1/x) in the unpolarized evolution which includes saturation effects. The equations are written in an operator form in terms of polarization-dependent Wilson line-like operators. While the equations do not close in general, they become closed and self-contained systems of non-linear equations in the large-N_c and large-N_c & N_f limits. After solving the large-N_c equations numerically we obtain the following small-x asymptotics for the flavor-singlet g_1 structure function along with quarks helicity PDFs and TMDs (in absence of saturation effects): g_1^S (x, Q^2) ~ \Delta q^S (x, Q^2) ~ g_{1L}^S (x, k_T^2) ~ ( 1/x )^{alpha_h} \approx t( 1/x )^{2.31 \sqrt{\alpha_s N_c/(2pi}} This result is valid for all flavors. We also give an estimate of how much of the proton's spin may reside at small x and what impact this has on the so-called spin crisis.'' This work would help one better understand longitudinal polarization data to be obtained at the proposed Electron-Ion Collider (EIC).
152. Center for Functional Nanomaterials Seminar
"Amyloid Self-Assembly and Sequence-Dependent Interactions with Plasmonic Nanoparticles"
Presented by Shih-Ting (Christine) Wang, Imperial College London, United Kingdom
Thursday, January 19, 2017, 2 pm
CFN, Bldg 735, Conference Room A, 1st Floor
Hosted by: ''Oleg Gang''
Nanoparticles (NPs) have been used to inhibit or modulate the peptide fibrillation as a potential therapeutic strategy and to understand the molecular mechanisms of amyloid diseases. Particularly, gold nanoparticles (AuNPs) have been widely used to study peptide/inorganic NP interactions due to the tunable size, surface and plamonic properties. In this talk, I will present the study of interaction of AuNPs with islet amyloid polypeptide (IAPP), which features in type 2 diabetes pathogenesis by self-assembly into fibrils and peptide-induced disruption of cell membranes. Amyloid fibrils share a distinct β-sheet structure, with the structural diversity controlled by the amino acid sequence. To elucidate the key mechanisms of amyloid self-assembly and provide unique viewpoints on the interactions with NPs, polymorphic fibril structures will firstly be discussed using amyloidogenic peptides that are designed based on the IAPP sequence. The observed amyloid fibrillation and hydrogelation controlled by the peptide structure also led to a proposed relationship between amyloid structure and self-assembly behaviour. Next, I will present the systematic study of IAPP/AuNP interactions, in which the strong binding is initiated by the metal-binding sequence in the hydrophilic peptide domain. Structural transition accelerated in a NP size-dependent manner also implies a facet-dependent IAPP/AuNP interaction. Based on these findings, liquid cell transmission electron microscopy was used for direct visualisation of the dynamic growth of AuNPs in presence of IAPP fibrils. The results show growth of branch(star)-shaped AuNPs in the presence of IAPP fibrils, suggesting a preferred nucleation site for Au binding and subsequent growth on the amyloid template.
153. RIKEN Lunch Seminar
"Vector mesons and chiral symmetry restoration"
Presented by Fabian Rennecke, Heidelberg University
Thursday, January 19, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Hiromichi Nishimura'
Vector mesons play a prominent role for the detection of chiral symmetry restoration in the quark-gluon plasma since their in-medium modifications are directly observable in dilepton spectra. However, a direct connection between their in-medium modifications and chiral symmetry restoration remains elusive. To shed some light on this, I will first address the question how chiral symmetry breaking and the light (vector) mesons emerge from the underlying quark-gluon dynamics. Then, I will present preliminary results on the in-medium spectral functions of the rho and a1 mesons obtained from analytic continuation of Euclidean two-point functions.
154. Particle Physics Seminar
"Ultra-Fast Silicon Detector for precise timing at CMS"
Presented by Nicolo' Cartiglia, Torino
Thursday, January 19, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Alessandro Tricoli'
In this seminar I will first review the physics case for a hermetic timing detector for charge particles to be installed in CMS in the years 2024-25 in preparation of the High Luminosity upgrade of the LHC accelerator (HL-LHC). Then I will present the possible technologies currently under studies for the timing detector and then I will concentrate on explaining the basics principles of Ultra-fast Silicon Detectors and their performances. I will conclude with a brief outline of the future R&D steps for the construction of the timing detector.
155. Particle Physics Seminar - SB/BNL Joint Cosmo Seminar
"Hunting down systematics in modern galaxy surveys"
Wednesday, January 18, 2017, 1:30 pm
Stony Brook University
With the next generation of wide field galaxy surveys, both spectroscopic and photometric, we expect to achieve unprecedented constraints on the expansion history of the universe and the growth of structure. Maximizing the flow of information from these rich datasets to constraints on our physical models requires accurate characterization of systematic uncertainties. First, we present a method for estimation of covariance matrices of galaxy clustering measurements with spectroscopic surveys. We show that our method enables us to generate accurate galaxy mocks needed for BAO and RSD analyses on nonlinear scales. Then, we present the main challenges in extracting cosmological information from lensing measurements of deep imaging surveys. We show that employing novel techniques in estimation of the point spread function can keep this major systematic under control. Finally, we discuss various approaches for improvement of the photometric redshifts for the imaging surveys. We demonstrate how the precision and accuracy of photometric redshifts can be greatly enhanced if we take advantage of combining different datasets.
156. Physics Colloquium
"And yet they attract: superconductivity in the presence of strong repulsion"
Presented by Andre-Marie Tremblay, University of Sherbrooke, Quebec, Canada
Tuesday, January 17, 2017, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: ''Wenhu Xu''
Band theory and the BCS theory of superconductivity are two pillars of the quantum theory of solids. High-temperature superconductors belong to a family of materials where both of these, band theory and BCS, fail. Layered organic materials of the BEDT family are another example of materials that are hard to understand within conventional approaches. The root cause of these failures can be traced to strong electronic repulsion. I will start from the simplest model that takes into account the competition between kinetic and potential energy, the Hubbard model. I will show how cluster generalizations of dynamical mean-field theory for this model shed light on these problems. The interaction-induced metal-insulator transition (Mott transition) can serve as an organizing principle for the phase diagrams.
157. Nuclear Theory/RIKEN Seminar
"Going with the flow: solving sign problems in complex space"
Presented by Paulo Bedaque, University of Maryland
Friday, January 13, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
We discuss a new approach to solve the sign problem arising in the Monte Carlo evaluation of path integrals. It is based on deforming the contour of integration into complex space. We will argue that for conceptual and numeric reasons it may be advantageous not to use the steepest descent manifolds (thimbles). We will discuss a variety of algorithms and their application to field theories with a fermionic sign problem and to quantum mechanical models, including real time dynamics.
158. Condensed-Matter Physics & Materials Science Seminar
"Transient Dynamics of Strongly Correlated Electrons After Sudden Excitations"
Presented by Marco Schiro, Institut de Physique Theorique (IPhT), CEA, Saclay, France
Friday, January 13, 2017, 1:30 pm
Seminar Room 2nd Floor Bldg 734
Hosted by: 'Robert Konik'
The development of pump-probe spectroscopies with femtosecond time resolution, which allows to track the dynamics of electronic degrees of freedom in solids under optical excitations, opens up a new window to understand strongly correlated materials and offers the intriguing possibility of controlling their properties with light, on ultra-fast time scales. Triggered by these advances, the interest around time dependent phenomena in quantum many body systems has recently substantially grown. In this talk will review recent progress in understanding transient dynamics of electrons in correlated metals, Mott Insulators and superconductors. I will show that quite generically these systems display very sharp dynamical transitions as a function of the external perturbation, in correspondence of which the lattice response and the sensitivity to density inhomogeneities can be greatly enhanced.
159. Particle Physics Seminar
"The muon g-2 experiment at Fermilab"
Friday, January 13, 2017, 10 am
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
There exists a long-standing, intriguing, discrepancy between the BNL E821 measurement and the Standard Model (SM) prediction for the muon anomalous magnetic moment, $a_{\mu} \equiv (g-2)/2$, at the level of about three standard deviations ($3\sigma$). To test this discrepancy, a new muon $(g-2)$ experiment E989 at Fermilab will improve the experimental uncertainty by a factor of four. Providing that the central value remains unchanged, the new measurement would result into more than $5\sigma$ discovery-level'' deviation from the SM. The experiment at Fermilab will employ the original BNL storage ring with an intense new muon source and state-of-the-art detector systems. I will review the current status of the design of new components and upgrades that are required to achieve the challenging precision goal of the experiment.
160. Particle Physics Seminar
"Analysis Methods in Neutrino Experiments"
Presented by Dr. Thomas Junk, Fermilab
Thursday, January 12, 2017, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Xin Qian''
Current and planned neutrino experiments address fundamental questions in the neutrino, astrophysical, nuclear, and new physics sectors with ambitious, large-scale facilities and detectors. Maximizing the sensitivity and physics reach of these experiments is the guiding principle for the design of the apparatus as well as the analysis techniques applied to infer results from the data. These experiments, however, pose challenges in this process: the data frequently have ambiguities and some quantities are not measurable, such as the momenta of outgoing neutrinos or recoiling nuclei. Detectors with high density and spatial granularity provide a large number of measured values for each event that must be sifted through to obtain even basic reconstructed quantities. The impact of the values of model parameters on the predicted event rates is not linear but is frequently oscillatory. Systematic uncertainties must be highly constrained in order to tease out small effects. To address these challenges, a variety of sophisticated techniques have been adapted from earlier experiments, such as well-established statistical methods and analysis techniques. New, innovative tools developed in other fields, such as deep-learning methods, are being applied to neutrino experiments. I will give a survey of some of the interesting developments being applied and planned for the future.
161. RIKEN Lunch Seminar
"Plasmon mass scale and linearized gauge field fluctuations in classical Yang-Mills theory"
Presented by Jarkko Peuron, University of Jyvaskyla
Thursday, January 12, 2017, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Heikki Mantysaari'
In this talk I discuss the determination of plasmon mass in classical real-time Yang-Mills theory on a lattice in 3 spatial dimensions. I compare 3 different methods to determine the plasmon mass : a hard thermal loop expression in terms of the particle distribution, an effective dispersion relation constructed from fields and their time derivatives, and by measuring oscillations between electric and magnetic field modes after artificially introducing a homogeneous color electric field. Due to plasma instabilities, small quantum fluctuations on top of the classical background may significantly affect the dynamics of the system. I argue for the need for a numerical calculation of a system of classical gauge fields and small linearized fluctuations in a way that keeps the separation between the two manifest. I derive and test an explicit algorithm to solve these equations on the lattice, maintaining gauge invariance and Gauss's law.
162. Physics Colloquium
"Searches for Decays of Heavy Higgs Boson to Gauge Bosons with the ATLAS detector"
Presented by Scott Snyder, BNL
Tuesday, January 10, 2017, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: 'Andrei Nomerotski'
Following the discovery of the Higgs boson in 2012, the ATLAS experiment at the LHC has been searching for signs of new physics related to the Higgs boson. One promising area is the seach for new, heavy Higgs-like scalars decaying to a pair of vector gauge bosons. This talk will summarize recent ATLAS searches for a heavy scalar decaying to two Z bosons, using the sqrt(s)=13 TeV data from Run 2
163. Nuclear Physics Seminar
"Phenomenology of Wigner distributions"
Presented by Andrei Belitsky, Arizona State University
Tuesday, January 10, 2017, 11 am
Small Seminar Room, Bldg. 510
Hosted by: ''Oleg Eyser''
We overview physics of nucleon phase space distributions and diverse high energy processes where they are accessible with current and future machines.
164. Nuclear Theory/RIKEN Seminar
"Prompt atmospheric neutrino flux and forward charm production in proton-nucleus collisions"
Presented by Anna Stasto, Penn State
Friday, January 6, 2017, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
The discoveries of the extraterrestrial neutrino flux by IceCube renewed interest in the precise evaluation of the background neutrinos which are produced in the atmosphere due the cosmic ray interactions. One of the most relevant processes at high energies is the charm and beauty production in proton-nucleus collisions which needs to be evaluated at very high energies where small x effects may become important. I will discuss a recent calculation of the forward charm production in pp and pA, and compare results from different models which include small x effects due to resummation and saturation. Comparison with the LHC data will be presented and nuclear effects on light nuclei will also be discussed. Finally, I will show the resulting prompt neutrino flux and its uncertainties and discuss the potential improvements.
165. Center for Functional Nanomaterials Seminar
"DNA Assembled Nanoparticle Clusters for Nanomedicine"
Presented by Liangcan He, University of Colorado Boulder
Monday, December 19, 2016, 1:30 pm
CFN, Bldg 735, Conference Room A, 1st Floor
Hosted by: ''Oleg Gang''
In this talk, I will describe the use of nucleic acids to assemble different types of nanocrystals for theranostic applications. In the first part, I will talk about our work on coupling gold nanoparticles (AuNPs) and gold nanostars (AuNSs) to silica-coated upconverting nanoparticles (UCNPs) and their effect on photoluminescence. The experimental and simulation studies showed that the orientation and distance of the UCNP with respect to the core and arms of the gold nanostructures played a significant role in photoluminescence. Also, the AuNS-UCNP assemblies were able to cause rapid gains in temperature of the surrounding medium enabling their potential use as a multi-therapy agent. Then, photodynamic therapy (PDT) was induced by embedding singlet oxygen photosensitizers in mesoporous silica shells on the UCNPs. It showed the Au-UCNP clusters with optimized plasmon resonance and compositions could provide both in vitro imaging contrast and combined cell killing through simultaneous photothermal (PTT) and photodynamic (PDT) therapy under NIR light photoexcitation. In addition to the Au-UCNP studies, I will also describe our recent efforts on building well-defined core-satellite porphyrinic metal-organic framework (MOF)-UCNP assemblies by DNA templating. In this work, UCNPs were well organized around a centrally located MOF nanoparticles. Under NIR irradiation, the emitted light from the assembled UCNPs excited each core MOF NP to produce singlet oxygen (1O2) at significantly greater amounts than that produced from simply mixing UCNPs and MOF NPs, demonstrating their promise as theranostic photodynamic agents. In the second part, I will briefly introduce my graduate work in the Ph.D. study on noble metal nanoparticles-MOFs hybrid materials for SERS detecting and multifunctional drug delivery vehicles.
166. Nuclear Theory/RIKEN Seminar
"Proton fluctuations and multi-particle rapidity correlations"
Presented by Kevin Dusling, PRL
Friday, December 16, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Heikki Mantysaari'
The effect of intrinsic fluctuations of the proton saturation momentum scale on event-by-event rapidity distributions in small systems is explored. Saturation scale fluctuations generate an asymmetry in the single particle rapidity distribution in each event resulting in genuine n-particle correlations. We introduce a color domain model that naturally explains the centrality dependence of the two-particle rapidity correlations recently measured by ATLAS, constraining the probability distribution of saturation scale fluctuations in the proton. Predictions for n=4, 6 and 8 particle rapidity correlations find that the four- and eight-particle cumulant change sign at intermediate multiplicities, a signature which could be tested experimentally.
167. HET/RIKEN Seminar
"The Fate of Axion Stars"
Presented by Hong Zhang, Ohio State University
Wednesday, December 14, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Pier Paolo Giardino''
168. Nuclear Physics Seminar
"Evidence for light-by-light scattering in 5.02 TeV Pb+Pb collisions with the ATLAS detector at the LHC"
Presented by Mateusz Dyndal, DESY
Tuesday, December 13, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Peter Steinberg'
I report evidence for light-by-light scattering, using 480ub^−1 of 5.02 TeV Pb+Pb collision recorded by the ATLAS experiment at the LHC. After background data at subtraction and analysis corrections, the cross section of gamma gamma-> gamma gamma process for photon transverse momentum, E_T > 3 GeV, photon pseudorapidity, |η| < 2.4, diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower than 2 GeV and diphoton aco- planarity below 0.01, has been measured to be 70 ± 20 (stat.) ± 17 (syst.) nb, which is in agreement with the SM prediction of 49 ± 10 nb.
169. Nuclear Theory/RIKEN Seminar
"Hydrodynamics, the gradient expansion and transient modes"
Presented by Michal Heller, Perimeter Institute
Friday, December 9, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
I will discuss recent developments at the interplay between hydrodynamic gradient expansion and transient modes in expanding plasma.
170. RIKEN Lunch Seminar
"Analytic Results for Color Glass In Space-Time Coordinates"
Presented by Rainer Fries, Texas A&M University
Thursday, December 8, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Heikki Mantysaari''
I will start by reviewing some previous results for the McLerran-Venugopalan model for nuclear collisions solved analytically in space-time coordinates. I will then discuss some recent work on initial angular momentum in the resulting Yang-Mills system, which leads to an interesting picture of gluon flow in the event plane. I will also describe further evolution of these results in fluid dynamics. Time permitting I will touch on ongoing efforts to construct an event generator based on analytic solutions.
171. Joint: YITP/HET
"Enhancing searches for beyond the Standard Model physics at the LHC"
Presented by Michele Papucci, Berkeley
Wednesday, December 7, 2016, 2:30 pm
YITP Seminar Room
In this talk I'll present recent work on improving the capabilities for looking for new physics at the LHC, both for exotics BSM signals (hidden valleys) and for Dark Matter. I will also discuss soon to be publicly available tools for connecting LHC results with theoretical models.
172. Nuclear Theory/RIKEN Seminar
"Squeeze Out"
Presented by Ron Longacre, BNL
Wednesday, December 7, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: '''Heikki Mantysaari'''
Squeeze out happen when the expanding central fireball flows around a large surface flux tube in a central Au-Au collision at RHIC. We model such an effect in a flux tube model. Two particle correlations with respect to the $v_2$ axis formed by the soft fireball particles flowing around this large flux tube is a way of measuring the effect.
173. Nuclear Physics Seminar
"Quarkonium and Open Heavy Flavor productions at collider energies in Small-x formalism"
Presented by Kazuhiro Watanabe, Old Dominion University/Jefferson Lab
Tuesday, December 6, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Oleg Eyser'
Heavy quark pair production in high energy proton-nucleus (pA) collisions provides valuable information on the gluon saturation dynamics at small-x of a heavy nucleus. Nowadays, large amounts of data of quarkonium, open heavy flavor, and decay lepton accumulated by RHIC and LHC enable us to examine the calculations in Small-x formalism or Color Glass Condensate (CGC). Essentially, the calculations of heavy quark pair production have been based on the Small-x/CGC framework at leading order (LO) with the running coupling Balitsky-Kovchegov equation (rcBK) which includes a subset of next-to-leading order (NLO) correction. A main difference between pp and pA collisions is the choice of the initial saturation scale in the rcBK equation. The recent theoretical computations have gradually clarified the gluon saturation effect in pA collision by comparing with data on the transverse momentum spectrums and the nuclear modification factors measured at RHIC and LHC. In this talk, we will review the recent studies of heavy quark pair production in the Small-x/CGC framework and discuss the relevant topical issues. Furthermore, we will discuss the Sudakov implementation in Small-x formalism which has received attention in recent years. I will show that the Sudakov effect on top of the saturation effect is indeed indispensable for Upsilon production.
174. Nuclear Theory/RIKEN Seminar
"Renormalization-group flow of the effective action of cosmological large-scale structures"
Presented by Stefan Flörchinger, Heidelberg
Friday, December 2, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: '''Heikki Mantysaari'''
The large scale structure of the universe forms a particular type of fluid which is governed by the properties of dark matter. I discuss how one can derive renormalization group equations for the effective action that describes the statistical properties of this fluid. Taking into account in particular effective viscosity and sound velocity terms leads to an improved framework to determine density and velocity power spectra.
175. CFN Colloquium
"The emergence of hybrid-perovskites for low-cost, high-efficiency optoelectric devices"
Presented by Aditya D. Mohite, Los Alamos National Laboratory
Thursday, December 1, 2016, 4 pm
CFN, Bldg 735, Seminar Room, 2nd Floor
Hosted by: ''''Matthew Sfeir''''
Hybrid (inorganic--organic) perovskites have demonstrated an extraordinary potential for clean sustainable energy technologies and low--cost optoelectronic devices such as solar cells; light emitting diodes, detectors, sensors, ionic conductors etc. In spite of the unprecedented progress in the past six years, one of the key challenges that exist in the field today is the large degree of processing dependent variability in the structural and physical properties. This has limited the access to the intrinsic properties of hybrid perovskites and led to to multiple interpretations of experimental data. In addition to this, the stability and reliability of devices has also been strongly affected and remains an open question, which might determine the fate of this remarkable material despite excellent properties. In this talk, I will describe our recently discovered approach for thin--film crystal growth as a general strategy for growing highly crystalline, bulk--like thin--films of both three--dimensional (3D) and layered two--dimensional (2D) hybrid perovskites that overcomes the above issues by allowing access to the intrinsic charge and energy transport processes within the perovskite thin--films and results in reproducible and stable high performance optoelectronic devices.
176. Condensed-Matter Physics & Materials Science Seminar
"Complexity in Spin-Frustrated Rock-Salt Manganites"
Presented by Alexandros Lappas, Institute of Electronic Structure and Laser, Foundation for Research & Technology, Greece
Thursday, December 1, 2016, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: 'Emil Bozin'
Complexity in transition metal oxides is the outcome of simultaneously active electron degrees of freedom (spin-charge-orbital) and their evolution under the restrictions imposed by the geometry of the underlined crystal lattice. Consequently, the materials' response to competing states requires that we assess structural correlations across a wide range of length and time scales. Taking advantage of cutting-edge structural facilities accessed at neutron [1, 2], synchrotron X-ray [3] and electron microscopy [4] labs we address current limitations in understanding the crystallographic structure of layered rock-salt type triangular-lattice manganites of the AMnO2 type (A= Na, Cu). The unexpected coexistence of long- and short-range magnetic correlations [3, 5] due to two major opposing effects (elastic vs. magnetic exchange) of similar magnitude, lead to nearly equivalent, competing structural phases enabling infinitesimal quenched disorder to locally lift the differing degree of inherent frustration in the parent AMnO2 phase. These manganites provide a paradigm of a rarely observed nanoscale inhomogeneity in an insulating spin system, an intriguing complexity of competition due to geometrical frustration. The dramatic impact of topology and site-disorder on frustrated magnetism is further demonstrated by the hydrated variant of the NaMnO2 antiferromagnet, which gives way to a strongly interacting spin-glass state, indicative of the subtle balance of competing processes in multivalent two-dimensional systems [6]. [1] M. Giot et al., Phys. Rev. Lett. 2007, 99, 247211. [2] C. Vecchini et al., Phys. Rev. B 2010, 82, 094404. [3] A. Zorko et al., Nat. Commun. 2014, 5, 3222. [4] A.M. Abakumov et al., Chem. Mater. 2014, 26, 3306. [5] A. Zorko et al., Sci. Rep. 2015, 5, 9272. [6] I. Bakaimi et al., Phys. Rev. B 2016, 93, 184422.
177. HET/RIKEN Seminars
"Heavy meson decays to light resonances"
Presented by Luka Leskovec, University of Arizona
Wednesday, November 30, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Mattia Bruno''
Lattice QCD calculations of electroweak decays with single, strong-interaction-stable hadrons in the initial and final state have recently reached a high level of precision. Many phenomenologically important decays, however, involve hadronic resonances, and their naive analysis on the lattice leads to uncontrolled systematic errors. Recent theoretical developments in the finite-volume treatment of $1 \to 2$ transition matrix elements now enable us to perform rigorous lattice calculations of electroweak decays to light resonances such as the $\rho$. After presenting the Briceno-Hansen-Walker-Loud formalism, I will discuss our numerical implementation for the $D\to\rho \ell \nu$ and $B\to\rho \ell \nu$ decays, where we aim to quantify the effect of the unstable nature of the $\rho$. Our calculations are performed on a gauge ensemble with 2+1 flavors of clover fermions with a pion mass of ~320 MeV and a lattice size of ~3.6 fm.
178. Physics Colloquium
"Isolated quantum systems in extreme conditions: From heavy-ion collisions to ultracold quantum gases"
Presented by Juergen Berges, University of Heidelberg
Tuesday, November 29, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: ''Rob Pisarski''
Isolated quantum systems in extreme conditions can exhibit characteristic common properties despite dramatic differences in key parameters such as temperature, density, field strength and others. The existence of universal regimes, where even quantitative agreements between seemingly disparate physical systems can be observed, drives a remarkable convergence of research activities across traditional lines of specialization. I will describe the concerted research efforts by the recently established Heidelberg Collaborative Research Center ISOQUANT in collaboration with BNL and discuss recent developments concerning the thermalization dynamics of non-Abelian plasmas and ultracold atoms.
179. Nuclear Physics Seminar
"Accessing Gluon Polarization with Di-jets: Present and Future"
Presented by Brian Page, BNL
Tuesday, November 29, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Oleg Eyser'
Despite extensive theoretical and experimental effort, a detailed understanding of how the proton spin is built up from the spins and orbital angular momenta of its constituents remains elusive. Polarized fixed-target deep inelastic scattering data has constrained the contribution from quark and anti-quark helicities to be roughly 30% for parton momentum fractions greater than 10^-3, while inclusive jet and $\pi^0$ asymmetry results from the STAR and PHENIX experiments at RHIC have placed strong constraints on the gluon helicity contribution for momentum fractions greater than 0.05. This talk will detail the extension of STAR inclusive jet measurements to correlated di-jet measurements, which better constrain the initial partonic kinematics. Recently released di-jet asymmetry results from STAR will be presented and the status of future measurements will be discussed. Di-jet asymmetry measurements will also play an important role in constraining the gluon helicity contribution to the proton spin at a future Electron-Ion Collider, and the prospects for such measurements will be outlined.
180. Condensed-Matter Physics & Materials Science Seminar
"X-ray Photon Correlation Spectroscopy at Large Angles"
Presented by Mark Sutton, McGill University
Tuesday, November 22, 2016, 1:30 pm
ISB Bldg. 734, Conf. Room 201 (upstairs)
Hosted by: 'Mark Dean'
Xray photon correlation spectroscopy (XPCS) has proven to be a powerful way to study time correlations in equilibrium systems. The straight forward extension to two-time correlations has also proven very useful. To date, most XPCS work has been done using small-angle x-ray scattering (SAXS). As with conventional x-ray diffraction, the information in disordered Bragg peaks (large angle scattering) often contains more information but it can be harder to interpret. In this talk, I will discuss several results using large angle XPCS which explore some of the complications and the resulting extra information obtained.
181. Condensed-Matter Physics & Materials Science Seminar
"Probing the magnetic structure of EuPtIn4 via x-ray resonant magnetic scattering"
Presented by Jose Renato Mardegan, Deutsche Elektronen-Synchrotron (DESY), Germany
Tuesday, November 22, 2016, 11 am
ISB Bldg. 734, Seminar Rm. 201 (upstairs)
Hosted by: ''Ian Robinson''
The search for fascinating materials with interesting electronic and magnetic properties has led to an enormous development in diverse areas of condensed matters physics. In particular, the Indium-rich materials containing rare-earth elements can host exotic physical phenomena emerging from the competition and/or cooperation of several physical mechanisms such as the Ruderman-Kittel-Kasuya-Yosida (RKKY) magnetic interaction, heavy fermion (HF) behavior, crystalline electric field (CEF) and Kondo effects[1,2].Since the magnetic ordering and the screening of f-electrons have an important role in the ground state properties of these materials, the magnetic structure determination can be a powerful tool to understand how the moments of the magnetic ions are interacting among each other. In this sense, x-ray resonant magnetic scattering (XRMS) technique was employed to solve the magnetic structure at low temperature of the new intermetallic EuPtIn4 compound. At the resonant energy of the Eu ion (7617 eV – L2 edge), magnetic incommensurate (ICM) reflections with propagation vector type (1/2, 1/2, τ) with τ ~ 0.427 were observed. Temperature and magnetic field dependence performed at the magnetic reflections reveal an AFM coupling with a Néel temperature TN = 13.1 K and a spin flop transition above 3 T, respectively. In addition, we do not observe any magnetic anomalies related to a second phase transition as suggested in the previously reported macroscopic measurements [3,4]. The ICM phase observed at low temperature is due to geometric frustration of the Eu ions in which the RKKY exchange interaction cannot be simultaneously satisfied. Although the EuPtIn4 compound displays similar properties to a heavy fermion compound such as exotic magnetic structure and enhancement of Sommerfeld coefficient, further investigation must be performed in this new series of materials.[1] Z. Fisk, et al., Proc. Natl. Acad. Sci. USA 92, 6663 (1995).[2] P. Coleman, Handb
182. Nuclear Physics Seminar
"Chromodynamic Rutherford Scattering?"
Presented by John Dainton, Cockcroft Insitute, University of Liverpool
Tuesday, November 22, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: ''Oleg Eyser''
It is asserted that precision measurements of exclusive processes in high-luminosity electron-hadron interactions are the way forward in understanding hadron physics in Nature. Such processes involve the control of more than one scale and thereby enable experimental analysis in terms of phenomenology which can then challenge theoretical calculation in specific ways and on which it will be possible to build a full understanding of chromodynamic mechanism. The presentation is built on initial steps in an on-going analysis of published measurements of exclusive meson production at the HERA ep collider. It already can be seen to indicate that the assertion could well be well justified with precision measurements in the future in a high luminosity electron hadron collider.
183. Particle Physics Seminar
"The Short Baseline Neutrino program: laying the groundwork for DUNE"
Presented by Georgia Karagiorgi, Columbia University
Tuesday, November 22, 2016, 9:30 am
Small Seminar Room, Bldg. 510
Hosted by: '''Xin Qian'''
The Short Baseline Neutrino (SBN) Program comprises three liquid argon time projection chamber detectors which are planning to study neutrinos from the Booster Neutrino Beamline at Fermilab, at three different locations close to the neutrino production. The trio of detectors will be able to perform precise neutrino cross section measurements, and search for short-baseline neutrino oscillations and other non-standard effects, addressing pressing questions in the field of neutrino oscillations. The SBN detectors also share the same detector technology as the future, O(100) times larger detector that will be employed for the Deep Underground Neutrino Experiment. They therefore provide a testbed for R&D and for demonstrating the liquid argon TPC technology and its scalability. This seminar will highlight selected physics and R&D opportunities with SBN.
184. Condensed-Matter Physics & Materials Science Seminar
"Tracking chemical reactions with time-resolved x-ray spectroscopic techniques"
Presented by Tadese Abebaw Assefa, European XFEL Laboratory, Germany
Monday, November 21, 2016, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: ''Ian Robinson''
Transition metal compounds play a significant role in many chemical and biologically relevant processes. Hereby charge transfer, ligand detachment and attachment processes are fundamental ingredients, which often determine the outcome of a given chemical reaction. We investigated aqueous ferrocyanide ([FeII(CN)6]4-) ions, which undergoes charge transfer and ultrafast ligand dissociation upon irradiation of 266 and 355 nm laser light. Time-resolved (TR) x-ray absorption and emission spectroscopies (XAS and XES) deliver information about structural and electronic changes in real-time implemented to follow the chemical reaction. Synchrotron-based studies are limited with 100ps time resolution enables us to disentangle simultaneous photoproducts formed after 266 nm laser excitation. Furthermore, we investigated the ultrafast ligand dissociation of aqueous ferrocyanide ions upon irradiation of 355 nm laser light at the x-ray Free Electron Laser facility (SACLA, Japan). Based on a comparison of the simulated pre-edge peaks of 1s→3d transition with the experimental data, we concluded that the reaction pathway commences via ligand detachment resulting pentacoordinated intermediate complex ([FeII(CN)5]3-), followed by the formation of the long-lived photoaquated complex ([FeII(CN)5(H2O)]3-). The ligand detachment and attachment process takes 12.43 ± 5.77 ps. TR XES results also reveal spin state change in the intermediate state. Combining these findings we interpret the consecutive steps of ligand exchange mechanism for ferrocyanide ions. Also, we characterise the molecular structure of photoexcited [FeII(terpy)2]2+ molecule via TR Extended X-ray absorption fine structure (EXAFS). The data analysis in energy space used two structural model expansions which are the representations of DFT predicted 5E and 5B2 quintet high spin states. After statistical evaluation of the two models, the 5E high spin state model is in better agreement with experimental data. The ener
185. Nuclear Theory/RIKEN Seminar
"Phase structure and dynamics of dense QCD"
Presented by Armen Sedrakian, Frankfurt
Friday, November 18, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''''Heikki Mantysaari''''
In the first part of the talk I will discuss recent computations of the transport coefficients of dense QCD from the Kubo formalism on the basis of a two-flavor model of QCD. The second part of the talk will discuss the properties of compact stars featuring color superconducting phases of dense QCD. This will include modeling of massive compact stars, neutrino cooling of such stars, and possible signatures of a phase transition within the QCD phase diagram in the X-ray data from the young neutron star in Cassiopea A.
186. Particle Physics Seminars- SB/BNL Joint Cosmo Seminar
"A more precise and accurate route from sky images to cosmological constraints"
Presented by Gary Bernstein, University of Pennsylvania
Thursday, November 17, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Anze Slosar''
Current (e.g. DES) and future (e.g. LSST, Euclid) experiments aim to convert multiband images of the sky into precise constraints on cosmological models, neutrino masses, and modifications of general relativity. This standard path for this inference involves making point estimates of the galaxies' redshifts (from observed colors) and weak gravitational lensing distortions (from observed morphologies), then combining these into various cross-correlations and other summary statistics that are compared to numerical simulations of the Universe. These estimators require a slew of empirical corrections to various biases, and have yet to demonstrate accuracies sufficient to reduce biases below systematic errors. I describe two steps to greatly simplify this process and eliminate the need for simulation-based calibration of estimators: first, a practical means to estimate the joint posterior probability of a galaxies' redshift and line-of-sight lensing; second, a method to sample from the posterior distribution of all mass distributions and cosmologies conditional on the galaxy density and lensing data. The main advantages of the new scheme include improved lensing and photo-z accuracy (to the required part-per-thousand level), recovery of non-Gaussian information that is lost in the usual 2-point summary statistics, and correct propagation of uncertainties (including photo-z uncertainties) into the cosmological inferences.
187. Nuclear Theory/RIKEN Seminar
"Quantum-field-theoretical approach to shear and bulk relaxation times"
Presented by Alina Czajka, McGill
Thursday, November 17, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Heikki Mantysaari''
The shear and the bulk relaxation times are important ingredients of the second order hydrodynamics whose success in heavy ion phenomenology is unquestioned. Unlike viscosites themselves, field theoretical calculations of the relaxation times are hard to come by in literature, especially for the bulk relaxation time. In this talk, we report two field-theoretical analyses involving the shear and the bulk relaxation time. First, by carefully examining the analytic structure of the stress-energy tensor response functions, we have been able to derive, for the first time, a Kubo formula involving both the shear and the bulk relaxation times. Second, by evaluating the Kubo formula within the massless scalar theory, we have so far been able to calculate the shear relaxation time in a simple form. We will then show how this calculation can be extended to calculate the bulk relaxation time as well.
188. Physics Colloquium
"Low-energy Precision Physics and the Role of Lattice QCD"
Presented by Harmut Wittig, University of Mainz
Tuesday, November 15, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: 'Peter Petreczky'
The particle content of the Standard Model has been completely established following the discovery of the Higgs boson. While the Standard Model describes all known phenomena in accelerator-based experiments, many important questions are left unanswered. In this talk I describe several attempts to detect signals for physics beyond the Standard Model using precision experiments at low energies. Special attention is given to the anomalous magnetic moment of the muon and the role of lattice QCD in quantifying the hadronic uncertainties in its theoretical prediction.
189. Nuclear Physics Seminar
"Is there a low p_T anomaly in the pion momentum spectrum at LHC?"
Presented by Pasi Huovinen, University of Wroclaw
Tuesday, November 15, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Oleg Kjeld'
The low p_T part of the pion spectrum measured by the ALICE collaboration has turned out to be very difficult to reproduce using conventional fluid dynamical approaches. In this talk I discuss how the finite width of rho mesons affects the yield of rhos and the distribution of pions originating from rho decays, and how inclusion of the finite width in the description of resonances may help to explain the low p_T pion data.
190. Particle Physics Seminar: SB/BNL Joint Cosmo Seminar
"Revealing CII Emission with LSS Cross-correlations"
Presented by Anthony Pullen, NYU
Thursday, November 10, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: '''''Anze Slosar'''''
The CII emission line tends to be the brightest line in star-forming galaxies, making it an ideal tracer of large-scale structure. Through the method of intensity mapping, astronomers hope to map CII emission at cosmological redshifts and large volumes, making CII and unprecedented probe of cosmology and reionization. However, the various models of the expected CII emission are highly uncertain by orders of magnitude, limiting our ability to predict how well potential CII surveys could probe large-scale structure. In this talk, I will present our measurement of excess emission from large scales at redshift z=2.5 potentially attributable to CII emission. This excess emission was measured by cross-correlating the 545 GHz broad-band microwave map from the Planck satellite and high-redshift quasars from the Sloan Digital Sky Survey. I will also discuss future opportunities with CII intensity mapping.
191. RIKEN Lunch Seminar
"An overview of lattice field theory applications to dark matter searches"
Presented by Enrico Rinaldi, RBRC
Thursday, November 10, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Hiroshi Oki''
192. Environmental & Climate Sciences Department Seminar
"Observational constraints on mixed-phase clouds imply higher climate sensitivity"
Presented by Ivy Tan, Yale Univ.
Thursday, November 10, 2016, 11 am
Conference Room Bldg 815E
Hosted by: 'Robert McGraw'
Mixed-phase clouds are comprised of both liquid droplets and ice crystals. For a given total water content, mixed-phase clouds with higher liquid water contents are optically thicker and therefore more reflective to sunlight compared to those with higher ice water contents. This is due to the fact that liquid droplets tend to be smaller in size and more abundant than ice crystals in Earth's atmosphere. Given the ubiquity of mixed-phase clouds, the ratio of liquid to ice in these clouds is expected to be important for Earth's radiation budget. We determine the climatic impact of thermodynamic phase partitioning in mixed-phase clouds by using five pairs of simulations run with CAM5/CESM. Of the five pairs of simulations, the thermodynamic phase partitioning of two of the simulations were constrained to better agree with observations from CALIPSO. The other three pairs of simulations include a control simulation, as well as an upper and lower bound simulation with maximally high and low amounts of mixed-phase cloud liquid fractions. An analysis of the simulations shows that a negative "cloud phase feedback" that occurs due to the repartitioning of cloud droplets and ice crystals under global warming is weakened when mixed-phase clouds initially contain a higher amount of liquid. Simulations that exhibited weaker cloud phase feedbacks also had higher climate sensitivities. The results suggest that an unrealistically strong cloud phase feedback leading to lower climate sensitivities may be lurking in the many climate models that underestimate mixed-phase cloud liquid fractions compared to observations.
193. Particle Physics Seminar
"An improved ultracold neutron bottle for measuring the neutron lifetime"
Thursday, November 10, 2016, 10 am
Small Seminar Room, Bldg. 510
Hosted by: '''Xin Qian'''
The neutron beta decay lifetime is an important parameter in theories of weak interaction and big bang nucleosynthesis. To this end, many experiments over the past several decades have sought to improve the precision of this value. Ultracold neutrons, or UCN, are neutrons with extremely low energies which can be contained by material walls; these have provided us with a useful tool in measuring the neutron lifetime. The most recent set of experiments have demonstrated a 6sigma discrepancy between two lifetime values, each obtained using a different method of measurement. The UCNtau experiment at Los Alamos Neutron Science Center, is a bottling experiment which is designed to hold UCN within a 600 liter magnet-lined bowl to store the neutrons through magnetogravitational trapping. The open topped nature of the storage vessel allows for detectors to be lowered into the UCN volume to take in-situ measurement of the surviving UCN after varying storage times. This talk will cover newly presented results from the most recent UCNtau experiment data.
194. HET/RIKEN Seminars
"When the Higgs meets the Top"
Presented by Chung Kao, University of Oklahoma
Wednesday, November 9, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Pier Paolo Giardino''
195. Particle Physics Seminar
"TBA"
Presented by Jo Bovy
Wednesday, November 9, 2016, 1:30 pm
Stony Brook University
Hosted by: 'Neelima Sehgal'
196. Physics Colloquium
"Skyrmions and Nuclei"
Presented by Nick Manton
Tuesday, November 8, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: 'Robert Pisarski'
Nuclear forces are mediated by pions. As pions are light compared to nucleons and other mesons, they are treated as approximate Goldstone bosons in an effective field theory (EFT) with spontaneously broken SO(4) chiral symmetry. Generically, the nonlinear field equations of EFT have topological soliton solutions called Skyrmions, which we identify as the intrinsic structures of nucleons or larger nuclei. The quantum states of the unit-winding, spherical Skyrmion represent protons and neutrons with spin half. Skyrmions of many higher winding numbers are also known, having beautiful symmetries, and sometimes showing alpha-particle or other clustering. The classical solutions have definite location, orientation, and pion field orientation, so we quantize the collective coordinates to obtain states with definite momentum, spin and isospin. A Skyrmion's symmetry restricts its allowed spin/isospin combinations (Finkelstein—Rubinstein constraints). The recent inclusion of vibrational degrees of freedom has helped to create a reasonable model for Oxygen-16 and its excited states.
197. Nuclear Physics & RIKEN Theory Seminar
"Glue spin from lattice QCD"
Presented by Yi-Bo Yang, University of Kentucky
Friday, November 4, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: '''Heikki Mantysaari'''
I will present the result of the glue spin in proton from the lattice QCD simulation, and also the renormalization and matching issues. The lattice calculation is carried out with valence overlap fermions on 2+1 flavor DWF gauge configurations on four lattice spacings and four volumes including an ensemble with physical values for the quark masses. The glue spin $S_G$ in the $\overline{\text{MS}}$ scheme is obtained with the 1-loop perturbative matching. I will also discuss the generic strategy and possible difficulties of calculating the glue helicity on the lattice, from the large momentum effective theory to the lattice simulations.
198. Condensed-Matter Physics & Materials Science Seminar
"Surface X-ray Diffraction for Operando Characterization of Chemical Reactions on Surfaces""
Presented by Roberto Felici, Istituto SPIN - CNR, Italy
Friday, November 4, 2016, 11 am
ISB Bldg. 734, Sem. Rm. 201 (upstairs)
Hosted by: ''''Ian Robinson''''
X-rays are an ideal probe for studying structural properties of matter and, thanks to the brilliance of synchrotron sources, they are also employed to determine the atomic structure and morphology of surfaces and interfaces. Surface x-ray diffraction has been originally developed to determine the static structure of surfaces. However with the development of x-ray sources, detectors and analysis tools it is now possible to characterise in detail processes which occur at surfaces. Aim of this talk is to present recent results obtained at the id03 surface diffraction beamline of the ESRF dealing with the in-situ characterization of the structure and morphology of a catalyst during a surface reaction. Examples will deal with heterogenous catalytic oxidation of CO on single crystal surfaces /1,2/ and supported nanoparticles /3/ References 1 R. van Rijn et al., Phys. Chem. Chem. Phys. 13 (2011) 13167 2 B.L. Hendriksen et al., Nat. Chem. 2 (2010) 730 3 O. Balmes, et al., Phys. Chem.Chem. Phys. 14 (2012) 4796
199. RIKEN Lunch Seminar
"Form Invariance, Topological Fluctuations and Mass Gap of Yang-Mills Theory"
Presented by Yachao Qian, Stony Brook University
Thursday, November 3, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Hiromichi Nishimura''
We study the quantum Yang-Mills theory in the presence of topologically nontrivial backgrounds. The topologically stable gauge fields are constrained by the form invariance condition and the topological properties. Obeying these constraints, the known classical solutions to the Yang-Mills equation in the 3- and 4-dimensional Euclidean spaces are recovered, and the other allowed configurations form the nontrivial topological fluctuations at quantum level. Together, they constitute the background configurations, upon which the quantum Yang-Mills theory can be constructed. We demonstrate that the theory mimics the Higgs mechanism in a certain limit and develops a mass gap at semi-classical level on a flat space with finite size or on a sphere.
200. HET/RIKEN Seminars
"Neutrinoless double beta decay from lattice QCD"
Presented by Amy Nicholson, UC Berkeley
Wednesday, November 2, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Mattia Bruno''
201. Nuclear Physics Seminar
"Photon-tagged jet production in 5.02 TeV Pb+Pb and pp"
Presented by Peter Steinberg, BNL
Tuesday, November 1, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: ''Jia Jiangyong''
Nuclear collisions which produce a high transverse momentum (p_T) prompt photon offer a useful way to study the dynamics of the hot, dense medium produced in these events. Because photons do not carry color charge, they are unaffected by the hot, dense medium. Thus, the outgoing photon serves as a tag of the initial parton flavors, and measures the initial parton pT before they are quenched by their passage through the medium In 2015, ATLAS sampled 0.49 nb-1 and 26 pb-1 of Pb+Pb and pp data at 5.02 TeV, respectively, with a high-level photon trigger that selects p_T>25 GeV photons with high efficiency. The larger prompt photon cross-section and integrated luminosity with respect to 2.76 TeV data allow for new, differential studies of photon-jet correlations. In this talk, ATLAS results on photon-jet azimuthal and pT balance will be presented using pT > 60 GeV photons and R=0.4, pT > 30 GeV jets. Double-differential distributions of the jet-to-photon p_T ratio, x_Jg, and of the azimuthal difference, $\Delta\phi$, will be presented as a function of photon p_T and event centrality.
202. Nuclear Theory/RIKEN Seminar
"Perturbative QCD and beyond: Bose-Eitstein correlation and $v_n$ at any n"
Presented by Genya Levin, Tel Aviv University
Friday, October 28, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Heikki Mantysaari''
"The REDTOP Experiment: Rare Eta Decays with a TPC for Optical Photons"
Presented by Dr. Corrado Gatto, FNAL and INFN
Friday, October 28, 2016, 10 am
Large Conference Room Bldg. 911B
Hosted by: '''Wolfram Fischer'''
The eta meson is almost unique in the particle universe since it is a Goldstone boson and the dynamics of its decay are strongly constrained. Because the eta has no charge, decays that violate conservation laws can occur without interfering with a corresponding current. The integrated eta meson samples collected in earlier experiments have been less than 1e8 events, limiting considerably the search for such rare decays. A new experiment, REDTOP, is being proposed at the proton booster of Fermilab with the intent of collecting more than 1e12 triggers/year for studies of rare eta decays. Such statistics are sufficient for investigating several symmetry violations, and for searches for new particles beyond the Standard Model. The physics program, the accelerator systems and the detector for REDTOP will be discussed during the seminar.
"Picturing Physics: How Topology Helps Untangle the Puzzle of the Shapes of Things"
Moira Chas, Stony Brook University
Thursday, October 27, 2016, 4:30 pm
Hamilton Seminar Room, Bldg. 555
205. Condensed-Matter Physics & Materials Science Seminar
"Driven Dirac Materials"
Presented by Alexander Balatsky, Los Alamos National Laboratory
Thursday, October 27, 2016, 1:30 pm
Bldg. 734, ISB Seminar Rm. 201 (upstairs)
Hosted by: 'Robert Konik'
Dirac Materials exhibit nodes in the spectra that result in the strong energy dependence of the Density of States (DOS). Collective many body instabilities in Dirac Materials are controlled by the dimensionless DOS. Hence the driven and nonequilibrium Dirac Materials offer a platform for investigation of collective instabilities of Dirac nodes via controlled tuning of the coupling constants with drive. I will present the results of investigation of the many body instabilities, like excitonic instabilities, in driven Dirac Materials. Recent optical pump experiments are consistent with the creation of long lived states away from equilibrium in Dirac Materials.
206. RIKEN Lunch Seminar
"Hybrid approach to relativistic heavy-ion collisions at the RHIC BES energies"
Presented by Chun Shen, BNL
Thursday, October 27, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: '''Hiroshi Oki'''
Using a hybrid (viscous hydrodynamics + hadronic cascade) framework, we model the bulk dynamics of relativistic heavy-ion collisions at the RHIC BES collision energies, including the effects from non-zero net baryon current and its dissipative diffusion during the evolution. The framework is in full 3+1 dimension which allows us to study the non-trivial longitudinal structure and dynamics of the collision systems, for example, the baryon stopping/transport. The collision energy dependence of hadronic chemistry, identified particle spectra, anisotropic flows, and HBT radii is studied from 200 GeV to 19.6 GeV. Effects of breaking boost-invariance, net-baryon current, and its related diffusion on hadronic observables will be addressed. Finally, flow prediction for recent d+Au collisions at the BES energies will be presented within the same framework.
207. HET/RIKEN Seminars
"Collider signatures of flavorful Higgs bosons"
Presented by Stefania Gori, University of Cincinnati
Wednesday, October 26, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Pier Paolo Giardino''
208. Special Nuclear Theory/RIKEN seminar
"A new relativistic viscous hydrodynamics code for high-energy heavy-ion collisions"
Presented by Chihi Nonaka, Nagoya University, Japan
Wednesday, October 26, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: ''Chun Shen''
Relativistic hydrodynamic simulations play a key role in exploring the QGP bulk property and the QCD phase transition from analyses of high-energy heavy-ion collisions at RHIC and LHC. From the intensive study based on relativistic viscous hydrodynamic models with event-by-event initial fluctuations, we can extract detailed information of the bulk feature of the QGP such as transport coefficients and the QCD equations of states. In the quantitative analyses of the QGP property, high-precision numerical treatment on the hydrodynamic calculation is important. Recently, we developed a new 3+1 dimensional relativistic viscous hydrodynamics code in Cartesian coordinates. In the algorithm, we use a Riemann solver based on the two-shock approximation which is stable under existence of large shock waves. We extend the algorithm in Cartesian coordinates to that in Milne coordinates so that we can efficiently apply it to the analyses of relativistic heavy-ion collisions. We check the correctness of the numerical algorithm by comparing numerical calculations and analytical solutions in various problems for ideal and viscous fluids. The new numerical scheme is stable even with small numerical viscosity, which is very important to discuss the physical viscosities at RHIC and LHC.
209. Physics Colloquium
"From Stars to Nuclei and Back: Our Cosmic Origin and the Exascale Challenge to Find It"
Presented by Tony Mezzacappa, University of Tennessee
Tuesday, October 25, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: 'Peter Petreczky'
We learn in elementary school that the elements in the Periodic Table are the building blocks of our world, including our very bodies. But from where do the elements come? This is among the most basic questions we can ask, yet the precise answer remains elusive. We witness the cycle of life in our daily lives, everywhere on Earth. This is no less true in the Universe. With the exception of the lightest elements such as hydrogen and helium, elements are made in stars. As stars evolve and die, these elements pepper the interstellar medium, from which new stars, and planets, – in particular, our solar system – form. We understand the essential elements of this cycle – from stellar birth, life, and death, to the formation of the elements, to the formation of new stars and planets including those elements, to ultimately the origin of our solar system and life on Earth given those elements. But pieces of the puzzle are missing. We do not yet understand how certain stars that are factories for many of the elements, die, nor do we know the precise origin of half the elements heavier than iron, although we have narrowed down the list of possible sites. Today's colloquium will focus on the death of massive stars in catastrophic explosions known as core collapse supernovae. Such supernovae provide the lion's share of the elements between oxygen and iron, and are considered a potential site for the origin of half the elements heavier than iron. Arguably, they are the single most important source of elements in the Universe. Such supernovae present us with a general relativistic, radiation magneto-hydrodynamic – i.e., a multi-physics – environment to model. Further richness and complexity is added by the fact that the macroscopic evolution of such a system is governed in no small part by the high-density, neutron-rich, nuclear matter at the core of the supernova and by the microscopic interaction of radiation in the form of neutrinos with th
210. Nuclear Physics Seminar
"Recent Experimental Results on QCD Factorization Breaking of Nonperturbative Functions"
Presented by Joe Osborn
Tuesday, October 25, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Jin Huang'
In the last two decades the study of nucleon structure has shifted from a one-dimensional picture to exploring the dynamic three-dimensional structure of partons within the nucleon. In the transverse-momentum-dependent framework, nonperturbative parton distribution functions (PDFs) and fragmentation functions (FFs) explicitly carry dependence on partonic transverse momentum rather than only the collinear momentum of the parton with respect to the hadron or produced hadron with respect to the fragmenting parton. The recent interest in the transverse structure of the nucleon has largely been motivated by the novel phenomenological consequences that have been predicted for transverse-momentum-dependent nonperturbative functions. Contrary to the collinear framework, certain transverse-momentum-dependent PDFs are predicted to be process dependent. Additionally, factorization breaking has been predicted in hadronic collisions where a final-state hadron is measured and the observable is sensitive to nonperturbative transverse momentum. This prediction has the interesting quantum mechanical consequence that partons are correlated with each other across the bound state hadrons, rather than being identified with individual PDFs and FFs. Recent results from the PHENIX experiment at the Relativistic Heavy Ion Collider will be shown which investigate effects that are predicted to be sensitive to the nonperturbative factorization breaking.
211. Condensed-Matter Physics & Materials Science Seminar
"Creating Spatially Ordered States in Monolayer Graphene"
Presented by Abhay Pasupathy, Columbia University
Friday, October 21, 2016, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: 'Cedomir Petrovic'
Electrons in graphene at the Fermi level have chirality or handedness that arises from the honeycomb structure in real space. This chirality is responsible for many of the fascinating electronic properties of graphene such as Klein tunneling. In this talk, I will describe two related scanning tunneling microscopy experiments that probe the chiral nature of the electronic states in graphene. First, I will describe an experiment where we observe the chiral symmetry of graphene to be broken, resulting in a bond-ordered phase called Kekule order. I will show that this new phase in monolayer graphene can be induced by adatoms on the surface of graphene which interact electronically with each other. In a related experiment, I will describe the electronic structure of graphene in the presence of a circular potential well that separates the sheet into p (hole) and n (electron) doped regions. Electrons in these wells spend a finite amount of time before transitioning out of the well, resulting in quasibound states that can be measured in scanning tunneling spectroscopy. Due to the chirality of the electrons in graphene, the transition probabilities at the p-n junction are governed by the physics of Klein tunneling, which can be understood from the details of the energies and wavefunctions of the quasibound states observed in experiment.
212. Particle Physics Seminar
"Large area GEM detectors with zigzag readouts"
Presented by Aiwu Zhang, Florida Institute of Technology
Thursday, October 20, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
Gaseous Electron Multiplier (GEM) detectors have been widely studied and applied in many experiments. The so called zigzag readout has been studied for reading out large area GEM detectors for tracking purposes. Using of the zigzag readout can significantly reduce number of electronic channels and hence the cost of a detector while still preserving good spatial resolution on a detector. In this presentation, I will first briefly review the GEM detectors and their applications, then I will focus on the R&D activities on GEM detectors with zigzag readout for tracking at a future electron ion collider (EIC), I'll also cover some potential applications of large area GEM detectors and the zigzag readout for other experiments.
213. RIKEN Lunch Seminar
"Chiral magnetic effect and anomalous transport from real-time lattice simulations"
Presented by Niklas Mueller, Heidelberg University
Thursday, October 20, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: '''Hiroshi Oki'''
We present a first-principles study of anomaly induced transport phenomena by performing real-time lattice simulations with dynamical fermions coupled simultaneously to non-Abelian SU(Nc) and Abelian U(1) gauge fields. Investigating the behavior of vector and axial currents during a sphaleron transition in the presence of an external magnetic field, we demonstrate how the interplay of the chiral magnetic and chiral separation effect leads to the formation of a propagating wave. We further analyze the dependence of the magnitude of the induced vector current and the propagation of the wave on the amount of explicit chiral symmetry breaking due to finite quark masses. Further we perform simulations using overlap-fermions for the first time in real-time, showing that in the classical statistical regime they can be related to the Wilson formulation.
214. Nuclear Physics Seminar
"Phase diagram of the strongly interacting matter in an effective field theory approach"
Presented by Gyorgy Wolf
Tuesday, October 18, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Oleg Eyser'
In the framework of an SU(3) (axial)vector meson extended linear sigma model with additional constituent quarks and Polyakov loops, we investigate the effects of (axial)vector mesons on the chiral phase transition. The parameters of the Lagrangian are set at zero temperature and we use a hybrid approach where in the effective potential the constituent quarks are treated at one-loop level and all the mesons at tree-level. We have four order parameters, two scalar condensates and two Polyakov loop variables and their temperature and baryochemical potential dependence are determined from the corresponding field equations. We investigate the thermodynamics of the system, and at zero temperature we compare our results with lattice calculations. We calculate th phase diagram and the scalar meson masses in the hot and dense medium.
215. RIKEN Lunch Seminar
"Kibble-Zurek dynamics and universal off-equilibrium scaling of critical cumulants in the QCD phase diagram"
Presented by Raju Venugopalan, BNL
Thursday, October 13, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Hiroshi Oki''
We exploit the universality between the QCD critical point and the three dimensional Ising model to derive closed form expressions for non-equilibrium critical cumulants on the crossover side of the critical point. Novel expressions are obtained for the non-Gaussian Skewness and Kurtosis cumulants; our results reveal that they can differ both in magnitude and sign from equilibrium expectations. We show further that key elements of the Kibble-Zurek framework of non-equilibrium phase transitions can be employed to describe the dynamics of these critical cumulants. As a consequence, observables sensitive to critical dynamics in heavy-ion collisions are expressible as universal scaling functions and thereby provide powerful model independent guidance in searches for the QCD critical point.
216. HET/RIKEN Seminar
"Cannibal Dark Matter"
Presented by Marco Farina, Rutgers University
Wednesday, October 12, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: '''Pier Paolo Giardino'''
217. Nuclear Physics Seminar
"Transverse polarization of Lambda/anti-Lambda in e+e- annihilation at Belle and the K-Long muon (KLM) system of Belle-II detector"
Presented by Yinhui Guan, Indiana University
Tuesday, October 11, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Oleg Eyser'
Spontaneous Lambda polarization has been observed in unpolarized pp collisions years ago while the precise mechanism behind it remains unknown. It is assumed that the so called polarizing Fragmentation Function(FF) plays a important role in this effect. The polarizing FF is of great interest not only because it is strongly connected to the spin structure of hadrons, but also it is chiral-even and the sign is possible to be unambiguously measured so it provides a unique opportunity to test the universality of the FFs. The large e+e- annihilation data sample collected by the Belle experiment at the KEKB storage ring allows a precision study of the production of transversely polarized hyperons and check our current understanding of the associated QCD dynamics. The measurement of transverse Lambda/anti-Lambda polarization in e+e- annihilation in the inclusive Lambda production processes at Belle will be presented and discussed. The Belle II detector and SuperKEKB, the upgrade of Belle detector and KEKB collider, are being constructed at the KEK laboratory in Tsukuba, Japan. The K-Long and muon system of Belle II, which provides the K-Long and muon identification, consists of an alternating sandwich iron plates and active detector elements located outside of the superconducting solenoid. The Belle KLM based on glass-electrode resistive plate chambers(RPC) has demonstrated good performance. However, the long dead time of the RPCs during the recovery of the electric field after a discharge significantly reduces the detection efficiency under high backgrounds fluxes. So the endcap RPCs and two inner layers of barrel RPCs will be retired and replaced with scintillators in Belle II. This talk will introduce the Belle-II detector, mainly KLM system and the related offline software, KLM alignment and the current status of cosmic ray test (CRT).
218. Condensed-Matter Physics & Materials Science Seminar
"X-ray Imaging via Bragg CDI: From Ultrafast Physics to Defect Dynamics"
Presented by Andrew Ulvestad, Argonne National Laboratory
Friday, October 7, 2016, 11 am
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: ''Ian Robinson''
Bragg coherent diffractive imaging is an emerging x-ray imaging technique capable of resolving both defect and ultrafast dynamics in nanocrystals with three-dimensional detail and nanometer resolution. This ability to study single nanocrystals in their reactive environments opens new insight into a broad range of materials science questions, including how to improve materials that convert heat into electricity, understanding degradation in advanced battery cathodes, and probing the structure-stability relationship in fuel cell catalysts. Here I will discuss Bragg CDI studies of phonon dynamics in Zinc Oxide and defect dynamics in thin film grains driven by temperature. Finally, I will touch on future directions for BCDI with the anticipated increase in coherent flux at upgraded synchrotrons.
219. RIKEN Lunch Seminar
"Complex spectrum of QCD at finite density"
Presented by Hiromichi Nishimura, RBRC
Thursday, October 6, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Hiroshi Oki''
We consider the effective action of the Polyakov loop at finite temperature and density. Using simple models, we show two novel manifestations of the sign problem in QCD: the non-hermitian transfer matrix and the complex saddle point. As a result the mass matrix associated with the Polyakov loop becomes complex, and it gives rise to damped oscillatory behavior in Polyakov loop correlation functions, which reflects oscillatory behavior in the quark-number density reminiscent of density-density correlation functions in liquids. The complex spectrum should be observable in lattice simulations of QCD and may provide a test for finite-density algorithms.
220. Center for Functional Nanomaterials Seminar
"Reversed Nanoscale Kirkendall Effect in Au-InAs Hybrid Nanoparticles"
Presented by Anatoly I. Frenkel, Department of Materials Science and Engineering, Stony Brook University / Chemistry Department, Brookhaven National Laboratory
Thursday, October 6, 2016, 11 am
Bldg 735, Conference Room A
Hosted by: ''Eric Stach''
Metal-semiconductor hybrid nanoparticles (NPs) have synergistic properties that have been exploited in photocatalysis, electrical, and optoelectronic applications. Rational design of hybrid NPs requires the knowledge of the underlying mechanisms of diffusion of the metal species through the nanoscale semiconductor lattice. One extensively studied process of diffusion of two materials across the nanoparticle surface is known as the nanoscale Kirkendall effect. There, an atomic species A with the lower diffusion rate enters the nanocrystal slower than the B species diffusing from the nanocrystal outward. As a result, voids are formed in B, providing an interesting avenue for making hollow nanocrystals. We used time-resolved X-ray absorption fine-structure spectroscopy, X-ray diffraction and electron microscopy to monitor the diffusion process of Au atoms through InAs nanocrystals in real time. In this system the diffusion rate of the inward diffusing species (Au) is faster than that of the outward diffusion species (InAs), which results in the formation of a crystalline metallic Au core surrounded by an amorphous, oxidized InAs shell with voids in it. These observations indicate that in hybrid Au-InAs NPs the rarely observed "reversed nanoscale Kirkendall effect" is in play. It presents a potentially new way to synthesize unique nanoscale core-shell structures.
221. Particle Physics Seminar
"Dark Interactions: perspective from theory and experiment"
Thursday, October 6, 2016, 9 am
Small Seminar Room, Bldg. 510
Hosted by: 'Michael Begel'
222. Condensed-Matter Physics & Materials Science Seminar
"The numerical renormalization group as a viable multi-band impurity solver for dynamical mean-field theory"
Presented by Katharina Stadler, Ludwig-Maximilians-Universitaet Muenchen, ASC, Germany
Wednesday, October 5, 2016, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: 'Gabi Kotliar'
In my talk I will present the numerical renormalization group (NRG) as a viable multi-band impurity solver for dynamical mean-field theory (DMFT). NRG offers unprecedented real-frequency spectral resolution at arbitrarily low energies and temperatures. It is thus perfectly suited to study "Hund metals" [1], which show - in experiments and theoretical DMFT calculations - puzzling behavior at unusually low energy scales, like Fermi-liquid behavior at low temperatures, a coherence-incoherence crossover with increasing temperature [2, 3] and fractional power laws for the imaginary part of the Matsubara self-energy in the incoherent regime, discovered already early on with continuous time quantum Monte Carlo (CTQMC) as DMFT solver [3]. I will explicitly demonstrate the advantages of NRG+DMFT in the context of a channel-symmetric three-band Anderson-Hund model on a Bethe lattice at 1/3 filling (with NRG exploiting the non-abelian SU(3) channel symmetry to reduce numerical costs) [4]. In contrast to CTQMC, our NRG+DMFT calculations finally settled the existence of a Fermi-liquid ground state. We further revealed new important insights: our real-frequency one-particle spectral function shows a coherence-incoherence crossover (driven by Hund J rather than Hubbard U) and strong particle-hole asymmetry, which leads to the above-mentioned apparent fractional power laws; two-stage screening, where spin screening occurs at much lower energies than orbital screening ("spin-orbital separation"); and zero-temperature spectral properties that are similar with or without DMFT self-consistency, in contrast to Mott-Hubbard systems, where the DMFT self-consistency opens a gap. A recent reformulation of NRG, called "interleaved NRG" (iNRG) [5, 6] allows to tackle more realistic models of Hund metals where channel symmetries are generally broken (for example, due to crystal field splitting).
223. Nuclear Physics Seminar
"EoSization in holgraphic shockwave collision"
Presented by Maximilian Attems, University of Barcelona
Tuesday, October 4, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Oleg Eyser'
Ever since fast hydrodynamization has been observed in heavy ion collisions the understanding of the very early non-equilbrium stage of such collisions has been a topic of intense research. We use the gauge/string duality to model the creation of a strongly coupled Quark-Gluon plasma in a non-conformal gauge theory. This study is the first non-conformal holographic simulation of a heavy ion collision. We extract new physics as compared to the conformal case such as the non-trivial equation of state and the presence of a sizeable bulk viscosity. Non-conformality gives rise to an increase of the relaxation times of the resulting plasma. Furthermore, if the bulk viscosity is large enough then the plasma becomes well described by hydrodynamics before the equilibrium equation of state becomes applicable. This time we refer to as the EoSization time. This EoSization process is a new non-conformal relaxation channel involving the evolution of energy density and average pressure. It is exciting to see this new channel for bulk viscsosity values well below QCD critical temperature estimates.
224. Environmental & Climate Sciences Department Seminar
"Viscous organic aerosol particles and water uptake: From observations of internal diffusion fronts in single, levitated particles to estimating kinetic limitations under atmospheric conditions"
Presented by Dr. Ulrich Krieger, Institut für Atmosphäre und Klima, Zürich, Switzerland
Friday, September 30, 2016, 11 am
Conference Room Bldg 815E
Hosted by: 'Robert McGraw'
Field measurements in the recent past have shown that secondary organic aerosol (SOA) particles are often amorphous glasses or highly viscous liquids under dry and/or cold conditions. Chemical and physical processes occurring in the interior of the aerosol particle and at the gas/particle interface are influenced by the viscous state in which condensed-phase diffusion is slows down considerably. I will discuss measurements of water diffusion in single, levitated aerosol particles for a number of model systems of SOA. In particular, I will show how Mie-resonance spectroscopy allows to "image" diffusion fronts within these particles and discuss atmospheric implications of kinetic limitations of water uptake.
225. Particle Physics Seminar
"Sterile Neutrino Search at Daya Bay"
Presented by Dr. Wei Tang, BNL
Friday, September 30, 2016, 10 am
Small Seminar Room, Bldg. 510
Hosted by: ''Xin Qian''
Daya Bay recently updated the light sterile neutrino searching results with 621 days of data. The new analysis has 3.6 times of statistics, improved energy calibration as well as the reduced backgrounds compared to the previous publication. The resulting limits on sin22theta14 are improved by approximately a factor of two over previous results and constitute the most stringent constraints to date in the Delta m2_41 < 0.2 eV2 region. The result is combined with those from MINOS and Bugey-3 experiments to constrain oscillation into light sterile neutrinos. The three experiments are sensitive to complementary regions of parameter space, enabling the combined analysis to probe regions allowed by the LSND and MiniBooNE experiments in 3+1 neutrino framework. Stringent limits on sin22theta_mue are set over six orders of magnitude in the sterile mass-squared splitting Delta m2_41. In this talk, I will show details of the recent update sterile neutrino search at Daya Bay, the reproduction of Bugey-3's results and the combination of Daya Bay, Bugey-3 and MINOS results.
226. Particle Physics Seminar
"Simulating the large-scale structure in different density environments"
Presented by Chi-Ting Chiang, Stony Brook University
Thursday, September 29, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: '''Anze Slosar'''
Understanding structure formation is one of the most important issues in modern cosmology. In particular, in the era of big astronomical data, connecting observation and theory is crucial to improve precision cosmology, and possibly probe new physics. The observables of large-scale structure, such as galaxy number density, generally depend on the density of the environment. This dependence can traditionally be studied by performing gigantic cosmological N-body simulations and measuring the observables in different density environments. Alternatively, we can perform so-called separate universe simulations,'' in which the effect of the environment is absorbed into the change of the cosmological parameters. In other words, an overdense universe is equivalent to a positively curved universe, and the structure formation would change accordingly. In this talk, I will introduce the separate universe mapping, and present how the power spectrum and halo mass function changes in different density environments, which are related to the squeezed-limit bispectrum and the halo bias, respectively. I will also discuss our recent progress on extending this approach to multiple fluids such as dynamic dark energy and massive neutrinos.
227. Particle Physics Seminar
"Measurement of muon g-2 and EDM with ultra-cold muon beam at J-PARC"
Presented by Dr. Tsutomu Mibe, KEK
Thursday, September 29, 2016, 10 am
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
The J-PARC E34 experiment aims to measure the anomalous magnetic moment (g-2) and electric dipole moment (EDM) of the positive muon with a novel technique utilizing an ultra-cold muons accelerated to 300 MeV/c and a 66 cm-diameter compact muon storage ring without focusing electric field. This measurement will be complementary to the previous BNL E821 experiment and upcoming FNAL E989 experiment with the muon beam at the magic momentum 3.1GeV/c in a 14 m-diameter storage ring. In this talk, I'd like to discuss the present status and prospects.
228. HET Seminar
"Lattice QCD for Neutrino Physics"
Presented by Aaron Meyer, University of Chicago
Wednesday, September 28, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Mattia Bruno'
229. Physics Colloquium
"Synthetic gene circuits: New research tools for quantitative biology"
Presented by Gabor Balazsi, Stony Brook U
Tuesday, September 27, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: 'Peter Petreczky'
Synthetic biology is a new interdisciplinary field that designs and builds artificial biological systems, using principles from physics, engineering, and mathematics. Recent success stories include the massive, low-cost synthesis of the anti-malaria drug artemisinin, and the construction of genetic switches, oscillators and logic gates. In my laboratory we build synthetic gene circuits and use them as new research tools to precisely perturb cells and watch how they respond. This way, we hope to develop a predictive, quantitative understanding of biological processes such as microbial drug resistance and cancer. We have developed an expanding library of synthetic gene regulatory circuits first in yeast, and then in cancer cells for this purpose. I will illustrate through a few examples how we can gain a deeper, quantitative understanding of microbial drug resistance and cancer using synthetic gene circuits.
230. Particle Physics Seminar
"SB/BNL Joint Cosmo Seminar"
Thursday, September 22, 2016, 12 pm
Stony Brook
Hosted by: 'Anze Slosar'
231. Joint YITP/HET Seminar
"Towards precision jet physics at the LHC"
Presented by Matt Schwartz, Harvard
Wednesday, September 21, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Amarjit Soni''
232. Nuclear Physics Seminar
Presented by Charlotte Van Hulse, University of the Basque Country
Tuesday, September 20, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Oleg Eyser'
233. Condensed-Matter Physics & Materials Science Seminar
"Interplay of structure, magnetism and superconductivity in the 112 Fe based superconducting family"
Presented by Ni Ni, UCLA
Thursday, September 15, 2016, 1:30 pm
Seminar Room, 2nd Fl, ISB Bldg. 734
Hosted by: ''Robert Konik''
Both cuprates and Fe-based superconductors, the two known high Tc superconducting families, show rich emergent phenomena near the superconductivity (SC). To understand the mechanism of unconventional SC, it is crucial to unravel the nature of these emergent orders. The 112 Fe pnictide superconductor (FPS), Ca1−xRExFeAs2 (CaRE112), shows SC up to 42 K, the highest bulk Tc among all nonoxide FPS. Being an exceptional FPS where the global C4 rotational symmetry is broken even at room temperature, it is important to extract the similarities and di?erences between 112 and other FPS so that critical ingredients in inducing SC in FPS can be ?ltered. In this talk, I will review current progress in the study of 112. The comparison between Co doped CaLa112 and Co doped 10-3-8 will be made and the importance of interlayer coupling will be discussed.
234. RIKEN Lunch Seminar
"Quark Polarization at Small x"
Presented by Matt Sievert, BNL
Thursday, September 15, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Hiroshi Oki''
Parton distribution functions in the small-x limit have long been known to be dominated by gluon bremsstrahlung produced in the BFKL and BK / JIMWLK evolution mechanisms. This small-x gluon cascade generates high color-charge densities, leading to the effective semi-classical theory known as the color-glass condensate (CGC). While this unpolarized small-x evolution has been thoroughly studied, the evolution of the polarized parton distributions is much less understood. Using modern CGC techniques, we calculate the small-x evolution equations for the helicity distribution of polarized quarks. This polarized small-x evolution is quite different from the unpolarized evolution, bringing in much more complicated dynamics which transfer spin to small x. Although the quark polarization at small x is initially suppressed, strong evolution corrections substantially enhance the amount of spin at small x. By solving our equations (numerically, in the large-Nc limit), we compute the asymptotic behavior of the quark helicity at small x, and we discuss the implications of this result for the outstanding Proton Spin Puzzle.
235. Physics Colloquium
"Transport in QCD: A Theorist's View"
Presented by Guy Moore, University of Darmstadt
Tuesday, September 13, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: ''Robert Pisarski''
After summarizing the role of hydrodynamics in QCD and heavy ion physics, I will focus on what we know, theoretically, about the transport coefficients which enter hydrodynamics. I will focus on shear viscosity and heavy quark diffusion. I will explain the problems and limitations of the theoretical tools we have, and how we hope to push them a little farther — and better characterize their weaknesses.
236. Nuclear Physics Seminar
"Finite-Size Scaling of Susceptibility and Non-Gaussian Fluctuations Near the QCD Critical Point"
Presented by Roy Lacey, Stony Brook University
Friday, September 9, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Matthew Sievert'
A major experimental theme at the Relativistic Heavy Ion Collider (RHIC), is the the study of observables that could signal the location and character of the critical endpoint (CEP) – the end point of the first-order coexistence curve in the temperature vs. baryon chemical potential (T, μB) plane of the phase diagram for Quantum Chromodynamics (QCD). I will show that Finite-Size Scaling of measurements linked to both the susceptibility and critical fluctuations, lead to scaling functions which provide a potent tool for locating and characterizing the CEP. A recent estimate of the location of the CEP and the associated critical exponents used to assign the order of the transition and its universality class will be presented as well.
237. HET Lunch Discussions
"The Beryllium anomaly and a possible particle physics interpretation"
Presented by Eder Izaguirre, BNL
Friday, September 9, 2016, 12:15 pm
Building 510, Room 2-160
Hosted by: 'Christoph Lehner'
238. Nuclear Physics Seminar
"Current state of nPDFs, LHC and future possibilities"
Presented by Pia Zurita, Universidade de Santiago de Compostela, Spain, Spain
Thursday, September 1, 2016, 2 pm
2-160
Hosted by: 'Thomas Ullrich'
In the last years, significant progress has been made in obtaining nuclear PDFs (nPDFs) from data. In addition to the theoretical improvements routinely used in modern extractions of free proton PDFs, the most recent determinations of nPDFs have move towards truly global QCD analyses of nuclear effects. Furthermore, the end of the Run at the LHC I has shown promising results for the improvement of our knowledge on the nuclear medium. In this talk I will discuss the current state of nPDFs, comparing the most recent determinations, and address the possible impact of LHC and future colliders' data on the nPDFs.
239. Condensed-Matter Physics & Materials Science Seminar
"The first-principles study of structural, electronic, and magnetic properties of strongly correlated materials: DFT+DMFT approach."
Presented by Hyowon Park, University of Illinois
Thursday, August 25, 2016, 3 pm
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: ''Neil Robinson''
Strongly correlated materials including transitional metal oxides and heavy fermion materials exhibit novel structural, electronic, and magnetic properties. The first-principles study of these unusual properties requires a theoretical description that goes beyond density functional theory to treat strong correlation effects properly. In this talk, I will show that the density functional theory plus dynamical mean field theory (DFT+DMFT) method enables realistic and quantitative calculations of those properties in good agreement with experimental spectroscopic measurements. First, I will clarify the nature of the insulating phase in bulk rare-earth nickelates using DFT+DMFT and determine the structural and metal-insulator phase diagram. I will also present DFT+DMFT results of structural and electronic properties in artificially structured LaNiO3/LaAlO3 superlattices under strains. Calculation results of layer-resolved orbital polarization will be compared to recent X-ray absorption spectroscopy data and analyzed in terms of structural and quantum confinement effects. Finally, I will show the momentum and frequency dependent magnetic excitation spectra in CePd3 computed using DFT+DMFT and explain that the calculated spectra based on realistic band excitations are in good agreement with the inelastic neutron scattering data measured in this material.
240. Particle Physics Seminar
"Testing the Standard Model with the lepton g-2"
Presented by Massimo Passera, INFN
Thursday, August 25, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: ''William Marciano''
241. Nuclear Physics Seminar
"Multiplicity Fluctuations in Dilute-Dense Scattering"
Presented by A. H. Mueller, Columbia University
Friday, August 19, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Matthew Sievert'
The general features of the event-by-event fluctuations of the multiplicity of gluons produced in the scattering of a dilute "hadron" off a large nucleus are discussed. Analytic calculations are possible in "semi-realistic" circumstances.
242. Condensed-Matter Physics & Materials Science Seminar
"Controlling the metal-insulator transition in LaNiO3"
Presented by Frederick Walker, Yale University
Thursday, August 18, 2016, 1:30 pm
Bldg. 734, ISB Bldg., Conf Room 201 (upstairs)
Hosted by: 'Mark Dean'
New materials are needed to advance electronic, optical and energy materials beyond current technology trends. Perovskite oxides can potentially meet these needs due to their flexibility and unique functional properties. In bulk materials, these properties are accessed through modifications of physical and electronic structure through cation substitution in the perovskite lattice. An even larger phase space of properties and functionalities is possible when these materials are combined in thin film heterostructure form using molecular beam epitaxy. The sensitivity of the resulting properties on interface structure often dominates device function. Uncovering a microscopic understanding of emergent properties at such interfaces is challenging due to the small volume of material present. In this talk, we show how a combination of first principles theory and experiment can be used to develop a non-volatile, three terminal switch. The device is implemented by using the perovskite LaNiO3 as a conducting channel and a ferroelectric gate. The approach to developing this switch involves synchrotron x-ray characterization of picoscale structural distortions for LaNiO3 heterostructures, including LaNiO3-vacuum, LaNiO3-band insulator, and LaNiO3-ferroelectric. The consequences of the picoscale distortions are strong modulations of the measured electronic transport as a function of interface and ferroelectric polarization direction. Quantitative comparisons of the structure with first principles theory show excellent agreement. Theory provides an understanding of how the picoscale distortions at the interface result in changes in orbital occupation and band properties of both the nickelate and ferroelectric. These insights inspire new principles for designing ferroelectric heterostructures that show record non-volatile resistance modulations.
243. HET/RIKEN Seminar
"Standard Model Vacuum Stability with a 125 GeV Higgs Boson"
Presented by Stefano Di Vita, DESY
Friday, August 12, 2016, 12:15 pm
Building 510, Room 2-160
Hosted by: ''Pier Paolo Giardino''
244. Special Nuclear Theory Seminar
"Scalar mesons in low-energy QCD and probing their properties within generalized linear sigma model"
Presented by Amir Fariborz, SUNY Institute of Technology at Utica
Tuesday, August 9, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Rob Pisarski'
Unlike the light pseudoscalar mesons, understanding the properties of light scalar mesons (particularly, their quark substructure) is known to be quite nontrivial. Scalar mesons are important from the theoretical point of view because they are effectively the Higgs bosons of QCD and induce chiral symmetry breaking, and therefore, are probes of the QCD vacuum. Scalars are also important from a phenomenological point of view, as they are crucial intermediate states in Goldstone boson interactions away from threshold; in a range of energy that is too high for a chiral perturbation theory framework, and too low in the context of the perturbative QCD. The physics of scalar mesons has a great impact on our understanding of important issues in strong interactions such as the diquarks, glueballs, hybrids, violation of isospin, low energy hadron phenomenology, instantons, and final-state interaction of pseudoscalar mesons. Moreover, physics of scalar mesons can provide significant insights outside its immediate focus of low-energy QCD such as, for example, in studies of decay Ds to f0(980) e+ ve or decay Bs to J/psi f0(980) measured by LHCb. In this talk, the status of the scalar mesons will be briefly reviewed and the generalized linear sigma model of low-energy QCD for understanding their properties will be presented. Specifically, the underlying symmetries (and their breakdown) for designing the generalized linear sigma model, as well as various contacts with experiment for fixing the free paremeters of the model will be discussed in some details. Several predictions for various low-energy processes as well as the application of this model to studies of heavier meson decays will be given, and directions for further extensions of the model will be discussed.
245. Nuclear Physics Seminar
"Polarization phenomena in the Drell-Yan process"
Presented by Werner Vogelsang, University of Tübingen
Friday, August 5, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Matthew Sievert'
We present calculations of next-to-leading order corrections to the cross section and the single-longitudinal spin asymmetry for W boson production at RHIC. We also discuss decay lepton angular distributions in the Drell-Yan process at hadron colliders and in fixed-target experiments.
246. Particle Physics Seminar
"Study of the detection of supernova neutrinos"
Presented by Hanyu Wei, Tsinghua University
Friday, August 5, 2016, 10 am
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
A core-collapse supernova explosion would release an enormous amount of neutrinos, the detection of which could yield answers to many questions of supernova dynamics and neutrino physics. The collective neutrinos from all the past supernovae all over the universe (supernova relic neutrinos) are also observable, and their detection would provide us an insight of the stellar evolution and cosmology. In this talk, I will first introduce the supernova burst neutrinos as well as supernova relic neutrinos. Then, i will present the design, characteristics, and sensitivity of an online trigger system of supernova burst neutrinos at Daya Bay. I will also present a search for supernova burst neutrinos at Daya Bay using about 600 days of data. At last, a sensitivity study of the discovery potential for supernova relic neutrinos with a slow liquid scintillator will be presented, which is highly recommended to kilo-ton-scale detectors.
247. Particle Physics Seminar
"KamLAND-Zen and NuDot: The Future of Liquid Scintillator Detectors"
Presented by Lindley Winslow, MIT
Thursday, August 4, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Xin Qian''
Large liquid-scintillator-based detectors have proven to be exceptionally effective for low energy neutrino measurements due to their good energy resolution and scalability to large volumes. The addition of directional information using Cherenkov light and fast timing would enhance the scientific reach of these detectors, especially for searches for neutrino-less double-beta decay. NuDot is a 1m3 prototype detector that will demonstrate this technique using fast photodetectors and eventually quantum-dot doped liquid scintillator. The ultimate goal is a measurement of two neutrino double-beta decay with direction reconstruction.
248. RIKEN Lunch Seminar
"Photon-jet Ridge at RHIC and the LHC"
Presented by Amir Rezaeian, The Federico Santa Maria Technical University
Thursday, August 4, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Hiroshi Oki''
I will talk about inclusive prompt photon and photon-jet production in p+A collisions at RHIC and the LHC. In particular, I show that photon-jet correlations in the Color Glass Condensate (CGC) picture exhibit long-range azimuthal collimation at near-side for low transverse momenta of the produced photon and jet in high-multiplicity events. These ridge-like features are strikingly similar to the observed ridge effect for di-hadron correlations at RHIC and the LHC. I show that correlations in the relative rapidity and the relative azimuthal angle between pairs of prompt photon and jet strongly depend on the gluon saturation dynamics at small-x kinematics and such measurements can help to understand the true origin of the observed di-hadron ridge in p+A collisions, and address whether the ridge is a universal phenomenon for all two particle correlations at high energy and high multiplicity events.
249. Center for Functional Nanomaterials Seminar
"Perovskite Photovoltaics and g-ray Radiation Detectors Research Highlights"
Presented by Deidra R. Hodges, Ph.D., University of Texas at El Paso
Wednesday, August 3, 2016, 11 am
CFN, Bldg 735, Conference Room A, 1st Floor
Hosted by: '''''Mircea Cotlet'''''
Perovskite Photovoltaics: Renewable energies are one of the most important components of the global new energy strategy. Utilizing the power of the sun is one of the most viable ways to solve the foreseeable world's energy crisis. With increasing attention toward carbon-neutral energy production, solar electricity, or photovoltaic (PV) technology, is the object of steadily growing interest. The International Energy Agency's technology roadmap estimates that by 2050, PV will provide ~ 11% of all global electricity production & avoid 2.3 gigatonnes of CO2 emissions per year. A new solar cell material has evolved with transformative potential with laboratory efficiencies of 19.7%. Perovskite absorber materials are very inexpensive to synthesize & simple to manufacture, making them an extremely commercially viable option. Solar cell efficiencies of devices using these materials have increased from 3.8% in 2009 to a certified 20.1% in 2015, making this the fastest-advancing solar cell technology to date. These devices are also known for their high photon absorptivity, ideal direct band gaps with superior carrier charge transports, & cost-effective modes of fabrication scalability. Gama-ray Radiation Detectors: Cadmium zinc telluride (Cd1-xZnxTe or CZT), a ternary semiconductor material is well suited for good charge collection efficiency & high energy resolution room temperature x- & gamma (γ) -ray radiation detectors. In addition, these detectors can be small in size & have fast timing characteristics. Key semiconductor material properties required for high efficiency, & high energy resolution radiation detectors operable at room temperature are a high atomic number, ideal bandgap & low leakage current, high carrier mobility-lifetime (µτ) product to ensure complete charge collection, & high-purity, homogenous, & defect-free. CZT is recognized as one of the leading materials for fabrication.
250. Nuclear Physics Seminar
"Azimuthal anisotropy and the distribution of linearly polarized gluons in DIS dijet production at high energy"
Presented by Adrian Dumitru, Baruch College
Friday, July 29, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Matthew Sievert'
High Pt Dijet production in ep/eA DIS at small x (high energy) involves the expectation value of a trace of four Wilson lines, i.e. the quadrupole. At leading power the isotropic part can be expressed as the conventional Weizsacker-Williams gluon distribution. On the other hand, the distribution of linearly polarized gluons determines the amplitude of the ~ cos(2phi) anisotropy of the transverse momentum imbalance. I shall also discuss the operator that determines the next-to-leading power correction, its expectation value in a Gaussian theory (at large Nc), and the resulting .
251. Particle Physics Seminar
"Modeling electron- and neutrino-nucleus scattering in kinematics"
Presented by Vishvas Pandey, Ghent University
Thursday, July 28, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Thomas Ullrich''
The accelerator-based neutrino-oscillation program, aimed for the measurement of oscillation parameters and observing the leptonic CP violation, is moving full steam ahead. However, the recent measurements have revealed unexpected and interesting neutrino interaction physics, and exposed the inadequacy of the relativistic Fermi gas (RFG) based Monte-Carlo generators (in describing neutrino-nucleus scatterings) resulting in large systematic uncertainties. A more detailed and careful neutrino-nucleus modeling, covering the whole experimental kinematical space, is inevitable in order to achieve the unprecedented precision goal of the present and future accelerator-based neutrino-oscillation experiments. In this talk, I will present a microscopic Hartree-Fock (HF) and continuum random phase approximation (CRPA) approach to electroweak scattering off nuclei from low energy (threshold) to the intermediate energy region. As a necessary check to test the reliability of this approach, I will first present a electron-nucleus (^12 C, ^16 O, ^40 Ca) cross section comparison (in the kinematics range of interest) with the data to validate the model. Then, I will present flux-folded (anti)neutrino cross section calculations and comparison with the measurements of MiniBooNE and T2K experiments. I will draw special attention to the contribution emerging from the low-energy nuclear excitations, at the most forward scattering bins, in the signal of MiniBooNE and T2K experiments and their impact on the non-trivial differences between muon-neutrino and electron-neutrino cross sections. These effects remain inaccessible in the (current) relativistic Fermi-gas (RFG) based Monte-Carlo generators.
252. Nuclear Physics Seminar
"Transport Functions from Fluid/Gravity Correspondence"
Presented by Michael Lublinsky, Ben-Gurion University
Friday, July 22, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Matthew Sievert'
Transport coefficients in two systems are addressed via holographic methods originating from the AdS/CFT. The first system is a neutral conformal fluid. In linearised hydrodynamics, beyond shear viscosity, all order gradient expansion can be efficiently resummed into two momenta-dependent transport coefficient functions. The second system is an e/m current coupled via chiral anomaly to an axial U(1) current. The anomaly-free all order transport coefficients are resummed into three momenta-dependent functions, the diffusion function and two conductivities. Anomaly-induced transport, resummed to all orders, generalises the chiral-magnetic effect (CME) and related phenomena. Novel, anomaly-induced non-linear effects will be presented too.
253. Particle Physics Seminar
"Results from the Search for eV-Sterile Neutrinos with IceCube"
Presented by Dr. Carlos Arguelless Delgado, Massachusetts Institute of Technology
Thursday, July 21, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Xin Qian''
The IceCube neutrino telescope at the South Pole has measured the atmospheric muon neutrino spectrum as a function of zenith angle and energy. Using IceCube's full detector configuration we have performed a search for eV-scale sterile neutrinos. Such a sterile neutrino, motivated by the anomalies in short-baseline experiments, is expected to have a significant effect on the $\bar{\nu_\mu}$ survival probability due to matter induced resonant effects for energies of order 1 TeV. This effect makes this search unique and sensitive to small sterile mixings. In this talk, I will present the results of the IceCube sterile neutrino search.
254. NSLS-II Friday Lunchtime Seminar Series
"Effect of Hydrophobic and Hydrophilic Silica Nano Particles on the Dynamics of Phospholipid Films, an XPCS Investigation"
Presented by Luigi Cristofolini, University of Parma, Italy
Friday, July 15, 2016, 12 pm
NSLS-II Bldg 744 (LOB 4), room 156
Hosted by: 'L. Carr, S. Chodankar and B. Ocko'
255. Particle Physics Seminar
"MicroBooNE: marking a Nu era in Precision Neutrino Physics"
Presented by Dr. Sowjanya Gollapinni, KSU
Friday, July 15, 2016, 10 am
Small Seminar Room, Bldg. 510
Hosted by: 'Jyoti Joshi'
The past few years have brought several remarkable neutrino-related discoveries and experimental anomalies indicating that these elusive particles might hold clues to some of the most profound questions in particle physics such as matter-antimatter asymmetry and the possibility of additional low-mass neutrino states. Further exploration of these clues require technological advances in neutrino detection. Liquid Argon Time Projection Chambers (LArTPCs) are imaging detectors that present neutrino interactions with the detail of bubble chambers, but with an electronic data acquisition and processing. Various efforts are ongoing at Fermi National Accelerator Laboratory (Fermilab) to develop this intriguing technology. MicroBooNE is a 170 ton LArTPC which recently started collecting data with Fermilab's Booster Neutrino Beam. In addition to addressing the recent low-energy electromagnetic anomaly observed by the MiniBooNE experiment, the exceptional particle identification capability of MicroBooNE will make it possible for the first time to measure low-energy (~1 GeV) neutrino cross-sections in argon with high precision thereby providing invaluable inputs to develop nuclear models needed for future long-baseline neutrino oscillation experiments. MicroBooNE is also leading the way for an extensive short-baseline neutrino physics program at Fermilab and also serves as a R&D project towards a long-baseline multi-kiloton scale LArTPC detector. This talk will start by giving a brief overview of LArTPC efforts at Fermilab, followed by a description of the MicroBooNE experiment, its current status and first physics results along with some future projections.
256. Particle Physics Seminar
"Physics with Taus at ATLAS"
Presented by Sarah Demers
Thursday, July 14, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: '''Michael Begel'''
Tau leptons are notoriously difficult particles to work with in the environment of a hadron collider due to their short lifetime and heavy enough mass for semi-hadronic decay. In this talk I will present the physics motivation for working with taus in spite of the challenges. And I will describe the work my group is involved with, from the first measurement of tau polarization at a hadron collider, to Higgs-tagging and searches for heavy, exotic particles. I will also describe the landscape for physics with taus at ATLAS as we look into Run2 and beyond.
257. RIKEN Lunch Seminar
"CME in Chiral Viscous Hydrodynamics"
Presented by Shuzhe Shi, Indiana University
Thursday, July 14, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Hiroshi Ohki'
Anomalous chiral transport processes, with the notable examples of Chiral Magnetic Effect (CME) and Chiral Magnetic Wave (CMW), are remarkable phenomena that stem from highly nontrivial interplay of QCD chiral symmetry, axial anomaly, and gluonic topology. The heavy ion collisions, in which topological fluctuations generate chirality imbalance, and very strong magnetic fields $|\vec{\bf B}|\sim m_\pi^2$ are present during the early stage of such collisions, provide a unique environment to study these anomalous chiral transport processes. Significant experimental efforts have been made to look for signals of CME and various other signals of anomalous chiral transport effects in heavy ion collisions. Crucial for such efforts, is the theoretical development of quantitative simulations based on hydrodynamics that incorporates chiral anomaly, implements realistic initial conditions and properly accounts for possible backgrounds. We will introduce our recent progress to understand CME qualitatively, based on a 2+1D viscous hydrodynamics framework
258. Nuclear Physics Seminar
"Modeling chiral criticality and its consequences for heavy-ion collisions"
Presented by Gabor Almasi, GSI
Friday, July 8, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Matthew Sievert'
Fluctuations of conserved charges are important observables that offer insight into the phase structure of strongly interacting matter. Around critical points, such as the chiral critical endpoint of QCD, higher order cumulants of the relevant quantities show universal behavior. The universal behavior of baryon number cumulants can be studied in effective models that lie in the same universality class as QCD. Such a model is for example the Quark Meson model. In my talk I discuss what one can learn from effective field theory studies of fluctuations and present my results obtained using the Functional Renormalization Group method in the Quark Meson model.
259. Particle Physics Seminar
"Dark Matter in the Cosmos-The Hunt to find it in the Laboratory"
Thursday, July 7, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Michael Begel'
Matter constitutes 30% of the energy content of the Universe. The remaining 70% is what is called dark energy, which exhibits unusual repulsive gravitational interactions. On the matter sheet, only 5% is of known nature, i.e. matter such as found in atoms, in stars, in planets etc. From observations on all astrophysical and cosmological scales we know that most of it, i.e. 25%, is dark matter (DM) of unknown nature. The nature of DM is one of the most important open problems in science. The ongoing hunt for DM is multi-pronged and interdisciplinary involving cosmology and astrophysics, particle and nuclear physics as well as detector technology. In this talk we will focus on the direct detection of the dark matter constituents, the so called weakly interacting massive particles (WIMPs), in underground labs. The detection consists of measuring the energy deposited in the detector by the recoiling nucleus, after its elastic collision with a WIMP (spin independent or spin induced). In obtaining the event rates one needs models about the WIMP interaction and density in our vicinity as well as its velocity distribution. No events have so far been observed, only exclusion plots on the nucleon cross sections have been obtained, which will be discussed. Since the expected rates are very small and the usual experimental signature is not different from that of the backgrounds, we will discuss some special signatures that might aid in the analysis of the experiments such as the time dependence of the signal (modulation effect) and the option of inelastic scattering, possible in some special targets, by detecting γ-rays following the de-excitation of the nucleus.
260. RIKEN Lunch Seminar
"Kondo effect in QCD"
Presented by Sho Ozaki, Keio University
Thursday, June 30, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Hiroshi Oki''
In condensed matter physics, Kondo effect is known as an enhancement of electrical resistance of impure metals with decreasing temperature/energy. This phenomenon is the first known example of asymptotic freedom in physics, which is found well before the discovery of that of QCD. Kondo effect is caused by the combination of the following ingredients: In addition to the existence of a heavy impurity, (i) Fermi surface, (ii) quantum fluctuations (loop effects), (iii) non-Abelian nature of interaction (e.g. spin-flip interaction in the case of condensed matter physics). In this talk, I will discuss Kondo effect realized in QCD. We found the characteristic behavior of Kondo effect in quark matter with heavy quark impurity. There, the color exchange interaction mediated by gluons plays the role of the third condition (iii) for the appearance of Kondo effect. Furthermore, we found a novel type of Kondo effect induced by strong magnetic fields. In addition to the fact that the magnetic field dose not affect the color degrees of freedom, dimensional reduction to 1+1 dimensions and degenerate quarks in lowest Landau level play essential role for the magnetically induced QCD Kondo effect.
261. Physics Colloquium
"Solving the World's Problems on the Back of a Cocktail Napkin"
Presented by Lawrence Weinstein, Old Dominion University
Tuesday, June 28, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: ''''Robert Pisarski''''
Why don't we all drive electric cars? Does it really matter if you don't recycle that plastic water bottle? If the Sun were made of gerbils, would the Earth be incinerated? How can we answer these questions without relying on experts? This talk will cover the principles of estimating, introduce the "Goldilocks" categories of answers, and then look at some of the big (and small) questions of our time, including: Paper or plastic? Gasoline or electric cars? Should we pee before flying?
262. Nuclear Physics Seminar
"Two Photon Exchange and the Proton Form Factor Problem"
Presented by Lawrence Weinstein, Old Dominion University
Tuesday, June 28, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Oleg Eyser'
The electromagnetic form factors of the proton as measured by polarized and unpolarized electron scattering experiments differ by up to a factor of three at large momentum transfer. Calculations show that this discrepancy can be reconciled by treating the interaction in 2nd Born Approximation, i.e., including two photon exchange (TPE). While calculation of TPE effects is highly model dependent, these effects can be measured directly by comparing elastic electron-proton and positron-proton scattering. Three experiments, TPE at Jefferson Lab, VEPP-3 at Novosibirsk, and OLYMPUS at DESY, measured this. VEPP-3 and OLYMPUS used alternating monochromatic e+ and e- beams in storage rings; TPE created a tertiary mixed simultaneous e+/e- beam covering a wide range of energies. This talk will present the proton form factor problem, the experimental effort to measure the positron-electron ratio (with special emphasis on the Jefferson Lab experiment), and the results.
263. Nuclear/Riken Theory Committee
"On Pressure Isotropization in Heavy-Ion Collisions"
Presented by Bin Wu, The Ohio State University
Friday, June 24, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Soeren Schlichting''
In this talk, I would like to start with a brief introduction to non-equilibrium quantum field theory in the Schwinger-Keldysh formalism. This formalism provides a systematic way to study isotropization and other time-dependent non-equilibrium (and equilibrium) phenomena in heavy-ion collisions. I shall first discuss the foundation of classical field approximations (CSA), which is an important tool to study the evolution at very early stages. It is, however, found to be non-renormalizable. This helps us understand better the applicability of such an approximation. it is now well-known that isotropization can not be established before the breakdown of the CSA. We then use another approximation, the quasi-particle approximation (the Boltzmann equation), to study the isotropization in a scalar field theory. Our result shows explicitly the importance of quantum effects. Motivated by these observations, we have been studying whether the isotropization can be reached before the dense system of gluons, produced in the collisions of two big nuclei, becomes too dilute to be studied perturbatively in the Schwinger-Keldysh formalism. Some preliminary results shall be reported.
264. RIKEN Lunch Seminar
"Leading log resummation in high-energy parton production in QCD matter"
Presented by Bin Wu, The Ohio State University
Thursday, June 23, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Hiroshi Oki'
265. Physics Colloquium
"Sterile Neutrinos as the Origin of Dark and Baryonic Matter"
Presented by Mikhail Shaposhnikov, EPFL
Tuesday, June 21, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: 'Robert Pisarski'
I will discuss how three sterile neutrinos alone can simultaneously explain neutrino oscillations, the observed dark matter, and the baryon asymmetry of the Universe without new physics above the Fermi scale. The experimental prospects to search for these particles will be outlined.
266. Nuclear Physics Seminar
"The Quest for the Origin of the Proton's Sea"
Presented by Paul Reimer, Argonne National Lab
Tuesday, June 21, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Oleg Eyser'
The proton is a composite particle in which the binding force is responsible for the majority of its mass. To understand this structure, the distributions and origins of the quark-antiquark pairs produced by the strong force must be measured. The SeaQuest collaboration is using the Drell-Yan process to elucidate antiquark distributions in the proton and to study the modification of these distributions when the proton is held within a nucleus. Preliminary results based on a fraction of the anticipated final data set will be presented.
267. Nuclear Physics Seminar
"Lattice constraints on the thermal dilepton and photon rate"
Presented by Olaf Kaczmarek, Bielefeld University
Friday, June 17, 2016, 2 pm
Small Seminar Room, Bldg. 510
We estimate the dilepton and photon production rate from an SU(3) plasma at temperatures of about 1.1 Tc to 1.5 Tc. Lattice results for the vector current correlator at zero and non-zero momenta are extrapolated to the continuum limit and analyzed with the help of phenomenological and perturbative input for the corresponding spectral functions. We compare our results with NLO weak-coupling results, hydrodynamics, and a holographic model. At vanishing invariant mass we extract the photon rate which for k>3T is found to be close to the NLO weak-coupling prediction. For k
268. RIKEN Lunch Seminar
"Static and dynamic screening effect on the resonant $\alpha-\alpha$ scattering in a QED plasma"
Presented by Xiaojun Yao, Duke University
Thursday, June 16, 2016, 12:30 pm
Building 510, Room 2-84
Hosted by: 'Hiroshi Oki'
269. Environmental & Climate Sciences Department Seminar
"High-Resolution Photography of Clouds from the Surface: Retrieval of Cloud Optical Depth down to Centimeter Scales"
Presented by Stephen Schwartz, Environmental and Climate Sciences Department
Thursday, June 16, 2016, 11 am
Conference Room, Bldg 815E
Initial results are presented of a analysis of high resolution photographs of clouds at the ARM SGP site in July, 2015. A commercially available camera having 35-mm equivalent focal length up to 1200 mm (nominal resolution as fine as 6 µrad, which corresponds to 12 mm for cloud height 2 km) is used to obtain a measure of zenith radiance of a 40 m x 40 m domain as a two-dimensional image consisting of 3456 x 3456 pixels (12 million pixels). Downwelling zenith radiance varies substantially within single images and between successive images obtained at 4-s intervals. Variation in zenith radiance found on scales down to about 10 cm is attributed to variation in cloud optical depth (COD). Attention here is directed primarily to optically thin clouds, COD less than roughly 3. A radiation transfer model used to relate downwelling zenith radiance to COD and to relate the counts in the camera image to zenith radiance, permits determination of COD and cloud albedo on a pixel-by-pixel basis. COD for thin clouds determined in this way exhibits considerable variation, for example, an order of magnitude within the 40 m domain examined here and 50% over a distance of 1 m. An alternative to the widely used areal or temporal cloud fraction, denoted radiative cloud fraction, also evaluated on a pixel-by-pixel basis, is introduced. This highly data-intensive approach, which examines cloud structure on scales 3 to 5 orders of magnitude finer than satellite products, opens new avenues for examination of cloud structure and evolution.
""Design Considerations for the 1.3GHz SRF Cavity for ARIEL at TRIUMF""
Presented by Dr. Philipp Kolb, BNL
Wednesday, June 15, 2016, 4 pm
Bldg. 911B - Large Conf. Rm. Rm A202
"The Advanced Rare IsotopE Laboratory (ARIEL) at TRIUMF will triple the available rare isotope beam (RIB) time for experiments. The major part of ARIEL is the 50 MeV, high intensity cw eLINAC based on 1.3GHz SRF cavities. An eventual addition to the eLINAC is a recirculating beam line to allow FEL-ERL operation in addition to the RIB production beam. To avoid multipass beam break-up (BBU), the design of the SRF cavity had to be modified to reduce the shunt impedance of dipole higher order modes (HOM). Work on the cavity design and HOM load measurements will be shown as well as results of the vertical and horizontal cavity tests."
271. Condensed-Matter Physics & Materials Science Seminar
"Quantiative Determination of the the Fluctuations Leading to Superconductivity in Cuprates"
Presented by Chandra Varma, University of California, Riverside
Tuesday, June 14, 2016, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: 'Peter D. Johnson'
I will report on Laser based ARPES of unprecedented accuracy and stability (taken by the group of Xingjiang Zhou, IOP, Beijing), together with a method of analysis suggested by me (and carried out with the group of Han-Yong Choi, Asia Pacific Center for Theoretical Physics, Korea), to quantitatively extract the e↵ective frequency and momentum dependent interactions of fermions in both the full symmetry (normal) and the d-wave (pairing) symmetry in a family of cuprates. The results are remarkably simple. The principal interactions are of the form: I(k, k',w)~g0 [(1−cos(20k)cos(20'k)]F(w) They are separable functions of momentum and frequency, the first part is the repulsive part and the second part is the attractive d-wave part. F(w) is nearly constant with an upper-energy cutoff of about 0.4eV. The dimensionless coupling constant g0 ~ 0.15. These results were predicted in a theory of superconductivity and of the strange metal phase by quantum-critical fluctuation of loop-currents. They also rule out several alternatives proposed. I will also comment on the normal state and superconductivity in the Fe-based compounds.
272. Nuclear Physics Seminar
"Measurement of high-mass muon pairs from ultraperipheral lead-lead collisions with the ATLAS detector at the LHC"
Presented by Peter Steinberg, BNL
Tuesday, June 14, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Oleg Eyser'
Exclusive dimuon pairs with invariant mass Mμμ>10 GeV have been measured in ultra-peripheral lead-lead collisions at √sNN=5.02 TeV, using an integrated luminosity of 515 μb−1 taken with the ATLAS detector at the LHC in 2015. These very low-multiplicity interactions were recorded using an experimental trigger requiring a muon, low total transverse energy recorded in the calorimeter system, gaps at forward angles, and a reconstructed track. Events are selected to have no-other final state particles than a pair of opposite-sign dimuons. The cross section for dimuon pairs in Pb+Pb collisions is presented as a function of pair mass (Mμμ) and pair rapidity (Yμμ) and is well-described by calculations of Pb+Pb→Pb(*)+Pb(*)+μ+μ− using STARLIGHT 1.1 calculations. These data will improve the understanding of the strong electromagnetic fields surrounding the nucleus, which enable future UPC measurements utilizing these high energy probes.
273. Nuclear Seminar
"Generalizations of relativistic hydrodynamics"
Presented by Piotr Surowka, Harvard
Friday, June 3, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Yi Yin'
Recent developments have shown that relativistic Landau and Lifshitz hydrodynamics does not possess the most general structure. It has to generalized to account for new phenomena. I will show how to do that in two directions. One will include parity-odd transport contributions connected to anomalies, the other will capture a dissipative fluid coupled to non-Abelian degrees of freedom such as color currents or spin currents. I will mention possible applications to quark-gluon plasma and condensed matter systems.
274. Nuclear Seminar
"Global Hyperon Polarization in Semicentral Heavy Ion Collisions Measured by STAR"
Presented by Mike Lisa, Ohio State University
Tuesday, May 31, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Oleg Eyser'
Non-central collisions between ultra-relativistic heavy ions involve thousands of h-bar of angular momentum. Some of this angular momentum may be transferred to the quark-gluon plasma through shear forces that generate a vortical substructure in the hydrodynamic flow field. Understanding this fundamental femtoscopic substructure may be crucial, as we move beyond boost-invariant scenarios and rely more on sophisticated three-dimensional viscous models of the plasma. The vortical nature of the system is expected to polarize the spins of hadrons that eventually emerge. Lambda and Anti-Lambda hyperons, which reveal their polarization through their decay topology, should be polarized similarly in the direction of the system's angular momentum. These same collisions are also characterized by dynamic magnetic fields with magnitude as large as 10^{14} Tesla. Magnetic effects have been the focus of intense study in recent years due to their relevance to the Chiral Magnetic Effect (CME) and other novel phenomena. A splitting between Lambda and Anti-Lambda polarization may signal a magnetic coupling and provide a quantitative estimate of the field strength at freeze out. Physically, this strength depends on the conductivity of the QGP. The STAR Collaboration has made the first observation of global hyperon polarization along the direction of the angular momentum in non-central Au+Au collisions at Beam Energy Scan energies. Our preliminary results indicate that the QGP created at RHIC is the highest-vorticity fluid ever created in the laboratory. A magnetic splitting is hinted at, but the improved statistics and resolution achievable with future runs are required to make a definitive measurement of the magnetic field.
275. Particle Physics Seminar
"Searching for Sterile Neutrinos with MINOS"
Presented by Ashley Timmons, University of Manchester
Thursday, May 26, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: '''Xin Qian'''
276. RIKEN Lunch Seminar
"Lefschetz-thimble path integral for studying the sign problem and Silver Blaze phenomenon"
Presented by Yuya Tanizaki, RBRC
Thursday, May 26, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Hiroshi Ohki'
Recently, Picard-Lefschetz theory gets much attention in the context of the sign problem, because it enables us to study the system with the complex classical action nonperturbatively by employing the semiclassical analysis. In this seminar, after its brief introduction, I will apply it to the one-site Hubbard model. This model has a severe sign problem, which looks quite similar to that of the finite-density QCD at low temperatures. By solving this model using the Lefschetz-thimble path integral, we are trying to understand the structure of the sign problem of finite-density QCD. Especially, I give a qualitative picture (or speculation) about the early-onset problem of the baryon number density, called the baryon Silver Blaze problem. The complex Langevin method will also be discussed if time allows.
277. High Performance Computing and Programming Event
"OpenACC and GPU Hands-on workshop"
Presented by Presented by NVIDIA instructor Bob Crovella
Wednesday, May 25, 2016, 8:30 am
Stony Brook University
NVIDIA and the Institute for Advanced Computational Science (IACS) at Stony Brook University are pleased to be organizing a 2-day High Performance Computing and Programming event. Presented by NVIDIA instructor Bob Crovella, the workshop will introduce programming techniques using OpenACC and will include topics such as optimization and profiling methods for GPU programming.
278. Nuclear Physics Seminar
"Exploring the Neutron Spin Structure"
Presented by Matt Posik, Temple University
Tuesday, May 24, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: 'Oleg Eyser'
Jefferson Lab experiment E06-014, performed in Hall A, made measurements of the double-spin asymmetries and absolute cross sections in both the DIS and resonance regions by scattering longitudinally polarized electrons at beam energies of 4.74 and 5.89 GeV from a longitudinally and transversely polarized 3He target. Through these measurements various aspects of the neutron spin structure were investigated. The g2 nucleon spin-dependent structure function contains information beyond the simple parton model description of the nucleon. It provides insight into quark-gluon correlations and a path to access the confining local color force a struck quark experiences just as it is hit by the virtual photon due to the remnant di-quark. The quantity d2, a measure of this local color force, has its information encoded in an x2 weighted integral of a linear combination of spin structure functions g1 and g2 and thus is dominated by the valence-quark region at large momentum fraction x. To date, theoretical calculations and experimental measurements of the neutron d2 differ by about two standard deviations. Therefore E06-014 made a precision measurement of this quantity. The polarized quark distributions were also investigated through measurements of the virtual photon-nucleon asymmetry A1^n, the structure function ratio g1/F1, and quark ratio (delta d+delta d_bar)/(d+d_bar). The E06-014 results for the spin structure functions (g1,g2) on 3He, dn2, An1, (delta d+delta d_bar)/(d+d_bar), and our extractions of the neutron color electric and magnetic forces will be presented.
279. High Performance Computing and Programming
"OpenACC and GPU Hands-on workshop"
Presented by Presented by NVIDIA instructor Bob Crovella
Tuesday, May 24, 2016, 8:30 am
Stony Brook University
NVIDIA and the Institute for Advanced Computational Science (IACS) at Stony Brook University are pleased to be organizing a 2-day High Performance Computing and Programming event. Presented by NVIDIA instructor Bob Crovella, the workshop will introduce programming techniques using OpenACC and will include topics such as optimization and profiling methods for GPU programming.
280. Nuclear Theory/RIKEN Seminar
"The jet quenching parameter q-hat, and its relation to the TMDPDF"
Presented by Abhijit Majumdar, Wayne State University
Friday, May 20, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: '''Soeren Schlichting'''
Based on prior work by the JET collaboration, the importance of the factorization and scale evolution of the jet quenching parameter q-hat will be outlined. This will turn out to be important for both phenomenological extractions of q-hat as well as for first principle determinations on the lattice. I will argue that for jets at RHIC and LHC, q-hat does not lie within the range of Bjoerken-x where small x effects would be considered to be dominant. Given this situation, q-hat will be found to be an integral over an operator product separated in both light-cone and transverse distance, but somewhat different from a traditional'' TMDPDF. This new distribution will be studied at Next-to-Leading Order and the fate of non-standard divergences discussed.
281. Particle Physics Seminar
"Searches for New Physics in boosted diboson topologies at ATLAS"
Presented by Carmacho Toro, University of Chicago
Thursday, May 19, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Michael Begel'
The large increase in collision energy that the LHC reached in Run 2 provides an unprecedented opportunity to search for new physics beyond the Standard Model (SM). Various extensions of the SM predict the existence of heavy resonances at the TeV scale, which couple predominantly to the Higgs and electroweak gauge bosons. At high resonance masses the hadronic decay products of these energetic bosons tend to be highly collimated and the usual identification techniques fail to disentangle the decay products of our bosons. In this seminar I will describe the jet-substructure techniques explored by ATLAS analyses and present the results of the ATLAS searches using Run-2 data.
282. RIKEN Lunch Seminar
"Kosterlitz-Thouless transition and chiral rotation in external electromagnetic field"
Presented by Gaoqing Cao, Fudan University
Thursday, May 19, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Daniel Pitonyak''
In 2+1 dimensional system, the most important phase transition should be of the Kosterlitz-Thouless (KT) type. We determined the KT transition temperature T_KT as well as the mass melting temperature T^* as a function of the magnetic field. It is found that the pseudogap domain T_KT < T < T^* is enlarged with increasing strength of the magnetic field. The influence of a chiral imbalanceμ_5 was also studied. We found that even a constant axial chemical potential μ_5 can lead to inverse magnetic catalysis of the KT transition temperature in 2+1 dimensions. This is actually the de Haas—van Alphen oscillation. Furthermore, we studied the QCD vacuum structure under the influence of an electromagnetic field with a nonzero second Lorentz invariant I_2=E·B. We showed that the presence of I_2 can induce neutral pion (π_0) condensation in the QCD vacuum through the electromagnetic triangle anomaly. Within the frameworks of chiral perturbation theory at leading small-momenta expansion as well as the Nambu—Jona-Lasinio model at leading 1/Nc expansion, a universal dependence of the π_0 condensate on I_2 was found. The stability of the π_0-condensed vacuum is also discussed.
283. HET/RIKEN Seminar
"Higgs Pair Production in Extensions of the Standard Model"
Presented by Ramona Groeber, Roma Tre
Wednesday, May 18, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Pier Paolo Giardino'
Higgs pair production is not only interesting as a probe of the trilinear Higgs self-coupling, but beyond the Standard Model physics can influence the Higgs pair production cross section in many different ways, for example by new couplings, new loop particles or new resonances. In this talk, I will address the question whether we could see for the first time deviations from the Standard Model in Higgs pair production assuming that no deviations were seen before. Furthermore, for certain models I will show how higher order corrections influence the cross section.
284. Condensed-Matter Physics & Materials Science Seminar
"Equilibrium States and Dynamics of Spin Assemblies in Magnetic Thin Films, Heterostructures and Nanostructured Entities"
Presented by Ramesh B. Budhani, Indian Institute of Technology Kanpur
Tuesday, May 17, 2016, 11 am
Building 480, Conference Room
Hosted by: 'Lijun Wu'
The orientation of spin assemblies in ferromagnetic thin films and nanostructures can take a variety of shapes depending on the relative strength of factors contributing to their magnetic free energy. These factors are derived from the direct quantum mechanical exchange between the electronic spins or those mediated by impurities, and those associated with the size, shape, crystallographic structure, strain, dipolar interactions and external fields. Here we present three cases where the orientational dynamics has been studied as functions of temperature, magnetic field strength and the elapsed time after acquiring a particular configuration. These studies are based on magnetic force microscopy and bulk magnetometry measurements on strain epitaxial films of La0.67Ca0.33MnO3, and lithographically patterned submicron size ring assemblies of permalloy and Co/Pd multilayers, which also form artificial spin ices. Towards the end of this lecture we will discuss interface driven magnetic and electronic phenomena in magnetic thin films.
285. Condensed-Matter Physics & Materials Science Seminar
"Dirac Materials"
Presented by Alexander Balatsky, Los Alamos National Laboratory
Monday, May 16, 2016, 11 am
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: 'Peter D. Johnson'
Discoveries of superfluid phases in 3He, high Tc superconductors, graphene and topological insulators have brought into focus materials where quasiparticles are described by same Dirac equation that governs behavior of relativistic particles. I will discuss how this class of materials, called Dirac materials, exhibits unusual universal features seen in numerous realizations: Klein tunneling, chiral symmetries and impurity resonances. Goal of this talk is to explore these similarities and discuss the unique role of symmetries that protect Dirac spectrum and possible routes to generate gaps due to many body instabilities. We will also discuss ongoing investigation of the symmetries of Dirac materials, quantum imaging, and means to control their properties. At the end we will propose to use modern tools to design artificial Dirac Materials. One example would be the design Bosonic Dirac materials that host bosonic Dirac excitations, something that would not be possible in particle physics.
286. Nuclear Theory/RIKEN Seminar
"Evolution of the jet opening angle distribution in holographic plasma"
Friday, May 13, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Soeren Schlichting''
Energetic jets are particularly interesting probes of QGP created in heavy ion collisions. Recently a lot of progress was made in attempting to describe the jet evolution in holography. In this talk I'll present an application of a simple dual model to study the jet substructure starting with energy and angle distributions from pQCD. In particular I will show that there are two competing effects: (1) each individual jet widens as it propagates through plasma; (2) the final jet opening angle distribution becomes narrower since wider jets lose more energy and less likely to survive. So, the mean opening angle for jets with a given energy can easily shift toward smaller angles, even while every jet in the ensemble broadens.
287. Particle Physics Seminar
"Muon antineutrino oscillations at T2K"
Presented by Jordan Myslik, University of Victoria
Thursday, May 12, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
The T2K ("Tokai to Kamioka") experiment is a long-baseline neutrino oscillation experiment in Japan. A beam of muon neutrinos or muon antineutrinos is produced at the Japan Proton Accelerator Research Complex (J-PARC) in Tokai. The unoscillated neutrino flux is measured by the near detector complex 280 m from the proton target, and the oscillated neutrino flux is measured by the far detector, Super-Kamiokande, 295 km away. Using a beam of muon neutrinos, T2K has performed precise measurements of muon neutrino disappearance, and discovered muon neutrino to electron neutrino oscillation by measuring electron neutrino appearance. Since the summer of 2014, T2K has been taking data using a beam of muon antineutrinos, and has released the results of both a muon antineutrino disappearance analysis and an electron antineutrino appearance analysis, both using antineutrino beam data up to the summer of 2015. This talk will discuss these analyses, going into detail about the role played by the near detector, and looking at future directions.
288. RIKEN Lunch Seminar
"The Functional Renormalization Group Method and Delayed Magnetic Catalysis"
Presented by Stefan Rechenberger, University of Darmstadt
Thursday, May 12, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Daniel Pitonyak''
This talk will start with a very general introduction to the Functional Renormalization Group method, a powerful non-perturbative tool which can be applied to various problems. The second part of the talk will demonstrate this by discussing the influence of an external magnetic field on the chiral phase transition in the theory of strong interaction. The Functional Renormalization Group analysis shows that, driven by gluon dynamics, the chiral critical temperature decreases for small values of the magnetic field. For large values of the external field, however, the phase transition temperature increases.
289. HET/RIKEN Seminar
"Axions and Topology"
Presented by Simon Mages, Forschungszentrum Juelich
Wednesday, May 11, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Tomomi Ishikawa''
This talk will be centered around the calculation of the high temperature topological susceptibility in QCD. It will provide some background on our motivation from cosmology and particle physics, which is the dependence of axion physics on non-perturbative QCD. I will show our recent results on the quenched high temperature topological susceptibility and discuss difficulties with this conventional approach, which render dynamical studies unfeasible. I will also present our new approach based on formulating QCD on a non-orientable manifold, which is a promising candidate to solve issues related to topological freezing and the divergence of autocorrelations when approaching the continuum limit.
290. Nuclear Theory/RIKEN seminar
"Fluid dynamics for the anisotropically expanding quark-gluon plasma"
Presented by Dennis Bazow, The Ohio State University
Friday, May 6, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Soeren Schlichting''
Local momentum anisotropies become large in the early stages of the quark-gluon plasma created in relativistic heavy-ion collisions, due to the extreme difference in the longitudinal and transverse expansion rates. In such situations, fluid dynamics derived from an expansion around an isotropic local equilibrium state is bound to break down. Instead, we subsume the slowest nonhydrodynamic degree of freedom (associated with the deviation from momentum isotropy) at leading order defining a local anisoptropic quasi-equilibrium state, thereby treating the longitudinal/transverse pressure anisotropy nonperturbatively. Perturbative transport equations are then derived to deal with the remaining residual momentum anisotropies creating a complete transient effective theory called viscous anisotropic hydrodynamics. This approach has been shown to dramatically outperform viscous hydrodynamics in several simplified situations for which exact solutions exits but which share with realistic expansion scenarios the problem of large dissipative currents. We will discuss the present status of applying viscous anisotropic hydrodynamics to the phenomenological description of the quark-gluon plasma in realistic expansion scenarios.
291. Particle Physics Seminar
"Probing the Nature of Neutrinos with Double Beta Decay"
Presented by Liang Yang, University of Illinois at Urbana-Champaign
Thursday, May 5, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
Understanding fundamental properties of neutrinos is of compelling interest to the nuclear and particle physics community. The discovery of neutrino oscillations is one of our first hints of physics beyond the Standard Model. Searching for neutrinoless double decay can provide key insights into the neutrino mass generation mechanism and put stringent constraints on the absolute neutrino mass scale. Such a rare decay, if exists, would signify the Majorana nature of neutrinos and the non-conservation of lepton number. In the past decade, large ultra-low background liquid xenon detectors have emerged as a promising technology that can push the neutrinoless double beta decay search to unprecedented sensitivity. In this talk I will describe recent results and prospects of current generation experiment EXO-200, as well as the R&D program for future tonne scale detector nEXO.
292. RIKEN Lunch Seminar
"Vorticity in heavy-ion collisions and cold atoms"
Presented by Xu-Guang Huang, Fudan University
Thursday, May 5, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Daniel Pitonyak''
Vorticity describes the local rotation of the fluid. I will talk about our recent study of the event-by-event generation of flow vorticity in heavy-ion collisions. Several special properties of the vorticity in heavy-ion collisions will be discussed, e.g., the impact parameter dependence, the collision energy dependence, the spatial distribution, the event-by-event fluctuation of the magnitude and azimuthal direction. Vorticity can drive vector and axial current in chiral quark-gluon plasma via the chiral vortical effect. I will discuss the collective gapless mode, the chiral vortical wave, emerging from CVE and its experimental implications in heavy-ion collisions. Finally, I will consider the rotating trapped cold atomic gases and show that when there is a Weyl spin-orbit coupling such cold atomic gases provide a desktop simulator of the chiral magnetic effect and chiral separation effect.
293. HET/RIKEN Seminar
"Calculating TMDs and DPDs on the lattice"
Presented by Andreas Schaefer, University of Regensburg
Wednesday, May 4, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Tomomi Ishikawa'
294. Physics Colloquium
"eRHIC Machine Design"
Presented by Thomas Roser, BNL
Tuesday, May 3, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: 'Robert Pisarski'
With the addition of a 20 GeV polarized electron accelerator to the existing Brookhaven Relativistic Heavy Ion Collider (RHIC), the world?s only high energy heavy ion and polarized proton collider, a future eRHIC facility will be able to produce polarized electron-nucleon collisions at center-of-mass energies of up to 145 GeV and cover the whole science case as outlined in the Electron-Ion Collider White Paper and endorsed by the 2015 Nuclear Physics Long Range Plan with high luminosity. The presentation will describe the eRHIC design concepts and recent efforts to reduce the technical risks of the project.
295. High Tc Superconductor Seminar
"Cooper-like paring and energy gap induced by ion electronic polarizability"
Presented by Yizhak Yacoby, Racah Institute of Physics, Hebrew University, Israel
Monday, May 2, 2016, 1:30 pm
Bldg. 734, ISB Conference Room 201 (upstairs)
Hosted by: ''Ron Pindak and Ivan Bozovic''
We propose a model of Cooper-like pairing induced by the large ion polarizabilities of O2- in Bismutates and Cuprates and As3- and Se2- in the iron pnictides*. We show that the electrical potential field induced by a charge carrier contains in its vicinity pockets of negative potential causing charge carriers to attract each other. Using this model we calculate the approximate pairing and gap energies showing they are compatible with the gap energies measured in high-Tc superconductors. Furthermore we show that the isotope effect, coherence length, and the gap energy dependence on doping are consistent with those observed in high-Tc systems. * Work done in collaboration with Yakov Girshberg
296. Nuclear Theory/RIKEN Seminar
"Going with the flow: sign problem, Lefschetz thimbles and beyond"
Presented by Gokce Basar, University of Maryland
Friday, April 29, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: '''Soeren Schlichting'''
Monte Carlo method, a robust way of studying field theories and many body systems, suffers from the sign problem when the action is complex. This includes an important set of problems such as most field theories, including QCD, and strong correlated electronic systems at finite density, as well as computation of real time quantities like transport coefficients. I will show that lifting the path integration to a complex manifold provides a way to ameliorate the sign problem, and introduce a new algorithm for carrying on such a computation. I will give some quantum mechanical examples with severe sign problems, including finite density of fermions and real time observables where Monte Carlo simulations can be profitably performed by this method. Finally I will discuss the 3+1d Bose gas with nonzero chemical potential.
297. Particle Physics Seminar
"Higgs' invisible branching fraction at the LHC"
Presented by Tae Min Hong, University of Pennsylvania
Thursday, April 28, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Michael Begel'
Does the Higgs have a large invisible branching fraction? Two approaches are presented. The first is an indirect constraint of the invisible branching fraction using precision Higgs couplings measurements. The second is a direct search of invisible decays. In particular, I will discuss in detail two of ATLAS's results: the H -> WW in VBF, which is one of the strongest inputs for the couplings and the evidence for VBF Higgs production, and the H -> invisible in VBF, which gives the strongest direct limit. Comparisons with CMS's results are made.
298. RIKEN Lunch Seminar
"Solving QCD2"
Presented by Alexei Tsvelik, BNL
Thursday, April 28, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: 'Daniel Pitonyak'
We study a (1+1)-dimensional version of the famous Nambu-Jona-Lasinio model of Quantum Chromodynamics (QCD2) both at zero and finite chemical potential. We use non- perturbative techniques (non-Abelian bosonization and Truncated Conformal Space Approach). At zero chemical potential we describe a formation of fermion three-quark (nucleons and ?-baryons) and boson (two-quark mesons, six-quark deuterons) bound states and also a formation of a topo- logically nontrivial phase. When the chemical potential exceeds the critical value, the model has a rich phase diagram which includes phases with density wave and superfluid quasi-long-range (QLR) order and also a phase of a baryon Tomonaga-Luttinger liquid (strange metal). The QLR order results as a condensation of scalar mesons (the density wave) or six-quark bound states (deuterons).
299. HET/RIKEN Seminar
"Heavy Higgs Resonance Dip"
Presented by Sunghoon Jung, SLAC
Wednesday, April 27, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Cen Zhang''
We discuss overlooked resonance shapes of heavy Higgs bosons that arise from the resonance-continuum interference with a complex phase. They include pure resonance dips and nothingness. We derive conditions under which they are produced and we modify narrow width approximation suitable for them. We then discuss how MSSM heavy Higgs searches at the LHC can be challenged and changed.
300. Physics Colloquium
"Neutrino Physics and Mass from Cosmology"
Presented by Marilena Loverde, Stony Brook University
Tuesday, April 26, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: 'Robert Pisarski'
Cosmic background neutrinos are nearly as abundant as cosmic microwave background photons, but their mass, which determines the strength of their gravitational clustering, is unknown. Neutrino oscillation data gives a strict lower limit on neutrino mass, while cosmological datasets provide the most stringent upper limit. Even if the neutrino masses are the minimum required by oscillation data, their gravitational effects on structure formation will nevertheless be detectable in — and in fact required to explain — data within the next decade. I will discuss the physical effects of the cosmic neutrino background on structure formation and present a new signature that may be used to measure neutrino mass with large galaxy surveys.
301. Center for Functional Nanomaterials Seminar
"Disordered water phases from ambient to ultrahigh pressure"
Presented by Roberto Car, Princeton University
Tuesday, April 26, 2016, 11 am
CFN, Bldg. 735, 2nd Fl. Seminar Room
Hosted by: 'Deyu Lu'
Center for Functional Nanomaterials Special Seminar Disordered water phases from ambient to ultrahigh pressure Roberto Car Princeton University Tuesday, April 26, 2016 11:00 a.m. CFN, Bldg. 735, 2nd floor Seminar Room The unusual properties of water, including the thermodynamic anomalies of the liquid, the existence of more than one amorphous ice form, and the abnormal mobilities of the water ions, derive from the tetrahedral network of hydrogen bonds that hold the molecules together. Under applied pressure the topology of the network changes but local tetrahedrality is preserved as the system explores a variety of different phases until at extreme pressure the molecules dissociate into ions and the hydrogen bonds collapse. Modern ab-initio simulations provide a unifying picture of these processes. In this talk, I will review recent progress in these studies stressing connections between theory, simulation, and experiment. Bio Roberto Car of Princeton University is Ralph W. Dornte professor for chemistry with a simultaneous appointment at the Material Sciences Institute of the university. He is a professor in the Theory Department, of the Fritz Haber Institute of the Max Planck Society. His research focus is theory and numerical simulation (classical and quantum) of condensed and molecular systems. He studied physics and attained a doctorate in 1971 in nuclear technology at the Politecnico di Milano. After being professor for physics at SISSA in Trieste (1984-1991), and at University of Geneva (1991-1999) he joined Princeton University in 1999. In 2007, a birthday symposium was held at ICTP. He received the Aneesur Rahman prize in computational physics. The Aneesur Rahman Prize is the highest honor given by the American Physical Society for work in computational physics.
Presented by Malek Haj Tahar, BNL
Friday, April 22, 2016, 4 pm
Large Conference Room, Bldg. 911B, Rm. A202
"The problem of nuclear waste continues to raise lots of concerns of whether the nuclear power should continue when the issue of how to deal with its waste has not yet been resolved. After reviewing the history of the nuclear waste problem in the United States of America and other countries, the question of how to remediate this problem is tackled and several options discussed. The focus is on the Accelerator Driven System option, a hybrid technique combining a particle accelerator with a subcritical core. The scope includes technical considerations from the proton accelerator and up to the reactor core."
303. Nuclear Theory/RIKEN seminar
"A higher spin theory of neutral excitations of fractional quantum Hall fluids"
Presented by Dam T. Son, University of Chicago
Friday, April 22, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: '''Soeren Schlichting'''
304. Particle Physics Seminar
"New constraints on cosmic inflation from the Keck Array"
Presented by Chris Sheehy, University of Chicago
Thursday, April 21, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Anze Slosar'
The Keck Array, part of the BICEP/Keck program of small aperture cosmic microwave background (CMB) telescopes, is currently taking data at the South Pole in Antarctica. The goal of the BICEP/Keck program is to detect the B-mode pattern in the CMB's polarized anisotropy that would be a signature of cosmic inflation, or, barring a detection, to set upper limits that rule out some of the most favored theoretical scenarios. Previous results from BICEP2 and the Keck Array that detected B-modes at high significance consisted of data taken only at 150 GHz, and which could therefore not conclusively distinguish between a cosmological vs. galactic origin for the signal. A subsequent joint analysis with the Planck satellite collaboration that invoked their comparatively noisy but multifrequency maps revealed a large component of the signal to be from polarized thermal emission of galactic dust. In this talk, I will present the results from the first year of observations with Keck's new 95 GHz receivers. These results set the most stringent limits on cosmic inflation to date and mark the point at which CMB polarization now constrains inflation better than any other data set.
305. RIKEN Lunch Seminar
"Color fluctuation phenomena in high energy hadron & photon-A collisions"
Presented by Mark Strikman, Penn State University
Thursday, April 21, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: ''Daniel Pitonyak''
Compositeness of the bound states and the Lorentz slowing down of high energy interactions in QED and QCD lead to emergence of new coherent phenomena. We focus on the phenomena related to the fluctuations of the strength of interaction (color fluctuations phenomena). First we consider gross violations of the Glauber model for centrality dependence of production of the leading jets in pA scattering predicted earlier within QCD and recent evidence for this phenomenon from the studies of hard pA collisions at the LHC and dAu collisions at RHIC. Color fluctuations also explain a large suppression of the cross section of coherent vector meson photoproduction as compared to the Glauber model observed recently in the ultraperipheral collisions at LHC. We outline perspectives of future studies of the color fluctuation phenomenon in ultraperipheral heavy ion collisions at the LHC and electron - nucleus colliders.
306. Environmental & Climate Sciences Department Seminar
"Improved Tandem Measurement Techniques for Gas Phase Nanoparticle Analysis"
Presented by Vivek Rawat, University of Minnesota
Wednesday, April 20, 2016, 11 am
Conference Room, Bldg 815E
Hosted by: 'Jian Wang'
Non-spherical, chemically inhomogeneous nanoparticles are encountered in a number of natural and engineered environments, including combustion systems, reactors used in gas-phase materials synthesis, and in ambient air. To better characterize these complex nanoparticles, tandem measurement techniques are well suited, in which analytes are characterized by two orthogonal properties (e.g. size and mass). Tandem measurement techniques have been applied in a number of situations; however, there are still a considerable number of fundamental developments needed to advance these approaches. Specifically, new instrument combinations (with existing instruments) and appropriate data inversion routines need to be developed to determine combined two-dimensional mass-size distribution functions, pure mass distribution and for mobility-mass analysis for sub 2-nm clusters (ions). With this motivation, we first develop and apply a data inversion routine to determine the number based size-mass distribution function (two dimensional distribution) from tandem differential mobility analyzer-aerosol particle mass analyzer (DMA-APM) measurements, while correcting for multiple charging, instrument transfer functions and other system efficiencies. This two dimensional distribution can be used to calculate the number based size distribution or the mass based size distribution. We employ this technique to analyze various spherical and non-spherical nanoparticles and examine the validity of this approach by comparing the calculated size distribution functions and mass concentrations with direct measurements of these quantities. In a second study, we utilize a transversal modulation ion mobility spectrometer (TMIMS) coupled with a mass spectrometer (MS) to study vapor dopant induced mobility shifts of sub 2 nm ion clusters. Isopropanol vapor is introduced into the TMIMS, shifting the mobilities of ions to varying extents depending on ion surface chemistry, which provides an improved separa
307. Physics Colloquium
"The nature of the composite fermion in quantum Hall liquids"
Presented by Dam Thanh Son, University of Chicago
Tuesday, April 19, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: 'Robert Pisarski'
The quantum Hall liquids are some of the most nontrivial strongly interacting states of matter. Experiments have established the existence of the composite fermion as an effective degree of freedom of quantum Hall systems near half filling. A long-standing problem of existing theories of the composite fermion is the lack of particle-hole symmetry of the lowest Landau level. I will describe how the particle-hole symmetry took a central role in recent theoretical discussions of the fractional quantum Hall effect; in particular, how a recent synthesis, motivated by the physics of graphene and topological insulators, has lead to a new understanding of the low-energy quasiparticle of the half-filled Landau level. According to the new picture, the composite fermion is a Dirac particle, with a gauge but non-Chern-Simons interaction. Distinctive consequences of the new proposal are outlined.
308. Nuclear Theory/RIKEN seminar
"Vorticular fluid and Lambda Polarization in High-energy Heavy-ion Collisions"
Presented by Xin-Nian Wang, LBNL/CCNU
Friday, April 15, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Soeren Schlichting''
The strongly coupled quark-gluon plasma created in high-energy heavy-ion collisions has rich vortical structures that are caused by global total orbital angular momentum and transverse evolution of longitudinal flow. Fermions (quarks in sQGP phase and baryons in the hadronic phase) in such a vorticular fluid are naturally polarized due to spin-orbital. I will discuss both local and global quark polarization and how one can use the lambda polarization in the final state to study the vortical structure and constrain the transport properties of sQGP.
309. Particle Physics Seminar
"Nuclear reactor antineutrinos, hard to detect but with a traceable lineage."
Presented by Alejandro Sonzogni, BNL
Thursday, April 14, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
The antineutrino spectrum from nuclear reactors can be calculated using the so-called "summation method", which requires precise knowledge of the fission yield and decay properties of the about 1000 radionuclides produced in a reactor following the fission of the actinide fuel. Alternatively, the antineutrino spectra can also be calculated using the "conversion method", which relies on precisely measured electron spectra. We have recently updated both decay and fission data that enabled us to a) identify the nuclides that contributes the most at different energy regions, b) derive a systematic of the IBD cross section integrated spectra as function of Z and A, similar to that of beta-delayed neutrons, c) asses if an excess of antineutrinos observed at around 5.5 MeV can be discerned using nuclear data.
310. Center for Functional Nanomaterials Seminar
"Sub-50 fs Photophysics and Photochemistry of Transition Metal Complexes and Polyhalomethanes"
Presented by Sergey Mikhailovich Matveev, Bowling Green State University
Monday, April 11, 2016, 1:30 pm
CFN, Bldg. 735, 1st floor conf. rm. A
Hosted by: 'Mircea Cotlet'
Lowest energy electronic excited states (LEES) in transition metal complexes are the states most relevant for practical photophysical and photochemical processes. We investigated relaxation dynamic of two systems – copper chloride dianion with strong Jahn-Teller effect and hexabromoiridate dianion with spin-spin coupling, utilizing 2000 nm near-IR femtosecond (100 fs) pump-probe spectroscopy. In both systems, the Franc- Condon excited states of the transition metal complexes undergo internal conversion to the ground electronic states, but with significantly different lifetimes (55 fs and 360 ps, respectively), despite the fact that the metal-centered states are separated by the same energy gap (~5000 wavenumbers) from the respective ground state. This difference is explained by presence of a conical intersection between the first excited electronic and the ground states in the Cu(II) system due to strong Jahn-Teller linear distortion whereas the involved potential energy surfaces for the Ir(IV) complex are nested directly one above another. Another project under consideration is the ultrafast mechanisms of polyhalomethanes on the example of diiodomethane. This molecule has a tractable number of degrees of freedom, and, therefore, has served in literature as a model system for bond dissociation processes in both gas and condensed phases. In this work we implemented the state-of-the-art ultrafast (~35 fs) transient absorption experiment (supported by the most accurate multireference quantum chemical methods) to understand the UV photodissociation mechanism of methylene iodide molecules. We discovered previously unsuspected photochemical pathway in the UV photochemistry of methylene iodide, in which electronically excited molecules, rather than simply dissociate, undergo direct ~50-fs isomerization through a conical intersection into isomeric species. Host: Mircea Cotlet
311. HET/PARTICLE/RBRC Seminar
""Recent Highlights from CMS and from the 13 TeV run at the LHC""
Presented by Albert de Roeck, CERN/University of Antwerp
Friday, April 8, 2016, 2 pm
Large Seminar Room, Bldg. 510
Hosted by: '''Amarjit Soni'''
312. Particle Physics Seminar
"Dark Matter Search Results from PICO-2L"
Presented by Chanpreet Amole, Queen's University, SNOLAB
Thursday, April 7, 2016, 10 am
Small Seminar Room, Bldg. 510
Hosted by: 'Xin Qian'
New data are reported from a second run of the 2-liter PICO-2L C3F8 bubble chamber with a total exposure of 129 kg-days at a thermodynamic threshold energy of 3.3 keV. These data show that measures taken to control particulate con-tamination in the superheated fluid resulted in the absence of the anomalous back-ground events observed in the first run of this bubble chamber. One single nuclear-recoil event was observed in the data, consistent both with the predicted background rate from neutrons and with the observed rate of unambiguous multiple-bubble neutron scattering events. The chamber exhibits the same excellent electron-recoil and alpha decay rejection as was previously reported. These data provide the most stringent direct detection constraints on WIMP- proton spin-dependent scattering to date for WIMP masses < 50 GeV/c2.
313. 'Science on Tap'
"A Conversation With Paul Sorensen"
Presented by Paul Sorensen, Brookhaven Lab
Tuesday, April 5, 2016, 7 pm
Stony Brook Yacht Club
Hosted by: ''Alan Alda Center for Communicating Science''
Paul Sorensen recreates the birth of the universe, smashing the nuclei of gold atoms together with such extreme violence that they melt into a cosmic soup that hasn't existed since the universe was a microsecond old. In conversation with Stony Brook University's journalism professor, Steven Reiner, Sorensen will bring to vivid life the epic endeavor to create in Brookhaven National Laboratory's atom smasher minute specks of the hottest matter ever made on Earth, and tell us what these fleeting fireballs may reveal about the origin of everything, including ourselves.
314. Physics Colloquium
"Hunting for WIMPs in Panda Land"
Presented by Xiangdong Ji, University of Maryland
Tuesday, April 5, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: ''''Robert Pisarski''''
Weakly interacting massive particles (WIMPs), with properties similar to those of a heavy neutrino, have been a leading candidate for the 27% dark matter in the Universe. Direct detection experiments by detecting the nuclear recoils from elastic scattering of WIMPs with atomic nuclei have made huge strides in the last decade, improving the sensitivity by some five orders of magnitude. In this talk, I will describe the results from an adventure of searching for WIMPs with the PandaX, currently the most sensitive running liquid xenon dark matter detector, in the world's deep underground lab in the high mountains, western China.
315. Nuclear Theory/RIKEN seminar
"Studying Nucleons in Soliton Models"
Presented by Song Shu, Stonybrook University
Friday, April 1, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Soeren Schlichting''
Both chiral solitons and confined solitons are discussed at finite temperatures and densities in effective models. Based on the solitons the nucleon properties are studied in thermal medium. The nucleon mass in medium is carefully calculated. It is showed that the chiral solitons could even survive after the chiral phase transition, while confined solitons collapse after the system is deconfined.
316. Particle Physics Seminar
"Milicharge: A Proposal"
Presented by Ben Kaplan, New York University
Thursday, March 31, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Michael Begel''
I will present the status of the MilliQan experiment, a milli-charged particle detector we propose to install at LHC P5. The experiment would be commissioned during the next LHC shutdown in a service tunnel ~30m above the CMS interaction point, behind ~15m of rock. I will present the theoretical motivation for building the detector, its proposed experimental design, and the expected sensitivity to milli-charged particles.
317. RIKEN Lunch Seminar
"Sphalerons Far From Equilibrium and Associated Phenomena"
Presented by Mark Mace, Stony Brook University
Thursday, March 31, 2016, 12:30 pm
Building 510 Room 2-160
Hosted by: 'Daniel Pitonyak'
In this talk, I will present a first computation of sphalerons in the glasma; the highly occupied, weakly coupled gluon dominated pre-equilibrium matter created at early times after an ultra-relativistic heavy ion collisions. The sphaleron transition is a well known ingredient in the generation of anomalous vector current from a strong external magnetic field, the so-called Chiral Magnetic Effect. We perform classical-statistical real-time lattice simulations to study the dynamics of these topological transitions; simplifying our description by employing SU(2) gauge fields and neglecting the longitudinal expansion for this first study. I will show that the non-equilibrium sphaleron transition rate is time dependent and non-Markovian, in addition to being dominant in comparison to the thermal equilibrium sphaleron transition rate. In addition, we can measure the scaling and separation of physical scales in analogy to those from thermal equilibrium, in order to parameterize this rate and understand the approach to equilibrium. I will then demonstrate that it is the magnetic screening length, which we extract non-perturbatively, that controls this rate. Additionally, I will briefly mention studies of related anomalous transport effects that we plan on studying using this first principles classical-statistical real-time lattice technology.
318. Condensed-Matter Physics & Materials Science Seminar
"Topological Insulators and Dirac Semimetals - Recent Progress in New Materials"
Presented by Robert J. Cava, Princeton University
Thursday, March 31, 2016, 10 am
Large Seminar Room, Bldg. 510
Hosted by: ''Peter D. Johnson''
"New materials give new properties" describes the goal of our solid state chemistry research program. This goal would be much easier to attain if there was a reliable way to predict the stability of an unknown non-molecular solid, then predict what its properties would be, then make it as a real material and then finally test it, but unfortunately that is not the case; establishing such a process is the grand challenge in contemporary solid state chemistry, and so we have to operate differently. Our discussions with experimental and theoretical physicists teach us about current issues in the electronic and magnetic properties of matter, and our chemistry background teaches us how to think about crystal structures and bonding; our work is about trying to put these two cultures together to find new materials. In this talk I will describe some of our recent results in Topological Insulators and Dirac and Weyl Semimetals.
319. Physics Colloquium
"Quark-Gluon Plasma: An Old and New Phase of Quantum Matter"
Presented by Jinfeng Liao, Indiana University
Tuesday, March 29, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Robert Pisarski
The use of fire was instrumental for human civilization. Early conception of varied phases of matter as well as transitions among them, perhaps developed from e.g. burning wood and heating water. Those ancient pursuits continue into the modern quest for understanding the structure of matter under extreme conditions: what's the phase of matter when heated to unprecedented temperature? The answer to this question relies upon our understanding of the strong nuclear force, which is described by quantum chromodynamics (QCD). First principle calculations of QCD predict that the normal nuclear matter, when heated to be hot enough, will change into a new phase of matter called the quark-gluon plasma (QGP). In fact, the QGP was an old phase of matter that occupied the early universe shortly after the Big Bang. Today, such primordial droplets of QGP can be re-created repeatedly and measured precisely in relativistic heavy ion collisions (often called the Little Bangs). Remarkable discoveries have been made at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) that together reveal the QGP as a nearly perfect quantum liquid with superior opaqueness. We will discuss a number of novel properties of QGP. In particular we will highlight the recent progress on how certain unusual transport phenomena stemming from microscopic chiral anomaly, which is intrinsically quantum mechanical, could manifest themselves in the macroscopic QGP fluid. A very brief survey will be given on the theoretical developments, the experimental search in heavy ion collisions, as well as the recent exciting progress of such physics in Dirac and Weyl semimetals.
320. Particle Physics Seminar
"Exotic BSM Higgs Decays and proposed LHC Benchmarks"
Presented by Shufang Su
Thursday, March 24, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Bill Marciano'
321. Condensed-Matter Physics & Materials Science Seminar
"Phase transitions in strongly correlated systems from diagrammatic multi-scale methods"
Presented by Andrey Antipov, University of Michigan
Thursday, March 24, 2016, 1:30 pm
Bldg. 734, ISB Conf. Rm. 201 (upstairs)
Hosted by: ''Alexei Tsvelik''
The dynamical mean field theory (DMFT) has become the standard tool in describing strongly correlated electron materials. While it captures the quantum dynamics of local fields, it neglects spatial correlations. To describe e.g. anti-ferromagnetism, unconventional superconductivity or frustration a proper treatment of non-local correlations is necessary. Diagrammatic multi-scale approaches offer an elegant option to accomplish this: the difficult correlated part of the system is solved using a non-perturbative many-body method, whereas 'easier', 'weakly correlated' parts of the problem are tackled using a secondary perturbative scheme. Here we employ such a method, the dual fermion approach, to problems of charge and spin ordering in Falicov-Kimball and Hubbard models by constructing a systematic diagrammatic extension on top of DMFT. Near the critical point model we study the interplay between charge and spin excitations and long-range fluctuations. We show that such multi-scale approach is indeed capable of capturing the non mean-field nature of the critical point of the lattice model and correctly describes the transition to mean-field like behavior as the number of spatial dimensions increases. Our numerical method is available as a freely distributed open-source code.
322. Special RIKEN/HET Seminar
"Axion Phenomenology from Unquenched Lattice QCD"
Presented by Guido Martinelli, Rome University
Thursday, March 24, 2016, 11 am
Large Seminar Room, Bldg. 510
Hosted by: '''Hiroshi Oki'''
We investigate the topological properties of Nf = 2 + 1 QCD with physical quark masses, both at zero and finite temperature. At zero temperature both finite size and finite cut-off effects have been studied by comparing the continuum extrapolated results for the topological susceptibility χ with the predictions from chiral perturbation theory. At finite temperature, we explore a region going from Tc up to around 4Tc, where continuum extrapolated results for the topological susceptibility and for the fourth moment of the topological charge distribution are obtained. While the fourth moment converges to the dilute instanton gas prediction the topological susceptibility differs strongly both in the size and in the temperature dependence. This results in a shift of the axion dark matter window of almost one order of magnitude with respect to the instanton computation.
323. Physics Colloquium
"Flavor Physics for Non Experts : (A Theory) Overview"
Presented by Guido Martinelli, Rome University
Tuesday, March 22, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Robert Pisarski
The status of the Unitarity Triangle including the most recent results from LHC, will be presented. Different possibilities for detecting, in the quark sector, signals of physics beyond the Standard Model will be considered. The conclusion is that, even allowing for general New Physics loop contributions, the generalized Unitarity Triangle must be very close to the Standard Model one. Together with direct searches of new particles at LHC, this result strongly constraints models of New Physics.
324. Condensed-Matter Physics & Materials Science Seminar
"SU(N) symmetric tensor network simulations of strongly correlated quantum many-body systems"
Presented by Andreas Weichselbaum, Ludwig Maximilians University
Tuesday, March 22, 2016, 1:30 pm
Small Seminar Room, Bldg. 510
Hosted by: ''Alexei Tsvelik''
Tensor network simulations have emerged as a powerful algebraic framework for the simulation of strongly correlated quantum many-body systems. Their great appeal lies in the fact that they are exact in that they do no rely on small parameters. They significantly extend exact diagonalization to much larger system sizes in (effective) 1D or 2D all the way to the thermodynamic limit. I will give a brief introduction based on the hugely successful methods such as the numerical renormalization group (NRG) or the density matrix renormalization group (DMRG) with focus on multi-orbital systems, both symmetric and non-symmetric. A versatile numerical tool in that respect is my recently developed tensor library QSpace that can efficiently deal with generic symmetry settings including SU(N). After a brief motivation via the prototypical symmetric multi-orbital system of iron impurities in gold or silver, I will present recent results on a dynamical mean-field theory (DMFT) study concerning the coherent-incoherent crossover in iron-pnictides, followed by recent work on the spin-1 Heisenberg kagome lattice and preliminary results on SU(N) spin ladders.
325. Condensed-Matter Physics & Materials Science Seminar
"From Molecular Beam Epitaxy to high magnetic field Quantum Oscillations"
Presented by Yoshiharu Krockenberger, NTT Basic Research Laboratories
Monday, March 21, 2016, 1:30 pm
Bldg.480 Conf. Rm
Hosted by: 'Ivan Bozovic'
Cuprate superconductors present a major challenge in condensed matter physics not only due to their electron correlations but also due to their complex crystal structure. Complex crystal structures, i.e. various cations at various lattice positions, demand for the utmost caretaking when synthesizing them. In particular, Molecular Beam Epitaxy is the foremost versatile tool and technique that allows for the synthesis of such materials without the necessity to compromise on impurity phases. First, I introduce our custom designed Molecular Beam Epitaxy equipment which is empowered by e-guns, not effusion cells, and controlled by electron impact emission spectroscopy. After presenting several material systems I present high magnetic field quantum oscillation data on films synthesized by our Molecular Beam Epitaxy systems.
326. Nuclear Theory/RIKEN Seminar
"Duality, Dimensions and Reduction on the Lattice"
Presented by Joel Giedt, Rensselaer Polytechnic Institute
Friday, March 18, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Montonen and Olive found evidence that a duality could exist in Yang-Mills with adjoint scalars. In this scheme, the 't Hooft-Polyakov monopole forms a gauge triplet with the photon, leading to a theory equivalent to the Georgi-Glashow model but with magnetic charge replacing electric charge. The duality is believed to be realized in N=4 super-Yang-Mills. We are pursuing numerical, nonperturbative evidence for this S-duality using our lattice formulation. Two lines of approach are being taken, which I will discuss. First, we attempt to show that there is a value of the gauge coupling for which the W boson mass is equal to the monopole mass. Second, we are relating the 't Hooft loop to the Wilson loop at this self-dual coupling. On a somewhat unrelated topic, we also discuss the determination of anomalous dimensions on the lattice. In the dual gravitational picture these correspond to masses of fields in the bulk, so that some aspects of the gauge-gravity duality could be tested by such determinations. In particular in N=4 super-Yang-Mills there are predictions for the dimensions of non-protected operators at the self-dual point, based on the superconformal bootstrap.
327. HET/RIKEN Seminar
""Operator Bases and Effective Field Theories""
Presented by Brian Henning, Yale University
Wednesday, March 16, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: 'Cen Zhang'
328. Physics Colloquium
"Hot-dense Lattice QCD: Supercomputing Extreme Matter"
Presented by Swagato Mukherjee, BNL
Tuesday, March 15, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: 'Rob Pisarski'
I will discuss the role of supercomputing in revealing the phases and properties of the hot-dense quark-gluon matter created during relativistic heavy-ion collisions. I will present a brief overview of the recent achievements of ab-initio lattice Quantum Chromodynamiecs computations at non-zero temperatures and densities.
329. Particle Physics Seminar
"New SUSY Results from ATLAS"
Presented by Max Swiatlowski
Thursday, March 10, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Michael Begel
330. Condensed-Matter Physics & Materials Science Seminar
"Real-space Visualization of the Superconducting Proximity effect and Josephson tunneling on Nano-sized Pb thin film"
Presented by Howon Kim, Institute for Solid State Physics, University of Tokyo, Japan
Wednesday, March 9, 2016, 11 am
ISB Bldg. 734 Conf. Rm. 201 (upstairs)
Hosted by: Kazuhiro Fujita
The proximity and Josephson effects are well-known phenomenon and widely used terms in superconductivity. Due to the recent advances in fabrication techniques those phenomenon has been extensively studied to give a new insight to the superconductor-based device applications. Nevertheless, many of these works addressed macroscopic properties of the samples, and thus local information is still missing. In this talk, I will discuss how we can realize the proximity effect and Josephson effect using scanning tunneling microscope at a nanometer scale. In the first part of the talk, we address how the local surface structure can influence on the proximity effect at the interface between superconducting two-dimensional Pb islands and a single-atomic-layer metal by performing local tunneling spectroscopy. From the spectroscopic mapping taken around the Pb-based S/N interface, we observed the gap at the Fermi energy, reminiscent of the superconducting gap, propagating into the metal region (proximity effect) and its depth decaying with the distance from the interface. Additionally, we observed that the propagation of the gap is terminated by the steps of the substrate and enhancement of the gap-depth in the area between the interface and the step edge. The experimental results are compared with the results of quasi-classical theory based on the Usadel equation. [1] The second part of the talk addresses atomic-scale S-S junctions by using scanning tunneling microscopy and spectroscopy. In our local conductance measurements between superconducting Pb islands on Si(111) or Ge(111) and Pb layers on the end of PtIr tip apex, we observed evolution of not only the normal-state conductance [2] but also a zero-bias peak (ZBP) from tunnel to atomic contact, which corresponds to the Josephson current, with a decrease in the tip-substrate distance on the different atomic sites on the surface crystalline lattice of the substrate. With a help of multiple Andreev reflectio
331. Environmental & Climate Sciences Department Seminar
"Plant respiration: lessons from high latitudes for ecosystem carbon balance modelling"
Presented by Paul P. Gauthier, Princeton University
Wednesday, March 9, 2016, 11 am
John Dunn Seminar Room, Bldg. 463
Hosted by: Alistair Rogers
Climate-mediated changes in ecosystem C balance are accepted as an important component of the biosphere response to climate change. Plant respiration and photosynthesis are major drivers of this balance but our lack of understanding of the controls and constrains surrounding their interaction stalls our capacity to predict future ecosystem changes. Using a new O2 isotopes method for measuring leaf functional traits, I will present a new approach to estimate the rate of leaf respiration in the light and its biochemical origin in temperate and arctic plants. The role of plant respiration as a key player for plant adaptation will also be discussed in the context of plant respiration modelling.
332. RIKEN Lunch Seminar
"Investigation of anomalous dynamics and the Chiral Magnetic Effect far from equilibrium"
Presented by Niklas Mueller, University of Heidelberg
Thursday, March 3, 2016, 12:30 pm
Building 510, Room 2-160
Hosted by: Daniel Pitonyak
We investigate the impact of the Adler-Bell-Jackiw axial anomaly on the real-time dynamics of gauge theories in the strong field regime. By studying and comparing Abelian gauge theories, such as QED, with non-Abelian systems, we try to clarify the role of topological properties and initial conditions relevant far from equilibrium. We show that the Abelian version of the Chiral Magnetic Effect, which has been predicted in the context of ultra-relativistic heavy ion collisions, can result in non-trivial experimental signatures, which could possibly be observed in future high-intensity laser experiments. Further I will report on recent investigations of chiral production mechanisms in strong non-Abelian gauge fields and I will discuss the influence of topological objects such as sphalerons, far from equilibrium. Moreover I will show first results of the studies we have undertaken since my arrival here at BNL and discuss how the combination of these studies might be used to shed more light on the role played by anomalies in the early stages of a heavy ion collision.
333. HET/RIKEN Seminar
"Accurate event simulation for colliders"
Presented by Stefan Prestel, SLAC
Wednesday, March 2, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Cen Zhang
334. Physics Colloquium
"Detection of Gravitational Waves and the First Observation of a Binary Black Hole Merger"
Presented by Imre Bartos, Columbia University
Tuesday, March 1, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Peter Petreczky
On September 14th 2015 the gravitational wave signature of a binary black hole merger was detected by the LIGO observatories. This marks the beginning of a completely new era of modern physics, the dawn of gravitational-wave astrophysics. We will discuss the discovery, its impact and its consequences.
335. Nuclear Physics Seminar
"Beam Energy Dependence of the Third Harmonic of Azimuthal Correlations in Au+Au Collisions at RHIC"
Presented by Paul Sorensen, BNL
Tuesday, March 1, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Oleg Eyser
I will present results from a harmonic decomposition of two-particle azimuthal correlations measured with the STAR detector in Au+Au collisions for energies ranging from 7.7 GeV to 200 GeV. v3 is studied as a function of the pseudorapidity di erence between particle pairs. Non-zero v3 is directly related to the previously observed large- narrow- ridge correlations and has been shown in models to be sensitive to the existence of a low viscosity Quark Gluon Plasma (QGP) phase. For sufficiently central collisions, v3 persist down to an energy of 7.7 GeV suggesting that QGP may be created even in these low energy collisions. In peripheral collisions at these low energies however, v3 is consistent with zero. When scaled by pseudorapidity density of charged particle multiplicity per participating nucleon pair, v3^2 for central collisions shows a minimum near 20 GeV.
336. Particle Physics Seminar
"Observation of Gravitational Waves from a Binary Black Hole Merger by LIGO"
Presented by Sergey Klimenko, University of Florida
Monday, February 29, 2016, 3 pm
Large Seminar Room, Bldg. 510
Hosted by: Erin Sheldon
On September 14, 2015 at 09:50:45 UTC the Laser Interferometer Gravitational-wave Observatory (LIGO) Hanford, WA, and Livingston, LA, observatories detected a strong coincident signal. The signal matches the waveform predicted by general relativity for the inspiral merger of a pair of black holes and the ringdown of the resulting single black hole. A century after the fundamental predictions of Einstein and Schwarzschild, the gravitational waves are captured. I will present the details of this observation and discuss the results.
337. Nuclear Theory/RIKEN Seminar
"Real time method of thermal field theory"
Presented by Samir Mallik, Saha Institute of Nuclear Physics
Friday, February 26, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
I review the basic ideas of real time formulation of thermal field theory. Then I like to consider the following topics in this formulation: 1) thermal propagator for a scalar field 2) spectral representation of two-point functions for arbitrary fields 3) perturbation expansion 4) one-loop self -energy 5) dilepton production
338. Particle Physics Seminar
"Project 8: tritium decays, neutrino masses, and single-electron spectroscopy"
Presented by Prof. Ben Monreal, UC Santa Barbara
Friday, February 26, 2016, 10 am
Small Seminar Room, Bldg. 510
Hosted by: Xin Qian
Beta decay kinematics are, in principle, sensitive to the absolute values of the neutrino masses. Many decades of work with tritium decay have shown m_nu to be in the range 0—2.0 eV; require improvement in spectrometer resolution, statistics, and systematics. The KATRIN experiment will push the limits of classical techniques to reach 0.2 eV sensitivity. The Project 8 is developing what we hope is the next step in beta electron spectroscopy; we can now perform precise electron energy measurements, in-situ in a low-pressure gaseous source, by cyclotron radiation energy spectroscopy (CRES). I will show recent results from the Project 8 prototype, including the first CRES measurements in krypton, and our path to first molecular tritum measurements and to a future large atomic tritium experiment.
339. Particle Physics Seminar
"Giant detectors in solution-mined salt caverns"
Presented by Prof. Ben Monreal, UC Santa Barbara
Thursday, February 25, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Xin Qian
Many of particle physics' most interesting observables (neutrinos, dark matter, proton decay) require detectors installed underground. In many cases, the constraints associated with mines—-limited roof spans, limited sites, safety, and excavation costs—- are beginning to limit the scope of our experiments. The energy and chemical industries have 100 years of experience with a different type of underground space: solution-mined salt caverns. These are obtained by drilling into large salt formations and dissolving the salt with water. The caverns obtained can be enormous, deep, stable and above all inexpensive—-but of course they have their own access and pressure constraints. In this talk, I will argue that a wide range of desirable detector technologies, including giant gas TPCs, might be deployed with these caverns. In particular, I will talk about an (untested) TPC gas mixture I devised with these caverns in mind, but which may prove useful in conventional labs too.
340. RIKEN Lunch Seminar
"Lambda_c - N interaction from lattice QCD"
Presented by Takaya Miyamoto, Yukawa Institute for Theoretical Physics, Kyoto University
Thursday, February 25, 2016, 12:30 pm
Building 510 Room 2-160
Hosted by: Hiroshi Oki
Recently, a new approach to investigate hadron interactions in lattice QCD has been proposed[1] and developed extensively by the HAL QCD Collaboration[2]. This method can be easily applied to heavy baryon systems even though it is difficult to obtain experimental data of heavy baryons. We have investigated the interaction between Lambda_c and nucleon (N) from lattice QCD using the HAL QCD method. This is the first step to understand charmed-baryon interaction in lattice QCD. In this talk, we present the current status of our research project onLambda_c-N interactions as well as future prospects. This talk is based on PoS (LATTICE 2015) 090.
341. Brookhaven Lecture
"512th Brookhaven Lecture: Quarks, Gluons & Lattice QCD: Cooking the 'Perfect' Soup With Supercomputers"
Presented by Swagato Mukherjee, Physics Department at Brookhaven Lab
Wednesday, February 24, 2016, 4 pm
Berkner Hall Auditorium
342. Nuclear Theory/RIKEN Seminar
"Lattice QCD investigations of quark transverse momentum in hadrons"
Presented by Michael Engelhardt, New Mexico State University
Friday, February 19, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
An ongoing program of evaluating transverse momentum dependent parton distributions (TMDs) within lattice QCD is reviewed, summarizing recent progress with respect to several challenges faced by such calculations. These lattice calculations are based on a definition of TMDs through hadronic matrix elements of quark bilocal operators containing staple-shaped gauge connections. A parametrization of the matrix elements in terms of invariant amplitudes serves to cast them in the Lorentz frame preferred for a lattice calculation. Results presented include data on the naively T-odd Sivers and Boer-Mulders effects, as well as the transversity and a worm-gear distribution. Correlating quark transverse momentum with impact parameter, one can extract quark orbital angular momentum directly,including both the Ji as well as the Jaffe-Manohar definitions.
343. Nuclear/Riken Theory Seminar
"The Transverse Structure of the Nucleon"
Presented by Marc Schlegel, University of Tuebingen
Friday, February 19, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Perturbative QCD based on the Parton Model of the nucleon is a very successful theoretical approach to describe high-energy processes at particle accelerators and colliders. In particular, parton distribution functions are key ingredients of this approach and give information on the partonic substructure of the nucleon. As such they deliver a one-dimensional picture of how the parton momenta are distributed in the nucleon. In this talk extensions of the parton model are presented which provide access to more detailed information on the dynamics of partons in the nucleon. In particular observables involving transversely polarized nucleons are discussed. They can be described in terms of dynamical quark-gluon correlations which in turn can be studied at an Electron-Ion Collider. Another extension of the parton model takes into account the intrinsic transverse motion of the partons. In this approach - called Transverse Momentum Dependent (TMD) factorization - one can study three-dimensional distributions of the parton momenta. In addition, implications of the transverse motion of gluons in the nucleon will be discussed for LHC physics.
344. Particle Physics Seminar
"Weighing the Giants: Anchoring Cluster Cosmology"
Presented by Adam Mantz, SLAC National Accelerator Laboratory
Thursday, February 18, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Erin Sheldon
The gas mass fractions and the distribution in mass and redshift of the galaxy cluster population provide powerful probes of cosmology, constraining the cosmic matter density, the amplitude of the matter power spectrum, properties of dark energy, and the mass of neutrinos, among other parameters. Historically, these tests have been limited by the absolute accuracy of cluster mass determinations. Here, mass measurements from weak lensing have an advantage over estimates based on observations of the intracluster medium (ICM), because the former are nearly unbiased and can be straightforwardly tested against simulations. I will describe recent cosmological constraints obtained from an analysis of X-ray selected cluster samples, incorporating extensive gravitational lensing data from the Weighing the Giants project — the first cluster cosmology study to consistently integrate a lensing mass calibration, including a rigorous quantification of all systematic uncertainties. The results highlight the power and potential of galaxy clusters, which constrain both the expansion of the Universe and the growth of cosmic structure, and their complementarity with other probes such as type Ia supernovae, large-scale galaxy surveys, and the cosmic microwave background.
345. Physics Colloquium
"Physics opportunities at future circular colliders"
Presented by LianTao Wang, University of Chicago
Tuesday, February 16, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Robert Pisarski
Following the discovery of the Higgs boson, there has been a lot discussion about the next step in high energy physics. Among different options, a couple of newly proposed next generation circular colliders, including FCC at CERN and CEPC/SPPC in China, have attracted a lot of attention. Through preliminary studies in the past couple of years, an exciting picture of their physics capabilities has emerged. In this talk, I will give an overview on this topic, focusing on some of the most important questions in high energy physics they can help addressing
346. Nuclear Physics Seminar
"Precision Jet Physics to Probe Strong Dynamics"
Presented by Dr. Daekyoung Kang, Los Alamos National Laboratory
Tuesday, February 16, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Oleg Eyser
Jets produced in the high energy collision of quarks and gluons at colliders are bunches of collimated particles traveling along the same direction. Jet productions are extensively studied in various colliders in search for new physics beyond the standard model and as a probe of new state of matter like QGP. In this talk, I will discuss jet study at a high precision as a new tool to probe strong dynamics in electron-proton collider. As an example, I will show the new tool can be used to determine the strong coupling constant and to improve our understanding of nuclear structure such as a parton distribution function of proton. With new level of precision not previously available for jets, the jet physics will provide one of milestones at the early stage of future Electron-Ion collider.
347. Nuclear Theory/RIKEN Seminar
"Understanding the structure of hadrons through spin observables in hard-scattering processes"
Presented by Daniel Pitonyak, BNL
Friday, February 12, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Almost all of the visible matter in the universe is built from hadrons, which are composed of quarks and gluons. One of the main challenges in nuclear physics is to understand this complex internal structure. In this talk, I will discuss how hard-scattering processes that involve the spin of hadrons give us insight into aspects of their inner-workings that otherwise would be inaccessible. I will focus on phenomena that arise when hadrons carry spin transverse to their direction of motion, which allow us to examine them in 3D and analyze correlations between their quarks and gluons. I will also consider a new attempt to resolve the so-called "spin crisis" of how the proton gets its spin by looking at how much spin can be carried by small-x quarks and gluons.
348. High Energy Theory/Particle Physics Seminar
"Illuminating the Dark Side of Particle Physics"
Presented by Eder Izaguirre, Perimeter Institute
Thursday, February 11, 2016, 3 pm
Large Seminar Room, Bldg. 510
Hosted by: Sally Dawson
349. Condensed-Matter Physics & Materials Science Seminar
"Berezinskii-Kosterlitz-Thouless-like transition in a highly underdoped La2-xSrxCuO4"
Presented by Dragana Popovic, NHMFL Tallahassee
Thursday, February 11, 2016, 1:30 pm
Bldg. 734, ISB Conf. Rm. 201 (upstairs)
Hosted by: Cedomir Petrovic
In two-dimensional superconductors, the transition to the metallic state takes place via thermal unbinding of vortex-antivortex pairs, as described by the Berezinskii-Kosterlitz-Thouless (BKT) theory. The occurrence of the BKT transition in bulk underdoped samples of cuprate superconductors, which are highly anisotropic, layered materials, has been controversial. Therefore, the nature of the superconducting transition in highly underdoped thick films of La2-xSrxCuO4 has been investigated using the in-plane transport measurements. Both the temperature dependence of the paraconductivity above the transition and the nonlinear current-voltage (I-V) characteristics across it exhibit the main signatures of the BKT transition. Moreover, the quantitative comparison of the superfluid stiffness, extracted from the I-V data, with the renormalization-group results for the BKT theory, reveals a large value of the vortex-core energy, strongly suggesting that the relevant length scale controlling the BKT-like transition in this layered material involves a few coupled layers. Finally, measurements of the fluctuations of the resistance with time (i.e. noise) provide evidence for the critical slowing down of the dynamics and the onset of correlated behavior. The details of the observed dynamical critical behavior of the BKT transition and the role of disorder will be discussed.
350. High Energy Theory
"Heavy Mesons in Jets"
Presented by Adam Leibovich, University of Pittsburgh
Wednesday, February 10, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Sally Dawson
351. Center for Functional Nanomaterials Seminar
"In situ studies of nucleation and growth of nanoparticles under realistic conditions"
Presented by Elena Schevchenko, Argonne National Laboratory
Monday, February 8, 2016, 11 am
Conference Room A, Bldg. 735
Hosted by: Oleg Gang
The progress in colloidal synthesis allowed reaching a high degree of controls in synthesis of nanoparticles. As a result, nanoparticles come in many different shapes, sizes and compositions. Combining multiple components within individual nanoparticles or doping of nanoparticles are simple ways to control chemical and physical properties at nanoscale to obtain efficient catalysts and advanced energy conversion and storage systems. However the successful synthetic protocols are based on empirical rules based on numerous trials and errors and often the mechanism of nucleation and growth of nanoparticles remains unclear. I will present in situ study on the nucleation and growth kinetics and the temporal changes in the crystal structure of the metal dumbbell NPs (e.g. CoPt3/Au, Pt/Au and PtFe/Au). Using synchrotron small- and wide-angle X-ray scattering (SAXS/WAXS) techniques we were able to catch the transient stages of structural and volumetric changes of NPs. We found that in the early stage of the reaction intermediate core/shell heterostructure is formed prior to dumbbells. The transition of the core/shell into the dumbbell occurs via strain relaxation of the pseudomorphic Au shell resulting in the nucleation of a strain-free Au domain. I will discuss the formation and doping process of iron and iron oxide NPs in real time by in situ synchrotron X-ray absorption spectroscopy. In our study we revealed that the mass flow of the metal triggered by oxidation is responsible for the internalization of the dopant (molybdenum) adsorbed at the surface of the host iron NPs. The new oxidation induced doping mechanism allows control over the doping levels by varying the amount of dopant precursor. Our in situ studies also showed that the dopant precursor substantially changes the reaction kinetics of formation of iron and iron oxide NPs.
352. High Energy Theory
"The Vector Portal: A Window to a Dark Sector"
Presented by Eder Izaguirre, Perimeter
Friday, February 5, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Sally Dawson
353. RIKEN Lunch Seminar
"Kinetic regime of hydrodynamic fluctuations"
Presented by Yukinao Akamatsu, Stony Brook University
Thursday, February 4, 2016, 12:30 pm
Building 510 Room 2-160
Hosted by: Hiroshi Ohki
Hydrodynamics is an effective theory of systems close to equilibrium. It has been applied to description of fireballs created in the heavy-ion collisions. With growing interests in fluctuation of observables, theoretical identification of its origin is crucial. One of such origins is thermal fluctuation required by the fluctuation-dissipation theorem. In this talk, I will present a new insight into the thermal fluctuation of hydrodynamics by separating the hard and soft scales in a given background. As an illustration, we adopt the Bjorken expansion as a background. The kinetic description of hard modes allows us simple interpretation of renormalization, long-time tails, and fractional powers of derivative expansion.
354. Physics Colloquium
"The New Big Science: the Changing Research Ecology at US Materials Science Facilities"
Presented by Robert Crease, Stony Brook University and, Catherine Westfall, Michigan State University
Tuesday, February 2, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Robert Pisarski
"We talk about a phase shift that has taken place over the past few decades at US national labs, in which large-scale materials science accelerators rather than high-energy physics accelerators became marquee projects at most major basic research laboratories in the post-Cold War era, accompanied by important changes in the character and culture of the research ecosystem at these laboratories. We consider some features, periodization, funding, and challenges of this phase shift, known as the "New Big Science."
355. Office of Educational Programs Event
"2016 High School Science Bowl"
Saturday, January 30, 2016, 8 am
Berkner Hall Auditorium
356. Nuclear Theory/RIKEN Seminar
"New aspects of QCD dynamics at high density: Jet evolution in the QGP and wave turbulence""
Presented by Yacine Mehtar-Tani, INT Seattle
Friday, January 29, 2016, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
An essential feature of the parton shower that form a jet evolving in vacuum is color coherence that suppresses large angle soft gluon radiation and thus, ensuing the collimation of the jet. In the presence of dense QCD matter jet constituents suffer a rapid color randomization and thus an alteration of color coherence: as a result a medium-induced gluon cascade, that can be described by a classical Makovian process, develop at large angles with respect to the jet axis [3]. A remarkable phenomenon emerges from such a cascade: the energy spectrum (of jet constituents) exhibits a scaling behavior, akin to wave turbulence, characterized by a constant flow of energy from the forward energetic patrons towards low momentum gluons down to the temperature of the plasma where energy is dissipated [4]. This picture is in agreement with a recent CMS analysis of missing energy in asymmetric dijet events where the energy balance is recovered at large angles and very soft particles [5]. In the second part of the talk I will discuss radiative corrections to jet observables that were shown to exhibit large double logarithmic enhancements. Owing to a large separation of time scales we have shown that these large corrections can be reabsorbed in a renormalization of the jet-quenching parameter q^, preserving the probabilistic picture of the parton cascade [6]. This result leads us to question the standard viewpoints of the coupling of jets to the medium: the naive perturbative approach based on a leading order calculation and the AdS/CFT correspondence for strongly coupled plasmas. I will briefly invoke in the final part of my talk the various questions that remain to be addressed. Indeed, despite the recent progress much remains to be understood about jet fragmentation in a dense medium in order to construct a systematic and predictive approach to jet-quenching from first principles.
357. Physics Colloquium
"Whole-brain neuronal connectivity mapping in the Mouse"
Presented by Partha Mitra, Cold Spring Harbor Laboratory
Tuesday, January 26, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Robert Pisarski
358. Nuclear Physics Seminar
"A Nuclear Physicist's Journey In Business: Lessons From the Front Office"
Presented by Daniel Magestro, Ph.D., International Institute for Analytics
Monday, January 25, 2016, 11 am
Large Seminar Room, Bldg. 510
Hosted by: Oleg Eyser
Companies in every industry are continually increasing their usage of large data sets and advanced statistical methods to understand customers and markets, improve operations, and forecast future business needs. The corresponding business demand for skilled analytical talent and "data scientists" has created a large talent gap for many companies that is predicted to surpass 100,000 nationally. Much of the talent gap arises from the hybrid skill set needed by data scientists that combines problem solving, technical, and communication skills. I will argue that the uniquely broad skill set of research scientists, and particularly experimental physicists in large collaborations, can bridge the growing talent gap for truly innovative companies.
359. Particle Physics Seminar
"Cross correlations with CMB secondaries: constraining cosmological parameters and cluster astrophysics"
Presented by Nick Battaglia, Princeton University
Thursday, January 21, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Anze Slosar
High resolution CMB experiments, such as ACT, SPT, and the Planck satellite are making precision measurements of the secondary anisotropies caused by the thermal Sunyaev Zel'dovich (tSZ) effect from galaxy clusters. However, our ability to obtain cosmological information from this tSZ signal is limited by our theoretical understanding of the baryons in clusters and groups. I will discuss how cross-correlation methods are providing new windows into the messy "Gastrophysics" of the intracluster medium and the potential for these methods to constrain various cosmological parameters.
360. Brookhaven Lecture
"511th Brookhaven Lecture: 'Following Fission Fragments: Nuclear Data for New Neutrino Physics'"
Libby McCutchan, Nuclear Science & Technology Department at Brookhaven Lab
Wednesday, January 20, 2016, 4 pm
Berkner Hall Auditorium
Hosted by: Thomas Watson
361. Physics Colloquium
"A bottom-up approach to modeling the sensory cortex"
Presented by Luca Mazzucato, Stony Brook University
Tuesday, January 19, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Robert Pisarski
In response to sensory stimulation, neurons can generate sequences of complex activation patterns. Yet, neurons in the sensory cortex are active even in the absence of overt sensory stimulation, producing a large amount of 'ongoing,' i.e. spontaneously generated, neural activity that is often indistinguishable from noise. Research in the last two decades suggests that ongoing neural activity may shed light on the architecture and dynamics of neural circuits. Here, I present a new framework encompassing both ongoing and stimulus-evoked neural activity, combining hidden Markov model analysis of neural recordings with biologically realistic models of cortical networks based on spiking neurons. This framework has been applied successfully to the sensory cortex and can be extended to other cortical systems. In the taste system, it has revealed new properties of single neurons and of neural populations, including a reduction of multi-stability and neural dimensionality in response to sensory stimuli, pointing to the existence of local neural clusters (yet to be experimentally confirmed). Using the analytical tools of effective mean field theory, one can explain these properties as emergent features of the network dynamics.
362. Particle Physics Seminar
"Search for Higgs Bosons produced in association with top quarks with the ATLAS detector"
Presented by Professor Vivek Jain, SUNY Albany
Thursday, January 14, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Ketevi Assamagan
Due to the large measured mass of the top quark, the Yukawa coupling of the top quark (yt) is much stronger than that of other quarks. The observation of the t¯tH production mode would allow for a direct measurement of this coupling, to which other Higgs production modes are only sensitive via loop effects. Since yt is expected to be close to unity, it is also argued to be the quantity that might give insight into the scale of new physics. Using various Higgs decay modes, we report on the status of this search using data collected with the ATLAS detector at 7 and 8 TeV collision energies.
363. RIKEN Lunch Seminar
"Confinement and Chiral symmetry breaking from an Interacting Instanton-dyon ensemble for 2 colors and Nf flavors"
Presented by Rasmus Larsen, Stony Brook University
Thursday, January 14, 2016, 12:30 pm
Building 510 Room 2-160
Hosted by: Daniel Pitonyak
I will present numerical results based on an interacting ensemble of instanton-dyons, that explains the connection between chiral symmetry breaking and confinement. The instanton-dyons have the nice properties to behave as monopoles at low temperatures, and as instantons at high temperatures. We will see how the scaling behavior of the instanton-dyons creates a Polyakov loop dependent potential, which forces the Polyakov loop to the confining value as the density of dyons increases at lower temperatures. For 2 flavors we find that the dominating configuration in the ensemble exhibit a chiral symmetry transition at the same temperature as the confinement transition, within accuracy. The important factor in explaining confinement and chiral symmetry breaking is the density of the Instanton-dyons.
364. Physics Colloquium
"From neV to MeV: Short-Range Fermion"
Presented by Or Hen, Laboratory for Nuclear Science, MIT
Tuesday, January 12, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Robert Pisarski
The atomic nucleus is composed of two different kinds of fermions, protons and neutrons. If the protons and neutrons did not interact, the Pauli exclusion principle would force the majority fermions, usually neutrons, to higher average momentum. In this talk I will present results from high-energy proton and electron scattering experiments, which show that short-range interactions between the fermions form correlated, high-momentum, neutronproton pairs. Thus, in neutron-rich nuclei the probability of finding a highmomentum (k>kFermi) proton (a minority Fermion) is greater than that of a neutron (a majority Fermion). This has wide ranging implications for atomic, nuclear, atomic, and astro physics, including neutrino-nucleus interactions, the EMC effect, the NuTeV anomaly, the nuclear symmetry energy and more. This feature is universal for imbalanced interacting Fermi systems and can also be observed experimentally in two-spin states ultra-cold atomic gas systems.
365. Nuclear Physics Seminar
"Short-Range Correlations in Nuclei â€" Current Status and Future Perspectives"
Presented by Or Hen, Laboratory for Nuclear Science, MIT
Tuesday, January 12, 2016, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Oleg Eyser
Results from recent experiments show that short-range interactions between the fermions form correlated, high-momentum, neutron-proton pairs. These pairs account for 20% - 25% of the nucleons in medium and heavy nuclei and dominate the momentum distribution of nucleons above the Fermi momentum of the nucleus. The observed dominance of these Short-Range Correlated (SRC) pairs by neutron-proton pairs shows the dominance of the tensor part of the nucleon-nucleon interaction at short distances. Recent works have shown that the existence and nature of SRC pairs has wide ranging implications for atomic, nuclear and astro physics, including neutrino-nucleus scattering, the EMC effect, the NuTeV anomaly, the nuclear symmetry energy. In this talk I will present the use of hard exclusive reactions for the study of SRCs, and discuss several open questions for next-generation experiment to address. I will present an experimental program based on proton, electron, and neutrino beams that can run at Dubna, GSI, JLab, Fermilab and perhaps even at BNL. I will also discuss the possibility of studying SRC pairs and their partonic structure at an EIC, using the method of spectator tagging in Quasi-elastic and Deep-Inelastic kinematics.
366. Particle Physics Seminar
"Reactor Antineutrino Flux and Spectrum"
Presented by Mr. Chao Zhang, BNL
Thursday, January 7, 2016, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Xin Qian
Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Accurate knowledge of reactor antineutrino production was crucial for those reactor experiments to achieve their goals. With the newest measurements from Daya Bay, I will revisit our current understanding of reactor antineutrino flux and spectrum, and its implications to future experiments.
367. Condensed-Matter Physics & Materials Science Seminar
"Electron Transport through a Proximitized Nanowire"
Presented by Leonid Glazman, Yale University
Thursday, January 7, 2016, 1:30 pm
Bldg. 734, ISB Conf. Rm. 201 (upstairs)
Hosted by: Alexei Tsvelik
Motivated by recent experiments on InAs nanowires with epitaxial Al we investigate the two-terminal conductance of a short proximitized nanowire. We identify the leading electron transport processes at zero applied magnetic field as well as at finite fields, which suppress the induced superconducting gap and drive the system towards the topological transition. In the conventional superconducting phase, the conductance is controlled by the sequential Cooper pair tunneling if the induced gap exceeds the charging energy of the nanowire, and by the elastic single-electron processes if the gap becomes smaller than the charging energy. The latter mechanism yields smaller values of the linear conductance and strongly asymmetric Coulomb blockade peaks, which may explain some experimental findings. Finally, we develop a quantitative theory for the conductance evolution across the transition into the topologically-nontrivial phase.
368. Physics Colloquium
"Search for hidden sector and invisible particles in the decay of the Higgs boson"
Presented by Ketevi Assamagan, BNL
Tuesday, January 5, 2016, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Peter Petreczky
The discovery of a Higgs boson at the LHC opens new research areas for instance the search for beyond-the-Standard-Model physics in the decays of the discovered Higgs boson. In events with large missing energy associated with jets, we search for the vector boson fusion production of the Higgs boson with forward jets, and the Higgs boson decays to invisible particles that result in large missing energy in the detector. An interpretation is done for the search for dark matter as a weakly interacting massive particle (WIMP) in the Higgs boson decays. We further carry out a statistical combination with other searches of Higgs boson decays to invisible particles to improve sensitivity. The current ATLAS exclusion limit combining all these searches is the best limit so far at the LHC on the invisible decay of the Higgs boson and the Higgs portal dark matter. In data events with four leptons in the final state, consistent with the decay of the Higgs boson to four leptons, we search for light-beyond-the-Standard-Model gauge boson Zdark that decay to a pair of same flavor and opposite sign leptons (electrons or muons): H -> Z(Zdark) Zdark -> 4l. The light gauge boson Zdark is predicted in extensions to the Standard Model to explain the muon g-2 anomaly and provide a candidate for dark matter.
369. RIKEN Lunch Seminar
"Baryon interactions from Lattice QCD by Luscher's finite volume method and HAL QCD method"
Presented by Takumi Iritani, Stony Brook University
Thursday, December 17, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Hiroshi Oki
Both Luscher's finite volume method and HAL QCD method are used to analyze the hadron-hadron interaction in lattice QCD. However, some systematic discrepancies are reported between them.For example, Luscher's method shows the bound states of both deuteron and di-neutron at the heavy pion mass,while these channels are scattering states from HAL QCD method. In this talk, to understand the deviations between them, we investigate the baryon interaction from both methods with the same lattice setups.From a systematic comparison of two methods, we clarify the problems in the previous studies. We also discuss the improvement of the analyses.
370. Physics Colloquium
"Experimental study of chiral and matter-antimatter symmetries at RHIC"
Presented by Aihong Tang, BNL
Tuesday, December 15, 2015, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Peter Petreczky
Symmetries and the physics laws that they dictate are fundamental in describing the physical world. In this talk I discuss two fundamental symmetries that are well suited to be studied at RHIC, namely, the chiral symmetry and the matter-antimatter symmetry. Under the hot and dense condition at RHIC, quarks and gluons are set free from protons and neutrons, making it feasible for the chiral symmetry to be restored. A restored chiral symmetry is a necessary requirement for the Chiral Magnetic Wave (CMW), a novel QCD phenomena, to propagate. The CMW has experimental consequences — it leads to the separation of elliptic flow between charged pions, which will be discussed in this talk. On the other hand, the abundantly produced antimatter at RHIC offers a unique opportunity to study the matter-antimatter symmetry. In particular the nuclear force between two antinucleons has not been measured previously, although the corresponding force for nucleons or nuclei has been well studied for decades. In this talk I will discuss the measurement of the nuclear force between two antiprotons and compare to that between protons. As direct information on the interaction between two antiprotons, one of the simplest systems of antinucleons, this result provides an elemental ingredient for understanding the structure of more complex antinuclear and their properties.
371. Nuclear Physics Seminar
"New surprises from RHIC-Spin: forward neutron transverse single spin asymmetry from p+A collisions from PHENIX"
Presented by Alexander Bazilevsky, BNL
Tuesday, December 15, 2015, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Oleg Eyser
A surprisingly large transverse single spin asymmetry (A_N) in forward neutron production was discovered during the first polarized proton RHIC run in 2002. It was immediately utilized for monitoring proton beam polarization in experimental collision regions at RHIC. Later it was shown that one pion exchange model for forward neutron production was successful to describe both cross section and A_N. RHIC new data from polarized proton on nucleus collisions from RHIC 2015 run brought new surprise - a strong dependence of the asymmetry on nucleus size (or charge). Results also were found to strongly depend on particle production in other rapidity regions, indicating that there might be multiple neutron production mechanisms generating single spin asymmetry.
372. Condensed-Matter Physics & Materials Science Seminar
"Soft mode branches, quantum central peak, and strong isotropic negative thermal expansion above a perovskite quantum phase transition"
Presented by Jason Hancock, University of Connecticut
Monday, December 14, 2015, 1:30 pm
ISB Conf. Room 201 (upstairs), Bldg. 734
Hosted by: Mark Dean
The importance of perovskite-structured materials to modern science cannot be understated, as they harbor diverse behavior and landscape of novel competing and intertwined phases. The structural phases of perovskites are critical to defining the framework of electronic conduction and magnetic exchange pathways in this interesting and technologically relevant class of materials. Large, isotropic negative thermal expansion is known to exist in only a handful of materials, beginning with the discovery of ZrW2O8 in the 1990s. In 2010, perovskite fluoride ScF3 was discovered to have a similarly profound negative thermal expansion (NTE) effect, shrinking in response to heat over a 1000 K temperature window with a linear thermal expansion coefficient lower than -10-5/K. Another curious property of this material is the structural stability â€" ScF3 retains a simple cubic structure and four atom unit cell from cryogenic temperature to its high melting point of 1800 K. ScF3 material does not feature the interesting phase competition of electrons and spin enjoyed by many of its oxide and fluoride cousins and can be classified as an ionic insulator. However the superlative nature of the NTE effect has motivated us to dive deeply into the lattice dynamics using high energy resolution inelastic X-ray scattering on strain-free single crystals. Surprisingly, we find that an entire optical mode branch circumscribing the Brillouin zone boundary softens to nearly zero frequency as the temperature T approaches T=0. ScF3 at T=0 thus sits in extreme proximity to a quantum phase transition. We interpret this result in the context of better studied trifluorides and examine in detail the disorder phase diagram. In addition, concomitant with softening of the optic branch, a quasielastic "central peak" (CP) emerges and strengthens toward low temperature, further bolstering the identification of a T=0 phase transition. The CP phe
373. Nuclear Theory/RIKEN seminar
"Evolution of gluon TMDs: from small to moderate x"
Presented by Andrey Tarasov, Jefferson Lab
Friday, December 11, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Recently we obtained an evolution equation for gluon TMDs, which addresses a problem of unification of different kinematic limits. It describes evolution in the whole range of Bjorken x and transverse momentum k⊥. I plan to discuss this evolution equation and show how in different kinematic regimes it yields several well-known and some previously unknown results.
374. Particle Physics Seminar
"Kinematic weak lensing"
Presented by Eric Huff, Ohio State University
Thursday, December 10, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Erin Sheldon
Kinematic measurements hold some promise of dramatically enhancing the prospects of traditional weak lensing. In this talk I outline the method and describe how it eliminates or suppresses the effects of traditional weak lensing systematic errors arising from shear calibration, photometric redshifts, and intrinsic alignments. I also discuss what it would take to scale kinematic lensing up to a level competitive with other advanced dark energy probes.
375. Condensed-Matter Physics & Materials Science Seminar
"TBA"
Presented by TBA, Stony Brook
Thursday, December 10, 2015, 2:45 pm
2nd Fl seminar room, Bldg. 734
Hosted by: Alexei Tsvelikl
376. Condensed-Matter Physics & Materials Science Seminar
"Magnetotransport in Weyl and Dirac Metals"
Presented by Gustavo Monteiro, Stony Brook University
Thursday, December 10, 2015, 1:30 pm
ISB Building, Room 201
Hosted by: Alexei Tsvelik
Dirac (Weyl) metals are characterized by the linear dispersion of electron quasiparticles, with the Dirac (Weyl) point hidden inside a Fermi surface. In this talk, I will refer to the so-called chiral kinetic theory to describe within the same framework both the negative magnetoresistance caused by the chiral magnetic effect (CME) and quantum oscillations in the magnetoresistance (SdH effect) due to the existence of the Fermi surface in these materials. I will also argue about the role of Fermi arcs and their contribution for the SdH modes. At last, I will discuss the relevance of obtained results to recent measurements on Cd As .
377. RIKEN Lunch Seminar
"Phase structure of lattice QCD with Wilson and twisted-mass fermions including isospin breaking"
Presented by Derek Horkel, University of Washington
Thursday, December 10, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Hiroshi Oki
As the precision frontier of particle physics continues to develop, the field of lattice QCD has risen to the challenge. Modern lattice simulations, have increasingly included light non-degenerate up and down quark masses and electromagnetism. Previously answered questions about the vacuum structure of QCD on the lattice must be reexamined when these isospin breaking effects are included. If not careful, lattice practitioners may simulate in non-physical phases which cannot be extrapolated to the continuum limit. Using chiral perturbation theory, I will discuss where these non-physical phases can arise for Wilson and twisted mass fermions. I will also explain some of the complications which arise when tuning the up and down twisted quark masses to their critical values in the presence of electromagnetism.
378. HET/RIKEN Seminar
"Developments in Scattering Amplitudes"
Presented by Ulrich Schubert, MPI, Munich
Wednesday, December 9, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Sally Dawson
379. Physics Colloquium
"What Stubs and Sparkles Will Tell Us About Exploding Stars"
Presented by Kate Scholberg, Duke University
Tuesday, December 8, 2015, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Peter Petreczky
When a massive star collapses at the end of its life, nearly all of the gravitational binding energy of the resulting remnant is released in the form of neutrinos. I will discuss the nature of the core-collapse neutrino burst and what we can learn about particle physics and about astrophysics from the detection of these neutrinos. I will cover supernova neutrino detection techniques in general, current supernova neutrino detectors, and prospects for specific future experiments.
380. Nuclear Physics Seminar
"Measurement of the transverse single-spin asymmetry in p+p->W±/Z0 at RHIC"
Presented by Salvatore Fazio, BNL
Tuesday, December 8, 2015, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Oleg Eyser
We present the measurement of the transverse single-spin asymmetry of weak boson production in transversely polarized proton-proton collisions at s√=500 GeV by the STAR experiment at RHIC. The measured observable is sensitive to the Sivers function, one of the transverse momentum dependent parton distribution functions, which is predicted to have the opposite sign in proton-proton collisions from that observed in deep inelastic lepton-proton scattering. These data provide the first experimental investigation of the non-universality of the Sivers function, fundamental to our understanding of QCD. The measured observable is also sensitive to the currently unconstrained Sivers function for the sea-quarks and to the evolution of the transverse-momentum dependent distribution functions.
381. Nuclear Theory/RIKEN Seminar
"Semi-classics, complex saddles and real path integrals"
Presented by Tin Sulejmanpasic, North Carolina State University
Friday, December 4, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
I will discuss the use of semi-classics and instanton calculus and argue that, contrary to common wisdom, complex solutions of the equations of motion are a necessary ingredient of any semi-classical expansion. In particular, I will show that without the complex solutions semi-classical expansion of supersymmetric theories cannot be reconciled with supersymmetry. This has a natural interpretation in the Picard-Lefschetz theory.
382. HET/RIKEN Lunch Seminar
"TBA"
Presented by Mattia Bruno and Pier Paolo Giardino, BNL
Friday, December 4, 2015, 12 pm
Building 510 Room 2-160
Hosted by: Amarjit Soni
383. RIKEN Lunch Seminar
"Sterile neutrino dark matter produced after the QCD phase transition"
Presented by Louis Lello, University of Pittsburgh
Thursday, December 3, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Daniel Pitonyak
Sterile neutrinos are SU(2) singlets that mix with active neutrinos via a mass matrix, its diagonalization leads to mass eigenstates that couple via standard model vertices. We study the production of sterile neutrinos in the early universe from pion decays shortly after the QCD phase transition in the absence of a lepton asymmetry. We introduce the quantum kinetic equations that describe their production, freeze out and decay and discuss the various processes that lead to their production in a wide range of temperatures assessing their feasibility as dark matter candidates. We consider the production of heavy neutrinos in the mass range < 140MeV from pion decay shortly after the QCD crossover including finite temperature corrections to the pion form factors and mass. We consider the different decay channels that allow for the production of heavy neutrinos showing that their frozen distribution functions exhibit effects from "kinematic entanglement" and argue for their viability as mixed dark matter candidates. We discuss abundance, phase space density and stability constraints and argue that heavy neutrinos with lifetime >1/H0 freeze out of local thermal equilibrium.
384. Physics Colloquium
Presented by Eric Swanson, University of Pittsburgh
Tuesday, December 1, 2015, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Peter Petreczky
A series of novel and unusual hadrons have been discovered since 2003. This talk will present an overview of these states with the purpose of learning what they reveal about the nonperturbative structure of Quantum Chromodynamics.
385. Nuclear Theory/RIKEN Seminar
"Transversity Distribution and Collins Fragmentation Functions with QCD Evolution"
Presented by Alexei Prokudin, Jefferson Lab
Friday, November 20, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
We study the transverse momentum dependent (TMD) evolution of the Collins azimuthal asymmetries in e+eâˆ' annihilations and semi-inclusive hadron production in deep inelastic scattering (SIDIS) processes. All the relevant coefficients are calculated up to the next-to-leading logarithmic (NLL) order accuracy. By applying the TMD evolution at the approximate NLL order in the Collins-Soper-Sterman (CSS) formalism, we extract transversity distributions for u and d quarks and Collins fragmentation functions from current experimental data by a global analysis of the Collins asymmetries in back-to-back di-hadron productions in e+eâˆ' annihilations measured by BELLE and BABAR Collaborations and SIDIS data from HERMES, COMPASS, and JLab HALL A experiments. The impact of the evolution effects and the relevant theoretical uncertainties are discussed. We further discuss the TMD interpretation for our results, and illustrate the unpolarized quark distribution, transversity distribution, unpolarized quark fragmentation and Collins fragmentation functions depending on the transverse momentum and the hard momentum scale. We make detailed predictions for future experiments and discuss their impact.
386. HET/RIKEN Lunch Seminar
"Collider Phenomenology of the Right Handed Heavy Neutrinos"
Presented by Arindam Das, University of Alabama
Friday, November 20, 2015, 12 pm
Building 510 Room-2-160
Hosted by: Amarjit Soni
We study the collider signature of pseudo-Dirac heavy neutrinos in the inverse seesaw scenario, where the heavy neutrinos with mass at the electro-weak scale can have sizable mixings with the Standard Model neutrinos, while providing the tiny light neutrino masses by the inverse seesaw mechanism. Based on a simple, concrete model realizing the inverse seesaw scenario, we fix the model parameters so as to reproduce the neutrino oscillation data and to satisfy other experimental constraints, assuming two typical flavor structures of the model and the different types of hierarchical light neutrino mass spectra. For completeness, we also consider a general parametrization for the model parameters by introducing an arbitrary orthogonal matrix and the nonzero Dirac and Majorana phases. We perform a parameter scan to identify an allowed parameter region which satisfies all experimental constraints. With the fixed parameters, we analyze the heavy neutrino signal at the LHC through trilepton final states with large missing energy and at the ILC through a single lepton plus dijet with large missing energy.
"Thousand Shades of Grey: From High School Intern to Medical Imaging Physics Graduate"
Megan Russ, University of Buffalo Toshiba Stroke and Vascular Research Center
Thursday, November 19, 2015, 4:30 pm
Large Seminar Room, Bldg. 510
Refreshments served before the talk.
388. RIKEN Lunch Seminar
"Viscous Velocity Gradient Correction to Thermal Photon Emission Rate at Strong Coupling"
Presented by Kiminad Mamo, University of Illinois at Chicago
Thursday, November 19, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Daniel Pitonyak
We compute the correction to the thermal photon emission rate in first order of shear components of fluid velocity gradients in near-equilibrium hydrodynamic plasma at strong coupling regime using the real-time Schwinger-Keldysh formalism in AdS/CFT correspondence. We find that the gradient correction to the thermal photon emission rate at strong coupling is about 0.3 - 0.4 times of the equilibrium rate.
389. Physics Colloquium
"IceCube: the High-energy Universe and Multimessenger Astrophysics with Neutrinos"
Presented by Imre Bartos, Columbia University
Tuesday, November 17, 2015, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Peter Petreczky
Astrophysical processes that produce the observed energetic cosmic particles (up to 10^20 eV) and high-energy gamma radiation involve extreme non-thermal acceleration, strongly constraining the list of possible sources. Nevertheless, the origin of the most energetic cosmic rays, and the electromagnetic emission mechanism in extreme sources such as gamma-ray bursts, are currently unknown. Neutrinos may well be the silver bullet to unravel these processes. They can reveal the hadronic nature of the emission, and due to their weak interaction they lead right back to the source. The IceCube neutrino observatory at the South Pole has recently discovered a cosmic flux of TeV-PeV neutrinos, making the first step in lifting the curtain on cosmic particle accelerators. I will discuss recent multimessenger observational developments, and source candidates in the high-energy universe. I will describe plans and capabilities for the next-generation neutrino detector IceCube-Gen2.
390. Nuclear Physics Seminar
"PHENIX measurements of single electrons from semi-leptonic charm and bottom hadron decays in Au+Au collisions"
Presented by Dr. Darren McGlinchey, University of Colorado, Boulder
Tuesday, November 17, 2015, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Jin Huang
Measurements of the modification of heavy quarks in heavy ion collisions provide constraints on energy loss in the Quark Gluon Plasma. The dead cone effect predicts a mass ordering to the modification, with the heavier bottom quark being less modified than the charm quark due to suppression of forward radiation. Therefore, measuring the modification of charm and bottom quarks separately can provide additional constraints on energy loss calculations. Previous PHENIX measurements of heavy flavor electrons indicated a substantial suppression relative to binary scaled p+p collisions at high transverse momentum. However, the inability to separate the contributions from charm and bottom hadron decays prevented a full understanding of the modification. Using the precise tracking capabilities provided by the PHENIX barrel Silicon Vertex Detector (VTX), we are now able to separate the contributions from charm and bottom hadrons to the measured heavy flavor electrons as a function of transverse momentum in Au+Au collisions at sqrt(s_NN)=200 GeV. These results will be discussed and compared with theoretical models.
391. Nuclear Theory/RIKEN Seminar
"Linearly resummed hydrodynamics from gravity"
Presented by Yanyan Bu, Ben Gurion University of the Negev
Friday, November 13, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Using fluid/gravity correspondence, we study all-order resummed hydrodynamics in a weakly curved spacetime. The underlying microscopic theory is a finite temperature \mathcal{N}=4 super-Yang-Mills theory at strong coupling. To linear order in the amplitude of hydrodynamic variables and metric perturbations, the fluid's stress-energy tensor is computed with derivatives of both the fluid velocity and background metric resummed to all orders. In addition to two viscosity functions, we find four curvature induced structures coupled to the fluid via new transport coefficient functions, which were referred to as gravitational susceptibilities of the fluid (GSF). We analytically compute these coefficients in the hydrodynamic limit, and then numerically up to large values of momenta. We extensively discuss the meaning of all order hydrodynamics by expressing it in terms of the memory function formalism, which is also suitable for practical simulations. We also consider Gauss-Bonnet correction in the dual gravity, which is equivalent to some 1/N corrections in the dual CFT. To leading order in the Gauss-Bonnet coupling, we find that the memory function is still vanishing.
392. HET/RIKEN Lunch Seminar
"Flavor physics with Lambda_b baryons"
Presented by Stefan Meinel, RBRC/ARIZONA
Friday, November 13, 2015, 12 pm
Building 510 Room 2-95
Hosted by: Amarjit Soni
393. Joint RIKEN Lunch/HET Seminar
"Gluon-fusion Higgs production: the final frontier"
Presented by Elisabetta Furlan, ETH, Zurich
Thursday, November 12, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Tomomi Ishikawa
The gluon-fusion Higgs production cross section has been recently computed through the next-to-next-to-next to leading order (N^3LO) in QCD. This unprecedented level of accuracy is crucial to exploit fully the LHC data in the validation of the Standard Model and in the search for potential (small) deviations due to new physics. I will give an overview of the tools that we employed to achieve this result, from the framework of heavy-quark effective theories to the analytical and mathematical machinery that we developed. I will conclude with some results and future prospects.
394. Nuclear Theory/RIKEN Seminar
"Massless QED in three dimensions with even number of flavors"
Presented by Rajamani Narayanan, Florida International University
Friday, November 6, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Massless QED in three (two space and one Euclidean time) with even number of flavors does not break parity. There are analytical arguments for chiral symmetry to be spontaneously broken and some numerical evidence supporting these arguments. An interesting "open" question is the possibility of a critical number of flavors below which chiral symmetry is broken. Numerical results obtained using dynamical Wilson fermions will be presented with emphasis on the behavior of the low lying eigenvalues of the Wilson Dirac operator. Finite volume analysis will be used to obtain conclusions about the absence or presence of a chiral condensate.
395. Particle Physics Seminar
"LAr TPC data reconstruction"
Presented by Dorota Stefan, CERN/NCBJ Warsaw Poland
Thursday, November 5, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Elizabeth Worcester
In recent years, there is much interest in building massive liquid argon time projection (LAr TPC) detectors to measure among others CP violation in leptonic sector, search for nucleon decay and study a core-collapse supernova via neutrinos. Data collected by ICARUS and ArgoNuet proved that LAr TPC calorimetric and spatial resolutions are excellent. The detector technology with no doubts is much advanced, resulting with plans for the next generation of liquid argon experiments: the short baseline (SBN) and the long baseline (DUNE) are on the horizon. The LAr TPC evolved from the bubble chambers preserving the high resolution of tracking. Data analysis requires automatic event reconstruction that can understand and efficiently use the high granularity images provided by detector. The talk will cover the most recent advances in the reconstruction techniques, and also possible ways of developments since we are still on the way towards the ultimate tool for the optimal data analysis.
396. RIKEN Lunch Seminar
"Neural Engineering, Healing the Brain Through Electromagnetic Stimulation"
Presented by Adam Lichtl, Delta Brain, Inc.
Thursday, November 5, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Daniel Pitonyak
397. Condensed-Matter Physics & Materials Science Seminar
"Pixelated detection in Differential Phase Contrast Interesting properties of pixelated STEM"
Presented by Matus Krajnak, University of Glasgow, United Kingdom
Thursday, November 5, 2015, 11 am
Bldg.480 Conf. Rm
Hosted by: Yimei Zhu
The application of differential phase contrast (DPC) imaging to the study of polycrystalline magnetic thin films and nanostructures in scanning transmission electron microscopy (STEM) has been hampered by the strong diffraction contrast resulting from the granular structure of the materials. In my talk I will demonstrate how a pixelated detector has been used to detect the bright field disk in aberration corrected STEM. I will explain subsequent processing of the acquired data, which allows efficient enhancement of the magnetic contrast in the resulting images. Initial results from a charged coupled device (CCD) camera demonstrate the highly efficient nature of this improvement over previous methods. Further hardware development with the use of a direct radiation detector, the Medipix3, also shows the possibilities where the reduction in collection time is more than an order of magnitude compared to the CCD. This allows subpixel measurement of the beam deflection due to the magnetic induction. Whilst the detection and processing is data intensive we have demonstrated highly efficient DPC imaging whereby pixel by pixel interpretation of the induction variation is realised with great potential for nanomagnetic imaging. In my talk I will also show advantages of using pixelated DPC in imaging of magnetic skyrmion structures in single crystal FeGe helimagnet which can provide their inner structure. I will advocate for pixelated STEM and explain how advantageous it can be in standard experiments and point to some new developments which it can provide.
"On the Development, Characterization, and Application of New Extraction Chromatographic Resins"
Presented by Dr. Steffen Happel, TRISKEM
Monday, November 2, 2015, 4 pm
Bldg. 911B, Large Conf. Rm. Rm.A202
Hosted by: Dmitri Medvedev
«An overview will be given over a number of new extraction chromatographic resins that have been developed over the last few years. Further to characterisation data (mainly DW values of selected elements) their application in various domains will be discussed. Examples given will include decommissioning and radioactive waste monitoring (e.g. Cl-36/I-129 and Sn-126), environmental monitoring (e.g. direct extraction and separation of Pb and Sr from aqueous samples) and the production of isotopes for medical purposes (e.g. production of Cu isotopes from Ni or Zn targets, the separation of Zr from Y targets and the separation of Sn from large Cd targets)."
399. Nuclear Theory/RIKEN Seminar
"Observable consequences of event-by-event fluctuations of HBT radii"
Presented by Christopher J. Plumberg, Ohio State University
Friday, October 30, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
One of the major lessons from the field of heavy-ion physics in the past several years has been the significance of the role played by event-by-event fluctuations in the evolution of a heavy-ion collision. Their important effects on many momentum-space observables (particle yields and spectra, anisotropic flows, etc.) have already been studied systematically, and some of the properties of their event-by-event distributions, and their consequences for the extraction of medium properties such as the specific viscosity of the quark-gluon plasma (QGP), are already known. In this talk it is pointed out that similar event-by-event fluctuations of spatiotemporal observables provide complementary constraints on our understanding of the dynamical evolution of heavy-ion collisions. The relation of Hanbury Brown-Twiss (HBT) radii extracted from ensemble-averaged correlation function measurements to the mean of their event-by-event probability distribution is clarified, and a method to experimentally determine the mean and variance of this distribution is proposed and demonstrated using an ensemble of fluctuating events generated with the viscous hydrodynamic code VISH2+1. The sensitivity of the mean and variance of the HBT radii to the specific QGP shear viscosity η/s is studied using simulations with the same code. We report sensitivity of the mean pion HBT radii and their variances to the temperature dependence of η/s near the quark-hadron transition at a level similar (10-20%) to that which was previously observed for elliptic and quadrangular flow of charged hadrons.
400. Condensed-Matter Physics & Materials Science Seminar
"The Internal Structure of a Vortex in a Two-Dimensional Superfluid with Long Healing Length"
Presented by Igor Aleiner, Columbia University
Thursday, October 29, 2015, 2 pm
Bldg. 734, ISB Conf. Rm. 201
Hosted by: Alexei Tsvelik
We analyze the motion of quantum vortices in a two-dimensional bosonic superfluid within Popov's hydrodynamic description. In the long healing length limit (where a large number of particles are inside the vortex core) the superfluid dynamics is determined by saddle points of Popov's action, which, in particular, allows for weak solutions of the Gross-Pitaevskii equation. We solve the resulting equations of motion for a vortex moving with respect to the superfluid and find the reconstruction of the vortex core to be a non-analytic function of the force applied on the vortex. This response produces an anomalously large dipole moment of the vortex and, as a result, the spectrum associated with the vortex motion exhibits narrow resonances lying {\em within} the phonon part of the spectrum, contrary to traditional view. (in collaboration with O. Agam and A. Klein)
401. Condensed-Matter Physics & Materials Science Seminar
"MITs, magnetism, and dopants: Probing the nanoscale using advanced STEM"
Presented by Jack Y. Zhang, University of California Santa Barbara
Thursday, October 29, 2015, 11 am
Bldg.480 Conf. Rm
Hosted by: Yimei Zhu
Perovskite oxides remain a material class with properties that are still difficult to predict. Strong electron correlations, coupling between electron, lattice, spin and orbital degrees of freedoms, combined with the versatility of the structure itself, result in a wide range of properties and unique emergent phenomena that only occur at heterointerfaces. Understanding the origin of these properties is the first step to successfully control and tailor these materials for useful application. To that end, we utilize the scanning transmission electron microscope to characterize a number of titanate and nickelate compounds, in order to develop a link between the atomic structure and electrical/magnetic properties. Using real-space and diffraction techniques, we can probe the local atomic structures of thin film interfaces and quantum wells. We also continue the development of using quantitative STEM intensities for precise and accurate determination of 3D dopant atom configurations. Using variable detector angles, we demonstrate an improvement in 3D dopant locations on a test sample.
402. HET/RIKEN Seminar
"N-jettiness subtraction scheme"
Presented by Xiaohui Liu, University of Maryland
Wednesday, October 28, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Cen Zhang
403. Nuclear Theory/RIKEN Seminar
"Thermal photons from a modern hydrodynamical model of heavy ion collisions"
Presented by Jean-Francois Paquet, Stonybrook University
Friday, October 23, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Early fluid-dynamical calculations of direct photon spectra and momentum anisotropy were found to be systematically smaller than measurements from the RHIC and the LHC, an observation that became known as the "direct photon puzzle". I will show that the use of a modern hydrodynamical model of heavy ion collisions and of the latest photon emission rates greatly improves agreement with both ALICE and PHENIX data, supporting the idea that thermal photons are the dominant source of direct photon momentum anisotropy in heavy ion collisions. The event-by-event hydrodynamical model used includes, for the first time, both shear and bulk viscosities, along with second order couplings between the two viscosities. Calculations using different photon emission rates will be shown, including one that takes into account the effect of confinement on photon emission. The effect of both shear and bulk viscosities on the photon rates will be shown to have a measurable effect on the photon momentum anisotropy.
404. HET/RIKEN Lunch Seminar
"Lattice QCD applications to inclusive tau decays and related topics"
Presented by Taku Izubuchi, BNL
Friday, October 23, 2015, 12 pm
Building 510 Room 2-160
Hosted by: Amarjit Soni
405. Particle Physics Seminar
"Light Sterile Neutrinos: An Experimental Overview"
Presented by Jonathan Link, Center for Neutrino Physics, Virginia Tech
Thursday, October 22, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Elizabeth Worcester
Persistent, unproven hints of an eV-scale sterile neutrino have been around since the late 1990's, when the LSND signal was shown to be incompatible with the emerging 3-neutrino oscillation framework. More recent results from MiniBooNE and T2K as well as reanalyses of reactor neutrino and gallium source data continue to suggest the possibility of this new physics, but no experiment has been able to definitively demonstrate or for that matter rule out their existence. This talk will review the current state of the sterile neutrino and examine one possible experimental test using a new reactor neutrino detector technology designed to address the particular challenges of a short-baseline reactor neutrino experiment.
406. RIKEN Lunch Seminar
"Walking and conformal dynamics in many-flavor QCD"
Presented by Hiroshi Ohki, RIKEN BNL Research Center
Thursday, October 22, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Tomomi Ishikawa
We present our lattice results of SU(3) gauge theory with many flavors, in particular with Nf=8, as a model of a walking or conformal gauge theory. We study the scaling properties of various hadron spectra including the (pseudo)scalar, vector, and baryon channels. From the Nf dependence of the theory, possible signals of walking or conformal dynamics will be discussed.
407. HET/RIKEN Seminar
"Phenomenology of semileptonic B-meson decays with form factors from lattice QCD"
Presented by Ran Zhou, Fermilab
Wednesday, October 21, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Tomomi Ishikawa
The exclusive semileptonic $B$-meson decays $B\to K(\pi)\ell^+\ell^-$, $B \to K(\pi)\nu\bar\nu$, and $B\to\pi\tau\nu$ are used to extract the CKM elements and probe new physics beyond Standard Model. The errors of the form factors used to be an important source of the uncertainties in the theoretical predictions. Recent developments in lattice-QCD provide more accurate form factors and enable us to have better theoretical predictions. In this talk, I will present the latest lattice-QCD results of the form factors in the semileptonic $B$-meson decays processes. In addition, I will compare the theoretical predictions and recent experimental results. The tension between the Standard Model and semileptonic $B$-meson decay experimental data will be discussed.
408. Condensed-Matter Physics & Materials Science Seminar
"Three dimensional topological semimetal Cd3As2: insights from magneto-optical spectroscopy"
Presented by Ana Akrap, University of Geneva, Switzerland
Wednesday, October 21, 2015, 1:30 pm
Bldg. 480 Conf. Room
Hosted by: Chris Homes
Cd3As2 is a three-dimensional Dirac semimetal, with two Dirac cones around the Gamma point shifted away from each other along the (001) direction. It is known that the Dirac cones appear due to band inversion, although their exact scale is not clear at the moment. I will talk about zero-field optical conductivity, and high-field magneto-reflectivity of this material, and address some of the open questions regarding the band structure.
409. Condensed-Matter Physics & Materials Science Seminar
"TBA"
Presented by Sasa Dordevic, University of Akron
Tuesday, October 20, 2015, 1:30 pm
Building 734, Room 201
Hosted by: Cedomir Petrovic
Infrared and magneto-optical studies of topological insulators Spectroscopic techniques are an important tool in studies of novel materials. I will review recent infrared and magneto-optical studies of 3D topological insulators Bi2Se3, Bi2Te3, Sb2Te3 and Bi1-xSbx. A number of issues will be discussed, such as the cyclotron resonance and its field dependence, electronic inhomogeneities, and electron-phonon coupling. We find that in Bi2Se3 charge carriers are indeed strongly coupled to an optical phonon, causing its asymmetric (Fano) lineshape. Moreover, we show that the asymmetry of the phonon can be switched from negative to positive, with the application of magnetic field. This is the so-called Fano q reversal, which to the best of our knowledge has not been observed before in topological insulators.
410. Condensed-Matter Physics & Materials Science Seminar
"GW+DMFT: a diagrammatically controlled ab initio theory of strong correlation in real materials"
Presented by Sangkook Choi, Rutgers University
Tuesday, October 20, 2015, 11 am
Building 734, Room 201
Hosted by: Robert Konik
The first principles description of strongly-correlated materials is currently regarded as one of the greatest challenges in condensed matter physics. In contrast to the weakly-correlated materials, one-particle picture based on the Fermi liquid theory fails because electrons in strongly-correlated materials are neither fully localized on the atomic sites nor fully itinerant in the crystal. One of the most successful approaches to strongly-correlated materials is the dynamical mean field theory (DMFT). Its successes revived the interest in the long-sought goal of achieving a diagrammatically controlled ab initio theory by combining GW and DMFT Feynman graphs. In this talk, I'll introduce GW+DMFT approaches and present our new methodology grounded on the combination of the quasiparticle self-consistent GW approximation (QSGW) and DMFT. I will also show how QSGW+DMFT approach improves the spectral properties of open-d and -f shell systems in comparison to other theories. I will conclude with the challenges ahead and its potential roles in materials design.
411. Nuclear Theory/RIKEN Seminar
"Next-to-leading order JIMWLK from wave function formalism"
Presented by Yair Mulian, Ben Gurion University of the Negev
Friday, October 16, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
412. Particle Physics Seminar
"Recent Results from the BaBar Experiment"
Presented by David Norvil Brown, University of Louisville
Thursday, October 15, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Ketevi A. Assamagan
The BaBar Experiment was initially designed to study CP-Violation in B-meson decays. However, due to the general-purpose and high-quality design of the detector, it has been utilized for studies of many topics beyond the weak flavor realm. I will present a selection of recent results from BaBar, including topics from B physics and beyond. The results selected include a first observation of a mode which is an interesting piece in the puzzle about baryonic B-meson decays; a measurement of time-dependent asymmetries in a B-meson decay; a measurement of Collins asymmetries in u, d, and s quark fragmentation; and a search for long-lived particles predicted in many beyond the Standard Model theories.
413. Condensed-Matter Physics & Materials Science Seminar
Presented by Sergey Zvyagin, High Magnetic Field Laboratory, Helmholtz Center Dresden, Germany
Thursday, October 15, 2015, 1:30 pm
Building 734, Room 201
Hosted by: Cedomir Petrovic
Spin dynamics in triangular-lattice antiferromagnets Cs2CuBr4 and Cs2CuCl4: high-field ESR studies Sergei Zvyagin Dresden High Magnetic Field Laboratory (HLD) Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany A spin-1/2 Heisenberg antiferromagnet (AF) on a triangular lattice is the paradigmatic model in quantum magnetism and in the focus of recent experimental and theoretical studies. Here, we present results of high-field electron spin resonance (ESR) studies of spin-1/2 Heisenberg AFs Cs2CuCl4 and Cs2CuBr4 with distorted triangular-lattice structures in magnetic fields up to 50 T [1]. In the magnetically saturated phase, quantum fluctuations are fully suppressed, and the spin dynamics is defined by ordinary magnons. This allows us to accurately describe the magnetic excitation spectra in both materials and, using the harmonic spin-wave theory, to determine their exchange parameters. The approach has a broader impact and can be potentially used for any quantum magnet with reduced (e.g., by the staggered Dzyaloshinskii-Moriya interaction) translational symmetry, resulting, as predicted, in emergence of a new exchange mode above Hsat. We found that a substantial zero-field energy gap, Î"~9.5 K, observed in the low-temperature excitation spectrum of Cs2CuBr4, is present below and well above TN, being a characteristics of low-dimensional spin-correlated state. The experimental data are compared with results of model spin-wave-theory calculations for spin-1/2 triangular lattice AF. This work was supported by the DFG. [1] S. A. Zvyagin, D. Kamenskyi, M. Ozerov, J. Wosnitza, M. Ikeda, T. Fujita, M. Hagiwara, A. I. Smirnov, T. A. Soldatov, A. Ya. Shapiro, J. Krzystek, R. Hu, H. Ryu, C. Petrovic, and M. E. Zhitomirsky, Phys. Rev. Lett. 112, 077206, 2014
414. RIKEN Lunch Seminar
"pQCD thermodynamics with massive quarks"
Presented by Thorben Graf, Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität
Thursday, October 15, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Daniel Pitonyak
Results for several thermodynamic quantities within the next-to-leading order calculation of the thermodynamic potential in perturbative QCD at finite temperature and chemical potential including non-vanishing quark masses are presented. These results are compared to lattice data and to higher-order optimized perturbative calculations to investigate the trend brought about by mass corrections. Furthermore, the equation of state for nonvanishing isospin density was investigated within the introduced framework and the findings are also presented.
415. Physics Colloquium
"Random Matrices in Physics"
Presented by Hans A. Weidenmuller, Max-Planck-Institut fur Kernphysik, Heidelberg, Germany
Tuesday, October 13, 2015, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Robert Pisarski
What can we say about a physical system when we know next to nothing about it? In classical physics, the principles of thermodynamics and a few system-specific parameters suffice to make predictions. In quantum physics, random matrices have similar predictive power. That approach-referred to as random-matrix theory-has found wide applications in recent years, in quantum physics and beyond. The use of random matrices in quantum chaos, in complex many-body systems, in disordered systems and in quantum chromodynamics will be presented. Furher applications in physics and mathematics will be briefly mentioned.
416. Special Nuclear Theory Seminar
"Inclusive Hadron Production as a Probe of Saturation Physics on the Energy Frontier"
Presented by David Zaslavsky, Central China Normal University
Friday, October 9, 2015, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
With a foundation of almost two decades of theoretical research, the saturation formalism is widely considered a strong candidate to describe the behavior of small-x gluons in high-energy collisions. However, the formalism has proven difficult to test. There is a pressing need for precise numerical results from the saturation formalism to use in comparisons with collider data. Fortunately, recent progress in the cross section for inclusive hadron production in pA collisions shows that it may be just the kind of precise result the community needs. The calculation of the NLO corrections, starting in 2012, achieved impressive reductions in the theoretical and numerical uncertainties, although the result becomes negative at high p⊥. Still, precise predictions at moderate p⊥ can be made and tested, and could be strong evidence toward showing the viability of the saturation model. In this talk, I introduce the recent modifications to the dipole splitting functions that complete the NLO corrections and help offset the negativity observed in earlier results. I'll also present the latest numerical results for the full LO+NLO cross section, including the first comparison with LHC pilot run data. For forward rapidity at both RHIC and the LHC, we have found excellent agreement with the data throughout the range in which the calculation is valid.
417. Condensed-Matter Physics & Materials Science Seminar
"TBATopological Nodal-Line Fermions in Strong Spin-Orbit Metal PbTaSe2"
Presented by Tay-Rong Chang, National Tsing Hua University Taiwan, Taiwan
Thursday, October 8, 2015, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: Wei Ku
In a typical three-dimensional metal, the low-energy excitations are found on a two-dimensional closed Fermi surface in momentum space. Topological semimetals, by contrast, can support one-dimensional Fermi lines or zero-dimensional Fermi-Weyl points, at locations in momentum space, where the valence and conduction bands touch. While the degeneracy points in Weyl semimetals are robust against any perturbation that preserves translational symmetry, nodal lines require protection by additional crystalline symmetries such as mirror reflection. In this talk, I will demonstrate the prediction of topological nodal-line states in the non-centrosymmetric compound single-crystalline PbTaSe2 with strong spin-orbit coupling based on the first-principles electronic structure calculations. Remarkably, the spin-orbit nodal lines in PbTaSe2 are not only protected by the reflection symmetry but also characterized by an integer topological invariant. Our theoretical analysis illustrate the physical mechanism underlying the formation of the topological nodal-line states and associated surface states. The calculated surface states for (001) surface with Pb-termination are in good agreement with angle-resolved photoemission (ARPES) measurements [1]. [1] arXiv:1505.03069, G. Bian, T.-R. Chang, R. Sankar, et al.
418. Particle Physics Seminar
"Top Quark Precision Physics and the Fate of the Universe"
Presented by Andreas Jung, Purdue University
Thursday, October 1, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Ketevi A. Assamagan
The talk will discuss recent measurements in the top quark sector, the heaviest known elementary particle known so far, performed at the Fermilab Tevatron Collider and at the LHC. I will highlight Tevatron results that are competitive to those at the LHC, especially regarding the top quark mass and production asymmetry. The talk will also present CMS results on the top quark mass and Yukawa coupling. I will discuss the implications for the standard model electroweak sector regarding the vacuum stability. I will conclude with an outlook towards the high luminosity phase of the LHC and the CMS silicon detector upgrades required for the high luminosity phase.
419. Particle Physics Seminar
"Recent Results From Daya Bay"
Presented by Gaosong Li, Shanghai Jiao Tong University
Monday, September 28, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Elizabeth Worcester
The Daya Bay Reactor Neutrino Experiment is designed to measure the neutrino mixing angle ï±13 with unprecedented precision. The experiment utilizes multiple pairs of identical antineutrino detectors (ADs) at different baselines from three pairs of reactor cores to minimize systematic uncertainties. In 2012, Daya Bay made the first definitive measurement of a non-zero value for ï±13 using the first 55 days of data collected with six ADs by measuring the antineutrino rate deficit. With the final two ADs installed, Daya Bay resumed data taking in full 8-AD configuration in late 2012. More than 1 (0.15) million electron antineutrino candidates had been collected with the near (far) site detectors by the end of 2013, significantly improving the precision on ï±13. In addition to precision measurement of neutrino oscillation parameters, analyses exploring various other physics potential are carried out. In this talk, I will present the latest results on neutrino oscillation parameters, the search for a light sterile neutrino and the measurement of reactor neutrino flux and spectrum.
420. Condensed-Matter Physics & Materials Science Seminar
"Inelastic Neutron Scattering of Manganese Pnictide Compounds LaMnPO and CaMn2Sb2"
Presented by Daniel McNally, Stony Brook University/BNL
Monday, September 28, 2015, 11 am
Bldg. 480
Hosted by: Mark Dean
I will report on two different projects that used inelastic neutron scattering measurements to determine 1. The origin of the charge gap in LaMnPO [1] 2. The origin of the magnetic frustration in CaMn2Sb2 [2] 1. I present my inelastic neutron scattering measurements over a wide range of temperatures on a powder sample of the antiferromagnetic insulator LaMnPO, that exhibits long range antiferromagnetic order below TN = 375 K. I used these measurements to determine a) the strength of the inter-site magnetic exchange interactions SJ1 = 34 meV, SJ2 = 10 meV b) the temperature Tmax = 700 K (>> TN) where 2D magnetic correlations are no longer important. I then present high temperature optical spectroscopy measurements on single crystals of LaMnPO that show a charge gap persists above TN and Tmax. These experimental results show that long range magnetic order and exchange interactions play only a limited role in the formation of the charge gap in LaMnPO. Instead, density functional theory plus dynamical mean field theory calculations show that Hund's coupling is critical for the formation of the charge gap in LaMnPO, as well as related square net Mn pnictide compounds such as BaMn2As2 [D.E. McNally et al. PRB 92 115142 (2015)]. I will show that this work supports the view that multi-orbital electronic correlations are important in the isostructural iron pnictide based superconductors. 2. I present my inelastic neutron scattering measurements on single crystals of the antiferromagnetic insulator CaMn2Sb2, that forms a corrugated honeycomb lattice of Mn spins that order below TN = 85 K, rather low for a Mn pnictide compound. I observed sharp dispersive 3D spin wave excitations up to energy transfers of 25 meV. I used a Heisenberg model to analyze the excitations and determine the first, second and c-axis exchange interactions J1, J2, Jc. I use the determined ratio J2/J1 = 0.17 to situate CaMn2Sb2 on the theoretical phase diagram of the ho
421. ATLAS/HET Joint Lunch Seminar
"Constraints on New Physics via Higgs Boson Couplings and Invisible Decays with the ATLAS Detector"
Presented by Ketevi Assamagan, Brookhaven National Laboratory
Friday, September 25, 2015, 12 pm
Building 510 Room 2-160
Hosted by: Amarjit Soni
The ATLAS experiment at the LHC has measured the Higgs boson couplings and mass, and searched for invisible Higgs boson decays, using multiple production and decay channels with up to 4.7 fb$^{-1}$ of $pp$ collision data at $\sqrt{s}=7$ TeV and 20.3 fb$^{-1}$ at $\sqrt{s}=8$ TeV. In the current study, the measured production and decay rates of the observed Higgs boson in the $\gamma\gamma$, $ZZ$, $WW$, $Z\gamma$, $bb$, $\tau\tau$, and $\mu\mu$ decay channels, along with results from the associated production of a Higgs boson with a top-quark pair, are used to probe the scaling of the couplings with mass. Limits are set on parameters in extensions of the Standard Model including a composite Higgs boson, an additional electroweak singlet, and two-Higgs-doublet models. Together with the measured mass of the scalar Higgs boson in the $\gamma\gamma$ and $ZZ$ decay modes, a lower limit is set on the pseudoscalar Higgs boson mass of $m_{A}>370$ GeV in the hMSSM'' simplified Minimal Supersymmetric Standard Model. Results from direct searches for heavy Higgs bosons are also interpreted in the hMSSM. Direct searches for invisible Higgs boson decays in the vector-boson fusion and associated production of a Higgs boson with $W/Z$ ($Z\to ll$, $W/Z \to jj$) modes are statistically combined to set an upper limit on the Higgs boson invisible branching ratio of 0.25. The use of the measured visible decay rates in a more general coupling fit improves the upper limit to 0.23, constraining a Higgs portal model of dark matter.
422. Condensed-Matter Physics & Materials Science Seminar
"Single-atom Impurity Effects in Iron-based Superconductors"
Presented by Shuheng H. Pan, Institute of Physics, Chinese Academy of Sciences
Friday, September 25, 2015, 11 am
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: Yimei Zhu
Impurities can break Cooper-pairs into quasi-particles with energy states inside the superconducting gap. The characteristics of such in-gap states reflect accordingly the properties of the superconducting ground state. Therefore, impurity effects in superconductors have always been important subjects in the fundamental study of superconductivity. A single-atom impurity is an ideal model for both experimental and theoretical study of impurity effects on superconductivity. With high resolution STM/S technique, such proposal has been successfully realized. In this talk, I will present some of our high resolution STM/S studies of single-atom impurity effects in iron-based superconductors and discuss their implications to the microscopic mechanism of iron-based superconductivity.
423. Particle Physics Seminar
"Time Delay Cosmology"
Presented by Eric Linder, Berkeley/LBNL
Thursday, September 24, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Anze Slosar
Thousands of strong gravitational lenses will be found by time domain surveys such as DES and LSST. Time delays between multiple images can be used to form a geometric time delay distance, a cosmological probe with some unique sensitivities and complementarities. I consider three aspects: 1) the cosmology impact, 2) the statistics challenge of accurate estimation of time delays between noisy, gappy lightcurves and recent results from LSST's blind Time Delay Challenge, and 3) optimization of limited followup resources. I will also present new theory and instrument concepts for cosmic redshift drift, a direct probe of cosmic acceleration with a Hubble time delay. Methods for both probes have interesting overlaps with exoplanet searches.
424. Condensed-Matter Physics & Materials Science Seminar
"A Giant Phonon Anomaly associated with Superconducting Fluctuations in the Pseudogap Phase of Cuprates"
Presented by Yehua Liu, ETH, Switzerland
Thursday, September 24, 2015, 1:30 pm
Bldg 734, 2nd Fl Conference Room
Hosted by: Robert Konik
Recent observations of a Giant Phonon Anomaly at the onset of the pseudogap, has revealed another surprising property of this phase. The opening of the pseudogap in underdoped cuprates breaks up the Fermi surface, which in turn can cause a breakup of the superconducting d-wave order parameter into two subband amplitudes and to a low energy Leggett mode due to phase fluctuations between them. This leads to a large increase in the temperature range of superconducting fluctuations due to an overdamped Leggett mode. Almost resonant scattering of intersubband phonons to a state with a pair of Leggett modes, causes anomalously strong phonon damping. In the ordered state, the Leggett mode develops a finite energy, suppressing the anomalous phonon damping but leading to an anomaly in the phonon dispersion.
425. HET/RIKEN Seminar
"The Surprising Emergent Phenomena of Perturbative QCD"
Presented by Andrew J. Larkoski, MIT
Wednesday, September 23, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Cen Zhang
426. Nuclear Theory/RIKEN Seminar
"Single inclusive particle production at NLO: revised and improved"
Presented by Alex Kovner, University of Connecticut
Friday, September 18, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
We discuss the recent improvement of the NLO calculation of single inclusive particle production in pA collisions within the CGC formalizm. The two points that have not been addressed previously, and are treated consistently in the current approach are the Ioffe time cutoff on the configurations that can participate in the scattering, and the careful treatment of the evolution interval.
427. Particle Physics Seminar
"CMB Constraints DM Annihilation/Sum of the neutrino masses from CMB observations"
Presented by Neelima Sehgal, Stony Brook University
Thursday, September 17, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Ketevi Assamagan
I will present the latest constraints on the properties of annihilating dark matter and on the sum of the neutrino masses from CMB observations. I will focus on what has been learned so far from the Planck satellite and current ground-based CMB experiments. I will also discuss what we can expect in the future in terms of constraining dark matter and neutrino properties from near-future ground-based experiments, such as Advanced ACTPol, and the planned DOE CMB-S4 project.
428. Condensed-Matter Physics & Materials Science Seminar
"Atomic spin chain realization of a model for quantum criticality"
Presented by Rianne van den Berg, Universiteit van Amsterdam, Netherlands
Thursday, September 17, 2015, 1:30 pm
Bldg 734, 2nd Fl Conference Room
Hosted by: Robert Konik
The ability to manipulate single atoms has opened up the door to constructing interesting and useful quantum structures from the ground up. On the one hand, nanoscale arrangements of magnetic atoms are at the heart of future quantum computing and spintronic devices; on the other hand, they can be used as fundamental building blocks for the realization of textbook many-body quantum models, illustrating key concepts such as quantum phase transitions, topological order or frustration. Step-by-step assembly promises an interesting handle on the emergence of quantum collective behavior as one goes from one, to few, to many constituents. To achieve this, one must however maintain the ability to tune and measure local properties as the system size increases. We use low-temperature scanning tunneling microscopy to construct arrays of magnetic atoms on a surface, designed to behave like spin-1/2 XXZ Heisenberg chains in a transverse field, for which a quantum phase transition from an antiferromagnetic to a paramagnetic phase is predicted in the thermodynamic limit. Site-resolved measurements on these finite size realizations reveal a number of sudden ground state changes when the field approaches the critical value, each corresponding to a new domain wall entering the chains. We observe that these state crossings become closer for longer chains, indicating the onset of critical behavior. Our results present opportunities for further studies on quantum behavior of many- body systems, as a function of their size and structural complexity.
"Attainment of Electron Beam Suitable for Medium Energy Electron Cooling"
Presented by Dr. Sergei Seletskiy, BNL-Photon Science
Thursday, September 17, 2015, 11 am
Bldg 911B, Large Conf. Rm., Rm A202
""The Recycler Electron Cooler (REC) at Fermilab advanced the electron cooling to the MeV-range energies. The REC performance depended critically on the quality of electron beam. In my presentation I will describe various aspects of development of the REC and the techniques used to obtain the electron beam suitable for the cooling process."
430. Nuclear Theory/RIKEN Seminar
"The equation of state of QCD at finite temperature and chemical potential(s)"
Presented by Michael Strickland, Kent State University
Friday, September 11, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
431. Center for Functional Nanomaterials Seminar
"Fluctuation Electron Microscopy â€" probing higher order structural correlations in disordered materials by coherent diffraction Soft Matter Enhanced Electrochemical Energy Storage and 3D Photonic Crystals"
Presented by J. Murray Gibson, Department of Physics, Northeastern University, Boston
Thursday, September 10, 2015, 11 am
CFN, Building 735, 2nd floor - Seminar Conf. Rm.
Hosted by: Eric Stach
Center for Functional Nanomaterials J. Murray Gibson Department of Physics, Northeastern University, Boston Fluctuation Electron Microscopy â€" probing higher order structural correlations in disordered materials by coherent diffraction Soft Matter Enhanced Electrochemical Energy Storage and 3D Photonic Crystals Thursday, September 10, 2015 11:00 a.m. Seminar Room, 2nd Fl. The conventional pair-correlation function, measured directly from diffraction, is a powerful tool to measure short-range order on the scale of chemical bonds and next neighbors. With sufficiently well-defined long range order, the 2-body function clearly reveals symmetry and periodicity. Diffraction techniques have thus been incredibly successful at the short-range in teaching us about the structure of liquids and amorphous solids, and at the other scale most of what we know about the crystalline structure of matter. However the 2-body function has a potential "blind spot" for ordering at intermediate length scales, typically up to of order ten bond lengths. Studies of amorphous materials by other techniques suggest that there can be pronounced medium-range ordering on the nanoscale and that it can significantly affect physical properties. It is now recognized that higher-order correlation functions (3 and 4 body) are far more sensitive to medium-range order and that that they can be accessed experimentally from coherent diffraction experiments. One of the earliest techniques to examine this was fluctuation microscopy (FM), developed by Treacy and Gibson1 for electron microscopy (FEM) and applied early to demonstrate medium-range order and the effect of annealing in amorphous germanium2. In more recent years, with the freer access to coherent sources of electrons and x-rays, more people are using FEM and developing related techniq
"Multipass Energy Recovery Experiment at Jefferson Lab's CEBAF"
Presented by Dr. Todd Satogata, JLAB
Wednesday, September 9, 2015, 4 pm
Bldg. 911A, Snyder Seminar Room
"The CEBAF recirculating linac accelerator has recently completed 12 GeV upgrade development, and plans to commission full energy accelerator setup this fall. With upgrade commissioning nearly complete, there is a new collaboration between BNL and Jefferson Lab that is developing a proposal for a multi-pass energy recovery experiment. This talk summarizes the current state of 12 GeV CEBAF, technical challenges for multi-pass energy recovery, and collaboration goals and technical progress for this multi-pass energy recovery experiment."
433. Joint Nuclear Physics and Particle Physics Seminar
"Understanding the nature of neutrinos via neutrinoless double-beta decay"
Presented by Wenqin Xu, Los Alamos National Laboratory
Tuesday, September 8, 2015, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Jin Huang
Neutrinos provide a critical portal to physics beyond the Standard Model, yet the nature of neutrinos is largely unknown, including the neutrino mass hierarcy and if neutrinos are Majorana particles. Majorana particles are fermions that are their own antiparticles. Neutrinos being Majorana particles would explicitly violate lepton number conservation, and would pave the way to understand the matter-antimatter asymmetry in the universe. Neutrinoless double-beta (0 ) decay is a hypothesized process where two neutrons decay into two protons and two electrons simultaneously without emitting neutrinos. It is possible only if neutrinos are Majorana particles, and it is the only feasible way to experimentally establish the Majorana or Dirac nature of neutrinos. The observation of 0 decay would also provide complementary information related to neutrino masses. After decades of experimental e orts, the next generation 0 decay experiments will have a signi cant discovery potential to observe 0 decay, if neutrinos are indeed Majorana particles. In this talk, we will discuss the physics of neutrinoless double beta decay and review the experiments searching for it. We will focus on the Majorana Demonstrator, a 40-kg modular Germanium detector array, which searches for 0 decay in 76Ge and aims at demonstrating a path forward to next generation 0 decay experiments.
434. Nuclear Theory/RIKEN Seminar
"Asymptotic freedom of gluons in the Fock space"
Presented by Stanislaw Glazek, University of Warsaw
Friday, September 4, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Asymptotic freedom of gluons is defined in terms of scale-dependent renormalized QCD Hamiltonian operators that act in the Fock space. These operators are calculable in a new way [1,2], by solving a double-commutator differential equation [3], where the derivative is with respect to a scale parameter defined within the renormalization group procedure for effective particles (RGPEP). The RGPEP equation and its solutions are invariant with respect to boosts and may serve as a tool in attempts to dynamically explain the parton and constituent models of hadrons in QCD. The third-order QCD solution of the RGPEP equation to be discussed [2], provides an explicit example of how asymptotic freedom of gluons is exhibited in the scale-dependence of Hamiltonians as operators in the Fock space. This example also prepares ground for the fourth-order calculations of effective strong interactions using the same RGPEP equation [3], to facilitate Hamiltonian studies of many strong-interaction processes, e.g., those that involve heavy quarkonia in relativistic motion. Applications to other sectors of the Standard Model than the strong interactions await development, while only preliminary results are currently available in the domain of precise calculations in QED[4]. [1] Dynamics of effective gluons, S. D. Glazek, Phys. Rev. D63, 116006, 29p (2001). [2] Asymptotic freedom in the front-form Hamiltonian for gluons, M. Gomez-Rocha, S. D. Glazek, arXiv:1505.06688 [hep-ph], to appear in Phys. Rev. D. [3] Perturbative formulae for relativistic interactions of effective particles, S. D. Glazek, Acta Phys. Pol. B43, 1843, 20p (2012). [4] Calculation of size for bound-state constituent
435. RIKEN Lunch Seminar
"Analytic solution of the Boltzmann equation in the early universe"
Presented by Jorge Noronha, University of Sao Paulo
Thursday, September 3, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Daniel Pitonyak
A general method for exactly computing the nonlinear collision term of the Boltzmann equation for a massless relativistic gas in a homogeneous and isotropic spacetime is presented. This approach is used to find an exact analytical solution of the nonlinear relativistic Boltzmann equation in a Friedmann-Robertson-Walker spacetime. This solution can be used to investigate analytically the interplay between global expansion and local thermalization in rapidly evolving systems.
436. HET/RIKEN seminar
"Effective Field Theory of Heavy WIMP Annihilation"
Presented by Matthew Baumgart, Rutgers University
Wednesday, August 26, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Chien-Yi Chen
437. Nuclear Physics Seminar
"Orbital angular momentum and generalized transverse momentum distribution"
Presented by Mr. Yong Zhao, University of Maryland
Tuesday, August 25, 2015, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Oleg Eyser
Recent advances in theory have shown that it is possible to directly calculate the canonical quark and gluon orbital angular momentum contributions to the proton spin in lattice QCD. When boosted to the infinite momentum frame, the quark and gluon orbital angular momentum operators defined in the gauge-invariant nucleon spin sum rule of X. S. Chen et al. are the same as those derived from generalized transverse momentum distributions. The latter reduce to the canonical orbital angular momenta in the light-cone gauge, and can be measured in high-energy scattering experiments. I will show that these orbital angular momentum operators can be defined locally, and discuss the strategies of calculating their matrix elements in lattice QCD.
438. Special Nuclear Theory/RIKEN seminar
"Thermodynamics and topology from lattice QCD"
Presented by Michael Muller-Preussker, Humboldt University Berlin
Monday, August 24, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Recent efforts to investigate the thermodynamics of lattice QCD with N_f=2+1+1 fermion degrees of freedom at realistic strange and charm quark masses and at various up and down quark mass values within the framework of Wilson twisted mass fermion discretization are discussed. Comparing with recently published results in the N_f=2 case we are going to present results for the pseudo-critical temperature and preliminary results on the way to the thermodynamic equation of state. Moreover, we would like to discuss various methods to determine the topological susceptibility as a function of the temperature.
439. Center for Functional Nanomaterials Seminar
"Caught in the Act! Live Observations of Catalysts Using High-pressure Scanning Probe Microscopy"
Presented by Irene M. N. Groot, Leiden Institute of Physics and Leiden Institute of Chemistry, the Netherlands
Friday, August 21, 2015, 10 am
CFN, Bldg. 735, first fl. conference room A
Hosted by: Anibal Boscoboinik
Center for Functional Nanomaterials Seminar Caught in the Act! Live Observations of Catalysts Using High-pressure Scanning Probe Microscopy Irene M. N. Groot Leiden Institute of Physics and Leiden Institute of Chemistry, the Netherlands Friday, August 21, 2015 10:00 am Bldg. 735 â€" Conf. Rm. A Recently it has become clear that essential differences can exist between the behavior of catalysts under industrial conditions (high pressure and temperature) and the (ultra) high vacuum conditions of traditional laboratory experiments. Differences in structure, composition, reaction mechanism, activity, and selectivity have been observed. These observations indicated the presence of the so-called pressure gap, and made it clear that meaningful results can only be obtained at high pressures and temperatures. However, most of the techniques traditionally used to study catalysts and their reactions were designed to operate under (ultra) high vacuum conditions. To bridge the pressure gap, the last years have seen a tremendous effort in designing new instruments and adapting existing ones to be able to investigate catalysts in situ under industrially relevant conditions. This talk focuses on the development of scanning probe microscopy for operando observations of active model catalysts. In our group, we have developed set-ups that combine an ultrahigh vacuum environment for model catalyst preparation and characterization with a high-pressure flow reactor cell, integrated with either a scanning tunneling microscope or an atomic force microscope. With these set-ups we are able to perform atomic-scale investigations of well-defined model catalysts under industrial conditions. Additionally, we combine the structural information from scanning probe microscopy with time-resolved mass spectrometry measurements on the gas mixture that leaves the re
440. Particle Physics Seminar
"New Optical Techniques for Studying Vacuum Birefringence"
Presented by Carol Y. Scarlett, Florida A&M University
Thursday, August 20, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Elizabeth Worcester
The search for Axions, a particle theorized to explain the lack of CP violation in strong physics and suspected to contribute if not explain galactic dark matter, has lead to ever-sensitive techniques to study induced vacuum birefringence. What remains an issue: many of the measurable parameters that could give evidence for this illusive particle scale with the square of the birefringent angle (proportional to the photon-axion coupling constant). This talk will look at new techniques that can generate measurables that scale linearly (first order) with an induced birefringence. This has the potential to extend significantly the range through which cavity experiments can probe the vacuum of space in performing searches for axions and other exotic particles.
441. Computational Science Center Seminar
"High Performance Spatial Queries and Analytics for Spatial Big Data"
Presented by Fusheng Wang, SUNY SB
Tuesday, August 18, 2015, 10:30 am
John Dunn Seminar Room, Bldg. 463
Support of high performance queries and analytics on large volumes of spatial data becomes increasingly important in many application domains, including geospatial problems and emerging scientific applications such as pathology imaging. There are two major challenges for managing and querying massive spatial data: the explosion of spatial data, and the high computational complexity of spatial queries due to its multi-dimensional nature. Our goal is to develop a general framework to support high performance spatial queries and analytics for spatial big data on MapReduce and CPU-GPU hybrid platforms. In this talk, I will present a scalable and high performance spatial data warehousing system Hadoop-GIS for running large scale spatial queries on Hadoop and Spark. Hadoop-GIS achieves scalable and efficient queries through optimized spatial partitioning, multi-level indexing, customizable spatial query engine RESQUE and implicit parallel spatial query execution. I will introduce applications of the system to support pathology imaging analytics and social media analytics.
442. Nuclear Theory/RIKEN Seminar
"Initial state correlations, entanglement entropy and all that"
Presented by Michal Lublinsky, Ben Gurion University of the Negev
Friday, August 14, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
I will discuss high energy collisions of dilute on dense systems (pA) and review some ideas about initial-state induced correlations.
443. Particle Physics Seminar
"Exciting New Results From LHCb"
Presented by Sheldon Stone, Syracuse University
Thursday, August 13, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Elizabeth Worchester
LHCb has presented groundbreaking new results this summer in exotic particle spectroscopy and searches for new physics.
444. RIKEN Lunch Seminar
"Discrimination of large quantum ensembles"
Presented by Emilio Bagan, GIQ, Physics Dept., UAB, Spain and Hunter College of the CUNY
Thursday, August 13, 2015, 12:30 pm
Building 510, Room 2-160
Hosted by: Daniel Pitonyak
"Hypothesis testing is arguably the most common and elementary task in information processing (e.g., we constantly make decisions based on incomplete information). Its quantum version, quantum state discrimination, is likewise central in quantum information processing. The talk gives an introduction to the topic, focussing on discrimination of a large amount of identically prepared systems. In this limit, a powerful bound on the error rate can be derived. In classical statistics this is know as Chernoff bound. The quantum version of the Chernoff bound will be presented and discussed."
445. HET/RIKEN Seminar
"Constraining Extended Higgs Sectors at the LHC and Beyond"
Presented by Tania Robens, Technical University of Dresden
Wednesday, August 12, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Sally Dawson
446. Physics Colloquium
"Life after Physics: A look back on 20 years in Finance"
Presented by Andreas Gocksch
Tuesday, August 11, 2015, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Robert Pisarski
After 10 years of research in High Energy Theory this BNL graduate ('83-'85 and '88-'93) followed the call of Wall Street. In my talk I reflect on over 20 years in the financial industry with an emphasis on highlighting possible career choices for young people that might one day be faced with searching for a "life after Physics". Along the way I also hope to leave the audience with an understanding of some basic facts about Finance and an appreciation for the utility of the physicist's toolkit in the "real world". *This talk may be of especial interest to students.
447. Nuclear Theory/RIKEN seminar
"Inclusive Hadron Spectra: LHC data, fragmentation, towards NNLO, and all that"
Presented by Marco Stratmann, University of Tuebingen
Friday, August 7, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
448. HET/RIKEN seminar
"Higgs coupling deviations, vacuum stability and new bosons at the TeV scale"
Presented by Raffaele D'Agnolo, Institute for Advanced Study
Wednesday, August 5, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Chien-Yi Chen
Higgs coupling measurements can shed light on the nature of electroweak symmetry breaking. However it is not trivial to go beyond generic intuitions, such as the expectation that natural theories generate large deviations, and make precise statements. In this talk I will show in a model independent way that measuring deviations at the LHC implies the existence of new bosons between a few TeV and a few hundred TeV. This is true in general, including theories where new fermions produce the deviations.
449. Nuclear Theory/RIKEN seminar
"Generalized Landau-level representation for spin-1/2 fermions and its applications"
Presented by Igor Shovkovy, Arizona State University
Friday, July 31, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
I will discuss the recently proposed generalized Landau-level representation for charged fermions in an external magnetic field. After demonstrating its key advantages over the other existing representations, I will mention several of its applications. One of them is the quantum Hall effect in graphene, where the new representation is essential for a sufficiently detailed theoretical description, in which all the dynamical parameters are running functions of the Landau-level index. The other application is the chiral asymmetry induced in dense relativistic matter in an external magnetic field. The quantitative measure of such an asymmetry is the chiral shift parameter that measures a relative shift of the longitudinal momenta (along the direction of the magnetic field) in the dispersion relations of opposite chirality fermions. Using the language of solid state physics, the corresponding ground state of dense relativistic matter could be interpreted as a Weyl metal state. Incidentally, the exact same mechanism also works in real Dirac metals.
"Muon Accelerators: R&D Towards Future Neutrino Factory and Lepton Collider Capabilities"
Presented by Mark Palmer, Fermilab
Thursday, July 30, 2015, 3:30 pm
Building 911B, Large Conference Room, Second Floor
This talk will describe the evolution of Muon accelerator R&D. An overview of what has been accomplished under the U.S. Muon Accelerator Program (MAP), what remains to be done, and how the elements of the program are evolving will be presented.
451. RIKEN Lunch Seminar
"P-odd Spectral Density at Weak Coupling: Photon Emission and Second"
Presented by Ho-Ung Yee, University of Illinois at Chicago
Thursday, July 30, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Daniel Pitonyak
The P-odd spectral density of current correlation functions appears in several physical observables which are related to chiral anomaly, and is a sensitive probe of microscopic dynamics which is less protected by symmetry alone. We discuss two examples of their appearance: photon emission and the second order transport coefficient from chiral anomaly. We describe leading order weak coupling computations for these examples.
452. HET/RIKEN Seminar
"Probing Charm-Yukawa at LHC, Status and Prospects"
Presented by Kohsaku Tobioka, Weizmann Institute/Tel Aviv University
Wednesday, July 29, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Chien-Yi Chen
453. Physics Colloquium
"Exotic and conventional hadrons from lattice QCD"
Presented by Sasa Prelovsek, University of Ljubljana, Jefferson Lab
Tuesday, July 28, 2015, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Rob Pisarski
Faced with the recent experimental discoveries of pentaquarks and tetraquarks, one would like to establish whether these states arise directly from the fundamental theory of strong interactions - QCD. I will present how the exotic and conventional hadrons are investigated with ab-initio lattice QCD simulations. The approach will be illustrated with recent lattice results on the charmonium-like states Zc and X(3872), conventional resonances, bound states and pentaquarks.
454. Nuclear Theory/RIKEN seminar
"Resumming large radiative corrections in the high-energy evolution of the Color Glass Condensate"
Presented by Edmond Iancu, CEA Saclay
Friday, July 24, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Speren Schlichting
The BK-JIMWLK equations describing the evolution of the Color Glass Condensate with increasing energy have recently been extended to next-to-leading order (NLO) accuracy. However, some of the NLO corrections turn out to be extremely large, since amplified by (double and single) collinear' logarithms, i.e. logarithms of ratios of transverse momenta. This difficulty points towards the existence of large radiative corrections to all orders in $\alpha_s$, as generated by the transverse phase-space, which must be computed and resummed in order to restore the convergence of the perturbative expansion. In a couple of recent papers, we developed a resummation scheme in that sense, which achieves a complete resummation of the double-logarithmic corrections and a partial resummation of the single-logarithmic ones (including the running coupling effects). We have thus deduced a collinearly-improved version of the BK equation which includes the largest radiative corrections to all orders. To demonstrate the usefulness of this equation as a tool for phenomenology, for have used it for fits to the HERA data for electron-proton deep inelastic scattering at high energy. We have obtained excellent fits with a reduced number of free parameters and with initial conditions at low energy taken from perturbative QCD.
455. Science on Screen
"Where Physics Meets Fashion: 'Zoolander' With Ãgnes Mócsy"
Thursday, July 23, 2015, 7 pm
Cinema Arts Centre in Huntington, New York
456. High Energy Physics Seminar
"New results from the hydrogen channel in Double Chooz"
Presented by Rachel Carr, Columbia University
Thursday, July 23, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Elizabeth Worcester
Beginning in 2011, the Double Chooz experiment has produced increasingly precise measurements of the neutrino oscillation parameter sin22θ13. These measurements rely on the detection of reactor antineutrinos through the inverse beta decay (IBD) interaction. The most recent analysis uses IBD interactions followed by neutron capture on hydrogen, rather than the standard Gd capture channel. A new artificial neural network-based signal selection, novel background rejection techniques, and reduced detection systematics make this analysis far more sensitive than the original H-channel measurement in Double Chooz. The precision of this new sin22θ13 measurement approaches that of the Gd-channel measurement, demonstrating the possibility of performing high-sensitivity physics measurements without a Gd dopant.
457. Condensed-Matter Physics & Materials Science Seminar
"Discovery of Weyl fermions in condensed matter"
Presented by Hong Ding, Inst. of Physics, Chinese Academy of Sciences, China
Wednesday, July 22, 2015, 1:30 pm
Bldg. 734, ISB Conf. Room 201 (upstairs)
Hosted by: Peter D. Johnson
In 1929, a German mathematician and physicist Hermann Weyl proposed that a massless solution of the Dirac equation represents a pair of new type of particles, the so-called Weyl fermions. However, their existence in particle physics remains elusive after more than eight decades, e.g., neutrino has been regarded as a Weyl fermion in the Standard Model until it was found to have mass. Recently, significant advances in both topological insulators and topological semimetals have provided an alternative way to realize Weyl fermions in condensed matter as an emergent phenomenon. Weyl semimetals are predicted as a class of topological materials that can be regarded as three-dimensional analogs of graphene breaking time reversal or inversion symmetry. Electrons in a Weyl semimetal behave exactly as Weyl fermions, which have many exotic properties, such as chiral anomaly, magnetic monopoles in the crystal momentum space, and open Fermi arcs on the surface. In this talk I will report our discovery of a Weyl semimetal in TaAs by observing Fermi arcs in the surface states and Weyl nodes in the bulk states using angle-resolved photoemission spectroscopy.
""A Holistic Approach to Accelerator Reliability Modeling""
Presented by Miha Rescic, University of Huddersfield
Wednesday, July 22, 2015, 1:30 pm
Bldg 911B, Large Conf. Rm. Rm A202
Hosted by: Steve Peggs/Kevin Brown
"High reliability has become a crucial issue in the design and operation of accelerators due to the demands of specific applications (e.g. medical accelerators, neutron spallation sources, nuclear waste transmutation). This is particularly relevant for accelerator-driven neutron facilities and for Accelerator-Driven Systems technologies for waste transmutation. Until now, accelerator reliability analysis has mostly been performed using simplified methods either in the design phase of projects, or after the accelerator is operational. This talk discusses a holistic approach to accelerator reliability modeling using Hidden Markov Models to look for emergent behavior of the accelerator, using system-complexity agnostics datasets from the operating machine, e.g. beam current or charge."
459. Condensed-Matter Physics & Materials Science Seminar
"Imaging and Understanding Atomic-Scale Surface Interactions: Quantitative Investigations Using In Situ Electron Microscopy"
Presented by Prof. Tevis Jacobs, University of Pittsburgh
Monday, July 20, 2015, 1:30 pm
Conference Room, Building 480
Hosted by: Myung-Geun Han
The atomic-scale mechanisms that govern the adhesion, mechanical deformation, and bonding of surfaces in contact are not well understood. Yet accurate description and prediction of such contact phenomena is critically important in advanced nanoscale applications, including scanning probe microscopy (e.g., nanoscale mapping of mechanical and functional properties), micro-/nano-electromechanical systems (e.g., actuators, switches), and nanomanufacturing processes (e.g., scanning probe lithography). In this talk, I will discuss contact and sliding tests on nanoscale tips of silicon and other technologically relevant materials. These tests were performed inside of a transmission electron microscope (TEM), enabling in situ interrogation of a contact interface while controlling the displacement of the bodies and measuring normal forces with sub-nanonewton resolution. Quantitative data were extracted using custom analysis routines to resolve the geometry of the contacting bodies, adhesive forces, and volumes removed due to sliding wear, all with unprecedented resolution. In the first part of the talk, TEM adhesion tests of carbon-based coatings on diamond performed using this setup will be discussed. Sub-nanonewton force resolution was paired with Angstrom-scale measurements of asperity geometry. Combined with complementary molecular dynamics simulations, these results revealed an order-of-magnitude reduction in apparent work of adhesion as tip roughness increased from atomic-scale corrugation to a root-mean-square value of 1 nm. These results demonstrate the strong effect of sub-nanoscale topography on adhesion, and highlight a key limitation of conventional approaches for measuring the work of adhesion. In the second part of the talk, in situ sliding tests of silicon tips sliding on diamond at low applied loads reveal that wear occurs by atomic attrition: gradual material removal at the atomic scale. The process can be accurately described using stress
460. Nuclear Theory/RIKEN seminar
"The LPM effect in energy loss and sequential bremsstrahlung"
Presented by Peter Arnold, University of Virginia
Friday, July 17, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
High-energy particles passing through matter lose energy by showering via hard bremsstrahlung and pair production. At very high energy, the quantum duration of each splitting process, known as the formation time, exceeds the mean free time for collisions with the medium, leading to a significant reduction in the splitting rate, known as the Landau-Pomeranchuk-Migdal (LPM) effect. A long-standing problem in field theory has been to understand how to implement this effect in cases where the formation times of two consecutive splittings overlap. I will review why this question is interesting and discuss recent progress in the context of jet energy loss in quark-gluon plasmas.
461. Instrumentation Division Seminar
"Design of specific high speed converters at LPSC Grenoble"
Presented by Daniel Dzahini, Laboratory of Subatomic Physics and Cosmology, Grenoble, France
Wednesday, July 15, 2015, 2:30 pm
Large Conference Room, Bldg. 535
This presentation will describe the design of specific high speed and high resolution converters in LPSC Grenoble. ADC designs for calorimeters and different pixels detectors will be discussed in detail. Trends and constraints for future converter designs in DSM process will also be described.
462. Condensed-Matter Physics & Materials Science Seminar
"Revisiting Josephson junction phase dynamics and its codes"
Presented by Francesco Tafuri, Seconda Università di Napoli & CNR-SPIN, Unità di Napoli, Italy
Monday, July 13, 2015, 1:30 pm
Bldg. 480 Conference Room
Hosted by: Ivan Bozovic
The Josephson effect is still a unique key towards a variety of frontier problems ranging from the detection of Majorana fermions to macroscopic quantum phenomena and qubit applications. Progress in material science in producing a larger variety of interfaces and in nanotechnologies applied to superconductivity, may promote a renewal on the paradigms of the phase dynamics of Josephson junctions with relevant consequences on a series of key issues. We will discuss some relevant experiments mostly realized on unconventional junctions, including hybrid devices, nano-junctions, and especially high critical temperature superconductors (HTS). Novel phenomena emerge because of the possibility of driving materials and junctions with an accurate control in unexplored regimes. We have investigated different micro-structural configurations, which offer a wide range of junction dynamical parameters. A transition from classical Josephson phase dynamics, which takes place in junctions characterized by low values of critical current density Jc, to a regime in which dissipation is driven by local heating processes, for high values of Jc. We demonstrate how non-equilibrium effects and local processes in constrained geometry are codified in the response of the junctions and can be disentangled from other effects. Escape dynamics turns as an active 'imaging' of nano-scale transport with an enormous potential and the ability of encoding subtle transport information in fluctuations. We speculate on possible intrinsic nanoscale ordering occurring in HTS systems. This transition is of relevance for all kinds of weak links including the emergent family of nano-hybrid junctions. Information on the search of quantum phase slips can be also derived. Experiments on reference systems as HTS nanowires and Josephson junctions with ferromagnetic spin-valve tunnel barriers (experiment made in collaboration with University of Cambridge) will be finally
""Cascaded Longitudinal Space Charge Amplifier for Short-Wavelength Radiation Generation at Fermilab's ASTA""
Presented by Aliaksei Halavanau, Northern Illinois University
Friday, July 10, 2015, 11 am
Bldg 911B, Large Conf. Rm., Rm. A202
"Longitudinal space charge (LSC) effects are generally considered as detrimental in free-electron lasers as they can seed unwanted energy modulations and emittance growth. There has however been an increasing interest in devising accelerator beam lines capable of sustaining this LSC instability as a mechanism to operate as a coherent light source. In such a cascaded longitudinal space charge amplifier (LSCA), initial noise present in the beam density is amplified via the interplay of longitudinal space charge forces and properly located dispersive sections. To date most of these studies have been carried out with a one-dimensional impedance model for the LSC. We use an available grid-less three-dimensional N-body Barnes-Hut'' algorithm to simulate the 3D space charge force in the beam combined with ELEGANT and explore the limitations of the 1D model often used. We investigate, via numerical simulations, the performances of a cascaded LSCA beam line at the Fermilab's Advanced Superconducting Test Accelerator (ASTA)."
464. RIKEN Lunch Seminar
"Short-distance matrix elements for D-meson mixing for 2+1 flavor lattice QCD"
Presented by Chia Cheng Chang, University of Illinois at Urbana-Champaign
Thursday, July 2, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Tomomi Ishikawa
465. Nuclear Physics Seminar
"In search of old and new anomalous chiral effects in heavy ion collisions"
Presented by Jinfeng Liao, Indiana University
Tuesday, June 30, 2015, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Oleg Eyser
The heavy ion collision provides a unique many-body environment where local domains of strongly interacting chiral medium may occur. Certain anomalous transport processes, forbidden in usual medium, become possible in such domains. These anomalous chiral effects have their microscopic origin at the fundamental quantum anomaly and manifest themselves macroscopically in hydrodynamic currents. In the first part of this talk we report our recent finding (arXiv:1504.03201) of a new gapless collective excitation, called the Chiral Vortical Wave (CVW) in a rotating quark-gluon plasma. The CVW wave equation will be derived, and we show that its solutions describe nontrivial CVW-induced charge transport. We further propose and estimate possible experimental signals. In the second part of this talk we report our state-of-the-art simulations of the long-sought-after Chiral Magnetic Effect (CME), performed in the anomalous hydrodynamic framework and taking into account identified background contributions (arXiV:1504.06906). We discuss the implications of our results for the experimental search of CME
466. Condensed-Matter Physics & Materials Science Seminar
"Microscopic engineering of complex oxide ground states"
Presented by Derek Meyers, University of Arkansas
Monday, June 29, 2015, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: Mark Dean
Transition metal oxides have come to the forefront of condensed matter research in the past several decades due to their highly diverse phase space and remarkable susceptibility to external tuning. This has lead to their prevalence in the pursuit of designer phases, i.e. room temperature superconductivity, topological phases, and etc. In this talk we explore several methods for engineering the ground state of these systems including "ordered doping", applied epitaxial strain, and superlattice heterostructuring in an effort to gain further insight into the microscopic origin of this tunability. We employ synchrotron based x-ray spectroscopy and resonant diffraction to elucidate the explicit origin of the observed anomalous behaviors. In particular, our results reveal the ability to mask the effects of spin-orbit coupling in heavier oxides and to suppress or enhance bulk phase transitions by design.
467. Nuclear Theory/RIKEN Seminar
"Event by Event fluctuations in pQCD + saturation + hydro model: pinning down QCD matter shear viscosity in AA collisions"
Presented by Risto Paatelainen, University of Jyvaskyla
Friday, June 26, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
We introduce an event-by-event perturbative-QCD + saturation + hydro ("EKRT") framework for ultrarelativistic heavy-ion collisions, where we compute the produced fluctuating QCD-matter energy densities from next-to-leading order perturbative QCD using a saturation conjecture to control soft particle production, and describe the space-time evolution of the QCD matter with dissipative fluid dynamics, event by event. We perform a simultaneous comparison of the centrality dependence of hadronic multiplicities, transverse momentum spectra, and flow coefficients of the azimuth-angle asymmetries, against the LHC and RHIC measurements. We compare also the computed event-by-event probability distributions of relative fluctuations of elliptic flow, and event-plane angle correlations, with the experimental data from Pb+Pb collisions at the LHC. We show how such a systematic multi-energy and multi-observable analysis tests the initial state calculation and the applicability region of hydrodynamics, and in particular how it constrains the temperature dependence of the shear viscosity-to-entropy ratio of QCD matter in its different phases in a remarkably consistent manner.
468. RIKEN Lunch Seminar
"One-Flavor QCD and the Dirac Spectrum at $\theta=0$"
Presented by Jacobus Verbaarschot, Stony Brook University
Thursday, June 25, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Daniel Pitonyak
The chiral condensate of one-flavor QCD is continuous when the quark mass crosses zero. In the sector of fixed topological charge though, the chiral condensate becomes discontinuous at zero mass in the the thermodynamical limit. To reconcile these contradictory observations, we have evaluated the spectral density of the Dirac operator in the epsilon domain of one-flavor QCD. In this domain, we have obtained exact analytical expressions which show that the spectral density at $\theta = 0$ becomes a strongly oscillating function for negative quark mass with an amplitude that increases exponentially with the volume. As is the case for QCD at nonzero chemical potential, these strong oscillations invalidate the Banks-Casher formula and result in a chiral condensate that is continuous as a function of the quark mass. An additional subtlety is the effect of the topological zero modes which will be discussed as well.
469. Nuclear Theory/RIKEN seminar
"Jet angular broadening in Heavy-Ion collisions"
Presented by Yacine Mehtar-Tani, University of Washington
Friday, June 19, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
The advent of the LHC opened up new perspectives for jet-quenching physics. For the first time, high enough energies are reached in heavy-ion experiments to produced jets in large numbers, and the unprecedented detector capabilities of ALICE, ATLAS and CMS, not only extend the kinematic range for the measurements previously performed at RHIC, but also allow to explore a variety of new jet-quenching observables. In this talk, I address the question of the angular broadening of jets in the presence of a dense QCD matter. I start by discussing the fundamental mechanisms underlying the formation of gluon cascades induced by multiple interactions of high energy jets with the quark-gluon plasma. Then, the rate equation that describes the evolution of the energy and angular distribution of the in-medium gluon shower is presented and solved. Two remarkable phenomena emerge. First and foremost the energy spectrum (of jet constituents) exhibits a scaling behavior characterized by a constant flow of energy towards low momenta akin to wave turbulence. As a result, energy is rapidly transported from the energy containing partons to low momentum gluons before it dissipates into the medium. Second, medium-induced gluon cascades develop and transport energy at parametrically large angles with respect to the jet axis. This picture is in semi-quantitive agreement with a recent CMS analysis of the missing energy in asymmetric dijet events where the energy balance is recovered at large angles and very soft particles.
470. PubSci
"Big Bang Physics and the Building Blocks of Matter"
Thursday, June 18, 2015, 7 pm
The Bahche 191 7th St, Brooklyn, NY 11215
Invite your friends and colleagues to a lively discussion for the science-interested (or just plain curious) and chat with scientists in an informal and friendly way. No stuffy lectures â€" just a dynamic talk with a diverse audience and a lot of good cheer. Physicists who work at Brookhaven's particle collider will talk about how they explore what happened at the dawn of time from a Lab on Long Island. How did the Universe take shape? What binds matter together? How do we answer those questions?
471. Particle Physics Seminar
"Detection of Lensing of the CMB by Dark Matter Halos"
Presented by Mathew S Madhavacheril, Stony Brook University
Thursday, June 18, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Morgan May
I will report on the first detection of lensing of the cosmic microwave background by dark matter halos. Halo lensing of the CMB provides a method for constraining cluster masses complementary to optical weak lensing, with the advantage that the source plane has a very well determined redshift and statistical properties. In this work, the lensing field was reconstructed from CMB temperature observations using the ACTPol telescope and stacked at the location of CMASS galaxies which trace dark matter halos of ~10^13 M_solar galaxy groups, providing a 3.2 sigma detection and a ~35% mass constraint. I will also briefly touch on the capabilities of future CMB experiments to use this method to constrain dark energy parameters.
472. RIKEN Lunch Seminar
"Self-similar evolution for inverse cascade of magnetic helicity driven by the chiral anomaly"
Presented by Yi Yin, Brookhaven National Laboratory
Thursday, June 18, 2015, 12:30 pm
Small Seminar Room, Bldg. 510
Hosted by: Daniel Pitonyak
We show by solving Maxwell's equations in the presence of chiral magnetic current that the chiral anomaly would induce the inverse cascade of magnetic helicity. We found at late time, the evolution of magnetic helicity spectrum is self-similar and axial charge decays as a power law in time. We visualize how a linked magnetic configuration would evolve into a knotted configuration in real space during such evolution.
473. HET/RIKEN Lunch Seminar
"Light Inflaton â€" hunting for it from CMB through the Dark Matter and down to the colliders"
Presented by Fedor Bezrukov, RBRC/U Conn
Friday, June 12, 2015, 12 pm
Building 510 Room 2-95
Hosted by: Amarjit Soni
474. Particle Physics Seminar
"Constraining the Standard Model and new physics with LHC data"
Presented by Alessandro Tricoli, CERN
Friday, June 12, 2015, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Ketevi Assamagan
The Large Hadron Collider (LHC) project at CERN Laboratory in Geneva has achieved one of its primary goals, i.e. the discovery of the Higgs boson particle, which completes the Standard Model of particle physics. However, no signatures of new physics beyond the Standard Model have been observed yet, despite thorough searches. Nature turns out to be subtle. The direct search will continue in the upcoming LHC runs, however new physics can also be pursued indirectly by looking for deviations of experimental results from predictions in measurements of Standard Model processes. The LHC has provided a large data set during its first years of operations. This has been used to perform measurements of Standard Model processes that constrain predictions in the strong and electro-weak sectors and are sensitive to new physics in a model-independent way, thanks to the high level of precision and the extent of their kinematic reach. A good understanding of these processes is of paramount importance for precision Higgs physics, as well as for searches for new physics, as they constitute irreducible backgrounds. After presenting a selection of highlights of recent Standard Model measurements from the LHC, I will discuss how the precision and phase space reach of these measurements will improve in future LHC runs, given the increase of centre-of-mass energy and integrated luminosity, emphasising some of the experimental challenges ahead.
475. Particle Physics Seminar
"Search for dark sector particles at Belle and Belle II"
Presented by Igal Jaegle, University of Hawaii at MÄnoa
Thursday, June 11, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Ketevi A. Assamagan
The dark photon, A′,, and the dark Higgs boson, h′, are hypothetical constituents featured in a number of recently proposed Dark Sector Models. We will present a search for these particles in the so-called Higgs-strahlung channel, e+eâˆ'â†'A′h′, with h′â†'A′A′. We investigated ten exclusive final-states with A′â†'e+eâˆ', μ+μâˆ', or Ï€+Ï€âˆ', in the mass ranges 0.1 GeV/c2 <mA′<3.5 GeV/c2 and 0.2 GeV/c2 <mh′<10.5 GeV/c2. We also investigated three inclusive final-states, 2(e+eâˆ')X, 2(μ+μâˆ')X, and (e+eâˆ')(μ+μâˆ')X, where X denotes a dark photon candidate detected via missing mass, in the mass ranges 1.1 GeV/c2 <mA′<3.5 GeV/c2 and 2.2 GeV/c2 <mh′<10.5 GeV/c2. Using the entire 977fbâˆ'1 data set collected by Belle, we observed no significant signal. We will also discuss prospects for searches for light dark matter and the dark photon in the radiative decay process at Belle and Belle II.
476. HET/RIKEN seminar
"New physics in b—>s transitions after LHC run 1"
Presented by Wolfgang Altmannshofer, Perimeter Institute
Wednesday, June 10, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Chien-Yi Chen
I will discuss interpretations of the recent updated angular analysis of the B->K*mu+mu- decay by the LHCb collaboration. A global fit to all relevant measurements probing the flavor changing neutral current b->s mu mu transition shows tensions with Standard Model expectations. Assuming hadronic uncertainties are estimated in a sufficiently conservative way, I will discuss the implications of the experimental results on new physics, both model independently as well as in the context of models with flavor changing Z' bosons.
477. Nuclear Theory/RIKEN seminar
"Novel mechanisms of charmonium suppression/enhancement in pA and AA collisions"
Presented by Boris Kopeliovich, Universidad Tecnica Federico Santa Maria, Valparaiso
Friday, June 5, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Charmonium production in pA collisions is known to be suppressed by shadowing and absorption. There are however nuclear effects, which enhance charmonium yield. They steeply rise with energy and seem to show up in LHC data for J/psi production in pA collisions. In the case of heavy ion collisions produced charmonia are additionally suppressed by final state interaction in the created dense medium. On the contrary to current evaluations of the melting effects caused by Debye screening, a charmonium produced with a large pT easily survives even at high temperatures. Another source of charmonium suppression, missed in previous calculations, color-exchange interactions with the medium, leads to suppression of a comparable magnitude. A quantitative comparison is performed.
478. Condensed-Matter Physics & Materials Science Seminar
"GGE and applications for integrable models"
Presented by Garry Goldstein, Rutgers University
Thursday, June 4, 2015, 4 pm
ISB 2nd floor seminar room
Hosted by: Robert Konik
We consider quenches of integrable models. We derive a Yudson representation applicable to finite sized systems. Using this representation we find expressions for the time dependence of density density and related correlation functions for an arbitrary quench of the repulsive LiebLiniger gas. We use this to show that the GGE formalism is applicable to the long time limit for quenches of the Lieb-Liniger gas with sufficiently regular initial states. We then show that no similar GGE formalism applies to quenches for integrable models with bound states (such as the XXZ model or the Hubbard model). We study several specific examples of quenches, in particular quenches where the initial state is a Mott insulator or has low entropy. We find the exact quasiparticle density for such quenches and use it to study the long time limit of some correlation functions for the system. We also consider quenches of confined systems, in particular the Lieb-linger gas in a box. We show that the GGE formalism applies to the long time average of such quenches. We use this observation to compute the long time average quasiparticle density for some quenches similar to the Quantum Newton's cradle quench experiment. We also compute various correlation functions for the system in particular the probability distribution for the particle velocity.
479. Condensed-Matter Physics & Materials Science Seminar
"Band edge and photo induced superconductivity"
Presented by Garry Goldstein, Rutgers
Thursday, June 4, 2015, 1:30 pm
2nd Fl Lecture Room ISB
Hosted by: Robert Konik
We discuss novel routes to obtain superconductivity in semiconductors. We consider a semiconductor with a band dispersion where there is a band edge, such as semiconductors with Rashba spin-orbit coupling or bilayer graphene with a voltage between the layers. We find robust superconductivity, both p-wave and s-wave depending on the type of band edge, for semiconductors with attractive interactions (such as those caused by phonon exchange) when we tune the chemical potential close to the band edge. We also consider photo induced superconductivity in a two band semiconductor. We use optical pumping to induce nonequilibrium populations within the bands. We find robust superconductivity for appropriate chemical potential and dispersion relations for the bands. This s-wave superconductivity can be induced by both repulsive and attractive interactions depending on the exact band dispersions. Various band geometries are discussed.
480. RIKEN Lunch Seminar
"Non-relativistic particles in a thermal bath"
Presented by Antonio Vairo, Munich Technical University
Thursday, June 4, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Tomomi Ishikawa
481. HET/RIKEN Seminar
"Cascade Decays of a Leptophobic Boson"
Presented by Bogdan Dobrescu, Fermilab
Wednesday, June 3, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Chien-Yi Chen
482. Physics Colloquium
"Quarkonium with Effective field theories"
Presented by Nora Brambilla, Munich Technical University
Tuesday, June 2, 2015, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Peter Petreczky
Quantum Chromodynamics (QCD) is the sector of the Standard Model of particle physics that describes the strong interaction, deceptively simple to formulate but notoriously difficult to solve. Heavy quarkonium is a multiscale system that probes the different energy regimes of QCD, from the high-energy region, where an expansion in the coupling constant is possible and precision studies may be done, to the low-energy region, dominated by confinement and the many manifestations of the nonperturbative strong dynamics. Properties of production and absorption of quarkonium in a medium are also crucial for the study of QCD at high density and temperature. On the theoretical side, the construction of new nonrelativistic effective field theories for quarkonium has recently revolutionized the field providing both a conceptual framework and a powerful calculational tool. On the experimental side, the diversity, quantity and accuracy of the data collected in the last few years at B and tau-charm factories and at RHIC and LHC experiments is impressive, featuring the observation of new states and new unexpected processes. I will discuss these theoretical and experimental advancements and their implications for our understanding of strong interactions.
483. Nuclear Physics Seminar
"Elliptic flow from anisotropic escape"
Presented by Denes Molnar, Purdue University
Tuesday, June 2, 2015, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Jin Huang
While hydrodynamics is regarded as the dominant paradigm for describing heavy-ion collisions at RHIC and LHC energies, its applicability to nuclear reactions is not very well understood. Open question remain about the mechanism of rapid thermalization, initial conditions, treatment of decoupling (conversion of the fluid to particles), finite system effects, and quantum corrections in very small systems, for example. In a recent work (arXiv:1502.05572) we showed that in the AMPT transport model elliptic flow is generated quite differently from hydrodynamics, mainly through anisotropic escape from the collision zone. I will demonstrate that this is, in fact, a general feature of kinetic theory, originating in the modest opacities <Ncoll> \sim 4-5 in AMPT calculations. Implications of the escape effect will be discussed together with connections to other hydro related problems such as proper particle distributions (arXiv:1404.8750) and anisotropic flow from quantum mechanics (arXiv:1404.4119).
484. Particle Physics Seminar
"LHCb Run I Results and Run II Prospects"
Presented by Philip Ilten, Massachusetts Institute of Technology
Thursday, May 28, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Ketevi A. Assamagan
The LHCb detector is a forward arm spectrometer on the Large Hadron Collider, designed for the study of particles containing b or c quarks. A variety of recent results from the Run I dataset, taken from 2010 - 2013, will be presented, emphasizing the scope of the LHCb physics program. These areas include central exlusive production of quarkonia, exotic particle searches, precision electroweak cross-sections, CKM measurements, and more. Prospects for Run II measurements will be outlined.
485. Condensed-Matter Physics & Materials Science Seminar
"Transport properties of novel thermoelectric materials"
Presented by Hang Chi, Department of Physics, University of Michigan
Thursday, May 28, 2015, 11 am
Bldg.480 Conf. Rm
Hosted by: Qiang Li
Thermoelectric materials can recover waste industrial heat and convert it to electricity as well as provide efficient local cooling of electronic devices. The efficiency (determined by the dimensionless figure-of-merit ZT) of such environmentally responsible and exceptionally reliable solid state energy conversion can be enhanced through (i) electronic band engineering (n-type Mg2Si-Mg2Sn solid solutions and p-type SnTe) and (ii) thermal conductivity reduction (Ge/Te double substituted CoSb3). Detailed transport and structure studies of Bi2Te3-based single crystals demonstrate that a bulk (semi-)insulating state for such a topological insulator can be achieved via group III (Tl or In) elemental doping, which opens an avenue for further investigations of transport phenomena related to surface states. Further systematic study in Bi2Te3-based molecular beam epitaxial (MBE) thin films grown on sapphire (0001) and/or BaF2 (111) substrates, reveal that the peak of phonon drag can be tuned by the choice of substrates with different Debye temperatures.
486. Brookhaven Lecture
"505th Brookhaven Lecture: 'Scanning the Structure of Steel From Nuclear Reactor Vessels'"
Presented by Lynne Ecker, Nuclear Science & Technology Department
Wednesday, May 27, 2015, 4 pm
Berkner Hall Auditorium
Hosted by: Thomas Watson
487. Nuclear Physics Seminar
"Probing Nucleon Structure Through Transversely Polarized Proton-proton Collisions at STAR"
Presented by Jim L. Drachenberg, Valparaiso University
Tuesday, May 26, 2015, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Oleg Eyser
At leading twist, a complete picture of the one-dimensional momentum structure of the nucleon requires knowledge of three types of parton distribution functions (PDFs): the unpolarized PDFs; the helicity PDFs; and the transversity PDF, related to the transverse polarization of quarks within a transversely polarized nucleon. Current global extractions of transversity are limited by the kinematic reach of existing semi-inclusive deep-inelastic scattering (SIDIS) experiments. Beyond the open questions of one-dimensional nucleon structure, myriad opportunities abound in exploring the multi-dimensional structure of the nucleon. A step toward this goal is to investigate the nature of the transverse momentum dependence (TMD) of nucleon parton densities and their relation to nucleon spin polarization. The STAR experiment at RHIC proposes to investigate these and other spin-related phenomena through the interaction of high-energy collisions between spin-polarized protons. In preliminary results from data collected in 2011 at $\sqrt{s}=500$ GeV and in 2012 at $\sqrt{s}=200$ GeV, STAR has observed the first non-zero spin asymmetries due to the effects of transversity in proton-proton collisions. Studying these effects through both jet+hadron and di-hadron production channels and across a range of collision energy yields the potential not only to extend understanding of transversity beyond the current kinematic reach but also to address longstanding theoretical questions concerning the universality and evolution of transversity and polarized fragmentation functions. From the 2011 dataset STAR has also released the first preliminary measurements sensitive to the Sivers TMD PDF in weak-boson production. Weak boson production provides an ideal tool for isolating the unconstrained sea-quark Sivers PDF and may provide sensitivity to the expected modified universality of the Sivers PDF when compared to SIDIS. These exploratory measurements pave the way for future higher precision inv
488. RIKEN Lunch Seminar
"Dysonian dynamics of the Ginibre ensemble"
Presented by Piotr Warchol, Jagiellonian University
Thursday, May 21, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Tomomi Ishikawa
I will present a study of the time evolution of Ginibre matrices whose elements undergo Brownian motion. The non-Hermitian character of the Ginibre ensemble binds the dynamics of eigenvalues to the evolution of eigenvectors in a non-trivial way, leading to a system of coupled nonlinear equations resembling those for turbulent systems. We will formulate a mathematical framework allowing simultaneous description of the flow of eigenvalues and eigenvectors, and unravel a hidden dynamics as a function of new complex variable, which in the standard description is treated as a regulator only. We shall solve the evolution equations for large matrices and demonstrate that the non-analytic behavior of the Green's functions is associated with a shock wave stemming from a Burgers-like equation describing correlations of eigenvectors. I will start by reviewing similar notions in a simpler, Hermitian setting. Joint work with Zdzislaw Burda, Jacek Grela, Maciej A. Nowak and Wojtek Tarnowski (Phys.Rev.Lett. 113 (2014) 104102).
489. Nuclear Physics Seminar
"Low pT photon production at confinement: The missing piece to the direct photon puzzle"
Presented by Dr. Sarah Campbell, Columbia University
Tuesday, May 19, 2015, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Jin Huang
Low pT direct photons in Au+Au collisions are produced in excess of the TAA-scaled p+p yields and with a large azimuthal anisotropy, v2. This talk considers that these low pT direct photons are produced by radially boosted quarks undergoing soft-gluon mediated quark-anti-quark interactions as the system becomes color-neutral. A Monte Carlo simulation of direct photons and Chi-squared comparisons of the published PHENIX direct photon and identified particle v2 data are used to test this description. The Monte Carlo simulation reproduces the shape of the direct photon pT excess and the resulting direct photon v2 agrees, despite being systematically low, with the published 0-20% and 20-40% Au+Au low pT direct photon v2 in both centralities. Comparisons to recent preliminary direct photon results will also be shown.
490. Nuclear Theory/RIKEN seminar
"Off-shell amplitudes and their applications"
Presented by Piotr Kotko, Pennsylvania State University
Friday, May 15, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
"A Robinson Wiggler for Lifetime and Brilliant Improvement at the Metrology Light Source"
Presented by Tobias Goetsch, Helmholtz-Zentrum, Germany
Thursday, May 14, 2015, 4 pm
Large Conf. Rm. Bldg. 911B, Rm. A202
Hosted by: Wolfram Fischer
"The beam lifetime in electron storage rings concerns machines running in decay mode as well as machines doing top-up. A standard procedure to increase the lifetime is via bunch lengthening as the lifetime depends on the electron density in the bunch. Bunch lengthening is typically achieved with higher harmonic (Landau) cavities. There are several advantages in using a different approach: it is possible to increase the bunch length by installing a transverse gradient (Robinson) Wiggler, which allows to transfer damping between the horizontal and the longitudinal plane. While increasing the bunch length, the horizontal emittance is being reduced yielding advantages regarding the source size depending on the magnet optics. At the Metrology Light Source, a primary source standard used by Germanys national metrology institute (Physikalisch-Technische Bundesanstalt), such a scheme is being investigated. The prospects are higher brilliance for the important beamlines together with a lifetime improvement in the order of 100 %."
492. Particle Physics Seminar
"Dark matter search results from the PandaX-I experiment"
Presented by Mengjiao Xiao, Shanghai Jiao Tong University
Thursday, May 14, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Elizabeth Worcester
The dark matter is a leading candidate to explain gravitational effects observed in galactic rotational curves, galaxy clusters, and the large scale structure formation, etc. The nature of dark matter is one of the most fundamental problems in physics. Proposals of dark matter candidates usually involve new physics and new particles. Among the various candidates, one compelling class of particles are WIMPs (Weakly Interacting Massive Particles). WIMPs are being studied in colliders, indirect and direct detection experiments. In recent years, new techniques in WIMP direct detection using noble liquids (xenon, argon) have shown exceptional potential due to the capability of background suppression and discrimination, and scalability to large target masses. PandaX is a low threshold dual-phase xenon dark matter experiment operating at the China Jin-Ping Underground Laboratory (CJPL). The PandaX detector is staged. We released the first dark matter search data for PandaX-I on August 2014. In this talk, I will give an introduction to the PandaX-I detector, and then followed by the details of the physics analysis as well as the latest results.
493. RIKEN Lunch Seminar
"Geometrical scaling - a window to saturation"
Presented by Michal Praszalowicz, Jagiellonian University
Thursday, May 14, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Daniel Pitonyak
Geometrical is a consequence of a traveling wave solution of the non-linear QCD evolution equation, so called Balitski-Kovchegov equation. We shall demonstrate the existence of GS in various high energy reactions. Among different consequences of GS there is a linear rise of charged particle multiplicity (Nch) and mean transverse momentum (pT) with scattering energy. Furthermore, a correlation of meant pT and Nch is predicted to scale in a way that depends on the the way particles are produced from the volume excited in a hadron-hadron scattering. This is mostly visible in heavy ion collisions at different centralities.
494. HET/RIKEN seminar
"Colorless Top Partners and Naturalness"
Presented by Gustavo Burdman, IAS/University of São Paulo
Wednesday, May 13, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: CheinYi Chen
495. Physics Colloquium
"Where Did Half the Starlight in the Universe Go"
Presented by Mark Devlin, University of Pennsylvania
Tuesday, May 12, 2015, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Peter Yamin
We believe that approximately half of all the light from stars is absorbed and reprocessed by dust. The resulting emission is grey body with a temperature near 30 Kelvin. The COBE satellite made the first measurements of the resulting Far Infrared Background (FIRB), but since that time, we have been unable to resolve the background into individual galaxies. The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) was designed to do this job. Its three bands at 250, 350, and 500 microns span the peak in emission for galaxies at z=1. I will discuss the BLAST experiment and present results from our measurements of resolved and unresolved galaxies. I will also discuss the implications for star formation in our own galaxy and how dust is changing the way we look at current and future searches for primordial gravity waves with the Cosmic Microwave Background.
496. Nuclear Theory/RIKEN Seminar
"Solving the NLO BK equation in coordinate space"
Presented by Tuomas Lappi, University of Jyvaskyla
Friday, May 8, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
We present results from a numerical solution of the next-to-leading order (NLO) Balitsky-Kovchegov (BK) equation in coordinate space in the large Nc limit. We show that the solution is not stable for initial conditions that are close to those used in phenomenological applications of the leading order equation. We identify the problematic terms in the NLO kernel as being related to large logarithms of a small parent dipole size, and also show that rewriting the equation in terms of the "conformal dipole" does not remove the problem. Our results qualitatively agree with expectations based on the behavior of the linear BFKL equation.
497. HET / Riken Lunch Seminar
"Stealth Composite Dark Matter"
Friday, May 8, 2015, 12 pm
Building 510 Room 2-95
Hosted by: Amarjit Soni
498. RIKEN Lunch Talk
"NLO transverse momentum broadening and QCD evolution of qhat"
Presented by Hongxi Xing, Los Alamos National Lab
Thursday, May 7, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Daniel Pitonyak
499. Nuclear Theory/RIKEN Seminar
"Applications of Soft-Collinear Effective theory to hadronic and nuclear collisions"
Presented by Ivan Vitev, Los Alamos National Laboratory
Friday, May 1, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Effective field theory (EFT) is a powerful framework based on exploiting symmetries and controlled expansions for problems with a natural separation of energy or distance scales. EFTs are particularly important in QCD and nuclear physics. An effective theory of QCD, ideally suited to jet applications, is Soft-Collinear Effective Theory (SCET). Recently, first steps were taken to extend SCET and describe jet evolution in strongly-interacting matter. In this talk I will demonstrate that the newly constructed theory, called SCETG, allows us to go beyond the traditional energy loss approximation in heavy ion collisions and unify the treatment of vacuum and medium-induced parton showers. It provides quantitative control over the uncertainties associated with the implementation of the in-medim modification of hadron production cross sections and allows us to accurately constrain the coupling between the jet and the medium. I will further show how SCET and SCETG can be implemented to evaluate reconstructed jet observables, such as jet shapes.
500. HET/RIKEN seminar
"Higgs as a Lamp Post of New Physics"
Presented by JiJi Fan, Syracuse
Wednesday, April 29, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Chien-Yi Chen
501. Nuclear Theory/RIKEN seminar
Presented by Laura Tolos, Instituto de Ciencias del Espacio (IEEC-CSIC)
Friday, April 24, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Hadrons under extreme conditions of density and temperature have captured the interest of particle and nuclear physicists as well as astrophysicists over the years in connection with an extensive variety of physical phenomena in the laboratory as well as in the interior of stellar objects, such as neutron stars. One of the physics goals is to understand the origin of hadron masses in the context of the spontaneous breaking of the chiral symmetry of Quantum Chromodynamics (QCD) at low energies in the non-perturbative regime and to analyze the change of the hadron masses due to partial restoration of this symmetry under extreme conditions. Lately other proper QCD symmetries have also become a matter of high interest, such as heavy-quark flavor and spin symmetries. These symmetries appear when the quark masses become larger than the typical confinement scale and they are crucial for characterizing hadrons with heavy degrees of freedom. In this talk I will address the properties of heavy hadrons under extreme conditions based on effective theories that incorporate the most appropriate scales and symmetries of QCD in each case. With the on-going and upcoming research facilities, the aim is to move from the light-quark to the heavy-quark sector and to face new challenges where heavy hadrons and new QCD symmetries will play a dominant role.
502. Biological, Environmental, & Climate Sciences (BECS) Department Seminar
"High-resolution CAM5 simulations of varying complexity"
Presented by Kevin Reed, Stony Brook University
Friday, April 24, 2015, 10 am
Conference Room, Bldg 815E
Hosted by: Ernie Lewis
In our continued effort to understand the climate system and improve its representation in general circulation models (GCMs) it is crucial to develop new methods to evaluate these models. This is certainly true as the GCM community advances towards high horizontal resolutions (i.e., grid spacing less than 50 km), which will require interpreting and improving the performance of many model components. Idealized, or reduced complexity, frameworks can be used to investigate how model assumptions impact behavior across scales. This work makes use of a range of National Center for Atmospheric Research and Department of Energy Community Atmosphere Model version 5 (CAM5) simulations, ranging from simplified global radiative-convective equilibrium (RCE) simulations to full decadal simulations of present-day and future climate. The various CAM5 configurations provide useful insights into the model's ability to simulate extreme precipitation events and tropical cyclones. Furthermore, the impact of horizontal resolution and the choice of CAM5 dynamical core on the simulation of extreme events will be explored. Finally, time slice experiments using the Representative Concentration Pathway (RCP) 8.5 scenario for greenhouse gas concentrations are assessed and compared to present-day simulations. Overall, this work is part of a continued effort to understand how weather extremes may vary in a changing climate using next-generation high-resolution climate models.
503. Particle Physics Seminar
"(Real) Early Universe Cosmology with Quark Gluon Plasma"
Presented by Niayesh Afshordi, Perimeter Institute for Theoretical Physics
Thursday, April 23, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Morgan May
An intriguing possibility that can address pathologies in both early universe cosmology (i.e. the horizon problem) and quantum gravity (i.e. non-renormalizability), is that particles at very high energies and/or temperatures could propagate arbitrarily fast. In this talk, I introduce Thermal Tachyacoustic Cosmology (TTC), i.e. this scenario with thermal initial conditions. We find that a phase transition in the early universe, around the scale of Grand Unified Theories (GUT scale; T∼10^{15} GeV), during which the speed of sound drops by several orders of magnitude within a Hubble time, can fit current CMB observations. However, I will then argue that cosmological bounds on the density of primordial black holes suggest that Lorentz invariance in the primordial thermal plasma may not recover until much lower temperatures, close to the QCD phase transition. This presents the exciting possibility of testing this scenario in the thermal plasma produced in relativistic heavy ion collisions.
504. Particle Physics Seminar
"Implications of Cosmological Observations for History of Early Universe"
Presented by Ghazal Geshnizjani, University of Waterloo/ Perimeter Institute for Theoretical Physics
Wednesday, April 22, 2015, 3 pm
Building 510 Room 2-160
Hosted by: Morgan May
I will argue that any theory of early universe that matches cosmological observations should include a phase of accelerated expansion (i.e. inflation) or it has to break at least one of the following tenets of classical general relativity: Null Energy Conditions (NEC), sub-luminal signal propagation, or sub-Planckian energy densities. This proof extends to a large class of theories with higher (spatial) derivative or non-local terms in the action as well. Interestingly, only theories in the neighbourhood of Lifshitz points with ω ∠k^0 and k^3 are excluded from the proof. I will also discuss in what sense detecting primordial gravitational waves is a smoking gun for inflation.
505. Condensed-Matter Physics & Materials Science Seminar
"Establishing an Atomistic Picture of Gas Adsorption in Metal Organic Frameworks"
Presented by Anna Plonka, SUNY-Stony Brook, Poland
Wednesday, April 22, 2015, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: Simon Billinge/Emil Bozin
506. Physics Colloquium
"Neutrinos and friends in the past and present universe"
Presented by Alex Kusenko, UCLA
Tuesday, April 21, 2015, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Morgan May
Neutrinos play a role in various aspects of cosmology, including production of light elements, and the rate of expansion of the universe. Furthermore, the neutrino masses imply the likely existence of right-handed neutrinos, which can exist in the form of dark matter, and which can explain the matterantimatter asymmetry of the universe. I will discuss the many faces ordinary and hypothetical neutrinos in cosmology.
507. Center for Data-Driven Discovery C3D
"Computing Intensive Problems in Cosmology"
Presented by Anze Slosar
Tuesday, April 21, 2015, 2 pm
John Dunn Seminar Room, Bldg. 463
Hosted by: Robert Harrison
Cosmology is a branch of physics that studies the whole universe as a single physical system. Computing intensive methods are used throughout, both for data analysis and for theoretical modeling. The computational difficulties are in most cases due to existence of gravitational force which is important at all scales. This makes problems fundamentally different from problems in particle physics where each collision event can be considered to be statistically independent. In simulations, it is necessary to take into account the force contribution of any particle to any other and in data analysis the correlations between any two measurements. I will overview problems, solutions and current limitations. Time permitting, I will describe more technical aspects of the code we are developing to analyze data from the spectroscopic datasets.
508. Condensed-Matter Physics & Materials Science Seminar
"Competing Superexchange Interactions in Double Perovskite Osmates"
Presented by Ryan Morrow, Ohio State University
Monday, April 20, 2015, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: Simon Billinge/Emil Bozin
Double perovskites, A2BB'O6, containing mixed transition metal ions have exhibited numerous desirable properties such as colossal magnetoresistance, half metallic transport, and high temperature ferrimagnetism. However, a predictive understanding of the superexchange mechanisms which control the magnetism of these materials when they are insulating and B is 3d transition metal and B' is a 4d or 5d transition metal has remained elusive. In this work, a number of insulating double perovskite osmates, A2BOsO6 (A=Sr,Ca,La; B=Cr,Fe,Co,Ni) have been chosen and studied using magnetometry, specific heat, XMCD, and neutron powder diffraction techniques in order to systematically probe the effects of electronic configuration and bonding geometry on the magnetic ground state. It is concluded that the magnetic properties of these materials are controlled by a competition between short range B��'O��'Os and long range superexchange interactions which are sensitive to bonding geometry resulting in tunability of the magnetic ground state.
509. Nuclear Physics & RIKEN Theory Seminar
"Consistency of Perfect Fluidity and Jet Quenching in semi-Quark-Gluon Monopole Plasmas"
Presented by Jiechen Xu, Columbia University
Friday, April 17, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Abstract: We utilize a new framework, CUJET3.0, to deduce the energy and temperature dependence of jet transport parameter, q^(E>10GeV,T), from a combined analysis of available data on nuclear modification factor and azimuthal asymmetries from RHIC/BNL and LHC/CERN on high energy nuclear collisions. Extending a previous perturbative-QCD based jet energy loss model (known as CUJET2.0) with (2+1)D viscous hydrodynamic bulk evolution, this new framework includes three novel features of nonperturbative physics origin: (1) the Polyakov loop suppression of color-electric scattering (aka "semi-QGP" of Pisarski et al) and (2) the enhancement of jet scattering due to emergent magnetic monopoles near Tc (aka "magnetic scenario" of Liao and Shuryak) and (3) thermodynamic properties constrained by lattice QCD data. CUJET3.0 reduces to v2.0 at high temperatures T>400 MeV, but greatly enhances q^ near the QCD deconfinement transition temperature range. This enhancement accounts well for the observed elliptic harmonics of jets with pT>10 GeV. Extrapolating our data-constrained q^ down to thermal energy scales, E∼2 GeV, we find for the first time a remarkable consistency between high energy jet quenching and bulk perfect fluidity with η/s∼T3/q^∼0.1 near Tc.
510. Particle Physics Seminar
"Cosmology with Strong Gravitational Lenses"
Presented by Phil Marshall, SLAC National Accelerator Laboratory
Thursday, April 16, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Anze Slosar
Strong gravitational lenses have become an important astronomical tool: they allow us to make accurate measurements of galaxy masses, they provide a magnified view of the distant universe, and they allow us to constrain cosmological parameters. In particular, the time delays in multiply-imaged quasar systems enable measurements of distance in the Universe each with around 5% precision. I will present our recent measurement of time delay distance in two galaxy-scale lens systems. For us to realize the potential of this cosmological probe, we need to increase the size of our lens sample, and continue to improve the accuracy of its analysis. I will discuss the potential of LSST to provide a sample of several hundred lensed quasars with well-measured time delays that would enable competitive and complementary constraints on Dark Energy, and describe our ongoing investigations of how to find lenses, infer their time delays and model their mass distributions accurately, and account for weak lensing effects from external mass structures.
511. RIKEN Lunch Seminar
"Jarzynski-type equalities in gambling: role of information in capital growth"
Presented by Yuji Hirono, Stony Brook
Thursday, April 16, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Tomomi Ishikawa
512. High-Energy Physics & RIKEN Theory Seminar
"CKM physics with lattice QCD"
Presented by Aida El-Khadra, University of Illinois at Urbana-Champaign
Wednesday, April 15, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Chris Kelly
513. Nuclear Theory/RIKEN seminar
"Hydrodynamics Beyond the Gradient Expansion: Resurgence and Resummation"
Presented by Michael Heller, Perimeter Institute
Friday, April 10, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
Consistent formulations of relativistic viscous hydrodynamics involve short lived modes, leading to asymptotic rather than convergent gradient expansions. In this talk I will consider the Mueller-Israel-Stewart theory applied to a longitudinally expanding quark-gluon plasma system and identify hydrodynamics as a universal attractor without invoking the gradient expansion. I will give strong evidence for the existence of this attractor and then show that it can be recovered from the divergent gradient expansion by Borel summation. This requires careful accounting for the short-lived modes which leads to an intricate mathematical structure known from the theory of resurgence.
514. HET/RIKEN seminar
Presented by Tongyan Lin, University of Chicago
Wednesday, April 8, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Chien-Yi Chen
515. Physics Colloquium
"The Proton and the Future of Particle Physics"
Presented by Richard Hill, Univ. Chicago
Tuesday, April 7, 2015, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Peter Petreczky
The venerable proton continues to play a central role in fundamental particle physics. Neutrinos scatter from protons in neutrino oscillation experiments, Weakly Interacting Massive Particles (WIMPs) are expected to scatter from protons in dark matter searches, and electrons or muons are bound by protons in precision atomic spectroscopy. Our understanding of the proton is an obstacle to the success of next generation experiments hoping to discover CP violation in the lepton sector and determine the neutrino mass hierarchy, discover the particle nature of dark matter, or reveal new interactions such as those that violate lepton universality. In this talk I present (i) an overview of the current state of knowledge in the neutrino sector, and theoretical advances that will determine a crucial missing ingredient in the predicted signal process of neutrino-nucleus scattering at a Long Baseline Neutrino Facility (ii) the first complete calculation of the scattering cross section of a proton on a static electroweak source, which determines WIMP-nucleus scattering rates at underground direct detection experiments and (iii) the status of the proton radius puzzle, whose most "mundane" resolution requires a 5 standard deviation shift in the value of the Rydberg constant. I describe how each of these problems has spurred the development of powerful new methods in effective quantum field theory.
516. Condensed-Matter Physics & Materials Science Seminar
"2-dimensional Superconductivity at the LaAlO3/SrTiO3 Interface"
Presented by Jean-Marc Triscone, DQMP, University of Geneva, Switzerland
Tuesday, April 7, 2015, 1:30 pm
ISB Bldg. 734, Conf. Rm. 201 (upstairs)
Hosted by: Ivan Bozovic
The interface between LaAlO3 and SrTiO3, two good band insulators, which was found in 2004 to be conducting [1], and, in some doping range, superconducting with a maximum critical temperature of about 200 mK [2] is attracting of lot of attention. The electronic structure of the system displays signatures of confinement and of the d-character of the carriers. This electron liquid has a thickness of a few nanometers at low temperatures and a low electronic density. Being naturally sandwiched between two insulators, it is ideal for performing electric field effect experiments that allow the carrier density to be tuned and the phase diagram of the system to be determined [3]. I will discuss in this presentation superconductivity, the phase diagram of the system and the link with bulk doped SrTiO3, spin orbit [4], and an approach that allows superconducting coupling between different gases to be studied. I will also discuss recent thermopower measurements that allow access to localized electronic states [5]. [1] A. Ohtomo, H. Y. Hwang, Nature 427, 423 (2004). [2] N. Reyren, S. Thiel, A. D. Caviglia, L. Fitting Kourkoutis, G. Hammerl, C. Richter, C. W. Schneider, T. Kopp, A.-S. Ruetschi, D. Jaccard, M. Gabay, D. A. Muller, J.-M. Triscone and J. Mannhart, Science 317, 1196 (2007). [3] A. Caviglia, S. Gariglio, N. Reyren, D. Jaccard, T. Schneider, M. Gabay, S. Thiel, G. Hammerl, J. Mannhart, and J.-M. Triscone, Nature 456, 624 (2008). [4] A.D. Caviglia, M. Gabay, S. Gariglio, N. Reyren, C. Cancellieri, and J.-M. Triscone, Physical Review 104, 126803 (2010). [5] I. Pallecchi, F. Telesio, D. Li, A. Fête, S. Gariglio, J.-M. Triscone, A. Filippetti, P. Delugas, V. Fiorentini, and D. Marré, to appear in Nature Communications.
517. Nuclear Physics Seminar
"New Studies of Elastic Nucleon Form Factors"
Presented by Dr. Seamus Riordan, Stony Brook University
Tuesday, April 7, 2015, 11 am
Small Seminar Room, Bldg. 510
Hosted by: Jin Huang
The electromagnetic form factors of the nucleon provide experimental access to the underlying charge and magnetic moment distributions arranged by the strong nuclear force. These form factors provide excellent testing grounds for QCD and QCD-inspired models and are fundamentally important in understanding non-perturbative strong force physics. By studying them over a broad range of momentum transfers, they provide insight into the underlying mechanisms relevant to the generation of nucleon structure. At low Q2 there is presently a controversy regarding the charge radius measurements of the proton. At high Q2, scaling of the form factors are presently being studied in the context of a transition from soft QCD interactions. In this talk I will provide an overview of our present experimental of elastic nucleon form factors, review their context within current theoretical models, discuss upcoming future measurements at Jefferson Lab, in particular the Super Bigbite program.
""Solid-State Laser Engineering for Inertial Confinement Fusion Laser Systems Applications""
Presented by Dr. Andrey Okishev
Friday, April 3, 2015, 4 pm
Bldg 911B., Large Conf.Rm., Rm. A202
"Solid-state laser concepts for ICF laser system applications including master oscillator, regenerative amplifier, OPO, and fiber-based front-end are discussed. Applications for the ICF laser system front-end, laser temporal diagnostics testing, laser damage testing, ASE suppression for OPCPA pump, energetic picosecond pulse generation without mode locking, cryogenic target layering, complex multi-FM pulses generation are described."
519. Nuclear Theory/RIKEN seminar
"Gravitational collapse, holography and hydrodynamics in extreme conditions"
Presented by Paul Chesler, Harvard University
Friday, April 3, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Soeren Schlichting
A remarkable observation from RHIC and the LHC is that the quark-gluon plasma produced in heavy-ion collisions behaves as a strongly coupled and nearly ideal liquid. Data also suggests that the debris produced by proton-nucleus collisions can also behave as a liquid. Understanding the dynamics responsible for the rapid equilibration of such tiny droplets is an outstanding problem. In recent years holography has emerged as a powerful tool to study non-equilibrium phenomena, mapping challenging quantum dynamics onto the classical dynamics of gravitational fields in one higher dimension. In the dual gravitational description the process of quark-gluon plasma formation and equilibration maps onto the process of gravitational collapse and black hole formation. I will describe how one can apply techniques and lessons learned from numerical relativity to holography and present recent work on holographic models of high energy collisions and the applicability of hydrodynamics to tiny droplets of quark-gluon plasma.
520. Particle Physics Seminar
"Measurement of the pion polarizability at COMPASS"
Presented by Jan Friedrich, Technische Universität München, Germany
Friday, April 3, 2015, 10 am
Small Seminar Room, Bldg. 510
Hosted by: Ketevi A. Assamagan
For more than a decade, the COMPASS experiment at the CERN Super Proton Synchrotron has been tackling the measurement of the electromagnetic polarizability of the charged pion, which describes the stiffness of the pion against deformation in electromagnetic fields. Previous experiments date back to the 1980's in Serpukhov (Russia), where the Primakoff method to study charged-pion interactions with quasi-real photons was first employed. Later also other techniques in photon-nucleon and photon-photon collisions were carried out at different machines. The COMPASS measurement demonstrates that the charged-pion polarizability is significantly smaller than the previous dedicated measurements, roughly by a factor two, with the smallest uncertainties realized so far. The pion polarisability is of fundamental interest in the low-energy sector of quantum chromodynamics. It is directly linked to the quark-gluon substructure and its dynamics in the lightest bound system of strong interaction.
521. Particle Physics Seminar
"Neutrino Oscillations with IceCube"
Presented by Tyce DeYoung, Michigan State University
Thursday, April 2, 2015, 3 pm
Small Seminar Room, Bldg. 510
Hosted by: Elizabeth Worcester
The IceCube Neutrino Observatory is the world's largest neutrino detector. Although designed to detect TeV " PeV scale neutrinos from astrophysical accelerators, IceCube's DeepCore infill array permits searches for dark matter and measurements of neutrino oscillations in the 10-100 GeV range. The most recent measurements of muon neutrino disappearance with IceCube DeepCore will be presented, and prospects for future neutrino physics measurements with IceCube and the proposed PINGU array will be discussed
522. RIKEN Lunch Seminar
"Spin-Orbit Coupling in an Unpolarized Heavy Nucleus"
Presented by Matt Sievert, BNL
Thursday, April 2, 2015, 12:30 pm
Building 510 Room 2-160
Hosted by: Daniel Pitonyak
The next-generation Electron-Ion Collider (EIC) will make high precision measurements of spin-dependent observables at high energies on nuclear targets. This unique nuclear physics laboratory will bring together access to the multitude of spin-spin and spin-orbit structures which can exist in hadronic targets, and the high color-charge densities which generate the most intense gluon fields permitted by quantum mechanics. The interplay between those two features gives rise to new physical mechanisms which translate these spin-orbit structures into the observed cross-sections, and it makes these mechanisms amenable to first-principles calculation. In this talk, I will discuss the spin-orbit structure of quarks within an unpolarized heavy nucleus in the quasi-classical approximation. The possibility of polarized nucleons with orbital motion inside the unpolarized nucleus generates nontrivial mixing between the spin-orbit structures of the nucleons, and the corresponding structures in the nucleus. This generic feature of a dense quasi-classical system leads to direct predictions testable at an EIC, and in principle allows direct access to the orbital angular momentum in the nucleus.
523. HET/RIKEN Seminar
"A Global Approach to Top-quark FCNCs"
Presented by Gauthier Durieux, Cornell University
Wednesday, April 1, 2015, 2 pm
Small Seminar Room, Bldg. 510
Hosted by: Chien-Yi Chen
524. Physics Colloquium
"Hot Jupiters: astrophysical laboratories for extreme weather"
Presented by Rosalba Perna, Stony Brook University
Tuesday, March 31, 2015, 3:30 pm
Large Seminar Room, Bldg. 510
Hosted by: Peter Petreczky
Hot Jupiters, a class of exoplanets orbiting in the proximity of their par
| 2017-10-17T20:39:46 |
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https://www.usgs.gov/center-news/volcano-watch-least-some-footprints-kau-desert-are-older-1790
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# Volcano Watch — At least some footprints in the Kau Desert are older than 1790
Release Date:
Luckily, Hawaii experiences volcanic ash much less often than it does lava flows. When it comes, though, it can be anything from a nuisance to a disaster for those beneath the falling ash. The most recent ash fall, from Halemaumau in 1924, was minor but affected residents from Makuu to Pahala. The latest major ash fall, in 1790, resulted from explosions at the summit of Kilauea.
HVO and Smithsonian volcanologists are investigating past ash eruptions to understand better their consequences and cause. This many-sided study ranges from the scientifically esoteric to the socially serious. Today's column describes two of the most recent findings, one of interest to the local community and the other a reminder to volcanologists that it's not always as simple as we'd like.<> The human footprints in the Kau Desert are internationally renowned. They were made in two different layers of wet ash, each containing numerous small spherical pellets of ash termed accretionary lapilli. Each layer has mud cracks and so must have dried in the sun before it was covered with more ash. This observation shows that the two layers are from two different eruptions, not surprising, since glassy sand-a different kind of ash-occurs between the two layers and suggests yet another explosion.
The footprints were discovered (or perhaps rediscovered) in 1920 by HVO seismologist Ruy Finch. Thomas Jaggar thought that all of the prints were made in 1790 by Keoua's warriors, many of whom perished that year during an explosion. The thinking of Jaggar's time was that few people ever visited the summit area of Kilauea, so the odds seemed high that the warriors made the footprints. Jaggar recognized but didn't worry about the fact that the footprints occurred in two distinct layers.
Recent discoveries by national park archaeologists and HVO volcanologists raise serious doubts about this interpretation. Archaeologists found ample evidence for people being in the area often, and volcanologists showed that the deposits containing the ash layers resulted from a number of eruptions between 1500 and 1790. The question now becomes this: Were the footprint-bearing ash layers deposited in 1790 or at an earlier time?
By tracing individual beds of ash, HVO scientists can now show that the earlier footprint-bearing ash was formed by eruptions before 1790, perhaps decades or more. This was done by identifying the deposits of the 1790 eruption (some of which are perhaps even older than 1790) and finding that the first footprints occur below those deposits. The age of the younger footprints is still uncertain, and we have more work to do before we can say whether or not they formed in 1790.
This work was comparatively easy, because the ash fell on bare lava flows and formed continuous layers of consistent thickness, much as snow falls on an empty parking lot. But imagine snow falling on a parking lot filled with cars. Some cars leave, some stay, some are bigger than others, some are parked at odd angles, the snow slides off some-uneven, discontinuous snow cover results. The same is true for ash falling on thick forest; the resulting deposits can be very challenging to understand.
An example comes from a trench recently excavated between KMC and Keauhou Ranch. Near the caldera, the sides of the trench showed obvious ash layers in deposits ranging in age from several hundred to several thousand years. Beyond the Volcano Golf Course Subdivision, however, the deposits are very complicated. Individual layers are discontinuous or even absent in many places. Lots of organic debris is intermixed in the deposits. Most likely, ash fell on thick forest with tangles of logs on the ground, such as in the nearby Olaa Tract of the national park today. Ash became hung up on leaves and branches, sifting down at various times in the wind and rain. Some ash never reached the ground below logs. When the logs rotted away, ash slumped and sloughed to the ground in a chaotic way, mixing with organic debris. The end result is a messy deposit that makes the volcanologist long for the desert.
### Volcano Activity Update
Eruptive activity of Kilauea Volcano continued unabated at the Puu Oo vent during the past week. From the end of the Chain of Craters road, lava can be seen flowing down Pulama pali and cascading over Paliuli. Many surface breakouts can be found in the coastal flats, and the National Park Service is allowing visitors to hike out and get up close to these active flows. At 6:17:42 a.m. on September 3, lava entered the ocean near the east end of the Wilipea bench. The ocean entry activity is now taking place along the leading edge of the Wilipea bench.
One earthquake was reported felt during the week ending on September 5. A resident of Glenwood felt an earthquake at 4:00 p.m. on Thursday, August 29. The magnitude-2.2 earthquake was located 27 km (16.2 mi) south of Ka`ena Point at a depth of 35 km (21 mi).
| 2021-05-08T22:33:02 |
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|
https://par.nsf.gov/biblio/10347847-observational-signatures-gamma-rays-from-bright-blazars-wakefield-theory
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Observational signatures of gamma-rays from bright blazars and wakefield theory
ABSTRACT Gamma-ray observations have revealed strong variability in blazar luminosities in the gamma-ray band over time-scales as short as minutes. We show, for the first time, that the correlation of the spectrum with intensity is consistent with the behaviour of the luminosity variation of blazar spectral energy distributions (SEDs) along a blazar sequence for low synchrotron peak blazars. We show that the observational signatures of variability with flux are consistent with wakefield acceleration of electrons initiated by instabilities in the blazar accretion disc. This mechanism reproduces the observed time variations as short as 100 s. The wakefield mechanism also predicts a reduction of the electron spectral index with increased gamma-ray luminosity, which could be detected in higher energy observations well above the inverse Compton peak.
Authors:
; ; ; ;
Award ID(s):
Publication Date:
NSF-PAR ID:
10347847
Journal Name:
Monthly Notices of the Royal Astronomical Society
Volume:
493
Issue:
2
Page Range or eLocation-ID:
2229 to 2237
ISSN:
0035-8711
National Science Foundation
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| 2023-02-05T02:35:27 |
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https://zbmath.org/authors/?q=ai%3Aagarwal.ravi-p
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zbMATH — the first resource for mathematics
Agarwal, Ravi P.
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Author ID: agarwal.ravi-p Published as: Agarval, Ravi P.; Agarwal; Agarwal, R.; Agarwal, R. P.; Agarwal, Ravi; Agarwal, Ravi P.; Agarwal, Ravi P.; Agarwal, Ravi. P.; Argawal, Ravi P. Homepage: http://www.tamuk.edu/artsci/math/faculty/agarwal.html External Links: MGP · Math-Net.Ru · Wikidata · ORCID · ResearchGate · dblp · GND
Documents Indexed: 1,650 Publications since 1972, including 61 Books Biographic References: 1 Publication
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81 single-authored 623 O’Regan, Donal 131 Wong, Patricia J. Y. 102 Grace, Said Rezk 54 Bohner, Martin J. 45 Saker, Samir H. 42 Khristova, Snezhana G. 38 Ahmad, Bashir 33 Jiang, Daqing 29 Wei, Li 27 Li, Tongxing 25 Al-saedi, Ahmed Eid Salem 25 Cho, Yeol Je 25 Pang, Peter Y. H. 25 Wang, Chao 24 Lu, Haishen 23 Staněk, Svatoslav 23 Yan, Baoqiang 22 Lakshmikantham, Vangipuram 22 Sen, Syamal Kumar 22 Zhang, Chenghui 20 Benchohra, Mouffak 19 Perera, Kanishka 19 Thandapani, Ethiraju 17 Karapınar, Erdal 16 Băleanu, Dumitru I. 16 Nashine, Hemant Kumar 15 Pinelas, Sandra 14 Guo, Chengjun 14 Ryoo, Cheon Seoung 14 Sheng, Qin 14 Wong, Fu-Hsiang 13 Li, Wan-Tong 13 Lupulescu, Vasile 13 Mustafa, Octavian G. 13 Shahzad, Naseer 12 de la Sen, Manuel 12 Dshalalow, Jewgeni H. 12 Muslim, Malik 11 Agarwal, Ritu 11 Ahmad, Izhar 11 Dragomir, Sever Silvestru 11 Ntouyas, Sotiris K. 11 Verma, Ram U. 10 Cuevas, Claudio 10 Farajzadeh, Ali P. 10 Kang, Shin Min 10 Özbekler, Abdullah 10 Yu, Hengguo 10 Zafer, Ağacık 9 Amini-Harandi, Alireza 9 Balaj, Mircea 9 Papageorgiou, Nikolaos S. 9 Qu, Ruibin 9 Rahman, Ghaus Ur 9 Shakhmurov, Veli B. 7 Chen, Jinhai 7 Domoshnitsky, Alexander I. 7 El-Gebeily, Mohamed A. 7 Filippakis, Michael E. 7 Huang, Nan-Jing 7 Kim, Taekyun 7 Kim, Youngho 7 Li, Chun 7 Marin, Marin I. 7 Otero-Espinar, Victoria 7 Pečarić, Josip 7 Qin, Xiaolong 7 Samet, Bessem 7 Taoudi, Mohamed Aziz 7 Usmani, Riaz A. 7 Wang, Guotao 7 Xu, Yuantong 7 Zhong, Shou-Ming 6 Ding, Shusen 6 Fan, Meng 6 Goswami, Mahesh Puri 6 Ibeas, Asier 6 Manojlović, Jelena V. 6 Osman, Mahmoud M. 6 Precup, Radu 6 Sahu, Daya Ram 6 Wang, Yuanming 6 Xu, Xiaojie 6 Zhang, Lihong 6 Zhang, Weinian 6 Zhou, Haiyun 5 Akın-Bohner, Elvan 5 Banaś, Józef 5 Chow, Y. M. 5 Chu, Jifeng 5 de Andrade, Bruno 5 Dhage, Bapurao C. 5 Hamani, Samira 5 Kadelburg, Zoran 5 Karakoç, Fatma 5 Leela, Srinivasa G. 5 Meehan, Maria 5 Roldán-López-de-Hierro, Antonio-Francisco 5 Saadati, Reza 5 Salahuddin ...and 535 more Co-Authors
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Serials
86 Computers & Mathematics with Applications 68 Applied Mathematics Letters 67 Mathematical and Computer Modelling 64 Advances in Difference Equations 58 Journal of Mathematical Analysis and Applications 56 Applied Mathematics and Computation 41 Applicable Analysis 41 Fixed Point Theory and Applications 39 Journal of Computational and Applied Mathematics 38 Dynamic Systems and Applications 37 Journal of Inequalities and Applications 36 Boundary Value Problems 31 Dynamics of Continuous, Discrete & Impulsive Systems. Series A. Mathematical Analysis 22 Mathematical Inequalities & Applications 20 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 20 Journal of Nonlinear and Convex Analysis 19 Memoirs on Differential Equations and Mathematical Physics 18 Georgian Mathematical Journal 17 Journal of Applied Mathematics and Computing 16 Advances in Mathematical Sciences and Applications 16 Abstract and Applied Analysis 15 Functional Differential Equations 14 Nonlinear Analysis. Theory, Methods & Applications 13 Journal of Difference Equations and Applications 12 Advanced Studies in Contemporary Mathematics (Kyungshang) 11 Mathematical Methods in the Applied Sciences 11 Neural, Parallel & Scientific Computations 11 Communications in Applied Analysis 11 Nonlinear Functional Analysis and Applications 10 Journal of Mathematical and Physical Sciences 10 Topological Methods in Nonlinear Analysis 9 Acta Mathematica Hungarica 9 Journal of Applied Mathematics and Stochastic Analysis 9 Aequationes Mathematicae 9 International Journal of Computer Mathematics 9 Electronic Journal of Differential Equations (EJDE) 9 Nonlinear Studies 9 Communications in Nonlinear Science and Numerical Simulation 9 Journal of Nonlinear Science and Applications 8 Rocky Mountain Journal of Mathematics 8 Analele Ştiinţifice ale Universităţii Al. I. Cuza din Iaşi. (Serie Nouă.) Secţiunea Ia. Matematică-Informatică 8 Journal of Differential Equations 8 Mathematische Nachrichten 8 Bulletin of the Institute of Mathematics. Academia Sinica 7 Journal of the Franklin Institute 7 Archivum Mathematicum 7 Journal of Optimization Theory and Applications 7 Proceedings of the American Mathematical Society 7 Zeitschrift für Analysis und ihre Anwendungen 7 Fractional Calculus & Applied Analysis 7 Nonlinear Analysis Forum 7 Dynamics of Continuous, Discrete & Impulsive Systems. Series B. Applications & Algorithms 7 Differential Equations and Applications 7 Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A: Matemáticas. RACSAM 6 Funkcialaj Ekvacioj. Serio Internacia 6 Acta Applicandae Mathematicae 6 Journal of Integral Equations and Applications 6 Applications of Mathematics 6 Panamerican Mathematical Journal 6 Communications on Applied Nonlinear Analysis 6 Electronic Journal of Qualitative Theory of Differential Equations 6 Nonlinear Analysis. Real World Applications 5 Bulletin of the Australian Mathematical Society 5 Fasciculi Mathematici 5 The Journal of the Indian Mathematical Society. New Series 5 Proceedings of the Edinburgh Mathematical Society. Series II 5 Mathematical Problems in Engineering 5 Analysis (München) 5 Acta Mathematica Sinica. English Series 5 Cubo 5 Journal of Fixed Point Theory and Applications 4 Indian Journal of Pure & Applied Mathematics 4 Glasgow Mathematical Journal 4 Numerical Functional Analysis and Optimization 4 Results in Mathematics 4 Asymptotic Analysis 4 The Canadian Applied Mathematics Quarterly 4 Bulletin of the Belgian Mathematical Society - Simon Stevin 4 Journal of Applied Analysis 4 The ANZIAM Journal 4 Differential Equations 4 Archives of Inequalities and Applications 4 Carpathian Journal of Mathematics 4 International Journal of Dynamical Systems and Differential Equations 4 Discontinuity, Nonlinearity, and Complexity 3 Ukraïns’kyĭ Matematychnyĭ Zhurnal 3 Annales Polonici Mathematici 3 Canadian Mathematical Bulletin 3 Czechoslovak Mathematical Journal 3 Demonstratio Mathematica 3 International Journal of Mathematics and Mathematical Sciences 3 Journal of the Korean Mathematical Society 3 Mathematics Seminar Notes 3 Mathematica Slovaca 3 Mathematika 3 Annales Societatis Mathematicae Polonae. Seria I. Commentationes Mathematicae 3 Acta Mathematicae Applicatae Sinica 3 Bulletin of the Korean Mathematical Society 3 Stochastic Analysis and Applications 3 Differential and Integral Equations ...and 177 more Serials
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Fields
808 Ordinary differential equations (34-XX) 382 Operator theory (47-XX) 275 Difference and functional equations (39-XX) 172 Real functions (26-XX) 138 Partial differential equations (35-XX) 135 Numerical analysis (65-XX) 130 Integral equations (45-XX) 102 General topology (54-XX) 63 Calculus of variations and optimal control; optimization (49-XX) 50 Biology and other natural sciences (92-XX) 43 Systems theory; control (93-XX) 38 Approximations and expansions (41-XX) 32 Global analysis, analysis on manifolds (58-XX) 29 General and overarching topics; collections (00-XX) 26 Functional analysis (46-XX) 25 Special functions (33-XX) 23 Dynamical systems and ergodic theory (37-XX) 23 Operations research, mathematical programming (90-XX) 22 Probability theory and stochastic processes (60-XX) 17 Number theory (11-XX) 15 Functions of a complex variable (30-XX) 14 Abstract harmonic analysis (43-XX) 12 Algebraic topology (55-XX) 12 Fluid mechanics (76-XX) 10 Mechanics of deformable solids (74-XX) 9 Harmonic analysis on Euclidean spaces (42-XX) 8 History and biography (01-XX) 8 Integral transforms, operational calculus (44-XX) 7 Computer science (68-XX) 6 Differential geometry (53-XX) 6 Statistics (62-XX) 4 Measure and integration (28-XX) 4 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 3 Manifolds and cell complexes (57-XX) 3 Quantum theory (81-XX) 3 Information and communication theory, circuits (94-XX) 2 Combinatorics (05-XX) 2 Group theory and generalizations (20-XX) 2 Potential theory (31-XX) 2 Several complex variables and analytic spaces (32-XX) 2 Mechanics of particles and systems (70-XX) 2 Classical thermodynamics, heat transfer (80-XX) 1 Mathematical logic and foundations (03-XX) 1 Field theory and polynomials (12-XX) 1 Algebraic geometry (14-XX) 1 Linear and multilinear algebra; matrix theory (15-XX) 1 Sequences, series, summability (40-XX)
Citations contained in zbMATH Open
1,314 Publications have been cited 18,050 times in 10,230 Documents Cited by Year
Difference equations and inequalities. Theory, methods, and applications. Zbl 0925.39001
Agarwal, Ravi P.
1992
Difference equations and inequalities: theory, methods, and applications. 2nd, revised and expanded ed. Zbl 0952.39001
Agarwal, Ravi P.
2000
A survey on existence results for boundary value problems of nonlinear fractional differential equations and inclusions. Zbl 1198.26004
Agarwal, Ravi P.; Benchohra, Mouffak; Hamani, Samira
2010
Basic calculus on time scales and some of its applications. Zbl 0927.39003
Agarwal, Ravi P.; Bohner, Martin
1999
Advanced topics in difference equations. Zbl 0878.39001
Agarwal, Ravi P.; Wong, Patricia J. Y.
1997
Dynamic equations on time scales: A survey. Zbl 1020.39008
Agarwal, Ravi; Bohner, Martin; O’Regan, Donal; Peterson, Allan
2002
Generalized contractions in partially ordered metric spaces. Zbl 1140.47042
Agarwal, Ravi P.; El-Gebeily, M. A.; O’Regan, Donal
2008
Inequalities on time scales: a survey. Zbl 1021.34005
Agarwal, R.; Bohner, M.; Peterson, A.
2001
Positive solutions of differential, difference and integral equations. Zbl 1157.34301
Agarwal, Ravi P.; O’Regan, Donal; Wong, Patricia J. Y.
1999
On the concept of solution for fractional differential equations with uncertainty. Zbl 1188.34005
Agarwal, Ravi P.; Lakshmikantham, V.; Nieto, Juan J.
2010
Boundary value problems for higher order differential equations. Zbl 0619.34019
Agarwal, Ravi P.
1986
Eigenvalue intervals and double positive solutions of certain discrete boundary value problems. Zbl 0923.39002
Wong, P. J. Y.; Agarwal, R. P.
1999
On the existence of positive solutions of higher order difference equations. Zbl 0914.39005
Wong, P. J. Y.; Agarwal, R. P.
1997
Existence of fractional neutral functional differential equations. Zbl 1189.34152
Agarwal, R. P.; Zhou, Yong; He, Yunyun
2010
Fixed point theory and applications. Zbl 0960.54027
Agarwal, Ravi P.; Meehan, Maria; O’Regan, Donal
2001
Iterative construction of fixed points of nearly asymptotically nonexpansive mappings. Zbl 1134.47047
Agarwal, R. P.; O’Regan, Donal; Sahu, D. R.
2007
Applications of $$q$$-calculus in operator theory. Zbl 1273.41001
Aral, Ali; Gupta, Vijay; Agarwal, Ravi P.
2013
Oscillation theory for difference and functional differential equations. Zbl 0954.34002
Agarwal, Ravi P.; Grace, Said R.; O’Regan, Donal
2000
Positive solutions for Dirichlet problems of singular nonlinear fractional differential equations. Zbl 1206.34009
Agarwal, Ravi P.; O’Regan, Donal; Staněk, Svatoslav
2010
Two inequalities for differentiable mappings and applications to special means of real numbers and to trapezoidal formula. Zbl 0938.26012
Dragomir, S. S.; Agarwal, R. P.
1998
A survey on semilinear differential equations and inclusions involving Riemann-Liouville fractional derivative. Zbl 1182.34103
Agarwal, Ravi P.; Belmekki, Mohammed; Benchohra, Mouffak
2009
Infinite interval problems for differential, difference and integral equations. Zbl 0988.34002
Agarwal, Ravi P.; O’Regan, Donal
2001
Multiple positive solutions of singular and nonsingular discrete problems via variational methods. Zbl 1070.39005
Agarwal, Ravi P.; Perera, Kanishka; O’Regan, Donal
2004
On Gel’fand’s method of chasing for solving multipoint boundary value problems. Zbl 0598.65062
Agarwal, R. P.
1986
On fourth order boundary value problems arising in beam analysis. Zbl 0715.34032
Agarwal, Ravi P.
1989
Fixed point theory for Lipschitzian-type mappings with applications. Zbl 1176.47037
Agarwal, Ravi P.; O’Regan, Donal; Sahu, D. R.
2009
Oscillation theory for second order linear, half-linear, superlinear and sublinear dynamic equations. Zbl 1073.34002
Agarwal, Ravi P.; Grace, Said R.; O’Regan, Donal
2002
Sturm-Liouville eigenvalue problems on time scales. Zbl 0938.34015
Agarwal, Ravi P.; Bohner, Martin; Wong, Patricia J. Y.
1999
Multiple positive solutions of singular discrete $$p$$-Laplacian problems via variational methods. Zbl 1098.39001
Agarwal, Ravi P.; Perera, Kanishka; O’Regan, Donal
2005
Nonoscillation and oscillation. Theory for functional differential equations. Zbl 1068.34002
Agarwal, Ravi P.; Bohner, Martin; Li, Wan-Tong
2004
Convergence estimates in approximation theory. Zbl 1295.41002
Gupta, Vijay; Agarwal, Ravi P.
2014
Generalization of a retarded Gronwall-like inequality and its applications. Zbl 1078.26010
Agarwal, Ravi P.; Deng, Shengfu; Zhang, Weinian
2005
Nonlinear fractional integro-differential equations on unbounded domains in a Banach space. Zbl 1302.45019
Zhang, Lihong; Ahmad, Bashir; Wang, Guotao; Agarwal, Ravi P.
2013
Nonoscillation theory of functional differential equations with applications. Zbl 1253.34002
Agarwal, Ravi P.; Berezansky, Leonid; Braverman, Elena; Domoshnitsky, Alexander I.
2012
Nonlinear boundary value problems on time scales. Zbl 0995.34016
Agarwal, Ravi P.; O’Regan, Donal
2001
Weighted pseudo-almost periodic solutions of a class of semilinear fractional differential equations. Zbl 1248.34004
Agarwal, Ravi P.; de Andrade, Bruno; Cuevas, Claudio
2010
Focal boundary value problems for differential and difference equations. Zbl 0914.34001
Agarwal, Ravi P.
1998
Oscillation criteria for second-order nonlinear neutral delay dynamic equations. Zbl 1062.34068
Agarwal, Ravi P.; O’Regan, Donal; Saker, S. H.
2004
Stability of functional equations in single variable. Zbl 1053.39042
Agarwal, Ravi P.; Xu, Bing; Zhang, Weinian
2003
Existence theory for anti-periodic boundary value problems of fractional differential equations and inclusions. Zbl 1228.34009
2011
Multiple nonnegative solutions for second order impulsive differential equations. Zbl 1047.34008
Agarwal, Ravi P.; O’Regan, Donal
2000
Uniqueness and nonuniqueness criteria for ordinary differential equations. Zbl 0785.34003
Agarwal, R. P.; Lakshmikantham, V.
1993
Nonlinear superlinear singular and nonsingular second order boundary value problems. Zbl 0902.34015
Agarwal, Ravi P.; O’Regan, Donal
1998
Eigenvalues and the one-dimensional $$p$$-Laplacian. Zbl 1002.34019
Agarwal, Ravi P.; Lü, Haishen; O’Regan, Donal
2002
Iterative methods for a fourth order boundary value problem. Zbl 0541.65055
Agarwal, Ravi P.; Chow, Y. M.
1984
Error inequalities in polynomial interpolation and their applications. Zbl 0881.41001
Agarwal, Ravi P.; Wong, Patricia J. Y.
1993
Existence results and the monotone iterative technique for systems of nonlinear fractional differential equations. Zbl 1244.34008
Wang, Guotao; Agarwal, Ravi P.; Cabada, Alberto
2012
Discrete oscillation theory. Zbl 1084.39001
Agarwal, Ravi P.; Bohner, Martin; Grace, Said R.; O’Regan, Donal
2005
Existence results for differential equations with fractional order and impulses. Zbl 1178.26006
Agarwal, Ravi P.; Benchohra, Mouffak; Slimani, Boualem Attou
2008
Oscillation of second order delay dynamic equations. Zbl 1126.39003
Agarwal, R. P.; Bohner, M.; Saker, S. H.
2005
Mathematics-teaching and research on the horns of a dilemma. Zbl 1006.00501
Agarwal, R. P.
2000
An existence result for a superlinear fractional differential equation. Zbl 1200.34004
Băleanu, Dumitru; Mustafa, Octavian G.; Agarwal, Ravi P.
2010
The oscillation of perturbed functional differential equations. Zbl 0969.34062
Agarwal, R. P.; Grace, S. R.
2000
Nonlinear Urysohn discrete equations on the infinite interval: a fixed-point approach. Zbl 1003.39017
Agarwal, R. P.; O’Regan, D.
2001
Singular boundary value problems for superlinear second order ordinary and delay differential equations. Zbl 0863.34022
Agarwal, Ravi P.; O’Regan, Donal
1996
On multipoint boundary value problems for discrete equations. Zbl 0539.39005
Agarwal, Ravi P.
1983
Singular boundary value problems for first and second order impulsive differential equations. Zbl 1073.34025
Agarwal, Ravi P.; Franco, Daniel; O’Regan, Donal
2005
Stability analysis of fractional differential system with Riemann-Liouville derivative. Zbl 1202.34020
Qian, Deliang; Li, Changpin; Agarwal, Ravi P.; Wong, Patricia J. Y.
2010
Oscillation theory for second order dynamic equations. Zbl 1043.34032
Agarwal, Ravi P.; Grace, Said R.; O’Regan, Donal
2003
Sensitivity analysis for strongly nonlinear quasi-variational inclusions. Zbl 0960.47035
Agarwal, R. P.; Cho, Yeol Je; Huang, Nan Jing
2000
Lyapunov and Wirtinger inequalities. Zbl 1062.34005
Lee, Chung-Fen; Yeh, Cheh-Chih; Hong, Chen-Huang; Agarwal, R. P.
2004
Half-linear dynamic equations. Zbl 1056.34049
Agarwal, R. P.; Bohner, M.; Řehák, P.
2003
Periodicity and stability in periodic $$n$$-species Lotka-Volterra competition system with feedback controls and deviating arguments. Zbl 1047.34080
Fan, Meng; Wang, Ke; Wong, Patricia J. Y.; Agarwal, Ravi P.
2003
Morse theoretic aspects of $$p$$-Laplacian type operators. Zbl 1192.58007
Perera, Kanishka; Agarwal, Ravi P.; O’Regan, Donal
2010
Recent progress on stage-structured population dynamics. Zbl 1077.92516
Liu, Shengqiang; Chen, Lansun; Agarwal, R.
2002
Oscillatory behavior of solutions of certain second order nonlinear differential equations. Zbl 0855.34039
Wong, Patricia J. Y.; Agarwal, Ravi P.
1996
Boundary value problems for fractional differential equations. Zbl 1179.26011
Agarwal, Ravi P.; Benchohra, Mouffak; Hamani, Samira
2009
Oscillation criteria for second-order retarded differential equations. Zbl 0902.34061
Agarwal, R. P.; Shieh, Shiow-Ling; Yeh, Cheh-Chih
1997
Lidstone polynomials and boundary value problems. Zbl 0682.65049
Agarwal, R. P.; Wong, P. J. Y.
1989
On fractional integro-differential equations with state-dependent delay. Zbl 1228.35262
Agarwal, Ravi P.; De Andrade, Bruno; Siracusa, Giovana
2011
On Simpson’s inequality and applications. Zbl 0976.26012
Dragomir, S. S.; Agarwal, R. P.; Cerone, P.
2000
Oscillation criteria for certain $$n$$th order differential equations with deviating arguments. Zbl 0997.34060
Agarwal, Ravi P.; Grace, Said R.; O’Regan, Donal
2001
Existence theory for single and multiple solutions to singular positone boundary value problems. Zbl 0999.34018
Agarwal, Ravi P.; O’Regan, Donal
2001
On the oscillation of fractional differential equations. Zbl 1273.34007
Grace, Said R.; Agarwal, Ravi P.; Wong, Patricia J. Y.; Zafer, Ağacık
2012
On $$L^{p}$$-solutions for a class of sequential fractional differential equations. Zbl 1235.34008
Băleanu, Dumitru; Mustafa, Octavian G.; Agarwal, Ravi P.
2011
Multiplicity results for singular conjugate, focal, and $$(N,P)$$ problems. Zbl 0978.34018
Agarwal, Ravi P.; O’Regan, Donal
2001
Opial inequalities with applications in differential and difference equations. Zbl 0821.26013
Agarwal, Ravi P.; Pang, Peter Y. H.
1995
Positive solutions for mixed problems of singular fractional differential equations. Zbl 1232.26005
Agarwal, Ravi P.; O’Regan, Donal; Staněk, Svatoslav
2012
Inequalities for differential forms. Zbl 1184.53001
Agarwal, Ravi P.; Ding, Shusen; Nolder, Craig
2009
A multiplicity result for second order impulsive differential equations via the Leggett Williams fixed point theorem. Zbl 1070.34042
Agarwal, Ravi P.; O’Regan, Donal
2005
Interval oscillation criteria for second-order nonlinear differential equations with damping. Zbl 0959.34026
Li, Wan-Tong; Agarwal, R. P.
2000
Positive solutions and nonlinear eigenvalue problems for third-order difference equations. Zbl 0933.39003
Agarwal, R. P.; Henderson, J.
1998
On the solution set for a class of sequential fractional differential equations. Zbl 1216.34004
Băleanu, Dumitru; Mustafa, Octavian G.; Agarwal, Ravi P.
2010
Twin solutions to singular Dirichlet problems. Zbl 0946.34022
Agarwal, Ravi P.; O’Regan, Donal
1999
Boundary value problems for discrete equations. Zbl 0890.39001
Agarwal, R. P.; O’Regan, D.
1997
Multiple positive solutions to superlinear periodic boundary value problems with repulsive singular forces. Zbl 1042.34047
Jiang, Daqing; Chu, Jifeng; O’Regan, Donal; Agarwal, Ravi P.
2003
Quadratic functionals for second order matrix equations on time scales. Zbl 0938.49001
Agarwal, Ravi P.; Bohner, Martin
1998
Periodic solutions of first order linear difference equations. Zbl 0871.39002
Agarwal, R. P.; Popenda, J.
1995
Remarks on some coupled fixed point theorems in $$G$$-metric spaces. Zbl 1305.54046
Agarwal, Ravi P.; Karapınar, Erdal
2013
The oscillation of certain higher-order functional differential equations. Zbl 1070.34083
Agarwal, R. P.; Grace, S. R.; O’Regan, D.
2003
Krasnosel’skii and Ky Fan type fixed point theorems in ordered Banach spaces. Zbl 1219.47079
Hussain, N.; Khan, A. R.; Agarwal, R. P.
2010
Maximal regular boundary value problems in Banach-valued weighted space. Zbl 1081.35129
Agarwal, Ravi P.; Bohner, Martin; Shakhmurov, Veli B.
2005
Sensitivity analysis for a new system of generalized nonlinear mixed quasi-variational inclusions. Zbl 1056.49008
Agarwal, R. P.; Huang, Nan-Jing; Tan, Man-Yi
2004
Eigenvalues of Lidstone boundary value problems. Zbl 0933.65089
Wong, Patricia J. Y.; Agarwal, Ravi P.
1999
On the existence of solutions of singular boundary value problems for higher order difference equations. Zbl 0861.39002
Wong, Patricia J. Y.; Agarwal, Ravi P.
1997
Nonlocal nonlinear integrodifferential equations of fractional orders. Zbl 1277.35337
Debbouche, Amar; Baleanu, Dumitru; Agarwal, Ravi P.
2012
A survey of Lyapunov functions, stability and impulsive Caputo fractional differential equations. Zbl 1343.34006
Agarwal, Ravi; Hristova, Snezhana; O’Regan, Donal
2016
Generalized nonlinear mixed implicit quasi-variational inclusions with set-valued mappings. Zbl 1034.47032
Agarwal, R. P.; Huang, N. J.; Cho, Y. J.
2002
A fixed-point approach for nonlinear discrete boundary value problems. Zbl 0933.39004
Agarwal, R. P.; O’Regan, D.
1998
On type of periodicity and ergodicity to a class of fractional order differential equations. Zbl 1194.34007
Agarwal, Ravi P.; De Andrade, Bruno; Cuevas, Claudio
2010
Special functions and analysis of differential equations. Zbl 1441.33001
Agarwal, Praveen (ed.); Agarwal, Ravi P. (ed.); Ruzhansky, Michael (ed.)
2020
A survey: $$F$$-contractions with related fixed point results. Zbl 07240943
Karapınar, Erdal; Fulga, Andreea; Agarwal, Ravi P.
2020
A study of fractional Lotka-Volterra population model using Haar wavelet and Adams-Bashforth-Moulton methods. Zbl 1452.65124
Kumar, Sunil; Kumar, Ranbir; Agarwal, Ravi P.; Samet, Bessem
2020
Almost automorphic functions on semigroups induced by complete-closed time scales and application to dynamic equations. Zbl 1431.34100
Wang, Chao; Agarwal, Ravi P.
2020
$$F$$-contraction mappings on metric-like spaces in connection with integral equations on time scales. Zbl 1440.54030
Agarwal, Ravi P.; Aksoy, Ümit; Karapınar, Erdal; Erhan, İnci M.
2020
Geodesic sandwich theorem with an application. Zbl 1441.26007
Shaikh, Absos Ali; Agarwal, Ravi P.; Mondal, Chandan Kumar
2020
Lyapunov-type inequalities for Lidstone boundary value problems on time scales. Zbl 1437.34092
Agarwal, Ravi P.; Oğuz, Arzu Denk; Özbekler, Abdullah
2020
A new high order numerical approach for a class of nonlinear derivative dependent singular boundary value problems. Zbl 07106372
2019
A higher integrability theorem from a reverse weighted inequality. Zbl 1441.26010
Saker, Samir; O’Regan, Donal; Agarwal, Ravi
2019
Analytic solution of time fractional Boussinesq equation for groundwater flow in unconfined aquifer. Zbl 1432.35217
2019
Mathematical analysis of giving up smoking model via harmonic mean type incidence rate. Zbl 1428.92115
Rahman, Ghaus Ur; Agarwal, Ravi P.; Din, Qamar
2019
Calculus of fuzzy vector-valued functions and almost periodic fuzzy vector-valued functions on time scales. Zbl 1423.26059
Wang, Chao; Agarwal, Ravi P.; O’Regan, Donal
2019
Optimal control & dynamical aspects of a stochastic pine wilt disease model. Zbl 1412.92270
Agarwal, Ravi P.; Badshah, Qaisar; ur Rahman, Ghaus; Islam, Saeed
2019
Levinson type inequalities and their extensions via convexity on time scales. Zbl 1409.26016
Saker, S. H.; Osman, M. M.; O’Regan, D.; Agarwal, R. P.
2019
Stability analysis and robust synchronization of fractional-order competitive neural networks with different time scales and impulsive perturbations. Zbl 1451.93315
Pratap, Anbalagan; Raja, Ramachandran; Agarwal, Ravi P.; Cao, Jinde
2019
Positive solutions for a semipositone singular Riemann-Liouville fractional differential problem. Zbl 07168392
Agarwal, Ravi P.; Luca, Rodica
2019
Existence of solutions of BVPs for impulsive fractional Langevin equations involving Caputo fractional derivatives. Zbl 1440.34009
Liu, Yuji; Agarwal, Ravi
2019
A Darbo fixed point theory approach towards the existence of a functional integral equation in a Banach algebra. Zbl 1428.45006
Sen, Mausumi; Saha, Dipankar; Agarwal, R. P.
2019
Ground state and bounded state solution for the nonlinear fractional Choquard-Schrödinger-Poisson system. Zbl 1431.35183
Teng, Kaimin; Agarwal, Ravi P.
2019
A compact finite difference method for a general class of nonlinear singular boundary value problems with Neumann and Robin boundary conditions. Zbl 1429.65165
2019
Solutions of the nonlinear integral equation and fractional differential equation using the technique of a fixed point with a numerical experiment in extended $$b$$-metric space. Zbl 1425.47016
Abdeljawad, Thabet; Agarwal, Ravi P.; Karapınar, Erdal; Kumari, P. Sumati
2019
Basic concepts of Riemann-Liouville fractional differential equations with non-instantaneous impulses. Zbl 1425.34003
Agarwal, Ravi; Hristova, Snezhana; O’Regan, Donal
2019
Non-optimal fourth-order and optimal sixth-order B-spline collocation methods for Lane-Emden boundary value problems. Zbl 07106373
Roul, Pradip; Thula, Kiran; Agarwal, Ravi
2019
Mittag-Leffler stability for non-instantaneous impulsive Caputo fractional differential equations with delays. Zbl 07093132
Agarwal, Ravi; Hristova, Snezhana; O’Regan, Donal
2019
A fast-converging recursive approach for Lane-Emden type initial value problems arising in astrophysics. Zbl 1436.65084
2019
A modified numerical scheme and convergence analysis for fractional model of Lienard’s equation. Zbl 1404.34007
Kumar, Devendra; Agarwal, Ravi P.; Singh, Jagdev
2018
Dynamical behaviors of a food-chain model with stage structure and time delays. Zbl 1446.37083
Huang, Chuangxia; Qiao, Yuncheng; Huang, Lihong; Agarwal, Ravi P.
2018
Nonlocal Hadamard fractional boundary value problem with Hadamard integral and discrete boundary conditions on a half-line. Zbl 06892266
Wang, Guotao; Pei, Ke; Agarwal, Ravi P.; Zhang, Lihong; Ahmad, Bashir
2018
A survey on fuzzy fractional differential and optimal control nonlocal evolution equations. Zbl 1388.34005
Agarwal, Ravi P.; Baleanu, Dumitru; Nieto, Juan J.; Torres, Delfim F. M.; Zhou, Yong
2018
Interpolative Reich-Rus-Ćirić type contractions on partial metric spaces. Zbl 06994859
Karapinar, Erdal; Agarwal, Ravi; Aydi, Hassen
2018
Some comments and notes on almost periodic functions and changing-periodic time scales. Zbl 1371.26044
Agarwal, Ravi P.; O’Regan, Donal
2018
Existence and concentration of positive ground state solutions for nonlinear fractional Schrödinger-Poisson system with critical growth. Zbl 1405.35252
Teng, Kaimin; Agarwal, Ravi P.
2018
Almost periodic oscillations for delay impulsive stochastic Nicholson’s blowflies timescale model. Zbl 1405.34067
Wang, Chao; Agarwal, Ravi P.; Rathinasamy, Sakthivel
2018
Numerical solution for system of Cauchy type singular integral equations with its error analysis in complex plane. Zbl 1427.65427
Sharma, Vaishali; Setia, Amit; Agarwal, Ravi P.
2018
Some stability properties related to initial time difference for Caputo fractional differential equations. Zbl 1393.34011
Agarwal, Ravi; Hristova, Snezhana; O’Regan, Donal
2018
Some new nonlinear second-order boundary value problems on an arbitrary domain. Zbl 1446.34032
Alsaedi, Ahmed; Alsulami, Mona; Agarwal, Ravi P.; Ahmad, Bashir
2018
Caristi type cyclic contraction and common fixed point theorems in bipolar metric spaces with applications. Zbl 06968542
Kishore, G. N. V.; Agarwal, Ravi P.; Srinuvasa Rao, B.; Srinivasa Rao, R. V. N.
2018
$$n_0$$-order $$\Delta$$-almost periodic functions and dynamic equations. Zbl 1402.26017
Wang, Chao; Agarwal, Ravi P.; O’Regan, Donal
2018
Asymptotic behavior, attracting and quasi-invariant sets for impulsive neutral SPFDE driven by Lévy noise. Zbl 1386.35019
Huan, Diem Dang; Agarwal, Ravi P.
2018
Positive solutions for a system of second-order discrete boundary value problems. Zbl 1448.39017
Agarwal, Ravi P.; Luca, Rodica
2018
A switched multicontroller for an SEIADR epidemic model with monitored equilibrium points and supervised transients and vaccination costs. Zbl 1451.92282
de la Sen, M.; Agarwal, R. P.; Nistal, R.; Alonso-Quesada, S.; Ibeas, A.
2018
Existence theory for fractional differential equations with non-separated type nonlocal multi-point and multi-strip boundary conditions. Zbl 1445.34008
Ahmad, Bashir; Ntouyas, Sotiris K.; Alsaedi, Ahmed; Shammakh, Wafa; Agarwal, Ravi P.
2018
Threshold dynamics and optimal control of an age-structured giving up smoking model. Zbl 1392.92045
ur Rahman, Ghaus; Agarwal, Ravi P.; Liu, Lili; Khan, Asaf
2018
Iterative techniques for the initial value problem for Caputo fractional differential equations with non-instantaneous impulses. Zbl 1427.34027
Agarwal, Ravi; Hristova, S.; O’Regan, D.
2018
Existence and controllability for nonlinear fractional differential inclusions with nonlocal boundary conditions and time-varying delay. Zbl 1420.93008
Cheng, Yi; Agarwal, Ravi P.; O’Regan, Donal
2018
On De La Vallée Poussin-type inequalities in higher dimension and applications. Zbl 1407.35035
Agarwal, Ravi P.; Jleli, Mohamed; Samet, Bessem
2018
On sequential fractional integro-differential equations with nonlocal integral boundary conditions. Zbl 07008700
Ahmad, Bashir; Alsaedi, Ahmed; Agarwal, Ravi P.; Alsharif, Alaa
2018
A comparative study on generating function relations for generalized hypergeometric functions via generalized fractional operators. Zbl 1446.33004
Çetinkaya, Ayşegül; Kıymaz, İ. Onur; Agarwal, Praveen; Agarwal, Ravi
2018
Intersection theorems with applications in optimization. Zbl 1440.47045
Agarwal, Ravi P.; Balaj, Mircea; O’Regan, Donal
2018
A study of nonlocal integro-multi-point boundary value problems of sequential fractional integro-differential inclusions. Zbl 1395.45012
Ahmad, Bashir; Ntouyas, Sotiris K.; Alsaedi, Ahmed; Agarwal, Ravi P.
2018
Global attractivity for Volterra type Hadamard fractional integral equations in Fréchet spaces. Zbl 1393.45003
Abbas, Saïd; Agarwal, Ravi P.; Benchohra, Mouffak; Berhoun, Farida
2018
Multi-term fractional-order boundary-value problems with nonlocal integral boundary conditions. Zbl 1387.34003
Alsaedi, Ahmed; Alghamdi, Najla; Agarwal, Ravi P.; Ntouyas, Sotiris K.; Ahmad, Bashir
2018
Inequalities of Hardy type and generalizations on time scales. Zbl 1384.26046
Saker, Samir H.; Osman, Mahmoud M.; O’Regan, Donal; Agarwal, Ravi P.
2018
$$N$$ fixed point theorems and $$N$$ best proximity point theorems for generalized contraction in partially ordered metric spaces. Zbl 06858710
Zhang, Jingling; Agarwal, Ravi P.; Jiang, Nan
2018
Stability by Lyapunov like functions of nonlinear differential equations with non-instantaneous impulses. Zbl 1361.34064
Agarwal, Ravi; O’Regan, D.; Hristova, S.
2017
Existence results for coupled nonlinear fractional differential equations equipped with nonlocal coupled flux and multi-point boundary conditions. Zbl 1374.34060
Agarwal, Ravi P.; Ahmad, Bashir; Garout, Doa’a; Alsaedi, Ahmed
2017
Almost periodic solution for a new type of neutral impulsive stochastic Lasota-Wazewska timescale model. Zbl 1401.34099
Wang, Chao; Agarwal, Ravi P.
2017
Non-instantaneous impulses in Caputo fractional differential equations. Zbl 1370.34008
Agarwal, Ravi; Hristova, Snezhana; O’Regan, Donal
2017
Sums of finite products of Bernoulli functions. Zbl 1422.11037
Agarwal, Ravi P.; Kim, Dae San; Kim, Taekyun; Kwon, Jongkyum
2017
Noninstantaneous impulses in Caputo fractional differential equations and practical stability via Lyapunov functions. Zbl 1364.93551
Agarwal, Ravi; Hristova, S.; O’Regan, D.
2017
Non-instantaneous impulses in differential equations. Zbl 1426.34001
Agarwal, Ravi; Hristova, Snezhana; O’Regan, Donal
2017
Lyapunov type inequalities for mixed nonlinear Riemann-Liouville fractional differential equations with a forcing term. Zbl 1357.34009
Agarwal, Ravi P.; Özbekler, Abdullah
2017
Monotone iterative technique for the initial value problem for differential equations with non-instantaneous impulses. Zbl 1411.34031
Agarwal, Ravi; O’Regan, D.; Hristova, S.
2017
Fractional-order differential equations with anti-periodic boundary conditions: a survey. Zbl 1386.34007
Agarwal, Ravi P.; Ahmad, Bashir; Alsaedi, Ahmed
2017
A study of fractional-order coupled systems with a new concept of coupled non-separated boundary conditions. Zbl 1382.34005
Alsulami, Hamed H.; Ntouyas, Sotiris K.; Agarwal, Ravi P.; Ahmad, Bashir; Alsaedi, Ahmed
2017
Fixed point theorems in partially ordered Banach spaces with applications to nonlinear fractional evolution equations. Zbl 1398.35281
Yang, He; Agarwal, Ravi P.; Nashine, Hemant K.; Liang, Yue
2017
Stability with initial time difference of Caputo fractional differential equations by Lyapunov functions. Zbl 1365.34008
Agarwal, Ravi; O’Regan, Donal; Hristova, Snezhana
2017
Infinitely many periodic solutions for a class of new superquadratic second-order Hamiltonian systems. Zbl 1351.37233
Li, Chun; Agarwal, Ravi P.; Paşca, Daniel
2017
Some identities involving $$q$$-poly-tangent numbers and polynomials and distribution of their zeros. Zbl 1422.11054
Ryoo, C. S.; Agarwal, R. P.
2017
Montone-iterative techniques for mild solutions of the initial value problem Caputo fractional differential equations with non-instantaneous impulses. Zbl 1386.34023
Agarwal, Ravi; O’Regan, Donal; Hristova, Snezhana
2017
A note on Ćirić type nonunique fixed point theorems. Zbl 1382.54025
Karapınar, Erdal; Agarwal, Ravi P.
2017
Approximation of the multiplicatives on random multi-normed space. Zbl 1379.39002
Agarwal, Ravi P.; Saadati, Reza; Salamati, Ali
2017
Some new generalized forms of Hardy’s type inequality on time scales. Zbl 1367.26048
Saker, S. H.; Mahmoud, R. R.; Osman, M. M.; Agarwal, R. P.
2017
Fractional semilinear equations with causal operators. Zbl 1358.34087
Agarwal, Ravi P.; Asma; Lupulescu, Vasile; O’Regan, Donal
2017
On nonlinear fractional-order boundary value problems with nonlocal multi-point conditions involving Liouville-Caputo derivative. Zbl 1390.34014
Agarwal, Ravi P.; Alsaedi, Ahmed; Alsharif, Alaa; Ahmad, Bashir
2017
New Hilbert dynamic inequalities on time scales. Zbl 1386.26035
Saker, S. H.; Ahmed, A. M.; Rezk, H. M.; O’Regan, D.; Agarwal, R. P.
2017
P-moment exponential stability of Caputo fractional differential equations with noninstantaneous random impulses. Zbl 1378.34005
Agarwal, Ravi; Hristova, Snezhana; O’Regan, Donal
2017
A variety of inverse Hilbert type inequalities on time scales. Zbl 1372.34038
Saker, S. H.; Rezk, H. M.; O’Regan, D.; Agarwal, R. P.
2017
New generalizations of Popoviciu-type inequalities via new Green’s functions and Montgomery identity. Zbl 1362.26023
Mehmood, Nasir; Agarwal, Ravi P.; Butt, Saad Ihsan; Pečarić, Josip
2017
Weighted piecewise pseudo double-almost periodic solution for impulsive evolution equations. Zbl 1412.34246
Wang, Chao; Agarwal, Ravi P.; O’Regan, Donal
2017
Analytic solution of generalized space time fractional reaction diffusion equation. Zbl 1424.35334
Agarwal, Ritu; Jain, Sonal; Agarwal, R. P.
2017
New generalizations of Németh-Mohapatra type inequalities on time scales. Zbl 1399.26040
Agarwal, R. P.; Mahmoud, R. R.; Saker, S. H.; Tunç, C.
2017
Controllability for a class of integro-differential evolution equations involving non-local initial conditions. Zbl 1380.93063
Yang, He; Agarwal, Ravi P.; Liang, Yue
2017
Exact controllability of fractional integro-differential systems of order $$\alpha \in (1, 2]$$ with deviated argument. Zbl 1389.34239
Muslim, M.; Kumar, Avadhesh; Agarwal, Ravi P.
2017
Some fixed point theorems for almost $$(\mathrm{GF}, \delta_b)$$-contractions and application. Zbl 1369.54043
Nashine, H. K.; Agarwal, R. P.; Shukla, S.; Gupta, A.
2017
$$L^p$$-solutions for a class of fractional integral equations. Zbl 1370.45007
Agarwal, Ravi P.; Asma; Lupulescu, Vasile; O’Regan, Donal
2017
Common fixed point theorems in topological vector spaces via intersection theorems. Zbl 1453.47005
Agarwal, Ravi P.; Balaj, Mircea; O’Regan, Donal
2017
A mathematical model for three-phase-lag dipolar thermoelastic bodies. Zbl 1368.35261
Marin, M.; Agarwal, R. P.; Codarcea, L.
2017
Strict stability with respect to initial time difference for Caputo fractional differential equations by Lyapunov functions. Zbl 1362.34009
Agarwal, Ravi P.; O’Regan, Donal; Hristova, Snezhana
2017
Practical stability with respect to initial time difference for Caputo fractional differential equations. Zbl 07257078
Agarwal, Ravi; O’Regan, Donal; Hristova, S.; Cicek, M.
2017
Nonlinear fractional equations with supercritical growth. Zbl 1416.35297
Li, Lin; Agarwal, Ravi P.; Li, Chun
2017
Existence of fixed points for $$\gamma$$-$$FG$$-contractive condition via cyclic $$(\alpha,\beta)$$-admissible mappings in $$b$$-metric spaces. Zbl 1412.47072
Padhan, Saroj Kumar; Rao, G. V. V. Jagannadha; Al-Rawashdeh, Ahmed; Nashine, Hemant Kumar; Agarwal, Ravi P.
2017
A matched space for time scales and applications to the study on functions. Zbl 1422.26014
Wang, Chao; Agarwal, Ravi P.; O’Regan, Donal
2017
Coupled fixed point theorems with applications to fractional evolution equations. Zbl 1422.34073
Yang, He; Agarwal, Ravi P.; Nashine, Hemant K.
2017
Oscillation criteria for third-order functional half-linear dynamic equations. Zbl 1422.34258
Hassan, Taher S.; Agarwal, Ravi P.; Mohammed, Wael W.
2017
Practical stability of differential equations with non-instantaneous impulses. Zbl 1400.34089
Agarwal, Ravi; Hristova, Snezhana; O’Regan, Donal
2017
Impulsive differential equations with Gamma distributed moments of impulses and $$p$$-moment exponential stability. Zbl 1399.34043
Agarwal, R.; Hristova, S.; Kopanov, P.; O’Regan, D.
2017
Infinitely many solutions for a class of quasilinear equation with a combination of convex and concave terms. Zbl 1387.35315
Teng, Kaimin; Agarwal, Ravi P.
2017
$$p$$-moment exponential stability of differential equations with random impulses and the Erlang distribution. Zbl 1384.34069
Agarwal, R. P.; Hristova, S.; O’Regan, D.; Kopanov, P.
2017
Positive solutions of fractional integral equations by the technique of measure of noncompactness. Zbl 1421.45003
Nashine, Hemant Kumar; Arab, Reza; Agarwal, Ravi P.; de la Sen, Manuel
2017
...and 1214 more Documents
all top 5
Cited by 7,805 Authors
647 Agarwal, Ravi P. 370 O’Regan, Donal 135 Ahmad, Bashir 123 Ntouyas, Sotiris K. 123 Wong, Patricia J. Y. 117 Băleanu, Dumitru I. 110 Ge, Weigao 84 Li, Tongxing 81 Li, Wan-Tong 80 Zhou, Yong 77 Grace, Said Rezk 76 Saker, Samir H. 75 Al-saedi, Ahmed Eid Salem 73 Nieto Roig, Juan Jose 70 de la Sen, Manuel 69 Bohner, Martin J. 69 Graef, John R. 65 Liu, Lishan 63 Kang, Shin Min 62 Henderson, Johnny Lee 61 Karapınar, Erdal 61 Liu, Yuji 60 Samet, Bessem 58 Ma, Ruyun 55 Cho, Yeol Je 55 Hussain, Nawab 55 Sun, Shurong 55 Thandapani, Ethiraju 54 Wang, Jinrong 52 Benchohra, Mouffak 51 Han, Zhenlai 51 Jiang, Daqing 51 Tariboon, Jessada 48 Diblík, Josef 47 Kumam, Poom 47 Pečarić, Josip 43 Shi, Haiping 43 Wang, Guotao 43 Zhang, Binggen 40 Meng, Fanwei 40 Tang, Xianhua 40 Wu, Yonghong 39 Cuevas, Claudio 39 Liu, Zeqing 38 Gupta, Vijay 37 Li, Yongkun 37 Staněk, Svatoslav 36 Dragomir, Sever Silvestru 36 Khristova, Snezhana G. 36 Kong, Lingju 36 Liu, Wenbin 36 Zhang, Chenghui 35 Džurina, Jozef 35 Radenovic, Stojan 35 Zafer, Ağacık 34 Wang, Qiru 33 Abbas, Mujahid 33 Bai, Zhanbing 33 Nashine, Hemant Kumar 33 Rimas, Jonas 33 Wang, Yuanming 33 Zhou, Zhan 32 Ashyralyev, Allaberen 32 Cui, Yujun 32 Kiliçman, Adem 32 Torres, Delfim Fernando Marado 32 Wang, Wusheng 32 Zhang, Lihong 31 Brzdęk, Janusz 31 Cabada, Alberto 31 Došlá, Zuzana 30 Abdeljawad, Thabet 30 Feng, Meiqiang 30 Li, Yongxiang 30 Shakhmurov, Veli B. 29 Baculíková, Blanka 29 Chen, Haibo 29 Liu, Xia 29 Wong, Fu-Hsiang 28 Aydi, Hassen 28 Sun, Jianping 28 Tian, Yu 28 Zhang, Xinguang 27 Lan, Hengyou 27 Rezapour, Shahram 27 Sadarangani, Kishin B. 27 Yu, Jian-She 26 Anderson, Douglas Robert 26 Erbe, Lynn Harry 26 Rachůnková, Irena 26 Sarikaya, Mehmet Zeki 26 Suantai, Suthep 26 Wang, Chao 26 Zhang, Xuemei 26 Zhang, Yuanbiao 25 Berezansky, Leonid M. 25 Kim, Taekyun 25 Noor, Muhammad Aslam 25 Peterson, Allan C. 25 Sun, Yuangong ...and 7,705 more Authors
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Cited in 525 Serials
772 Advances in Difference Equations 761 Applied Mathematics and Computation 633 Computers & Mathematics with Applications 548 Journal of Mathematical Analysis and Applications 468 Abstract and Applied Analysis 424 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 367 Applied Mathematics Letters 323 Fixed Point Theory and Applications 302 Boundary Value Problems 265 Journal of Inequalities and Applications 244 Journal of Computational and Applied Mathematics 224 Mathematical and Computer Modelling 182 Discrete Dynamics in Nature and Society 182 Journal of Applied Mathematics and Computing 166 Journal of Difference Equations and Applications 127 Journal of Function Spaces 101 Journal of Applied Mathematics 100 Journal of Nonlinear Science and Applications 95 Mediterranean Journal of Mathematics 85 Journal of Fixed Point Theory and Applications 81 Mathematical Problems in Engineering 78 Mathematical Methods in the Applied Sciences 72 Applicable Analysis 69 Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A: Matemáticas. RACSAM 68 Fractional Calculus & Applied Analysis 68 Communications in Nonlinear Science and Numerical Simulation 67 Nonlinear Analysis. Real World Applications 58 Rocky Mountain Journal of Mathematics 53 Bulletin of the Malaysian Mathematical Sciences Society. Second Series 44 Journal of the Franklin Institute 42 Results in Mathematics 41 Journal of Differential Equations 41 Acta Applicandae Mathematicae 40 Chaos, Solitons and Fractals 40 International Journal of Computer Mathematics 39 Journal of Optimization Theory and Applications 39 Journal of Applied Analysis and Computation 38 International Journal of Mathematics and Mathematical Sciences 38 Differential Equations and Dynamical Systems 35 International Journal of Differential Equations 33 Fuzzy Sets and Systems 32 Ukrainian Mathematical Journal 32 Mathematical Sciences 31 Acta Mathematicae Applicatae Sinica. English Series 31 Journal of Mathematics 30 Nonlinear Dynamics 29 Numerical Functional Analysis and Optimization 29 Numerical Algorithms 29 Open Mathematics 28 Demonstratio Mathematica 28 Positivity 27 Proceedings of the American Mathematical Society 27 Nonlinear Analysis. Theory, Methods & Applications 26 Journal of Integral Equations and Applications 26 Symmetry 26 Fractional Differential Calculus 24 Rendiconti del Circolo Matemàtico di Palermo. Serie II 24 Applied Numerical Mathematics 24 Journal of Mathematical Sciences (New York) 24 Journal of the Egyptian Mathematical Society 23 Bulletin of the Australian Mathematical Society 23 Computational and Applied Mathematics 23 Nonlinear Analysis. Modelling and Control 23 Journal of Function Spaces and Applications 23 International Journal of Biomathematics 22 Czechoslovak Mathematical Journal 22 Mathematics and Computers in Simulation 22 Mathematische Nachrichten 22 Zeitschrift für Analysis und ihre Anwendungen 22 Turkish Journal of Mathematics 22 Opuscula Mathematica 22 Acta Mathematica Sinica. English Series 22 Nonlinear Analysis. Hybrid Systems 22 Afrika Matematika 22 Mathematics 21 Georgian Mathematical Journal 21 International Journal of Nonlinear Sciences and Numerical Simulation 20 Advances in Mathematical Physics 20 International Journal of Applied and Computational Mathematics 19 Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica 19 Differential Equations and Applications 18 Proceedings of the Indian Academy of Sciences. Mathematical Sciences 18 Differential Equations 18 Arabian Journal of Mathematics 17 Mathematica Slovaca 17 Vietnam Journal of Mathematics 17 Discrete and Continuous Dynamical Systems. Series B 17 Journal of Mathematical Inequalities 17 Tbilisi Mathematical Journal 16 Monatshefte für Mathematik 16 Applications of Mathematics 16 Electronic Journal of Differential Equations (EJDE) 16 Complexity 16 Asian-European Journal of Mathematics 15 Journal of Applied Analysis 15 Dynamics of Continuous, Discrete & Impulsive Systems. Series A. Mathematical Analysis 15 Complex Analysis and Operator Theory 14 Applied Mathematical Modelling 14 Linear Algebra and its Applications 14 Soft Computing ...and 425 more Serials
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Cited in 62 Fields
5,204 Ordinary differential equations (34-XX) 2,347 Operator theory (47-XX) 1,967 Difference and functional equations (39-XX) 1,210 Real functions (26-XX) 920 Numerical analysis (65-XX) 785 Partial differential equations (35-XX) 647 General topology (54-XX) 555 Integral equations (45-XX) 437 Biology and other natural sciences (92-XX) 355 Calculus of variations and optimal control; optimization (49-XX) 353 Systems theory; control (93-XX) 304 Approximations and expansions (41-XX) 243 Dynamical systems and ergodic theory (37-XX) 238 Global analysis, analysis on manifolds (58-XX) 174 Operations research, mathematical programming (90-XX) 167 Special functions (33-XX) 167 Functional analysis (46-XX) 142 Probability theory and stochastic processes (60-XX) 80 Number theory (11-XX) 78 Mechanics of deformable solids (74-XX) 77 Functions of a complex variable (30-XX) 54 Harmonic analysis on Euclidean spaces (42-XX) 54 Abstract harmonic analysis (43-XX) 52 Integral transforms, operational calculus (44-XX) 51 Combinatorics (05-XX) 50 Mechanics of particles and systems (70-XX) 49 Fluid mechanics (76-XX) 49 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 48 Linear and multilinear algebra; matrix theory (15-XX) 46 Measure and integration (28-XX) 30 Computer science (68-XX) 26 Sequences, series, summability (40-XX) 22 Statistics (62-XX) 22 Quantum theory (81-XX) 21 Information and communication theory, circuits (94-XX) 20 Potential theory (31-XX) 19 Convex and discrete geometry (52-XX) 18 Algebraic topology (55-XX) 18 Statistical mechanics, structure of matter (82-XX) 14 Classical thermodynamics, heat transfer (80-XX) 13 Order, lattices, ordered algebraic structures (06-XX) 13 Differential geometry (53-XX) 10 Manifolds and cell complexes (57-XX) 8 General and overarching topics; collections (00-XX) 8 Mathematical logic and foundations (03-XX) 7 History and biography (01-XX) 7 Optics, electromagnetic theory (78-XX) 5 Associative rings and algebras (16-XX) 5 Geophysics (86-XX) 4 Several complex variables and analytic spaces (32-XX) 4 Geometry (51-XX) 4 Relativity and gravitational theory (83-XX) 3 Field theory and polynomials (12-XX) 3 Algebraic geometry (14-XX) 3 Group theory and generalizations (20-XX) 2 Commutative algebra (13-XX) 2 Astronomy and astrophysics (85-XX) 1 General algebraic systems (08-XX) 1 Nonassociative rings and algebras (17-XX) 1 Category theory; homological algebra (18-XX) 1 Topological groups, Lie groups (22-XX) 1 Mathematics education (97-XX)
Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2021-05-13T18:40:43 |
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https://freespeech.fandom.com/wiki/Propagation_constant
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## FANDOM
2,220 Pages
The propagation constant of an electromagnetic wave is a measure of the change undergone by the amplitude of the wave as it propagates in a given direction. The quantity being measured can be the voltage or current in a circuit or a field vector such as electric field strength or flux density. The propagation constant itself measures change per metre but is otherwise dimensionless.
The propagation constant is expressed logarithmically, almost universally to the base e, rather than the more usual base 10 used in telecommunications in other situations. The quantity measured, such as voltage, is expressed as a sinusiodal phasor. The phase of the sinusoid varies with distance which results in the propagation constant being a complex number, the imaginary part being caused by the phase change.
### Alternative namesEdit
The term propagation constant is somewhat of a misnomer as it usually varies strongly with ω. It is probably the most widely used term but there are a large variety of alternative names used by various authors for this quantity. These include, transmission parameter, transmission function, propagation parameter, propagation coefficient and transmission constant. In plural, it is usually implied that α and β are being referenced separately but collectively as in transmission parameters, propagation parameters, propagation coefficients, transmission constants and secondary coefficients. This last occurs in transmission line theory, the term secondary being used to contrast to the primary line coefficients. The primary coefficients being the physical properties of the line; R,C,L and G, from which the secondary coefficients may be derived using the telegrapher's equation. Note that, at least in the field of transmission lines, the term transmission coefficient has a different meaning despite the similarity of name. Here it is the corollary of reflection coefficient.
### DefinitionEdit
The propagation constant, symbol γ, for a given system is defined by the ratio of the amplitude at the source of the wave to the amplitude at some distance x, such that,
$\frac{A_0}{A_x}=e^{\gamma x}$
Since the propagation constant, is a complex quantity we can write;
$\gamma = \alpha +i \beta \,$
where
α, the real part, is called the attenuation constant
β, the imaginary part, is called the phase constant
That β does indeed represent phase can be seen from Euler's formula;
$e^{i\theta}=\cos{\theta}+i\sin{\theta}\,\!$
which is a sinusoid which varies in phase as θ varies but does not vary in amplitude because;
$\left|e^{i\theta}\right|=\sqrt{\cos^2{\theta}+\sin^2{\theta}}=1$
The reason for the use of base e is also now made clear. The imaginary phase constant, iβ, can be added directly to the attenuation constant, α, to form a single complex number that can be handled in one mathematical operation provided they are to the same base. Angles measured in radians require base e, so the attenuation is likewise in base e.
For a copper transmission line, the propagation constant can be calcualted from the primary line coefficients by means of the relationship;
$\gamma=\sqrt{ZY}$
where;
$Z=R+i\omega L\,\!$, the series impedance of the line per metre and,
$Y=G+i\omega C\,\!$, the shunt admittance of the line per metre.
## Attenuation constantEdit
In telecommunications, the term attenuation constant, also called attenuation parameter or coefficient, is the attenuation of an electromagnetic wave propagating through a medium per unit distance from the source. It is the real part of the propagation constant and is measured in nepers per metre. A neper is approximately 8.7dB. Attenuation constant can be defined by the amplitude ratio;
$\left|\frac{A_0}{A_x}\right|=e^{\alpha}$
### Copper linesEdit
The attenuation constant can be calculated from the primary line coefficients as shown above. For a line meeting the distortionless condition, the attenuation constant is given by;
$\alpha=\sqrt{RG}\,\!$
however, a real line is unlikely to meet this condition without the addition of loading coils and, furthermore, there are some decidedly non-linear effects operation on the primary "constants" which cause a frequency dependence of the loss. There are two main components to these losses, the metal loss and the dielectric loss.
The loss of most transmission lines are dominated by the metal loss, which causes a frequency dependency due to finite conductivity of metals, and the skin effect. The skin effect causes R to be approximately dependent on frequency according to;
$R \propto \sqrt{\omega}$
Losses in the dielectric depend on the loss tangent (${tan \delta}$) of the material, which depends inversely on the wavelength of the signal and is directly proportional to the frequency.
$\alpha_d={{\pi}\sqrt{\varepsilon_r}\over{\lambda}}{\tan \delta}$
### Optical fibreEdit
The attenuation constant for a particular propagation mode in an optical fiber, the real part of the axial propagation constant.
## Phase constantEdit
In electromagnetic theory, the phase constant, also called phase change constant, parameter or coefficient is the imaginary component of the propagation constant for a plane wave. It represents the change in phase per metre along the path travelled by the wave at any instant and is equal to the angular wavenumber (often incorrectly abbreviated to wavenumber) of the wave. It is represented by the symbol β and is measured in units of radians per metre.
From the definition of angular wavenumber;
$k = \frac{2\pi}{\lambda} = \beta$
For a transmission line, the Heaviside condition of the telegrapher's equation tells us that the wavenumber must be proportional to frequency for the transmission of the wave to be undistorted in the time domain. This includes, but is not limited to, the ideal case of a lossless line. The reason for this condition can be seen by considering that a useful signal is composed of many different wavelengths in the frequency domain. For there to be no distortion of the waveform, all these waves must travel at the same velocity so that they arrive at the far end of the line at the same time as a group. Since wave phase velocity is given by;
$v_p=\frac{\lambda}{T}=\frac{f}{\tilde{\nu}}=\frac{\omega}{\beta}$
it is proved that β is required to be proportional to ω. In terms of primary coefficients of the line, this yields from the telegrapher's equation for a distortionless line the condition;
$\beta = \omega \sqrt{LC}$
However, practical lines can only be expected to approximately meet this condition over a limited frequency band.
## FiltersEdit
The term propagation constant or propagation function is applied to filters and other two-port networks used for signal processing. In these cases, however, the attenuation and phase coefficients are expressed in terms of nepers and radians per network section rather than per metre. Some authors[1] make a distinction between per metre measures (for which "constant" is used) and per section measures (for which "function" is used).
The propagation constant is a useful concept in filter design which invariably uses a cascaded section topology. In a cascaded topology, the propagation constant, attenuation constant and phase constant of individual sections may be simply added to find the total propagation constant etc.
As input and output impedences are equal under zo termination ie, zo termination = V1/I1 = V2/(-I2)
V1/V2 = I1/I2 = eγ
For 'n' number of sections cascaded' with all of them having the same zo value' the ratio of currents can be written as
(I 1/ -I 2) × (-I 2 / -I 3) × ..... × (-I n-1 / -I n) = (I 1 / -I n)
=> eγ1 × eγ2 × ... × = eγ
The over all propagation constant γ = γ12+....+γn
## ReferencesEdit
Template:Sci-stub
Cite error: <ref> tags exist, but no <references/> tag was found
Community content is available under CC-BY-SA unless otherwise noted.
| 2019-06-26T19:53:51 |
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https://pdglive.lbl.gov/DataBlock.action?node=M144W&home=sumtabM
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${{\boldsymbol h}_{{c}}{(1P)}}$ WIDTH INSPIRE search
VALUE (MeV) CL% EVTS DOCUMENT ID TECN COMMENT
$0.70$ $\pm0.28$ $\pm0.22$ 832 1
2012 N
BES3 ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \pi}^{0}}{{\mathit \gamma}}$ hadrons
• • • We do not use the following data for averages, fits, limits, etc. • • •
$\text{< 1.44}$ 90 3679 2
2010 B
BES3 ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \pi}^{0}}{{\mathit \gamma}}{{\mathit \eta}_{{c}}}$
$\text{< 1}$ 13
2005 B
E835 ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \eta}_{{c}}}{{\mathit \gamma}}$
$\text{< 1.1}$ 90 59
1992 D
E760 ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{0}}$
1 With floating mass.
2 The central value is = $0.73$ $\pm0.45$ $\pm0.28$ MeV.
References:
ABLIKIM 2012N
PR D86 092009 Study of ${{\mathit \psi}{(3686)}}$ $\rightarrow$ ${{\mathit \pi}^{0}}{{\mathit h}_{{c}}}$ , ${{\mathit h}_{{c}}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{c}}}$ via ${{\mathit \eta}_{{c}}}$ Exclusive Decays
ABLIKIM 2010B
PRL 104 132002 Measurements of ${{\mathit h}_{{c}}}({}^{1}\!{\mathit P}_{1}$) in ${{\mathit \psi}^{\,'}}$ Decays
ANDREOTTI 2005B
PR D72 032001 Results of a Search for the ${{\mathit h}_{{c}}}({}^{1}{{\mathit P}_{{1}}}$) State of Charmonium in the ${{\mathit \eta}_{{c}}}{{\mathit \gamma}}$ and ${{\mathit J / \psi}}{{\mathit \pi}^{0}}$ Decay Modes
ARMSTRONG 1992D
PRL 69 2337 Observation of the ${}^{1}\mathit P_{1}$ State of Charmonium
| 2021-02-28T22:20:55 |
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http://pdglive.lbl.gov/DataBlock.action;jsessionid=129811C238B86292D30244E7919E6E18?node=S046OTH&init=0
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# Supersymmetry miscellaneous results INSPIRE search
Results that do not appear under other headings or that make nonminimal assumptions.
Some earlier papers are now obsolete and have been omitted. They were last listed in our PDG 2014 edition: K. Olive, $\mathit et~al.$ (Particle Data Group), Chinese Physics C38 070001 (2014) (http://pdg.lbl.gov).
VALUE CL% DOCUMENT ID TECN COMMENT
• • • We do not use the following data for averages, fits, limits, etc. • • •
$> 65$ 95 1
2016 AF
ATLS selected ATLAS searches on EWK sector
$\text{ none 0 - 2}$ 95 2
2016 AG
ATLS dark photon, ${{\mathit \gamma}_{{d}}}$, in SUSY- and Higgs-portal models
3
2013 P
ATLS dark ${{\mathit \gamma}}$, hidden valley
4
2012 AB
CDF hidden-valley Higgs
$\text{none 100 - 185}$ 95 5
2011 AA
ATLS scalar gluons
6
2011 E
CMS ${{\mathit \mu}}{{\mathit \mu}}$ resonances
7
2010 N
D0 ${{\mathit \gamma}_{{D}}}$, hidden valley
1 AABOUD 2016AF uses a selection of searches by ATLAS for the electroweak production of SUSY particles studying resulting constraints on dark matter candidates. They use 20 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV. A likelihood-driven scan of an effective model focusing on the gaugino-higgsino and Higgs sector of the pMSSM is performed. The ATLAS searches impact models where ${\mathit m}_{{{\mathit \chi}_{{1}}^{0}}}$ $<$ 65 GeV, excluding 86$\%$ of them. See their Figs. 2, 4, and 6.
2 AAD 2016AG searches for prompt lepton-jets using 20 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV collected with the ATLAS detector. Lepton-jets are expected from decays of low-mass dark photons in SUSY-portal and Higgs-portal models. No significant excess of events is observed and 95$\%$ CL upper limits are computed on the production cross section times branching ratio for two prompt lepton-jets in models predicting 2 or 4 ${{\mathit \gamma}_{{d}}}$ via SUSY-portal topologies, for ${{\mathit \gamma}_{{d}}}$ mass values between 0 and 2 GeV. See their Figs 9 and 10. The results are also interpreted in terms of a 90$\%$ CL exclusion region in kinetic mixing and dark-photon mass parameter space. See their Fig. 13.
3 AAD 2013P searched in 5 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for single lepton-jets with at least four muons; pairs of lepton-jets, each with two or more muons; and pairs of lepton-jets with two or more electrons. All of these could be signatures of Hidden Valley supersymmetric models. No statistically significant deviations from the Standard Model expectations are found. 95$\%$ C.L. limits are placed on the production cross section times branching ratio of dark photons for several parameter sets of a Hidden Valley model.
4 AALTONEN 2012AB looked in 5.1 fb${}^{-1}$ of ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV for anomalous production of multiple low-energy leptons in association with a ${{\mathit W}}$ or ${{\mathit Z}}$ boson. Such events may occur in hidden valley models in which a supersymmetric Higgs boson is produced in association with a ${{\mathit W}}$ or ${{\mathit Z}}$ boson, with ${{\mathit H}}$ $\rightarrow$ ${{\widetilde{\mathit \chi}}_{{1}}^{0}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ pair and with the ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ further decaying into a dark photon (${{\mathit \gamma}_{{D}}}$) and the unobservable lightest SUSY particle of the hidden sector. As the ${{\mathit \gamma}_{{D}}}$ is expected to be light, it may decay into a lepton pair. No significant excess over the SM expectation is observed and a limit at 95$\%$ C.L. is set on the cross section for a benchmark model of supersymmetric hidden-valley Higgs production.
5 AAD 2011AA looked in 34 pb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for events with ${}\geq{}$4 jets originating from pair production of scalar gluons, each decaying to two gluons. No two-jet resonances are observed over the SM background. Limits are derived on the cross section times branching ratio (see Fig. 3). Assuming 100$\%$ branching ratio for the decay to two gluons, the quoted exclusion range is obtained, except for a 5 GeV mass window around 140 GeV.
6 CHATRCHYAN 2011E looked in 35 pb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for events with collimated ${{\mathit \mu}}$ pairs (leptonic jets) from the decay of hidden sector states. No evidence for new resonance production is found. Limits are derived and compared to various SUSY models (see Fig. 4) where the LSP, either the ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ or a ${{\widetilde{\mathit q}}}$, decays to dark sector particles.
7 ABAZOV 2010N looked in 5.8 fb${}^{-1}$ of ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV for events from hidden valley models in which a ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ decays into a dark photon, ${{\mathit \gamma}_{{D}}}$, and the unobservable lightest SUSY particle of the hidden sector. As the ${{\mathit \gamma}_{{D}}}$ is expected to be light, it may decay into a tightly collimated lepton pair, called lepton jet. They searched for events with $\not E_T$ and two isolated lepton jets observable by an opposite charged lepton pair ${{\mathit e}}{{\mathit e}}$ , ${{\mathit e}}{{\mathit \mu}}$ or ${{\mathit \mu}}{{\mathit \mu}}$ . No significant excess over the SM expectation is observed, and a limit at 95$\%$ C.L. on the cross section times branching ratio is derived, see their Table I. They also examined the invariant mass of the lepton jets for a narrow resonance, see their Fig. 4, but found no evidence for a signal.
References:
AABOUD 2016AF
JHEP 1609 175 Dark Matter Interpretations of ATLAS Searches for the Electroweak Production of Supersymmetric Particles in $\sqrt {s }$ = 8 TeV Proton-Proton Collisions
JHEP 1602 062 A Search for Prompt Lepton-Jets in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
PL B719 299 A Search for Prompt Lepton-Jets in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 7 TeV with the ATLAS Detector
PR D85 092001 Search for Anomalous Production of Multiple Leptons in Association with ${{\mathit W}}$ and ${{\mathit Z}}$ Bosons at CDF
EPJ C71 1828 Search for Massive Colored Scalars in Four-Jet Final States in $\sqrt {s }$ = 7 TeV Proton$−$Proton Collisions with the ATLAS Detector
PRL 105 211802 Search for Events with Leptonic Jets and Missing Transverse Energy in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
| 2018-07-19T02:09:52 |
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|
http://dlmf.nist.gov/14.16
|
# §14.16 Zeros
## §14.16(i) Notation
Throughout this section we assume that $\mu$ and $\nu$ are real, and when they are not integers we write
14.16.1 $\displaystyle\mu$ $\displaystyle=m+\delta_{\mu},$ $\displaystyle\nu$ $\displaystyle=n+\delta_{\nu},$
where $m$, $n\in\Integer$ and $\delta_{\mu}$, $\delta_{\nu}\in(0,1)$. For all cases concerning $\mathop{\mathsf{P}^{\mu}_{\nu}\/}\nolimits\!\left(x\right)$ and $\mathop{P^{\mu}_{\nu}\/}\nolimits\!\left(x\right)$ we assume that $\nu\geq-\frac{1}{2}$ without loss of generality (see (14.9.5) and (14.9.11)).
## §14.16(ii) Interval $-1
The number of zeros of $\mathop{\mathsf{P}^{\mu}_{\nu}\/}\nolimits\!\left(x\right)$ in the interval $(-1,1)$ is $\max(\lceil\nu-|\mu|\rceil,0)$ if any of the following sets of conditions hold:
• (a)
$\mu\leq 0$.
• (b)
$\mu>0$, $n\geq m$, and $\delta_{\nu}>\delta_{\mu}$.
• (c)
$\mu>0$, $n, and $m-n$ is odd.
• (d)
$\nu=0,1,2,3,\dots$.
The number of zeros of $\mathop{\mathsf{P}^{\mu}_{\nu}\/}\nolimits\!\left(x\right)$ in the interval $(-1,1)$ is $\max(\lceil\nu-|\mu|\rceil,0)+1$ if either of the following sets of conditions holds:
• (a)
$\mu>0$, $n>m$, and $\delta_{\nu}\leq\delta_{\mu}$.
• (b)
$\mu>0$, $n, and $m-n$ is even.
The zeros of $\mathop{\mathsf{Q}^{\mu}_{\nu}\/}\nolimits\!\left(x\right)$ in the interval $(-1,1)$ interlace those of $\mathop{\mathsf{P}^{\mu}_{\nu}\/}\nolimits\!\left(x\right)$. $\mathop{\mathsf{Q}^{\mu}_{\nu}\/}\nolimits\!\left(x\right)$ has $\max(\lceil\nu-|\mu|\rceil,0)+k$ zeros in the interval $(-1,1)$, where $k$ can take one of the values $-1$, $0$, $1$, $2$, subject to $\max(\lceil\nu-|\mu|\rceil,0)+k$ being even or odd according as $\mathop{\cos\/}\nolimits\!\left(\nu\pi\right)$ and $\mathop{\cos\/}\nolimits\!\left(\mu\pi\right)$ have opposite signs or the same sign. In the special case $\mu=0$ and $\nu=n=0,1,2,3,\dots$, $\mathop{\mathsf{Q}_{n}\/}\nolimits\!\left(x\right)$ has $n+1$ zeros in the interval $-1.
For uniform asymptotic approximations for the zeros of $\mathop{\mathsf{P}^{-m}_{n}\/}\nolimits\!\left(x\right)$ in the interval $-1 when $n\to\infty$ with $m$ $(\geq 0)$ fixed, see Olver (1997b, p. 469).
## §14.16(iii) Interval $1
$\mathop{P^{\mu}_{\nu}\/}\nolimits\!\left(x\right)$ has exactly one zero in the interval $(1,\infty)$ if either of the following sets of conditions holds:
• (a)
$\mu>0$, $\mu>\nu$, $\mu\notin\Integer$, and $\mathop{\sin\/}\nolimits\!\left((\mu-\nu)\pi\right)$ and $\mathop{\sin\/}\nolimits\!\left(\mu\pi\right)$ have opposite signs.
• (b)
$\mu\leq\nu$, $\mu\notin\Integer$, and $\lfloor\mu\rfloor$ is odd.
For all other values of $\mu$ and $\nu$ (with $\nu\geq-\frac{1}{2}$) $\mathop{P^{\mu}_{\nu}\/}\nolimits\!\left(x\right)$ has no zeros in the interval $(1,\infty)$.
$\mathop{\boldsymbol{Q}^{\mu}_{\nu}\/}\nolimits\!\left(x\right)$ has no zeros in the interval $(1,\infty)$ when $\nu>-1$, and at most one zero in the interval $(1,\infty)$ when $\nu<-1$.
| 2016-10-22T11:39:22 |
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|
https://www.usgs.gov/center-news/volcano-watch-sputtering-lava-flows-build-behind-shield
|
# Volcano Watch — Sputtering lava flows build behind shield
Release Date:
The episode 51 vents on the west flank of Puu Oo which were inactive for six days starting Tuesday, April 28, were in continuous eruption since Monday, May 4, starting at about noon, until Friday afternoon. During this 18-day interval, the eruption was nearly constant in level of activity, as seen in tremor of nearly constant amplitude.
Sputtering lava flows build behind shield
(Public domain.)
The episode 51 vents on the west flank of Puu Oo which were inactive for six days starting Tuesday, April 28, were in continuous eruption since Monday, May 4, starting at about noon, until Friday afternoon. During this 18-day interval, the eruption was nearly constant in level of activity, as seen in tremor of nearly constant amplitude.
The tremor we measure near the vent is a low-frequency ground vibration related to the flow of lava through the vent. The vents are sealed over with spatter and the lava flows from the vent through a tube to the pond. Between about 1:30 and 2:00 p.m. on Friday, the tremor decreased gradually as the eruption at the episode 51 vent apparently waned and then stopped.
The only time during this eruptive interval that the lava volume fluctuated greatly occurred last Monday, when the eruption rate declined to less than one-half of what it was for about eight to nine hours. During this period of lower eruption rate, the pond adjacent to the episode 51 vents drained, and the lava from the vent cascaded down about 15 to 25 feet into the empty pond, across the pond floor, and exited through a lava tube towards the south. The flows have not advanced beyond the limits of earlier flows from episodes 50 and 51. Instead, the flows have been building up a low shield surrounding the pond. This shield was measured on May 14 and found to be between 130 and 150 feet higher than the surface that existed before episode 50 began on February 17.
When the eruption rate is higher, as it has been during most of this eruptive interval, the pond has been full and overflowing or nearly full, with the lava exiting the pond through a tube headed towards the south. This tube transports the lava down the south flank of the shield, where it surfaces within a second perched pond surrounded by two- to five-foot tall levees. This second perched pond is currently about 300 to 350 feet in diameter.
For a long time, the lava lake inside Puu Oo was at, or very near, the same elevation as the episode 51 eruptive vent. When the pond level rose, the eruption became more vigorous, and was characterized by low spattering and even occasional low-level fountains. When the pond level dropped, the eruption became less vigorous or stopped. This relation between eruptive activity and the level of the pond inside Puu Oo no longer appears valid. The pond inside Puu Oo is now located about 230 feet below the rim and well below the level of the episode 51 vent on the west flank of Puu Oo. The continuous character of the current eruptive interval is probably related to the changes that have disconnected the lava lake inside Puu Oo from the episode 51 vent.
During the last few days, the fume cloud from Puu Oo has been particularly dense; the increase in fume is caused by the low level of the lava lake inside Puu O`o. When the lava lake is higher, the lava in the lake blocks the escape of gas from underlying magma, with the result that the fume cloud is smaller. Some of the apparent difference is also that the light Kona winds have not blown the fume away from the vent as quickly as do the trade winds.
| 2019-12-15T02:53:16 |
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|
https://wa.nlcs.gov.bt/wp-content/uploads/2019/03/index5.php?yhsw=cosx-root
|
Cosx root
## Cosx root
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| 2020-08-08T23:04:56 |
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|
https://cmerwebmap.cr.usgs.gov/catalog/catalogParty/show?partyId=Douglas+A.+Burns
|
Soil represents the largest store of mercury (Hg) in terrestrial ecosystems, and further study of the factors associated with soil Hg storage is needed to address concerns about the magnitude and persistence of global environmental Hg bioaccumulation. To address this need, we compared total Hg and methyl Hg concentrations and stores in the soil of different landscapes in two watersheds in different geographic settings with similar and relatively high methyl Hg concentrations in surface waters and biota, Fishing Brook, Adirondack Mountains, New York, and McTier Creek, Coastal Plain, South Carolina. Median total Hg concentrations and stores in organic and mineral soil samples were three-fold greater at Fishing Brook... Categories: Publication; Types: Citation; Tags: PLoS ONE Categories: Publication; Types: Citation; Tags: Fact Sheet Forested headwater streams in the Catskill Mountains of New York show significant among-catchment variability in mean annual nitrate (NO3-) concentrations. Large contributions from deep groundwater with high NO3- concentrations have been invoked to explain high NO3- concentrations in stream water during the growing season. To determine whether variable contributions of groundwater could explain among-catchment differences in streamwater, we measured NO3- concentrations in 58 groundwater seeps distributed across six catchments known to have different annual average streamwater concentrations. Seeps were identified based on release from bedrock fractures and bedding planes and had consistently lower temperatures than... Categories: Publication; Types: Citation; Tags: Water, Air, & Soil Pollution Quantifying biogeochemical cycles of nitrogen (N) and the associated fluxes to surface waters remains challenging, given the need to deal with spatial and temporal variability and to characterize complex and heterogeneous landscapes. We focused our study on catchments S14 and S15 located in the Adirondack Mountains of New York, USA, which have similar topographic and hydrologic characteristics but contrasting stream nitrate ($\hbox{NO}_{3}^{-}$) concentrations. We characterized the mechanisms by which $\hbox{NO}_{3}^{-}$ reaches the streams during hydrological events in these catchments, aiming to reconcile our field data with our conceptual model of factors that regulate nutrient exports from forested catchments.... Categories: Publication; Types: Citation; Tags: Hydrological Processes This study evaluated the contribution of winter rain-on-snow (ROS) events to annual and seasonal nitrate (N-NO3) export and identified the regional meteorological drivers of inter-annual variability in ROS N-NO3 export (ROS-N) at 9 headwater streams located across Ontario, Canada and the northeastern United States. Although on average only 3.3 % of annual precipitation fell as ROS during winter over the study period, these events contributed a significant proportion of annual and winter N-NO3 export at the majority of sites (average of 12 and 42 %, respectively); with the exception of the most northern catchment, where total winter precipitation was exceptionally low (average 77 mm). In years with a greater magnitude... Categories: Publication; Types: Citation; Tags: Biogeochemistry
| 2023-02-07T19:21:19 |
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|
https://gea.esac.esa.int/archive/documentation/GDR2/Gaia_archive/chap_datamodel/sec_dm_main_tables/ssec_dm_gaia_source.html
|
# 14.1.1 gaia_source
This table has an entry for every Gaia observed source as listed in the Main Database accumulating catalogue version from which the catalogue release has been generated. It contains the basic source parameters, that is only final data (no epoch data) and no spectra (neither final nor epoch).
Columns description:
solution_id : Solution Identifier (long)
All Gaia data processed by the Data Processing and Analysis Consortium comes tagged with a solution identifier. This is a numeric field attached to each table row that can be used to unequivocally identify the version of all the subsystems that where used in the generation of the data as well as the input data used. It is mainly for internal DPAC use but is included in the published data releases to enable end users to examine the provenance of processed data products. To decode a given solution ID visit https://gaia.esac.esa.int/decoder/solnDecoder.jsp
designation : Unique source designation (unique across all Data Releases) (string)
A source designation, unique across all Gaia Data Releases, that is constructed from the prefix “Gaia DRx ” followed by a string of digits corresponding to source_id (3 space–separated words in total). Note that the integer source identifier source_id is not guaranteed to be unique across Data Releases; moreover it is not guaranteed that the same astronomical source will always have the same source_id in different Data Releases. Hence the only safe way to compare source records between different Data Releases in general is to check the records of proximal source(s) in the same small part of the sky.
source_id : Unique source identifier (unique within a particular Data Release) (long)
A unique numerical identifier of the source, encoding the approximate position of the source (roughly to the nearest arcmin), the provenance (data processing centre where it was created), a running number, and a component number.
The approximate equatorial (ICRS) position is encoded using the nested HEALPix scheme at level 12 (Nside = 4096), which divides the sky into $\simeq 200$ million pixels of about 0.7 arcmin${}^{2}$.
The source ID consists of a 64-bit integer, least significant bit = 1 and most significant bit = 64, comprising:
• a HEALPix index number (sky pixel) in bits 36 - 63; by definition the smallest HEALPix index number is zero.
• a 3-bit Data Processing Centre code in bits 33 - 35; for example MOD(source_id / 4294967296, 8) can be used to distinguish between sources initialised via the Initial Gaia Source List by the Torino DPC (code = 0) and sources otherwise detected and assigned by Gaia observations (code $>0$)
• a 25-bit plus 7 bit sequence number within the HEALPix pixel in bits 1 - 32 split into:
• a 25 bit running number in bits 8 - 32; the running numbers are defined to be positive, i.e. never zero
• a 7-bit component number in bits 1 - 7
This means that the HEALpix index level 12 of a given source is contained in the most significant bits. HEALpix index of 12 and lower levels can thus be retrieved as follows:
• HEALpix level 12 = source_id / 34359738368
• HEALpix level 11 = source_id / 137438953472
• HEALpix level 10 = source_id / 549755813888
• HEALpix level n = source_id / $2^{35}\times 4^{(12-{\rm level})}$
Additional details can be found in the Gaia DPAC public document Source Identifiers — Assignment and Usage throughout DPAC (document code GAIA–C3–TN–ARI–BAS–020) available from https://www.cosmos.esa.int/web/gaia/public-dpac-documents
random_index : Random index used to select subsets (long)
Random index which can be used to select smaller subsets of the data that are still representative. The column contains a random permutation of the numbers from 0 to N-1, where N is the number of sources in the table.
The random index can be useful for validation (testing on 10 different random subsets), visualization (displaying 1% of the data), and statistical exploration of the data, without the need to download all the data.
ref_epoch : Reference epoch (double, Time[Julian Years])
Reference epoch to which the astrometric source parameters are referred, expressed as a Julian Year in TCB.
At DR2 this reference epoch is always J2015.5 but in future releases this will be different and not necessarily the same for all sources.
ra : Right ascension (double, Angle[deg])
Barycentric right ascension $\alpha$ of the source in ICRS at the reference epoch ref_epoch
ra_error : Standard error of right ascension (double, Angle[mas])
Standard error $\sigma_{\alpha*}\equiv\sigma_{\alpha}\cos\delta$ of the right ascension of the source in ICRS at the reference epoch ref_epoch.
dec : Declination (double, Angle[deg])
Barycentric declination $\delta$ of the source in ICRS at the reference epoch ref_epoch
dec_error : Standard error of declination (double, Angle[mas])
Standard error $\sigma_{\delta}$ of the declination of the source in ICRS at the reference epoch ref_epoch
parallax : Parallax (double, Angle[mas] )
Absolute stellar parallax $\varpi$ of the source at the reference epoch ref_epoch
parallax_error : Standard error of parallax (double, Angle[mas] )
Standard error $\sigma_{\varpi}$ of the stellar parallax at the reference epoch ref_epoch
parallax_over_error : Parallax divided by its error (float)
Parallax divided by its standard error
pmra : Proper motion in right ascension direction (double, Angular Velocity[mas/year])
Proper motion in right ascension $\mu_{\alpha*}\equiv\mu_{\alpha}\cos\delta$ of the source in ICRS at the reference epoch ref_epoch. This is the local tangent plane projection of the proper motion vector in the direction of increasing right ascension.
pmra_error : Standard error of proper motion in right ascension direction (double, Angular Velocity[mas/year] )
Standard error $\sigma_{\mu\alpha*}$ of the local tangent plane projection of the proper motion vector in the direction of increasing right ascension at the reference epoch ref_epoch
pmdec : Proper motion in declination direction (double, Angular Velocity[mas/year] )
Proper motion in declination $\mu_{\delta}$ of the source at the reference epoch ref_epoch. This is the projection of the proper motion vector in the direction of increasing declination.
pmdec_error : Standard error of proper motion in declination direction (double, Angular Velocity[mas/year] )
Standard error $\sigma_{\mu\delta}$ of the proper motion component in declination at the reference epoch ref_epoch
ra_dec_corr : Correlation between right ascension and declination (float, Dimensionless[see description])
Correlation coefficient $\rho(\alpha,\delta)$ between right ascension and declination, a dimensionless quantity in the range [-1,+1]
ra_parallax_corr : Correlation between right ascension and parallax (float, Dimensionless[see description])
Correlation coefficient $\rho(\alpha,\varpi)$ between right ascension and parallax, a dimensionless quantity in the range [-1,+1]
ra_pmra_corr : Correlation between right ascension and proper motion in right ascension (float, Dimensionless[see description])
Correlation coefficient $\rho(\alpha,\mu_{\alpha*})$ between right ascension and proper motion in right ascension, a dimensionless quantity in the range [-1,+1]
ra_pmdec_corr : Correlation between right ascension and proper motion in declination (float, Dimensionless[see description])
Correlation coefficient $\rho(\alpha,\mu_{\delta})$ between right ascension and proper motion in declination, a dimensionless quantity in the range [-1,+1]
dec_parallax_corr : Correlation between declination and parallax (float, Dimensionless[see description])
Correlation coefficient $\rho(\delta,\varpi)$ between declination and parallax, a dimensionless quantity in the range [-1,+1]
dec_pmra_corr : Correlation between declination and proper motion in right ascension (float, Dimensionless[see description])
Correlation coefficient $\rho(\delta,\mu_{\alpha*})$ between declination and proper motion in right ascension, a dimensionless quantity in the range [-1,+1]
dec_pmdec_corr : Correlation between declination and proper motion in declination (float, Dimensionless[see description])
Correlation coefficient $\rho(\delta,\mu_{\delta})$ between declination and proper motion in declination, a dimensionless quantity in the range [-1,+1]
parallax_pmra_corr : Correlation between parallax and proper motion in right ascension (float, Dimensionless[see description])
Correlation coefficient $\rho(\varpi,\mu_{\alpha*})$ between parallax and proper motion in right ascension, a dimensionless quantity in the range [-1,+1]
parallax_pmdec_corr : Correlation between parallax and proper motion in declination (float, Dimensionless[see description])
Correlation coefficient $\rho(\varpi,\mu_{\delta})$ between parallax and proper motion in declination, a dimensionless quantity in the range [-1,+1]
pmra_pmdec_corr : Correlation between proper motion in right ascension and proper motion in declination (float, Dimensionless[see description])
Correlation coefficient $\rho(\mu_{\alpha*},\mu_{\delta})$ between proper motion in right ascension and proper motion in declination, a dimensionless quantity in the range [-1,+1]
astrometric_n_obs_al : Total number of observations AL (int)
Total number of AL observations (= CCD transits) used in the astrometric solution of the source, independent of their weight. Note that some observations may be strongly downweighted (see
astrometric_n_obs_ac : Total number of observations AC (int)
Total number of AC observations (= CCD transits) used in the astrometric solution of the source, independent of their weight. Nearly all sources having G $<13$ will have AC observations from 2d windows, while fainter than that limit only $\sim 1$% of transit observations (the so–called ‘calibration faint stars’) are assigned 2d windows resulting in AC observations.
astrometric_n_good_obs_al : Number of good observations AL (int)
Number of AL observations (= CCD transits) that were not strongly downweighted in the astrometric solution of the source. Strongly downweighted observations (with downweighting factor $w<0.2$) are instead counted in astrometric_n_bad_obs_al. The sum of astrometric_n_good_obs_al and astrometric_n_bad_obs_al equals
astrometric_n_obs_al, the total number of AL observations used in the astrometric solution of the source.
Number of AL observations (= CCD transits) that were strongly downweighted in the astrometric solution of the source, and therefore contributed little to the determination of the astrometric parameters. An observation is considered to be strongly downweighted if its downweighting factor $w<0.2$, which means that the absolute value of the astrometric residual exceeds 4.83 times the total uncertainty of the observation, calculated as the quadratic sum of the centroiding uncertainty, excess source noise, and excess attitude noise.
astrometric_gof_al : Goodness of fit statistic of model wrt along-scan observations (float)
Goodness-of-fit statistic of the astrometric solution for the source in the along-scan direction. This is the ‘gaussianized chi-square’, which for good fits should approximately follow a normal distribution with zero mean value and unit standard deviation. Values exceeding, say, $+3$ thus indicate a bad fit to the data.
This statistic is computed according to the formula
${\rm astrometric\_gof\_al}=(9\nu/2)^{1/2}[(\chi^{2}/\nu)^{1/3}+2/(9\nu)-1]$
where $\chi^{2}={\tt astrometric\_chi2\_al}$ is the AL chi-square statistic and
$\nu={\tt astrometric\_n\_good\_obs\_al}-N$
is the number of degrees of freedom for a source update. Here $N=5$ is the number of astrometric parameters. Note that only ‘good’ (i.e. not strongly downweighted) observations are included in $\chi^{2}$ and $\nu$.
The above formula is the well-known cube-root transformation of the chi-square variable (E.B. Wilson & M.M. Hilferty 1931, Proc. National Academy of Science, 17, 684). It is usually quoted to be valid for $\nu>30$, but is in fact useful for much smaller $\nu$. This transformation of $(\chi^{2},\nu)$ eliminates the inconvenience of having the distribution (and hence the significance levels) depend on the additional variable $\nu$, which is generally not the same for different sources.
An alternative indicator of bad fits is the $\tt astrometric\_excess\_noise$. In AGIS the source update deals with bad fits by adding $\tt astrometric\_excess\_noise$ to the formal observation noise. This reduces the weight of the observations and inflates the covariance of the estimated astrometric parameters correspondingly. However, the chi-square values used to calculate $\tt astrometric\_gof\_al$ do not take into account the $\tt astrometric\_excess\_noise$, and $\tt astrometric\_gof\_al$ can therefore always be used as a goodness-of-fit indicator of the source solution in AGIS.
astrometric_chi2_al : AL chi-square value (float)
Astrometric goodness-of-fit ($\chi^{2}$) in the AL direction.
$\chi^{2}$ values were computed for the ‘good’ AL observations of the source, without taking into account the $\tt astrometric\_excess\_noise$ (if any) of the source. They do however take into account the attitude excess noise (if any) of each observation.
astrometric_excess_noise : Excess noise of the source (double, Angle[mas])
This is the excess noise $\epsilon_{i}$ of the source. It measures the disagreement, expressed as an angle, between the observations of a source and the best-fitting standard astrometric model (using five astrometric parameters). The assumed observational noise in each observation is quadratically increased by $\epsilon_{i}$ in order to statistically match the residuals in the astrometric solution. A value of 0 signifies that the source is astrometrically well-behaved, i.e. that the residuals of the fit statistically agree with the assumed observational noise. A positive value signifies that the residuals are statistically larger than expected.
The significance of $\epsilon_{i}$ is given by astrometric_excess_noise_sig ($D$). If $D\leq 2$ then $\epsilon_{i}$ is probably not significant, and the source may be astrometrically well-behaved even if $\epsilon_{i}$ is large.
The excess noise $\epsilon_{i}$ may absorb all kinds of modelling errors that are not accounted for by the observational noise (image centroiding error) or the excess attitude noise. Such modelling errors include LSF and PSF calibration errors, geometric instrument calibration errors, and part of the high-frequency attitude noise. These modelling errors are particularly important in the early data releases, but should decrease as the astrometric modelling of the instrument and attitude improves over the years.
Additionally, sources that deviate from the standard five-parameter astrometric model (e.g. unresolved binaries, exoplanet systems, etc.) may have positive $\epsilon_{i}$. Given the many other possible contributions to the excess noise, the user must study the empirical distributions of $\epsilon_{i}$ and $D$ to make sensible cutoffs before filtering out sources for their particular application.
The excess source noise is further explained in Sects. 3.6 and 5.1.2 of Lindegren et al. (2012).
astrometric_excess_noise_sig : Significance of excess noise (double)
A dimensionless measure ($D$) of the significance of the calculated astrometric_excess_noise ($\epsilon_{i}$). A value $D>2$ indicates that the given $\epsilon_{i}$ is probably significant.
For good fits in the limit of a large number of observations, $D$ should be zero in half of the cases and approximately follow the positive half of a normal distribution with zero mean and unit standard deviation for the other half. Consequently, $D$ is expected to be greater than 2 for only a few percent of the sources with well-behaved astrometric solutions.
In the early data releases $\epsilon_{i}$ will however include instrument and attitude modelling errors that are statistically significant and could result in large values of $\epsilon_{i}$ and $D$. The user must study the empirical distributions of these statistics and make sensible cutoffs before filtering out sources for their particular application.
The excess noise significance is further explained in Sect. 5.1.2 of Lindegren et al. (2012).
astrometric_params_solved : Which parameters have been solved for? (byte)
This is a binary code indicating which astrometric parameters were estimated for the source. A set bit means the parameter was estimated. The least-significant bit represents $\alpha$, the next bits $\delta$, $\varpi$, $\mu_{\alpha*}$, and $\mu_{\delta}$. For Gaia DR2 the only relevant values are
• ${\tt astrometric\_params\_solved}=31$ (binary 11111): all five astrometric parameters were estimated
• ${\tt astrometric\_params\_solved}=3$ (binary 11): only position ($\alpha$, $\delta$) was estimated
astrometric_primary_flag : Primary or seconday (boolean)
Flag indicating if this source was used as a primary source (true) or secondary source (false). Only primary sources contribute to the estimation of attitude, calibration, and global parameters. The estimation of source parameters is otherwise done in exactly the same way for primary and secondary sources.
astrometric_weight_al : Mean astrometric weight of the source (float, Angle[$mas^{-2}$])
Mean astrometric weight of the source in the AL direction.
The mean astrometric weight of the source is calculated as per Eq. (119) in Lindegren et al. (2012).
astrometric_pseudo_colour : Astrometrically determined pseudocolour of the source (double, Misc[$\mu m^{-1}$])
Colour of the source assumed in the final astrometric processing.
The astrometric_pseudo_colour is defined to be equivalent to the effective wavenumber of the photon flux distribution in the astrometric ($G$) band, and is measured in $\mu$m${}^{-1}$. The value given in this field was astrometrically determined in a preliminary solution, using the chromatic displacement of image centroids calibrated by means of the effective wavenumbers ($\nu_{\text{eff}}$) of primary sources calculated from BP and RP magnitudes. The field is empty when no such determination was possible, in which case a default value of 1.6 $\mu$m${}^{-1}$ was assumed.
astrometric_pseudo_colour_error : Standard error of the pseudocolour of the source (double, Misc[$\mu m^{-1}$])
Standard error $\sigma_{pseudocolour}$ of the astrometrically determined pseudocolour of the source.
mean_varpi_factor_al : Mean Parallax factor AL (float)
Mean parallax factor in the AL direction, computed from all the good observations of the source processed in the astrometry.
The AL parallax factor for an individual observation is defined as $\partial\eta/\partial\varpi$, where $\eta$ is the AL field angle of the source and $\varpi$ its parallax, and is constrained to $[-0.73,+0.73]$ by the scanning law. The value given in this field is typically in the range $[-0.23,+0.32]$ (1st and 99th percentiles). A value outside this range indicates a distribution of observations that is unfavourable for the determination of the parallax, and the calculated parallax could then be more vulnerable to errors, e.g. from the calibration model, not reflected in the formal uncertainties. See Lindegren et al. (2018) for a discussion of other astrometric quality indicators.
astrometric_matched_observations : Matched FOV transits used in the AGIS solution (short)
The number of FOV transits matched to this source, counting only the transits containing CCD observations actually used to compute the astrometric solution.
This number will always be equal to or smaller than the matched_observations, the difference being the FOV transits that were not used in the astrometric solution because of bad data or excluded time intervals.
visibility_periods_used : Number of visibility periods used in Astrometric solution (short)
Number of visibility periods used in the astrometric solution.
A visibility period is a group of observations separated from other groups by a gap of at least 4 days. A source may have from one to tens of FOV transits in a visibility period, but with a small spread in time, direction of scanning, and parallax factor. From one visibility period to the next these variables have usually changed significantly. A high number of visibility periods is therefore a better indicator of an astrometrically well-observed source than a large number of FOV transits (matched_observations or astrometric_matched_observations) or CCD transits (astrometric_n_obs_al). A small value (e.g. less than 10) indicates that the calculated parallax could be more vulnerable to errors, e.g. from the calibration model, not reflected in the formal uncertainties. See Lindegren et al. (2018) for a discussion of this and other astrometric quality indicators.
astrometric_sigma5d_max : The longest semi-major axis of the 5-d error ellipsoid (float, Angle[mas])
The longest principal axis in the 5-dimensional error ellipsoid.
This is a 5-dimensional equivalent to the semi-major axis of the position error ellipse and is therefore useful for filtering out cases where one of the five parameters, or some linear combination of several parameters, is particularly ill-determined. It is measured in mas and computed as the square root of the largest singular value of the scaled $5\times 5$ covariance matrix of the astrometric parameters. The matrix is scaled so as to put the five parameters on a comparable scale, taking into account the maximum along-scan parallax factor for the parallax and the time coverage of the observations for the proper motion components. If $C$ is the unscaled covariance matrix, the scaled matrix is $SCS$, where $S=\text{diag}(1,1,\sin\xi,T/2,T/2)$, $\xi=45^{\circ}$ is the solar aspect angle in the nominal scanning law, and $T$ the time coverage of the data used in the solution. $T=1.75115$ yr for Gaia DR2.
astrometric_sigma5d_max is given for both 5-parameter and 2-parameter solutions, as its size is one of the criteria for accepting or rejecting the 5-parameter solution. In case of a 2-parameter solution (astrometric_params_solved = 3) it gives the value for the rejected 5-parameter solution, and can then be arbitrarily large.
frame_rotator_object_type : The type of the source mainly used for frame rotation (int)
This field is non-zero if the source was used to define the reference frame of the positions and proper motions.
The values used are:
0: An ordinary source not used for the reference frame determination
2: The optical counterpart of an extragalactic radio source with accurately known VLBI position in ICRF. This is used to determine the orientation of the reference frame at the reference epoch, but also contributes to the determination of a non-rotating frame.
3: An extragalactic source (AGN or quasar) that was used to determine a kinematically non-rotating celestial frame.
matched_observations : Amount of observations matched to this source (short)
The total number of FOV transits matched to this source.
duplicated_source : Source with duplicate sources (boolean)
During data processing, this source happened to be duplicated and only one source identifier has been kept. Observations assigned to the discarded source identifier(s) were not used. This may indicate observational, cross-matching or processing problems, or stellar multiplicity, and probable astrometric or photometric problems in all cases. In Gaia DR1 and DR2, for close doubles with separations below some 2 arcsec, truncated windows have not been processed, neither in astrometry nor photometry. The transmitted window is centred on the brighter part of the acquired window, so the brighter component has a better chance to be selected, even when processing the fainter transit. If more than two images are contained in a window, the result of the image parameter determination is unpredictable in the sense that it might refer to either (or neither) image, and no consistency is assured.
phot_g_n_obs : Number of observations contributing to G photometry (int)
Number of observations (CCD transits) that contributed to the G mean flux and mean flux error.
phot_g_mean_flux : G-band mean flux (double, Flux[e-/s])
Mean flux in the G-band.
phot_g_mean_flux_error : Error on G-band mean flux (double, Flux[e-/s])
Standard deviation of the G-band fluxes divided by sqrt(phot_g_n_obs)
phot_g_mean_flux_over_error : G-band mean flux divided by its error (float)
Mean flux in the G-band divided by its error.
phot_g_mean_mag : G-band mean magnitude (float, Magnitude[mag])
Mean magnitude in the G band. This is computed from the G-band mean flux applying the magnitude zero-point in the Vega scale.
No error is provided for this quantity as the error distribution is only symmetric in flux space. This converts to an asymmetric error distribution in magnitude space which cannot be represented by a single error value.
phot_bp_n_obs : Number of observations contributing to BP photometry (int)
Number of observations (CCD transits) that contributed to the integrated BP mean flux and mean flux error.
phot_bp_mean_flux : Integrated BP mean flux (double, Flux[e-/s])
Mean flux in the integrated BP band.
phot_bp_mean_flux_error : Error on the integrated BP mean flux (double, Flux[e-/s])
Error on the mean flux in the integrated BP band (errors are computed from the dispersion about the weighted mean of input calibrated photometry).
phot_bp_mean_flux_over_error : Integrated BP mean flux divided by its error (float)
Integrated BP mean flux divided by its error.
phot_bp_mean_mag : Integrated BP mean magnitude (float, Magnitude[mag])
Mean magnitude in the integrated BP band. This is computed from the BP-band mean flux applying the magnitude zero-point in the Vega scale.
No error is provided for this quantity as the error distribution is only symmetric in flux space. This converts to an asymmetric error distribution in magnitude space which cannot be represented by a single error value.
phot_rp_n_obs : Number of observations contributing to RP photometry (int)
Number of observations (CCD transits) that contributed to the integrated RP mean flux and mean flux error.
phot_rp_mean_flux : Integrated RP mean flux (double, Flux[e-/s])
Mean flux in the integrated RP band.
phot_rp_mean_flux_error : Error on the integrated RP mean flux (double, Flux[e-/s])
Error on the mean flux in the integrated RP band (errors are computed from the dispersion about the weighted mean of input calibrated photometry).
phot_rp_mean_flux_over_error : Integrated RP mean flux divided by its error (float)
Integrated RP mean flux divided by its error.
phot_rp_mean_mag : Integrated RP mean magnitude (float, Magnitude[mag])
Mean magnitude in the integrated RP band. This is computed from the RP-band mean flux applying the magnitude zero-point in the Vega scale.
No error is provided for this quantity as the error distribution is only symmetric in flux space. This converts to an asymmetric error distribution in magnitude space which cannot be represented by a single error value.
phot_bp_rp_excess_factor : BP/RP excess factor (float)
BP/RP excess factor estimated from the comparison of the sum of integrated BP and RP fluxes with respect to the flux in the G band. This measures the excess of flux in the BP and RP integrated photometry with respect to the G band. This excess is believed to be caused by background and contamination issues affecting the BP and RP data. Therefore a large value of this factor for a given source indicates systematic errors in the BP and RP photometry.
For more details see Riello et al. (2018).
phot_proc_mode : Photometry processing mode (byte)
This flag indicates different calibration procedures in place. The following possible values are defined for Gaia DR2:
• 0: this corresponds to the procedure applied for the generation of the ”gold” photometric dataset. Sources in this dataset have been used to establish the internal photometric system and to compute all calibrations.
• 1: this corresponds to the procedure applied for the generation of the ”silver” photometric dataset. Sources in this dataset have no reference photometry. The processing of these sources is an iterative process, where calibrations computed using the ”gold” dataset are applied initially to raw fluxes and at each iteration a new set of reference photometry is obtained from the accumulation of all calibrated epoch photometry.
• 2: this corresponds to the procedure applied for the generation of the ”bronze” photometric dataset. Sources in this dataset lack complete colour information in the Gaia data. A default colour is therefore used to apply the calibrations computed using the ”gold” dataset. For Gaia DR2 it is expected that all sources that were calibrated using a default colour will have only G band photometry available (no integrated BP or RP).
More details about the different calibration procedures are available in Chapter 5 of the Gaia DR2 on-line documentation and in Riello et al. (2018).
bp_rp : BP - RP colour (float, Magnitude[mag])
BP - RP colour: phot_bp_mean_mag - phot_rp_mean_mag
bp_g : BP - G colour (float, Magnitude[mag])
BP - G colour: phot_bp_mean_mag - phot_g_mean_mag
g_rp : G - RP colour (float, Magnitude[mag])
G - RP colour: phot_g_mean_mag - phot_rp_mean_mag
Spectroscopic radial velocity in the solar barycentric reference frame.
The radial velocity provided is the median value of the radial velocity measurements at all epochs.
The radial_velocity_error is the error on the median to which a constant noise floor of 0.11 km/s has been added in quadrature to take into account the calibration contribution.
In detail, radial_velocity_error = $\sqrt{\sigma^{2}_{V_{\rm rad}}+0.11^{2}}$ where $\sigma_{V_{\rm rad}}$ is the error on the median:
$\sigma_{V_{\rm rad}}=\sqrt{\frac{\pi}{2}}.\frac{\sigma(V_{\rm rad}^{\rm t})}{% \sqrt{\tt rv\_nb\_transits}}$
where $\sigma(V_{\rm rad}^{\rm t})$ is the standard deviation of the epoch radial velocities and ${\tt rv\_nb\_transits}$ the number of transits for which a $V_{\rm rad}^{\rm t}$ has been obtained.
rv_nb_transits : Number of transits used to compute radial velocity (int)
number of transits (epochs) used to compute radial_velocity
rv_template_teff : Teff of the template used to compute radial velocity (float, Temperature[K])
Effective temperature of the synthetic spectrum template used to determine radial_velocity. N.B. the purpose of this parameter is to provide information on the synthetic template spectrum used to determine radial_velocity, and not to provide an estimate of the stellar effective temperature of this source.
rv_template_logg : logg of the template used to compute radial velocity (float, GravitySurface[log cgs])
$\log g$ of the synthetic spectrum template used to determine radial_velocity. N.B. the purpose of this parameter is to provide information on the synthetic template spectrum used to determine radial_velocity, and not to provide an estimate of the $\log g$ of this source.
rv_template_fe_h : Fe/H of the template used to compute radial velocity (float, Abundances[dex])
Fe/H of the synthetic spectrum template used to determine radial_velocity. N.B. the purpose of this parameter is to provide information on the synthetic template spectrum used to determine radial_velocity, and not to provide an estimate of the stellar atmospheric Fe/H of this source.
phot_variable_flag : Photometric variability flag (string, Dimensionless[see description])
Flag indicating if variability was identified in the photometric data:
• ”NOT_AVAILABLE”: source not processed and/or exported to catalogue
• ”CONSTANT”: Source not identified as variable
• ”VARIABLE”: source identified and processed as variable, see Vari* tables.
Note that for this data release only a subset of (variable) sources was processed and/or exported, so for many (known) variable sources this flag is set to ”NOT AVAILABLE”. No ”CONSTANT” sources were exported either.
l : Galactic longitude (double, Angle[deg])
Galactic Longitude of the object at reference epoch ref_epoch, see Section 3.1.7 of the release documentation for conversion details.
b : Galactic latitude (double, Angle[deg])
Galactic Latitude of the object at reference epoch ref_epoch, see Section 3.1.7 of the release documentation for conversion details.
ecl_lon : Ecliptic longitude (double, Angle[deg])
Ecliptic Longitude of the object at reference epoch ref_epoch, obtained from the equatorial coordinates using the transformation defined in Section 1.5.3 of ‘The Hipparcos and Tycho Catalogues’, ESA SP-1200, Volume 1 (ESA, 1997).
ecl_lat : Ecliptic latitude (double, Angle[deg])
Ecliptic Latitude of the object at reference epoch ref_epoch, obtained from the equatorial coordinates using the transformation defined in Section 1.5.3 of ‘The Hipparcos and Tycho Catalogues’, ESA SP-1200, Volume 1 (ESA, 1997).
priam_flags : flags for the Apsis-Priam results (long, Dimensionless[see description])
Flags describing the status of the astrophysical parameters Teff, A${}_{G}$ and E[BP-RP] (i.e. those determined by Apsis-Priam). They are described in Chapter 8 of the release documentation.
teff_val : stellar effective temperature (float, Temperature[K])
Estimate of Teff from Apsis-Priam
teff_percentile_lower : teff_val lower uncertainty (float, Temperature[K])
Uncertainty (lower) on Teff estimate from Apsis-Priam. This is the 16th percentile of the PDF over Teff.
teff_percentile_upper : teff_val upper uncertainty (float, Temperature[K])
Uncertainty (upper) on Teff estimate from Apsis-Priam. This is the 84th percentile of the PDF over Teff.
a_g_val : line-of-sight extinction in the G band, A_G (float, Magnitude[mag])
Estimate of extinction in the G band from Apsis-Priam
a_g_percentile_lower : a_g_val lower uncertainty (float, Magnitude[mag])
Uncertainty (lower) on A${}_{G}$ estimate from Apsis-Priam. This is the 16th percentile of the PDF over A${}_{G}$.
a_g_percentile_upper : a_g_val upper uncertainty (float, Magnitude[mag])
Uncertainty (upper) on A${}_{G}$ estimate from Apsis-Priam. This is the 84th percentile of the PDF over A${}_{G}$.
e_bp_min_rp_val : line-of-sight reddening E(BP-RP) (float, Magnitude[mag])
Estimate of redenning E[BP-RP] from Apsis-Priam.
e_bp_min_rp_percentile_lower : e_bp_min_rp_val lower uncertainty (float, Magnitude[mag])
Uncertainty (lower) on E[BP-RP] estimate from Apsis-Priam. This is the 16th percentile of the PDF over E[BP-RP].
e_bp_min_rp_percentile_upper : e_bp_min_rp_val upper uncertainty (float, Magnitude[mag])
Uncertainty (upper) on E[BP-RP] estimate from Apsis-Priam. This is the 84th percentile of the PDF over E[BP-RP].
flame_flags : Flags for the Apsis-FLAME results (long, Dimensionless[see description])
Flags describing the status of the astrophysical parameters radius and luminosity (i.e. those determined by Apsis-FLAME). They are described in Chapter 8 of the release documentation. Note that at DR2 there is just one value of this field defined for the entire catalogue.
Uncertainty (lower) on radius estimate from Apsis-FLAME. This is the 16th percentile of the PDF over radius.
Uncertainty (upper) on radius estimate from Apsis-FLAME. This is the 84th percentile of the PDF over radius.
lum_val : stellar luminosity (float, Luminosity[Solar Luminosity])
Esimate of luminosity from Apsis-FLAME
lum_percentile_lower : lum_val lower uncertainty (float, Luminosity[Solar Luminosity])
Uncertainty (lower) on luminosity estimate from Apsis-FLAME. This is the 16th percentile of the PDF over luminosity.
lum_percentile_upper : lum_val upper uncertainty (float, Luminosity[Solar Luminosity])
Uncertainty (upper) on luminosity estimate from Apsis-FLAME. This is the 84th percentile of the PDF over luminosity.
| 2019-02-22T13:06:24 |
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https://pos.sissa.it/282/469/
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Volume 282 - 38th International Conference on High Energy Physics (ICHEP2016) - Neutrino Physics
First double-detector results from Double Chooz experiment
T. Matsubara* On behalf of the Double-Chooz Collaboration
*corresponding author
Full text: pdf
Pre-published on: 2017 February 06
Published on: 2017 April 19
Abstract
We report preliminary results of first $\theta_{13}$ measurements from the Double Chooz experiment with double-detector setup. In addition to the Far detector operation at ∼1 km baseline since 2011, we started the Near detector operation at ∼400 m baseline since beginning 2015, which allows us to reach significantly improved sensitivity of the neutrino mixing angle θ13. From oscillation analysis using rate and spectral shape, we obtained $\sin^22\theta_{13}$ = 0.111 $\pm$ 0.018 with $\chi^2$/ndf = 128.8/120, combining 1 year of double-detector and 2 years of single-detector data. We also reported current efforts to reach better sensitivity with improved analysis as well as other physics programs.
Open Access
Copyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
| 2018-02-22T10:50:08 |
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https://zims-en.kiwix.campusafrica.gos.orange.com/wikipedia_en_all_nopic/A/Condition_number
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# Condition number
In the field of numerical analysis, the condition number of a function measures how much the output value of the function can change for a small change in the input argument. This is used to measure how sensitive a function is to changes or errors in the input, and how much error in the output results from an error in the input. Very frequently, one is solving the inverse problem: given ${\displaystyle f(x)=y,}$ one is solving for x, and thus the condition number of the (local) inverse must be used. In linear regression the condition number of the moment matrix can be used as a diagnostic for multicollinearity.[1][2]
The condition number is an application of the derivative, and is formally defined as the value of the asymptotic worst-case relative change in output for a relative change in input. The "function" is the solution of a problem and the "arguments" are the data in the problem. The condition number is frequently applied to questions in linear algebra, in which case the derivative is straightforward but the error could be in many different directions, and is thus computed from the geometry of the matrix. More generally, condition numbers can be defined for non-linear functions in several variables.
A problem with a low condition number is said to be well-conditioned, while a problem with a high condition number is said to be ill-conditioned. The condition number is a property of the problem. Paired with the problem are any number of algorithms that can be used to solve the problem, that is, to calculate the solution. Some algorithms have a property called backward stability. In general, a backward stable algorithm can be expected to accurately solve well-conditioned problems. Numerical analysis textbooks give formulas for the condition numbers of problems and identify known backward stable algorithms.
As a rule of thumb, if the condition number ${\displaystyle \kappa (A)=10^{k}}$, then you may lose up to ${\displaystyle k}$ digits of accuracy on top of what would be lost to the numerical method due to loss of precision from arithmetic methods.[3] However, the condition number does not give the exact value of the maximum inaccuracy that may occur in the algorithm. It generally just bounds it with an estimate (whose computed value depends on the choice of the norm to measure the inaccuracy).
## General definition in the context of error analysis
Given a problem ${\displaystyle f}$ and an algorithm ${\displaystyle {\tilde {f}}}$ with an input x, the absolute error is ${\displaystyle \left\|f(x)-{\tilde {f}}(x)\right\|}$ and the relative error is ${\displaystyle \left\|f(x)-{\tilde {f}}(x)\right\|/\left\|f(x)\right\|}$.
In this context, the absolute condition number of a problem f is
${\displaystyle \lim _{\varepsilon \rightarrow 0}\sup _{\|\delta x\|\leq \varepsilon }{\frac {\|\delta f\|}{\|\delta x\|}}}$
and the relative condition number is
${\displaystyle \lim _{\varepsilon \rightarrow 0}\sup _{\|\delta x\|\leq \varepsilon }{\frac {\|\delta f(x)\|/\|f(x)\|}{\|\delta x\|/\|x\|}}}$
## Matrices
For example, the condition number associated with the linear equation Ax = b gives a bound on how inaccurate the solution x will be after approximation. Note that this is before the effects of round-off error are taken into account; conditioning is a property of the matrix, not the algorithm or floating point accuracy of the computer used to solve the corresponding system. In particular, one should think of the condition number as being (very roughly) the rate at which the solution, x, will change with respect to a change in b. Thus, if the condition number is large, even a small error in b may cause a large error in x. On the other hand, if the condition number is small then the error in x will not be much bigger than the error in b.
The condition number is defined more precisely to be the maximum ratio of the relative error in x to the relative error in b.
Let e be the error in b. Assuming that A is a nonsingular matrix, the error in the solution A−1b is A−1e. The ratio of the relative error in the solution to the relative error in b is
${\displaystyle {\frac {\frac {\left\|A^{-1}e\right\|}{\left\|A^{-1}b\right\|}}{\frac {\|e\|}{\|b\|}}}}$
This is easily transformed to
${\displaystyle {\frac {\left\|A^{-1}e\right\|}{\|e\|}}{\frac {\|b\|}{\left\|A^{-1}b\right\|}}.}$
The maximum value (for nonzero b and e) is then seen to be the product of the two operator norms as follows:
{\displaystyle {\begin{aligned}\max _{e,b\neq 0}\left\{{\frac {\left\|A^{-1}e\right\|}{\|e\|}}{\frac {\|b\|}{\left\|A^{-1}b\right\|}}\right\}&=\max _{e\neq 0}\left\{{\frac {\left\|A^{-1}e\right\|}{\|e\|}}\right\}\,\max _{b\neq 0}\left\{{\frac {\|b\|}{\left\|A^{-1}b\right\|}}\right\}\\&=\max _{e\neq 0}\left\{{\frac {\left\|A^{-1}e\right\|}{\|e\|}}\right\}\,\max _{x\neq 0}\left\{{\frac {\|Ax\|}{\|x\|}}\right\}\\&=\left\|A^{-1}\right\|\,\|A\|\end{aligned}}}
The same definition is used for any consistent norm, i.e. one that satisfies
${\displaystyle \kappa (A)=\left\|A^{-1}\right\|\,\left\|A\right\|\geq \left\|A^{-1}A\right\|=1.}$
When the condition number is exactly one (which can only happen if A is a scalar multiple of a linear isometry), then a solution algorithm can find (in principle, meaning if the algorithm introduces no errors of its own) an approximation of the solution whose precision is no worse than that of the data.
However, it does not mean that the algorithm will converge rapidly to this solution, just that it won't diverge arbitrarily because of inaccuracy on the source data (backward error), provided that the forward error introduced by the algorithm does not diverge as well because of accumulating intermediate rounding errors.
The condition number may also be infinite, but this implies that the problem is ill-posed (does not possess a unique, well-defined solution for each choice of data; that is, the matrix is not invertible), and no algorithm can be expected to reliably find a solution.
The definition of the condition number depends on the choice of norm, as can be illustrated by two examples.
If ${\displaystyle \|\cdot \|}$ is the norm defined in the square-summable sequence space 2 (which matches the usual distance in a standard Euclidean space and is usually noted as ${\displaystyle \|\cdot \|_{2}}$), then
${\displaystyle \kappa (A)={\frac {\sigma _{\max }(A)}{\sigma _{\min }(A)}},}$
where ${\displaystyle \sigma _{\max }(A)}$ and ${\displaystyle \sigma _{\min }(A)}$ are maximal and minimal singular values of ${\displaystyle A}$ respectively. Hence
• If ${\displaystyle A}$ is normal then
${\displaystyle \kappa (A)={\frac {\left|\lambda _{\max }(A)\right|}{\left|\lambda _{\min }(A)\right|}},}$
where ${\displaystyle \lambda _{\max }(A)}$ and ${\displaystyle \lambda _{\min }(A)}$ are maximal and minimal (by moduli) eigenvalues of ${\displaystyle A}$ respectively.
• If ${\displaystyle A}$ is unitary then ${\displaystyle \kappa (A)=1.}$
The condition number with respect to L2 arises so often in numerical linear algebra that it is given a name, the condition number of a matrix.
If ${\displaystyle \|\cdot \|}$ is the norm defined in the sequence space of all bounded sequences (which matches the maximum of distances measured on projections into the base subspaces and is usually denoted by ${\displaystyle \|\cdot \|_{\infty }}$), and ${\displaystyle A}$ is lower triangular non-singular (i.e., ${\displaystyle \forall i,a_{ii}\neq 0}$) then
${\displaystyle \kappa (A)\geq {\frac {\max _{i}(|a_{ii}|)}{\min _{i}(|a_{ii}|)}}.}$
The condition number computed with this norm is generally larger than the condition number computed with square-summable sequences, but it can be evaluated more easily (and this is often the only practicably computable condition number, when the problem to solve involves a non-linear algebra, for example when approximating irrational and transcendental functions or numbers with numerical methods).
If the condition number is not too much larger than one, the matrix is well conditioned which means its inverse can be computed with good accuracy. If the condition number is very large, then the matrix is said to be ill-conditioned. Practically, such a matrix is almost singular, and the computation of its inverse, or solution of a linear system of equations is prone to large numerical errors. A matrix that is not invertible has condition number equal to infinity.
## Nonlinear
Condition numbers can also be defined for nonlinear functions, and can be computed using calculus. The condition number varies with the point; in some cases one can use the maximum (or supremum) condition number over the domain of the function or domain of the question as an overall condition number, while in other cases the condition number at a particular point is of more interest.
### One variable
The condition number of a differentiable function ${\displaystyle f}$ in one variable as a function is ${\displaystyle \left|xf'/f\right|}$. Evaluated at a point ${\displaystyle x}$ this is:
${\displaystyle \left|{\frac {xf'(x)}{f(x)}}\right|}$
Most elegantly, this can be understood as (the absolute value of) the ratio of the logarithmic derivative of ${\displaystyle f}$, which is ${\displaystyle (\log f)'=f'/f}$ and the logarithmic derivative of ${\displaystyle x}$, which is ${\displaystyle (\log x)'=x'/x=1/x}$, yielding a ratio of ${\displaystyle xf'/f}$. This is because the logarithmic derivative is the infinitesimal rate of relative change in a function: it is the derivative ${\displaystyle f'}$ scaled by the value of ${\displaystyle f}$. Note that if a function has a zero at a point, its condition number at the point is infinite, as infinitesimal changes in the input can change the output from zero to positive or negative, yielding a ratio with zero in the denominator, hence infinite relative change.
More directly, given a small change ${\displaystyle \Delta x}$ in ${\displaystyle x}$, the relative change in ${\displaystyle x}$ is ${\displaystyle [(x+\Delta x)-x]/x=(\Delta x)/x}$, while the relative change in ${\displaystyle f(x)}$ is ${\displaystyle [f(x+\Delta x)-f(x)]/f(x)}$. Taking the ratio yields:
${\displaystyle {\frac {[f(x+\Delta x)-f(x)]/f(x)}{(\Delta x)/x}}={\frac {x}{f(x)}}{\frac {f(x+\Delta x)-f(x)}{(x+\Delta x)-x}}={\frac {x}{f(x)}}{\frac {f(x+\Delta x)-f(x)}{\Delta x}}}$.
The last term is the difference quotient (the slope of the secant line), and taking the limit yields the derivative.
Condition numbers of common elementary functions are particularly important in computing significant figures, and can be computed immediately from the derivative; see significance arithmetic of transcendental functions. A few important ones are given below:
Name Symbol Condition number
Addition / Subtraction ${\displaystyle x+a}$ ${\displaystyle \left|{\frac {x}{x+a}}\right|}$
Scalar Multiplication ${\displaystyle ax}$ ${\displaystyle 1}$
Division ${\displaystyle 1/x}$ ${\displaystyle 1}$
Polynomial ${\displaystyle x^{n}}$ ${\displaystyle |n|}$
Exponential function ${\displaystyle e^{x}}$ ${\displaystyle |x|}$
Natural logarithm function ${\displaystyle \ln(x)}$ ${\displaystyle \left|{\frac {1}{\ln(x)}}\right|}$
Sine function ${\displaystyle \sin(x)}$ ${\displaystyle |x\cot(x)|}$
Cosine function ${\displaystyle \cos(x)}$ ${\displaystyle |x\tan(x)|}$
Tangent function ${\displaystyle \tan(x)}$ ${\displaystyle |x(\tan(x)+\cot(x))|}$
Inverse sine function ${\displaystyle \arcsin(x)}$ ${\displaystyle {\frac {x}{{\sqrt {1-x^{2}}}\arcsin(x)}}}$
Inverse cosine function ${\displaystyle \arccos(x)}$ ${\displaystyle {\frac {|x|}{{\sqrt {1-x^{2}}}\arccos(x)}}}$
Inverse tangent function ${\displaystyle \arctan(x)}$ ${\displaystyle {\frac {x}{(1+x^{2})\arctan(x)}}}$
### Several variables
Condition numbers can be defined for any function ${\displaystyle f}$ mapping its data from some domain (e.g. an ${\displaystyle m}$-tuple of real numbers ${\displaystyle x}$) into some codomain (e.g. an ${\displaystyle n}$-tuple of real numbers ${\displaystyle f(x)}$), where both the domain and codomain are Banach spaces. They express how sensitive that function is to small changes (or small errors) in its arguments. This is crucial in assessing the sensitivity and potential accuracy difficulties of numerous computational problems, for example polynomial root finding or computing eigenvalues.
The condition number of ${\displaystyle f}$ at a point ${\displaystyle x}$ (specifically, its relative condition number[4]) is then defined to be the maximum ratio of the fractional change in ${\displaystyle f(x)}$ to any fractional change in ${\displaystyle x}$, in the limit where the change ${\displaystyle \delta x}$ in ${\displaystyle x}$ becomes infinitesimally small:[4]
${\displaystyle \lim _{\varepsilon \to 0^{+}}\sup _{\|\delta x\|\leq \varepsilon }\left[\left.{\frac {\left\|f(x+\delta x)-f(x)\right\|}{\|f(x)\|}}\right/{\frac {\|\delta x\|}{\|x\|}}\right]}$,
where ${\displaystyle \|\cdot \|}$ is a norm on the domain/codomain of ${\displaystyle f}$.
If ${\displaystyle f}$ is differentiable, this is equivalent to:[4]
${\displaystyle {\frac {\|J(x)\|}{\|f(x)\|/\|x\|}}}$,
where ${\displaystyle J(x)}$ denotes the Jacobian matrix of partial derivatives of ${\displaystyle f}$ at ${\displaystyle x}$ and ${\displaystyle \|J(x)\|}$ is the induced norm on the matrix.
## References
1. Belsley, David A.; Kuh, Edwin; Welsch, Roy E. (1980). "The Condition Number". Regression Diagnostics: Identifying Influential Data and Sources of Collinearity. New York: John Wiley & Sons. pp. 100–104. ISBN 0-471-05856-4.
2. Pesaran, M. Hashem (2015). "The Multicollinearity Problem". Time Series and Panel Data Econometrics. New York: Oxford University Press. pp. 67–72 [p. 70]. ISBN 978-0-19-875998-0.
3. Cheney; Kincaid (2007-08-03). Numerical Mathematics and Computing. ISBN 978-0-495-11475-8.
4. Trefethen, L. N.; Bau, D. (1997). Numerical Linear Algebra. SIAM. ISBN 978-0-89871-361-9.
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| 2022-09-28T01:06:35 |
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## Numerical Simulation of Diffusion Equation by Means of He's Variational Iteration Method and Adomian's Decomposition Method
#### Hikmet Koyunbakan [1] , Emrah Yılmaz [2]
##### 159 813
In this study, we obtain approximate solutions for diffusion equation on a finite interval by the Adomian decomposition method (ADM) and variational iteration method (VIM) for three cases and then the numerical results are compared. These results show that the ADM leads to more accurate results, and they indicate that only a few terms are sufficient to obtain accurate solutions.
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Birincil Dil tr Mühendislik Makaleler Yazar: Hikmet Koyunbakan Yazar: Emrah Yılmaz
Bibtex @ { cankujse53215, journal = {Çankaya Üniversitesi Bilim ve Mühendislik Dergisi}, issn = {1309-6788}, eissn = {2564-7954}, address = {Çankaya Üniversitesi}, year = {}, volume = {7}, pages = { - }, doi = {}, title = {Numerical Simulation of Diffusion Equation by Means of He's Variational Iteration Method and Adomian's Decomposition Method}, key = {cite}, author = {Koyunbakan, Hikmet and Yılmaz, Emrah} } APA Koyunbakan, H , Yılmaz, E . (). Numerical Simulation of Diffusion Equation by Means of He's Variational Iteration Method and Adomian's Decomposition Method. Çankaya Üniversitesi Bilim ve Mühendislik Dergisi, 7 (1), . Retrieved from http://dergipark.gov.tr/cankujse/issue/4033/53215 MLA Koyunbakan, H , Yılmaz, E . "Numerical Simulation of Diffusion Equation by Means of He's Variational Iteration Method and Adomian's Decomposition Method". Çankaya Üniversitesi Bilim ve Mühendislik Dergisi 7 (): Chicago Koyunbakan, H , Yılmaz, E . "Numerical Simulation of Diffusion Equation by Means of He's Variational Iteration Method and Adomian's Decomposition Method". Çankaya Üniversitesi Bilim ve Mühendislik Dergisi 7 (): RIS TY - JOUR T1 - Numerical Simulation of Diffusion Equation by Means of He's Variational Iteration Method and Adomian's Decomposition Method AU - Hikmet Koyunbakan , Emrah Yılmaz Y1 - 2019 PY - 2019 N1 - DO - T2 - Çankaya Üniversitesi Bilim ve Mühendislik Dergisi JF - Journal JO - JOR SP - EP - VL - 7 IS - 1 SN - 1309-6788-2564-7954 M3 - UR - Y2 - 2019 ER - EndNote %0 Çankaya Üniversitesi Bilim ve Mühendislik Dergisi Numerical Simulation of Diffusion Equation by Means of He's Variational Iteration Method and Adomian's Decomposition Method %A Hikmet Koyunbakan , Emrah Yılmaz %T Numerical Simulation of Diffusion Equation by Means of He's Variational Iteration Method and Adomian's Decomposition Method %D 2019 %J Çankaya Üniversitesi Bilim ve Mühendislik Dergisi %P 1309-6788-2564-7954 %V 7 %N 1 %R %U ISNAD Koyunbakan, Hikmet , Yılmaz, Emrah . "Numerical Simulation of Diffusion Equation by Means of He's Variational Iteration Method and Adomian's Decomposition Method". Çankaya Üniversitesi Bilim ve Mühendislik Dergisi 7 / 1 -.
| 2019-01-19T10:57:56 |
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https://www.usgs.gov/publications/substantial-declines-salinity-observed-across-upper-colorado-river-basin-during-20th
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# Substantial declines in salinity observed across the Upper Colorado River Basin during the 20th century, 1929 to 2019
April 19, 2021
Salinity in the Colorado River Basin causes an estimated $300 to$400 million per year in economic damages in the U.S. To inform and improve salinity‐control efforts, this study quantifies long‐term trends in salinity (dissolved solids) across the Upper Colorado River Basin (UCRB), including time periods prior to the construction of large dams and preceding the implementation of salinity‐control projects. Weighted Regressions on Time, Discharge, and Season was used with datasets of dissolved‐solids and specific‐conductance measurements, collected as early as 1929, to evaluate long‐term trends in dissolved‐solids loads and concentrations in streams from 1929 to 2019 (n=14). Results indicate that large, widespread, and sustained downward trends in dissolved‐solids concentrations and loads occurred over the last 50 to 90 years. For 12 of the 14 stream sites with significant downward change, median declines of ‐38% (range of ‐14 to ‐57%) and ‐40% (range of ‐9 to ‐65%) were observed for flow‐normalized concentration and load, respectively. Steepest rates of decline occurred from 1980 to 2000, coincident with the initiation of salinity‐control efforts in the 1980s. However, there was a consistent slowing or reversing of downward trends after 2000 even though salinity‐control efforts continued. Significant decreases in salinity occurred as early as the 1940s at some streams, indicating that, in addition to salinity‐control projects, changes in land cover, land use, and/or climate substantially affect salinity transport in the UCRB. Observed dissolved‐solids trends are likely the result of changes to watershed‐related processes, not due to changes in the streamflow regime.
## Citation Information
Publication Year 2021 Substantial declines in salinity observed across the Upper Colorado River Basin during the 20th century, 1929 to 2019 10.1029/2020WR028581 Christine Rumsey, Olivia L. Miller, Robert Hirsch, Thomas M. Marston, David Susong Article Journal Article Water Resources Research 70220266 USGS Publications Warehouse Utah Water Science Center
| 2023-02-05T12:26:16 |
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https://lammps.sandia.gov/doc/dump_modify.html
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# dump_modify command
## Syntax
dump_modify dump-ID keyword values ...
• dump-ID = ID of dump to modify
• one or more keyword/value pairs may be appended
• these keywords apply to various dump styles
• keyword = append or at or buffer or delay or element or every or fileper or first or flush or format or image or label or maxfiles or nfile or pad or pbc or precision or region or refresh or scale or sfactor or sort or tfactor or thermo or thresh or time or units or unwrap
append arg = yes or no
at arg = N
N = index of frame written upon first dump
buffer arg = yes or no
delay arg = Dstep
Dstep = delay output until this timestep
element args = E1 E2 ... EN, where N = # of atom types
E1,...,EN = element name, e.g. C or Fe or Ga
every arg = N
N = dump every this many timesteps
N can be a variable (see below)
fileper arg = Np
Np = write one file for every this many processors
first arg = yes or no
flush arg = yes or no
format args = line string, int string, float string, M string, or none
string = C-style format string
M = integer from 1 to N, where N = # of per-atom quantities being output
image arg = yes or no
label arg = string
string = character string (e.g. BONDS) to use in header of dump local file
maxfiles arg = Fmax
Fmax = keep only the most recent Fmax snapshots (one snapshot per file)
nfile arg = Nf
Nf = write this many files, one from each of Nf processors
pad arg = Nchar = # of characters to convert timestep to
pbc arg = yes or no = remap atoms via periodic boundary conditions
precision arg = power-of-10 value from 10 to 1000000
region arg = region-ID or "none"
refresh arg = c_ID = compute ID that supports a refresh operation
scale arg = yes or no
sfactor arg = coordinate scaling factor (> 0.0)
sort arg = off or id or N or -N
off = no sorting of per-atom lines within a snapshot
id = sort per-atom lines by atom ID
N = sort per-atom lines in ascending order by the Nth column
-N = sort per-atom lines in descending order by the Nth column
tfactor arg = time scaling factor (> 0.0)
thermo arg = yes or no
time arg = yes or no
thresh args = attribute operator value
attribute = same attributes (x,fy,etotal,sxx,etc) used by dump custom style
operator = "<" or "<=" or ">" or ">=" or "==" or "!=" or "|^"
value = numeric value to compare to, or LAST
these 3 args can be replaced by the word "none" to turn off thresholding
units arg = yes or no
unwrap arg = yes or no
• these keywords apply only to the image and movie styles
• keyword = acolor or adiam or amap or backcolor or bcolor or bdiam or boxcolor or color or bitrate or framerate
acolor args = type color
type = atom type or range of types (see below)
color = name of color or color1/color2/...
type = atom type or range of types (see below)
diam = diameter of atoms of that type (distance units)
amap args = lo hi style delta N entry1 entry2 ... entryN
lo = number or min = lower bound of range of color map
hi = number or max = upper bound of range of color map
style = 2 letters = "c" or "d" or "s" plus "a" or "f"
"c" for continuous
"d" for discrete
"s" for sequential
"a" for absolute
"f" for fractional
delta = binsize (only used for style "s", otherwise ignored)
binsize = range is divided into bins of this width
N = # of subsequent entries
entry = value color (for continuous style)
value = number or min or max = single value within range
color = name of color used for that value
entry = lo hi color (for discrete style)
lo/hi = number or min or max = lower/upper bound of subset of range
color = name of color used for that subset of values
entry = color (for sequential style)
color = name of color used for a bin of values
backcolor arg = color
color = name of color for background
bcolor args = type color
type = bond type or range of types (see below)
color = name of color or color1/color2/...
bdiam args = type diam
type = bond type or range of types (see below)
diam = diameter of bonds of that type (distance units)
boxcolor arg = color
color = name of color for simulation box lines and processor sub-domain lines
color args = name R G B
name = name of color
R,G,B = red/green/blue numeric values from 0.0 to 1.0
bitrate arg = rate
rate = target bitrate for movie in kbps
framerate arg = fps
fps = frames per second for movie
## Examples
dump_modify 1 format line "%d %d %20.15g %g %g" scale yes
dump_modify 1 format float %20.15g scale yes
dump_modify myDump image yes scale no flush yes
dump_modify 1 region mySphere thresh x < 0.0 thresh epair >= 3.2
dump_modify xtcdump precision 10000 sfactor 0.1
dump_modify 1 every 1000 nfile 20
dump_modify 1 every v_myVar
dump_modify 1 amap min max cf 0.0 3 min green 0.5 yellow max blue boxcolor red
## Description
Modify the parameters of a previously defined dump command. Not all parameters are relevant to all dump styles.
As explained on the dump doc page, the atom/mpiio, custom/mpiio, and xyz/mpiio dump styles are identical in command syntax and in the format of the dump files they create, to the corresponding styles without “mpiio”, except the single dump file they produce is written in parallel via the MPI-IO library. Thus if a dump_modify option below is valid for the atom style, it is also valid for the atom/mpiio style, and similarly for the other styles which allow for use of MPI-IO.
These keywords apply to various dump styles, including the dump image and dump movie styles. The description gives details.
The append keyword applies to all dump styles except cfg and xtc and dcd. It also applies only to text output files, not to binary or gzipped or image/movie files. If specified as yes, then dump snapshots are appended to the end of an existing dump file. If specified as no, then a new dump file will be created which will overwrite an existing file with the same name.
The at keyword only applies to the netcdf dump style. It can only be used if the append yes keyword is also used. The N argument is the index of which frame to append to. A negative value can be specified for N, which means a frame counted from the end of the file. The at keyword can only be used if the dump_modify command is before the first command that causes dump snapshots to be output, e.g. a run or minimize command. Once the dump file has been opened, this keyword has no further effect.
The buffer keyword applies only to dump styles atom, cfg, custom, local, and xyz. It also applies only to text output files, not to binary or gzipped files. If specified as yes, which is the default, then each processor writes its output into an internal text buffer, which is then sent to the processor(s) which perform file writes, and written by those processors(s) as one large chunk of text. If specified as no, each processor sends its per-atom data in binary format to the processor(s) which perform file wirtes, and those processor(s) format and write it line by line into the output file.
The buffering mode is typically faster since each processor does the relatively expensive task of formatting the output for its own atoms. However it requires about twice the memory (per processor) for the extra buffering.
The delay keyword applies to all dump styles. No snapshots will be output until the specified Dstep timestep or later. Specifying Dstep < 0 is the same as turning off the delay setting. This is a way to turn off unwanted output early in a simulation, for example, during an equilibration phase.
The element keyword applies only to the dump cfg, xyz, and image styles. It associates element names (e.g. H, C, Fe) with LAMMPS atom types. See the list of element names at the bottom of this page.
In the case of dump cfg, this allows the AtomEye visualization package to read the dump file and render atoms with the appropriate size and color.
In the case of dump image, the output images will follow the same AtomEye convention. An element name is specified for each atom type (1 to Ntype) in the simulation. The same element name can be given to multiple atom types.
In the case of xyz format dumps, there are no restrictions to what label can be used as an element name. Any white-space separated text will be accepted.
The every keyword changes the dump frequency originally specified by the dump command to a new value. The every keyword can be specified in one of two ways. It can be a numeric value in which case it must be > 0. Or it can be an equal-style variable, which should be specified as v_name, where name is the variable name.
In this case, the variable is evaluated at the beginning of a run to determine the next timestep at which a dump snapshot will be written out. On that timestep the variable will be evaluated again to determine the next timestep, etc. Thus the variable should return timestep values. See the stagger() and logfreq() and stride() math functions for equal-style variables, as examples of useful functions to use in this context. Other similar math functions could easily be added as options for equal-style variables. Also see the next() function, which allows use of a file-style variable which reads successive values from a file, each time the variable is evaluated. Used with the every keyword, if the file contains a list of ascending timesteps, you can output snapshots whenever you wish.
Note that when using the variable option with the every keyword, you need to use the first option if you want an initial snapshot written to the dump file. The every keyword cannot be used with the dump dcd style.
For example, the following commands will write snapshots at timesteps 0,10,20,30,100,200,300,1000,2000,etc:
variable s equal logfreq(10,3,10)
dump 1 all atom 100 tmp.dump
dump_modify 1 every v_s first yes
The following commands would write snapshots at the timesteps listed in file tmp.times:
variable f file tmp.times
variable s equal next(f)
dump 1 all atom 100 tmp.dump
dump_modify 1 every v_s
Note
When using a file-style variable with the every keyword, the file of timesteps must list a first timestep that is beyond the current timestep (e.g. it cannot be 0). And it must list one or more timesteps beyond the length of the run you perform. This is because the dump command will generate an error if the next timestep it reads from the file is not a value greater than the current timestep. Thus if you wanted output on steps 0,15,100 of a 100-timestep run, the file should contain the values 15,100,101 and you should also use the dump_modify first command. Any final value > 100 could be used in place of 101.
The first keyword determines whether a dump snapshot is written on the very first timestep after the dump command is invoked. This will always occur if the current timestep is a multiple of N, the frequency specified in the dump command, including timestep 0. But if this is not the case, a dump snapshot will only be written if the setting of this keyword is yes. If it is no, which is the default, then it will not be written.
The flush keyword determines whether a flush operation is invoked after a dump snapshot is written to the dump file. A flush insures the output in that file is current (no buffering by the OS), even if LAMMPS halts before the simulation completes. Flushes cannot be performed with dump style xtc.
The format keyword can be used to change the default numeric format output by the text-based dump styles: atom, custom, cfg, and xyz styles, and their MPIIO variants. Only the line or none options can be used with the atom and xyz styles.
All the specified format strings are C-style formats, e.g. as used by the C/C++ printf() command. The line keyword takes a single argument which is the format string for an entire line of output for each atom (do not include a trailing “n”), with N fields, which you must enclose in quotes if it is more than one field. The int and float keywords take a single format argument and are applied to all integer or floating-point quantities output. The setting for M string also takes a single format argument which is used for the Mth value output in each line, e.g. the 5th column is output in high precision for “format 5 %20.15g”.
Note
When using the line keyword for the cfg style, the first two fields (atom ID and type) are not actually written into the CFG file, however you must include formats for them in the format string.
The format keyword can be used multiple times. The precedence is that for each value in a line of output, the M format (if specified) is used, else the int or float setting (if specified) is used, else the line setting (if specified) for that value is used, else the default setting is used. A setting of none clears all previous settings, reverting all values to their default format.
Note
Atom and molecule IDs are stored internally as 4-byte or 8-byte signed integers, depending on how LAMMPS was compiled. When specifying the format int option you can use a “%d”-style format identifier in the format string and LAMMPS will convert this to the corresponding 8-byte form if it is needed when outputting those values. However, when specifying the line option or format M string option for those values, you should specify a format string appropriate for an 8-byte signed integer, e.g. one with “%ld”, if LAMMPS was compiled with the -DLAMMPS_BIGBIG option for 8-byte IDs.
Note
Any value written to a text-based dump file that is a per-atom quantity calculated by a compute or fix is stored internally as a floating-point value. If the value is actually an integer and you wish it to appear in the text dump file as a (large) integer, then you need to use an appropriate format. For example, these commands:
compute 1 all property/local batom1 batom2
dump 1 all local 100 tmp.bonds index c_1[1] c_1[2]
dump_modify 1 format "%d %0.0f %0.0f"
will output the two atom IDs for atoms in each bond as integers. If the dump_modify command were omitted, they would appear as floating-point values, assuming they were large integers (more than 6 digits). The “index” keyword should use the “%d” format since it is not generated by a compute or fix, and is stored internally as an integer.
The fileper keyword is documented below with the nfile keyword.
The image keyword applies only to the dump atom style. If the image value is yes, 3 flags are appended to each atom’s coords which are the absolute box image of the atom in each dimension. For example, an x image flag of -2 with a normalized coord of 0.5 means the atom is in the center of the box, but has passed through the box boundary 2 times and is really 2 box lengths to the left of its current coordinate. Note that for dump style custom these various values can be printed in the dump file by using the appropriate atom attributes in the dump command itself.
The label keyword applies only to the dump local style. When it writes local information, such as bond or angle topology to a dump file, it will use the specified label to format the header. By default this includes 2 lines:
ITEM: NUMBER OF ENTRIES
ITEM: ENTRIES ...
The word “ENTRIES” will be replaced with the string specified, e.g. BONDS or ANGLES.
The maxfiles keyword can only be used when a ‘*’ wildcard is included in the dump file name, i.e. when writing a new file(s) for each snapshot. The specified Fmax is how many snapshots will be kept. Once this number is reached, the file(s) containing the oldest snapshot is deleted before a new dump file is written. If the specified Fmax <= 0, then all files are retained.
This can be useful for debugging, especially if you don’t know on what timestep something bad will happen, e.g. when LAMMPS will exit with an error. You can dump every timestep, and limit the number of dump files produced, even if you run for 1000s of steps.
The nfile or fileper keywords can be used in conjunction with the “%” wildcard character in the specified dump file name, for all dump styles except the dcd, image, movie, xtc, and xyz styles (for which “%” is not allowed). As explained on the dump command doc page, the “%” character causes the dump file to be written in pieces, one piece for each of P processors. By default P = the number of processors the simulation is running on. The nfile or fileper keyword can be used to set P to a smaller value, which can be more efficient when running on a large number of processors.
The nfile keyword sets P to the specified Nf value. For example, if Nf = 4, and the simulation is running on 100 processors, 4 files will be written, by processors 0,25,50,75. Each will collect information from itself and the next 24 processors and write it to a dump file.
For the fileper keyword, the specified value of Np means write one file for every Np processors. For example, if Np = 4, every 4th processor (0,4,8,12,etc) will collect information from itself and the next 3 processors and write it to a dump file.
The pad keyword only applies when the dump filename is specified with a wildcard “*” character which becomes the timestep. If pad is 0, which is the default, the timestep is converted into a string of unpadded length, e.g. 100 or 12000 or 2000000. When pad is specified with Nchar > 0, the string is padded with leading zeroes so they are all the same length = Nchar. For example, pad 7 would yield 0000100, 0012000, 2000000. This can be useful so that post-processing programs can easily read the files in ascending timestep order.
The pbc keyword applies to all the dump styles. As explained on the dump doc page, atom coordinates in a dump file may be slightly outside the simulation box. This is because periodic boundary conditions are enforced only on timesteps when neighbor lists are rebuilt, which will not typically coincide with the timesteps dump snapshots are written. If the setting of this keyword is set to yes, then all atoms will be remapped to the periodic box before the snapshot is written, then restored to their original position. If it is set to no they will not be. The no setting is the default because it requires no extra computation.
The precision keyword only applies to the dump xtc style. A specified value of N means that coordinates are stored to 1/N nanometer accuracy, e.g. for N = 1000, the coordinates are written to 1/1000 nanometer accuracy.
The refresh keyword only applies to the dump custom, cfg, image, and movie styles. It allows an “incremental” dump file to be written, by refreshing a compute that is used as a threshold for determining which atoms are included in a dump snapshot. The specified c_ID gives the ID of the compute. It is prefixed by “c_” to indicate a compute, which is the only current option. At some point, other options may be added, e.g. fixes or variables.
Note
This keyword can only be specified once for a dump. Refreshes of multiple computes cannot yet be performed.
The definition and motivation of an incremental dump file is as follows. Instead of outputting all atoms at each snapshot (with some associated values), you may only wish to output the subset of atoms with a value that has changed in some way compared to the value the last time that atom was output. In some scenarios this can result in a dramatically smaller dump file. If desired, by post-processing the sequence of snapshots, the values for all atoms at all timesteps can be inferred.
A concrete example is a simulation of atom diffusion in a solid, represented as atoms on a lattice. Diffusive hops are rare. Imagine that when a hop occurs an atom moves more than a distance Dhop. For any snapshot we only want to output atoms that have hopped since the last snapshot. This can be accomplished with something the following commands:
variable Dhop equal 0.6
variable check atom "c_dsp[4] > v_Dhop"
compute dsp all displace/atom refresh check
dump 1 all custom 20 tmp.dump id type x y z
dump_modify 1 append yes thresh c_dsp[4] > ${Dhop} refresh c_dsp The compute displace/atom command calculates the displacement of each atom from its reference position. The “4” index is the scalar displacement; 1,2,3 are the xyz components of the displacement. The dump_modify thresh command will cause only atoms that have displaced more than 0.6 Angstroms to be output on a given snapshot (assuming metal units). However, note that when an atom is output, we also need to update the reference position for that atom to its new coordinates. So that it will not be output in every snapshot thereafter. That reference position is stored by compute displace/atom. So the dump_modify refresh option triggers a call to compute displace/atom at the end of every dump to perform that update. The refresh check option shown as part of the compute displace/atom command enables the compute to respond to the call from the dump command, and update the appropriate reference positions. This is done be defining an atom-style variable, check in this example, which calculates a Boolean value (0 or 1) for each atom, based on the same criterion used by dump_modify thresh. See the compute displace/atom command for more details, including an example of how to produce output that includes an initial snapshot with the reference position of all atoms. Note that only computes with a refresh option will work with dump_modify refresh. See individual compute doc pages for details. Currently, only compute displace/atom supports this option. Others may be added at some point. If you use a compute that doesn’t support refresh operations, LAMMPS will not complain; dump_modify refresh will simply do nothing. The region keyword only applies to the dump custom, cfg, image, and movie styles. If specified, only atoms in the region will be written to the dump file or included in the image/movie. Only one region can be applied as a filter (the last one specified). See the region command for more details. Note that a region can be defined as the “inside” or “outside” of a geometric shape, and it can be the “union” or “intersection” of a series of simpler regions. The scale keyword applies only to the dump atom style. A scale value of yes means atom coords are written in normalized units from 0.0 to 1.0 in each box dimension. If the simulation box is triclinic (tilted), then all atom coords will still be between 0.0 and 1.0. A value of no means they are written in absolute distance units (e.g. Angstroms or sigma). The sfactor and tfactor keywords only apply to the dump xtc style. They allow customization of the unit conversion factors used when writing to XTC files. By default they are initialized for whatever units style is being used, to write out coordinates in nanometers and time in picoseconds. I.e. for real units, LAMMPS defines sfactor = 0.1 and tfactor = 0.001, since the Angstroms and fmsec used by real units are 0.1 nm and 0.001 psec respectively. If you are using a units system with distance and time units far from nm and psec, you may wish to write XTC files with different units, since the compression algorithm used in XTC files is most effective when the typical magnitude of position data is between 10.0 and 0.1. The sort keyword determines whether lines of per-atom output in a snapshot are sorted or not. A sort value of off means they will typically be written in indeterminate order, either in serial or parallel. This is the case even in serial if the atom_modify sort option is turned on, which it is by default, to improve performance. A sort value of id means sort the output by atom ID. A sort value of N or -N means sort the output by the value in the Nth column of per-atom info in either ascending or descending order. The dump local style cannot be sorted by atom ID, since there are typically multiple lines of output per atom. Some dump styles, such as dcd and xtc, require sorting by atom ID to format the output file correctly. If multiple processors are writing the dump file, via the “%” wildcard in the dump filename, then sorting cannot be performed. Note Unless it is required by the dump style, sorting dump file output requires extra overhead in terms of CPU and communication cost, as well as memory, versus unsorted output. The thermo keyword only applies the dump netcdf style. It triggers writing of thermo information to the dump file alongside per-atom data. The values included in the dump file are identical to the values specified by thermo_style. The thresh keyword only applies to the dump custom, cfg, image, and movie styles. Multiple thresholds can be specified. Specifying none turns off all threshold criteria. If thresholds are specified, only atoms whose attributes meet all the threshold criteria are written to the dump file or included in the image. The possible attributes that can be tested for are the same as those that can be specified in the dump custom command, with the exception of the element attribute, since it is not a numeric value. Note that a different attributes can be used than those output by the dump custom command. E.g. you can output the coordinates and stress of atoms whose energy is above some threshold. If an atom-style variable is used as the attribute, then it can produce continuous numeric values or effective Boolean 0/1 values which may be useful for the comparison operator. Boolean values can be generated by variable formulas that use comparison or Boolean math operators or special functions like gmask() and rmask() and grmask(). See the variable command doc page for details. The specified value must be a simple numeric value or the word LAST. If LAST is used, it refers to the value of the attribute the last time the dump command was invoked to produce a snapshot. This is a way to only dump atoms whose attribute has changed (or not changed). Three examples follow. dump_modify ... thresh ix != LAST This will dump atoms which have crossed the periodic x boundary of the simulation box since the last dump. (Note that atoms that crossed once and then crossed back between the two dump timesteps would not be included.) region foo sphere 10 20 10 15 variable inregion atom rmask(foo) dump_modify ... thresh v_inregion |^ LAST This will dump atoms which crossed the boundary of the spherical region since the last dump. variable charge atom "(q > 0.5) || (q < -0.5)" dump_modify ... thresh v_charge |^ LAST This will dump atoms whose charge has changed from an absolute value less than 1/2 to greater than 1/2 (or vice versa) since the last dump. E.g. due to reactions and subsequent charge equilibration in a reactive force field. The choice of operators listed above are the usual comparison operators. The XOR operation (exclusive or) is also included as “|^”. In this context, XOR means that if either the attribute or value is 0.0 and the other is non-zero, then the result is “true” and the threshold criterion is met. Otherwise it is not met. The time keyword only applies to the dump atom, custom, and local styles (and their COMPRESS package versions atom/gz, custom/gz and local/gz). If set to yes, each frame will will contain two extra lines before the “ITEM: TIMESTEP” entry: ITEM: TIME <elapsed time> This will output the current elapsed simulation time in current time units equivalent to the thermo keyword time. This is to simplify post-processing of trajectories using a variable time step, e.g. when using fix dt/reset. The default setting is no. The units keyword only applies to the dump atom, custom, and local styles (and their COMPRESS package versions atom/gz, custom/gz and local/gz). If set to yes, each individual dump file will contain two extra lines at the very beginning with: ITEM: UNITS <units style> This will output the current selected units style to the dump file and thus allows visualization and post-processing tools to determine the choice of units of the data in the dump file. The default setting is no. The unwrap keyword only applies to the dump dcd and xtc styles. If set to yes, coordinates will be written “unwrapped” by the image flags for each atom. Unwrapped means that if the atom has passed through a periodic boundary one or more times, the value is printed for what the coordinate would be if it had not been wrapped back into the periodic box. Note that these coordinates may thus be far outside the box size stored with the snapshot. These keywords apply only to the dump image and dump movie styles. Any keyword that affects an image, also affects a movie, since the movie is simply a collection of images. Some of the keywords only affect the dump movie style. The descriptions give details. The acolor keyword can be used with the dump image command, when its atom color setting is type, to set the color that atoms of each type will be drawn in the image. The specified type should be an integer from 1 to Ntypes = the number of atom types. A wildcard asterisk can be used in place of or in conjunction with the type argument to specify a range of atom types. This takes the form “*” or “*n” or “n*” or “m*n”. If N = the number of atom types, then an asterisk with no numeric values means all types from 1 to N. A leading asterisk means all types from 1 to n (inclusive). A trailing asterisk means all types from n to N (inclusive). A middle asterisk means all types from m to n (inclusive). The specified color can be a single color which is any of the 140 pre-defined colors (see below) or a color name defined by the dump_modify color option. Or it can be two or more colors separated by a “/” character, e.g. red/green/blue. In the former case, that color is assigned to all the specified atom types. In the latter case, the list of colors are assigned in a round-robin fashion to each of the specified atom types. The adiam keyword can be used with the dump image command, when its atom diameter setting is type, to set the size that atoms of each type will be drawn in the image. The specified type should be an integer from 1 to Ntypes. As with the acolor keyword, a wildcard asterisk can be used as part of the type argument to specify a range of atom types. The specified diam is the size in whatever distance units the input script is using, e.g. Angstroms. The amap keyword can be used with the dump image command, with its atom keyword, when its atom setting is an atom-attribute, to setup a color map. The color map is used to assign a specific RGB (red/green/blue) color value to an individual atom when it is drawn, based on the atom’s attribute, which is a numeric value, e.g. its x-component of velocity if the atom-attribute “vx” was specified. The basic idea of a color map is that the atom-attribute will be within a range of values, and that range is associated with a series of colors (e.g. red, blue, green). An atom’s specific value (vx = -3.2) can then mapped to the series of colors (e.g. halfway between red and blue), and a specific color is determined via an interpolation procedure. There are many possible options for the color map, enabled by the amap keyword. Here are the details. The lo and hi settings determine the range of values allowed for the atom attribute. If numeric values are used for lo and/or hi, then values that are lower/higher than that value are set to the value. I.e. the range is static. If lo is specified as min or hi as max then the range is dynamic, and the lower and/or upper bound will be calculated each time an image is drawn, based on the set of atoms being visualized. The style setting is two letters, such as “ca”. The first letter is either “c” for continuous, “d” for discrete, or “s” for sequential. The second letter is either “a” for absolute, or “f” for fractional. A continuous color map is one in which the color changes continuously from value to value within the range. A discrete color map is one in which discrete colors are assigned to sub-ranges of values within the range. A sequential color map is one in which discrete colors are assigned to a sequence of sub-ranges of values covering the entire range. An absolute color map is one in which the values to which colors are assigned are specified explicitly as values within the range. A fractional color map is one in which the values to which colors are assigned are specified as a fractional portion of the range. For example if the range is from -10.0 to 10.0, and the color red is to be assigned to atoms with a value of 5.0, then for an absolute color map the number 5.0 would be used. But for a fractional map, the number 0.75 would be used since 5.0 is 3/4 of the way from -10.0 to 10.0. The delta setting must be specified for all styles, but is only used for the sequential style; otherwise the value is ignored. It specifies the bin size to use within the range for assigning consecutive colors to. For example, if the range is from -10.0 to 10.0 and a delta of 1.0 is used, then 20 colors will be assigned to the range. The first will be from -10.0 <= color1 < -9.0, then 2nd from -9.0 <= color2 < -8.0, etc. The N setting is how many entries follow. The format of the entries depends on whether the color map style is continuous, discrete or sequential. In all cases the color setting can be any of the 140 pre-defined colors (see below) or a color name defined by the dump_modify color option. For continuous color maps, each entry has a value and a color. The value is either a number within the range of values or min or max. The value of the first entry must be min and the value of the last entry must be max. Any entries in between must have increasing values. Note that numeric values can be specified either as absolute numbers or as fractions (0.0 to 1.0) of the range, depending on the “a” or “f” in the style setting for the color map. Here is how the entries are used to determine the color of an individual atom, given the value X of its atom attribute. X will fall between 2 of the entry values. The color of the atom is linearly interpolated (in each of the RGB values) between the 2 colors associated with those entries. For example, if X = -5.0 and the 2 surrounding entries are “red” at -10.0 and “blue” at 0.0, then the atom’s color will be halfway between “red” and “blue”, which happens to be “purple”. For discrete color maps, each entry has a lo and hi value and a color. The lo and hi settings are either numbers within the range of values or lo can be min or hi can be max. The lo and hi settings of the last entry must be min and max. Other entries can have any lo and hi values and the sub-ranges of different values can overlap. Note that numeric lo and hi values can be specified either as absolute numbers or as fractions (0.0 to 1.0) of the range, depending on the “a” or “f” in the style setting for the color map. Here is how the entries are used to determine the color of an individual atom, given the value X of its atom attribute. The entries are scanned from first to last. The first time that lo <= X <= hi, X is assigned the color associated with that entry. You can think of the last entry as assigning a default color (since it will always be matched by X), and the earlier entries as colors that override the default. Also note that no interpolation of a color RGB is done. All atoms will be drawn with one of the colors in the list of entries. For sequential color maps, each entry has only a color. Here is how the entries are used to determine the color of an individual atom, given the value X of its atom attribute. The range is partitioned into N bins of width binsize. Thus X will fall in a specific bin from 1 to N, say the Mth bin. If it falls on a boundary between 2 bins, it is considered to be in the higher of the 2 bins. Each bin is assigned a color from the E entries. If E < N, then the colors are repeated. For example if 2 entries with colors red and green are specified, then the odd numbered bins will be red and the even bins green. The color of the atom is the color of its bin. Note that the sequential color map is really a shorthand way of defining a discrete color map without having to specify where all the bin boundaries are. Here is an example of using a sequential color map to color all the atoms in individual molecules with a different color. See the examples/pour/in.pour.2d.molecule input script for an example of how this is used. variable colors string & "red green blue yellow white & purple pink orange lime gray" variable mol atom mol%10 dump 1 all image 250 image.*.jpg v_mol type & zoom 1.6 adiam 1.5 dump_modify 1 pad 5 amap 0 10 sa 1 10${colors}
In this case, 10 colors are defined, and molecule IDs are mapped to one of the colors, even if there are 1000s of molecules.
The backcolor sets the background color of the images. The color name can be any of the 140 pre-defined colors (see below) or a color name defined by the dump_modify color option.
The bcolor keyword can be used with the dump image command, with its bond keyword, when its color setting is type, to set the color that bonds of each type will be drawn in the image.
The specified type should be an integer from 1 to Nbondtypes = the number of bond types. A wildcard asterisk can be used in place of or in conjunction with the type argument to specify a range of bond types. This takes the form “*” or “*n” or “n*” or “m*n”. If N = the number of bond types, then an asterisk with no numeric values means all types from 1 to N. A leading asterisk means all types from 1 to n (inclusive). A trailing asterisk means all types from n to N (inclusive). A middle asterisk means all types from m to n (inclusive).
The specified color can be a single color which is any of the 140 pre-defined colors (see below) or a color name defined by the dump_modify color option. Or it can be two or more colors separated by a “/” character, e.g. red/green/blue. In the former case, that color is assigned to all the specified bond types. In the latter case, the list of colors are assigned in a round-robin fashion to each of the specified bond types.
The bdiam keyword can be used with the dump image command, with its bond keyword, when its diam setting is type, to set the diameter that bonds of each type will be drawn in the image. The specified type should be an integer from 1 to Nbondtypes. As with the bcolor keyword, a wildcard asterisk can be used as part of the type argument to specify a range of bond types. The specified diam is the size in whatever distance units you are using, e.g. Angstroms.
The bitrate keyword can be used with the dump movie command to define the size of the resulting movie file and its quality via setting how many kbits per second are to be used for the movie file. Higher bitrates require less compression and will result in higher quality movies. The quality is also determined by the compression format and encoder. The default setting is 2000 kbit/s, which will result in average quality with older compression formats.
Note
Not all movie file formats supported by dump movie allow the bitrate to be set. If not, the setting is silently ignored.
The boxcolor keyword sets the color of the simulation box drawn around the atoms in each image as well as the color of processor sub-domain boundaries. See the “dump image box” command for how to specify that a box be drawn via the box keyword, and the sub-domain boundaries via the subbox keyword. The color name can be any of the 140 pre-defined colors (see below) or a color name defined by the dump_modify color option.
The color keyword allows definition of a new color name, in addition to the 140-predefined colors (see below), and associates 3 red/green/blue RGB values with that color name. The color name can then be used with any other dump_modify keyword that takes a color name as a value. The RGB values should each be floating point values between 0.0 and 1.0 inclusive.
When a color name is converted to RGB values, the user-defined color names are searched first, then the 140 pre-defined color names. This means you can also use the color keyword to overwrite one of the pre-defined color names with new RBG values.
The framerate keyword can be used with the dump movie command to define the duration of the resulting movie file. Movie files written by the dump movie command have a default frame rate of 24 frames per second and the images generated will be converted at that rate. Thus a sequence of 1000 dump images will result in a movie of about 42 seconds. To make a movie run longer you can either generate images more frequently or lower the frame rate. To speed a movie up, you can do the inverse. Using a frame rate higher than 24 is not recommended, as it will result in simply dropping the rendered images. It is more efficient to dump images less frequently.
none
## Default
The option defaults are
• append = no
• buffer = yes for dump styles atom, custom, loca, and xyz
• element = “C” for every atom type
• every = whatever it was set to via the dump command
• fileper = # of processors
• first = no
• flush = yes
• format = %d and %g for each integer or floating point value
• image = no
• label = ENTRIES
• maxfiles = -1
• nfile = 1
• pbc = no
• precision = 1000
• region = none
• scale = yes
• sort = off for dump styles atom, custom, cfg, and local
• sort = id for dump styles dcd, xtc, and xyz
• thresh = none
• units = no
• unwrap = no
• acolor = * red/green/blue/yellow/aqua/cyan
• amap = min max cf 0.0 2 min blue max red
• backcolor = black
• bcolor = * red/green/blue/yellow/aqua/cyan
• bdiam = * 0.5
• bitrate = 2000
• boxcolor = yellow
• color = 140 color names are pre-defined as listed below
• framerate = 24
These are the standard 109 element names that LAMMPS pre-defines for use with the dump image and dump_modify commands.
• 1-10 = “H”, “He”, “Li”, “Be”, “B”, “C”, “N”, “O”, “F”, “Ne”
• 11-20 = “Na”, “Mg”, “Al”, “Si”, “P”, “S”, “Cl”, “Ar”, “K”, “Ca”
• 21-30 = “Sc”, “Ti”, “V”, “Cr”, “Mn”, “Fe”, “Co”, “Ni”, “Cu”, “Zn”
• 31-40 = “Ga”, “Ge”, “As”, “Se”, “Br”, “Kr”, “Rb”, “Sr”, “Y”, “Zr”
• 41-50 = “Nb”, “Mo”, “Tc”, “Ru”, “Rh”, “Pd”, “Ag”, “Cd”, “In”, “Sn”
• 51-60 = “Sb”, “Te”, “I”, “Xe”, “Cs”, “Ba”, “La”, “Ce”, “Pr”, “Nd”
• 61-70 = “Pm”, “Sm”, “Eu”, “Gd”, “Tb”, “Dy”, “Ho”, “Er”, “Tm”, “Yb”
• 71-80 = “Lu”, “Hf”, “Ta”, “W”, “Re”, “Os”, “Ir”, “Pt”, “Au”, “Hg”
• 81-90 = “Tl”, “Pb”, “Bi”, “Po”, “At”, “Rn”, “Fr”, “Ra”, “Ac”, “Th”
• 91-100 = “Pa”, “U”, “Np”, “Pu”, “Am”, “Cm”, “Bk”, “Cf”, “Es”, “Fm”
• 101-109 = “Md”, “No”, “Lr”, “Rf”, “Db”, “Sg”, “Bh”, “Hs”, “Mt”
These are the 140 colors that LAMMPS pre-defines for use with the dump image and dump_modify commands. Additional colors can be defined with the dump_modify color command. The 3 numbers listed for each name are the RGB (red/green/blue) values. Divide each value by 255 to get the equivalent 0.0 to 1.0 value.
aliceblue = 240, 248, 255 antiquewhite = 250, 235, 215 aqua = 0, 255, 255 aquamarine = 127, 255, 212 azure = 240, 255, 255 beige = 245, 245, 220 bisque = 255, 228, 196 black = 0, 0, 0 blanchedalmond = 255, 255, 205 blue = 0, 0, 255 blueviolet = 138, 43, 226 brown = 165, 42, 42 burlywood = 222, 184, 135 cadetblue = 95, 158, 160 chartreuse = 127, 255, 0 chocolate = 210, 105, 30 coral = 255, 127, 80 cornflowerblue = 100, 149, 237 cornsilk = 255, 248, 220 crimson = 220, 20, 60 cyan = 0, 255, 255 darkblue = 0, 0, 139 darkcyan = 0, 139, 139 darkgoldenrod = 184, 134, 11 darkgray = 169, 169, 169 darkgreen = 0, 100, 0 darkkhaki = 189, 183, 107 darkmagenta = 139, 0, 139 darkolivegreen = 85, 107, 47 darkorange = 255, 140, 0 darkorchid = 153, 50, 204 darkred = 139, 0, 0 darksalmon = 233, 150, 122 darkseagreen = 143, 188, 143 darkslateblue = 72, 61, 139 darkslategray = 47, 79, 79 darkturquoise = 0, 206, 209 darkviolet = 148, 0, 211 deeppink = 255, 20, 147 deepskyblue = 0, 191, 255 dimgray = 105, 105, 105 dodgerblue = 30, 144, 255 firebrick = 178, 34, 34 floralwhite = 255, 250, 240 forestgreen = 34, 139, 34 fuchsia = 255, 0, 255 gainsboro = 220, 220, 220 ghostwhite = 248, 248, 255 gold = 255, 215, 0 goldenrod = 218, 165, 32 gray = 128, 128, 128 green = 0, 128, 0 greenyellow = 173, 255, 47 honeydew = 240, 255, 240 hotpink = 255, 105, 180 indianred = 205, 92, 92 indigo = 75, 0, 130 ivory = 255, 240, 240 khaki = 240, 230, 140 lavender = 230, 230, 250 lavenderblush = 255, 240, 245 lawngreen = 124, 252, 0 lemonchiffon = 255, 250, 205 lightblue = 173, 216, 230 lightcoral = 240, 128, 128 lightcyan = 224, 255, 255 lightgoldenrodyellow = 250, 250, 210 lightgreen = 144, 238, 144 lightgrey = 211, 211, 211 lightpink = 255, 182, 193 lightsalmon = 255, 160, 122 lightseagreen = 32, 178, 170 lightskyblue = 135, 206, 250 lightslategray = 119, 136, 153 lightsteelblue = 176, 196, 222 lightyellow = 255, 255, 224 lime = 0, 255, 0 limegreen = 50, 205, 50 linen = 250, 240, 230 magenta = 255, 0, 255 maroon = 128, 0, 0 mediumaquamarine = 102, 205, 170 mediumblue = 0, 0, 205 mediumorchid = 186, 85, 211 mediumpurple = 147, 112, 219 mediumseagreen = 60, 179, 113 mediumslateblue = 123, 104, 238 mediumspringgreen = 0, 250, 154 mediumturquoise = 72, 209, 204 mediumvioletred = 199, 21, 133 midnightblue = 25, 25, 112 mintcream = 245, 255, 250 mistyrose = 255, 228, 225 moccasin = 255, 228, 181 navajowhite = 255, 222, 173 navy = 0, 0, 128 oldlace = 253, 245, 230 olive = 128, 128, 0 olivedrab = 107, 142, 35 orange = 255, 165, 0 orangered = 255, 69, 0 orchid = 218, 112, 214 palegoldenrod = 238, 232, 170 palegreen = 152, 251, 152 paleturquoise = 175, 238, 238 palevioletred = 219, 112, 147 papayawhip = 255, 239, 213 peachpuff = 255, 239, 213 peru = 205, 133, 63 pink = 255, 192, 203 plum = 221, 160, 221 powderblue = 176, 224, 230 purple = 128, 0, 128 red = 255, 0, 0 rosybrown = 188, 143, 143 royalblue = 65, 105, 225 saddlebrown = 139, 69, 19 salmon = 250, 128, 114 sandybrown = 244, 164, 96 seagreen = 46, 139, 87 seashell = 255, 245, 238 sienna = 160, 82, 45 silver = 192, 192, 192 skyblue = 135, 206, 235 slateblue = 106, 90, 205 slategray = 112, 128, 144 snow = 255, 250, 250 springgreen = 0, 255, 127 steelblue = 70, 130, 180 tan = 210, 180, 140 teal = 0, 128, 128 thistle = 216, 191, 216 tomato = 253, 99, 71 turquoise = 64, 224, 208 violet = 238, 130, 238 wheat = 245, 222, 179 white = 255, 255, 255 whitesmoke = 245, 245, 245 yellow = 255, 255, 0 yellowgreen = 154, 205, 50
| 2019-11-19T08:31:37 |
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|
https://ikariam.fandom.com/wiki/Building:Town_wall
|
## FANDOM
1,797 Pages
Town wall
Function:
Increases the garrison limit
Requirements:
None
Expansion requirements:
Use requirements:
Must have at least 1 unit in town
## Description
The Town wall is a building that protects your citizens against your enemies and the sun. Beware! Enemies will try to tear holes in your wall or to climb over it. Every level increases the resistance of your Town wall.
## The Town wall in battle
When your city is attacked your wall is the first line of defense. Your wall occupies the front line of combat protecting your army and citizens until your opponent breaches the wall. While protected by the wall your Long-Range Fighter, Artillery, and Air units can engage the enemy. Your wall will also engage your enemies front line, with its own attacks.
All wall sections have their own Hit points , Attack points and Armor points .
1. Every time you increase your Wall's level, it will gain an additional 50 hit points as well as an additional armor points.
2. Your wall gains additional damage points per each level of increase. However, your wall will make significant gains in its damage points at levels 10 and 20.
3. Your wall's accuracy will increase at levels 10 and 20 only.
As your enemy breaches a wall by doing enough damage to a section, your front line will fill in with heavy infantry. Once the entire wall is breached, flankers will engage each other. In the case that one side has no flankers or all flankers have been killed, the other side's flankers will now be able to slaughter the enemy's long-range fighter and then artillery. The number of sections of your wall is determined by the size of your Town hall.
• If a city has no units capable of filling in the front line, heavy infantry, light infantry, or long-ranged fighters, stationed in it when it is attacked or they have all died and the wall is still whole then the attacking army can pillage or occupy the town as soon as they create a single breach in the wall.
## Garrison limit
The Town wall contributes to your Land Garrison Limit.
Every level of the Town wall provides +50 spaces for your land units.
## Expansion Details
The time (in seconds) it takes to upgrade to the next level is determined by the following formula: ${ \text{Building time (seconds)} = \left \lbrack \cfrac{57,600}{11} \times 1.1^\text{Level} - 3,240\right \rbrack }$
Level 1 does not follow this formula, as its build time was shortened by 40 minutes 30 seconds (2,430s)
when it was added to the in-game tutorial.
The accumulative time (in seconds) it takes to upgrade up to the next level is determined by the following formula: ${ \text{Accumulative building time (seconds)} = \left \lbrack 57,600 \times \left (\ 1.1^\text{Level} -\ 1\ \right ) - 3,240 \times \text{Level}\right \rbrack - 2,430}$
Level 1 does follow this formula.
Due to the large number of templates used to display the information on this building, we are breaking this building's expansion levels down into groups of 8, instead of the normal grouping of 10.
## Other Standard Buildings
Community content is available under CC-BY-SA unless otherwise noted.
| 2020-04-04T03:30:51 |
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|
http://mathonline.wikidot.com/the-curl-of-a-vector-field-examples-1
|
The Curl of a Vector Field Examples 1
Table of Contents
The Curl of a Vector Field Examples 1
Recall from The Curl of a Vector Field page that if $\mathbf{F} (x, y, z) = P(x, y, z) \vec{i} + Q(x, y, z) \vec{j} + R(x, y, z) \vec{k}$ is a vector field on $\mathbb{R}^3$ and the appropriate partial derivatives of $P$, $Q$, and $R$ exist then the curl of $\mathbf{F}$ is given by the following formula:
(1)
\begin{align} \quad \mathrm{curl} ( \mathbf{F}) = \nabla \times \mathbf{F} = \left ( \frac{\partial R}{\partial y} - \frac{\partial Q}{\partial z} \right ) \vec{i} + \left ( \frac{\partial P}{\partial z} - \frac{\partial R}{\partial x} \right ) \vec{j} + \left ( \frac{\partial Q}{\partial x} - \frac{\partial P}{\partial y} \right ) \vec{k} \end{align}
We will now look at some examples of computing the curl of a vector field.
Example 1
Compute the curl of the vector field $\mathbf{F} (1 + y + z^2) \vec{i} + e^{xyz} \vec{j} + (xyz) \vec{k}$.
Applying the formula for the curl of $\mathbf{F}$ directly and we have that:
(2)
\begin{align} \quad \quad \mathrm{curl} ( \mathbf{F}) = \nabla \times \mathbf{F} = \left ( \frac{\partial}{\partial y} (xyz) - \frac{\partial}{\partial z} (e^{xyz}) \right ) \vec{i} + \left ( \frac{\partial}{\partial z} (1 + y + z^2) - \frac{\partial}{\partial x} (xyz) \right ) \vec{j} + \left ( \frac{\partial}{\partial x} (e^{xyz}) - \frac{\partial}{\partial y} (1 + y + z^2) \right ) \vec{k} \\ \quad \quad \mathrm{curl} ( \mathbf{F} ) = \left ( xz -xye^{xyz} \right ) \vec{i} + \left (2z - yz \right ) \vec{k} + \left ( yze^{xyz} - 1 \right ) \vec{k} \end{align}
Example 2
Compute the curl of the vector field $\mathbf{F}(x, y, z) = \frac{2xy}{z} \vec{i} + xe^{xy} \vec{j} + \cos (xy^2) \vec{k}$.
Applying the formula for the curl of $\mathbf{F}$ directly and we have that:
(3)
\begin{align} \quad \quad \mathrm{curl} ( \mathbf{F}) = \nabla \times \mathbf{F} = \left ( \frac{\partial}{\partial y} (\cos (xy^2) ) - \frac{\partial}{\partial z} (xe^{xy}) \right ) \vec{i} + \left ( \frac{\partial}{\partial z} \left (\frac{2xy}{z} \right ) - \frac{\partial}{\partial x} (\cos (xy^2)) \right ) \vec{j} + \left ( \frac{\partial}{\partial x} (xe^{xy}) - \frac{\partial}{\partial y} \left (\frac{2xy}{z} \right ) \right ) \vec{k} \\ \quad \quad \mathrm{curl} (\mathbf{F}) = \left ( -2xy \sin (xy^2) - 0 \right ) \vec{i} + \left (-\frac{2xy}{z^2} + y^2 \sin (xy^2) \right ) \vec{j} + \left (xye^{xy} + e^{xy} - \frac{2x}{z} \right ) \vec{k} \end{align}
Example 3
Compute the curl of the vector field $\mathbf{F} (x, y, z) = \log (xy) \vec{i} + \sec (xy) \vec{j} + \frac{3}{x^2} \vec{k}$. Are there any points in $\mathbb{R}^3$ for which $\mathbf{F}$ irrotational?
Applying the formula for the curl of $\mathbf{F}$ directly and we have that:
(4)
\begin{align} \quad \quad \mathrm{curl} ( \mathbf{F}) = \nabla \times \mathbf{F} = \left ( \frac{\partial}{\partial y} \left ( \frac{3}{x^2} \right ) - \frac{\partial}{\partial z} (\sec (xy)) \right ) \vec{i} + \left ( \frac{\partial}{\partial z} (\log (xy)) - \frac{\partial}{\partial x} \left ( \frac{3}{x^2} \right) \right ) \vec{j} + \left ( \frac{\partial}{\partial x} (\sec (xy)) - \frac{\partial}{\partial y} \log (xy) \right ) \vec{k} \\ \quad \quad \mathrm{curl} (\mathbf{F}) = \left ( 0 - 0 \right ) \vec{i} + \left ( 0 + \frac{6}{x^3} \right ) \vec{j} + \left ( y \sec (xy) \tan (xy) - \frac{1}{y \ln (10)} \right ) \vec{k} = 0 \vec{i} + \frac{6}{x^3} \vec{k} + \left ( y \sec (xy) \tan (xy) - \frac{1}{y \ln (10)} \right ) \vec{k} \end{align}
Now $\mathbf{F}$ is irrotational if $\mathrm{curl} (\mathbf{F}) = \vec{0}$ which implies that we must have:
(5)
\begin{align} \left\{\begin{matrix} 0 = 0\\ \frac{6}{x^3} = 0\\ y \sec (xy) \tan (xy) - \frac{1}{y \ln (10)} =0 \end{matrix}\right. \end{align}
However, note that $\frac{6}{x^3} \neq 0$ for all $(x, y, z) \in \mathbb{R}^3$, so $\mathbf{F}$ is not irrotational anywhere.
Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License
| 2019-04-20T08:44:52 |
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|
http://www.free-photos.biz/photographs/business/documents/178842_half-president-system.php
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## Summary
Description ???(??)?: ??File:Half-president-system.jpg???????? English: Vector image according of File:Half-president-system.jpg Date 1 July 2009 Source Own work Author Albuseer
This vector image was created with MetaPost. For MetaPost source code please see below.
## Source
Source (MetaPost):
Filename:hps.mp
verbatimtex
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The following command are used to convent it to SVG:
mptopdf hps.mp
pdf2svg hps-1.pdf Half-president-system-hant.svg
For execute the command, you need to install texlive and pdf2svg
## Licensing
I, the copyright holder of this work, hereby publish it under the following licenses:
This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. You are free: to share – to copy, distribute and transmit the work to remix – to adapt the work Under the following conditions: attribution – You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). share alike – If you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.
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Licensing:
Creative Commons Attribution-Share Alike 3.0 Unported
| 2017-03-25T02:13:10 |
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http://dlmf.nist.gov/17.6
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# §17.6 Function
## §17.6(iv) Differential Equations
### ¶ -Differential Equation
(17.6.27) reduces to the hypergeometric equation (15.10.1) with the substitutions , , , followed by .
## §17.6(v) Integral Representations
where , , and the contour of integration separates the poles of from those of , and the infimum of the distances of the poles from the contour is positive.
## §17.6(vi) Continued Fractions
For continued-fraction representations of the function, see Cuyt et al. (2008, pp. 395–399).
| 2013-05-21T13:28:40 |
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https://pos.sissa.it/301/396/
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Volume 301 - 35th International Cosmic Ray Conference (ICRC2017) - Session Cosmic-Ray Indirect. CRI-instrumentation EAS
An improved reconstruction method for the AMIGA detectors
M.J. Figueira* on behalf of the Pierre Auger Collaboration
*corresponding author
Full text: pdf
Pre-published on: August 16, 2017
Published on: August 03, 2018
Abstract
The Auger Muon and Infill Ground Array (AMIGA) is a muon detector that is currently being built as part of AugerPrime, the upgrade of the Pierre Auger Observatory. It consists of 30 m$^2$ plastic scintillator counters buried 2.3 m underground and water-Cherenkov detectors at the surface, organized in a periodic 750 m triangular array, and deployed over an area of 23.5 km$^2$. Each counter is composed of three 10 m$^2$ modules segmented into 64 scintillator strips. Two positions of the engineering array were further equipped with "twin" detectors to assess reconstruction uncertainties. AMIGA allows for direct measurement of the muon content of air showers with primary energies above 10$^{17}$ eV. In this work, the detector reconstruction strategy is revisited and the bias induced by particles traversing two adjacent strips, the so-called corner-clipping effect, is thoroughly analyzed. A bias correction based on end-to-end simulations of both the air showers and the detector response is presented. The improved reconstruction method was applied to experimental data acquired by the AMIGA engineering array, and preliminary results of the muon content estimator $\rho_{450}$ (muon density 450 m from the shower axis) are presented.
DOI: https://doi.org/10.22323/1.301.0396
How to cite
Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in "proceeding" format which is more detailed and complete.
Open Access
Copyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
| 2020-12-04T02:43:23 |
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http://www.compchemhighlights.org/2014_07_01_archive.html
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## Tuesday, July 29, 2014
### Protein structure prediction from sequence variation
Debora S. Marks, Thomas A. Hopf and Chris Sander Nature Biotechnology 2012, 30, 1072
Contributed by +Jan Jensen
This perspective paper gives a great overview of a very new and very promising sub-field of computational protein structure determination that started with this 2011 paper (see also this interesting blogpost). The method predicts distance restraints between two amino acids by looking for correlated changes in the protein sequence. These distance restraints are then used to determine 3D protein structures using the same software package used to compute NMR structures using NOE constraints.
The method has been tested on globular and membrane proteins up to 258 and 483 amino acids, respectively. About 0.5 to 0.75 predicted constraints per residue is needed and ca 5$L$ (where $L$ is the number of amino acids) diverse sequences are needed to produce reasonable protein structures with $C_\alpha$ RMSDs < 5 Å relative to the corresponding x-ray structures.
A $C_\alpha$ RMSD of 5 Å may sounds like a lot but active site geometries may be significantly more accurate due to "strong evolutionary constraints". For example while the structure of trypsin was predicted with a $C_\alpha$ RMSD of 4.3 Å, the relative orientation of the catalytic triad was predicted with a $C_\alpha$ RMSD of only 0.6 Å (1.3 Å all atom-RMSD).
Furthermore, x-ray structures are often refined using, for example, MD simulations before they are used in computational studies. I would be very interesting to compare computational predictions (e.g. activation energies, pKa values of active site residues, or docking scores) based on x-ray structures and evolutionary constraints, i.e. to compare their chemical accuracy.
The number of available sequences is growing very quickly, so I believe the main general issue that must be addressed with this method is the efficient prediction of structures of globular proteins larger than ca 400 amino acids using distance restraints. This is still quite a demanding task.
The authors provide a very nice web-service for the prediction of contacts and structures, which I have used in my own research.
In conclusion, this method provides a very nice complement to homology modeling for cases where no close structural homologs, but many sequence homologues, are available. Given the pace with which new sequences are determined it won't be too many years before a reasonable protein structure can be predicted for the vast majority of cases.
This work is licensed under a Creative Commons Attribution 4.0 International License.
## Friday, July 25, 2014
### Local hyperdynamics
Soo Young Kim, Danny Perez and Arthur F. Voter J. Chem. Phys. 139, 144110 (2013)
Contributed by David Bowler
Reposted from Atomistic Computer Simulations with permission
One of the key desires in atomistic simulations of all kinds, whether chemistry, biology, physics, materials science or earth sciences, is to be able to model accurately the long-time evolution of large systems. There have been good advances in recent years in linear scaling approaches to DFT and quantum chemistry[1], and significant progress in time acceleration (e.g. metadynamics[2] and hyperdynamics[3]).
The paper I will discuss here[4] points to a way to combine these two efforts, so that significant time acceleration can be applied to large systems. In combination with linear scaling electronic structure methods, this will allow us to achieve linear scaling in both size and time. The method, local hyperdynamics (LHD), is a development of the original hyperdynamics (HD) method, which is designed to increase the rate at which a system escapes from energy valleys. The idea behind HD is fairly simple, though elegant: a boost potential is added to the energy surface of the system being modelled so as to raise the bottom of the valleys in the system. This boost potential must go to zero if the system approaches a transition state; this requirement ensures that the rates of escape are not changed relative to each other, but leads to poor scaling with system size. As a larger system is modelled, it is more likely that a transition state will be found in some part of the system, and the boost becomes zero more and more of the time. The boosted time or hypertime can be evaluated during the simulation and related to the true system dynamics.
LHD defines local regions (centred normally on bonds) within which a local boost is applied. This allows the dynamics of the entire system to be boosted, and as the regions are independent, when one region goes through a transition, the other regions will not be affected. As the boost is only local, the dynamics are no longer conservative, though the authors make good arguments to suggest that, on average, using a Langevin thermostat, dynamics which are very close to conservative are followed.
The regions need to be large enough to encompass the characteristic length-scale of interactions and transitions being modelled, otherwise there will may be incorrect boosts from neighbouring domains. Once the system size is larger than the region size, the authors demonstrate that the boost factor achieved is constant with system size.
As each region has its own boost factor, some care has to be applied to ensure that boosting is uniform throughout the system. Given a target boost factor, the local boosting can be monitored and adjusted to ensure that it matches the target on average. The authors suggest that this time-evolving correction to the boost should be called a boostostat. There are careful, detailed statistical arguments which are worth careful reading in the paper.
The paper is also extremely careful in exploring the effects of the assumptions imposed. There will be force mismatches at the region edges, along with the lack of conservative dynamics. However, plausible arguments are made that these should average out for relatively uniform systems. A challenging system such as water, which contains both weak and strong bonds, might well show more significant deviation from these assumptions.
The authors tested the method with an embedded atom method (EAM) for Ag(100) with adatoms, vacancies and steps, and show excellent agreement with normal MD. For rare events, they show that boost of 10^6 are possible and give good agreement with transition state theory, though normally they work on boost factors around 100.
The Conquest developers (of which I am one) have recently performed full DFT molecular dynamics on 32,768 atoms for 2ps, and static calculations on over 1,000,000 atoms; in combination with LHD, we can see that DFT MD should be possible on 100,000+ atoms for nanoseconds and beyond.
[1] Rep. Prog. Phys. 75 036503 (2012) DOI:10.1088/0034-4885/75/3/036503
[2] Rep. Prog. Phys. 71, 126601 (2008) DOI:10.1088/0034-4885/71/12/126601
[3] Phys. Rev. Lett., 78, 3908(1997) DOI:10.1103/PhysRevLett.78.3908
[4] J. Chem. Phys., 139, 144110 (2013) DOI:10.1063/1.4824389
## Wednesday, July 23, 2014
### Dearomatization-Induced Transannular Cyclization: Synthesis of Electron-Accepting Thiophene-S,S-Dioxide-Fused Biphenylene
Fukazawa, A.; Oshima, H.; Shimizu, S.; Kobayashi, N.; Yamaguchi, S. J. Am. Chem. Soc. 2014, 136, 8738-8745
Contributed by Steven Bachrach.
Reposted from Computational Organic Chemistry with permission
Aromaticity and orbital symmetry rules, though seemingly of ancient origin, remain areas of active interest. This paper by Fukazawa, et al combine both issues.1 The multiple-step electrocyclization of 1gives 2 in a reaction that takes 9 days at 80 °C. What would be the effect of diminishing the aromatic character of the fused rings of 1? Would the reaction be faster or slower?
Before discussing the experimental results, let’s examine the B3LYP/6-31G(d) results for the reaction of1’3 and 5. (Note that a slightly smaller pendant substituent is used in the computations than in the experiment.) The optimized geometries of the critical points along the reaction pathway for the cyclization of 3 are shown in Figure 1.
3(0.0) 3-TS1(17.9) 3-INT(10.4) 3-TS2(13.3) 4(-60.7)
Figure 1. B3LYP/6-31G(d) optimized geometries and relative energies (kcal mol-1) for the critical points along the reaction 3 → 4.
Remember that all structures on my blog can be viewed interactively by clicking on the image of the molecule.
For 1’, the first barrier (for the 8π cyclization) has a barrier of about 23 kcal mol-1, but the second step (the 4π cyclization) has an even larger barrier of 28 kcal mol-1. However, reducing the aromaticity of one of the fused rings (compound 3) leads to lower barriers of 18 and 13 kcal mol-1. For the cyclization of 5, only a single transition state was found – no intermediate and no second TS – with a barrier of 12 kcal mol-1. Thus, removing these external aromatic rings reduces the barrier of the reaction, and that is exactly what is found experimentally!
### References
(1) Fukazawa, A.; Oshima, H.; Shimizu, S.; Kobayashi, N.; Yamaguchi, S. "Dearomatization-Induced Transannular Cyclization: Synthesis of Electron-Accepting Thiophene-S,S-Dioxide-Fused Biphenylene," J. Am. Chem. Soc. 2014136, 8738-8745, DOI: 10.1021/ja503499n.
### InChIs:
1: InChI=1S/C44H64S4Si4/c1-41(2,3)49(13,14)37-25-29-30-26-38(50(15,16)42(4,5)6)46-34(30)23-24-36-32(28-40(48-36)52(19,20)44(10,11)12)31-27-39(51(17,18)43(7,8)9)47-35(31)22-21-33(29)45-37/h25-28H,1-20H3/b30-29-,32-31-
InChIKey=OCNQBMWQONUVNH-IOYDOZLVSA-N
1’:InChI=1S/C32H40S4Si4/c1-37(2,3)29-17-21-22-18-30(38(4,5)6)34-26(22)15-16-28-24(20-32(36-28)40(10,11)12)23-19-31(39(7,8)9)35-27(23)14-13-25(21)33-29/h17-20H,1-12H3/b22-21-,24-23-
InChIKey=GTFPBRMBCLREPG-ICHHBZPXSA-N
2: InChI=1S/C44H64S4Si4/c1-41(2,3)49(13,14)29-21-25-26-22-30(50(15,16)42(4,5)6)46-38(26)34-33(37(25)45-29)35-36(34)40-28(24-32(48-40)52(19,20)44(10,11)12)27-23-31(47-39(27)35)51(17,18)43(7,8)9/h21-24H,1-20H3
InChIKey=OTDXAOVIIQYYNV-UHFFFAOYSA-N
2’: InChI=1S/C32H40S4Si4/c1-37(2,3)21-13-17-18-14-22(38(4,5)6)34-30(18)26-25(29(17)33-21)27-28(26)32-20(16-24(36-32)40(10,11)12)19-15-23(35-31(19)27)39(7,8)9/h13-16H,1-12H3
InChIKey=IYZNCPPDTHWWCO-UHFFFAOYSA-N
3: InChI=1S/C32H40O2S4Si4/c1-39(2,3)29-17-21-22-18-30(40(4,5)6)37-27(22)15-16-28-24(20-32(38(28,33)34)42(10,11)12)23-19-31(41(7,8)9)36-26(23)14-13-25(21)35-29/h17-20H,1-12H3/b22-21-,24-23-
InChIKey=ZJBDGDJVLGNVOD-ICHHBZPXSA-N
4: InChI=1S/C32H40O2S4Si4/c1-39(2,3)21-13-17-18-14-22(40(4,5)6)36-30(18)26-25(29(17)35-21)27-28(26)32-20(16-24(38(32,33)34)42(10,11)12)19-15-23(37-31(19)27)41(7,8)9/h13-16H,1-12H3
InChIKey=QUSJUOMZBJUGON-UHFFFAOYSA-N
5: InChI=1S/C32H40O8S4Si4/c1-45(2,3)29-17-21-22-18-30(46(4,5)6)42(35,36)26(22)15-16-28-24(20-32(44(28,39)40)48(10,11)12)23-19-31(47(7,8)9)43(37,38)27(23)14-13-25(21)41(29,33)34/h17-20H,1-12H3/b22-21-,24-23-
InChIKey=NNZTUSIYEPMHMP-ICHHBZPXSA-N
6: InChI=1S/C32H40O8S4Si4/c1-45(2,3)21-13-17-18-14-22(46(4,5)6)42(35,36)30(18)26-25(29(17)41(21,33)34)27-28(26)32-20(16-24(44(32,39)40)48(10,11)12)19-15-23(47(7,8)9)43(37,38)31(19)27/h13-16H,1-12H3
InChIKey=JZHQQYXUIQXWLQ-UHFFFAOYSA-N
This work is licensed under a Creative Commons Attribution-NoDerivs 3.0 Unported License.
## Friday, July 11, 2014
### Error Estimates for Solid-State Density-Functional Theory Predictions: An Overview by Means of the Ground-State Elemental Crystals
K. Lejaeghere, V. Van Speybroeck, G. Van Oost & S. Cottenier Critical Reviews in Solid State and Materials Sciences 2014, 39, 1-24
Contributed by David Bowler
Reposted from Atomistic Computer Simulations with permission
The question of how to characterise the accuracy of a computer code is a difficult one, and I have touched on these issues before (here, here and here for instance). However, given the large number of codes available, it should be possible to compare them to each other and to experiment (or higher level calculations) to test them. This is a well-established process in the quantum chemistry community, where there are various test sets for different properties, including enthalpies of formation(G97/2)[1], weak bonding (S22)[2] (and a vast database of different properties[3]).
A recent paper[4] and associated web site[5] offers a first approach for solid state codes, with the comparison based on the differences between all-electron and pseudopotential calculations. The presumption here is that all-electron calculations are the touchstone (though the website notes that the all-electron results have been refined to use extremely accurate tolerances and small muffin-tin radii, so there is clearly room for improvement in any method).
The idea of the comparison is to calculate binding energy curves for most elements in the periodic table, and from these curves to derive a single number which characterises the deviation from all-electron results. The deviation per element can be viewed, as can the deviation from experiment for the all-electron calculations. The deviation, delta, is defined by an integral over all calculated values of volume, and thus includes implicitly both the lattice constant and the bulk modulus, though not the cohesive energy. Most results shown on the website are for plane-wave codes, which generally perform rather well (the old norm-conserving FHI pseudopotentials are less accurate, though, and should be treated with care).
The approach is a good one, though a little heavy on the tester, and scripts to perform the necessary calculations are made freely available. However, the choice of the elemental form makes the tests rather restricted: there is no way to examine different types of bonding or different oxidation state, for instance. It is quite easy to imagine developing a set of these test suites for different purposes in solid state codes, just as there are different test sets in quantum chemistry.
The accuracy tests seem to be most illuminating for the pseudopotentials, rather than the codes themselves, and I think that it would be of immense value to the community if the pseudopotential generation details were made available. This should not just include the core radii and the reference configurations, but also a clear description of the pseudopotential algorithm (or an appropriate reference along with details).
There is something of a danger of using codes and supplied pseudopotential libraries as black boxes: there is a need to test parameters, though it’s rare (and I am happy to acknowledge that I don’t do it as much as I should). This paper and associated developments should go some way to standardising plane wave codes, and giving quantitative information on their reliability.
Note As I was writing this, a new paper in Science has just been published which takes a different view, and compares results from different functionals; it’s worth a read[6]
[1] J. Chem. Phys. 106, 1063 (1997) DOI:10.1063/1.473182
[2] Phys. Chem. Chem. Phys. 8, 1985 (2006) DOI: 10.1039/B600027D
[3] http://t1.chem.umn.edu/db/ and see arXiv http://arxiv.org/abs/1212.0944
[4] Crit. Rev. Sol. Stat. Mat. Sci. 39, 1–24. DOI:10.1080/10408436.2013.772503
[5] http://molmod.ugent.be/deltacodesdft
[6] Science 345, 197 (2014) DOI:10.1126/science.1253486
### Synthesis, Characterization, and Properties of [4]Cyclo-2,7-pyrenylene: Effects of Cyclic Structure on the Electronic Properties of Pyrene Oligomers
Iwamoto, T.; Kayahara, E.; Yasuda, N.; Suzuki, T.; Yamago, S. Angew. Chem. Int. Ed. 2014, 53, 6430-6434
Contributed by Steven Bachrach.
Reposted from Computational Organic Chemistry with permission
Macrocycles composed of aromatic subunits, like polycycloparaphenylenes, are of interest as components of nanotubes and for possible interesting optical properties. Tremendous advances have occurred over the past decade in preparing these rings ; see for examples these posts. Yamago now reports on the synthesis, optical properties and structure of [4]cyclo-2,7-pyrenylene 1, made by joining four pyrene units together.1
B3LYP/6-31G(d) optimization of the structure of 1 reveals a D2 geometry (Figure 1). This structure shows a very distorted pyrene unit. The strain energy of 1 is estimated as 392 kJ mol-1 (though how this was arrived at is not mentioned!), which is much larger than the strain energy of [8]-cycloparaphenylene.
Figure 1. B3LYP/6-31G(d) optimized structure of 1
This is another molecule to be sure to click on and rotate using JMol.
The nature of the HOMO and LUMO of 1 is very different than that of linear tetra-2,7-pyrene. The degenerate HOMOs and degenerate LUMOs of the linear compound have a node at the 2 and 7 positions and are localized to the terminal and central pyrene units, respectively. The HOMO and LUMO of 1 are fully delocalized. The implications of this are seen in the spectroscopy and electrochemistry of 1.
### References
(1) Iwamoto, T.; Kayahara, E.; Yasuda, N.; Suzuki, T.; Yamago, S. "Synthesis, Characterization, and Properties of [4]Cyclo-2,7-pyrenylene: Effects of Cyclic Structure on the Electronic Properties of Pyrene Oligomers," Angew. Chem. Int. Ed. 201453, 6430-6434, DOI:http://dx.doi.org/10.1002/anie.201403624.
### InChIs
1: InChI=1S/C64H32/c1-2-34-18-50-20-36-4-3-35-19-49(17-33(1)57(35)58(34)36)51-21-37-5-7-41-25-53(26-42-8-6-38(22-51)59(37)61(41)42)55-29-45-13-15-47-31-56(32-48-16-14-46(30-55)63(45)64(47)48)54-27-43-11-9-39-23-52(50)24-40-10-12-44(28-54)62(43)60(39)40/h1-32H/b51-49-,52-50-,55-53-,56-54-
InChIKey=AWPUJIHMRRFHHU-GYSOBDCPSA-N
This work is licensed under a Creative Commons Attribution-NoDerivs 3.0 Unported License.
| 2018-07-16T05:00:00 |
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|
http://zims-en.kiwix.campusafrica.gos.orange.com/wikipedia_en_all_nopic/A/Hamming_distance
|
# Hamming distance
In information theory, the Hamming distance between two strings of equal length is the number of positions at which the corresponding symbols are different. In other words, it measures the minimum number of substitutions required to change one string into the other, or the minimum number of errors that could have transformed one string into the other. In a more general context, the Hamming distance is one of several string metrics for measuring the edit distance between two sequences. It is named after the American mathematician Richard Hamming.
3-bit binary cube for finding Hamming distance
Two example distances: 100→011 has distance 3; 010→111 has distance 2
The minimum distance between any two vertices is the Hamming distance between the two binary strings.
4-bit binary tesseract for finding Hamming distance.
Two example distances: 0100→1001 has distance 3; 0110→1110 has distance 1
A major application is in coding theory, more specifically to block codes, in which the equal-length strings are vectors over a finite field.
## Examples
The Hamming distance between:
• "karolin" and "kathrin" is 3.
• "karolin" and "kerstin" is 3.
• 1011101 and 1001001 is 2.
• 2173896 and 2233796 is 3.
## Properties
For a fixed length n, the Hamming distance is a metric on the set of the words of length n (also known as a Hamming space), as it fulfills the conditions of non-negativity, identity of indiscernibles and symmetry, and it can be shown by complete induction that it satisfies the triangle inequality as well.[1] The Hamming distance between two words a and b can also be seen as the Hamming weight of a b for an appropriate choice of the operator, much as the difference between two integers can be seen as a distance from zero on the number line.
For binary strings a and b the Hamming distance is equal to the number of ones (population count) in a XOR b.[2] The metric space of length-n binary strings, with the Hamming distance, is known as the Hamming cube; it is equivalent as a metric space to the set of distances between vertices in a hypercube graph. One can also view a binary string of length n as a vector in ${\displaystyle \mathbb {R} ^{n}}$ by treating each symbol in the string as a real coordinate; with this embedding, the strings form the vertices of an n-dimensional hypercube, and the Hamming distance of the strings is equivalent to the Manhattan distance between the vertices.
## Error detection and error correction
The minimum Hamming distance is used to define some essential notions in coding theory, such as error detecting and error correcting codes. In particular, a code C is said to be k error detecting if, and only if, the minimum Hamming distance between any two of its codewords is at least k+1.[1]
A code C is said to be k-errors correcting if, for every word w in the underlying Hamming space H, there exists at most one codeword c (from C) such that the Hamming distance between w and c is at most k. In other words, a code is k-errors correcting if, and only if, the minimum Hamming distance between any two of its codewords is at least 2k+1. This is more easily understood geometrically as any closed balls of radius k centered on distinct codewords being disjoint.[1] These balls are also called Hamming spheres in this context.[3]
Thus a code with minimum Hamming distance d between its codewords can detect at most d-1 errors and can correct ⌊(d-1)/2⌋ errors.[1] The latter number is also called the packing radius or the error-correcting capability of the code.[3]
## History and applications
The Hamming distance is named after Richard Hamming, who introduced the concept in his fundamental paper on Hamming codes Error detecting and error correcting codes in 1950.[4] Hamming weight analysis of bits is used in several disciplines including information theory, coding theory, and cryptography.
It is used in telecommunication to count the number of flipped bits in a fixed-length binary word as an estimate of error, and therefore is sometimes called the signal distance.[5] For q-ary strings over an alphabet of size q 2 the Hamming distance is applied in case of the q-ary symmetric channel, while the Lee distance is used for phase-shift keying or more generally channels susceptible to synchronization errors because the Lee distance accounts for errors of ±1.[6] If ${\displaystyle q=2}$ or ${\displaystyle q=3}$ both distances coincide because any pair of elements from ${\textstyle \mathbb {Z} /2\mathbb {Z} }$ or ${\textstyle \mathbb {Z} /3\mathbb {Z} }$ differ by 1, but the distances are different for larger ${\displaystyle q}$.
The Hamming distance is also used in systematics as a measure of genetic distance.[7]
However, for comparing strings of different lengths, or strings where not just substitutions but also insertions or deletions have to be expected, a more sophisticated metric like the Levenshtein distance is more appropriate.
In processor interconnects, the dynamic energy consumption depends on the number of transitions. With level-signaling scheme, the number of transitions depends on Hamming distance between consecutively transmitted buses.[8] Hence, by reducing this Hamming distance, the data-movement energy can be reduced.
## Algorithm example
The function `hamming_distance()`, implemented in Python 2.3+, computes the Hamming distance between two strings (or other iterable objects) of equal length by creating a sequence of Boolean values indicating mismatches and matches between corresponding positions in the two inputs and then summing the sequence with False and True values being interpreted as zero and one.
```def hamming_distance(s1, s2) -> int:
"""Return the Hamming distance between equal-length sequences."""
if len(s1) != len(s2):
raise ValueError("Undefined for sequences of unequal length.")
return sum(el1 != el2 for el1, el2 in zip(s1, s2))
```
where the zip() function merges two equal-length collections in pairs.
The following C function will compute the Hamming distance of two integers (considered as binary values, that is, as sequences of bits). The running time of this procedure is proportional to the Hamming distance rather than to the number of bits in the inputs. It computes the bitwise exclusive or of the two inputs, and then finds the Hamming weight of the result (the number of nonzero bits) using an algorithm of Wegner (1960) that repeatedly finds and clears the lowest-order nonzero bit. Some compilers support the __builtin_popcount function which can calculate this using specialized processor hardware where available.
```int hamming_distance(unsigned x, unsigned y)
{
int dist = 0;
// Count the number of bits set
for (unsigned val = x ^ y; val > 0; val >> 1)
{
// If A bit is set, so increment the count
if (val & 1)
dist++;
// Clear (delete) val's lowest-order bit
}
// Return the number of differing bits
return dist;
}
```
Or, a much faster hardware alternative (for compilers that support builtins) is to use popcount like so.
```int hamming_distance(unsigned x, unsigned y)
{
return __builtin_popcount(x ^ y);
}
//if your compiler supports 64-bit integers
int hamming_distance(unsigned long long x, unsigned long long y)
{
return __builtin_popcountll(x ^ y);
}
```
## References
1. Robinson, Derek J. S. (2003). An Introduction to Abstract Algebra. Walter de Gruyter. pp. 255–257. ISBN 978-3-11-019816-4.
2. Warren, Jr., Henry S. (2013) [2002]. Hacker's Delight (2 ed.). Addison Wesley - Pearson Education, Inc. pp. 81–96. ISBN 978-0-321-84268-8. 0-321-84268-5.
3. Cohen, G.; Honkala, I.; Litsyn, S.; Lobstein, A. (1997), Covering Codes, North-Holland Mathematical Library, 54, Elsevier, pp. 16–17, ISBN 9780080530079
4. Hamming, R. W. (April 1950). "Error detecting and error correcting codes" (PDF). The Bell System Technical Journal. 29 (2): 147–160. doi:10.1002/j.1538-7305.1950.tb00463.x. ISSN 0005-8580.
5. Ayala, Jose (2012). Integrated Circuit and System Design. Springer. p. 62. ISBN 978-3-642-36156-2.
6. Roth, Ron (2006). Introduction to Coding Theory. Cambridge University Press. p. 298. ISBN 978-0-521-84504-5.
7. Pilcher, Christopher D.; Wong, Joseph K.; Pillai, Satish K. (2008-03-18). "Inferring HIV Transmission Dynamics from Phylogenetic Sequence Relationships". PLOS Medicine. 5 (3): e69. doi:10.1371/journal.pmed.0050069. ISSN 1549-1676. PMC 2267810. PMID 18351799.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.
| 2020-10-24T04:05:33 |
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|
https://pos.sissa.it/377/051/
|
$CP$ violation and mixing in charm decays at LHCb
M. Schubiger
Full text: Not available
Abstract
The size of $CP$ violation allowed for by the Standard Model is orders of magnitude too small to explain our matter-dominated universe. Processes from physics beyond the Standard Model could enhance this violation and explain the observed asymmetry between matter and antimatter.
The charm sector is a relevant probe to search for New Physics processes and is complementary to other searches in the kaon and $B$ systems. $CP$ violation has recently been observed for the first time in charm decays by the LHCb collaboration. However, more work needs to be performed in order to understand the full picture.
These proceedings cover six recent analyses from LHCb that explore mixing and $CP$ violation in charm decays and contribute to a better understanding of this sector.
Open Access
Copyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
| 2020-02-21T10:32:33 |
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|
https://phys.libretexts.org/Bookshelves/University_Physics/Book%3A_University_Physics_(OpenStax)/Book%3A_University_Physics_I_-_Mechanics%2C_Sound%2C_Oscillations%2C_and_Waves_(OpenStax)/03%3A_Motion_Along_a_Straight_Line/3.05%3A_Motion_with_Constant_Acceleration_(Part_1)
|
$$\require{cancel}$$
# 3.5: Motion with Constant Acceleration (Part 1)
Learning Objectives
• Identify which equations of motion are to be used to solve for unknowns.
• Use appropriate equations of motion to solve a two-body pursuit problem.
You might guess that the greater the acceleration of, say, a car moving away from a stop sign, the greater the car’s displacement in a given time. But, we have not developed a specific equation that relates acceleration and displacement. In this section, we look at some convenient equations for kinematic relationships, starting from the definitions of displacement, velocity, and acceleration. We first investigate a single object in motion, called single-body motion. Then we investigate the motion of two objects, called two-body pursuit problems.
## Notation
First, let us make some simplifications in notation. Taking the initial time to be zero, as if time is measured with a stopwatch, is a great simplification. Since elapsed time is $$\Delta$$t = tf − t0, taking t0 = 0 means that $$\Delta$$t = tf, the final time on the stopwatch. When initial time is taken to be zero, we use the subscript 0 to denote initial values of position and velocity. That is, x0 is the initial position and v0 is the initial velocity. We put no subscripts on the final values. That is, t is the final time, x is the final position, and v is the final velocity. This gives a simpler expression for elapsed time, $$\Delta$$t = t. It also simplifies the expression for x displacement, which is now $$\Delta$$x = x − x0. Also, it simplifies the expression for change in velocity, which is now $$\Delta$$v = v − v0. To summarize, using the simplified notation, with the initial time taken to be zero,
$\Delta t = t$
$\Delta x = x - x_{0}$
$\Delta v = v - v_{0},$
where the subscript 0 denotes an initial value and the absence of a subscript denotes a final value in whatever motion is under consideration.
We now make the important assumption that acceleration is constant. This assumption allows us to avoid using calculus to find instantaneous acceleration. Since acceleration is constant, the average and instantaneous accelerations are equal—that is,
$\bar{a} = a = constant \ldotp$
Thus, we can use the symbol a for acceleration at all times. Assuming acceleration to be constant does not seriously limit the situations we can study nor does it degrade the accuracy of our treatment. For one thing, acceleration is constant in a great number of situations. Furthermore, in many other situations we can describe motion accurately by assuming a constant acceleration equal to the average acceleration for that motion. Lastly, for motion during which acceleration changes drastically, such as a car accelerating to top speed and then braking to a stop, motion can be considered in separate parts, each of which has its own constant acceleration.
## Displacement and Position from Velocity
To get our first two equations, we start with the definition of average velocity:
$\bar{v} = \frac{\Delta x}{\Delta t} \ldotp$
Substituting the simplified notation for $$\Delta$$x and $$\Delta$$t yields
$\bar{v} = \frac{x - x_{0}}{t} \ldotp$
Solving for x gives us
$x = x_{0} + \bar{v} t,\label{3.10}$
where the average velocity is
$\bar{v} = \frac{v_{0} + v}{2} \ldotp \label{3.11}$
The equation $$\bar{v} = \frac{v_{0} + v}{2}$$ reflects the fact that when acceleration is constant, v is just the simple average of the initial and final velocities. Figure $$\PageIndex{1}$$ illustrates this concept graphically. In part (a) of the figure, acceleration is constant, with velocity increasing at a constant rate. The average velocity during the 1-h interval from 40 km/h to 80 km/h is 60 km/h:
$\bar{v} = \frac{v_{0} + v}{2} = \frac{40\; km/h + 80\; km/h}{2} = 60\; km/h \ldotp$
In part (b), acceleration is not constant. During the 1-h interval, velocity is closer to 80 km/h than 40 km/h. Thus, the average velocity is greater than in part (a).
## Solving for Final Velocity from Acceleration and Time
We can derive another useful equation by manipulating the definition of acceleration:
$a = \frac{\Delta v}{\Delta t} \ldotp$
Substituting the simplified notation for $$\Delta$$v and $$\Delta$$t gives us
$a = \frac{v - v_{0}}{t}\; (constant\; a) \ldotp$
Solving for v yields
$v = v_{0} + at\; (constant\; a) \ldotp \label{3.12}$
Example 3.7: Calculating Final Velocity
An airplane lands with an initial velocity of 70.0 m/s and then decelerates at 1.50 m/s2 for 40.0 s. What is its final velocity?
Strategy
First, we identify the knowns: v0 = 70 m/s, a = −1.50 m/s2, t = 40 s.
Second, we identify the unknown; in this case, it is final velocity vf.
Last, we determine which equation to use. To do this we figure out which kinematic equation gives the unknown in terms of the knowns. We calculate the final velocity using Equation \ref{3.12}, v = v0 + at.
Solution
Substitute the known values and solve:
$v = v_{0} + at = 70.0\; m/s + (-1.50\; m/s^{2})(40.0\; s) = 10.0\; m/s \ldotp$
Figure $$\PageIndex{2}$$ is a sketch that shows the acceleration and velocity vectors.
Significance
The final velocity is much less than the initial velocity, as desired when slowing down, but is still positive (see figure). With jet engines, reverse thrust can be maintained long enough to stop the plane and start moving it backward, which is indicated by a negative final velocity, but is not the case here.
In addition to being useful in problem solving, the equation v = v0 + at gives us insight into the relationships among velocity, acceleration, and time. We can see, for example, that
• Final velocity depends on how large the acceleration is and how long it lasts
• If the acceleration is zero, then the final velocity equals the initial velocity (v = v0), as expected (in other words, velocity is constant)
• If a is negative, then the final velocity is less than the initial velocity
All these observations fit our intuition. Note that it is always useful to examine basic equations in light of our intuition and experience to check that they do indeed describe nature accurately.
## Solving for Final Position with Constant Acceleration
We can combine the previous equations to find a third equation that allows us to calculate the final position of an object experiencing constant acceleration. We start with
$v = v_{0} + at \ldotp$
Adding v0 to each side of this equation and dividing by 2 gives
$\frac{v_{0} + v}{2} = v_{0} + \frac{1}{2} at \ldotp$
Since $$\frac{v_{0} + v}{2} = \bar{v}$$ for constant acceleration, we have
$\bar{v} = v_{0} + \frac{1}{2} at \ldotp$
Now we substitute this expression for $$\bar{v}$$ into the equation for displacement, x = x0 + $$\bar{v}$$t, yielding
$x = x_{0} + v_{0}t + \frac{1}{2} at^{2}\; (constant\; a) \ldotp \label{3.13}$
Example 3.8: Calculating Displacement of an Accelerating Object
Dragsters can achieve an average acceleration of 26.0 m/s2. Suppose a dragster accelerates from rest at this rate for 5.56 s Figure $$\PageIndex{3}$$. How far does it travel in this time?
Strategy
First, let’s draw a sketch Figure $$\PageIndex{4}$$. We are asked to find displacement, which is x if we take x0 to be zero. (Think about x0 as the starting line of a race. It can be anywhere, but we call it zero and measure all other positions relative to it.) We can use the equation $$x = x_{0} + v_{0}t + \frac{1}{2} at^{2}$$ when we identify v0, a, and t from the statement of the problem.
Solution
First, we need to identify the knowns. Starting from rest means that v0 = 0 , a is given as 26.0 m/s2 and t is given as 5.56 s.
Second, we substitute the known values into the equation to solve for the unknown:
$x = x_{0} + v_{0}t + \frac{1}{2} at^{2} \ldotp$
Since the initial position and velocity are both zero, this equation simplifies to
$x = \frac{1}{2} at^{2} \ldotp$
Substituting the identified values of a and t gives
$x = \frac{1}{2} (26.0\; m/s^{2})(5.56\; s)^{2} = 402\; m \ldotp$
Significance
If we convert 402 m to miles, we find that the distance covered is very close to one-quarter of a mile, the standard distance for drag racing. So, our answer is reasonable. This is an impressive displacement to cover in only 5.56 s, but top-notch dragsters can do a quarter mile in even less time than this. If the dragster were given an initial velocity, this would add another term to the distance equation. If the same acceleration and time are used in the equation, the distance covered would be much greater.
What else can we learn by examining the equation $$x = x_{0} + v_{0}t + \frac{1}{2} at^{2}$$? We can see the following relationships:
• Displacement depends on the square of the elapsed time when acceleration is not zero. In Example 3.8, the dragster covers only one-fourth of the total distance in the first half of the elapsed time.
• If acceleration is zero, then initial velocity equals average velocity (v0 = $$\bar{v}$$) , and $$x = x_{0} + v_{0}t + \frac{1}{2} at^{2}$$ becomes x = x0 + v0t.
## Solving for Final Velocity from Distance and Acceleration
A fourth useful equation can be obtained from another algebraic manipulation of previous equations. If we solve v = v0 + at for t, we get
$t = \frac{v - v_{0}}{a} \ldotp$
Substituting this and $$\bar{v} = \frac{v_{0} + v}{2}$$ into $$x = x_{0} + \bar{v} t$$, we get
$v^{2} = v_{0}^{2} + 2a(x - x_{0})\; (constant\; a) \ldotp \label{3.14}$
Example 3.9: Calculating Final Velocity
Calculate the final velocity of the dragster in Example 3.8 without using information about time.
Strategy
The equation $$v^{2} = v_{0}^{2} + 2a(x - x_{0})$$ is ideally suited to this task because it relates velocities, acceleration, and displacement, and no time information is required.
Solution
First, we identify the known values. We know that v0 = 0, since the dragster starts from rest. We also know that x − x0 = 402 m (this was the answer in Example 3.8). The average acceleration was given by a = 26.0 m/s2. Second, we substitute the knowns into the equation $$v^{2} = v_{0}^{2} + 2a(x - x_{0})$$ and solve for v:
$v^{2} = 0 + 2(26.0\; m/s^{2})(402\; m) \ldotp$
Thus,
$v^{2} = 2.09 \times 10^{4}\; m/s^{2}$
$v = \sqrt{2.09 \times 10^{4}\; m^{2}/s^{2}} = 145\; m/s \ldotp$
Significance
A velocity of 145 m/s is about 522 km/h, or about 324 mi/h, but even this breakneck speed is short of the record for the quarter mile. Also, note that a square root has two values; we took the positive value to indicate a velocity in the same direction as the acceleration.
An examination of the equation $$v^{2} = v_{0}^{2} + 2a(x - x_{0})$$ can produce additional insights into the general relationships among physical quantities:
• The final velocity depends on how large the acceleration is and the distance over which it acts.
• For a fixed acceleration, a car that is going twice as fast doesn’t simply stop in twice the distance. It takes much farther to stop. (This is why we have reduced speed zones near schools.)
## Contributors and Attributions
• Samuel J. Ling (Truman State University), Jeff Sanny (Loyola Marymount University), and Bill Moebs with many contributing authors. This work is licensed by OpenStax University Physics under a Creative Commons Attribution License (by 4.0).
| 2021-03-06T14:18:40 |
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|
http://mathonline.wikidot.com/euler-s-method-examples-1
|
Euler's Method for Approximating Solutions to Diff. Eqs. Examples 1
# Euler's Method for Approximating Solutions to Differential Equations Examples 1
Recall from the Euler's Method for Approximating Solutions to Differential Equations page that if we have a first order differential equation $\frac{dy}{dt} = f(t, y)$ with the initial condition $y(t_0) = y_0$. If it is difficult to solve this first order differential equation, then sometimes we can use Euler's Method to find approximations $y_n$ of $\phi(t_n)$ with equations of lines that pass through the points $(t_n, y_n)$ with slopes $f(t_n, y_n)$ given by:
(1)
\begin{align} \quad y = y_n + f(t_n, y_n)(t - t_n) \end{align}
And the values of $y_{n+1}$ can be computed with the formula:
(2)
\begin{align} \quad y_{n+1} = y_n + f(t_n, y_n) (t_{n+1} - t_n) \end{align}
Furthermore, if the difference between consecutive values $v_j$ and $v_{j+1}$ is $h$ (the step size from one $v_j$ to the next is $h$) then the approximations $y_{n+1}$ of $\phi(t_{n+1})$ can be obtained by the formula:
(3)
\begin{align} \quad y_{n+1} = y_n + f(t_n, y_n) h \end{align}
We will now look at some more examples of using Euler's Method to approximate the solutions to differential equations.
## Example 1
Consider the first order differential equation $\frac{dy}{dt} = t^2 + y^2$ with the initial condition $y(0)=1$. Approximate the values of the unique solution $y = \phi (t)$ for this initial value problem using Euler's Method at the values $t=0.1,0.2,0.3,0.4, 0.5$ with the step size $h=0.1$.
Let $f(t, y) = \frac{dy}{dt} = t^2 + y^2$.
The tangent line that passes through the point $(0, 1)$ (given by the initial condition $y(0) = 1$) has the slope $f(0, 1) = 1^2 = 1$. Therefore the equation of this tangent line is:
(4)
\begin{align} \quad y = 1 + 1(t - 0) \end{align}
We will now use this line in order to approximate the value of $\phi(0.1)$. Plugging in $0.1$ to the tangent line above and we get that:
(5)
\begin{align} \quad y_1 = 1 + 1(0.1) \\ \quad y_1 = 1.1 \end{align}
We thus obtain the point $(0.1,1.1)$ as an approximation of $\phi(0.1)$. The slope of the tangent line that passes through this point is $f(0.1,1.1)=(0.1)^2 + (1.1)^2 = 1.22$. Therefore the equation of this tangent line is:
(6)
\begin{align} \quad y = 1.1 + 1.22(t - 0.1) \end{align}
We will now use this line in order to approximate the value of $\phi(0.2)$. Plugging in $0.2$ to the tangent line above and we get that:
(7)
\begin{align} \quad y_2 = 1.1 + 1.22(0.2 - 0.1) \\ \quad y_2 = 1.222 \end{align}
We thus obtain the point $(0.2, 1.222)$ as an approximation of $\phi(0.2)$. The slope of the tangent line that passes through this point is $f(0.2, 1.222) = 1.533284$. Therefore the equation of this tangent line is:
(8)
\begin{align} \quad y = 1.222 + 1.533284(t - 0.2) \end{align}
We will now use this line in order to approximate the value of $\phi(0.3)$. Plugging in $0.3$ to the tangent line above and we get that:
(9)
\begin{align} \quad y_3 = 1.222 + 1.533284(0.3 - 0.2) \\ \quad y_3 = 1.3753284 \end{align}
We thus obtain the point $(0.3, 1.3753284)$ as an approximation of $\phi(0.3)$. The slope of the tangent line that passes through this point is $f(0.3, 1.3753284) = 1.9815282$. Therefore the equation of this tangent line is:
(10)
\begin{align} \quad y = 1.3753284 + 1.9815282(t - 0.3) \end{align}
We will now use this line in order to approximate the value of $\phi(0.4)$. Plugging in $0.4$ to the tangent line above and we get that:
(11)
\begin{align} \quad y_4 = 1.3753284 + 1.9815282(0.4 - 0.3) \\ \quad y_4 = 1.5734812 \end{align}
We thus obtain the point $(0.4, 1.5734812)$ as an approximation of $\phi(0.4)$. The slope of the tangent line that passes through this point is $f(0.4, 1.5734812) = 2.6358431$. Therefore the equation of this tangent line is:
(12)
\begin{align} \quad y = 1.5734812 + 2.6358431(t - 0.4) \end{align}
We will now use this line in order to approximate the value of $\phi(0.5)$. Plugging in $0.5$ to the tangent line above and we get that:
(13)
\begin{align} \quad y_5 = 1.5734812 + 2.6358431(0.5 - 0.4) \\ \quad y_5 = 1.8370655 \end{align}
We thus obtain the point $(0.5, 1.8370655)$ as an approximation of $\phi(0.5)$.
The graph above shows the direction field of the differential equation $\frac{dy}{dt} = t^2 + y^2$ alongside the piecewise linear approximation curve (in red) creating by joining the line segments from the points $(t_0, y_0)$, $(t_1, y_1)$, …, $(t_5, y_5)$ obtained from Euler's Method which approximates the actual solution $y = \phi(t)$ to our initial value problem.
Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License
| 2018-10-22T14:19:49 |
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|
http://gams.cam.nist.gov/16.10
|
# §16.10 Expansions in Series of $\mathop{{{}_{p}F_{q}}\/}\nolimits$ Functions
The following expansion, with appropriate conditions and together with similar results, is given in Fields and Wimp (1961):
16.10.1 $\mathop{{{}_{p+r}F_{q+s}}\/}\nolimits\!\left({a_{1},\dots,a_{p},c_{1},\dots,c_% {r}\atop b_{1},\dots,b_{q},d_{1},\dots,d_{s}};z\zeta\right)=\sum_{k=0}^{\infty% }\frac{{\left(\mathbf{a}\right)_{k}}{\left(\alpha\right)_{k}}{\left(\beta% \right)_{k}}(-z)^{k}}{{\left(\mathbf{b}\right)_{k}}{\left(\gamma+k\right)_{k}}% k!}\mathop{{{}_{p+2}F_{q+1}}\/}\nolimits\!\left({\alpha+k,\beta+k,a_{1}+k,% \dots,a_{p}+k\atop\gamma+2k+1,b_{1}+k,\dots,b_{q}+k};z\right)\mathop{{{}_{r+2}% F_{s+2}}\/}\nolimits\!\left({-k,\gamma+k,c_{1},\dots,c_{r}\atop\alpha,\beta,d_% {1},\dots,d_{s}};\zeta\right).$
Here $\alpha$, $\beta$, and $\gamma$ are free real or complex parameters.
The next expansion is given in Nørlund (1955, equation (1.21)):
16.10.2 $\mathop{{{}_{p+1}F_{p}}\/}\nolimits\!\left({a_{1},\dots,a_{p+1}\atop b_{1},% \dots,b_{p}};z\zeta\right)=(1-z)^{-a_{1}}\sum_{k=0}^{\infty}\frac{{\left(a_{1}% \right)_{k}}}{k!}\mathop{{{}_{p+1}F_{p}}\/}\nolimits\!\left({-k,a_{2},\dots,a_% {p+1}\atop b_{1},\dots,b_{p}};\zeta\right)\left(\frac{z}{z-1}\right)^{k}.$
When $|\zeta-1|<1$ the series on the right-hand side converges in the half-plane $\Re{z}<\frac{1}{2}$.
Expansions of the form $\sum_{n=1}^{\infty}(\pm 1)^{n}\mathop{{{}_{p}F_{p+1}}\/}\nolimits\!\left(% \mathbf{a};\mathbf{b};-n^{2}z^{2}\right)$ are discussed in Miller (1997), and further series of generalized hypergeometric functions are given in Luke (1969b, Chapter 9), Luke (1975, §§5.10.2 and 5.11), and Prudnikov et al. (1990, §§5.3, 6.8–6.9).
| 2017-04-28T04:23:08 |
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|
http://demo.clab.cs.cmu.edu/sp2015-11731/hw4.html
|
Syllabus
# Homework 4
Due 11:59pm on Tuesday, April 21, 2015
In phrase based translation, the decoder makes use of a phrase table which contains translations of phrases in the source language into the target language, along with scores that give information about how probable or “good” the translation option is likely to be. For example, in an English–Czech MT system, the phrase table might tell us that there are two translations for the English word bank into Czech: banka and břeh (corresponding to the financial institution sense and river bank sense, respectively), with translation probabilities $p(\text{banka} \mid \text{bank}) = 0.8$ and $p(\text{břeh} \mid \text{bank}) = 0.2$. These probabilities are usually assumed to be the relative frequencies with which each source phrase was translated into each target phrase in the parallel corpus used to train the translation model.
Let us consider the problem of translating the following two English sentences into Czech:
i went to the bank to deposit my paycheck .
the log rolled down the bank and into the water .
Upon looking at these two input sentences, however, we might want to rethink the appropriateness of using context-independent relative frequencies to estimate the translation probabilities. In the former sentence, the correction translation of “bank” is seems likely to be banka (financial institution), just like our example phrase table predicts. In the latter, however, it’s more likely to be břeh (river bank) despite the translation table probabilities. This idea was first described in Carpuat and Wu (2007), but has only recently risen to prominence.
In this homework, your task is to use the context in the source sentence to rerank the translation options of the highlighted word.
This assignment will be graded by mean reciprocol rank (MRR), which captures the intuition that we want the “correct” translation (as determined by a reference sentence translation) to be highly ranked, even if it is not first in the reranked list. If the reference is the $n$th item in your reranked list, you will recieve a score of $\frac{1}{n}$ for that sentence. Your score is then averaged across all sentences in the test set, yielding a number between 0 (bad) and 1 (good).
## Getting started
Go to your clone of your course GitHub repository on the machine where you will be doing this assignment, and run the following command to obain the code and data you will need:
./tools/get-new-assignments
We have provided you with a trivial ranking algorithm that simply sorts the translation candidate list by $p(e \mid f)$. You will additionally be given several hundred thousand parallel Czech–English sentences along with some training data extracted therefrom. For convenience (and to inspire you!), we also provide dependency parses and POS tags for each input sentence in training, dev, and test sets.
### Provided data
We are providing you with training, development, and blind test datasets consisting of tuples $(x,c,y^*)$ of an English source phrase ($x$), the English sentential context ($c$), and a Czech reference translation of the English source phrase ($y^*$). You will also be provided with an English–Czech phrase table ($\mathscr{Y}$) which is guaranteed to contain the English source phrase and the Czech target phrase for every tuple we provide (of course, in a real system, you would need to deal with OOV words at test time).
At test time, you will be given a new set of tuples $(x, c)$ and asked to predict, for each of these, the corresponding $y$ from among all the translation options for $x$ that you find in the provided phrase table (we denote the set of translation options as $\mathscr{Y}(x)$).
## Data Formats
Training, dev, and test sets are all given in the same file format. Each line will contain one training sentence split into three parts using a triple pipe (“|||”) as the delimiter. The first part is the left context, the middle part is the phrase of interest, whose Czech translation we wish to predict, and the third is the right context. For example:
there are ten countries ||| along ||| this river .
Here “along” is the word we wish to translate into Czech. The reference translations are given in a corresponding file. For this example, the correct translation is podél.
## Baseline
The baseline you must implement (or beat) is a linear model that assigns a score to each phrase translation in the phrase table for a source language phrase in the context of a full sentence. That is, the baseline model assigns a score to a translation option in a source language context as $\textit{score}(x,c,y) = \mathbf{f}(x,c,y) \cdot \mathbf{w}$. For the baseline model, you are required to do two things: (i) engineer the feature functions $\mathbf{f}(x,c,y)$ (we discuss the required features below) and (ii) learn the weight vector $\mathbf{w}$ from a corpus of a training examples which pair the sources phrases ($x$) and contexts ($c$) with a correct translation ($y^*$).
If the training data we provided had “reference scores”, we could use linear regression to solve this problem. However, all we know is what translation was used in various different contexts (and of course, what other translations the model could have used—the phrase table). Therefore, to estimate the parameters of the scoring function, we will optimize the following pairwise ranking loss:
\begin{align*} \mathscr{L}(x, c, y^*) &= \sum_{y^- \in \mathscr{Y}(x) \setminus y^*} \max(0, \gamma - \textit{score}(x, c, y^*) + \textit{score}(x, c, y^-)) \\ &= \sum_{y^- \in \mathscr{Y}(x) \setminus y^*} \max(0, \gamma - \mathbf{f}(x, c, y^*) \cdot \mathbf{w} + \mathbf{f}(x, c, y^-) \cdot \mathbf{w}) \\ &= \sum_{y^- \in \mathscr{Y}(x) \setminus y^*} \max(0, \gamma - (\mathbf{f}(x, c, y^*) - \mathbf{f}(x, c, y^-)) \cdot \mathbf{w}) \\ \end{align*}
where $\mathbf{f}(x, c, y^*)$ is a function that takes a source phrase, context, and translation hypothesis and returns a vector of real-valued features and $w$ is a weight vector to be learned from training data. Here $\mathscr{L}(x, c, y^*)$ is per-instance loss, which should be summed over all training instances to calculate the total corpus loss.
Intuitively, what this objective says is that the score of the right translation ($y^*$) of $x$ in context $c$ needs to be higher than the score of all the other translations (the $y^-$) of $x$, by a margin of at least $\gamma$ (you can pick any number greater than 0 for $\gamma$; however note that if you set it to 0, there would be a degenerate solution which set $\mathbf{w}=0$ which would not be a very useful model). Thus, if ranks the wrong translation in context higher than the right translation, or if it picks the right answer, but its score is too close to that of the wrong answer, you will suffer a penalty.
Your learner should optimize this objective function using stochastic subgradient descent. That is, you should iteratively perform the update
$$\mathbf{w}_{(i+1)} = \mathbf{w}_{(i)} - \alpha \cdot \frac{\partial \mathscr{L}(x, c, y^*)}{\partial \mathbf{w}}$$
where $\alpha$ is some learning rate (the optimal value of the learning rate will depend on the features you use, but usually a value of 0.1 or 0.01 work well).
Despite all the notation, the stochastic subgradient descent algorithm for this model is very simple: you will loop over all $(x,c,y^*)$ tuples in the training data, and for each of these you will loop over all of the possible wrong answers (the $\mathscr{Y}(x) \setminus y^*$), you will then compute the following quantity:
\begin{align*} \mathscr{L}(x,c,y^*) = \max(0, \gamma - (\mathbf{f}(x, c, y^*) - \mathbf{f}(x, c, y^-)) \cdot \mathbf{w}) \end{align*}
If you get 0, your model is doing the right thing on this example. If you compute any non-zero score, you need to update the weights by following the direction of steepest descent, which is given by the derivative of $\gamma - (\mathbf{f}(x, c, y^*) - \mathbf{f}(x, c, y^-)) \cdot \mathbf{w}$ with respect to $\mathbf{w}$. Fortunately, this expression is very simple to differentiate: it is just a constant value plus a dot product, and the derivative of $c + \mathbf{a}\cdot\mathbf{b}$ with respect to $\mathbf{b}$ is just $\mathbf{a}$, so the derivative you need to compute is simply \begin{align*} \frac{\partial \mathscr{L}(x, c, y^*)}{\partial \mathbf{w}} = \mathbf{f}(x, c, y^-) - \mathbf{f}(x, c, y^*) \end{align*}
The baseline set of features you are to implement is a set of sparse features following two feature templates, along with the four features provided for each phrase in the phrase table:
• The four default phrase table features are the logs of the following four quantities: $p(e|f)$, $p(f|e)$, $p_{lex}(e|f)$, $p_{lex}(f|e)$.
• A binary feature that conjoins (i) the source word, (ii) the hypothesis translation, and (iii) the previous word in the target sentence. Written as a string, a feature might be src:bank_tgt:banka_prev:the, and it would have a value of 1.
• A binary feature that conjoins (i) the source word, (ii) the hypothesis translation, and (iii) the next word in the source sentence. An example feature string might look like src:bank_tgt:banka_next:the, and it would have a value of 1.
Note that this feature set is very sparse, yielding thousands of individual features. If you use Python, we recommend that you make use of scipy.sparse.csr_matrix to represent your feature vectors. There are equivalent sparse vector data types in almost every programming language.
To earn 7 points on this assignment, you must implement a the described learning algorithm using the above features so that it is capable of predicting which Czech translation of a highlighted source phrase is most likely given its context.
## Default model
To help get you started, we are providing a default model that four important features, $\log p(e|f)$, $\log p(f|e)$, $\log p_{lex}(e|f)$, and $\log p_{lex}(f|e)$. Furthermore, it uses the simple weight vector $(1\;0\;0\;0)$. Therefore it always simply sorts the candidates by $p(e \mid f)$. Thus, the default model is not sensitive to context.
## The Challenge
As discussed above, our baseline reranker simply sorts the candidates by $p(e|f)$. In our simple “bank” example, it would always then suggest banka over břeh.
Here are some ideas:
• Add $\ell_1$ or $\ell_2$ regularization to prevent the learner from assigning too much importance to rare features.
• Use convolutional neural networks to automatically learn to discriminate translations from context (paper)
• Leverage dependency and POS information to predict case (paper)
• Use lexical context and syntactic information (paper)
• Learn bilingual word vectors from parallel data (paper)
## Ground Rules
• You may work in independently or in groups of any size, under these conditions:
• You must notify us by posting a public note to piazza including the e-mails of everyone who will be working in the group (max=3).
• Everyone in the group will receive the same grade on the assignment.
• Once you have formed a group, you may not disband until the next homework.
• You must turn in the following by submitting to the public GitHub repository
• hw4/output.txt
• hw4/README.md - a brief description of the algorithms you tried.
• hw4/... - your source code and revision history. We want to see evidence of regular progress over the course of the project. You don’t have to git push to the public repository unless you want to, but you should be committing changes with git add and git commit. We expect to see evidence that you are trying things out and learning from what you see.
You do not need any other data than what is provided. You should feel free to use additional codebases and libraries. Nothing is off limits here – the sky is the limit! You may use other sources of data if you wish, provided that you notify the class via Piazza.
Unless otherwise indicated, this content has been adapted from this course by Chris Dyer. Both the original and new content are licensed under a Creative Commons Attribution 3.0 Unported License.
| 2017-09-21T14:01:47 |
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|
https://clinicalinfo.hiv.gov/en/glossary/therapeutic-index-ti
|
## Therapeutic Index (TI)
Audio
A ratio that compares the blood concentration at which a drug becomes toxic and the concentration at which the drug is effective. The larger the therapeutic index (TI), the safer the drug is. If the TI is small (the difference between the two concentrations is very small), the drug must be dosed carefully and the person receiving the drug should be monitored closely for any signs of drug toxicity.
Image(s): (Click to enlarge)
| 2022-06-26T14:48:42 |
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https://par.nsf.gov/biblio/10289594
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Sparse and smooth signal estimation: Convexification of L0 formulations
Signal estimation problems with smoothness and sparsity priors can be naturally modeled as quadratic optimization with L0-“norm” constraints. Since such problems are non-convex and hard-to-solve, the standard approach is, instead, to tackle their convex surrogates based on L1-norm relaxations. In this paper, we propose new iterative (convex) conic quadratic relaxations that exploit not only the L0-“norm” terms, but also the fitness and smoothness functions. The iterative convexification approach substantially closes the gap between the L0-“norm” and its L1 surrogate. These stronger relaxations lead to significantly better estimators than L1-norm approaches and also allow one to utilize affine sparsity priors. In addition, the parameters of the model and the resulting estimators are easily interpretable. Experiments with a tailored Lagrangian decomposition method indicate that the proposed iterative convex relaxations yield solutions within 1% of the exact L0-approach, and can tackle instances with up to 100,000 variables under one minute.
Authors:
; ;
Editors:
Award ID(s):
Publication Date:
NSF-PAR ID:
10289594
Journal Name:
Journal of machine learning research
Volume:
22
Issue:
52
Page Range or eLocation-ID:
1-43
ISSN:
1532-4435
5. Abstract We study the low-rank phase retrieval problem, where our goal is to recover a $d_1\times d_2$ low-rank matrix from a series of phaseless linear measurements. This is a fourth-order inverse problem, as we are trying to recover factors of a matrix that have been observed, indirectly, through some quadratic measurements. We propose a solution to this problem using the recently introduced technique of anchored regression. This approach uses two different types of convex relaxations: we replace the quadratic equality constraints for the phaseless measurements by a search over a polytope and enforce the rank constraint through nuclear norm regularization. The result is a convex program in the space of $d_1 \times d_2$ matrices. We analyze two specific scenarios. In the first, the target matrix is rank-$1$, and the observations are structured to correspond to a phaseless blind deconvolution. In the second, the target matrix has general rank, and we observe the magnitudes of the inner products against a series of independent Gaussian random matrices. In each of these problems, we show that anchored regression returns an accurate estimate from a near-optimal number of measurements given that we have access to an anchor matrix of sufficient quality. We also showmore »
| 2023-02-02T07:46:04 |
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https://www.usgs.gov/center-news/usgs-and-stakeholder-engagement-gulf-mexico
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# USGS and Stakeholder Engagement in the Gulf of Mexico
Release Date:
The U.S. coast of the Gulf of Mexico stretches about 1,631 miles from southern Florida through Alabama, Mississippi, and Louisiana, ending at the U.S.-Mexico border in Texas. Along this coastline are numerous types of coastal wetlands that provide many societal benefits. Coastal wetlands comprise grassy salt marshes, mangrove forests, freshwater forested swamps, freshwater marshes, and tidal flats. In addition to supporting fish and wildlife habitat, these wetlands improve water quality by filtering out excess nutrients and contaminants, sequester carbon and release oxygen, stabilize the shoreline to control erosion, provide recreation and tourism opportunities, and protect coastal communities from storms. USGS Climate Research and Development Program (Climate R&D) researchers are studying these important ecosystems and communicating with local natural resource managers to better inform their management.
Coastal wetlands have immense economic value, with estimates averaging about $194,000 per hectare per year on a global scale (2007 US$ price level) (Mehvar et al., 2018). For example, almost all the fish and shellfish caught by the fishing industry depend on estuaries and wetlands at some point in their life cycle, and the money brought in annually by the fishing industry in the Gulf region reaches hundreds of millions of dollars. Loss of healthy coastal wetland habitats can have severe impacts not only on fish populations, but on the fishing industry and regional economy as well. Coastal wetlands also incur economic value from their recreational use (fishing, kayaking, hiking, etc.), provisioning of raw materials (food, fiber, wood), and protective nature (prevent erosion, filter pollution, hold excess rain to help control flooding).
A succulent and grass-dominated salt marsh ecosystem in San Bernard National Wildlife Refuge (Texas). The succulent plants in the foreground of this photo are indicative of dry and hypersaline conditions. However, the high water levels shown in the photo are abnormal and due to very heavy rainfalls from Tropical Storm Imelda (September 2019; one of the wettest tropical cyclones on record in the USA). The photo was taken about two weeks after Imelda’s passage. Two years ago, this marsh was also inundated by very heavy rains associated with Hurricane Harvey (2017).
(Credit: Michael J. Osland, USGS. Public domain.)
However, due to their position at the land-sea interface, coastal wetlands are highly dynamic, variable, and vulnerable to major change. Coastal wetlands face pressure directly from natural coastal hazards such as flooding and erosion but also are indirectly threatened from human population growth and economic development. Coastal areas make up 4% of the land area on earth but are home to about a third of the global population, and the population density along the coasts continues to grow each year spurring increased land conversion and development (Mehvar et al., 2018). Additionally, as the planet’s climate changes, the natural hazard events that coastal wetlands are susceptible to, including changes in precipitation and warming temperatures, are expected to increase in probability and severity.
The Gulf Coast is home to many parks, refuges, and other public lands. Managers at those locations have responsibility for managing their lands to preserve natural resources and the services they provide. USGS scientists are collaborating with managers at Apalachicola National Estuarine Research Reserve (ANERR), Florida Forest Service (FFS), Florida Fish and Wildlife Research Institute (FWRI), and Mission Aransas National Estuarine Research Reserve (Mission-Aransas NERR) (among others) with the aim of providing unbiased, robust science to guide and support their environmental management decisions.
National, state, and locally protected natural areas, forests, parks, and wildlife reserves are located along the Gulf Coast (shown in shades of green). The four red stars on the map indicate the location of the four specific stakeholders surveyed for this piece. (Data Sources: U.S. Fish and Wildlife Service, National Park Service, National Oceanic and Atmospheric Administration NERRS SWMP Boundaries , State of Florida, State of Texas, State of Louisiana)
(Credit: Madeline Martin, USGS. Public domain.)
These resource managers are tasked with monitoring species, providing public use and access to natural lands, managing habitat and restoration efforts, protecting and managing natural resources to ensure their availability for future generations, collecting and analyzing scientific data to inform climate change adaptation, promoting understanding of coastal ecosystems to diverse audiences, and promoting public appreciation and support for stewardship of coastal resources.
Current State of Knowledge
Wetland vulnerability assessments have been used to identify coastal areas that are most susceptible to environmental change or stress. Previous coastal wetland vulnerability assessments have generally focused solely on sea-level rise without considering the effects of other facets of climate change. Across the globe and in all ecosystems, macroclimatic drivers (e.g., temperature and rainfall regimes) greatly influence ecosystem structure and function. In some coastal wetlands, research suggests that changing macroclimatic conditions could result in the replacement of foundation plant species (species that have a strong role in structuring an ecosystem, such as mangrove trees, salt marsh graminoids, and succulents in coastal wetlands).
Foundation plant species are able to withstand and moderate the physically stressful tidal conditions, and they provide primary, tolerable habitat for a wealth of other species. They supply important ecosystem goods and services, such as water filtration, and wave energy absorption, and increase the resilience of the ecosystem under a range of environmental stressors. USGS scientists are working to improve our understanding of the impact of macroclimate drivers and ecosystem dynamics in coastal ecosystems by documenting how changes in temperature and rainfall regimes affect coastal wetland systems.
A mangrove forest in Everglades National Park (Florida, USA). Mangrove forests in this area are greatly influenced by hurricanes and rising sea levels. The arching roots in this photo are called “prop roots” and are growing from red mangrove trees (Rhizophora mangle). Another common mangrove species in this area (the black mangrove- Avicennia germinans) produces roots called “pneumatophores” that extend vertically, perpendicular to the soil surface. High belowground mangrove root production in combination with marine sediments transported into these ecosystems during hurricanes can help some mangrove wetlands build soil elevation and adjust to (i.e., keep pace with) moderate rises in sea level.
(Credit: Michael J. Osland, USGS. Public domain.)
USGS Research Benefitting Gulf Coast Stakeholders
We recently began surveying stakeholders for USGS Climate R&D research to evaluate their science needs and potential synergies between them and USGS research efforts in order to maximize the relevance of our efforts to stakeholders in various federal, state, and local agencies.
A common goal of the stakeholders is development of adaptation plans for wildlife and ecosystems that promote long-term protection and management of valuable coastal resources given an uncertain future. Creating these adaptation plans is an important step in preparing and protecting local communities for any effects of change on the natural resources that they depend upon. USGS research on the impacts of macroclimatic changes on coastal foundation species is producing maps and projections of vegetation response to changing temperature and rainfall regimes. These provide important evidence that support management planning by resource managers in coastal wetlands.
Of particular interest to Gulf Coast stakeholders is USGS monitoring and mapping of salt marsh and mangrove extent under various past and future conditions. Maps of potential mangrove range expansion into salt marshes under different climate change scenarios allow stakeholders to identify priority conservation areas and create targeted monitoring programs. Likewise, maps of marsh migration under different growth and development scenarios allow stakeholders to weigh costs and benefits of different management strategies. Correlation of current mangrove forest extent maps with state forest inventory characteristics provides a way for state forest managers to better track and predict the future of mangrove ecosystems. Developing mangrove damage assessments after hurricanes also helps managers track the natural resources, they are responsible for and to identify potential areas for restoration projects.
The network of collaborating scientists and land managers from the USGS and agencies throughout the Southeast and Gulf Coast leverages their collective expertise to examine how changing land management and environmental factors affect coastal ecosystems in a comprehensive way. Local stakeholders and resource managers noted that they are able to spend more time focusing on the “bigger pictures” and regional trends in land management because USGS scientists are supplying rigorous, hypothesis-driven research and science products. Further, they are using USGS research to create targeted restoration projects and environmental resource monitoring programs in their locality.
A coastal wetland near Cedar Key National Wildlife Refuge (Florida) that contains a mixture of salt marsh grasses and mangrove trees. This location is near the northern range limit of mangrove forests in Florida. Thus, freeze events in the past have prevented mangrove forests from outcompeting the salt marsh plants. In the absence of freeze events, mangrove forests would dominate this wetland. The last major freeze event in this area occurred in December 1989, and mangroves have been expanding since then. The forests in the background are dominated by the black mangrove (Avicennia germinans) — the most freeze-tolerant mangrove species in North America.
(Credit: Michael J. Osland, USGS. Public domain.)
These collaborations also are helping USGS researchers tailor their research to address pressing questions while achieving a core mission of the agency: to provide reliable scientific information to describe and understand the Earth. As a result, scientists and resource managers are more effectively communicating the urgency and importance of environmental change issues in the region to the public, state and local governments, nonprofits, and universities they serve.
We gratefully acknowledge the support of the resource managers and stakeholder institutions who helped in the creation of this piece. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
References Cited
Mehvar, S., Filatova, T., Dastgheib, A., De Ruyter van Steveninck, E., and Ranasinghe, R., 2018, Quantifying economic value of coastal ecosystem services: a review: Journal of Marine Science and Engineering, v. 6, no. 1, doi: 10.3390/ jmse6010005. https://www.mdpi.com/2077-1312/6/1/5
A mangrove forest and adjacent mudflat near Big Sable Creek in Everglades National Park (Florida, USA). In this area, mangrove forest mortality and peat collapse due to a powerful tropical cyclone in 1935 led to the conversion of mangrove forests to mudflats. This area was once covered by more extensive mangrove forests but is now a mosaic of mangrove forest and mudflats.
(Credit: Michael J. Osland, USGS. Public domain.)
| 2021-04-15T17:06:52 |
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https://zbmath.org/authors/shu.chi-wang
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## Shu, Chi-Wang
Compute Distance To:
Author ID: shu.chi-wang Published as: Shu, Chi-Wang; Shu, Chiwang; Shu, C.-W.; Shu, C.; Shu, Chi-wang more...less Further Spellings: 舒其望 Homepage: https://www.dam.brown.edu/people/shu/ External Links: MGP · Wikidata · Google Scholar · ResearchGate · dblp · GND · IdRef · theses.fr
Documents Indexed: 439 Publications since 1987, including 3 Books 24 Contributions as Editor Biographic References: 1 Publication Co-Authors: 262 Co-Authors with 430 Joint Publications 9,996 Co-Co-Authors
all top 5
### Co-Authors
28 single-authored 44 Zhang, Mengping 24 Cheng, Juan 22 Qiu, Jianxian 20 Xu, Yan 20 Zhang, Qiang 16 Cockburn, Bernardo 14 Gottlieb, David I. 13 Xing, Yulong 13 Zhang, Yongtao 13 Zhu, Jun 12 Zhang, Shuhai 11 Carrillo de la Plata, José Antonio 11 Cheng, Yingda 11 Martínez Gamba, Irene 11 Liu, Yong 11 Zhang, Xiangxiong 10 Wang, Wei 9 Wang, Haijin 9 Xia, Yinhua 9 Yang, Yang 8 Liu, Yingjie 7 Amat, Sergio P. 7 E, Weinan 7 Lu, Jianfang 7 Osher, Stanley Joel 6 Cheng, Shiu-Yuen 6 Gottlieb, Sigal 6 Jerome, Joseph W. 6 Li, Fengyan 6 Majorana, Armando 6 Sun, Zheng 6 Tadmor, Eitan 6 Tan, Sirui 6 Wong, Sze Chun 6 Zhong, Xinghui 5 Du, Jie 5 Hu, Changqing 5 Huang, Juntao 5 Jiang, Yan 5 Kang, Ming-Chang 5 Liu, Kefeng 5 Liu, Yunxian 5 Meng, Xiong 5 Qiu, Jingmei 5 Ryan, Jennifer K. 5 Xu, Zhiliang 5 Yang, Lo 5 Yau, Shing-Tung 5 Yee, Helen C. 4 Abgrall, Rémi 4 Chou, Ching-Shan 4 Fu, Guosheng 4 Hesthaven, Jan S. 4 Lei, Nuo 4 Li, Jichun 4 Ling, Dan 4 Sjogreen, Bjorn 4 Wang, Cheng 4 Wu, Kailiang 4 Xiong, Tao 4 Xu, Zhengfu 4 Zhang, Zhimin 3 Bokanowski, Olivier 3 Cai, Wei 3 Cao, Waixiang 3 Chen, Shanqin 3 Chen, Tianheng 3 Dong, Bo 3 Filbet, Francis 3 Guo, Yan 3 Guzmán, Johnny 3 Jiang, Shufen 3 Karniadakis, George Em 3 Li, Tingting 3 Li, Yue 3 Liu, Yuan 3 Noelle, Sebastian 3 Shi, Cengke 3 Tang, Shanjian 3 Tao, Qi 3 Vilar, François 3 Wu, Boying 3 Yan, Jue 3 Yáñez, Dionisio F. 3 Zhang, Hanxin 3 Zhang, Peng 3 Zheng, Feng 3 Zhou, Tie 2 Araki, Luciano Kiyoshi 2 Atkins, Harold L. 2 Balsara, Dinshaw S. 2 Carpenter, Mark H. 2 Cercignani, Carlo 2 Chen, Yanlai 2 Chen, Zheng 2 da Silva, Nicholas Dicati P. 2 Dumbser, Michael 2 Erlebacher, Gordon 2 Fan, Haitao 2 Fang, Jinwei ...and 163 more Co-Authors
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### Serials
113 Journal of Computational Physics 43 Journal of Scientific Computing 30 SIAM Journal on Numerical Analysis 24 SIAM Journal on Scientific Computing 22 Communications in Computational Physics 16 European Series in Applied and Industrial Mathematics (ESAIM): Mathematical Modelling and Numerical Analysis 14 Mathematics of Computation 12 Computer Methods in Applied Mechanics and Engineering 10 Journal of Computational and Applied Mathematics 9 Computers and Fluids 9 Applied Numerical Mathematics 8 Numerische Mathematik 8 Journal of Computational Mathematics 8 Communications on Applied Mathematics and Computation 7 International Journal of Numerical Analysis and Modeling 6 Science China. Mathematics 5 M$$^3$$AS. Mathematical Models & Methods in Applied Sciences 5 Methods and Applications of Analysis 4 Physica D 4 Physics of Fluids 3 IMA Journal of Numerical Analysis 3 SIAM Review 3 Multiscale Modeling & Simulation 2 Computers & Mathematics with Applications 2 Journal of Fluid Mechanics 2 Transport Theory and Statistical Physics 2 Applied Mathematics and Computation 2 International Journal for Numerical Methods in Engineering 2 Quarterly of Applied Mathematics 2 Acta Mathematicae Applicatae Sinica. English Series 2 Applied Mathematics Letters 2 Contemporary Mathematics 2 Handbook of Numerical Analysis 2 Kinetic and Related Models 2 Annals of Mathematical Sciences and Applications 1 AIAA Journal 1 International Journal for Numerical Methods in Fluids 1 Nonlinearity 1 Physics of Fluids, A 1 Mathematica Numerica Sinica 1 SIAM Journal on Scientific and Statistical Computing 1 RAIRO. Modélisation Mathématique et Analyse Numérique 1 Numerical Methods for Partial Differential Equations 1 Applied Mathematical Modelling 1 SIAM Journal on Applied Mathematics 1 SIAM Journal on Mathematical Analysis 1 Notices of the American Mathematical Society 1 Chinese Science Bulletin 1 Computational and Applied Mathematics 1 Advances in Computational Mathematics 1 Engineering Analysis with Boundary Elements 1 International Journal of Computational Fluid Dynamics 1 Proceedings of the Royal Society of London. Series A. Mathematical, Physical and Engineering Sciences 1 Philosophical Transactions of the Royal Society of London. Series A. Mathematical, Physical and Engineering Sciences 1 Journal of Mathematical Study 1 Discrete and Continuous Dynamical Systems. Series B 1 Acta Mathematica Scientia. Series B. (English Edition) 1 Lecture Notes in Mathematics 1 Lecture Notes in Computational Science and Engineering 1 Acta Mechanica Sinica 1 Inverse Problems and Imaging 1 Advances in Applied Mathematics and Mechanics 1 Scientia Sinica. Mathematica 1 S$$\vec{\text{e}}$$MA Journal 1 Boletín de la Sociedad Española de Matemática Aplicada. S$$\vec{\text{e}}$$MA 1 Stochastic and Partial Differential Equations. Analysis and Computations 1 Advanced Courses in Mathematics – CRM Barcelona
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### Fields
380 Numerical analysis (65-XX) 244 Partial differential equations (35-XX) 166 Fluid mechanics (76-XX) 28 Statistical mechanics, structure of matter (82-XX) 18 General and overarching topics; collections (00-XX) 10 Calculus of variations and optimal control; optimization (49-XX) 9 Harmonic analysis on Euclidean spaces (42-XX) 9 Mechanics of deformable solids (74-XX) 9 Biology and other natural sciences (92-XX) 8 History and biography (01-XX) 8 Probability theory and stochastic processes (60-XX) 8 Optics, electromagnetic theory (78-XX) 8 Operations research, mathematical programming (90-XX) 7 Classical thermodynamics, heat transfer (80-XX) 5 Special functions (33-XX) 5 Ordinary differential equations (34-XX) 5 Approximations and expansions (41-XX) 4 Group theory and generalizations (20-XX) 4 Differential geometry (53-XX) 4 Computer science (68-XX) 4 Astronomy and astrophysics (85-XX) 3 Dynamical systems and ergodic theory (37-XX) 3 Mechanics of particles and systems (70-XX) 2 Nonassociative rings and algebras (17-XX) 2 Topological groups, Lie groups (22-XX) 2 Integral equations (45-XX) 2 Geophysics (86-XX) 1 Combinatorics (05-XX) 1 Number theory (11-XX) 1 Associative rings and algebras (16-XX) 1 Real functions (26-XX) 1 Relativity and gravitational theory (83-XX) 1 Systems theory; control (93-XX) 1 Information and communication theory, circuits (94-XX)
### Citations contained in zbMATH Open
398 Publications have been cited 24,306 times in 7,647 Documents Cited by Year
Efficient implementation of weighted ENO schemes. Zbl 0877.65065
Jiang, Guang-Shan; Shu, Chi-Wang
1996
Efficient implementation of essentially nonoscillatory shock-capturing schemes. Zbl 0653.65072
Shu, Chi-Wang; Osher, Stanley
1988
The local discontinuous Galerkin method for time-dependent convection-diffusion systems. Zbl 0927.65118
Cockburn, Bernardo; Shu, Chi-Wang
1998
Efficient implementation of essentially nonoscillatory shock-capturing schemes. II. Zbl 0674.65061
Shu, Chi-Wang; Osher, Stanley
1989
TVB Runge-Kutta local projection discontinuous Galerkin finite element method for conservation laws. II: General framework. Zbl 0662.65083
Cockburn, Bernardo; Shu, Chi-Wang
1989
The Runge-Kutta discontinuous Galerkin method for conservation laws. I: Multidimensional systems. Zbl 0920.65059
Cockburn, Bernardo; Shu, Chi-Wang
1998
Strong stability-preserving high-order time discretization methods. Zbl 0967.65098
Gottlieb, Sigal; Shu, Chi-Wang; Tadmor, Eitan
2001
Runge–Kutta discontinuous Galerkin methods for convection-dominated problems. Zbl 1065.76135
Cockburn, Bernardo; Shu, Chi-Wang
2001
TVB Runge-Kutta local projection discontinuous Galerkin finite element method for conservation laws. III: One-dimensional systems. Zbl 0677.65093
Cockburn, Bernardo; Lin, San-Yih; Shu, Chi-Wang
1989
Total variation diminishing Runge-Kutta schemes. Zbl 0897.65058
Gottlieb, Sigal; Shu, Chi-Wang
1998
The Runge-Kutta local projection discontinuous Galerkin finite element method for conservation laws. IV: The multidimensional case. Zbl 0695.65066
Cockburn, Bernardo; Hou, Suchung; Shu, Chi-Wang
1990
Essentially non-oscillatory and weighted essentially non-oscillatory schemes for hyperbolic conservation laws. Zbl 0927.65111
Shu, Chi-Wang
1998
Monotonicity preserving weighted essentially non-oscillatory schemes with increasingly high order of accuracy. Zbl 0961.65078
Balsara, Dinshaw S.; Shu, Chi-Wang
2000
Total-variation-diminishing time discretizations. Zbl 0662.65081
Shu, Chiwang
1988
High order weighted essentially nonoscillatory schemes for convection dominated problems. Zbl 1160.65330
Shu, Chi-Wang
2009
Weighted essentially non-oscillatory schemes on triangular meshes. Zbl 0926.65090
Hu, Changqing; Shu, Chi-Wang
1999
The development of discontinuous Galerkin methods. Zbl 0989.76045
Cockburn, Bernardo; Karniadakis, George E.; Shu, Chi-Wang
2000
On positivity-preserving high order discontinuous Galerkin schemes for compressible Euler equations on rectangular meshes. Zbl 1282.76128
Zhang, Xiangxiong; Shu, Chi-Wang
2010
High-order essentially nonoscillatory schemes for Hamilton-Jacobi equations. Zbl 0736.65066
Osher, Stanley; Shu, Chi-Wang
1991
The Runge-Kutta local projection $$P^ 1$$-discontinuous-Galerkin finite element method for scalar conservation laws. Zbl 0732.65094
Cockburn, Bernardo; Shu, Chi-Wang
1991
On maximum-principle-satisfying high order schemes for scalar conservation laws. Zbl 1187.65096
Zhang, Xiangxiong; Shu, Chi-Wang
2010
On the Gibbs phenomenon and its resolution. Zbl 0885.42003
Gottlieb, David; Shu, Chi-Wang
1997
A local discontinuous Galerkin method for KdV type equations. Zbl 1021.65050
Yan, Jue; Shu, Chi-Wang
2002
A technique of treating negative weights in WENO schemes. Zbl 0992.65094
Shi, Jing; Hu, Changqing; Shu, Chi-Wang
2002
Runge-Kutta discontinuous Galerkin method using WENO limiters. Zbl 1077.65109
Qiu, Jianxian; Shu, Chi-Wang
2005
Hermite WENO schemes and their application as limiters for Runge-Kutta discontinuous Galerkin method: One-dimensional case. Zbl 1039.65068
Qiu, Jianxian; Shu, Chi-Wang
2004
Strong stability preserving Runge-Kutta and multistep time discretizations. Zbl 1241.65064
Gottlieb, Sigal; Ketcheson, David; Shu, Chi-Wang
2011
Maximum-principle-satisfying and positivity-preserving high-order schemes for conservation laws: survey and new developments. Zbl 1222.65107
Zhang, Xiangxiong; Shu, Chi-Wang
2011
High order finite difference WENO schemes with the exact conservation property for the shallow water equations. Zbl 1114.76340
Xing, Yulong; Shu, Chi-Wang
2005
TVB uniformly high-order schemes for conservation laws. Zbl 0628.65075
Shu, Chiwang
1987
Hermite WENO schemes and their application as limiters for Runge-Kutta discontinuous Galerkin method. II: Two dimensional case. Zbl 1134.65358
Qiu, Jianxian; Shu, Chi-Wang
2005
Locally divergence-free discontinuous Galerkin methods for the Maxwell equations. Zbl 1049.78019
Cockburn, Bernardo; Li, Fengyan; Shu, Chi-Wang
2004
High order strong stability preserving time discretizations. Zbl 1203.65135
Gottlieb, Sigal; Ketcheson, David I.; Shu, Chi-Wang
2009
Local discontinuous Galerkin methods for high-order time-dependent partial differential equations. Zbl 1364.65205
Xu, Yan; Shu, Chi-Wang
2010
Resolution of high order WENO schemes for complicated flow structures. Zbl 1047.76081
Shi, Jing; Zhang, Yong-Tao; Shu, Chi-Wang
2003
Local discontinuous Galerkin methods for nonlinear Schrödinger equations. Zbl 1072.65130
Xu, Yan; Shu, Chi-Wang
2005
High-order well-balanced finite volume WENO schemes for shallow water equation with moving water. Zbl 1120.76046
Noelle, Sebastian; Xing, Yulong; Shu, Chi-Wang
2007
High order well-balanced finite volume WENO schemes and discontinuous Galerkin methods for a class of hyperbolic systems with source terms. Zbl 1089.65091
Xing, Yulong; Shu, Chi-Wang
2006
On the construction, comparison, and local characteristic decomposition for high-order central WENO schemes. Zbl 1018.65106
Qiu, Jianxian; Shu, Chi-Wang
2002
High-order finite difference and finite volume WENO schemes and discontinuous Galerkin methods for CFD. Zbl 1034.76044
Shu, Chi-Wang
2003
Maximum-principle-satisfying and positivity-preserving high order discontinuous Galerkin schemes for conservation laws on triangular meshes. Zbl 1247.65131
Zhang, Xiangxiong; Xia, Yinhua; Shu, Chi-Wang
2012
Error estimates to smooth solutions of Runge-Kutta discontinuous Galerkin methods for scalar conservation laws. Zbl 1078.65080
Zhang, Qiang; Shu, Chi-Wang
2004
An efficient class of WENO schemes with adaptive order. Zbl 1422.65146
Balsara, Dinshaw S.; Garain, Sudip; Shu, Chi-Wang
2016
Runge-Kutta discontinuous Galerkin method using WENO limiters II: Unstructured meshes. Zbl 1157.65453
Zhu, Jun; Qiu, Jianxian; Shu, Chi-Wang; Dumbser, Michael
2008
Positivity-preserving high order discontinuous Galerkin schemes for compressible Euler equations with source terms. Zbl 1391.76375
Zhang, Xiangxiong; Shu, Chi-Wang
2011
A discontinuous Galerkin finite element method for Hamilton-Jacobi equations. Zbl 0946.65090
Hu, Changqing; Shu, Chi-Wang
1999
Local discontinuous Galerkin methods for partial differential equations with higher order derivatives. Zbl 1003.65115
Yan, Jue; Shu, Chi-Wang
2002
A comparison of troubled-cell indicators for Runge-Kutta discontinuous Galerkin methods using weighted essentially nonoscillatory limiters. Zbl 1092.65084
Qiu, Jianxian; Shu, Chi-Wang
2005
High-order WENO schemes for Hamilton-Jacobi equations on triangular meshes. Zbl 1034.65051
Zhang, Yong-Tao; Shu, Chi-Wang
2003
Positivity-preserving high order finite difference WENO schemes for compressible Euler equations. Zbl 1426.76493
Zhang, Xiangxiong; Shu, Chi-Wang
2012
Entropy stable high order discontinuous Galerkin methods with suitable quadrature rules for hyperbolic conservation laws. Zbl 1380.65253
Chen, Tianheng; Shu, Chi-Wang
2017
On a cell entropy inequality for discontinuous Galerkin methods. Zbl 0801.65098
Jiang, Guangshan; Shu, Chi-Wang
1994
A discontinuous Galerkin finite element method for time dependent partial differential equations with higher order derivatives. Zbl 1141.65075
Cheng, Yingda; Shu, Chi-Wang
2008
On positivity preserving finite volume schemes for Euler equations. Zbl 0857.76062
Perthame, Benoit; Shu, Chi-Wang
1996
Enhanced accuracy by post-processing for finite element methods for hyperbolic equations. Zbl 1015.65049
Cockburn, Bernardo; Luskin, Mitchell; Shu, Chi-Wang; Süli, Endre
2003
Superconvergence of discontinuous Galerkin and local discontinuous Galerkin schemes for linear hyperbolic and convection-diffusion equations in one space dimension. Zbl 1208.65137
Cheng, Yingda; Shu, Chi-Wang
2010
A high-order ENO conservative Lagrangian type scheme for the compressible Euler equations. Zbl 1126.76035
Cheng, Juan; Shu, Chi-Wang
2007
Third order WENO scheme on three dimensional tetrahedral meshes. Zbl 1364.65177
Zhang, Yong-Tao; Shu, Chi-Wang
2009
Runge-Kutta discontinuous Galerkin method using a new type of WENO limiters on unstructured meshes. Zbl 1349.65501
Zhu, Jun; Zhong, Xinghui; Shu, Chi-Wang; Qiu, Jianxian
2013
Local discontinuous Galerkin methods for the Cahn-Hilliard type equations. Zbl 1131.65088
Xia, Yinhua; Xu, Yan; Shu, Chi-Wang
2007
Central discontinuous Galerkin methods on overlapping cells with a nonoscillatory hierarchical reconstruction. Zbl 1157.65450
Liu, Yingjie; Shu, Chi-Wang; Tadmor, Eitan; Zhang, Mengping
2007
Error estimates of the semi-discrete local discontinuous Galerkin method for nonlinear convection-diffusion and KdV equations. Zbl 1173.65338
Xu, Yan; Shu, Chi-Wang
2007
Stability analysis and a priori error estimates of the third order explicit Runge-Kutta discontinuous Galerkin method for scalar conservation laws. Zbl 1217.65178
Zhang, Qiang; Shu, Chi-Wang
2010
On the Gibbs phenomenon. I: Recovering exponential accuracy from the Fourier partial sum of a nonperiodic analytic function. Zbl 0781.42022
Gottlieb, David; Shu, Chi-Wang; Solomonoff, Alex; Vandeven, Hervé
1992
Positivity-preserving method for high-order conservative schemes solving compressible Euler equations. Zbl 1311.76088
Hu, Xiangyu Y.; Adams, Nikolaus A.; Shu, Chi-Wang
2013
Anti-diffusive flux corrections for high order finite difference WENO schemes. Zbl 1087.76080
Xu, Zhengfu; Shu, Chi-Wang
2005
A local discontinuous Galerkin method for the Camassa-Holm equation. Zbl 1173.65063
Xu, Yan; Shu, Chi-Wang
2008
Local discontinuous Galerkin methods for nonlinear dispersive equations. Zbl 1055.65109
Levy, Doron; Shu, Chi-Wang; Yan, Jue
2004
Optimal error estimates of the semidiscrete local discontinuous Galerkin methods for high order wave equations. Zbl 1247.65121
Xu, Yan; Shu, Chi-Wang
2012
High order ENO and WENO schemes for computational fluid dynamics. Zbl 0937.76044
Shu, Chi-Wang
1999
A new approach of high order well-balanced finite volume WENO schemes and discontinuous Galerkin methods for a class of hyperbolic systems with source terms. Zbl 1115.65096
Xing, Yulong; Shu, Chi-Wang
2006
Locally divergence-free discontinuous Galerkin methods for MHD equations. Zbl 1123.76341
Li, Fengyan; Shu, Chi-Wang
2005
Small-scale structures in Boussinesq convection. Zbl 0822.76087
E, Weinan; Shu, Chi-Wang
1994
Positivity preserving semi-Lagrangian discontinuous Galerkin formulation: theoretical analysis and application to the Vlasov-Poisson system. Zbl 1273.65147
Qiu, Jing-Mei; Shu, Chi-Wang
2011
Analysis of optimal superconvergence of discontinuous Galerkin method for linear hyperbolic equations. Zbl 1276.65055
Yang, Yang; Shu, Chi-Wang
2012
Development of nonlinear weighted compact schemes with increasingly higher order accuracy. Zbl 1152.65094
Zhang, Shuhai; Jiang, Shufen; Shu, Chi-Wang
2008
Numerical experiments on the accuracy of ENO and modified ENO schemes. Zbl 0732.65085
Shu, Chi-Wang
1990
Inverse Lax-Wendroff procedure for numerical boundary conditions of conservation laws. Zbl 1198.65174
Tan, Sirui; Shu, Chi-Wang
2010
Stability and error estimates of local discontinuous Galerkin methods with implicit-explicit time-marching for advection-diffusion problems. Zbl 1327.65179
Wang, Haijin; Shu, Chi-Wang; Zhang, Qiang
2015
High order WENO and DG methods for time-dependent convection-dominated PDEs: A brief survey of several recent developments. Zbl 1349.65486
Shu, Chi-Wang
2016
The discontinuous Galerkin method with Lax–Wendroff type time discretizations. Zbl 1093.76038
Qiu, Jianxian; Dumbser, Michael; Shu, Chi-Wang
2005
Finite difference WENO schemes with Lax-Wendroff-type time discretizations. Zbl 1034.65073
Qiu, Jianxian; Shu, Chi-Wang
2003
Robust high order discontinuous Galerkin schemes for two-dimensional gaseous detonations. Zbl 1243.80011
Wang, Cheng; Zhang, Xiangxiong; Shu, Chi-Wang; Ning, Jianguo
2012
Local discontinuous Galerkin methods for the Kuramoto-Sivashinsky equations and the Ito-type coupled KdV equations. Zbl 1124.76035
Xu, Yan; Shu, Chi-Wang
2006
Analysis of a local discontinuous Galerkin method for linear time-dependent fourth-order problems. Zbl 1204.65123
Dong, Bo; Shu, Chi-Wang
2009
A high-order discontinuous Galerkin method for 2D incompressible flows. Zbl 0963.76069
Liu, Jian-Guo; Shu, Chi-Wang
2000
Maximum-principle-satisfying second order discontinuous Galerkin schemes for convection-diffusion equations on triangular meshes. Zbl 1284.65140
Zhang, Yifan; Zhang, Xiangxiong; Shu, Chi-Wang
2013
Discontinuous Galerkin methods. Theory, computation and applications. 1st international symposium on DGM, Newport, RI, USA, May 24–26, 1999. Zbl 0935.00043
2000
Nonlinearly stable compact schemes for shock calculations. Zbl 0805.65085
Cockburn, Bernardo; Shu, Chi-Wang
1994
Conservative high order semi-Lagrangian finite difference WENO methods for advection in incompressible flow. Zbl 1391.76489
Qiu, Jing-Mei; Shu, Chi-Wang
2011
Optimal error estimates for discontinuous Galerkin methods based on upwind-biased fluxes for linear hyperbolic equations. Zbl 1332.65148
Meng, Xiong; Shu, Chi-Wang; Wu, Boying
2016
A survey of high order schemes for the shallow water equations. Zbl 1324.76035
Xing, Yulong; Shu, Chi-Wang
2014
An analysis of three different formulations of the discontinuous Galerkin method for diffusion equations. Zbl 1050.65094
Zhang, Mengping; Shu, Chi-Wang
2003
A new type of multi-resolution WENO schemes with increasingly higher order of accuracy. Zbl 1416.65286
Zhu, Jun; Shu, Chi-Wang
2018
Local discontinuous Galerkin methods for two classes of two-dimensional nonlinear wave equations. Zbl 1078.35111
Xu, Yan; Shu, Chi-Wang
2005
A discontinuous Galerkin finite element method for directly solving the Hamilton-Jacobi equations. Zbl 1124.65090
Cheng, Yingda; Shu, Chi-Wang
2007
$$L^{2}$$ stability analysis of the central discontinuous Galerkin method and a comparison between the central and regular discontinuous Galerkin methods. Zbl 1152.65095
Liu, Yingjie; Shu, Chi-Wang; Tadmor, Eitan; Zhang, Mengping
2008
A numerical study for the performance of the Runge-Kutta discontinuous Galerkin method based on different numerical fluxes. Zbl 1083.65093
Qiu, Jianxian; Khoo, Boo Cheong; Shu, Chi-Wang
2006
High order conservative Lagrangian schemes with Lax-Wendroff type time discretization for the compressible Euler equations. Zbl 1287.76181
Liu, Wei; Cheng, Juan; Shu, Chi-Wang
2009
On the order of accuracy and numerical performance of two classes of finite volume WENO schemes. Zbl 1364.65176
Zhang, Rui; Zhang, Mengping; Shu, Chi-Wang
2011
Stability analysis of inverse Lax-Wendroff boundary treatment of high order compact difference schemes for parabolic equations. Zbl 1481.65145
Li, Tingting; Lu, Jianfang; Shu, Chi-Wang
2022
A high order positivity-preserving conservative WENO remapping method on 3D tetrahedral meshes. Zbl 07532592
Lei, Nuo; Cheng, Juan; Shu, Chi-Wang
2022
An essentially oscillation-free discontinuous Galerkin method for hyperbolic systems. Zbl 1484.65226
Liu, Yong; Lu, Jianfang; Shu, Chi-Wang
2022
A high order positivity-preserving conservative WENO remapping method on 2D quadrilateral meshes. Zbl 07337779
Lei, Nuo; Cheng, Juan; Shu, Chi-Wang
2021
Provably physical-constraint-preserving discontinuous Galerkin methods for multidimensional relativistic MHD equations. Zbl 1480.65271
Wu, Kailiang; Shu, Chi-Wang
2021
An inverse Lax-Wendroff procedure for hyperbolic conservation laws with changing wind direction on the boundary. Zbl 07510055
Lu, Jianfang; Shu, Chi-Wang; Tan, Sirui; Zhang, Mengping
2021
An oscillation-free discontinuous Galerkin method for scalar hyperbolic conservation laws. Zbl 1467.65095
Lu, Jianfang; Liu, Yong; Shu, Chi-Wang
2021
High-order Runge-Kutta discontinuous Galerkin methods with a new type of multi-resolution WENO limiters on tetrahedral meshes. Zbl 1474.65379
Zhu, Jun; Shu, Chi-Wang; Qiu, Jianxian
2021
Enforcing strong stability of explicit Runge-Kutta methods with superviscosity. Zbl 1499.65305
Sun, Zheng; Shu, Chi-Wang
2021
On a class of splines free of Gibbs phenomenon. Zbl 1480.65028
Amat, Sergio; Ruiz, Juan; Shu, Chi-Wang; Trillo, Juan Carlos
2021
A high order conservative finite difference scheme for compressible two-medium flows. Zbl 07515853
Zheng, Feng; Shu, Chi-Wang; Qiu, Jianxian
2021
Multi-resolution HWENO schemes for hyperbolic conservation laws. Zbl 07516463
Li, Jiayin; Shu, Chi-Wang; Qiu, Jianxian
2021
High-order Runge-Kutta discontinuous Galerkin methods with multi-resolution WENO limiters for solving steady-state problems. Zbl 1475.65140
Zhu, Jun; Shu, Chi-Wang; Qiu, Jianxian
2021
Dissipative and conservative local discontinuous Galerkin methods for the Fornberg-Whitham type equations. Zbl 1473.65225
Zhang, Qian; Xu, Yan; Shu, Chi-Wang
2021
Cell-average WENO with progressive order of accuracy close to discontinuities with applications to signal processing. Zbl 07423609
Amat, Sergio; Ruiz-Álvarez, Juan; Shu, Chi-Wang; Yáñez, Dionisio F.
2021
Sub-optimal convergence of discontinuous Galerkin methods with central fluxes for linear hyperbolic equations with even degree polynomial approximations. Zbl 1499.65507
Liu, Yong; Shu, Chi-Wang; Zhang, Mengping
2021
A discontinuous Galerkin method and its error estimate for nonlinear fourth-order wave equations. Zbl 1456.65124
Tao, Qi; Xu, Yan; Shu, Chi-Wang
2021
Weighted ghost fluid discontinuous Galerkin method for two-medium problems. Zbl 07510069
Liu, Yun-Long; Shu, Chi-Wang; Zhang, A-Man
2021
A local discontinuous Galerkin method for nonlinear parabolic SPDEs. Zbl 1480.65019
Li, Yunzhang; Shu, Chi-Wang; Tang, Shanjian
2021
A new type of third-order finite volume multi-resolution WENO schemes on tetrahedral meshes. Zbl 1453.65266
Zhu, Jun; Shu, Chi-Wang
2020
High-order Runge-Kutta discontinuous Galerkin methods with a new type of multi-resolution WENO limiters. Zbl 1453.65351
Zhu, Jun; Qiu, Jianxian; Shu, Chi-Wang
2020
Local discontinuous Galerkin methods with explicit-implicit-null time discretizations for solving nonlinear diffusion problems. Zbl 1434.65196
Wang, Haijin; Zhang, Qiang; Wang, Shiping; Shu, Chi-Wang
2020
High-order Runge-Kutta discontinuous Galerkin methods with a new type of multi-resolution WENO limiters on triangular meshes. Zbl 1436.65118
Zhu, Jun; Shu, Chi-Wang; Qiu, Jianxian
2020
Entropy symmetrization and high-order accurate entropy stable numerical schemes for relativistic MHD equations. Zbl 1450.65089
Wu, Kailiang; Shu, Chi-Wang
2020
A discontinuous Galerkin method for stochastic conservation laws. Zbl 07149719
Li, Yunzhang; Shu, Chi-Wang; Tang, Shanjian
2020
Superconvergence analysis of the Runge-Kutta discontinuous Galerkin methods for a linear hyperbolic equation. Zbl 1465.65105
Xu, Yuan; Meng, Xiong; Shu, Chi-Wang; Zhang, Qiang
2020
Optimal error estimates of the semidiscrete discontinuous Galerkin methods for two dimensional hyperbolic equations on Cartesian meshes using $$P^k$$ elements. Zbl 1439.65115
Liu, Yong; Shu, Chi-Wang; Zhang, Mengping
2020
Well-balanced finite-volume schemes for hydrodynamic equations with general free energy. Zbl 1434.82098
Carrillo, José A.; Kalliadasis, Serafim; Perez, Sergio P.; Shu, Chi-Wang
2020
An ultraweak-local discontinuous Galerkin method for PDEs with high order spatial derivatives. Zbl 1446.65118
Tao, Qi; Xu, Yan; Shu, Chi-Wang
2020
Error estimate of the fourth-order Runge-Kutta discontinuous Galerkin methods for linear hyperbolic equations. Zbl 1452.65256
Xu, Yuan; Shu, Chi-Wang; Zhang, Qiang
2020
On the conservation of finite difference WENO schemes in non-rectangular domains using the inverse Lax-Wendroff boundary treatments. Zbl 1440.65086
Ding, Shengrong; Shu, Chi-Wang; Zhang, Mengping
2020
On a new WENO algorithm of order $$2 r$$ with improved accuracy close to discontinuities. Zbl 07187420
Amat, Sergio; Ruiz, Juan; Shu, Chi-Wang
2020
A new WENO-$$2r$$ algorithm with progressive order of accuracy close to discontinuities. Zbl 1457.65038
Amat, Sergio P.; Ruiz, Juan; Shu, Chi-Wang; Yáñez, Dionisio F.
2020
Convergence to steady-state solutions of the new type of high-order multi-resolution WENO schemes: a numerical study. Zbl 1476.65200
Zhu, Jun; Shu, Chi-Wang
2020
Analysis of optimal superconvergence of an ultraweak-local discontinuous Galerkin method for a time dependent fourth-order equation. Zbl 1476.65242
Liu, Yong; Tao, Qi; Shu, Chi-Wang
2020
An ultra-weak discontinuous Galerkin method with implicit-explicit time-marching for generalized stochastic KdV equations. Zbl 1434.65015
Li, Yunzhang; Shu, Chi-Wang; Tang, Shanjian
2020
On moving mesh WENO schemes with characteristic boundary conditions for Hamilton-Jacobi equations. Zbl 07211850
Li, Yue; Cheng, Juan; Xia, Yinhua; Shu, Chi-Wang
2020
Existence and computation of solutions of a model of traffic involving hysteresis. Zbl 1454.35235
Fan, Haitao; Shu, Chi-Wang
2020
On new strategies to control the accuracy of WENO algorithm close to discontinuities. II: Cell averages and multiresolution. Zbl 1463.65213
Amat, Sergio; Ruiz, Juan; Shu, Chiwang
2020
High order conservative Lagrangian schemes for one-dimensional radiation hydrodynamics equations in the equilibrium-diffusion limit. Zbl 07508352
Cheng, Juan; Shu, Chi-Wang; Song, Peng
2020
Positivity-preserving time discretizations for production-destruction equations with applications to non-equilibrium flows. Zbl 1420.35190
Huang, Juntao; Shu, Chi-Wang
2019
A new type of multi-resolution WENO schemes with increasingly higher order of accuracy on triangular meshes. Zbl 1452.76143
Zhu, Jun; Shu, Chi-Wang
2019
Provably positive high-order schemes for ideal magnetohydrodynamics: analysis on general meshes. Zbl 1419.76446
Wu, Kailiang; Shu, Chi-Wang
2019
Strong stability of explicit Runge-Kutta time discretizations. Zbl 1422.65224
Sun, Zheng; Shu, Chi-Wang
2019
The $$\mathrm{L}^2$$-norm stability analysis of Runge-Kutta discontinuous Galerkin methods for linear hyperbolic equations. Zbl 1422.65272
Xu, Yuan; Zhang, Qiang; Shu, Chi-Wang; Wang, Haijin
2019
A third-order unconditionally positivity-preserving scheme for production-destruction equations with applications to non-equilibrium flows. Zbl 1444.35125
Huang, Juntao; Zhao, Weifeng; Shu, Chi-Wang
2019
Stability analysis and error estimates of arbitrary Lagrangian-Eulerian discontinuous Galerkin method coupled with Runge-Kutta time-marching for linear conservation laws. Zbl 1418.65141
Zhou, Lingling; Xia, Yinhua; Shu, Chi-Wang
2019
An entropy stable high-order discontinuous Galerkin method for cross-diffusion gradient flow systems. Zbl 1420.65095
Sun, Zheng; Carrillo, José A.; Shu, Chi-Wang
2019
Implicit-explicit local discontinuous Galerkin methods with generalized alternating numerical fluxes for convection-diffusion problems. Zbl 1434.65195
Wang, Haijin; Zhang, Qiang; Shu, Chi-Wang
2019
An energy-conserving ultra-weak discontinuous Galerkin method for the generalized Korteweg-de Vries equation. Zbl 1407.65187
Fu, Guosheng; Shu, Chi-Wang
2019
Local discontinuous Galerkin methods with implicit-explicit time-marching for time-dependent incompressible fluid flow. Zbl 1405.65129
Wang, Haijin; Liu, Yunxian; Zhang, Qiang; Shu, Chi-Wang
2019
Superconvergence of energy-conserving discontinuous Galerkin methods for linear hyperbolic equations. Zbl 1449.65250
Liu, Yong; Shu, Chi-Wang; Zhang, Mengping
2019
High order finite difference Hermite WENO schemes for the Hamilton-Jacobi equations on unstructured meshes. Zbl 1411.76111
Zheng, Feng; Shu, Chi-Wang; Qiu, Jianxian
2019
On new strategies to control the accuracy of WENO algorithms close to discontinuities. Zbl 1436.65095
Amat, Sergio; Ruiz, Juan; Shu, Chi-Wang
2019
Optimal energy-conserving discontinuous Galerkin methods for linear symmetric hyperbolic systems. Zbl 1452.65230
Fu, Guosheng; Shu, Chi-Wang
2019
High order arbitrary Lagrangian-Eulerian finite difference WENO scheme for Hamilton-Jacobi equations. Zbl 1473.65114
Li, Yue; Cheng, Juan; Xia, Yinhua; Shu, Chi-Wang
2019
Numerical solutions of stochastic PDEs driven by arbitrary type of noise. Zbl 1475.60112
Chen, Tianheng; Rozovskii, Boris; Shu, Chi-Wang
2019
Bounded and compact weighted essentially nonoscillatory limiters for discontinuous Galerkin schemes: triangular elements. Zbl 1452.76097
Mazaheri, Alireza; Shu, Chi-Wang; Perrier, Vincent
2019
Preface to the focused issue on fractional derivatives and general nonlocal models. Zbl 1449.00002
2019
Certified offline-free reduced basis (COFRB) methods for stochastic differential equations driven by arbitrary types of noise. Zbl 1440.65250
Liu, Yong; Chen, Tianheng; Chen, Yanlai; Shu, Chi-Wang
2019
Assessment of aeroacoustic resolution properties of DG schemes and comparison with DRP schemes. Zbl 1453.76064
Cheng, Ziqiang; Fang, Jinwei; Shu, Chi-Wang; Zhang, Mengping
2019
A new type of multi-resolution WENO schemes with increasingly higher order of accuracy. Zbl 1416.65286
Zhu, Jun; Shu, Chi-Wang
2018
A discontinuous Galerkin method for nonlinear parabolic equations and gradient flow problems with interaction potentials. Zbl 1380.65287
Sun, Zheng; Carrillo, José A.; Shu, Chi-Wang
2018
Superconvergence of discontinuous Galerkin method for scalar nonlinear hyperbolic equations. Zbl 1450.65116
Cao, Waixiang; Shu, Chi-Wang; Yang, Yang; Zhang, Zhimin
2018
Entropy stable high order discontinuous Galerkin methods for ideal compressible MHD on structured meshes. Zbl 1380.76162
Liu, Yong; Shu, Chi-Wang; Zhang, Mengping
2018
A provably positive discontinuous Galerkin method for multidimensional ideal magnetohydrodynamics. Zbl 1404.65184
Wu, Kailiang; Shu, Chi-Wang
2018
Implicit positivity-preserving high-order discontinuous Galerkin methods for conservation laws. Zbl 1380.65285
Qin, Tong; Shu, Chi-Wang
2018
Bound-preserving modified exponential Runge-Kutta discontinuous Galerkin methods for scalar hyperbolic equations with stiff source terms. Zbl 1422.65259
Huang, Juntao; Shu, Chi-Wang
2018
Third order implicit-explicit Runge-Kutta local discontinuous Galerkin methods with suitable boundary treatment for convection-diffusion problems with Dirichlet boundary conditions. Zbl 1448.65178
Wang, Haijin; Zhang, Qiang; Shu, Chi-Wang
2018
Optimal error estimates of the semidiscrete central discontinuous Galerkin methods for linear hyperbolic equations. Zbl 1383.65108
Liu, Yong; Shu, Chi-Wang; Zhang, Mengping
2018
On local conservation of numerical methods for conservation laws. Zbl 1410.65327
Shi, Cengke; Shu, Chi-Wang
2018
Bound-preserving high-order schemes for hyperbolic equations: survey and recent developments. Zbl 1412.65155
Shu, Chi-Wang
2018
Conservative high order positivity-preserving discontinuous Galerkin methods for linear hyperbolic and radiative transfer equations. Zbl 1407.65196
Ling, Dan; Cheng, Juan; Shu, Chi-Wang
2018
Discontinuous Galerkin methods for Maxwell’s equations in Drude metamaterials on unstructured meshes. Zbl 1462.65156
Shi, Cengke; Li, Jichun; Shu, Chi-Wang
2018
Positivity-preserving high-order schemes for conservation laws on arbitrarily distributed point clouds with a simple WENO limiter. Zbl 1414.65012
Du, Jie; Shu, Chi-Wang
2018
Discontinuous Galerkin methods for a kinetic model of self-organized dynamics. Zbl 1404.65168
Filbet, Francis; Shu, Chi-Wang
2018
Entropy stable high order discontinuous Galerkin methods with suitable quadrature rules for hyperbolic conservation laws. Zbl 1380.65253
Chen, Tianheng; Shu, Chi-Wang
2017
Optimal non-dissipative discontinuous Galerkin methods for Maxwell’s equations in Drude metamaterials. Zbl 1370.74143
Li, Jichun; Shi, Cengke; Shu, Chi-Wang
2017
Local discontinuous Galerkin method for the Keller-Segel chemotaxis model. Zbl 1384.92015
Li, Xingjie Helen; Shu, Chi-Wang; Yang, Yang
2017
A new troubled-cell indicator for discontinuous Galerkin methods for hyperbolic conservation laws. Zbl 1380.65262
Fu, Guosheng; Shu, Chi-Wang
2017
H(div) conforming and DG methods for incompressible Euler’s equations. Zbl 1433.76085
Guzmán, Johnny; Shu, Chi-Wang; Sequeira, Filánder A.
2017
Unconditional energy stability analysis of a second order implicit-explicit local discontinuous Galerkin method for the Cahn-Hilliard equation. Zbl 1383.65105
Song, Huailing; Shu, Chi-Wang
2017
Stability of the fourth order Runge-Kutta method for time-dependent partial differential equations. Zbl 1381.65079
Sun, Zheng; Shu, Chi-Wang
2017
Superconvergence of discontinuous Galerkin methods for 1-D linear hyperbolic equations with degenerate variable coefficients. Zbl 1382.65274
Cao, Waixiang; Shu, Chi-Wang; Zhang, Zhimin
2017
Numerical study on the convergence to steady state solutions of a new class of high order WENO schemes. Zbl 1380.76074
Zhu, Jun; Shu, Chi-Wang
2017
Finite difference Hermite WENO schemes for the Hamilton-Jacobi equations. Zbl 1415.65204
Zheng, Feng; Shu, Chi-Wang; Qiu, Jianxian
2017
Error estimates to smooth solutions of semi-discrete discontinuous Galerkin methods with quadrature rules for scalar conservation laws. Zbl 1361.65067
Huang, Juntao; Shu, Chi-Wang
2017
A second-order asymptotic-preserving and positivity-preserving discontinuous Galerkin scheme for the Kerr-Debye model. Zbl 1360.65235
Huang, Juntao; Shu, Chi-Wang
2017
Maximum-principle-satisfying space-time conservation element and solution element scheme applied to compressible multifluids. Zbl 1378.76086
Shen, Hua; Wen, Chih-Yung; Parsani, Matteo; Shu, Chi-Wang
2017
Stability analysis of the inverse Lax-Wendroff boundary treatment for high order central difference schemes for diffusion equations. Zbl 1361.65062
Li, Tingting; Shu, Chi-Wang; Zhang, Mengping
2017
Stability analysis and error estimates of Lax-Wendroff discontinuous Galerkin methods for linear conservation laws. Zbl 1373.65063
Sun, Zheng; Shu, Chi-Wang
2017
A phase-based interior penalty discontinuous Galerkin method for the Helmholtz equation with spatially varying wavenumber. Zbl 1439.65183
Lam, Chi Yeung; Shu, Chi-Wang
2017
Stability analysis and error estimates of local discontinuous Galerkin methods with implicit-explicit time-marching for the time-dependent fourth order PDEs. Zbl 1407.65204
Wang, Haijin; Zhang, Qiang; Shu, Chi-Wang
2017
Analysis of an embedded discontinuous Galerkin method with implicit-explicit time-marching for convection-diffusion problems. Zbl 1380.65261
Fu, Guosheng; Shu, Chi-Wang
2017
Runge-Kutta discontinuous Galerkin method with a simple and compact Hermite WENO limiter on unstructured meshes. Zbl 1488.65493
Zhu, Jun; Zhong, Xinghui; Shu, Chi-Wang; Qiu, Jianxian
2017
Positivity-preserving and symmetry-preserving Lagrangian schemes for compressible Euler equations in cylindrical coordinates. Zbl 1390.76473
Ling, Dan; Cheng, Juan; Shu, Chi-Wang
2017
Inverse Lax-Wendroff procedure for numerical boundary treatment of hyperbolic equations. Zbl 1366.65080
Shu, C.-W.; Tan, S.
2017
Bound-preserving high order finite volume schemes for conservation laws and convection-diffusion equations. Zbl 1372.65251
Shu, Chi-Wang
2017
Handbook on numerical methods for hyperbolic problems. Applied and modern issues. Zbl 1364.65001
2017
A simple bound-preserving sweeping technique for conservative numerical approximations. Zbl 1381.65087
Liu, Yuan; Cheng, Yingda; Shu, Chi-Wang
2017
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### Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2023-01-29T05:41:35 |
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https://www.aimsciences.org/article/doi/10.3934/steme.2022015?viewType=html
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Article Contents
Article Contents
# Design and implementation of multi-purpose quizzes to improve mathematics learning for transitional engineering students
• For students who are academically ineligible to enter a bachelor program in engineering but still want to upskill their knowledge in engineering, many universities provide an associate degree program in engineering to these students. The higher achievers from the associate degree program can transfer to a full degree program in engineering. Mathematics courses in such associate degree programs are often challenging to both the teachers and students due to various reasons. This paper presents a small part of a mathematics revitalization project on pedagogical adjustment to scaffold mathematics learning for students in an associate engineering program at Central Queensland University (CQU), a regional university in Australia, from 2018 to 2020. The design and implementation of the online multi-purpose quizzes (MPQ) to improve both the learning environment and outcomes for the engineering students from 2018 to 2020 are reported in this work. Statistically, the online MPQ empowered students to achieve their best possible outcomes by attempting the questions with time flexibility, on a confined set of topics, and with more chances of amending errors than the traditional written assessments. Hence, their performance in the online MPQ was consistently better than that in the written assignments in 2018-2020. The weaknesses of the online MPQ are also discussed.
Citation:
• Figure 1. Examples of MPQ for TM
Figure 2. Examples of online MPQ in TM
Figure 3. Part of the summary after completing one attempt to online MPQ in TM
Table 1. Weekly topics in TM prior to 2018
Week Topic 1 Basic algebra and operations 2 Geometry and trigonometric functions 3 Inequalities, functions and graphs 4 Factoring, quadratic functions 5 Oblique triangles and vectors 6 Ratio, proportion, graphs of trigonometric functions 7 Exponential and logarithmic functions 8 Systems of linear equations, matrices and determinants 9 The derivative 10 Applications of derivative 11 Integration and applications 12 Introduction to statistics
Table 2. Assessment scheme for TM prior to 2018
Assessment Topic Due Weight Written Assignment 1 Topics covered in Weeks 1-4 Week 5 25% Written Assignment 2 Topics covered in Weeks 5-8 Week 9 25% Written Assignment 3 Topics covered in Weeks 9-11 Week 12 10% Exanimation All topics Week 14 40%
Table 3. The new schedule of weekly topics covered in TM in 2018 and 2019
Week Topic 1 Basic Algebra (Ⅰ) 2 Basic Algebra (Ⅱ) and Basic Geometry 3 Inequalities and Sequences 4 Functions and Graphs 5 Polynomial Functions 6 Exponential and Logarithmic Functions 7 Triangles and Trigonometry 8 Trigonometric and Hyperbolic Functions 9 Essentials of Differentiation 10 Applications of Differentiation 11 Integration 12 Applications of Integration
Table 4. New assessment scheme for TM in 2018 and 2019
Assessment Topic Due Weight Online quizzes Algebra, inequalities, sequences, linear & quadratic functions covered in Weeks 1-5 Week 6 20% Written assignment 1 Triangles, exponential, logarithmic, trigonometric functions covered in Weeks 6-8 Week 9 20% Written assignment 2 Calculus covered in Weeks 9-11 Week 12 20% Exanimation (invigilated) All topics Week 14 40%
Table 5. Statistics of results from the first two assessments in Term 1 of 2018 and 2019
Year Number of students OQ WA1 Mean SD Mean SD 2018 29 18.345 3.687 15.862 3.729 2019 26 18.923 1.294 14.827 3.564
Table 6. The t-test results between OC and WA1 for TM in 2018 and 2019
Year d.f. Critical t-value (α = 0.025) t-value for OQ-WA1 2018 56 ±2.003 2.550 2019 50 ±2.009 5.508
Table 7. Statistics of results from OQ, WA1 and WA2 for TM in Term 2 of 2020
Number of students OQ WA1 WA2 Mean SD Mean SD Mean SD 21 19.476 0.981 17.047 3.232 15.690 3.376
Table 8. The t-test results between OQ and WA1 or WA2 for TM in Term 2 of 2020
Year d.f. Critical t-value (α = 0.025) t-value for OQ-WA1 t-value for OQ-WA2 2020 40 ±2.021 3.296 4.947
Table 9. The t-test results between OQ for TM in 2018 and OQ in 2019 and 2020
Year d.f. Critical t-value (α = 0.025) t-value for Q-Q 2018-2019 53 ±2.006 -0.758 2018-2020 48 ±2.011 -1.368
• [1] Mestre, J., Hart, D.M., Rath, K.A. and Dufresne, R., The effect of web-based homework on test performance in large enrollment introductory physics courses. Journal of Computers in Mathematics and Science Teaching, 2002, 21(3): 229-251. [2] Cole, R.S. and Todd, J.B., Effects of web-based multimedia homework with immediate rich feedback on student learning in general chemistry. Journal of Chemical Education, 2003, 80(11): 1338-1343. http://doi.org/10.1021/ed080p1338doi: 10.1021/ed080p1338. [3] Beatty, I.D. and Gerace, W.J., Technology-enhanced formative assessment: A research based pedagogy for teaching science with classroom response technology. Journal of Science Education and Technology, 2009, 18: 146-162. http://doi.org/10.1007/s10956-008-9140-4doi: 10.1007/s10956-008-9140-4. [4] Cohen, D. and Sasson, I., Online quizzes in a virtual learning environment as a tool for formative assessment. Journal of Technology and Science Education, 2016, 6(3): 188-208. http://doi.org/10.3926/jotse.217doi: 10.3926/jotse.217. [5] Dizon, A.C.O., An, S., Lubguban, A.A. and Suppes, G.J., Online quiz methods for remedial learning in chemical engineering. Education for Chemical Engineers, 2018, 23: 18-24. http://doi.org/10.1016/j.ece.2018.04.001doi: 10.1016/j.ece.2018.04.001. [6] Gamage, S.H.P.W., Ayres, J.R., Behrend, M.B. et al., Optimising Moodle quizzes for online assessments. International Journal of STEM Education, 2019, 6: 27. https://doi.org/10.1186/s40594-019-0181-4doi: 10.1186/s40594-019-0181-4. [7] Dimas, D.J., Jabbari, F. and Billimek, J., Using recorded lectures and low stakes online quizzes to improve learning efficiency in undergraduate engineering courses, in ASEE Annual Conference and Exposition, 2014. [8] Tisdell, C.C., Embedding opportunities for participation and feedback in large mathematics lectures via audience response systems. STEM Education, 2021, 1(2): 75-91. https://doi.org/10.3934/steme.2021006doi: 10.3934/steme.2021006. [9] Romero, E., García, L. and Ceamanos, J., Moodle and Socrative quizzes as formative aids on theory teaching in a chemical engineering subject. Education for Chemical Engineers, 2021, 36: 54-64. https://doi.org/10.1016/j.ece.2021.03.001doi: 10.1016/j.ece.2021.03.001. [10] Martins, S.G., Weekly online quizzes to a mathematics course for engineering students. Teaching Mathematics and its Applications: An international journal of the IMA, 2017, 36 (1): 56-63. https://doi.org/10.1093/teamat/hrw011doi: 10.1093/teamat/hrw011. [11] Notaroš, B.M., McCullough, R., Athalye, P.S. and Maclejewski, A.A., New partially flipped electromagnetics classroom approach using conceptual questions. International Journal of Engineering Education, 2019, 35(4): 1215-1223. [12] Gyllen, J.G., Stahovich, T.F., Mayer, R.E., Entezari, N. and Darvishzadeh, A., Priming productive study strategies with preparatory quizzes in an engineering course. Applied Cognitive Psychology, 2021, 35(1): 169-180. https://doi.org/10.1002/acp.3750doi: 10.1002/acp.3750. [13] Torun, A.R., The effect of weekly distributed mathematics homework and quizzes on the learning performance of engineering students. International Journal of Engineering Education, 2019, 35(5): 1561-1565. [14] Gero, A. and Stav, Y., Summative assessment based on two-tier multiple-choice questions: Item discrimination and engineering students' and teachers' attitudes. International Journal of Engineering Education, 2021, 37(3): 830-840. [15] Sun, G., Cui, T., Guo, W., Beydoun, G., Xu, D. and Shen, J., Micro learning adaptation in MOOC: A software as a service and a personalized learner model. Lecture Notes in Computer Science, 2015, 9412: 174-184. https://doi.org/10.1007/978-3-319-25515-6_16doi: 10.1007/978-3-319-25515-6_16. [16] Garshasbi, S., Yecies, B. and Shen. J., Microlearning and computer-supported collaborative learning: An agenda towards a comprehensive online learning system. STEM Education, 2021, 1(4): 225-255. https://doi.org/10.3934/steme.2021016doi: 10.3934/steme.2021016. [17] Guo, W., Li, W. and Tisdell, C.C., Effective pedagogy of guiding undergraduate engineering students solving first-order ordinary differential equations. Mathematics, 2021, 9(14): 1623. https://doi.org/10.3390/math9141623.doi: 10.3390/math9141623.
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| 2022-12-07T02:36:12 |
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http://smai-jcm.cedram.org/smai-jcm-bin/item?id=SMAI-JCM_2018__4__259_0
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With cedram.org version française Home Presentation Advanced Search All online articles Latest articles Search for an article Table of contents for this volume | Previous article | Next article Jean-Baptiste BelletMultiresolution greedy algorithm dedicated to reflective tomographySMAI-Journal of computational mathematics, 4 (2018), p. 259-296, doi: 10.5802/smai-jcm.35 Article PDF Class. Math.: 78A97, 94A12, 65B99, 65Y20Keywords: Computational optics, reconstruction, acceleration, complexity AbstractReflective tomography recovers the surfaces of a scene to be imaged, from optical images: a tomographic algorithm computes a full volumic reconstruction and then the surfaces are extracted from this reconstruction. For better performance, we would like to avoid computing accurately the full reconstruction, and we want to focus computations on the sought surfaces. For that purpose we propose an iterative multiresolution process. The initialization computes a coarse reconstruction, and the iterations refines it. To identify the voxels to be refined, we take advantage of the asymptotic behaviour of the reconstruction, with respect to its cut-off frequency: it discriminates the surfaces to be extracted. By the way the proposed algorithm is greedy: each iteration maximizes the accumulated intensity of the selected voxels, with prescribed volume. The combination of the complexity analysis and the numerical results shows that this novel approach succeeds in reconstructing surfaces and is relatively efficient compared with the standard method. These works pave the way towards accelerated algorithms in reflective tomography. They can be extended to a general class of problems concerning the determination of asymptotically discriminated sets, what is related to the computation of singular support of distributions. Bibliography[1] Jean-Baptiste Bellet, “Analyse asymptotique et géométrique de la tomographie réflective”, $<$hal-01571707$>$, 2017 [2] Jean-Baptiste Bellet & Gérard Berginc, “Reflective Filtered Backprojection”, Comptes rendus - Mathématique 354 (2016), p. 960-964 [3] I. Berechet & G. Berginc, Advanced algorithms for identifying targets from a three-dimensional reconstruction of sparse 3D Ladar data, in G. Berginc, ed., Optical Complex Systems: OCS11, 81720Z, Proc. of SPIE, 2011 [4] Stefan Berechet, Ion Berechet, Jean-Baptiste Bellet & Gérard Berginc, “Procédé de discrimination et d’identification par imagerie 3D d’objets d’une scène”, Patent WO2016097168 A1 2015 [5] G. Berginc, J.-B. Bellet, I. Berechet & S. Berechet, Optical 3D imaging and visualization of concealed objects, in Proc. SPIE, 2016 [6] G. Berginc & M. Jouffroy, Simulation of 3D laser systems, in Geoscience and Remote Sensing Symposium, 2009 IEEE International, IGARSS 2009, IEEE, 2009, p. 440-444 [7] G. Berginc & M. Jouffroy, “Simulation of 3D laser imaging”, PIERS Online 6 (2010) no. 5, p. 415-419 [8] Gérard Berginc, “Scattering models for 1-D–2-D–3-D laser imagery”, Optical Engineering 56 (2016) no. 3 Article[9] David T. Gering & W.M. Wells, Object modeling using tomography and photography, in Multi-View Modeling and Analysis of Visual Scenes, 1999.(MVIEW’99) Proceedings. IEEE Workshop on, IEEE, 1999, p. 11-18 [10] Henri Gouraud, “Continuous shading of curved surfaces”, IEEE transactions on computers 100 (1971) no. 6, p. 623-629 [11] Markus Henriksson, Tomas Olofsson, Christina Grönwall, Carl Brännlund & Lars Sjöqvist, Optical reflectance tomography using TCSPC laser radar, in Proc. SPIE, 2012 [12] Berthold Horn, Robot vision, MIT press, 1986 [13] F.K. Knight, S.R. Kulkarni, R.M. Marino & J.K. Parker, “Tomographic Techniques Applied to Laser Radar Reflective Measurements”, Lincoln Laboratory Journal 2 (1989) no. 2, p. 143-160 [14] Aldo Laurentini, “The visual hull concept for silhouette-based image understanding”, IEEE Transactions on pattern analysis and machine intelligence 16 (1994) no. 2, p. 150-162 [15] Charles Soussen & Jérôme Idier, 3D reconstruction of localized objects from radiographs and based on multiresolution and sparsity, in IEEE International Conference on Image Processing, IEEE, 2005, p. 744-747 [16] Greg Turk & Marc Levoy, Zippered polygon meshes from range images, in Proceedings of the 21st annual conference on Computer graphics and interactive techniques, ACM, 1994, p. 311-318 [17] J.W. Wallis & T.R. Miller, “Three-Dimensional Display in Nuclear Medicine and Radiology”, The Journal of Nuclear Medicine (1991), p. 534-546 © 2015SMAI Journal of Computational Mathematics ISSN 2426-8399 Papers are published under the licence Creative Commons CC BY-NC-ND 3.0
| 2019-02-18T22:12:27 |
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http://dlmf.nist.gov/errata/
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# Errata
The following corrections and other changes have been made in the DLMF, and are pending for the Handbook of Mathematical Functions. The Editors thank the users who have contributed to the accuracy of the DLMF Project by submitting reports of possible errors. For confirmed errors, the Editors have made the corrections listed here. Printable errata .
## Version 1.0.14 (December 21, 2016)
Equation (8.18.3)
8.18.3 $\mathop{I_{x}\/}\nolimits\!\left(a,b\right)=\frac{\mathop{\Gamma\/}\nolimits\!% \left(a+b\right)}{\mathop{\Gamma\/}\nolimits\!\left(a\right)}\left(\sum_{k=0}^% {n-1}d_{k}F_{k}+\mathop{O\/}\nolimits\!\left(a^{-n}\right)F_{0}\right).$
The range of $x$ was extended to include $1$. Previously this equation appeared without the order estimate as $\mathop{I_{x}\/}\nolimits\!\left(a,b\right)\sim\frac{\mathop{\Gamma\/}% \nolimits\!\left(a+b\right)}{\mathop{\Gamma\/}\nolimits\!\left(a\right)}\sum_{% k=0}^{\infty}d_{k}F_{k}$.
Reported 2016-11-22.
Equation (17.9.2)
The entry $q/c$ in the first row of $\mathop{{{}_{3}\phi_{1}}\/}\nolimits\!\left({q^{-n},b,q/c\atop bq^{1-n}/c};q,z% /c\right)$ was replaced by $q/z$. The equation now reads
17.9.2 $\mathop{{{}_{2}\phi_{1}}\/}\nolimits\!\left({q^{-n},b\atop c};q,z\right)=\frac% {\left(c/b;q\right)_{n}}{\left(c;q\right)_{n}}b^{n}\mathop{{{}_{3}\phi_{1}}\/}% \nolimits\!\left({q^{-n},b,q/z\atop bq^{1-n}/c};q,z/c\right),$
Reported 2016-08-30 by Xinrong Ma.
Figures 36.3.9, 36.3.10, 36.3.11, 36.3.12
Scales were corrected in all figures. The interval $-8.4\leq\frac{x-y}{\sqrt{2}}\leq 8.4$ was replaced by $-12.0\leq\frac{x-y}{\sqrt{2}}\leq 12.0$ and $-12.7\leq\frac{x+y}{\sqrt{2}}\leq 4.2$ replaced by $-18.0\leq\frac{x+y}{\sqrt{2}}\leq 6.0$. All plots and interactive visualizations were regenerated to improve image quality.
Reported 2016-09-12 by Dan Piponi.
Figures 36.3.18, 36.3.19, 36.3.20, 36.3.21
The scaling error reported on 2016-09-12 by Dan Piponi also applied to contour and density plots for the phase of the hyperbolic umbilic canonical integrals. Scales were corrected in all figures. The interval $-8.4\leq\frac{x-y}{\sqrt{2}}\leq 8.4$ was replaced by $-12.0\leq\frac{x-y}{\sqrt{2}}\leq 12.0$ and $-12.7\leq\frac{x+y}{\sqrt{2}}\leq 4.2$ replaced by $-18.0\leq\frac{x+y}{\sqrt{2}}\leq 6.0$. All plots and interactive visualizations were regenerated to improve image quality.
Reported 2016-09-28.
Other Changes
• A number of changes were made with regard to fractional integrals and derivatives. In §1.15(vi) a reference to Miller and Ross (1993) was added, the fractional integral operator of order $\alpha$ was more precisely identified as the Riemann-Liouville fractional integral operator of order $\alpha$, and a paragraph was added below (1.15.50) to generalize (1.15.47). In §1.15(vii) the sentence defining the fractional derivative was clarified. In §2.6(iii) the identification of the Riemann-Liouville fractional integral operator was made consistent with §1.15(vi).
• Changes to §8.18(ii)–§8.11(v): A sentence was added in §8.18(ii) to refer to Nemes and Olde Daalhuis (2016). Originally §8.11(iii) was applicable for real variables $a$ and $x=\lambda a$. It has been extended to allow for complex variables $a$ and $z=\lambda a$ (and we have replaced $x$ with $z$ in the subsection heading and in Equations (8.11.6) and (8.11.7)). Also, we have added two paragraphs after (8.11.9) to replace the original paragraph that appeared there. Furthermore, the interval of validity of (8.11.6) was increased from $0<\lambda<1$ to the sector $0<\lambda<1,|\mathop{\mathrm{ph}\/}\nolimits a|\leq\frac{\pi}{2}-\delta$, and the interval of validity of (8.11.7) was increased from $\lambda>1$ to the sector $\lambda>1,|\mathop{\mathrm{ph}\/}\nolimits a|\leq\frac{3\pi}{2}-\delta$. A paragraph with reference to Nemes (2016) has been added in §8.11(v), and the sector of validity for (8.11.12) was increased from $|\mathop{\mathrm{ph}\/}\nolimits z|\leq\pi-\delta$ to $|\mathop{\mathrm{ph}\/}\nolimits z|\leq 2\pi-\delta$.
• Two new sections §13.6(vii) and §13.18(vi) were added to note the relationship of the Kummer and Whittaker functions to various forms of the Coulomb functions. A sentence was added in both §13.10(vi) and §13.23(v) noting that certain generalized orthogonality can be expressed in terms of Kummer functions.
• Four of the terms in (14.15.23) were rewritten for improved clarity.
• In §15.6 it was noted that (15.6.8) can be rewritten as a fractional integral.
• In applying changes in Version 1.0.12 to (16.15.3), an editing error was made; it has been corrected.
• In §34.1, the reference for Clebsch-Gordan coefficients, Condon and Shortley (1935), was replaced by Edmonds (1974) and Rotenberg et al. (1959). The references for $\mathit{3j}$, $\mathit{6j}$, $\mathit{9j}$ symbols were made more precise.
• Images in Figures 36.3.1, 36.3.2, 36.3.3, 36.3.4, 36.3.5, 36.3.6, 36.3.7, 36.3.8 and Figures 36.3.13, 36.3.14, 36.3.15, 36.3.16, 36.3.17 were resized for consistency.
• Meta.Numerics (Web Site) was added to the Software Index.
## Version 1.0.13 (September 16, 2016)
Other Changes
• In applying changes in Version 1.0.12 to (13.9.16), an editing error was made; it has been corrected.
## Version 1.0.12 (September 9, 2016)
Equations (25.11.6), (25.11.19), and (25.11.20)
Originally all six integrands in these equations were incorrect because their numerators contained the function $\mathop{\widetilde{B}_{2}\/}\nolimits\!\left(x\right)$. The correct function is $\frac{\mathop{\widetilde{B}_{2}\/}\nolimits\!\left(x\right)-\mathop{B_{2}\/}% \nolimits}{2}$. The new equations are:
25.11.6 $\mathop{\zeta\/}\nolimits\!\left(s,a\right)=\frac{1}{a^{s}}\left(\frac{1}{2}+% \frac{a}{s-1}\right)-\frac{s(s+1)}{2}\int_{0}^{\infty}\frac{\mathop{\widetilde% {B}_{2}\/}\nolimits\!\left(x\right)-\mathop{B_{2}\/}\nolimits}{(x+a)^{s+2}}% \mathrm{d}x,$ $s\neq 1$, $\Re{s}>-1$, $a>0$.
Reported 2016-05-08 by Clemens Heuberger.
25.11.19 $\mathop{\zeta\/}\nolimits'\!\left(s,a\right)=-\frac{\mathop{\ln\/}\nolimits a}% {a^{s}}\left(\frac{1}{2}+\frac{a}{s-1}\right)-\frac{a^{1-s}}{(s-1)^{2}}+\frac{% s(s+1)}{2}\int_{0}^{\infty}\frac{(\mathop{\widetilde{B}_{2}\/}\nolimits\!\left% (x\right)-\mathop{B_{2}\/}\nolimits)\mathop{\ln\/}\nolimits\!\left(x+a\right)}% {(x+a)^{s+2}}\mathrm{d}x-\frac{(2s+1)}{2}\int_{0}^{\infty}\frac{\mathop{% \widetilde{B}_{2}\/}\nolimits\!\left(x\right)-\mathop{B_{2}\/}\nolimits}{(x+a)% ^{s+2}}\mathrm{d}x,$ $\Re{s}>-1$, $s\neq 1$, $a>0$.
Reported 2016-06-27 by Gergő Nemes.
25.11.20 $(-1)^{k}{\mathop{\zeta\/}\nolimits^{(k)}}\!\left(s,a\right)=\frac{(\mathop{\ln% \/}\nolimits a)^{k}}{a^{s}}\left(\frac{1}{2}+\frac{a}{s-1}\right)+k!a^{1-s}% \sum_{r=0}^{k-1}\frac{(\mathop{\ln\/}\nolimits a)^{r}}{r!(s-1)^{k-r+1}}-\frac{% s(s+1)}{2}\int_{0}^{\infty}\frac{(\mathop{\widetilde{B}_{2}\/}\nolimits\!\left% (x\right)-\mathop{B_{2}\/}\nolimits)(\mathop{\ln\/}\nolimits\!\left(x+a\right)% )^{k}}{(x+a)^{s+2}}\mathrm{d}x+\frac{k(2s+1)}{2}\int_{0}^{\infty}\frac{(% \mathop{\widetilde{B}_{2}\/}\nolimits\!\left(x\right)-\mathop{B_{2}\/}% \nolimits)(\mathop{\ln\/}\nolimits\!\left(x+a\right))^{k-1}}{(x+a)^{s+2}}% \mathrm{d}x-\frac{k(k-1)}{2}\int_{0}^{\infty}\frac{(\mathop{\widetilde{B}_{2}% \/}\nolimits\!\left(x\right)-\mathop{B_{2}\/}\nolimits)(\mathop{\ln\/}% \nolimits\!\left(x+a\right))^{k-2}}{(x+a)^{s+2}}\mathrm{d}x,$ $\Re{s}>-1$, $s\neq 1$, $a>0$.
Reported 2016-06-27 by Gergő Nemes.
Other Changes
• The symbol $\sim$ is used for two purposes in the DLMF, in some cases for asymptotic equality and in other cases for asymptotic expansion, but links to the appropriate definitions were not provided. In this release changes have been made to provide these links.
• A short paragraph dealing with asymptotic approximations that are expressed in terms of two or more Poincaré asymptotic expansions has been added in §2.1(iii) below (2.1.16).
• Because (2.11.4) is not an asymptotic expansion, the symbol $\sim$ that was used originally is incorrect and has been replaced with $\approx$, together with a slight change of wording.
• Originally (13.9.16) was expressed in term of asymptotic symbol $\sim$. As a consequence of the use of the $\mathop{O\/}\nolimits$ order symbol on the right hand side, $\sim$ was replaced by $=$.
• In (13.2.9) and (13.2.10) there were clarifications made in the conditions on the parameter $a$ in $\mathop{U\/}\nolimits\!\left(a,b,z\right)$ of those equations.
• Originally (14.15.23) used $f(x)$ to represent both $\mathop{U\/}\nolimits\!\left(-c,x\right)$ and $\mathop{\overline{U}\/}\nolimits\!\left(-c,x\right)$. This has been replaced by two equations giving explicit definitions for the two envelope functions. Some slight changes in wording were needed to make this clear to readers.
• The title for §17.9 was changed from Transformations of Higher $\mathop{{{}_{r}\phi_{r}}\/}\nolimits$ Functions to Further Transformations of $\mathop{{{}_{r+1}\phi_{r}}\/}\nolimits$ Functions.
• A number of additions and changes have been made to the metadata in Chapter 25 Zeta and Related Functions to reflect new and changed references as well as to how some equations have been derived.
• Bibliographic citations, clarifications, typographical corrections and added or modified sentences appear in §§18.15(i) and 18.16(ii).
## Version 1.0.11 (June 8, 2016)
Figure 4.3.1
This figure was rescaled, with symmetry lines added, to make evident the symmetry due to the inverse relationship between the two functions.
Reported 2015-11-12 by James W. Pitman.
Equation (9.7.17)
Originally the constraint, $\frac{2}{3}\pi\leq|\mathop{\mathrm{ph}\/}\nolimits z|<\pi$, was written incorrectly as $\frac{2}{3}\pi\leq|\mathop{\mathrm{ph}\/}\nolimits z|\leq\pi$. Also, the equation was reformatted to display the constraints in the equation instead of in the text.
Reported 2014-11-05 by Gergő Nemes.
Equation (10.32.13)
Originally the constraint, $|\mathop{\mathrm{ph}\/}\nolimits z|<\frac{1}{2}\pi$, was incorrectly written as, $|\mathop{\mathrm{ph}\/}\nolimits z|<\pi$.
Reported 2015-05-20 by Richard Paris.
Equation (10.40.12)
Originally the third constraint $\pi\leq|\mathop{\mathrm{ph}\/}\nolimits z|<\frac{3}{2}\pi$ was incorrectly written as $\pi\leq|\mathop{\mathrm{ph}\/}\nolimits z|\leq\frac{3}{2}\pi$.
Reported 2014-11-05 by Gergő Nemes.
Equation (23.18.7)
23.18.7 $s(d,c)=\sum_{r=1}^{c-1}\frac{r}{c}\left(\frac{dr}{c}-\left\lfloor\frac{dr}{c}% \right\rfloor-\frac{1}{2}\right),$ $c>0$.
Originally the sum $\sum_{r=1}^{c-1}$ was written with an additional condition on the summation, that $\left(r,c\right)=1$. This additional condition was incorrect and has been removed.
Reported 2015-10-05 by Howard Cohl and Tanay Wakhare.
Equations (28.28.21) and (28.28.22)
28.28.21 $\dfrac{4}{\pi}\int_{0}^{\pi/2}\mathcal{C}^{(j)}_{2\ell+1}(2hR)\mathop{\cos\/}% \nolimits\!\left((2\ell+1)\phi\right)\mathop{\mathrm{ce}_{2m+1}\/}\nolimits\!% \left(t,h^{2}\right)\mathrm{d}t=(-1)^{\ell+m}A^{2m+1}_{2\ell+1}(h^{2})\mathop{% {\mathrm{Mc}^{(j)}_{2m+1}}\/}\nolimits\!\left(z,h\right),$
28.28.22 $\\ \dfrac{4}{\pi}\int_{0}^{\pi/2}\mathcal{C}^{(j)}_{2\ell+1}(2hR)\mathop{\sin\/}% \nolimits\!\left((2\ell+1)\phi\right)\mathop{\mathrm{se}_{2m+1}\/}\nolimits\!% \left(t,h^{2}\right)\mathrm{d}t=(-1)^{\ell+m}B^{2m+1}_{2\ell+1}(h^{2})\mathop{% {\mathrm{Ms}^{(j)}_{2m+1}}\/}\nolimits\!\left(z,h\right),$
Originally the prefactor $\frac{4}{\pi}$ and upper limit of integration $\pi/2$ in these two equations were given incorrectly as $\frac{2}{\pi}$ and $\pi$.
Reported 2015-05-20 by Ruslan Kabasayev
Other Changes
• In §1.2(i), a sentence was added after (1.2.1) to refer to (1.2.6) as the definition of the binomial coefficient $\binom{z}{k}$ when $z$ is complex. As a notational clarification, wherever $n$ appeared originally in (1.2.6)–(1.2.9), it was replaced by $z$.
• It was reported by Nico Temme on 2015-02-28 that the asymptotic formula for $\mathop{\mathrm{Ln}\/}\nolimits\mathop{\Gamma\/}\nolimits\!\left(z+h\right)$ given in (5.11.8) is valid for $h(\in\mathbb{C})$; originally it was unnecessarily restricted to $[0,1]$.
• A new paragraph with several new equations and a new reference has been added at the end of §13.8(iii) to provide asymptotic expansions for Kummer functions $\mathop{U\/}\nolimits\!\left(a,b,z\right)$ and $\mathop{{\mathbf{M}}\/}\nolimits\!\left(a,b,z\right)$ as $a\to\infty$ in $|\mathop{\mathrm{ph}\/}\nolimits a|\leq\pi-\delta$ and $b$ and $z$ fixed.
• Because of the use of the $\mathop{O\/}\nolimits$ order symbol on the right-hand side, the asymptotic expansion (18.15.22) for the generalized Laguerre polynomial $\mathop{L^{(\alpha)}_{n}\/}\nolimits\!\left(\nu x\right)$ was rewritten as an equality.
• The entire section §27.20 was replaced.
• Clarifications, typographic corrections, added or modified sentences appear in §§1.2(i), 1.10(i), 4.6(ii), 5.11(i), (11.11.1), (11.11.9), (21.5.7), and (27.14.7).
## Version 1.0.10 (August 7, 2015)
Section 4.43
The first paragraph has been rewritten to correct reported errors. The new version is reproduced here.
Let $p(\neq 0)$ and $q$ be real constants and
4.43.1 $\displaystyle A$ $\displaystyle=\left(-\tfrac{4}{3}p\right)^{1/2},$ $\displaystyle B$ $\displaystyle=\left(\tfrac{4}{3}p\right)^{1/2}.$
The roots of
4.43.2 $z^{3}+pz+q=0$
are:
1. (a)
$A\mathop{\sin\/}\nolimits a$, $A\mathop{\sin\/}\nolimits\!\left(a+\frac{2}{3}\pi\right)$, and $A\mathop{\sin\/}\nolimits\!\left(a+\frac{4}{3}\pi\right)$, with $\mathop{\sin\/}\nolimits\!\left(3a\right)=4q/A^{3}$, when $4p^{3}+27q^{2}\leq 0$.
2. (b)
$A\mathop{\cosh\/}\nolimits a$, $A\mathop{\cosh\/}\nolimits\!\left(a+\frac{2}{3}\pi\mathrm{i}\right)$, and $A\mathop{\cosh\/}\nolimits\!\left(a+\frac{4}{3}\pi\mathrm{i}\right)$, with $\mathop{\cosh\/}\nolimits\!\left(3a\right)=-4q/A^{3}$, when $p<0$, $q<0$, and $4p^{3}+27q^{2}>0$.
3. (c)
$B\mathop{\sinh\/}\nolimits a$, $B\mathop{\sinh\/}\nolimits\!\left(a+\frac{2}{3}\pi\mathrm{i}\right)$, and $B\mathop{\sinh\/}\nolimits\!\left(a+\frac{4}{3}\pi\mathrm{i}\right)$, with $\mathop{\sinh\/}\nolimits\!\left(3a\right)=-4q/B^{3}$, when $p>0$.
Note that in Case (a) all the roots are real, whereas in Cases (b) and (c) there is one real root and a conjugate pair of complex roots. See also §1.11(iii).
Reported 2014-10-31 by Masataka Urago.
Equation (9.10.18)
9.10.18 $\mathop{\mathrm{Ai}\/}\nolimits\!\left(z\right)=\frac{3z^{5/4}{\mathrm{e}^{-(2% /3)z^{3/2}}}}{4\pi}\*\int_{0}^{\infty}\frac{t^{-3/4}{\mathrm{e}^{-(2/3)t^{3/2}% }}\mathop{\mathrm{Ai}\/}\nolimits\!\left(t\right)}{z^{3/2}+t^{3/2}}\mathrm{d}t.$
The original equation taken from Schulten et al. (1979) was incorrect.
Reported 2015-03-20 by Walter Gautschi.
Equation (9.10.19)
9.10.19 $\mathop{\mathrm{Bi}\/}\nolimits\!\left(x\right)=\frac{3x^{5/4}{\mathrm{e}^{(2/% 3)x^{3/2}}}}{2\pi}\*\pvint_{0}^{\infty}\frac{t^{-3/4}{\mathrm{e}^{-(2/3)t^{3/2% }}}\mathop{\mathrm{Ai}\/}\nolimits\!\left(t\right)}{x^{3/2}-t^{3/2}}\mathrm{d}t.$
The original equation taken from Schulten et al. (1979) was incorrect.
Reported 2015-03-20 by Walter Gautschi.
Equation (10.17.14)
10.17.14 $\left|R_{\ell}^{\pm}(\nu,z)\right|\leq 2|a_{\ell}(\nu)|\mathop{\mathcal{V}_{z,% \pm\mathrm{i}\infty}\/}\nolimits\!\left(t^{-\ell}\right)\*\mathop{\exp\/}% \nolimits\left(|\nu^{2}-\tfrac{1}{4}|\mathop{\mathcal{V}_{z,\pm\mathrm{i}% \infty}\/}\nolimits\!\left(t^{-1}\right)\right)$
Originally the factor $\mathop{\mathcal{V}_{z,\pm\mathrm{i}\infty}\/}\nolimits\!\left(t^{-1}\right)$ in the argument to the exponential was written incorrectly as $\mathop{\mathcal{V}_{z,\pm\mathrm{i}\infty}\/}\nolimits\!\left(t^{-\ell}\right)$.
Reported 2014-09-27 by Gergő Nemes.
Equation (10.19.11)
10.19.11 $\mathop{Q_{3}\/}\nolimits\!\left(a\right)=\tfrac{549}{28000}a^{8}-\tfrac{1\;10% 767}{6\;93000}a^{5}+\tfrac{79}{12375}a^{2}$
Originally the first term on the right-hand side of this equation was written incorrectly as $-\tfrac{549}{28000}a^{8}$.
Reported 2015-03-16 by Svante Janson.
Equation (13.2.7)
13.2.7 $\mathop{U\/}\nolimits\!\left(-m,b,z\right)=(-1)^{m}{\left(b\right)_{m}}\mathop% {M\/}\nolimits\!\left(-m,b,z\right)=(-1)^{m}\sum_{s=0}^{m}\binom{m}{s}{\left(b% +s\right)_{m-s}}(-z)^{s}$
The equality $\mathop{U\/}\nolimits\!\left(-m,b,z\right)=(-1)^{m}{\left(b\right)_{m}}\mathop% {M\/}\nolimits\!\left(-m,b,z\right)$ has been added to the original equation to express an explicit connection between the two standard solutions of Kummer’s equation. Note also that the notation $a=-n$ has been changed to $a=-m$.
Reported 2015-02-10 by Adri Olde Daalhuis.
Equation (13.2.8)
13.2.8 $\mathop{U\/}\nolimits\!\left(a,a+n+1,z\right)=\frac{(-1)^{n}{\left(1-a-n\right% )_{n}}}{z^{a+n}}\*\mathop{M\/}\nolimits\!\left(-n,1-a-n,z\right)=z^{-a}\sum_{s% =0}^{n}\binom{n}{s}{\left(a\right)_{s}}z^{-s}$
The equality $\mathop{U\/}\nolimits\!\left(a,a+n+1,z\right)=\frac{(-1)^{n}{\left(1-a-n\right% )_{n}}}{z^{a+n}}\*\mathop{M\/}\nolimits\!\left(-n,1-a-n,z\right)$ has been added to the original equation to express an explicit connection between the two standard solutions of Kummer’s equation.
Reported 2015-02-10 by Adri Olde Daalhuis.
Equation (13.2.10)
13.2.10 $\mathop{U\/}\nolimits\!\left(-m,n+1,z\right)=(-1)^{m}{\left(n+1\right)_{m}}% \mathop{M\/}\nolimits\!\left(-m,n+1,z\right)=(-1)^{m}\sum_{s=0}^{m}\binom{m}{s% }{\left(n+s+1\right)_{m-s}}(-z)^{s}$
The equality $\mathop{U\/}\nolimits\!\left(-m,n+1,z\right)=(-1)^{m}{\left(n+1\right)_{m}}\*% \mathop{M\/}\nolimits\!\left(-m,n+1,z\right)$ has been added to the original equation to express an explicit connection between the two standard solutions of Kummer’s equation. Note also that the notation $a=-m,m=0,1,2,\ldots$ has been introduced.
Reported 2015-02-10 by Adri Olde Daalhuis.
Equation (18.33.3)
18.33.3 $\phi_{n}^{*}(z)=z^{n}\overline{\phi_{n}({\overline{z}^{-1}})}={\kappa_{n}}+% \sum_{\ell=1}^{n}\overline{\kappa}_{n,n-\ell}z^{\ell}$
Originally this equation was written incorrectly as $\phi_{n}^{*}(z)={\kappa_{n}}z^{n}+\sum_{\ell=1}^{n}\overline{\kappa}_{n,n-\ell% }z^{n-\ell}$. Also, the equality $\phi_{n}^{*}(z)=z^{n}\overline{\phi_{n}({\overline{z}^{-1}})}$ has been added.
Reported 2014-10-03 by Roderick Wong.
Equation (34.7.4)
34.7.4 $\begin{pmatrix}j_{13}&j_{23}&j_{33}\\ m_{13}&m_{23}&m_{33}\end{pmatrix}\begin{Bmatrix}j_{11}&j_{12}&j_{13}\\ j_{21}&j_{22}&j_{23}\\ j_{31}&j_{32}&j_{33}\end{Bmatrix}=\sum_{m_{r1},m_{r2},r=1,2,3}\begin{pmatrix}j% _{11}&j_{12}&j_{13}\\ m_{11}&m_{12}&m_{13}\end{pmatrix}\*\begin{pmatrix}j_{21}&j_{22}&j_{23}\\ m_{21}&m_{22}&m_{23}\end{pmatrix}\begin{pmatrix}j_{31}&j_{32}&j_{33}\\ m_{31}&m_{32}&m_{33}\end{pmatrix}\*\begin{pmatrix}j_{11}&j_{21}&j_{31}\\ m_{11}&m_{21}&m_{31}\end{pmatrix}\begin{pmatrix}j_{12}&j_{22}&j_{32}\\ m_{12}&m_{22}&m_{32}\end{pmatrix}$
Originally the third $\mathit{3j}$ symbol in the summation was written incorrectly as $\begin{pmatrix}j_{31}&j_{32}&j_{33}\\ m_{13}&m_{23}&m_{33}\end{pmatrix}.$
Reported 2015-01-19 by Yan-Rui Liu.
Other Changes
• To increase the regions of validity (5.9.10), (5.9.11), (5.10.1), (5.11.1), and (5.11.8), the logarithms of the gamma function that appears on their left-hand sides have all been changed to $\mathop{\mathrm{Ln}\/}\nolimits\mathop{\Gamma\/}\nolimits\!\left(\cdot\right)$, where $\mathop{\mathrm{Ln}\/}\nolimits$ is the general logarithm. Originally $\mathop{\ln\/}\nolimits\mathop{\Gamma\/}\nolimits\!\left(\cdot\right)$ was used, where $\mathop{\ln\/}\nolimits$ is the principal branch of the logarithm. These changes were recommended by Philippe Spindel on 2015-02-06.
• The notation used for the $q$-Appell functions in Section 17.1 and Equations (17.4.5), (17.4.6),(17.4.7), (17.4.8), (17.11.1), (17.11.2) and (17.11.3) was updated to explicitly include the argument $q$, as used in Gasper and Rahman (2004).
• A note was added after (22.20.5) to deal with cases when computation of $\mathop{\mathrm{dn}\/}\nolimits\left(x,k\right)$ becomes numerically unstable near $x=K$.
• The spelling of the name Delannoy was corrected in several places in §26.6. Previously it was mispelled as Dellanoy.
• For consistency of notation across all chapters, the notation for logarithm has been changed to $\mathop{\ln\/}\nolimits$ from $\mathrm{log}$ throughout Chapter 27.
## Version 1.0.9 (August 29, 2014)
Equation (9.6.26)
9.6.26 $\mathop{\mathrm{Bi}\/}\nolimits'\!\left(z\right)=\frac{3^{1/6}}{\mathop{\Gamma% \/}\nolimits\!\left(\tfrac{1}{3}\right)}{\mathrm{e}^{-\zeta}}\mathop{{{}_{1}F_% {1}}\/}\nolimits\!\left(-\tfrac{1}{6};-\tfrac{1}{3};2\zeta\right)+\frac{3^{7/6% }}{2^{7/3}\mathop{\Gamma\/}\nolimits\!\left(\tfrac{2}{3}\right)}\zeta^{4/3}{% \mathrm{e}^{-\zeta}}\mathop{{{}_{1}F_{1}}\/}\nolimits\!\left(\tfrac{7}{6};% \tfrac{7}{3};2\zeta\right)$
Originally the second occurrence of the function $\mathop{{{}_{1}F_{1}}\/}\nolimits$ was given incorrectly as $\mathop{{{}_{1}F_{1}}\/}\nolimits\!\left(\tfrac{7}{6};\tfrac{7}{3};\zeta\right)$.
Reported 2014-05-21 by Hanyou Chu.
Equation (22.19.6)
22.19.6 $x(t)=\mathop{\mathrm{cn}\/}\nolimits\left(t\sqrt{1+2\eta},k\right)$
Originally the term $\sqrt{1+2\eta}$ was given incorrectly as $\sqrt{1+\eta}$ in this equation and in the line above. Additionally, for improved clarity, the modulus $k=1/\sqrt{2+\eta^{-1}}$ has been defined in the line above.
Reported 2014-05-02 by Svante Janson.
Paragraph 22.19(ii)
Two corrections have been made in this paragraph. First, the correct range of the initial displacement $a$ is $\sqrt{1/\beta}\leq|a|<\sqrt{2/\beta}$. Previously it was $\sqrt{1/\beta}\leq|a|\leq\sqrt{2/\beta}$. Second, the correct period of the oscillations is $2\!\mathop{K\/}\nolimits\!\left(k\right)/\sqrt{\eta}$. Previously it was given incorrectly as $4\!\mathop{K\/}\nolimits\!\left(k\right)/\sqrt{\eta}$.
Reported 2014-05-02 by Svante Janson.
Equation (34.3.7)
34.3.7 $\begin{pmatrix}j_{1}&j_{2}&j_{3}\\ j_{1}&-j_{1}-m_{3}&m_{3}\end{pmatrix}=(-1)^{j_{1}-j_{2}-m_{3}}\left(\frac{(2j_% {1})!(-j_{1}+j_{2}+j_{3})!(j_{1}+j_{2}+m_{3})!(j_{3}-m_{3})!}{(j_{1}+j_{2}+j_{% 3}+1)!(j_{1}-j_{2}+j_{3})!(j_{1}+j_{2}-j_{3})!(-j_{1}+j_{2}-m_{3})!(j_{3}+m_{3% })!}\right)^{\frac{1}{2}}$
In the original equation the prefactor of the above 3j symbol read $(-1)^{-j_{2}+j_{3}+m_{3}}$. It is now replaced by its correct value $(-1)^{j_{1}-j_{2}-m_{3}}$.
Reported 2014-06-12 by James Zibin.
Other Changes
## Version 1.0.8 (April 25, 2014)
Equation (22.19.2)
22.19.2 $\mathop{\sin\/}\nolimits\!\left(\tfrac{1}{2}\theta(t)\right)=\mathop{\sin\/}% \nolimits\!\left(\frac{1}{2}\alpha\right)\mathop{\mathrm{sn}\/}\nolimits\left(% t+K,\mathop{\sin\/}\nolimits\!\left(\tfrac{1}{2}\alpha\right)\right)$
Originally the first argument to the function $\mathop{\mathrm{sn}\/}\nolimits$ was given incorrectly as $t$. The correct argument is $t+K$.
Reported 2014-03-05 by Svante Janson.
Equation (22.19.3)
22.19.3 $\theta(t)=2\mathop{\mathrm{am}\/}\nolimits\left(t\sqrt{E/2},\sqrt{2/E}\right)$
Originally the first argument to the function $\mathop{\mathrm{am}\/}\nolimits$ was given incorrectly as $t$. The correct argument is $t\,\sqrt{E/2}$.
Reported 2014-03-05 by Svante Janson.
Other Changes
• Equation (10.13.4) has been generalized to cover an additional case.
• We avoid the troublesome symbols, often missing in installed fonts, previously used for exponential $\mathrm{e}$, imaginary $\mathrm{i}$ and differential $\mathrm{d}$.
## Version 1.0.7 (March 21, 2014)
Table 3.5.19
The correct headings for the second and third columns of this table are $\mathop{J_{0}\/}\nolimits\!\left(t\right)$ and $g(t)$, respectively. Previously these columns were mislabeled as $g(t)$ and $\mathop{J_{0}\/}\nolimits\!\left(t\right)$.
Reported 2014-01-31 by Masataka Urago.
Table 3.5.21
The correct corner coordinates for the 9-point square, given on the last line of this table, are $(\pm\sqrt{\tfrac{3}{5}}h,\pm\sqrt{\tfrac{3}{5}}h)$. Originally they were given incorrectly as $(\pm\sqrt{\tfrac{3}{5}}h,0)$, $(\pm\sqrt{\tfrac{3}{5}}h,0)$.
Reported 2014-01-13 by Stanley Oleszczuk.
Equation (4.21.1)
4.21.1 $\mathop{\sin\/}\nolimits u\pm\mathop{\cos\/}\nolimits u=\sqrt{2}\mathop{\sin\/% }\nolimits\!\left(u\pm\tfrac{1}{4}\pi\right)=\pm\sqrt{2}\mathop{\cos\/}% \nolimits\!\left(u\mp\tfrac{1}{4}\pi\right)$
Originally the symbol $\pm$ was missing after the second equal sign.
Reported 2012-09-27 by Dennis Heim.
Equations (4.23.34) and (4.23.35)
4.23.34 $\mathop{\mathrm{arcsin}\/}\nolimits z=\mathop{\mathrm{arcsin}\/}\nolimits\beta% +\mathrm{i}\mathop{\mathrm{sign}\/}\nolimits\!\left(y\right)\mathop{\ln\/}% \nolimits\!\left(\alpha+(\alpha^{2}-1)^{1/2}\right)$
and
4.23.35 $\mathop{\mathrm{arccos}\/}\nolimits z=\mathop{\mathrm{arccos}\/}\nolimits\beta% -\mathrm{i}\mathop{\mathrm{sign}\/}\nolimits\!\left(y\right)\mathop{\ln\/}% \nolimits\!\left(\alpha+(\alpha^{2}-1)^{1/2}\right)$
Originally the factor $\mathop{\mathrm{sign}\/}\nolimits\!\left(y\right)$ was missing from the second term on the right sides of these equations. Additionally, the condition for the validity of these equations has been weakened.
Reported 2013-07-01 by Volker Thürey.
Equation (5.17.5)
5.17.5 $\mathop{\mathrm{Ln}\/}\nolimits\mathop{G\/}\nolimits\!\left(z+1\right)\sim% \tfrac{1}{4}z^{2}+z\mathop{\mathrm{Ln}\/}\nolimits\mathop{\Gamma\/}\nolimits\!% \left(z+1\right)-\left(\tfrac{1}{2}z(z+1)+\tfrac{1}{12}\right)\mathop{\mathrm{% Ln}\/}\nolimits z-\mathop{\ln\/}\nolimits A+\sum_{k=1}^{\infty}\frac{\mathop{B% _{2k+2}\/}\nolimits}{2k(2k+1)(2k+2)z^{2k}}$
Originally the term $z\mathop{\mathrm{Ln}\/}\nolimits\mathop{\Gamma\/}\nolimits\!\left(z+1\right)$ was incorrectly stated as $z\mathop{\Gamma\/}\nolimits\!\left(z+1\right)$.
Reported 2013-08-01 by Gergő Nemes and subsequently by Nick Jones on December 11, 2013.
Table 22.4.3
Originally a minus sign was missing in the entries for $\mathop{\mathrm{cd}\/}\nolimits u$ and $\mathop{\mathrm{dc}\/}\nolimits u$ in the second column (headed $z+K+iK^{\prime}$). The correct entries are $-k^{-1}\mathop{\mathrm{ns}\/}\nolimits z$ and $-k\mathop{\mathrm{sn}\/}\nolimits z$. Note: These entries appear online but not in the published print edition. More specifically, Table 22.4.3 in the published print edition is restricted to the three Jacobian elliptic functions $\mathop{\mathrm{sn}\/}\nolimits,\mathop{\mathrm{cn}\/}\nolimits,\mathop{% \mathrm{dn}\/}\nolimits$, whereas Table 22.4.3 covers all 12 Jacobian elliptic functions.
Reported 2014-02-28 by Svante Janson.
Table 22.5.2
The entry for $\mathop{\mathrm{sn}\/}\nolimits z$ at $z=\frac{3}{2}(K+\mathrm{i}K^{\prime})$ has been corrected. The correct entry is $(1+\mathrm{i})((1+k^{\prime})^{1/2}-\mathrm{i}(1-k^{\prime})^{1/2})/(2k^{1/2})$. Originally the terms $(1+k^{\prime})^{1/2}$ and $(1-k^{\prime})^{1/2}$ were given incorrectly as $(1+k)^{1/2}$ and $(1-k)^{1/2}$.
Similarly, the entry for $\mathop{\mathrm{dn}\/}\nolimits z$ at $z=\frac{3}{2}(K+\mathrm{i}K^{\prime})$ has been corrected. The correct entry is $(-1+\mathrm{i}){k^{\prime}}^{1/2}((1+k)^{1/2}+i(1-k)^{1/2})/2$. Originally the terms $(1+k)^{1/2}$ and $(1-k)^{1/2}$ were given incorrectly as $(1+k^{\prime})^{1/2}$ and $(1-k^{\prime})^{1/2}$
Reported 2014-02-28 by Svante Janson.
Equation (22.6.7)
22.6.7 $\mathop{\mathrm{dn}\/}\nolimits\left(2z,k\right)=\frac{{\mathop{\mathrm{dn}\/}% \nolimits^{2}}\left(z,k\right)-k^{2}{\mathop{\mathrm{sn}\/}\nolimits^{2}}\left% (z,k\right){\mathop{\mathrm{cn}\/}\nolimits^{2}}\left(z,k\right)}{1-k^{2}{% \mathop{\mathrm{sn}\/}\nolimits^{4}}\left(z,k\right)}=\frac{{\mathop{\mathrm{% dn}\/}\nolimits^{4}}\left(z,k\right)+k^{2}{k^{\prime}}^{2}{\mathop{\mathrm{sn}% \/}\nolimits^{4}}\left(z,k\right)}{1-k^{2}{\mathop{\mathrm{sn}\/}\nolimits^{4}% }\left(z,k\right)}$
Originally the term $k^{2}{\mathop{\mathrm{sn}\/}\nolimits^{2}}\left(z,k\right){\mathop{\mathrm{cn}% \/}\nolimits^{2}}\left(z,k\right)$ was given incorrectly as $k^{2}{\mathop{\mathrm{sn}\/}\nolimits^{2}}\left(z,k\right){\mathop{\mathrm{dn}% \/}\nolimits^{2}}\left(z,k\right)$.
Reported 2014-02-28 by Svante Janson.
Table 26.8.1
Originally the Stirling number $\mathop{s\/}\nolimits\!\left(10,6\right)$ was given incorrectly as 6327. The correct number is 63273.
Reported 2013-11-25 by Svante Janson.
Equation (31.8.5)
31.8.5 $\Psi_{1,-1}=\left(z^{2}+(\lambda+3a+3)z+a\right)/z^{3}$
Originally the first term on the right side of the equation for $\Psi_{1,-1}$ was $z^{3}$. The correct factor is $z^{2}$.
Reported 2013-07-25 by Christopher Künstler.
Equation (31.12.3)
31.12.3 $\frac{{\mathrm{d}}^{2}w}{{\mathrm{d}z}^{2}}-\left(\frac{\gamma}{z}+\delta+z% \right)\frac{\mathrm{d}w}{\mathrm{d}z}+\frac{\alpha z-q}{z}w=0$
Originally the sign in front of the second term in this equation was $+$. The correct sign is $-$.
Reported 2013-10-31 by Henryk Witek.
Equation (34.4.2)
34.4.2 $\begin{Bmatrix}j_{1}&j_{2}&j_{3}\\ l_{1}&l_{2}&l_{3}\end{Bmatrix}=\Delta(j_{1}j_{2}j_{3})\Delta(j_{1}l_{2}l_{3})% \Delta(l_{1}j_{2}l_{3})\Delta(l_{1}l_{2}j_{3})\*\sum_{s}\frac{(-1)^{s}(s+1)!}{% (s-j_{1}-j_{2}-j_{3})!(s-j_{1}-l_{2}-l_{3})!(s-l_{1}-j_{2}-l_{3})!(s-l_{1}-l_{% 2}-j_{3})!}\*\frac{1}{(j_{1}+j_{2}+l_{1}+l_{2}-s)!(j_{2}+j_{3}+l_{2}+l_{3}-s)!% (j_{3}+j_{1}+l_{3}+l_{1}-s)!}$
Originally the factor $\Delta(j_{1}j_{2}j_{3})\Delta(j_{1}l_{2}l_{3})\Delta(l_{1}j_{2}l_{3})\Delta(l_% {1}l_{2}j_{3})$ was missing in this equation.
Reported 2012-12-31 by Yu Lin.
Other Changes
• Equations (4.45.8) and (4.45.9) have been replaced with equations that are better for numerically computing $\mathop{\mathrm{arctan}\/}\nolimits x$.
• A new subsection 13.29(v) has been added to cover computation of confluent hypergeometric functions by continued fractions.
• A new subsection 14.5(vi) containing the values of Legendre and Ferrers functions for degree $\nu=2$ has been added.
• Subsection 14.18(iii) has been altered to identify Equations (14.18.6) and (14.18.7) as Christoffel’s Formulas.
• A new subsection 15.19(v) has been added to cover computation of the Gauss hypergeometric functions by continued fractions.
• Special cases of normalization of Jacobi polynomials for which the general formula is undefined have been stated explicitly in Table 18.3.1.
• Cross-references have been added in §§1.2(i), 10.19(iii), 10.23(ii), 17.2(iii), 18.15(iii), 19.2(iv), 19.16(i).
• Several small revisions have been made. For details see §§5.11(ii), 10.12, 10.19(ii), 18.9(i), 18.16(iv), 19.7(ii), 22.2, 32.11(v), 32.13(ii).
• Entries for the Sage computational system have been updated in the Software Index.
• The default document format for DLMF is now HTML5 which includes MathML providing better accessibility and display of mathematics.
• All interactive 3D graphics on the DLMF website have been recast using WebGL and X3DOM, improving portability and performance; WebGL it is now the default format.
## Version 1.0.6 (May 6, 2013)
Several minor improvements were made affecting display and layout; primarily tracking changes to the underlying LaTeXML system.
## Version 1.0.5 (October 1, 2012)
Subsection 1.2(i)
The condition for (1.2.2), (1.2.4), and (1.2.5) was corrected. These equations are true only if $n$ is a positive integer. Previously $n$ was allowed to be zero.
Reported 2011-08-10 by Michael Somos.
Subsection 8.17(i)
The condition for the validity of (8.17.5) is that $m$ and $n$ are positive integers and $0\leq x<1$. Previously, no conditions were stated.
Reported 2011-03-23 by Stephen Bourn.
Equation (10.20.14)
10.20.14 $B_{3}(0)=-\tfrac{959\;71711\;84603}{25\;47666\;37125\;00000}2^{\frac{1}{3}}$
Originally this coefficient was given incorrectly as $B_{3}(0)=-\tfrac{430\;99056\;39368\;59253}{5\;68167\;34399\;42500\;00000}2^{% \frac{1}{3}}$. The other coefficients in this equation have not been changed.
Reported 2012-05-11 by Antony Lee.
Equation (13.16.4)
The condition for the validity of this equation is $\Re{(\kappa-\mu)-\tfrac{1}{2}}<0$. Originally it was given incorrectly as $\Re{(\kappa-\mu)-\tfrac{1}{2}}>0$.
Subsection 14.2(ii)
Originally it was stated, incorrectly, that $\mathop{Q^{\mu}_{\nu}\/}\nolimits\!\left(x\right)$ is real when $\nu,\mu\in\mathbb{R}$ and $x\in(1,\infty)$. This statement is true only for $\mathop{P^{\mu}_{\nu}\/}\nolimits\!\left(x\right)$ and $\mathop{\boldsymbol{Q}^{\mu}_{\nu}\/}\nolimits\!\left(x\right)$.
Reported 2012-07-18 by Hans Volkmer and Howard Cohl.
Equation (21.3.4)
21.3.4 $\mathop{\theta\!\genfrac{[}{]}{0.0pt}{}{\boldsymbol{{\alpha}}+\mathbf{m}_{1}}{% \boldsymbol{{\beta}}+\mathbf{m}_{2}}\/}\nolimits\!\left(\mathbf{z}\middle|% \boldsymbol{{\Omega}}\right)={\mathrm{e}^{2\pi\mathrm{i}\boldsymbol{{\alpha}}% \cdot\mathbf{m}_{2}}}\mathop{\theta\!\genfrac{[}{]}{0.0pt}{}{\boldsymbol{{% \alpha}}}{\boldsymbol{{\beta}}}\/}\nolimits\!\left(\mathbf{z}\middle|% \boldsymbol{{\Omega}}\right)$
Originally the vector $\mathbf{m}_{2}$ on the right-hand side was given incorrectly as $\mathbf{m}_{1}$.
Reported 2012-08-27 by Klaas Vantournhout.
Subsection 21.10(i)
The entire original content of this subsection has been replaced by a reference.
Figures 22.3.22 and 22.3.23
The captions for these figures have been corrected to read, in part, “as a function of $k^{2}=\mathrm{i}\kappa^{2}$” (instead of $k^{2}=\mathrm{i}\kappa$). Also, the resolution of the graph in Figure 22.3.22 was improved near $\kappa=3$.
Reported 2011-10-30 by Paul Abbott.
Equation (23.2.4)
23.2.4 $\mathop{\wp\/}\nolimits\!\left(z\right)=\frac{1}{z^{2}}+\sum_{w\in\mathbb{L}% \setminus\{0\}}\left(\frac{1}{(z-w)^{2}}-\frac{1}{w^{2}}\right)$
Originally the denominator $(z-w)^{2}$ was given incorrectly as $(z-w^{2})$.
Reported 2012-02-16 by James D. Walker.
Equation (24.4.26)
This equation is true only for $n>0$. Previously, $n=0$ was also allowed.
Equation (26.12.26)
26.12.26 $\mathop{\mathrm{pp}\/}\nolimits\!\left(n\right)\sim\frac{\left(\mathop{\zeta\/% }\nolimits\!\left(3\right)\right)^{7/36}}{2^{11/36}(3\pi)^{1/2}n^{25/36}}% \mathop{\exp\/}\nolimits\!\left(3\left(\mathop{\zeta\/}\nolimits\!\left(3% \right)\right)^{1/3}\left(\tfrac{1}{2}n\right)^{2/3}+\mathop{\zeta\/}\nolimits% '\!\left(-1\right)\right).$
Originally this equation was given incorrectly as
$\mathop{\mathrm{pp}\/}\nolimits\!\left(n\right)\sim\left(\frac{\mathop{\zeta\/% }\nolimits\!\left(3\right)}{2^{11}n^{25}}\right)^{1/36}\*\mathop{\exp\/}% \nolimits\!\left(3\left(\frac{\mathop{\zeta\/}\nolimits\!\left(3\right)n^{2}}{% 4}\right)^{1/3}+\mathop{\zeta\/}\nolimits'\!\left(-1\right)\right).$
Reported 2011-09-05 by Suresh Govindarajan.
Other Changes
## Version 1.0.4 (March 23, 2012)
Several minor improvements were made affecting display of math and graphics on the web site; the software index and help files were updated.
## Version 1.0.3 (Aug 29, 2011)
Equation (13.18.7)
13.18.7 $\mathop{W_{-\frac{1}{4},\pm\frac{1}{4}}\/}\nolimits\!\left(z^{2}\right)={% \mathrm{e}^{\frac{1}{2}z^{2}}}\sqrt{\pi z}\mathop{\mathrm{erfc}\/}\nolimits\!% \left(z\right)$
Originally the left-hand side was given correctly as $\mathop{W_{-\frac{1}{4},-\frac{1}{4}}\/}\nolimits\!\left(z^{2}\right)$; the equation is true also for $\mathop{W_{-\frac{1}{4},+\frac{1}{4}}\/}\nolimits\!\left(z^{2}\right)$.
Other Changes
Bibliographic citations were added in §§3.5(iv), 4.44, 8.22(ii), 22.4(i), and minor clarifications were made in §§19.12, 20.7(vii), 22.9(i). In addition, several minor improvements were made affecting only ancilliary documents and links in the online version.
## Version 1.0.2 (July 1, 2011)
Several minor improvements were made affecting display on the web site; the help files were revised.
## Version 1.0.1 (June 27, 2011)
Subsections 1.15(vi) and 1.15(vii)
The formulas in these subsections are valid only for $x\geq 0$. No conditions on $x$ were given originally.
Reported 2010-10-18 by Andreas Kurt Richter.
Figure 10.48.5
Originally the ordinate labels 2 and 4 in this figure were placed too high.
Reported 2010-11-08 by Wolfgang Ehrhardt.
Equation (14.19.2)
14.19.2 $\mathop{P^{\mu}_{\nu-\frac{1}{2}}\/}\nolimits\!\left(\mathop{\cosh\/}\nolimits% \xi\right)=\frac{\mathop{\Gamma\/}\nolimits\!\left(\frac{1}{2}-\mu\right)}{{% \pi^{1/2}}\left(1-{\mathrm{e}^{-2\xi}}\right)^{\mu}{\mathrm{e}^{(\nu+(1/2))\xi% }}}\*\mathop{\mathbf{F}\/}\nolimits\!\left(\tfrac{1}{2}-\mu,\tfrac{1}{2}+\nu-% \mu;1-2\mu;1-{\mathrm{e}^{-2\xi}}\right),$ $\mu\neq\frac{1}{2},\frac{3}{2},\frac{5}{2},\ldots$.
Originally the argument to $\mathop{\mathbf{F}\/}\nolimits$ in this equation was incorrect (${\mathrm{e}^{-2\xi}}$, rather than $1-{\mathrm{e}^{-2\xi}}$), and the condition on $\mu$ was too weak ($\mu\neq\frac{1}{2}$, rather than $\mu\neq\frac{1}{2},\frac{3}{2},\frac{5}{2},\ldots$). Also, the factor multiplying $\mathop{\mathbf{F}\/}\nolimits$ was rewritten to clarify the poles; originally it was $\frac{\mathop{\Gamma\/}\nolimits\!\left(1-2\mu\right)2^{2\mu}}{\mathop{\Gamma% \/}\nolimits\!\left(1-\mu\right)\left(1-{\mathrm{e}^{-2\xi}}\right)^{\mu}{% \mathrm{e}^{(\nu+(1/2))\xi}}}$.
Reported 2010-11-02 by Alvaro Valenzuela.
Equation (17.13.3)
17.13.3 $\int_{0}^{\infty}t^{\alpha-1}\frac{\left(-tq^{\alpha+\beta};q\right)_{\infty}}% {\left(-t;q\right)_{\infty}}\mathrm{d}t=\frac{\mathop{\Gamma\/}\nolimits\!% \left(\alpha\right)\mathop{\Gamma\/}\nolimits\!\left(1-\alpha\right)\mathop{% \Gamma_{q}\/}\nolimits\!\left(\beta\right)}{\mathop{\Gamma_{q}\/}\nolimits\!% \left(1-\alpha\right)\mathop{\Gamma_{q}\/}\nolimits\!\left(\alpha+\beta\right)},$
Originally the differential was identified incorrectly as ${\mathrm{d}}_{q}t$; the correct differential is $\mathrm{d}t$.
Reported 2011-04-08.
Table 18.9.1
The coefficient $A_{n}$ for $\mathop{C^{(\lambda)}_{n}\/}\nolimits\!\left(x\right)$ in the first row of this table originally omitted the parentheses and was given as $\frac{2n+\lambda}{n+1}$, instead of $\frac{2(n+\lambda)}{n+1}$.
Reported 2010-09-16 by Kendall Atkinson.
Subsection 19.16(iii)
Originally it was implied that $\mathop{R_{C}\/}\nolimits\!\left(x,y\right)$ is an elliptic integral. It was clarified that $\mathop{R_{-a}\/}\nolimits\!\left(\mathbf{b};\mathbf{z}\right)$ is an elliptic integral iff the stated conditions hold; originally these conditions were stated as sufficient but not necessary. In particular, $\mathop{R_{C}\/}\nolimits\!\left(x,y\right)$ does not satisfy these conditions.
Reported 2010-11-23.
Table 22.5.4
Originally the limiting form for $\mathop{\mathrm{sc}\/}\nolimits\left(z,k\right)$ in the last line of this table was incorrect ($\mathop{\cosh\/}\nolimits z$, instead of $\mathop{\sinh\/}\nolimits z$).
Reported 2010-11-23.
Equation (22.16.14)
22.16.14 $\mathop{\mathcal{E}\/}\nolimits\!\left(x,k\right)=\int_{0}^{\mathop{\mathrm{sn% }\/}\nolimits\left(x,k\right)}\sqrt{\frac{1-k^{2}t^{2}}{1-t^{2}}}\mathrm{d}t$
Originally this equation appeared with the upper limit of integration as $x$, rather than $\mathop{\mathrm{sn}\/}\nolimits\left(x,k\right)$.
Reported 2010-07-08 by Charles Karney.
Equation (26.7.6)
26.7.6 $\mathop{B\/}\nolimits\!\left(n+1\right)=\sum_{k=0}^{n}\binom{n}{k}\mathop{B\/}% \nolimits\!\left(k\right)$
Originally this equation appeared with $\mathop{B\/}\nolimits\!\left(n\right)$ in the summation, instead of $\mathop{B\/}\nolimits\!\left(k\right)$.
Reported 2010-11-07 by Layne Watson.
Equation (36.10.14)
36.10.14 $3\left(\frac{{\partial}^{2}\mathop{\Psi^{(\mathrm{E})}\/}\nolimits}{{\partial x% }^{2}}-\frac{{\partial}^{2}\mathop{\Psi^{(\mathrm{E})}\/}\nolimits}{{\partial y% }^{2}}\right)+2\mathrm{i}z\frac{\partial\mathop{\Psi^{(\mathrm{E})}\/}% \nolimits}{\partial x}-x\mathop{\Psi^{(\mathrm{E})}\/}\nolimits=0$
Originally this equation appeared with $\frac{\partial\mathop{\Psi^{(\mathrm{H})}\/}\nolimits}{\partial x}$ in the second term, rather than $\frac{\partial\mathop{\Psi^{(\mathrm{E})}\/}\nolimits}{\partial x}$.
Reported 2010-04-02.
Other Changes
• The definition of the notation $F(z_{0}{\mathrm{e}^{2k\pi\mathrm{i}}})$ was added in Common Notations and Definitions.
• Clarifications were made in §§5.18, 7.1,
• Bibliographic citations were added in §§1.13(v), 10.14, 10.21(ii), 18.15(v), 18.32, 30.16(iii), 32.13(ii), and as general references in Chapters 19, 20, 22, and 23.
• The general references for each chapter were inserted under the i-symbol on the chapter title pages. Originally these appeared only in the References sections of the individual chapters in the Handbook.
• The definition of $\mathop{R_{C}\/}\nolimits\!\left(x,y\right)$ was revised in Notations.
• Additions and revisions were made in the Cross Index for Computing Special Functions
## Version 1.0.0 (May 7, 2010)
The Handbook of Mathematical Functions was published, and the Digital Library of Mathematical Functions was released.
| 2017-01-24T09:10:58 |
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|
https://par.nsf.gov/biblio/10303690-elemental-abundances-m31-properties-inner-stellar-halo
|
Elemental Abundances in M31: Properties of the Inner Stellar Halo*
Abstract
We present measurements of [Fe/H] and [α/Fe] for 128 individual red giant branch stars (RGB) in the stellar halo of M31, including its Giant Stellar Stream (GSS), obtained using spectral synthesis of low- and medium-resolution Keck/DEIMOS spectroscopy (and 6000, respectively). We observed four fields in M31's stellar halo (at projected radii of 9, 18, 23, and 31 kpc), as well as two fields in the GSS (at 33 kpc). In combination with existing literature measurements, we have increased the sample size of [Fe/H] and [α/Fe] measurements from 101 to a total of 229 individual M31 RGB stars. From this sample, we investigate the chemical abundance properties of M31's inner halo, findingand. Between 8 and 34 kpc, the inner halo has a steep [Fe/H] gradient (−0.025 ± 0.002 dex kpc−1) and negligible [α/Fe] gradient, where substructure in the inner halo is systematically more metal-rich than the smooth component of the halo at a given projected distance. Although the chemical abundances of the inner stellar halo are largely inconsistent with that of present-day dwarf spheroidal (dSph) satellite galaxies of M31, we identified 22 RGB stars kinematically associated with the smooth component of the stellar halo more »
Authors:
; ; ; ; ;
Publication Date:
NSF-PAR ID:
10303690
Journal Name:
The Astrophysical Journal
Volume:
902
Issue:
1
Page Range or eLocation-ID:
Article No. 51
ISSN:
0004-637X
Publisher:
DOI PREFIX: 10.3847
National Science Foundation
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We use deep narrowband CaHK (F395N) imaging taken with the Hubble Space Telescope (HST) to construct the metallicity distribution function (MDF) of Local Group ultra-faint dwarf galaxy EridanusII(EriII). When combined with archival F475W and F814W data, we measure metallicities for 60 resolved red giant branch stars as faint asmF475W∼ 24 mag, a factor of ∼4× more stars than current spectroscopic MDF determinations. We find that EriIIhas a mean metallicity of [Fe/H] = −2.50$−0.07+0.07$and a dispersion of$σ[Fe/H]=0.42−0.06+0.06$, which are consistent with spectroscopic MDFs, though more precisely constrained owing to a larger sample. We identify a handful of extremely metal-poor star candidates (EMP; [Fe/H] < −3) that are marginally bright enough for spectroscopic follow-up. The MDF of EriIIappears well described by a leaky box chemical evolution model. We also compute an updated orbital history for EriIIusing Gaia eDR3 proper motions, and find that it is likely on first infall into the Milky Way. Our findings suggest that EriIIunderwent an evolutionary history similar to that of an isolated galaxy. Compared to MDFs for select cosmological simulations of similar mass galaxies, we find that EriIIhas a lower fraction of stars withmore »
| 2022-12-08T18:41:15 |
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|
http://legisquebec.gouv.qc.ca/en/showversion/cs/O-9?code=se:137&pointInTime=20201022
|
### O-9 - Act respecting municipal territorial organization
137. Where the area to be annexed is situated within the territory of more than one local municipality, the procedure provided for in sections 133 and 134 shall apply to each municipality.
The qualified voters of the area to be annexed are, for the purposes of the first paragraph, the qualified voters of that part of the area to be annexed which is situated within the territory of each of such municipalities.
1988, c. 19, s. 137; 1993, c. 65, s. 41.
137. Where the area to be annexed is situated within the territory of more than one local municipality, the procedure provided for in sections 133 and 134 shall apply to each municipality.
The qualified voters and interested persons of the area to be annexed are, for the purposes of the first paragraph, the qualified voters and interested persons of that part of the area to be annexed which is situated within the territory of each of such municipalities.
1988, c. 19, s. 137.
| 2021-04-23T08:37:02 |
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|
https://par.nsf.gov/biblio/10353248-late-time-evolution-modeling-off-axis-gamma-ray-burst-candidate-first-j141918
|
This content will become publicly available on January 1, 2023
Late-time Evolution and Modeling of the Off-axis Gamma-Ray Burst Candidate FIRST J141918.9+394036
Abstract We present new radio and optical data, including very-long-baseline interferometry, as well as archival data analysis, for the luminous, decades-long radio transient FIRST J141918.9+394036. The radio data reveal a synchrotron self-absorption peak around 0.3 GHz and a radius of around 1.3 mas (0.5 pc) 26 yr post-discovery, indicating a blastwave energy ∼5 × 10 50 erg. The optical spectrum shows a broad [O iii ] λ 4959,5007 emission line that may indicate collisional excitation in the host galaxy, but its association with the transient cannot be ruled out. The properties of the host galaxy are suggestive of a massive stellar progenitor that formed at low metallicity. Based on the radio light curve, blastwave velocity, energetics, nature of the host galaxy and transient rates, we find that the properties of J1419+3940 are most consistent with long gamma-ray burst (LGRB) afterglows. Other classes of (optically discovered) stellar explosions as well as neutron star mergers are disfavored, and invoking any exotic scenario may not be necessary. It is therefore likely that J1419+3940 is an off-axis LGRB afterglow (as suggested by Law et al. and Marcote et al.), and under this premise the inverse beaming fraction is found to be f b − more »
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ;
Award ID(s):
Publication Date:
NSF-PAR ID:
10353248
Journal Name:
The Astrophysical Journal
Volume:
924
Issue:
1
Page Range or eLocation-ID:
16
ISSN:
0004-637X
2. ABSTRACT Numerous studies of integrated starlight, stellar counts, and kinematics have confirmed that the Milky Way is a barred galaxy. However, far fewer studies have investigated the bar’s stellar population properties, which carry valuable independent information regarding the bar’s formation history. Here, we conduct a detailed analysis of chemical abundance distributions ([Fe/H] and [Mg/Fe]) in the on-bar and off-bar regions to study the azimuthal variation of star formation history (SFH) in the inner Galaxy. We find that the on-bar and off-bar stars at Galactocentric radii 3 kpc < rGC < 5 kpc have remarkably consistent [Fe/H] and [Mg/Fe] distribution functions and [Mg/Fe]–[Fe/H] relation, suggesting a common SFH shared by the long bar and the disc. In contrast, the bar and disc at smaller radii (2 kpc < rGC < 3 kpc) show noticeable differences, with relatively more very metal-rich ($\rm [Fe/H] \sim 0.4$) stars but fewer solar abundance stars in the bar. Given the three-phase star formation history proposed for the inner Galaxy in Lian et al., these differences could be explained by the off-bar disc having experienced either a faster early quenching process or recent metal-poor gas accretion. Vertical variations of the abundance distributions at small rGC suggest a wider vertical distribution of low-αmore »
| 2022-12-07T04:04:39 |
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|
https://www.itl.nist.gov/div898/handbook/eda/section3/eda352.htm
|
1. Exploratory Data Analysis
1.3. EDA Techniques
1.3.5. Quantitative Techniques
## Confidence Limits for the Mean
Purpose:
Interval Estimate for Mean
Confidence limits for the mean (Snedecor and Cochran, 1989) are an interval estimate for the mean. Interval estimates are often desirable because the estimate of the mean varies from sample to sample. Instead of a single estimate for the mean, a confidence interval generates a lower and upper limit for the mean. The interval estimate gives an indication of how much uncertainty there is in our estimate of the true mean. The narrower the interval, the more precise is our estimate.
Confidence limits are expressed in terms of a confidence coefficient. Although the choice of confidence coefficient is somewhat arbitrary, in practice 90 %, 95 %, and 99 % intervals are often used, with 95 % being the most commonly used.
As a technical note, a 95 % confidence interval does not mean that there is a 95 % probability that the interval contains the true mean. The interval computed from a given sample either contains the true mean or it does not. Instead, the level of confidence is associated with the method of calculating the interval. The confidence coefficient is simply the proportion of samples of a given size that may be expected to contain the true mean. That is, for a 95 % confidence interval, if many samples are collected and the confidence interval computed, in the long run about 95 % of these intervals would contain the true mean.
Definition: Confidence Interval Confidence limits are defined as:
$\bar{Y} \pm t_{1 - \alpha/2, \, N-1} \,\, \frac{s}{\sqrt{N}}$
where $$\bar{Y}$$ is the sample mean, s is the sample standard deviation, N is the sample size, α is the desired significance level, and t1-α/2, N-1 is the 100(1-α/2) percentile of the t distribution with N - 1 degrees of freedom. Note that the confidence coefficient is 1 - α.
From the formula, it is clear that the width of the interval is controlled by two factors:
1. As N increases, the interval gets narrower from the $$\sqrt{N}$$ term.
That is, one way to obtain more precise estimates for the mean is to increase the sample size.
2. The larger the sample standard deviation, the larger the confidence interval. This simply means that noisy data, i.e., data with a large standard deviation, are going to generate wider intervals than data with a smaller standard deviation.
Definition: Hypothesis Test To test whether the population mean has a specific value, $$\mu_{0}$$, against the two-sided alternative that it does not have a value $$\mu_{0}$$, the confidence interval is converted to hypothesis-test form. The test is a one-sample t-test, and it is defined as:
H0: $$\mu = \mu_{0}$$ Ha: $$\mu \neq \mu_{0}$$ Test Statistic: $$T = (\bar{Y} - \mu_{0})/(s/\sqrt{N})$$ where $$\bar{Y}$$, N, and s are defined as above. Significance Level: α. The most commonly used value for α is 0.05. Critical Region: Reject the null hypothesis that the mean is a specified value, $$\mu_{0}$$, if $$T < t_{\alpha/2, \, N-1}$$ or $$T > t_{1 - \alpha/2, \, N-1}$$
Confidence Interval Example We generated a 95 %, two-sided confidence interval for the ZARR13.DAT data set based on the following information.
N = 195
MEAN = 9.261460
STANDARD DEVIATION = 0.022789
t1-0.025,N-1 = 1.9723
LOWER LIMIT = 9.261460 - 1.9723*0.022789/√195
UPPER LIMIT = 9.261460 + 1.9723*0.022789/√195
Thus, a 95 % confidence interval for the mean is (9.258242, 9.264679).
t-Test Example We performed a two-sided, one-sample t-test using the ZARR13.DAT data set to test the null hypothesis that the population mean is equal to 5.
H0: μ = 5
Ha: μ ≠ 5
Test statistic: T = 2611.284
Degrees of freedom: ν = 194
Significance level: α = 0.05
Critical value: t1-α/2,ν = 1.9723
Critical region: Reject H0 if |T| > 1.9723
We reject the null hypotheses for our two-tailed t-test because the absolute value of the test statistic is greater than the critical value. If we were to perform an upper, one-tailed test, the critical value would be t1-α,ν = 1.6527, and we would still reject the null hypothesis.
The confidence interval provides an alternative to the hypothesis test. If the confidence interval contains 5, then H0 cannot be rejected. In our example, the confidence interval (9.258242, 9.264679) does not contain 5, indicating that the population mean does not equal 5 at the 0.05 level of significance.
In general, there are three possible alternative hypotheses and rejection regions for the one-sample t-test:
Alternative Hypothesis Rejection Region
Ha: μ ≠ μ0 |T| > t1-α/2,ν
Ha: μ > μ0 T > t1-α,ν
Ha: μ < μ0 T < tα,ν
The rejection regions for three posssible alternative hypotheses using our example data are shown in the following graphs.
Questions Confidence limits for the mean can be used to answer the following questions:
1. What is a reasonable estimate for the mean?
2. How much variability is there in the estimate of the mean?
3. Does a given target value fall within the confidence limits?
Related Techniques Two-Sample t-Test
Confidence intervals for other location estimators such as the median or mid-mean tend to be mathematically difficult or intractable. For these cases, confidence intervals can be obtained using the bootstrap.
Case Study Heat flow meter data.
Software Confidence limits for the mean and one-sample t-tests are available in just about all general purpose statistical software programs. Both Dataplot code and R code can be used to generate the analyses in this section. These scripts use the ZARR13.DAT data file.
| 2018-10-19T17:50:07 |
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|
https://www.scstatehouse.gov/sess122_2017-2018/bills/3386.htm
|
South Carolina General Assembly
122nd Session, 2017-2018
Indicates Matter Stricken
Indicates New Matter
H. 3386
STATUS INFORMATION
House Resolution
Document Path: l:\council\bills\rm\1057wab17.docx
Introduced in the House on January 11, 2017
Adopted by the House on January 11, 2017
Summary: Pickens High School March Band
HISTORY OF LEGISLATIVE ACTIONS
Date Body Action Description with journal page number
-------------------------------------------------------------------------------
1/11/2017 House Introduced and adopted (House Journal-page 20)
View the latest legislative information at the website
VERSIONS OF THIS BILL
(Text matches printed bills. Document has been reformatted to meet World Wide Web specifications.)
A HOUSE RESOLUTION
TO EXTEND THE PRIVILEGE OF THE FLOOR OF THE SOUTH CAROLINA HOUSE OF REPRESENTATIVES TO THE PICKENS HIGH SCHOOL MARCHING BAND, BAND DIRECTORS, AND SCHOOL OFFICIALS, AT A DATE AND TIME TO BE DETERMINED BY THE SPEAKER, FOR THE PURPOSE OF BEING RECOGNIZED AND COMMENDED FOR WINNING THE 2016 SOUTH CAROLINA BAND DIRECTORS ASSOCIATION CLASS AAA STATE CHAMPIONSHIP TITLE.
Be it resolved by the House of Representatives:
That the privilege of the floor of the South Carolina House of Representatives be extended to the Pickens High School marching band, band directors, and school officials, at a date and time to be determined by the Speaker, for the purpose of being recognized and commended for winning the 2016 South Carolina Band Directors Association Class AAA State Championship title.
----XX----
This web page was last updated on January 17, 2017 at 10:30 AM
| 2023-03-27T17:17:54 |
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|
https://lammps.sandia.gov/doc/fix_reax_bonds.html
|
# fix reax/c/bonds/kk command
## Syntax
fix ID group-ID reax/bonds Nevery filename
• ID, group-ID are documented in fix command
• reax/bonds = style name of this fix command
• Nevery = output interval in timesteps
• filename = name of output file
## Examples
fix 1 all reax/bonds 100 bonds.tatb
fix 1 all reax/c/bonds 100 bonds.reaxc
## Description
Write out the bond information computed by the ReaxFF potential specified by pair_style reax or pair_style reax/c in the exact same format as the original stand-alone ReaxFF code of Adri van Duin. The bond information is written to filename on timesteps that are multiples of Nevery, including timestep 0. For time-averaged chemical species analysis, please see the fix reaxc/c/species command.
The specified group-ID is ignored by this fix.
The format of the output file should be reasonably self-explanatory. The meaning of the column header abbreviations is as follows:
• id = atom id
• type = atom type
• nb = number of bonds
• id_1 = atom id of first bond
• id_nb = atom id of Nth bond
• mol = molecule id
• bo_1 = bond order of first bond
• bo_nb = bond order of Nth bond
• abo = atom bond order (sum of all bonds)
• nlp = number of lone pairs
• q = atomic charge
If the filename ends with “.gz”, the output file is written in gzipped format. A gzipped dump file will be about 3x smaller than the text version, but will also take longer to write.
Restart, fix_modify, output, run start/stop, minimize info:
No information about this fix is written to binary restart files. None of the fix_modify options are relevant to this fix. No global or per-atom quantities are stored by this fix for access by various output commands. No parameter of this fix can be used with the start/stop keywords of the run command. This fix is not invoked during energy minimization.
Styles with a gpu, intel, kk, omp, or opt suffix are functionally the same as the corresponding style without the suffix. They have been optimized to run faster, depending on your available hardware, as discussed in Speed of the manual. The accelerated styles take the same arguments and should produce the same results, except for round-off and precision issues.
These accelerated styles are part of the GPU, USER-INTEL, KOKKOS, USER-OMP and OPT packages, respectively. They are only enabled if LAMMPS was built with those packages. See the Build package doc page for more info.
You can specify the accelerated styles explicitly in your input script by including their suffix, or you can use the -suffix command-line switch when you invoke LAMMPS, or you can use the suffix command in your input script.
See Speed of the manual for more instructions on how to use the accelerated styles effectively.
## Restrictions
The fix reax/bonds command requires that the pair_style reax be invoked. This fix is part of the REAX package. It is only enabled if LAMMPS was built with that package, which also requires the REAX library be built and linked with LAMMPS. The fix reax/c/bonds command requires that the pair_style reax/c be invoked. This fix is part of the USER-REAXC package. It is only enabled if LAMMPS was built with that package. See the Build package doc page for more info.
To write gzipped bond files, you must compile LAMMPS with the -DLAMMPS_GZIP option.
| 2018-12-15T10:14:38 |
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|
http://www.hhs.gov/dab/decisions/dab1582.html
|
# Thereza Imanishi-Kari, Ph.D., DAB No. 1582 (1996)
Department of Health and Human Services
Departmental Appeals Board
RESEARCH INTEGRITY ADJUDICATIONS PANEL
SUBJECT: Thereza Imanishi-Kari, Ph.D.
Docket No. A-95-33
Decision No. 1582
DATE: June 21, 1996
DECISION
The Research Integrity Adjudications Panel appointed to hear the appeal of
Thereza Imanishi-Kari, Ph.D., from findings of scientific misconduct
concludes that the Office of Research Integrity (ORI) did not prove its
charges by a preponderance of the evidence. The Panel recommends that no
debarment be imposed and determines that no other administrative actions
should be taken.
ORI's charges relate to a paper co-authored by Dr. Imanishi-Kari
and published in the journal Cell in 1986. ORI found that Dr.
Imanishi-Kari had intentionally and deliberately fabricated and
falsified experimental data and results. Based on a report
issued by ORI, ORI and the Debarring Official for the Department
of Health and Human Services jointly proposed various
administrative actions, including a ten-year debarment from
receiving federal grant and contract awards.
The Panel included two members of the Departmental Appeals Board,
Judith A. Ballard and Cecilia Sparks Ford (who presided), and an
independent scientist, Dr. Julius S. Youngner, Distinguished
Service Professor Emeritus at the University of Pittsburgh School
of Medicine.
Dr. Imanishi-Kari's appeal presented complex and interrelated
arguments in a dispute which has a long and tangled history.
The Panel held a six-week hearing beginning in June 1995. We
amassed voluminous exhibits, including more than 70 original
laboratory notebooks, and a 6500-page hearing transcript. The
parties submitted lengthy factual and legal arguments, and ORI
proposed thousands of findings of fact and conclusions of law.
The record was completed in April 1996.
The Panel examined piece-by-piece all the record evidence,
including the original laboratory notebooks, as to each charge.
The Panel weighed testimony from numerous experts, not by
evaluating their credentials--all of which were impressive--but
by determining the basis for each opinion, any underlying
assumptions, and the probative value. The Panel also evaluated
the credibility of witnesses with firsthand knowledge of relevant
events, after observing their demeanor and comparing their
testimony to other evidence.
ORI presented forensic evidence using statistical and document
examination analyses. These analyses were based on unsupported
assumptions and, at best, inconclusive. To determine what
inferences to draw from the evidence, the Panel considered the
parties' arguments about all of the evidence and evaluated
relevant factors (such as possible motive).
Our decision is organized as follows. First, we set out the
legal framework for our decision and the undisputed facts about
the history of the case. We then summarize a number of general
findings made after analyzing the evidence on all of the charges;
these findings are reflected, but not necessarily repeated,
throughout our analyses of individual charges. The general
reader may find these first three sections a useful overview of
the case. We next discuss general conclusions on the statistical
and document examination analyses, and why they are of limited
probative value. Finally, we address in detail the evidence and
arguments on each individual charge.
I. LEGAL FRAMEWORK
The Department of Health and Human Services has the authority to
protect the integrity of research it funds by taking
administrative actions against those who have engaged in
scientific misconduct. In accordance with the guidelines for
these cases, Dr. Imanishi-Kari requested an evidentiary hearing
in response to the joint notice (Charge letter).
The Departmental Appeals Board (DAB), in the Office of the
Secretary, hears appeals from findings of scientific misconduct
made by ORI, whether or not debarment is one of the actions
proposed. 1/ See 57 Fed. Reg. 53,125 (1992); 59 Fed. Reg. 29,809
(1994). Under the guidelines, a Research Integrity Adjudications
Panel is appointed to decide each appeal. For this case, after
consulting with the parties, the Board Chair appointed Dr.
Youngner, a virologist and immunologist, to serve on the Panel.
2/
Where a debarment has been proposed, the Panel provides findings
of fact and a recommended decision for the Debarring Official.
The Debarring Official may reject the findings of fact only if
the Debarring Official determines them to be arbitrary and
capricious or clearly erroneous. The Panel's decision is the
final agency action with respect to other administrative actions
proposed by ORI.
Regulations at 45 C.F.R. Part 76 and 48 C.F.R. Parts 9.4 and 309
govern debarment actions. In accordance with those regulations,
the charge letter alleged these causes for debarment based on the
findings of scientific misconduct:
A history of failure to perform or of unsatisfactory
performance of one or more [grants or contracts]; or
* * *
Any other cause of so serious or compelling a nature that it
affects the present responsibility [of the individual or
entity].
45 C.F.R. 76.305(b)(2), (d); 48 C.F.R. 9.406-2(b)(1)(ii),
(c).
The debarment regulations provide for proceedings that are as
informal as practicable, consistent with principles of
fundamental fairness. However, the respondent must be afforded
an opportunity to appear with a representative, submit
documentary evidence, present witnesses, and confront any witness
the agency presents. The Debarring Official's decision on the
proposed debarment is made after any fact-finding proceeding and
is based on the administrative record. 45 C.F.R. 76.310
through 314 and 48 C.F.R. 9.406-3.
The Panel provides a de novo review. What this means is that a
Panel decision is not a review of what ORI did during its
investigation or whether what ORI found was reasonable based on
the evidence ORI considered. In this case, the Panel held an en
banc 28-day evidentiary hearing during which both sides had an
opportunity to present testimony from witnesses and documentary
exhibits. This hearing was Dr. Imanishi-Kari's first opportunity
to confront and cross-examine witnesses against her and to test
the expert opinions on which ORI relied. 3/ Our decision is
based solely on the evidence admitted into the record before us.
Under the guidelines, the Panel is to determine whether ORI
proved any charges of scientific misconduct, and, if necessary,
to determine the appropriateness of the proposed administrative
actions. The guidelines and the debarment regulations require
ORI to prove scientific misconduct by a preponderance of the
evidence. This means evidence that is more convincing than the
opposing evidence and shows as a whole that misconduct was more
probable than not. 4/
The regulatory definition of scientific misconduct, first
published in 1989, states:
Misconduct or Misconduct in Science means fabrication,
falsification, plagiarism, or other practices that seriously
deviate from those that are commonly accepted within the
scientific community for proposing, conducting, or reporting
research. It does not include honest error or honest
differences in interpretations or judgments of data.
42 C.F.R. 50.102. Findings of scientific misconduct, if
proved, carry serious consequences. Thus, a federal agency
contemplating taking administrative actions against an individual
on such grounds must have a fully adequate basis in law and fact.
The charges here relate to conduct allegedly occurring before
this definition was published. ORI said, however, that it was
charging only intentional and deliberate falsification and
fabrication. It is not disputed that such conduct could be a
basis for a prospective action to protect the integrity of
federal research, even if the conduct occurred before the
definition was published. As we have noted before, however,
"[t]he unquestionable duty of a scientist to seek accuracy . . .
does not necessarily extend to a duty to achieve perfection or
freedom from all inadvertent error." Dr. Rameshwar K. Sharma,
DAB No. 1431, at 13 (1993). Previous rulings in scientific
misconduct cases relating to conduct occurring before the 1989
definition was published have made clear to ORI that charges may
not be expanded beyond that definition to encompass honest errors
or honest differences in interpretations or judgments of data.
During and after the hearing here, ORI sought to expand its
charges beyond those stated in the charge letter, to encompass
conduct that would not amount to intentional and deliberate
falsification or fabrication but which ORI or its witnesses
considered bad practice or bad interpretations or judgments of
data. This raised questions of fundamental fairness.
Dr. Imanishi-Kari could not reasonably have been expected to
respond to charges not previously made, concerning conduct not
mentioned in the ORI Report or practice standards not previously
cited as a basis for a misconduct finding.
ORI also suggested in post-hearing briefing that a previous
decision had set a documentation retention standard for research
data. Contrary to ORI's suggestion, that case did not find
scientific misconduct based on lack of documentation, but was a
plagiarism case which merely referenced a regulatory standard for
record retention under federal grants as support for an inference
drawn from the lack of any original primary data for published
work. Dr. David C. Bridges, DAB No. 1232, at 83-87 (1991). We
also note that the retention requirement is a three-year
requirement, and there is no basis in the record here for
concluding that Dr. Imanishi-Kari had failed to meet it, to the
extent it applied. See 45 C.F.R. 74.21 (1984-86). Similarly,
ORI's reliance on a 1989 publication as establishing standards
for research conducted before that time is misplaced.
Our analysis in this decision evaluates whether ORI proved by a
preponderance of the evidence intentional and deliberate
fabrication or falsification, as charged.
II. FACTUAL BACKGROUND 5/
The Cell paper and its central findings
The paper at issue here, entitled "Altered Repertoire of
Endogenous Immunoglobulin Gene Expression in Transgenic Mice
Containing a Rearranged Mu Heavy Chain Gene," was published in
1986. 45 Cell 247 (April 25, 1986) (Cell paper). 6/ This paper
resulted from an interdisciplinary collaboration between two
laboratories at the Massachusetts Institute of Technology (MIT):
one headed by Dr. Imanishi-Kari and the other by Dr. David
Baltimore. Stipulation (Stip.) 2, 3. 7/ Dr. Imanishi-Kari came
to MIT in 1981 after extensive experience in laboratories in
Finland, Germany, and Japan. Stip. 1; Ex. R31. 8/ Dr. Baltimore
had approached Dr. Imanishi-Kari about collaborating to study
antibody expression in mice after a gene derived from one strain
(BALB/c) was microinjected into a closely related strain
(C57BL/6). 9/
The central finding of the Cell paper was that the introduction
of the transgene changed the antibody repertoire. The Cell paper
reported that antibodies produced by the transgenic mice included
a high frequency of antibodies with the idiotype of the inserted
gene but heavy chains characteristic of the endogenous mice (into
which the gene was inserted). 10/ In order to study this
phenomenon, the authors used both serology and molecular biology.
Dr. Imanishi-Kari was primarily responsible for the serological
work. 11/
The main portions of the Cell paper involved in the charges
before us are Figure 1, Table 2, and Table 3. Figure 1 reported
experiments testing expression of idiotype-positive antibodies in
normal and transgenic mice using anti-allotype reagents (BET-1
and AF6). 12/ Table 2 reported frequency data about idiotype-
positive antibodies from hybridomas, comparing normal and
transgenic mice. Table 3 provided both molecular and serological
information about 34 individual hybridomas (only the serological
information is at issue).
The co-authors and others in the laboratories
The co-authors of the Cell paper, besides Dr. Imanishi-Kari and
Dr. Baltimore, were Dr. Weaver, Dr. Reis, Mr. Albanese, and Dr.
Constantini. 13/ The record shows that there were frequent
discussions between the researchers in the two laboratories about
their experimental results. Dr. Weaver was a post-doctoral
fellow in Dr. Baltimore's laboratory and wrote the first draft of
the paper. Stip. 18; FFCL II.BB.4. He conducted much of the
molecular analyses reported in the paper and assisted with some
of the serological work (particularly the first fusion
experiments). Dr. Baltimore supervised the molecular work and
was actively involved in the preparation of the paper. Dr. Reis
worked in Dr. Imanishi-Kari's laboratory briefly in 1982 and then
from February 1985 to January 1986. Stip. 5; ORI FFCL II.X.3.
Dr. Reis worked closely with Dr. Imanishi-Kari on the serological
work. Mr. Albanese was a research assistant in
Dr. Imanishi-Kari's laboratory and worked on some of the
molecular biology. Stip. 6; ORI FFCL II.A.1, 4. He was not
actively involved in drafting the paper.
In June 1985, Dr. O'Toole came to Dr. Imanishi-Kari's laboratory
as a post-doctoral fellow on a one-year appointment to work on
experiments to extend the findings in the Cell paper. Stip. 4;
ORI FFCLs II.W.2-4. Dr. O'Toole provided some data cited but not
shown in the Cell paper, and read and commented on the paper in
draft form. Cell paper 257-58. Among the other persons working
in Dr. Imanishi-Kari's laboratory at MIT were two then-graduate
students, Dr. Boersch-Supan (1981-85), who also read the draft
and was acknowledged in the Cell paper, and Dr. Maplethorpe
(1981-85), who had no direct role in the Cell paper.
Prior history of this matter
The dispute in this matter began in May 1986 when Dr. O'Toole
reviewed a laboratory notebook (now called R-1) left by Dr. Reis
when she departed and made available to Dr. O'Toole by Dr. Reis
for Dr. O'Toole to use in her work with breeding and testing
mice. Dr. O'Toole was concerned that data on some pages of that
notebook were inconsistent with data in the Cell paper. Dr.
O'Toole copied the pages which concerned her (the "17 pages") and
took them to Dr. Huber (a professor of pathology at Tufts and a
friend at the time of both Drs. O'Toole and Imanishi-Kari). Tr.
1773, 1801 (Huber), 1692-93 (Woodland). Dr. Huber sought the
assistance of two other immunologists who were part of a group of
Boston immunologists that met together regularly for many years,
both of whom had previously had friendly relationships with both
Drs. O'Toole and Imanishi-Kari and both of whom had expertise in
idiotypes. 14/ Tr. 1708 (Woodland), 1775-76 Huber, 2787
(Wortis).
At that point, Dr. O'Toole "did not think that the matter was one
of fraud and wanted to keep it among friends." ORI Br. 11. On
that basis, Drs. Wortis and Huber met twice with Dr. Imanishi-
Kari (Dr. Woodland was unable to attend the second meeting) and
concluded, after discussion and review of data, that the concerns
raised were satisfactorily addressed. Ex. H230; Tr. 1782-83
(Huber). Dr. O'Toole did not agree, and went to MIT with her
concerns. Dr. Eisen at MIT asked her to put them in writing so
that he could understand more clearly. See Exs. H265, R46; Tr.
1962, 1987 (Eisen). Dr. Eisen then met with Drs. Imanishi-Kari,
Baltimore, Weaver, and O'Toole to discuss Dr. O'Toole's concerns.
He felt that Dr. O'Toole raised questions about whether the data
justified the conclusions in the Cell paper and about possible
alternative interpretations. Tr. 1993 (Eisen). He concluded
that the dispute was of a kind "not uncommon in science," and
normally resolved by further work and debate, rather than one
involving misconduct. Exs. H233; R46, at 17; Tr. 1968-69
(Eisen).
investigation of the issues. A panel of three scientists, Dr.
Joseph Davie, Dr. Hugh McDevitt, and Dr. Ursula Storb, was
established to assist in the investigation (NIH Scientific
Panel). The charge to the NIH Scientific Panel was broader than
our role but they considered most of the same scientific issues
presented by ORI before us. 15/ They found errors in the paper
serious enough to call for corrections but "no evidence . . . of
fraud, misconduct, manipulation of data, or serious conceptual
error." Ex. H262 (Letter from Dr. James Wyngaarden, dated
January 31, 1989, at 1). In fact, the NIH Scientific Panel
concluded after an "intensive review" of the raw data in the
notebooks of Dr. Reis, Dr. O'Toole, Dr. Weaver and
Dr. Imanishi-Kari, that it was "impressed by the amount of work
done in support of the studies . . . by the completeness of the
records, and by the abilities of both Drs. Imanishi-Kari and
Weaver to find, accurately interpret, and present data" on the
experiments then three or four years in the past. Ex. H262 (NIH
Scientific Panel Report at 10).
The Subcommittee on Oversight and Investigations of the House
Committee on Energy and Commerce of the U.S. Congress
(Subcommittee), then chaired by Congressman John D. Dingell,
conducted hearings in April 1988, May 1989, and May 1990 relating
to the Cell paper. A subpoena for laboratory data relating to
the Cell paper was issued by Congress in June 1988, and
Dr. Imanishi-Kari submitted her records to NIH in July 1988. See
Exs. H248 and H249. 16/ The Subcommittee requested the United
States Secret Service to conduct forensic analyses (particularly
document examination testing) of some of the laboratory notebooks
of Drs. Imanishi-Kari and Reis. See Ex. H500; ORI FFCL III.J.1.
The NIH investigation was reopened in May 1989. 17/ Ex. H269.
The case was referred to the U.S. Attorney's Office for the
District of Maryland which declined to prosecute. Stips. 83, 84.
ORI issued a 231-page report (with attachments) on October 26,
1994, concluding that Dr. Imanishi-Kari had committed scientific
misconduct in relation to the Cell paper. Stip. 93; ORI Report
passim. The charges against Dr. Imanishi-Kari were set out in a
letter to Dr. Imanishi-Kari, also dated October 26, 1994. Charge
letter passim. On November 23, 1994, Dr. Imanishi-Kari requested
a hearing on ORI's charges against her. Stip. 95.
The case presented before us turns on the forensic attack on the
authenticity of data recorded in the I-1 notebook since ORI has
stated that if the questioned data existed they were sufficient
to support the paper. 18/
III. GENERAL FINDINGS
In this section, the Panel explains how we evaluated the evidence
and, generally, why we do not draw the same inferences as ORI.
The findings we set out here are derived from the record as a
whole and from the detailed analyses of individual charges
addressed in other sections of the decision.
As noted above, several scientific reviews of the 1986 Cell paper
found that, although significant inaccuracies or misstatements
occurred, no scientific misconduct was involved. In reexamining
this case and at the hearing before this Panel, ORI presented
both complex scientific analyses and forensic evidence (not
considered by previous reviewers). ORI used statistical and
document examination techniques to reopen the question of whether
scientific misconduct did occur.
The sheer volume of material presented by ORI was enormous. The
number of exhibits and reports generated over the many years of
investigations and the lengthy hearing process required a massive
amount of time and resources to evaluate fairly. Weighing
evidence is not a mechanical process comparing the number of
pages or hours of testimony for each side; rather, the fact-
finder must assess the quality and probative value of all of the
evidence. This approach is in accord with that of courts
confronting large records. 19/
The main problem with ORI's case was not that more evidence was
needed but that less equivocal and more independently decisive
evidence was required for ORI to carry its burden of proof.
The Panel found that much of what ORI presented was irrelevant,
had limited probative value, was internally inconsistent, lacked
reliability or foundation, was not credible or not corroborated,
or was based on unwarranted assumptions. Of course, we were
unable to describe each and every assessment of evidence
individually because to do so would require a decision of
unmanageable length and complexity without altering the outcome.
20/ Where important, however, we have explained why certain
evidence was disregarded or discounted. We have also explained
generally in the next section why we conclude that (1) the
statistical analyses would support an inference of scientific
misconduct only if the assumptions underlying the analyses were
valid and the other evidence compelling (conditions not met
here); and (2) none of the document examination findings were
meaningful standing alone, and even collectively they were not
direct evidence of any act of fabrication.
Because the history of this case involved a direct attack on
Dr. Imanishi-Kari's honesty, we evaluated her statements
carefully and relied primarily on evidence in the record other
than her testimony, except where she was not contradicted. The
credibility of her testimony before us was bolstered, however,
when much of the evidence in the record, and in particular some
of the document examination evidence, corroborated her statements
and directly contradicted representations made by ORI.
Since neither party's case depended entirely on direct evidence,
each party sought to draw inferences from the evidence in the
record. To evaluate competing explanations of observed anomalies
or data disputes, the Panel was obliged to consider which
explanations are more likely and to weigh the reasonableness of
the inferences which the parties would have us draw. Evaluating
alternative theories of a case and drawing reasonable inferences
from the facts found is a proper and necessary part of any
decision-making process. Were we to decline to do this, on the
grounds that this constitutes speculation (as ORI suggested),
ORI's case would fail entirely.
After examining the entire record, we reached a number of general
findings about why it is not likely that falsification or
fabrication was the cause of any errors or anomalies presented to
us. These findings are reflected in our analyses of individual
charges, but not repeated there:
All of the scientists who looked at the questions raised
about the Cell paper over the preceding decade (at Tufts,
MIT, and on the NIH Scientific Panel) found no evidence that
scientific misconduct had occurred. 21/ While they found
errors in the paper, and the authors published corrections,
the dispute appeared to center on differences about how
judgment was exercised, how experiments might be
interpreted, and whether phrasing in the paper was correct.
Although ORI raised some new or differently-presented
scientific issues before us, these also proved to be largely
matters of interpretation, judgment, and confusing
laboratory jargon.
The one important aspect of the case which was not
considered by previous reviewers is the forensic attack on
the authenticity of some of the laboratory data based on
statistical and document examination methods. However, at
most, these analyses identified some possible anomalies, but
provided no independent or convincing evidence that the data
or documents were not authentic or could not have been
produced during the time in question.
Most of the data allegedly fabricated were not even included
in the Cell paper. Two-thirds of the data in the I-1
notebook were not challenged, including much of the original
data that were published.
Often, ORI found that Dr. Imanishi-Kari had misrepresented
data, without fully understanding how she had represented
data. We examined the Cell paper and her notebooks as a
first step in analyzing whether the experiments and results
were misrepresented.
Many of the questioned notebook pages contain material that
is not helpful in supporting the conclusions in the Cell
paper. 22/ ORI's own expert, Dr. Gilbert, testified that
"[p]eople provide, when they fake experiments, they provide
data that's generally too accurate. They provide data that
is too sharp." Tr. 1481-82. Yet in many cases the results
included on the questioned pages were conflicting or bizarre
in ways more likely to raise than resolve scientific
questions. Even if Dr. Imanishi-Kari were cleverly avoiding
too perfect a look, there is no demonstrated reason that she
would create bizarre and conflicting results which could
only call attention to problems rather than mask them.
Furthermore, in many instances, it was as hard to comprehend
how particular alleged anomalies could have been created by
any fabrication scenario as it was to understand how they
could have occurred as errors or artifacts in the
experimental process.
A degree of sloppiness in recording and maintaining data
certainly may warrant criticism of Dr. Imanishi-Kari's care
in recordkeeping (tempered with a recognition that standards
in this area have evolved since the mid-1980's). We find it
completely illogical, however, that Dr. Imanishi-Kari would
retain intact the most central data complete with flaws and
then intentionally create false data on more peripheral
points that are equally imperfect. 23/
Many of the most troubling forensic attacks are mounted
against the most trivial or peripheral data. For example,
the "January fusion" controversy, which was one of the most
troublesome, centers on the data from transgenic fusions not
used for any purpose whatsoever. The only explanation
offered for why such data would be fabricated was that the
addition of transgenic fusion data might lend verisimilitude
to a related normal control fusion used as one part of the
negative results reported on normals in Table 2 but about
which little direct forensic evidence was offered. See ORI
Br. 83.
ORI's descriptions of the forensic findings were not always
dependable. For example, as described by ORI, one type of
Secret Service analysis seemed to provide support (albeit
limited) for ORI's position on two important issues: what
coat was used for a certain isotyping assay and whether
certain control results related to a particular allotyping
assay or to a later retest. The actual results, however,
were not as described and were consistent with (indeed,
arguably substantiated) Dr. Imanishi-Kari's version of
events (which was also corroborated by other evidence).
ORI's descriptions of experimental results were similarly
not reliable. For example, ORI's findings relied on a
definition of "double producers" (a term used in the paper)
that was not confirmed by any of the witnesses, even ORI's
own independent experts. In evaluating whether double
producers existed, ORI treated +/- results on an assay read
by eye as "positive scores" definitively detecting double
producers. The results were equivocal, however, and were
given undue significance by ORI. Frequently, ORI
interpreted the same or similar results one way for one
purpose and another way for another purpose. This
circularity in ORI's reasoning made it difficult to sort out
ORI's various arguments.
In some areas, ORI's attempts at establishing a possible
motive for fabrication or falsification requires very
convoluted reasoning. For example, Dr. Imanishi-Kari is
alleged to have fabricated a page with very poor results
using a reagent (BET-1) which ORI charged did not work as
well as reported, in order to bolster a story that BET-1
worked poorly for a while but later worked well in some
other instances. See ORI Br. 41-48. On the whole, most of
the alterations for which no reasonable motivation was
adduced look much more like the marks of untidy "real life,"
than like suspicious efforts at some intentional laundering.
The Cell paper as a whole is rife with errors of all sorts.
Many of them are obvious to a careful reader and in no way
strengthen the authors' arguments. The authors addressed a
number of these errors in published corrections (including
an overstatement of the degree of specificity of BET-1 in
relation to Figure 1 and clerical errors in Table 3).
Exs. H2 and H3. There are additional errors evident on the
face of the paper, some of which, despite all these years
and layers of review, have never previously been pointed out
or corrected. 24/ Responsibility for the pattern of
carelessness in writing and editing of this paper must be
shared by all the participants, including the main drafter
(Dr. Weaver), the leading collaborators who shaped the
communication and drafting process (Dr. Baltimore and
Dr. Imanishi-Kari), the contributing authors who failed to
catch errors in their areas of expertise, those who read the
paper in draft form (including Dr. O'Toole and Dr. Wortis),
and the reviewers and editors who failed to pick up errors
in the original submitted text of the paper. While a high
rate of careless errors is no defense to intentional
falsification and fabrication, the presence of so many
pointless mistakes at least raises a question whether the
mistakes singled out as intentional (because they arguably
favor the authors) really represent conscious efforts to
deceive.
One of the strengths of the Cell paper was the combination
of serology and molecular biology in studying the effects of
the insertion of the transgene on the murine immune system.
However, the same interdisciplinary collaboration between
two laboratories that produced this strength also presented
apparent obstacles to communication and risks of
misunderstanding. In a number of areas, poor communication
may have contributed to confusion in interpreting and
presenting experimental results.
Most of the witnesses with personal knowledge of contested
events testified on behalf of Dr. Imanishi-Kari. While ORI
suggested that Dr. Imanishi-Kari's witnesses might be
biased, ORI did "not contend that [they were] lying." ORI
Reply Br. 22. Conflicting accounts of the events by ORI's
witnesses were uncorroborated.
Finding intentional and deliberate falsification and
fabrication as alleged by ORI would require a conspiracy of
authors and an intentional coverup by those to whom
Dr. O'Toole turned at MIT and Tufts. 25/ Yet, it is
unlikely that Drs. Weaver and Baltimore conspired with Dr.
Imanishi-Kari to create results used in the Cell paper when
that paper's conclusions significantly diverged from some of
their prior research and theories and presented surprising
results, rather than simply bolstering their prior work.
While Dr. Imanishi-Kari's colleagues might judge her more
generously based on friendship, there is no basis in the
record to suggest that all of these scientists would
jeopardize their own careers by lying to save hers. 26/
If Dr. Imanishi-Kari had plotted to publish false data in
the Cell paper or knowingly to interpret the data in
misleading ways, it seems hardly likely she would hire
Dr. O'Toole to extend the work reported in the paper, have
her review a draft of the paper, and give her access to a
notebook containing much of the problematic data.
Much of ORI's attack on the Cell paper seemed disconnected
from the context of science at the time the published work
was performed. We sought to evaluate Dr. Imanishi-Kari's
motivation and actions with as much understanding as
possible of the state of knowledge, preceding work, and
expectations of the authors as reflected in the progression
of their actual scientific work.
This context informs our consideration of specific charges, and
our evaluation of credibility of testimony and other evidence
throughout the decision.
Contrary to what ORI argued, we need not distinguish between the
parties in determining what inferences to draw. ORI argued that
its "account of what likely happened must necessarily be
speculation," since no eyewitnesses to any misconduct had been
found and "no confession of guilt" had been made. ORI Br. 19,
n.6. On the other hand, ORI implied, Dr. Imanishi-Kari could
have testified about precisely what she did do, so that her
"after-the-fact rationalizations" must be disregarded as "self-
serving and designed to mislead." Id. This approach thus begins
with an assumption that Dr. Imanishi-Kari is guilty of misconduct
and anything less than a "confession" of her methods constitutes
rationalization. The opposite assumption, however, does not lead
to a conclusion that all she has to do to set the record straight
is to tell the truth. An innocent person might well not know
precisely how anomalies came to exist in data generated and
organized years earlier. For example, the claim that certain
data display odd statistical patterns (when analyzed) arose only
in 1990, and Dr. Imanishi-Kari might quite innocently be unable
to recall if anything unusual occurred during the experiment done
over five years before or to test equipment or reagents to
ascertain what artifacts might have arisen. Similarly, when
questions are raised years later about why the intensity of ink
on two counter tapes might be different, Dr. Imanishi-Kari might
well be unable to recall precisely what printers were used, when
ribbons were changed, or even whether a particular counter tape
might have been mislabelled or misfiled. As a result, both
parties were equally compelled to explore alternative
explanations that might account for the present state of the
experimental record. No unfavorable inference can reasonably be
drawn from Dr. Imanishi-Kari's inability to provide definite
information about how each perceived anomaly occurred.
The Panel found that the "notebooks" and raw data were often
incomplete and difficult to interpret with certainty, even by
Dr. Imanishi-Kari. This is not particularly remarkable, in and
of itself. For someone who did not conduct the experiments to
parse through the raw data of another scientist is likely to be
extremely difficult even when the data are current. 27/ Data
from many years ago are even less likely to be complete and
transparent upon review. 28/
In some respects, a parallel to the difficulty of after-the-fact
interpretation of one scientist's data by an outside observer
arose at the hearing with respect to the original ink analysis
data of the Secret Service. Much of the raw data are missing or
destroyed at this point (many of the actual ink analysis plates
have been broken or have faded). Mr. Stewart, one of the
document examiners, testified that he does not always prepare
work sheets to document his ink analyses, relying sometimes on
his own "cryptic" notes. Tr. 3762, 4056. Such recordkeeping
decisions, he stated, are "really up to the examiner." Tr. 4056.
Work sheets recording the original reading of the plates by the
examiners are often too incomplete to support conclusions in
themselves or to permit another ink analyst to independently
review their interpretation. He testified that: (1) he knows
from his report the conclusions he drew from the original plates;
(2) while the work sheets may not be perfect, they are enough for
him to explain his interpretations; (3) no one else ought to even
try to interpret his work from the sheets (instead they ought to
take samples, rerun the experiments, and do their own analysis);
and (4) in light of the critiques and the damage to the
originals, he redid the critical ones and they confirm his
interpretations. Tr. 3926-28, 4040-62, 4072-73, 4075-76. We
note that Dr. Imanishi-Kari has long suggested that her
questioned experiments could be rerun by investigators to verify
that the reported results would be obtained and that she would be
willing to let somebody with doubts spend time in her laboratory
to repeat those experiments. See, e.g., Ex. H245, at 6. As far
as we know, this proposal has never been accepted. 29/ However,
the point here is not that the ink analysis results were
incorrect or that they were not verified by the later retests,
but that after-the-fact interpretations of another scientist's
records are fraught with difficulty.
For example, although the Secret Service examiners knew at the
time of their work that they were preparing for litigation
(unlike Dr. Imanishi-Kari), their records contain alterations of
the results or omissions of important information. 30/ Tr. 4065-
72, 4075-76, 4081 (Stewart); Exs. H530, H531, H533. 31/ Just as
Dr. Imanishi-Kari has testified that she is able at times to
interpret notations that do not suffice for others to reconstruct
what she did or how she exercised her judgment in constructing an
experiment, the examiners testified that they could reconstruct
what they did even from incomplete records, and they made choices
that shaped their experimental design. 32/ These observations do
not impugn the validity of the Secret Service findings. We do
not infer that the document examiners were incorrect in
explaining what they did, or in their exercise of judgment in
their tests. Overall, however, these observations highlight the
fact that records of scientific experimentation may be opaque to
any one but the researcher and, after a number of years, even the
researcher may be forced to reconstruct what the researcher
"must" have done or meant. The point is that any scientist may
sometimes have to extrapolate from incomplete records to
reconstruct how work was done and may continually have to
interpose judgment in deciding what tests to run and how to
interpret them, and we must allow for that in reviewing
Dr. Imanishi-Kari's retrospective explanations of results that
may not be clear on their face.
We recognize that some of the apparent anomalies and
peculiarities in the records may be impossible to explain fully
at this point. No hearing process can absolutely rule out the
possibility of improper action. Here, in order to sustain the
charges against Dr. Imanishi-Kari, we would have had to find that
ORI proved that it was more likely than not that intentional
fabrication or falsification by Dr. Imanishi-Kari was the cause
of the anomalies, and we do not find that ORI met this burden as
to any of the charges.
IV. OVERVIEW OF FORENSIC EVIDENCE
A. Statistical analyses
ORI presented statistical analyses and testimony to support its
charges of fabrication with respect to certain sets of data (none
of which was used in the Cell paper). We note that the issue
before us is not whether statistical analyses provide a useful
tool for examining allegedly fabricated or falsified data.
Rather, the question is whether, in this particular case, ORI's
statistical analyses provide reliable evidence of fabrication or
falsification. We address ORI's analyses of specific data sets
in the context of individual misconduct charges below. Here, we
state general conclusions about why we do not find the
statistical analyses to be reliable, credible, probative evidence
of fabrication of data.
Based on our examination of the record as a whole (including our
own observations of the data), we conclude that--
ORI did not establish that (even assuming the statistical
analyses are valid) it is reasonable to infer from that
evidence alone that the analyzed data are fabricated. While
ORI's statistical expert who did the analyses, Dr. Mosimann,
gave his opinion that the data were fabricated, we find that
his testimony was on the whole less persuasive than the
conflicting evidence. Contrary to what ORI argued, he did
not have more relevant experience than Dr. Imanishi-Kari's
expert (Dr. Speed), who testified without compensation and
who presented an opposing opinion. 33/ ORI's other
statistical expert (Dr. Barron, a colleague of Dr. Mosimann)
testified that he would not reach a conclusion of
fabrication based on the statistical analyses alone;
instead, Dr. Barron stated that "if the scientific and
forensic evidence is compelling, the statistical evidence
[in the ORI Report] . . . corroborates it." Tr. 5019
Statistical results are valid only if based on valid
assumptions. ORI did not establish through a preponderance
of the reliable, credible evidence that the assumptions
underlying its statistical analyses were valid. The
testimony about the assumptions presented by ORI was
conclusory, and generally had no basis in any independent
empirical analyses nor any clear theoretical foundation.
The assumption underlying part of the analyses was an
expectation of randomness in fusion experiments, but Dr.
Mosimann's previous published work indicates that this
assumption is valid only if certain experimental conditions
are met. Unrebutted testimony indicates that it would be
unreasonable to expect these conditions to apply.
Generally, ORI did not relate its assumptions to the
specific experiments at issue. ORI relied primarily on
analyses of unquestioned data sets as "controls" to
establish its underlying assumptions, but this reliance is
misplaced, for reasons explained below. In particular, we
find that the unquestioned data sets are simply not
comparable to the data sets that ORI questioned.
Even if we were to find that ORI's underlying assumptions
were valid, we would not find ORI's statistical evidence on
the whole to be persuasive. ORI did not establish that all
of the techniques it used were commonly accepted statistical
techniques, nor that it applied those techniques in an
appropriate way. Dr. Imanishi-Kari established that other
reasonable statistical analyses could lead to different
conclusions.
The fact that ORI's statistical calculations were in most
respects accurate is irrelevant in light of ORI's failure to
establish either the validity of its methodologies as applied
here or the reasonableness of the inferences it drew from its
analyses. Similarly irrelevant in a contested case such as this
is the fact that statistical analyses were used in investigations
that resulted in uncontested findings of misconduct.
B. Document examination methods
The forensic examinations conducted by the Secret Service on the
data in the I-1 notebook were presented by ORI to support many of
its charges. We address ORI's analyses of specific pages from
the I-1 notebook in the context of individual misconduct charges
below. In this section, we discuss the nature of the document
examination tests undertaken, the limitations of those tests
generally, and the validity of the underlying assumptions.
Finally, we state general conclusions about why we do not rely on
the document examination findings as definitive or reliable
evidence of fabrication of data in this case.
Overall, the Panel found the Secret Service document examiners
who testified at the hearing, Mr. Stewart and Mr. Hargett,
professional in demeanor and informative as to the techniques
they used. We generally relied on the factual information which
they presented concerning the results of their experimental tests
of the documents and the nature of the analyses performed. The
examiners made clear that this case was unique in their
experience, involving hundreds of hours of work over a number of
years. Tr. 3559-60, 3983. 34/ There was no evidence that any of
their previous cases involved reviewing laboratory notebooks of
scientists. 35/ This case was unlike many challenges to the
authenticity of standardized documents (such as birth
certificates or currency), in that the counter tapes and other
items used to create the I-1 notebook (pads, pens, notebook
pages) were authentic materials available in the laboratory.
Instead, the issues raised about the documents went to when they
were produced. The forensic document examination evidence is
thus limited in focus to questioning the time at which some of
the pages in the I-1 notebooks were created (and in a few cases,
the time at which the counter tapes themselves were generated).
36/ Further, the Secret Service did not testify that any
individual test conclusively dated any data or pages. Mr.
Stewart emphasized instead that, while none of the results of any
one test alone might cause him to find fabrication or
falsification, the convergence of the results demonstrated that
the conclusions were supported. Tr. 3931. While a series of
independently meaningful methodologies yielding mutually
supportive results may be reinforcing, it is not necessarily the
case that a series of tests, each admittedly insignificant on its
own, can be added together to claim significance.
The Panel found the Secret Service's conclusions to be
unpersuasive because:
(1) they depended on the erroneous assumption that the I-1
notebook was created as a contemporaneous, chronological
record of experiments as they occurred,
(2) they were based on comparisons with other laboratory
notebooks that did not establish a standard or norm against
which the I-1 notebook could fairly be measured,
(3) they were reached in a vacuum of information about the
kind of experiments done in Dr. Imanishi-Kari's laboratory
and the substantive nature of her scientific work which
influenced the way her data were organized and presented,
and
(4) each of the analyses on which they were based had
inherent limitations (as the examiners themselves testified)
that undercut their reliability for the purpose of
supporting the conclusions which ORI reached. 37/
We discuss each of these reasons in more detail below.
The data in the I-1 notebook were organized over a number of
months and not compiled into notebook form until much later.
The I-1 notebook did not purport to be put together in this
form at the time of the experiments.
Since the question of time is central to the document
examination, the Secret Service's conclusions were especially
dependent on an understanding of when the I-1 notebook pages were
"purportedly" created. Mr. Hargett testified that the
understanding on which he based his work was as follows:
[T]he I-1 notebook was supposed to have been created in
1984, contemporaneously with experiments that were being
conducted during that period of time. And that the
notations appearing in this notebook, and the results of
experiments being run, were the results of testing that was
being conducted at that period of time.
Tr. 3499-3500. Further, he understood that the notebook was
compiled chronologically in the sequence in which the experiments
were done, and that dates on pages purport to be "within a fair
amount of time" of the dates on which the experiments were
conducted. Tr. 3500. Consequently, in examining the notebook,
the examiners would have considered as notable any deviation from
these expectations.
The examiners' expectations appear to have been based on their
reading of a letter from a former counsel for Dr. Imanishi-Kari
responding to a request from the Subcommittee to indicate if the
laboratory notebooks were "created contemporaneously with the
scientific experiments" and "prepared prior to the submission of
the Cell paper." Ex. H267, at 2. The March 1989 letter confirms
that this assumption is correct, and on that basis the examiners
expected all the pages to be "contemporaneous." However, the
author goes on to state that "[i]n this context" he has "some
difficulty interpreting the word contemporaneous.'" Id. He
then explains that:
Most of the of the original data presented in the Cell paper
are radio immuno assays . . . . Construing the word
contemporaneous strictly, the only entries in the Notebooks
created contemporaneously with the scientific experiments
are the gamma counter printouts . . . and the x-rays. All
hand written entries were made after the conclusion of a
particular experiment. Construing the word contemporaneous
in the broader sense, it is fair to say that all of the data
presented in the Cell paper were assembled contemporaneously
with the scientific experiments and placed in the Notebooks
in a timely fashion.
Id. (emphasis added). He also stated that the "data presented in
the Cell paper and recorded in the Notebooks were prepared prior
to the submission of the Cell paper." Id. at 3. He noted that
much of the data in the notebooks were not presented in the Cell
paper, being confirmatory or ancillary work, and that other
notations were entered after the paper was submitted. He
highlighted "in particular" some of the later notations. Id. In
addition, he pointed out that not all data are normally preserved
in a laboratory notebook. Id.
The language of the letter is ambiguous but was apparently
interpreted by the Secret Service examiners to mean that the
notebook existed in essentially its present form before the Cell
paper was submitted. The lawyer appears to have been focusing
mainly on the point that Dr. Imanishi-Kari did not create data
retrospectively to justify her reported findings but rather used
data created at the time by the gamma counters. However, the
reference to "data" having been "assembled" contemporaneously "in
the broader sense" can also be interpreted as consistent with
collecting the counter tapes into files, without necessarily
implying that they were immediately pasted onto pages of a
notebook. Also, the letter does not say that everything in the
notebooks except the listed notations was put there before the
Cell paper was submitted, only that the data published in the
paper were assembled prior to that.
Dr. Imanishi-Kari testified about her practices in collecting and
assembling data, about the source and meaning of dates in her
data records, and about the creation of the I-1 notebook. Her
testimony was corroborated by the observations of other witnesses
and supported by our review of the physical evidence. The
language of the lawyer's letter, while not evidencing a clear
explanation of these details (the significance of which may not
have been evident at the time) is consistent with her
descriptions as are her statements earlier in this matter. We
describe this process below and explain why we find it generally
credible that I-1 notebook was the product of this kind of
process (and hence never intended to be taken as
"contemporaneous" in the narrow sense in which the Secret Service
understood it).
At the time of the experiments later used in the Cell paper,
Dr. Imanishi-Kari kept a brown spiral notebook (of a kind common
at MIT) as an ongoing record of protocols and information such as
dates of certain fusions and assays. Tr. 5132-35, 5144, 5177-84,
5256-57 (Imanishi-Kari), 1699 (Woodland). As a rule, when an
assay was run and counter tapes were generated, she noted the
reagents or materials used in the experiment on the counter tape
itself and the tapes were either retained in loose form around
her office or placed in manila folders. 38/ Tr. 5123-24, 5131.
She did not necessarily date the counter tapes, and indicated
that she infrequently put dates on them, but was able to identify
them based on the reagents and samples tested. 39/ Tr. 5122-23,
5132, 5193, 5256.
She would further organize the data at various times, often
substantially removed from the date when they were generated. 40/
The data could be entered on a page either by pasting in the
entire tape, or by cutting the tape into strips containing only
the counts per minute column, or by copying the information on
counts per minute by hand. 41/ Tr. 5080, 5124-25, 5128-29.
These organizational efforts were sometimes undertaken when she
was preparing a paper or grant or needed the data for a specific
purpose; at other times simply when she "couldn't stand the mess"
in her office or did a general "spring cleaning." R. Br. 4; Tr.
5124-28. The latter included organizing data when Dr. Reis left
the laboratory in January 1986 and when Dr. Imanishi-Kari herself
moved to Tufts in July 1986. R. Br. at 4; Tr. 5126-27
(Imanishi-Kari), 2545 (Reis).
A significant aspect of Dr. Imanishi-Kari's work was that
frequently data from different assays on the same or related
samples had to be compared. Such data might be pasted in strips
on a single page, cut in pieces, or handwritten in order to line
up related results. As a result, experiments from very different
dates might be reflected on the same pages. Tr. 5075-81, 5106-
07, 5127. Furthermore, it is clear from examining I-1 (and other
notebooks) that the paper was drawn from many sources including
writing on looseleaf sheets, removing paper from pads glued at
the top, and tearing pages out of one or more spiral notebooks,
so that one set of assays is not necessarily all organized on the
same kind of paper. See, e.g., I-1:83-87. Even when the data
were on pages with notations (sometimes on groups of pages which
were numbered consecutively), the pages were not necessarily
placed in a single notebook form.
In general, Dr. Imanishi-Kari's dating appears to have been
erratic. 42/ She attributed little importance to the dates on
which particular assays were run (as opposed to mouse screening
for which accuracy in dating had significance). Tr. 5123-24,
5151-55. The dates she wrote down when she organized the tapes
were estimates, sometimes retrospective, and might refer to any
of several points in experiments (which might extend over a
considerable time period, as, for example, when a fusion was
performed, cells were grown up, supernatants were recovered, and
several assays were run). See Ex. H103, at 70-71. At best, the
dates might generally differentiate sets of assays, but they do
not purport to specify the day a particular counter tape was
generated or that a page was composed. Ex. H286, at 6. She
relied at times on the dates recorded in protocols in her spiral
notebook in making or correcting a "guesstimate" date for
experimental results. Tr. 5222-23, 5256-57, 5263-64.
Dr. Baltimore testified that he knew of Dr. Imanishi-Kari's data
collection and recordkeeping practices at the time of their
collaboration and often discussed the ongoing work in her office
and reviewed her data. Tr. 2071. He described this as follows:
She had folders with notes in them. She had notes on her
desk, in her drawers. She had lots of computer print-outs -
- not computer, teletype print-outs. . . . which described
the data from a whole variety of experiments. Some of
them were yellowing on her window sill. They were all
over. . . . It was quite remarkable that in that seeming
chaos when a pointed question came and I said let's look at
the data and see what the numbers look like and try plotting
them out, whatever. As fast as if she had a notebook in
front of her she could find the relevant material and we
could go over them and there was never an issue. I might
say that that is not unique in my experience. I've seen
other people who can do that. But it's a rare talent.
Tr. 2071-72; see also Tr. 4578 (Igras), 2374-75, 2404-05
(Weaver), 2565 (Albanese), 1855-56 (Boersch-Supan). The uniform
observation that Dr. Imanishi-Kari did not promptly record or
organize data into notebook form, but rather collected raw data
in loose piles or manila folders, is uncontradicted by the two
ORI witnesses who worked in the laboratory with her--Dr. O'Toole
and Dr. Maplethorpe. Not one witness testified to observing
Dr. Imanishi-Kari entering data into a looseleaf notebook (like
I-1) while recording her experiments.
It is undisputed that the compilation of the loose pages into
notebook form was undertaken prior to their being provided to NIH
in July 1988, following a subpoena from the Subcommittee. The
compilation was done at the suggestion of an attorney who advised
her to put her data together so that others could better
understand them and so nothing would be lost. Tr. 5142-43
(Imanishi-Kari); Exs. H103, at 51; H248; H249. Dr. Imanishi-Kari
testified that the attorney suggested that she organize her notes
into three-ring binders, like those utilized by Dr. O'Toole and
Dr. Reis, after observing that Dr. Imanishi-Kari's notes included
loose pages and pieces of counter tape maintained in manila
folders. Dr. Imanishi-Kari testified that, following his advice,
she did not make changes or add information to the pages at that
point, other than reattaching tapes that came off while making
copies. Tr. 5143-44, 5149.
At that point, Dr. Imanishi-Kari disassembled her spiral notebook
and dispersed the contents through I-1 in an effort to connect
the protocols and summaries in the spiral notebook with the raw
data from related experiments. Tr. 5142-47. In the process,
experiments were grouped together topically, which resulted in a
rough progression of the research but not a strict chronological
presentation. Id. 43/
It is not believable that Dr. Imanishi-Kari intended to convey to
NIH and the Subcommittee a false representation that she placed
her data in a bound notebook in final form concurrently with the
dates on which she conducted experiments, when she knew that
virtually anyone who had set foot in her laboratory would be able
to contradict that assertion. Also, many people, including Dr.
Maplethorpe who plainly had no interest in lying to benefit her,
had seen Dr. Imanishi-Kari's spiral notebook in its prior form.
Tr. 948 (O'Toole). In addition, pages submitted to NIH in xerox
form before the date when Dr. Imanishi-Kari testified that she
interleaved the spiral notebook with other loose pages to create
the I-1 notebook show those pages with the spiral binding intact.
See, e.g., Ex. H250. It is unlikely that she would submit data
to NIH in one form and then only a few months later intend to
mislead NIH and the Subcommittee into believing that they had
always been in another form.
ORI acknowledged in its proposed FFCLs that the I-1 notebook "may
have been assembled well after an experiment was conducted, or
certain notebook pages could have been transcribed from scraps of
paper or other fragmentary sources well after the experiment was
carried out." ORI FFCL XII.E.2. ORI continued to deny that this
process could explain all the dating mistakes because five pages
(I-1:30, 41, 42, 43, and 113) were shown by a "confluence" of
techniques to have been produced on "the same pad, with the same
ink," and with impressions (from indentation analysis) showing
they were all created in 1986 but dated in 1984. However, this
assertion misrepresents the significance of the forensic
findings, since, as we discuss below, the techniques relied on
are not able to identify a single pad or pen as the source of
these documents or to ascertain with certainty the order in which
these pages were created. Even were the pages written in 1986,
this would not eliminate the possibility that the data were
collected in 1984.
ORI also argued that Dr. Imanishi-Kari's explanations were
inconsistent with earlier descriptions of experiments by
Dr. Imanishi-Kari which refer to the dates which appear on pages
in the I-1 and R-1 notebooks, allegedly implying that at that
point Dr. Imanishi-Kari took the dates on the pages more
seriously. ORI Reply Br. 3, n.4, referencing Ex. H245 (Letter
from Dr. Imanishi-Kari to Dr. Bick in 1988). However, this is
not inconsistent with Dr. Imanishi-Kari's practice of using the
dates loosely to identify and distinguish experiments without
placing much importance on the specific day on which a particular
sample was run through the counter. Also, since it appears that
the page numbers were put on later, referring to dates may have
been the only way to distinguish similar experiments in the
notebook in her letter to Dr. Bick. Thus, the letter does not
support ORI's inference that Dr. Imanishi-Kari's description of
her practices in record-keeping and data organization changed
after she learned of the Secret Service's findings. 44/
Notebooks of other MIT researchers do not establish a
standard by which the I-1 notebook can be judged fairly.
The Secret Service examiners testified that, in evaluating the
authenticity of a document, it is critical that a "comparative
norm" be established against which to judge the "normalcy" of the
questioned document and to weigh the importance of any deviation.
Tr. 3613 (Stewart), 3229-30 (Hargett). The document examination
work began with only three laboratory notebooks, all belonging to
either Dr. Imanishi-Kari or Dr. Reis (currently in the record as
I-1, I-3 and R-1). Consequently, the examiners had nothing with
which to compare these notebooks except each other. Tr. 3215,
3227 (Hargett) (We "didn't know what researchers' laboratory
notebooks were to look like, quite frankly . . ." Tr. 3229
(Hargett)). The examiners requested that the Subcommittee obtain
additional examples of notebooks from MIT for the relevant time
period. The Secret Service then received 26 notebooks produced
by various MIT researchers and used these for comparison. 45/ Tr.
3617 (Stewart).
However, Mr. Stewart noted that establishing a comparative norm
is sometimes difficult and that "this case is an example of one
that was difficult to do." Tr. 3613. We strongly agree that
ascertaining any norm for a laboratory notebook based on the
assortment of submissions called "notebooks" in this case is
indeed difficult, if not wholly futile. Some submissions conform
to the mental image that the phrase "laboratory notebook"
generally evokes, that is, they are indeed bound notebooks with
numbered pages proceeding in evident chronological order, or at
least looseleaf notebooks in some semblance of order. However,
many others consist of simple manila folders with loose papers
and tapes and a few scribbled notes and with dates in no evident
order and years apart, or of pieces of partially-used pads. The
I-1 notebook (and others from Dr. Imanishi-Kari's laboratory)
seems to fall between these two extremes.
The problem of determining what range of practices in recording
laboratory data would be considered authentic as opposed to
outside the norm is dramatically different from the sort of
document authentication issues normally presented to the Secret
Service. The usual approach is simply to use as a standard a
document about which no questions of authenticity are raised.
A standard could be handwriting of an individual, a standard
could also be a genuine currency, it could be a genuine
document of some type, perhaps a birth certificate, it could
be a genuine credit card.
Tr. 3556 (Hargett). When asked how to determine a comparative
norm in a situation where "there might be many kinds of documents
that would be considered genuine," Mr. Hargett testified as
follows:
Let me take it back to a typical case that we would work,
let's say. Let's say it is a false identification case.
Where we have to determine whether or not certain
identification is genuine. It's important for us to go back
to the manufacturer of that genuine document, and not only
we receive that genuine document, but also receive any
changes that have been made to that document, because we
don't know, for sure, what variation of that genuine
document we may be comparing against the questioned
document.
Tr. 3560 (Hargett). In this case, the examiners ultimately
relied on representations made to them that the other notebooks
which they received as "samples" from other MIT researchers were
"typical" and "unquestioned." Tr. 3562 (Hargett). However, the
one fact which emerges most clearly from a review of the
"notebooks" in the record is that researchers here employed all
sorts of idiosyncratic methods to record data. While the other
researchers' work may well be unquestioned, in that no one has
suggested any reason to question them, we have no basis to
presume, for example, that dates in other notebooks more
accurately represented dates on which those experiments were
conducted. 46/ Certainly, none of the notebooks can be described
as "typical" of any researcher's products and, to a large degree,
there simply cannot be said to be any "norm." Cf. Tr. 3863
(Stewart) (no one form became the norm).
The initial use made of the comparison notebooks was in relation
to "trends" observed in the I-1 notebook. Some of the
observations were that counter tapes were cut into small pieces
and moved from one location to another, that changes were made to
dates, reagents, or other notations, and that some pages
contained writing from more than one color of pen or counter
tapes that differed from each other in color or intensity of ink.
Tr. 3603-04 (Stewart), 3228-29 (Hargett). Some of the same
problems were found in the R-1 notebook, which led the Secret
Service to disregard it as a "norm." 47/ Tr. 3614 (Stewart).
Yet most of the same observations also could be made about other
researchers' notebooks to a greater or lesser extent. 48/ Tr.
3863 (Stewart).
Finally, it is not evident that a norm based on notebooks from
MIT in the mid-1980's is relevant to evaluating the legitimacy of
Dr. Imanishi-Kari's methods of data collection and recordkeeping.
Dr. Imanishi-Kari's practices for recording data would not
necessarily have been shaped by MIT laboratory culture, since she
had already worked for a number of years in laboratories in
Europe and elsewhere which may have had different standards. No
evidence was presented that she received any instructions from
MIT regarding acceptable methods of recording or preserving data.
Therefore, we do not find evidence of a standard for laboratory
notebooks that would apply to expectations for her records.
The Panel concludes that the Secret Service did not have a basis
to establish a comparative norm against which to evaluate
Dr. Imanishi-Kari's notebooks.
The other researchers' notebooks and counter tapes used by
the Secret Service are a substantially incomplete set of
those produced in the laboratories at the time.
The Secret Service examiners operated under the assumption,
admittedly not verified, that they had obtained most of the
notebooks generated during the relevant time in the MIT
laboratories involved. Tr. 3503-04 (Hargett). 49/ However, it
is clear on the record before us that not even the larger sample
of about 60 notebooks which were eventually obtained, and
considered at least to some extent in the document examination,
constitutes even close to a complete record of the way data were
recorded then, since only those which were still available from
MIT in 1989 or 1990 were obtained. Tr. 3864-66 (Stewart). 50/
In fact, MIT Provost Deutch informed the Office of Scientific
Integrity (OSI, ORI's predecessor) in 1989 that "the general
practice in research groups which were likely to use [gamma
counters] . . . is for students and postdocs to take their
laboratory notebooks with them when they depart from MIT.
Accordingly, we do not have access to the universe of past
laboratory notebooks." Ex. H278, at 5. He further indicated
that it was not feasible for MIT to seek information from persons
no longer associated with MIT. Id.
The Secret Service concluded that its sample nevertheless
represented an adequate selection of the notebooks. ORI argued
that this was sufficient because the notebooks represented 12
different researchers and there was testimony that only 15
researchers "regularly used the three counters on the first
floor" laboratory, while others in the building used these
counters rarely. ORI Br. 64-65, citing Tr. 5107 (Imanishi-Kari),
4587, 4611 (Igras). However, this calculation misstates in
several ways the number of researchers whose notebooks might have
contained relevant counter tapes.
First, the testimony was that 15 people from the first floor were
regularly using the counter machines for similar types of
experiments at any one time. Tr. 4587 (Igras). The relevant
time period covered several years during which it is clear that
turnover occurred, in students and others who might work in the
laboratory for relatively short periods. The record indicates
that the cumulative number of researchers using the machines
during the period was considerably more than 15. Second, while
others in the building may have used the first floor counters
less often, that does not mean that they did not have access and
make some use of them so that their notebooks may have had some
of the relevant counter tapes. Third, no evidence was presented
that, for those researchers who were represented among the more
than 60 notebooks ultimately obtained, these were all of the
notebooks which they generated during the relevant time period.
The Panel concludes that the "notebooks" reviewed by the Secret
Service did not represent a complete universe of notebooks
created in MIT during the relevant period.
The Secret Service did not have any information about the
scientific significance of any of the materials they
reviewed and hence attributed unwarranted suspicion to
characteristics of the data for which there were scientific
explanations.
The Secret Service examiners made very clear that they conducted
all their examinations without inquiring into the substantive
science or laboratory techniques related to the data in the I-1
notebook. Tr. 3497-98 (Hargett), 3601-02 (Stewart). This
approach was intended by the Secret Service examiners to insulate
them, in order to conduct their tests objectively, without
preconceptions about the significance of particular experiments
or pages. 51/ However, without interviewing the persons who
generated the data or compiled the notebooks, the examiners made
assumptions about what would be expected in the notebooks. They
operated in an almost complete vacuum of information about the
nature or meaning of the research notebooks and data.
The substantive purpose of the data was relevant to some aspects
of the organization of the I-1 notebook which the Secret Service
considered outside the norm. For example, the use of an
unusually large number of cut strips and small segments of tape
(and some dating problems) may result from a frequent need to
directly compare results of several large assays which could not
have been performed in a short time and for which the samples
could not easily be lined up without much cutting or hand
transcribing of numbers. Thus, the overall assessments of the
examiners about the oddity of the I-1 notebook is of more limited
utility.
The detachment of the Secret Service analysis from scientific
context affected the weight to be given their conclusions in
another way, as well. Many of the conclusions in the Secret
Service reports are couched in terms of whether certain pages or
data are "consistent with" or "most consistent with" having been
produced on particular dates. See, e.g., Exs. H501, at 2, Ex.
H502, at 3. The phrase "consistent with" is defined to apply
when "a definite determination is not justified because of a lack
of individuality, but the evidence points toward an event as
having happened with no evidence to the contrary." ORI
Report 191, n.150. The phrase "most consistent with" is defined
to apply when "more than two events are possible, but one is more
likely than any of the others." Id. The Secret Service
examiners lacked any information about evidence other than their
own forensic findings that was contrary to the conclusions they
reached or that showed that they were wrong about the relative
likelihood about two different events. Therefore, their
conclusions failed to take account of the larger picture.
Evidence presented on the existence or absence of matches
between certain counter tapes in the I-1 notebook and those
in other researchers' notebooks is of limited probative
value.
First, we emphasize that the document examination tests do not
raise any suggestion that the counter tapes in the I-1 notebook
were not genuine counter tapes produced by machines of the sort
available at MIT throughout the period and regularly used by
Dr. Imanishi-Kari and her laboratory. Instead, the questions
raised were as to whether they were likely to have been produced
at the particular dates indicated on the pages in the I-1
notebook where presently located.
In that regard, several aspects of the tapes were given
significance. The greatest attention was directed at green tapes
on pages dated in 1985 in the I-1 notebook. The tapes which the
examiners called "green" were distinguished by eye from the other
tapes which were mostly yellower in color, but the shading
difference between "green" and "yellow" was subtle and there were
variations in precise color. The examiners concluded that these
tapes were not produced at the "purported" time period because
(1) no notebooks other than I-1 had green counter tapes with
dates later than January 1984; (2) Dr. Imanishi-Kari's green
tapes matched tapes from much earlier time periods thought to be
produced on the same printers (in ink formula and the intensity
of the printing); and (3) Dr. Imanishi-Kari's green tapes did not
match other tapes from the purported time period. See Exs. H502,
at 3, H503; ORI Br. 89. We discuss next why each of those
findings had limited probative value. 52/
Even if no other notebooks now contain green tapes dated
after 1984, such tapes may still have been generated in 1985
and not be in the record before us.
After careful review we find that no clear dividing line has been
established to support an inference that no green tape could have
been produced in 1985. In order to derive such an inference from
the absence of such tapes in other researchers' notebooks after
January 1984, it would be essential to find that a virtually
complete set of the counter tapes generated in 1985 had been
examined. 53/ Here, on the contrary, as explained above, we have
no indication that laboratory notebooks examined represented the
majority (much less a complete set) of notebooks generated by
researchers in the laboratory at the relevant time. Even if
these were most of the notebooks, we have no indication that most
counter tapes generated at the time were ever retained or placed
into notebooks. 54/ MIT Provost Deutch informed OSI that
"individuals enter the results from gamma counter measurements in
their laboratory notebooks in different ways including cutting or
recopying tapes and it is unlikely that a complete record for any
instrument can be obtained." Ex. H278, at 5. We know from
examining extant notebooks that many researchers tended not to
preserve original tape data at all, but merely wrote down their
results (in particular, Dr. O'Toole). ORI itself noted "the
apparent practice of many researchers to destroy tapes when
finished with them." ORI Reply Br. 13. Nevertheless, ORI argued
in effect that "a fairly large sample of green tapes [is]
available." Id. A sample, even if it were fairly large, would
not suffice to eliminate the possibility that matching green
tapes were produced in 1985 in relatively small quantities and
hence were not among those that happened to be preserved by
anyone other than Dr. Imanishi-Kari. 55/ ORI asked us to
conclude that green tapes were no longer used in the laboratory
in 1985 based in part on information obtained by the Secret
Service around 1989 from a source for the tapes (Western Union)
to the effect that they stopped seeing greenish tinted tapes
"around 1983 and 1984." Tr. 3738-39 (Stewart). 56/ While ORI
concluded that this information was consistent with the green
tapes being phased out in 1983 and therefore unavailable in the
laboratory by 1985, it is equally consistent with the tapes being
available for purchase at least through 1984 and thereafter being
gradually used up by customers like MIT from their stocks. 57/
Such a pattern would also equally well accord with the undisputed
observation of the notebooks in the record, which show relatively
frequent use of green tape in 1981 through early 1983, followed
by sporadic appearances thereafter, ending in mid-1985. ORI
Reply Br. 13; R. Br. 30. 58/
We cannot even be certain that none of the other green tapes that
are in the record were from 1985. Undated green tapes appear in
two Maplethorpe "notebooks" (C-2 and C-5) which could be from
after January 1984. The C-5 notebook, which contains one of the
loose undated green counter tapes, has pages dated from 1984-85.
ORI argued that there is some evidence that these tapes are not
from 1985 because they were paper-clipped to other tapes dated
from February 1982-January 1984. ORI Reply Br. 13. However, we
do not know whether the paper clips were put on by Dr.
Maplethorpe or by someone else in the investigative process, and,
in any case, the grouping of tapes from three different years
together is hardly proof that an undated tape in the same
grouping could not be from a later date. 59/
We therefore decline to infer that green counter tapes dated
after January 1984 are necessarily misdated. We turn next to the
significance of finding full matches in earlier time frames for
particular green counter tapes.
The existence of "matching" tapes from 1981-1984 does not
prove that green tapes in the I-1 notebook were not produced
in 1985.
A "full" match in this context meant two green counter tapes with
matching printer type font and matching ribbon ink (formula and
intensity). There were difficulties with both the printer and
the ribbon aspects of a "match." Unless it were conclusively
established that two counter tapes were produced by the same
printer, it would be irrelevant whether they were produced by
ribbons using the same formula of ink or at the same point in the
cycle of intensity. We therefore consider whether the Secret
Service investigation was able to establish whether two counter
tapes were produced by the same printer.
The investigation of the counters and printers used by MIT
researchers at the relevant time period (roughly 1981-1986)
depended largely on information provided by MIT (indicating that
six counters were on site during some part of that period) and a
visit to view the location of those that were still in operation
in 1989. Ex. H278; Tr. 3726-3734 (Stewart). Of the six in use
at the relevant time, it is not disputed that three were on the
first floor, where Dr. Imanishi-Kari's laboratory (among others)
was located in 1984-1985: a Beckman gamma counter, a Packard
gamma counter and a Packard beta counter. Each counter came with
a printer with which each counter was normally associated
thereafter. 60/ Tr. 4571-72 (Igras). The printers involved here
were teletype-style impact printers using ribbons like those in
old typewriters.
The counter tapes produced by different machines could be
distinguished by several characteristics, some of which were
attributable to the counter itself and some of which were
attributable to the printer being used. See Ex. R67; Tr. 4246-53
(Richards), 4586-98 (Igras). The counter determined the format
of the information on the tape. Id. For example, only the
Beckman gamma counter periodically inserted a register number on
the tapes which it produced, and its formatting produced
printouts with two-place decimal points and double line spacing
between counts. Tr. 4585-86, 4593-96 (Igras); Ex. R67. The
Packard gamma counter format was single-spaced with no decimal
points. 61/ The Packard beta counter format was also single-spaced
with no decimal points. Tr. 4586 (Igras); Ex. R67. The teletype
printers functioned as "dumb terminals" in regard to the
formatting of the printout. ORI FFCL IV.D.9 and cites therein.
The teletype printers were all the same model but they differed
in the "font" of the letters and numbers which they produced
(which was determined by the printer not by the information sent
to it by the counter to which it was connected). Tr. 4028
(Stewart), 4251-54, 4438 (Richards), 4571, 4586, 4593 (Igras).
The printers normally associated with the Beckman gamma and
Packard beta counters had fonts that were "virtually identical."
ORI FFCL IV.D.7, and cites therein. It is thus clear that the
same font can be found on more than one printer. The printer
normally associated with the Packard gamma counter had a
different font, most easily distinguished by a slash through the
zero which does not appear in tapes produced by the other
printers identified here. Tr. 4597-98 (Igras), 3731 (Stewart);
Ex. R67.
Since there are tapes in the I-1 notebook exhibiting the font
characteristics of both kinds of printers, the examiners could
safely conclude that at least two different printers were used to
generate tapes in the I-1 notebook. See Tr. 3727 (Stewart). In
addition, there were tapes exhibiting the format characteristics
of both of the gamma counters from the first floor laboratory
(along with the font characteristics of the printers usually
associated with those counters). Since Dr. Imanishi-Kari agreed
that she predominantly used the two gamma counters on her floor
in conducting the research contained in the I-1 notebook, it was
reasonable to infer that the source of each of those tapes could
be traced to the counter with the matching format and either the
usual printer or one with same font attached to that counter.
Cf. Tr. 5097-98 (Imanishi-Kari). However, this evidence does not
establish either that all of those tapes were generated with only
two printers or that all of the tapes in the notebooks of other
researchers with matching format or font characteristics were
generated on the same counters or printers used in the I-1
notebook. 62/ See, e.g., Tr. 4552-53, 4557-58 (Verret) (if a
printer hooked to a counter broke down he would use a counter in
another department at MIT, most often in another building).
ORI disputed the possibility that matching tapes with identical
fonts could represent different printers as a result of switching
printers between counters or substituting back-up printers with
matching fonts during downtime. First, ORI relied on testimony
of Ms. Igras for the proposition that printer substitution
occurred only once while she was at MIT. ORI Br. 91. However,
it is clear in context that she testified more narrowly that she
was aware of only one complete replacement of a printer that
could not be repaired on site. Tr. 4623-24. She did not testify
that temporary or short-term use of a back-up during the much
more usual in-house printer repairs did not occur at other times.
63/ Mr. DeHaro (the building manager at the Cancer Center for 22
years) testified that such temporary changes did occur. 64/
Second, ORI's claims that printer breakdown was "a fairly rare
event" and "printer substitution even rarer" misstates the
record. ORI Br. 91. Ms. Igras did not testify that printers
broke down only two to four times a year, but rather that was how
often "you would get probably . . . outside service calls." Tr.
4573. On other occasions, the problems could be repaired in-
house. Id. Mr. DeHaro testified that he switched printers as
needed. Tr. 4448, 4469. He testified that printers broke
"pretty frequently" and that "three, four . . . times a year" he
would plug in another one that did work without keeping any
record of such substitutions. Tr. 4451. Further, Mr. Stewart
testified that he was told by Beckman representatives that it was
very easy to move printers between counters and that the printer
"broke down a lot" and "had to be repaired quite often." Tr.
3914-15. In addition, Mr. Stewart testified that he knew from
"talking to them at MIT that many times they made multiple calls
on repairing instruments, and that's why they had a stash of
extra machines to use in case these machines went down." Tr.
4103. ORI's position is also undercut by ORI's own argument that
printers were easily switched between counters without any
formality or record. 65/ In light of the testimony that printer
repairs and substitutions did not necessarily involve requests
for outside service or any formal recordkeeping, we find that the
service records for the counters and printers provided by MIT
represent only a part of the repair history, at least for the
printers which were "primitive machines" that could be worked on
by the users. Tr. 4573 (Igras). In addition, MIT indicated that
the service records were only those available as of fall 1989 and
MIT did not represent that they constituted a complete record.
Ex. H278.
Even assuming all of the I-1 notebooks tapes were generated by
the two counters on the first floor and that those counters were
using their normal printers to produce all those tapes, ORI did
not establish that counter tapes found in the comparison
notebooks were necessarily produced on the same machines, even if
the format and font on tapes were the same. MIT Provost Deutch
warned that, "in order to make an accurate association between a
specific tape and a specific machine, the individual student or
postdoc would have to remember which instrument was used for a
particular run." Ex. H278, at 5. 66/ There is no indication of
any researcher who was able to inform ORI or the Secret Service
of which counter and printer was used to produce a particular
tape. No log books were kept of the usage of the counters and
printers. Id. at 5. Rather, the examiners extrapolated from
matching formats or fonts that the source machines must have been
the same.
ORI argued that even if two different printers were used that had
the same font, the conclusion that the I-1 tapes matched much
older tapes "does not depend on the font in isolation, but rather
on the concurrence of several variables, including paper and
ink." ORI Br. 70. We discuss the findings on ink next ("paper"
means only that the tapes all showed the green tint), but it is
plain that the Secret Service findings connecting the I-1 green
tapes to earlier dates depended on their having been produced on
the same printer -- the use of the same formula of ink in a
ribbon used on another printer at a another time is meaningless.
In fact, ORI recognized that the findings of "full match" mean
little and in post-hearing briefing put most weight on the
absence of matching tapes in other notebooks from the particular
time periods during which Dr. Imanishi-Kari's green tapes were
purportedly generated. Thus, ORI argued regarding one set of
green tapes, as follows:
We note, as an initial matter, that the match itself is not
particularly critical: the critical fact is that the 1985
green tapes do not match other 1985 tapes from the same
counter that were generated in the same time period as the
June subcloning tapes. This fact alone provides substantial
evidence of fabrication and falsification.
ORI Br. at 69. We therefore turn next to the findings that
particular tapes from similar time frames do not match in printer
ribbon ink or intensity.
ORI did not prove that the absence of "contemporaneous
matches" to certain questioned Dr. Imanishi-Kari green tapes
implies that the questioned tapes were falsified as to date.
The Secret Service examiners tested yellow counter tapes with the
same format in another notebook dated in a narrow time frame
around the contested green tapes to determine if those that
appeared to have been generated by the same counter as the
contested green tapes had the same ink formula and similar
intensity of ink. Based on not finding matches in this effort,
the examiners concluded that the questioned tapes were not
authentic as to date. This conclusion depended on the tapes
being compared having been produced on the same counter and
printer, since it would be meaningless to merely show that other
counters or printers in use at the same time produced tapes that
were different from Dr. Imanishi-Kari's. However, the examiners
were not able to establish this predicate.
First, two tapes with the same format could be assumed to come
from the same counter only if they were both generated in the
first floor laboratory of the Cancer Center. While
Dr. Imanishi-Kari testified that she used the first floor
counters predominantly in the work contained in the I-1 notebook,
we have no assurance that tapes in other notebooks were generated
on first floor counters. Therefore, the occurrence of the same
format on a tape in another notebook as that on a tape in I-1 is
not a guarantee that the two tapes were produced on the same
counter.
Further, even assuming the matching formats implied that the same
counter was used for both tapes, this would not establish that
they were produced on the same printer. As discussed above,
printer fonts were not unique and substitution was not unusual.
In addition, all the difficulties discussed in regard to
assessing the significance of not finding green tapes after
January 1984 also apply to assessing the significance of not
finding contemporaneous tapes from particular dates that match in
tape color or ribbon ink. Matching tapes may have existed that
were not preserved or not included in this record. Without
confidence that the record would include any matching tapes if
some were generated during the same time frame, we cannot
reasonably infer from the Secret Service findings that the
challenged tapes were not generated at the time represented.
The mere use of yellow counter tape on dates close to those on
which Dr. Imanishi-Kari's green tapes were purportedly generated
is meaningless. The testimony established that the counter tape
paper rolls could be changed at any time by almost any one.
There was uncontradicted testimony that partial rolls were
sometimes removed before a long assay to ensure that paper would
not run out and then the leftover old rolls were used at later
date. Tr. 5101 (Imanishi-Kari). Therefore, the appearance of
one color roll of tape on a certain printer would not necessarily
mean that it would be reasonable to expect that printer to
continue to generate tape of that color for the length of an
entire roll.
In relation to the ink formula tests, Mr. Stewart testified that
the Secret Service attempted unsuccessfully to pinpoint the
dating of the ink used on the printer ribbons. Tr. 4010. 67/ In
addition, the tests used by the Secret Service were not able to
identify whether print was produced by the same ribbon, but only
whether the ribbons used contained the same formula of ink which
might have been used on hundreds of thousands of ribbons. Tr.
4109-10 (Stewart). 68/ The tests could establish if ink samples
taken from two ribbons did not contain the same formula of ink,
and it was clear that at least two formulas of ink were used in
ribbons to produce the tested counter tapes. 69/ See Tr. 3759-61
(Stewart). It was likely that MIT purchased the ribbons in large
quantities which might all have contained matching ink formulas
or might not have. Tr. 4108-09 (Stewart). There was no evidence
that MIT researchers used up each batch of ribbons before using
ribbons from another shipment (which might have supported an
assumption that matching ink formula indicated a similar time
frame if the formula in each batch or even each ribbon were
always the same, which was not demonstrated). Tr. 4109
(Stewart). The dry ribbons could be stored and used after many
years. Tr. 4111 (Stewart). ORI did not establish that tapes
from surrounding dates matched green tapes in the White-Scharf
and Maplethorpe notebooks. Exs. H30, H31, H75. 70/ Thus, no
inference may reasonably be drawn from the observation that tapes
from different time frames had matching ink formulas or that
tapes from similar time frames had different ink formulas.
In relation to ink intensity, the Secret Service examiners
observed that in general the trend was that the intensity of ink
color over consecutively dated tapes showed a gradual decline in
intensity as the ribbon wore out and then a sharp change to dark
intensity as it was replaced with a cycle of about 90 days. Tr.
3646-48, 3715-16, 4004 (Stewart). Mr. Stewart also noted that
ribbons that were worn might be reversed or raised laterally to
reach a clean area, rather than replaced, but assumed that this
would not affect the continuity of ink intensity, since it would
represent an abrupt return to very dark followed by a gradual
lightening, just as with a replacement. Tr. 3735-36. However,
Ms. Igras testified to another possible response to fading ink
intensity. She stated that sometimes "instead of replacing it,
people would rewind it" in order to "get their printout." Tr.
4580. The examiners did not indicate that they tested for the
possibility that such rewinding would result in print that was
more legible than print from the end of a ribbon but not dark as
a clean section would be. There was testimony that ribbons were
easily changed and sometimes switched between printers (which
would result in an abrupt change in intensity of the output of a
printer without a return to a "new" dark stage). Tr. 5102-03
(Imanishi-Kari). Some inference might be drawn from a break in
the cycle of ink intensity if it were established that tapes came
from the same printer while using the same ribbon. Since ORI did
not establish those prerequisites, inferences drawn from ink
intensity observations would be unreliable.
For the reasons explained above, we conclude that the fact that
tapes dated around the same time as Dr. Imanishi-Kari's green
tapes do not match her tapes in color or ink formula or intensity
fails to establish that her green tapes are not authentic as to
date. 71/
The Secret Service conclusions that several tests
collectively establish that certain pages in the I-1
notebook were compiled out of order in 1986 (rather than
1984 as "purported") are not adequately supported by the
evidence in the record as a whole.
The Secret Service relied on several tests to suggest that pages
in the notebooks dated several years apart were actually created
around the same time. Particularly disturbing was the argument
that these pages were created in 1986, after the Cell paper had
been published. However, the significance of these findings is
greatly diminished by our conclusion that Dr. Imanishi-Kari never
asserted that the pages in the I-1 notebook were created in 1984.
All these tests go to creation of pages not the creation of data,
and, as explained above, Dr. Imanishi-Kari never denied that she
organized data at different times than she generated them,
possibly as late as 1986.
Furthermore, ORI injected a false sense of precision to its
claims about the dates on which these pages were created by
misstating what the tests employed by the Secret Service can
show. For example, ORI discounted scenarios other than
fabrication on the grounds that they would involve
Dr. Imanishi-Kari having used the same pad and pens two years
apart. ORI Br. 46. However, the Secret Service considered only
whether pages from the I-1 notebook were created using the same
kind of pad paper and same formulas of ballpoint ink as pages
from the I-3 notebook (also belonging to Dr. Imanishi-Kari) which
dated from 1986. In addition, the Secret Service looked at
impressions (made visible by a mechanism known as an
Electrostatic Detection Apparatus or ESDA) from the writing of
one page appearing on other pages which were hence presumably
underneath at the time of the writing. The document examiners
themselves agreed that none of these tests proves anything
significant independently, although collectively they contended
they were meaningful. We consider next the limits of each of the
tests used, in weighing the conclusions which ORI would have us
draw from their results.
In regard to the paper used in the I-1 and I-3 notebooks, the
examiners studied the thickness and other characteristics of the
paper which was removed from pads of the kind glued at the top
(this analysis did not involve looseleaf or spiral notebook paper
which was also used for some pages in the I-1 notebook) and
certain identifiable, "reproducible" defects that occurred in
printing of the pads. Tr. 3683-87, 3693-95 (Stewart). By these
means, they determined that the pad paper in the I-1 and I-3
notebooks came from at least two different sources, based on
differences in thickness of paper and in specific defects.
However, the examiners testified that paper with a particular set
of defects could run through entire batches of pads. Also, the
evidence on the printing process for these pads showed that a
defect could occur on all or only some pages in a particular pad
depending on the cause of the defect and the practices of the
printer in interleaving pages to form pads. Tr. 3688, 3966-69
(Stewart). So again (at best) we can infer that some pages did
not come from same pad but cannot say if pages did come from same
pad, only that they could have. 72/ Mr. Stewart himself
testified that in his own practice he sometimes used only a few
pages from a pad or used old pads with "cobwebs" so that he had
to look for some other forensic basis to tie together any
significance in the use of the different pads within a short time
or the recurrence of the matching pad paper in different years.
Tr. 3676, 3699-3700. He characterized the pad paper analysis "in
and of itself" as "marginally significant," but pointed to the
other findings described here as providing a weight of forensic
evidence to which the pad paper defect analysis contributed. Tr.
3928-30.
The examiners also analyzed the ballpoint pen ink used to make
notations on various pages, but they were not able to identify
particular pens used or to determine that ink used was not
available at a purported time. No evidence was provided that any
ink formula found or pens containing any of the formulas found
were unavailable at any point during the relevant period. That
is, like the analyses of ribbon inks, these analyses did not
preclude production of the pages on the dates written on them.
73/ Again, the analysis permitted the examiners to say with some
certainty that two samples of writing were not done with the same
pen, but not to say if two matching samples were done with the
same pen, only that they could have been. Nothing suggests that
any of the ink formulations identified were in the least
uncommon. In fact, ORI did not dispute that pens (like the pads
of paper) were probably bought in bulk. ORI Br. 46-47. Common
experience suggests nothing unlikely about an office or
laboratory having lots of one or two sorts of ballpoint pens or
leftover pads from one or two shipments available over a two-year
period. Again, Mr. Stewart acknowledged that the use of pens
with the same ink formulas on pages from different years was not
remarkable "on the surface." Tr. 4188. Further, when asked if
the use of the same kind of paper and ink on documents dated two
years apart meant that one or both were fabricated, Mr. Stewart
testified that it did not. Tr. 3928.
Turning to the ESDA impression analyses, it is important to
recognize that this approach addressed only the order in which
pages may have been written and did not purport to identify time
frame in which any page was written. Furthermore, the ESDA
analyses did not purport to say anything about when the
underlying data on the counter tapes (as opposed to the notations
on the pages) were created.
The examiners differentiated between impressions which appeared
askew on the page below and those impressions that were "in
registration." "Registration" was defined as a situation where
the impressions are aligned when the edges of the two pages are
lined up. Impressions that were askew were interpreted only to
mean that the page being written on happened to be on top of the
page receiving the impressions at the moment that the notations
which appeared on the ESDA were made. The examiners inferred
that finding an impression in registration in the I-1 notebook
meant that the page being written was still attached to a pad
above the page receiving the impression and was written prior to
the page below. ORI Report 191, n.150. Based on this inference,
the examiners concluded that, for example, when impressions in
registration of a page bearing a date in 1986 appeared on a page
dated in 1984, this was evidence that the "purportedly" 1986 page
was actually created first. See, e.g., ORI Report 194. This is
possible, but other possibilities also existed. The Secret
Service witnesses acknowledged that stacking pages that were
already detached from a pad could cause impressions to appear in
registration. Tr. 3466-67 (Hargett). However, they rejected
this possibility for most examples of registration found in the
I-1 notebook on the grounds that many other impressions were
skewed, which meant that Dr. Imanishi-Kari did not always stack
her pages neatly, and that they did not find marks of staples or
paper clips. Tr. 3539-40 (Hargett), 5568 (Stewart). Thus, Mr.
Hargett testified that that was "our logic . . . be it right or
wrong . . . was that it was on a pad, and not straightening of
the papers." Tr. 3540. This logic is obviously flawed, since
one can straighten pages on some occasions without doing so
constantly and one certainly need not staple pages in order to
stack them briefly while writing. 74/ The ESDA process does not
distinguish whether the page receiving the impression already
contained writing. Thus, folding a blank page on a pad back over
a page lower in the pad which was already written on would create
an impression in registration even though the page below was
actually written first (but not yet removed from the pad). Cf.
Tr. 3258-61 (Hargett). Since Dr. Imanishi-Kari testified without
contradiction that she often compared assays from different time
periods in organizing her data, it is possible that impressions
of later notations would appear on pages that were already
written or that pages with earlier data might be compiled and
written on at the same time as a much later assay was being
recorded. We therefore cannot conclude from ESDA results alone
that a particular page was fabricated because it contained an
impression in registration of a page reporting data from a later
experiment. 75/ Mr. Hargett, when asked how much reliance he
placed on the ESDA results, acknowledged that if that analysis
were "by itself, standing alone, . . . we wouldn't be here
today." Tr. 3499. Each of the other analyses which the
examiners relied on in combination with the ESDA results suffered
from limitations and weaknesses which similarly undercut them,
however.
It is also important to consider, in seeking overall conclusions
about the document examination evidence, whether
Dr. Imanishi-Kari had any conceivable motive for the allegedly
false dating of the questioned pages. While some of the pages
involved contained relevant data (in particular, I-1:41 and I-
1:113, which were shown to Dr. O'Toole at a meeting), 76/ ORI
offered no possible reason to fabricate other pages for which the
same findings were presented.
The Panel concludes that, in reaching their opinions, the
examiners and ORI were misled by mistaken assumptions about what
the documents they were reviewing "purported" to be, failed to
establish a meaningful comparative norm, failed to put the
documents which they were reviewing into a realistic scientific
context, and overlooked the impact of the limitations of the
examination results in supporting their conclusions. As a
result, the inferences ORI drew from the document examination
results were not reasonably supported. Therefore, we conclude
that ORI failed to prove that the document examination findings
in themselves demonstrate that it is more likely than not that
the conditions found in the documents were the product of
deliberate and intentional fabrication or falsification.
V. DISCUSSION OF CHARGES
A. Figure I
1. BET-1 Specificity
Figure 1, charge one: ORI charged that Dr. Imanishi-Kari's
"failure to disclose significantly discrepant results in the
experimental record concerning the specificity of BET-1 . . . was
a deliberate misrepresentation of scientific results constituting
a falsification of data and scientific misconduct." Charge
letter 2-3.
Issue: Figure 1 of the Cell paper compares the sera of
transgenic and normal (C57BL/6) mice. In each assay reported, a
coating of anti-idiotype reagent was used to capture idiotype-
positive antibodies and then two reagents were used to test for
variants or allotypes of IgM antibodies. 77/ C57BL/6 mice
normally produce IgM antibodies of the allotype æb (hence
considered endogenous). By contrast, the BALB/c mice from which
the transgene was derived produce IgM antibodies of the allotype
æa. The researchers were interested in testing for allotype in
the idiotype-positive antibodies produced by the transgenic mice.
They used two anti-allotype reagents, both monoclonal antibodies:
AF6 to identify the endogenous æb allotype and BET-1 to identify
the transgenic æa allotype. In addition to data showing the
pattern of reaction of the normal and transgenic sera to AF6 (top
panel of the figure) and BET-1 (bottom panel), the figure
included data showing how each reagent reacted to control
hybridoma proteins which represented standards for C57BL/6 mice
(P9.37.9, æb) and BALB/c mice (20.1.21, æa). Both P9.37.9 and
20.1.21 were NIP-positive and anti-17.2.25 idiotype-positive by
other tests. Normal C57BL/6 and BALB/c sera were also used as
controls. The tests of the reagents against the control proteins
served to establish the effectiveness of the reagents for
distinguishing the two allotypes. Charge one attacked the data
in the bottom panel which showed that BET-1 did not react
significantly with the æb control protein (or the normal sera)
but reacted strongly with the æa control protein (and the
transgenic sera). ORI alleged that results in the notebooks from
other experiments which used BET-1 showed much less specificity.
In addition, ORI alleged that the following statement in the text
of the Cell paper was inaccurate for the same reason:
The BALB/c anti-NP IgM antibody, 20.1.21, bound only to the
anti-æa allotype reagent, as it should, and the C57BL/6
anti-NP IbM antibody, P9.37.9, bound only to the anti-æb
allotype (Figure 1).
Cell paper 249 (emphasis added).
Analysis: Figure 1 and the accompanying text report results of
specific experiments which used BET-1 as one of the reagents, not
a survey of results using BET-1. To the extent that the actual
behavior of the control proteins with BET-1 was represented
correctly, it is not clear that it is fair to characterize them
as misleading even if there are some contrary results in other
experiments. ORI did not set out a charge asserting that the
data reported in Figure 1 were not authentic, but made
allegations to that effect in its proposed FFCLs. Therefore, we
deal in this section first with whether the Cell paper falsely
reported the specificity of BET-1 in the assays reported in
Figure 1. In the next section, we consider ORI's claim that
Dr. Imanishi-Kari was required to report other data that were
"representative" of the experimental record as a whole and
whether she deliberately failed to do so. ORI Br. 35-36.
All of the experiments presented in Figure 1 were performed by
Dr. Reis, who prepared the graphs of her results for publication.
Tr. 4691 (Imanishi-Kari), 2504 (Reis). The original graphs for
Figure 1, which form part of the raw data, are at R-1:65-68 (with
headings in Dr. Reis's handwriting). Unquestionably, Dr.
Imanishi Kari worked closely with Dr. Reis and reviewed her work.
Tr. 4906, 5462; Ex. H100, at 3. Dr. Imanishi-Kari did not deny
that she shared responsibility for Figure 1, but it must be
recognized that she relied on Dr. Reis as the original source of
the data.
Assuming that the data at R-1:37-40 and the graphs at R-1:65-68
are legitimate, as we conclude below, there can be little
question that Figure 1 is an accurate reflection of actual
experiments insofar as it represents how BET-1 performed in those
particular assays. The textual statement, however, if taken
literally in asserting that the control proteins "bound only" to
the respective allotype reagents, amounts almost to another
example of error obvious on the face of the paper; as Dr. Eisen
said, "antibodies don't bind only to something;" there is always
some cross-reactivity to other proteins. Tr. 2022; see also Tr.
2823-24 (Capra). Even Figure 1 itself could be considered to
conflict with this statement since AF6, and to a minor degree
BET-1, show some level of non-specific binding, whether through
stickiness or lack of specificity, as ORI itself noted. ORI Br.
37, n.20. Dr. Imanishi-Kari has long acknowledged that BET-1
does not perform with absolute specificity, but asserted that it
discriminated well enough between the two allotypes and performed
as reported in the Figure 1 assays. The text is most reasonably
read in conjunction with the figure to mean that the reagents
behaved as specifically as shown in the data (which quantify the
specificity obtained in those assays).
In evaluating this charge, it is essential to recognize that
BET-1 is not a standard off-the-shelf reagent. BET-1 is a rat
anti-æa monoclonal antibody produced by a hybridoma cell line.
Cell paper 257. Preparation of BET-1 required cloning of the
hybridoma and purification of supernatants in batches. In order
to use BET-1 as a probe, it was further necessary to label the
reagent with radioactive iodine (125I). The useability of each
batch was limited by radioactive decay. No records were kept to
identify or date the preparations of reagent or the specific
iodination of reagent used in a particular experiment. 78/
Therefore, some of the difficulties observed with data using
BET-1 may reflect variation in the batches of BET-1 rather than
failure of BET-1 to function as expected as a reagent. 79/
Figure 1 does not misrepresent experimental data.
As noted, nowhere in the charge letter is it expressly alleged
that the raw data supporting Figure 1 were fabricated. However,
in its presentation at the hearing and its proposed FFCLs, ORI
alleged that forensic findings concerning R-1:37-40 undercut the
validity of the data so that they do not constitute credible
support for Figure 1. Cf. ORI FFCL IX.C.i.1-11; see Tr.
1297-1301, 1311-12 (Davie). Since Dr. Imanishi-Kari did not
object that she lacked notice of this allegation, and her brief
discussed this data, we address the issue here. R. Br. 44.
The document examination findings are: that the 5/24/85 date on
R-1:37 was altered in a different ink than other entries on the
page; that the date on the AF6 portion of the protocols on the
preceding page (R-1:36) was changed from 5/9/85 and the BET-1
protocol was entered at a different time since it does not appear
on an ESDA of R-2:22, which contains an impression of R-1:36
(from R-2:22, Ex. H541); and that the counter tapes from the BET-
1 and AF6 data were generated weeks or months apart and not on or
about the same day, 5/24/85.
As discussed in the overview of the document examination issues,
we do not consider the 5/24/85 date to be a representation that
the entirety of both assays were completed within a few days of
that date. It would be entirely consistent with the practices
for dating experiments in Dr. Imanishi-Kari's laboratory for one
assay to have been performed around 5/24/85 and the other around
5/9/85 and the dates changed to the latter when the entire
experiment was complete. ORI suggested, instead, that the motive
for changing the date was to permit Dr. Imanishi-Kari to claim
falsely that the BET-1 used in Figure 1 was from a new cloning of
BET-1 producing cells described on I-1:121, dated 5/22/85, where
BET-1 was working well, but which ORI alleged was a fabrication.
According to ORI, the BET-1 actually available for the assays at
R-1:37-40 was the same batch used in assays reported at R-1:18,
dated 5/7/85, where the reagent failed to work specifically. As
discussed below in relation to charge two on Figure 1, we do not
find the evidence adduced to support the claimed fabrication of
I-1:121 to be persuasive. Furthermore, since we conclude that
there is experimental evidence throughout the notebooks that
BET-1 was capable of identifying the æa allotype with adequate
(but not absolute) specificity, we do not agree with ORI that
Dr. Imanishi-Kari had a motive to alter the dates to create an
appearance of having performed the assays after the experiment on
I-1:121.
This issue is complicated somewhat by confusion about precisely
which data represent the specific experiments reported as
Figure 1. The data at R-1:37-40 are in close accord with the
values on the graphs in Figure 1 (as Dr. Dahlberg himself
verified), except that the raw data for the fourth point for six
out of the eight curves shown in Figure 1 are missing. 80/ ORI
FFCL IX.C.i.7; see Dahlberg Decl., Att. 1. Dr. Reis indicated
that the missing dilution may have been completed on a different
day than the first three dilutions shown and simply were added
directly to the graphs to complete them. 81/ Tr. 2639. Dr.
Imanishi-Kari testified that the data now in the notebook are a
retest of the same sera which yielded virtually identical values
(at least as calculated by percentage of maximum binding for the
figure) but that the raw data for that assay are missing except
for the curves themselves. Tr. 5296, 5462-63. ORI did not
demonstrate that standards of conduct for scientists in
Dr. Imanishi-Kari's field at that time would have required
retention of the counter tapes or a record of the actual cpms,
where the quantitative results were preserved in the original
graphs in Dr. Reis's notebooks. ORI did not demonstrate that the
experiment could not have been performed as the witnesses for
Dr. Imanishi-Kari testified, with an additional dilution done
separately or as part of the retest. The data on R-1:37-40
(whether the data directly reported in Figure 1 or a retest
confirming the results on the same sera) constitute experimental
support for the accuracy of the quantitative results reported in
Figure 1.
Since we conclude that Figure 1 accurately reflected actual data,
we must next consider whether the figure and text nevertheless
misrepresent the experimental results because Dr. Imanishi-Kari
failed to disclose other experiments in which BET-1 was not
equally specific.
The results reported in Figure 1 and accompanying text were
not so discrepant that reporting them constituted a
misrepresentation of the experimental record. 82/
It is not disputed that the wording of the quoted statement in
the text overstates the degree of specificity with which BET-1
generally performs, in that the words "bound only" may imply
absolute specificity if read to refer to its general performance.
Dr. Imanishi-Kari did not dispute that sometimes BET-1 did not
work well as an allotype reagent, which she attributed to
iodination or other batch-specific problems or to "stickiness."
Dr. Imanishi-Kari said, however, she could discern these problems
in particular experiments from the controls and that she did not
use allotyping results from those experiments. It is not
disputed that BET-1 cross-reacted (i.e., gave erroneously
positive results) to some degree with the æb endogenous protein
even when BET-1 was "working."
This issue was directly covered by the NIH Scientific Panel
report which agreed that BET-1's specificity was not absolute and
required that a correction be published, but concluded that the
overstatement constituted error not scientific misconduct. 83/
The NIH Scientific Panel examined many BET-1 assays done by
different researchers in Dr. Imanishi-Kari's laboratory and found
that, while in some BET-1 failed to distinguish by allotype,
"most of the assays seen by the Panel clearly showed relative
specificity for æa." Ex. H262 (NIH Scientific Panel Report at
3). Those assays included one by Dr. O'Toole dated January 2,
1986 that showed 1,000-fold specificity and others of around 100-
fold specificity, all adequate to the purposes for which the Cell
authors used BET-1. Id. 84/ We agree with the NIH Scientific
Panel's assessment of the experimental record on BET-1
specificity because, as discussed below: (1) Dr. Imanishi-Kari
had no reason to lie about BET-1's specificity; (2)
Dr. Imanishi-Kari thought that BET-1 was adequately specific for
her purposes and was not attempting unsuccessfully to solve a
problem with BET-1 specificity in 1985; and (3) while the
implication that BET-1 was absolutely specific was erroneous, the
paper directed readers to the literature on BET-1 and was not
required to report all less successful results with the reagent.
It would not have been in Dr. Imanishi-Kari's interest to
overstate deliberately the specificity of BET-1 for æa.
Dr. Imanishi-Kari has long pointed out that she would have had no
motive to overstate the specificity of BET-1. If BET-1 failed to
discriminate well between transgenic and endogenous allotypes,
that would mean that endogenous antibodies were inaccurately
reported as transgenic. Since the central finding of the Cell
paper was the surprisingly high number of endogenous antibodies
bearing the idiotype, the authors had no reason to exaggerate the
level of exogenous antibodies. This position was forcefully
expressed by a former member of the NIH Scientific Panel who
wrote:
[F]alse positive Bet-1 is not really a problem, for the
scientific question at hand. It would be a great problem if
Bet-1 did give false negative results with Balb/c (i.e.
transgenic) æ. AF-6 (anti-æb, i.e. anti-endogenous æ) is
the more important anti-allotype reagent. It clearly
discriminates well. In fact, focusing so strongly on the
Bet-1 problem makes one wonder whether the rest of the
accusations may be false. Dr. Imanishi-Kari had no valid
scientific reason to falsify the Bet-1 data.
Ex. H299, at 3 (Dr. Storb); see also Tr. 2772 (Wortis).
Interestingly, even Dr. O'Toole testified that she agreed from
the beginning that problems with BET-1 in themselves would not
much undermine the paper. Tr. 972.
ORI disregarded this argument, saying that such a "harmless
error" defense is irrelevant if someone has acted intentionally
to falsify or fabricate data. ORI Br. 34. 85/ However, the
point here is that the complete absence of any motive makes it
less likely that any overstatement of BET-1 specificity was
intentional and less likely that any anomalies observed on the
pages containing BET-1 data are the result of intentional
fabrication in an effort to support such an overstatement.
Motive is not a required element of ORI's proof, as it would be
scientific misconduct to lie deliberately in published reports
even against one's own interest. The absence of any motive to
deceive is nevertheless relevant to assessing intent.
A review of the complete experimental record does not
support ORI's view that Dr. Imanishi-Kari deliberately
suppressed discrepant results.
ORI undertook an analysis of experiments in the R-1 and I-1
notebooks which it interpreted to mean that BET-1 "generally did
not discriminate well" between the æ allotypes. ORI Report 63-
66. The experiments reviewed were at R-1:18 (from the 17 pages),
R-1:34; R-1:37; I-1:110; I-1:111-12; I-1:113; I-1:115-8: I-1:119;
I-1:121; I-1:125A; and I-1:128A. Each of these pages showed an
experiment in which the control proteins were bound to wells and
then probed with iodinated BET-1, except for I-1:110 (which used
non-iodinated BET-1). ORI calculated the percentage of maximum
binding for the largest values in the dilution series for each
experiment as a measure of the degree of cross-reactivity. Based
on this approach, ORI reported high percentages (above 20%) of
binding to the æb protein for the following tests: R-1:18 (93%);
R-1:34 (24%); I-1:111 (46%); I-1:113 (55%); and I-1:115 (34%).
The other experiments showed at least some cross-reactivity: R-
1:37 (the retest of Figure 1 data was reported by ORI as 13%,
although using the same calculation as the other experiments
would yield 8%--ORI argued that the positive control value was
used as the maximum because it was lower than the highest
experimental value which ORI considered as suggesting the control
was done separately 86/); I-1:110 (17%); I-1:119 (6%); I-1:121
(11%); I-1:125A (12%); and I-1:128A (8%). 87/ See ORI Report 58.
Based on this analysis, ORI concluded that BET-1 cross-reacted
with the æb control protein in the majority of the assays. ORI
Report 66. However, the same figures support the opposite
conclusion, i.e., that most of the assays demonstrate adequate
specificity, if not quite as good as that in Figure 1. (ORI
estimated the percentage of cross-reactivity in the graph as
about 5%, although this number cannot be read by eye. ORI Report
66; ORI FFCL IX.A.8. 88/
The Panel notes that in his analyses in the ORI Report, Dr.
Dahlberg, may have engaged in data selection and interpretation,
not unlike that for which he criticized Dr. Imanishi-Kari, in his
presentation of notebook data on the specificity of BET-1. For
example, although he acknowledged on cross-examination that it
was more accurate to compare assays after subtracting the
backgrounds (and other scientific testimony was that this method
was the proper approach), he did not subtract backgrounds in
comparing assays from the notebooks. Tr. 535-36, 545-46
(Dahlberg), 1910 (Eisen). Dr. Eisen testified that the result
was to overstate the degree of cross-reactivity by BET-1. Tr.
1910. In the case of the assay on I-1:110, for example,
subtracting the background counts would halve the cross-reaction
to a level in line with Figure 1 (from 17% to about 9%). Tr.
535-36 (Dahlberg). In addition, Dr. Eisen testified that the
percentage of maximum binding on which Dr. Dahlberg relied to
assess non-specific binding by BET-1 is not the only or even the
best way to measure cross-reactivity, nor is it clear that the
highest dilutions give the most significant information. Tr.
1903-17 (Eisen), 538 (Dahlberg). 89/ Dr. Dahlberg's approach
focused entirely on the degree to which BET-1 cross-reacted with
æb at high concentrations, but, as the authors reported in the
correction letter, even in those experiments where there was
cross-reaction, much higher concentrations of æb were required to
elicit the same level of reaction. For example, in two assays in
O-1, which ORI cited as showing very high levels of cross-
reactivity because at the highest concentrations BET-1 bound with
æb at 62% (O-1:35) and 86% (O-1:36) respectively, the binding at
the next lower concentration with BET-1 drops to 28% and 44% with
æb while remaining at over 94% of maximum binding for æa. ORI
FFCL IX.B.3. In other words, BET-1 still discriminated heavily
in favor of æa.
ORI claimed that the data showing good specificity occurred on
forensically questioned pages, whereas the data showing little or
no specificity occurred on "undisputed pages." ORI Report 87.
While it is true that ORI attacked the authenticity of only the
pages showing good specificity, Dr. Imanishi-Kari pointed out
scientific problems in the assays reported on the pages on which
ORI relied that caused her to disregard them as valid measures of
BET-1's specificity.
The data for the experiment at R-1:18-24 (part of the 17 pages)
are clearly aberrant, in that BET-1 reacted almost as well to the
æb control as to the æa control (93%). ORI did not point to a
single other assay with comparable results, and such results are
inconsistent with the literature on BET-1 and the experience of
other researchers discussed elsewhere. The evidence from Dr.
Reis is that this assay was an anomaly in which not only did the
controls indicate a problem with the BET-1 but cross-
contamination of the supernatants tested was observed when the
plates were thawed. Tr. 2514-16. Consequently, the assay was
run anyway "only to have an idea," but the results were
disregarded as unreliable. Tr. 2517.
The counter tape on page I-1:112 contains a handwritten notation
by Dr. Imanishi-Kari saying "Bad label BET-1!" which is an
apparent reference to problems with the iodination of that batch
of BET-1. See also I-1:113-14. The experiment at I-1:111 had a
very high background and subtracting it entirely eliminated the
evidence of cross-reaction, suggesting that the problem here was
stickiness of the reagent rather than cross-specificity to æb.
The experiment at R-1:34 had so high a background that Dr.
Dahlberg thought it inappropriate to subtract the background,
because it indicated something went wrong in the experiment
itself, but he nevertheless relied on the cross-reaction data
from that experiment, rather than disregarding the experiment.
Tr. 133-34, 537.
In addition, ORI's analysis ignored other examples in the
experimental record which supported the reported results as
within the range of those obtained in the laboratory using BET-1,
including some of those obtained by Dr. O'Toole. 90/ For
example, Dr. Dahlberg later acknowledged that O-1:22 and O-1:133
represent tests in which BET-1 showed specificity against the
control protein. Dahlberg Decl. 6, Att. 6. Dr. O'Toole agreed
that BET-1 clearly recognized æa better than æb in her competition
assay at O-1:174, and in fact that BET-1 was useful as a specific
reagent in competition assays. Tr. 897.
Dr. Dahlberg also acknowledged that BET-1 was acting with good
specificity on R-2:46 if it was being tested against the control
protein but contended that this assay could be disregarded
because he believed that the controls were performed with sera
rather than purified proteins. Dahlberg Decl. 5; ORI Br. 28. 91/
He pointed out that the control data referred to the strains of
mice (BALB/c and C57BL/6) rather than naming the control proteins
(20.1.21 and P9.37.9). However, Dr. Reis testified that R-2:46
was actually performed using control proteins. Tr. 2652-54. She
explained credibly that in her early days at the laboratory, when
she was still learning the names and sources of the various
reagents, she sometimes found it easier to remember which control
protein came from which strain by recording the source strain.
Tr. 2656-58. 92/
Furthermore, Dr. Reis testified that BET-1 generally performed as
a "good reagent" for her. Tr. 2655. While she agreed that it
was not working in the assay at R-1:18, she testified that the
lack of specificity in that instance was the result of
contamination. Tr. 2515, 2630. Dr. Imanishi-Kari testified that
she told Dr. Wortis and the others that the only experiment she
remembered where BET-1 failed to show any distinction between æa
and æb was the one in the 17 pages, i.e., R-1:18. Tr. 4966.
The testimony of Dr. Wortis supported the testimony of
Dr. Imanishi-Kari and Dr. Reis about the performance of BET-1 in
the laboratory. He testified that his experience with BET-1 in
his own work was that it discriminated between æa and æb, but that
there were sometimes certain "batches that did not discriminate
adequately for my purposes." Tr. 2784. In those instances, he
handled the problem just as Dr. Imanishi-Kari indicated that she
had, i.e., he did not use experiments in which the controls
showed BET-1 not working adequately, but he did not discuss those
difficulties in published reports of his work since he was not
writing about BET-1 but only using it as a reagent. Id.
Similarly, Dr. Kearney (an expert immunologist with considerable
idiotype experience) testified that BET-1 was allotype specific
when used on ELISAs, which test protein molecules. Tr. 2446.
Dr. Capra testified that, while the literature makes clear that
BET-1's specificity is not absolute, it also clearly
discriminates significantly, which is "as good as it gets" for
this kind of reagent. Tr. 2824.
ORI did not prove that BET-1's relative specificity was a
serious problem or focus of concern for Dr. Imanishi-Kari in
1985.
Dr. O'Toole's claims that the poor specificity of BET-1 was a
major problem on which Dr. Reis and Dr. Imanishi-Kari were
working are not persuasive. Cf. Tr. 905-06 (O'Toole). One of
the early concerns raised by Dr. O'Toole after copying the 17
pages from Dr. Reis' notebook was that BET-1 completely failed to
discriminate between æa and æb in the assay at R-1:18. She
testified that she was not surprised by this because that was in
accord with her experience at the time of that assay (May 1985).
Tr. 913. Before she copied the 17 pages, Dr. O'Toole had
commented on a draft of the paper. Tr. 914-15 (O'Toole). That
draft contained essentially the same statement that BET-1 bound
only to the proper control protein. Ex. H227, at 8-9. It is not
plausible that, if Dr. O'Toole believed at the time of reviewing
the draft or galleys of the Cell paper that Bet-1 did not react
specifically and she had been complaining frequently to Dr. Reis
and Dr. Imanishi-Kari about it, she would fail to react to the
statement in the draft, if not to Figure 1 itself. Yet we find
no evidence that Dr. O'Toole tried to correct this statement in
the draft or made any notation about it.
Dr. Reis and Dr. Imanishi-Kari both deny that Dr. O'Toole
constantly complained to them about BET-1's specificity or
indicated that it never worked for her, as Dr. O'Toole said she
had. Tr. 4953-55 (Imanishi-Kari); 2512 (Reis); 898, 1064
(O'Toole). Dr. O'Toole's testimony made clear that her
particular experiments depended far more on the precise degree of
specificity than did those published in the Cell paper (because
she had to be able to distinguish carefully between a positive
reaction caused by a small amount of æa as opposed to a large
amount of æb). Tr. 893. However, BET-1 was known to be least
effective in cell staining experiments, in which Dr. O'Toole
apparently was engaged. Tr. 2438 (Swain), 2453-56 (Kearney).
She may well, then, have had some frustrations with BET-1 to
which the other researchers, who found it adequate for their
purposes, were not attentive.
ORI argued, however, that Dr. Imanishi-Kari not only knew that
BET-1 was unable to discriminate between æa and æb with the degree
of specificity reported in Figure 1, but that she "lamented" this
problem openly, sought with Dr. Reis to reclone the hybridoma
that produced BET-1 to try to solve the specificity problem, and
admitted that it could not be solved to Dr. Weaver, Dr. Eisen,
Dr. Baltimore, and Dr. O'Toole. See ORI FFCLs IX.D. We find
that Dr. Imanishi-Kari was aware that BET-1 was not absolutely
specific, but find that she had a basis for believing that it
discriminated adequately for her purposes. ORI did not establish
that she was concerned about solving a "BET-1 problem."
The claims that Dr. Imanishi-Kari "confessed" that BET-1 was
worthless turn out to reflect simply her immediate
acknowledgments that its specificity was not absolute, rather
than any denial that it adequately discriminated. This
misunderstanding was explained repeatedly by Drs. Eisen and
Baltimore, who initially were shocked and upset when they thought
Dr. Imanishi-Kari was telling them the former and then relieved
when they realized she was expressing the latter idea. Ex. H235;
Tr. 2084-86 (Baltimore). 93/
Dr. Maplethorpe testified that he overheard a conversation
between Dr. Imanishi-Kari and Dr. Weaver and a student working in
the laboratory in June 1985 in which Dr. Imanishi-Kari told them
that BET-1 was having problems in cross-reacting with æb, but
that Dr. Reis was recloning to solve the problem. Tr. 5714-16.
Dr. Maplethorpe claimed that he had clear recollections of this
overheard conversation because he tape recorded it. Tr. 5717.
We find that this testimony lacks credibility. Since Dr.
Maplethorpe and ORI failed to produce this supposed tape, to
explain its unavailability, or to produce the student who
allegedly participated, we infer that this tape either never
existed or does not support Dr. Maplethorpe's allegations. Dr.
Maplethorpe also claimed that BET-1 was never observed to act
with specificity in the lab and that it always cross-reacted so
that it could not be used to characterize the allotype of unknown
antibodies. Tr. 5757-58. We do not find this testimony reliable
since Dr. Maplethorpe testified that he based it entirely on his
memory of overhearing complaints about BET-1 and the fact that it
was no longer in use, but that he never reviewed any of Dr.
Reis's data (despite the fact that testimony demonstrated that
data were openly available in the laboratory for others to
review). Tr. 5757-58 (Maplethorpe), 2563-64 (Albanese), 1839
(Boersch-Supan), 2374 (Weaver), 2603-04 (Reis). As discussed,
our own review of the data belies his assertions, since there are
data showing that BET-1 behaves specifically in the notebooks
from Dr. O'Toole, Dr. Reis, and Dr. Imanishi-Kari.
ORI further argued that Dr. Imanishi-Kari's awareness of a
problem with BET-1 specificity was demonstrated by Dr. Reis's
efforts to reclone BET-1. See R-2:2-7. Dr. Reis and
Dr. Imanishi-Kari denied that problems with BET-1 specificity
were the reason for recloning. Tr. 2508-10 (Reis). Instead,
both testified that the purpose was to obtain additional
quantities. This testimony is supported by the fact that
hybridomas producing both allotype reagents were recloned at that
time, even though no allegation has ever been made that AF6 had a
problem with specificity. 94/ Tr. 4902 (Imanishi-Kari).
The literature cited in the Cell paper provided the reader
the available information on BET-1 specificity.
The BET-1 reagent was originally provided by Dr. Wortis, who
obtained it from the scientists who originally made it. Tr. 2783
(Wortis). The authors of the Cell paper included references to
papers in the literature about the allotype reagents. See Cell
paper 249. Scientific experts indicated that these papers
provided the knowledgeable reader with accurate information about
the specificity of BET-1. Tr. 1901-03 (Eisen), 2823 (Capra),
2784 (Wortis). It seems unlikely that Dr. Imanishi-Kari would
set out deliberately to mislead readers about the specificity of
a reagent and yet point them to literature disclosing the full
picture about the reagent.
The Cell paper did not materially mislead readers by
omitting more detailed reports of BET-1 specificity results
in other assays besides those in Figure 1.
ORI argued that the Cell authors were required to report
"representative" results of BET-1 specificity assays. ORI Br.
35-36. ORI quoted in support of this argument a statement from
the Bridges decision that standards for reporting research
require a scientist to "report conclusions which take all
available experimental data into account unless there is a
scientifically sound rationale for disregarding data." Bridges
DAB No. 1232, at 81. While accurate, this language is
inapposite. First, as explained, we have found that the results
in Figure 1 were accurately reported. Second, Figure 1 did not
purport to represent a survey of tests of BET-1's behavior.
While BET-1 was used in some important experiments in the paper,
the focus of the paper was not on studying this reagent, and, as
noted, any difficulty in achieving complete specificity by
allotype would not have greatly affected the central conclusions
of the paper. Third, several scientists testified that one does
not report every time a reagent fails to work, although a
researcher should not use experimental results when a reagent
does not appear to be working properly. Tr. 3135 (Marrack), 2069
(Baltimore). 95/ ORI did not allege that Dr. Imanishi-Kari used
results where BET-1 did not discriminate adequately. Fourth,
scientific journals have limitations on space for articles, so it
is not reasonable to expect that every experiment using or
testing every reagent would be described. See generally Tr. 2069
(Baltimore). Finally, and most importantly, we do not agree as a
matter of fact that Figure 1 and the results obtained with BET-1
there were seriously out-of-line with the experience of the
laboratory with the reagent or that contrary results were
disregarded without reason.
The Panel concludes that ORI did not prove charge one, Figure 1
by a preponderance of the evidence.
2. Alleged fabrication of related data
Figure 1, charge two: ORI charged that Dr. Imanishi-Kari's
"deliberate creation and reporting of falsified and fabricated
notebook data supporting Figure 1 at I-1:111-19; I-1:121 and I-
1:124-28A" constituted scientific misconduct.
Issue: The listed pages were challenged on the basis that Dr.
Imanishi-Kari submitted them as part of the I-1 notebook to
support her "story" about the specificity of BET-1. None of the
data from these pages were published in the Cell paper. Data
from I-1:121, however, were published in the letter of correction
to evidence BET-1's specificity. Ex. H3. ORI argued that the
forensic and statistical evidence demonstrated that the listed
pages were not authentic data from the purported dates. Since
these data were submitted to support the claims made about BET-1,
ORI alleged that fabrication of the listed pages constituted a
false report to investigators.
It is not clear that Dr. Imanishi-Kari ever identified these
pages as support for claims about BET-1 specificity. See
Response to findings in ORI's October 26, 1994 letter at 1
(January 31, 1995). These pages were submitted as part of the I-
1 notebook in response to a subpoena from the Subcommittee for
all data for the Cell paper and related experiments. Ex. H248.
Nevertheless, Dr. Imanishi-Kari did not dispute that intentional
fabrication of data on these pages would be scientific
misconduct; rather, she denied that she fabricated the data.
Id.; R. Br. 45-48.
Analysis: ORI alleged that these pages collectively presented a
"carefully wrought scenario" in the form of a story in which BET-
1 was problematic in March 1985 (I-1:111-113) but a new batch was
prepared and relabelled (I-1:114); somewhat better results were
obtained (I-1:115-118); 96/ and then by March 22, 1985, the
problem was solved and BET-1 was functioning reasonably
consistently with Figure 1 (I-1:119, 121, 125A, and 128A) and did
so from then on. Tr. 168 (Dahlberg); ORI Br. 41-42. The purpose
of fabricating this "story" was, according to ORI, to discredit
the assay in the 17 pages in which BET-1 failed utterly to
discriminate by allotype (R-1:18, dated May 7, 1985). ORI Br.
42. ORI asserted that, in reality, Dr. Imanishi-Kari told
Dr. O'Toole that BET-1 was not specific in March 1985 because the
clonal line was contaminated by a clone recognizing æb, but that
she would solve this by recloning. ORI theorized that Dr. Reis
attempted to reclone but the effort failed and the new clone was
not specific, and this lack of specificity demonstrated at R-1:18
could no longer be blamed on contamination of the clone. ORI
Report 89-90. Premised on this scenario, ORI presented
statistical and document examination findings about the listed
pages to support its claim that they were not authentic, at least
as to the dates when the data were purportedly generated.
Dr. Imanishi-Kari denied that these pages "purport to identify
and solve the problem of bad Bet' in a five-day period in March
1985." R. Br. 46; ORI Report 89-90, 185.
It is not disputed that Dr. Reis was in the process of developing
new clones to produce BET-1 around April/May 1985. R. Br. 46;
ORI Report 89-90; R-2:2-7; R-2:20. As discussed above, Dr. Reis
and Dr. Imanishi-Kari deny that this recloning was an effort to
solve problems with BET-1 specificity. Hybridomas producing AF6
and BET-1 were each recloned to obtain additional quantities of
the reagent. BET-1 from the new clones was used in subsequent
assays. Since the assays using BET-1 that appear in the
published paper dated from May not March 1985, Dr. Imanishi-Kari
had no reason to create a false impression that specificity
problems were eliminated in March 1985. We fail to see how such
an impression would discredit the assay on R-1:18 where BET-1
completely failed to discriminate, since that page is also dated
in May 1985.
Thus, the allegations that the dates were altered to place the
experiments on these questioned pages in March are not plausible.
The more successful experiments in the questioned pages are
simply more typical of the results obtained in the laboratory
throughout the time frame with BET-1, while R-1:18 is an anomaly
(in its complete lack of specificity) and an example of recurrent
instances where BET-1 was unreliable to varying degrees under
certain conditions. 97/ The questioned pages include examples of
experiments where BET-1 was relatively unspecific (with the
notations about bad labeling) (I-1:111-13); others where it was
specific to some extent (I-1:115-18); and some where it was quite
specific (I-1:119 and 121). The sequence would not have
established that all batches of BET-1 thereafter performed with
complete specificity since the assay at R-1:18 came later, but
only that, when conditions were right, BET-1 could perform well
and that control tests could successfully distinguish experiments
where BET-1 was not working so that the results of those
experiments could be discarded. If Dr. Imanishi-Kari were
attempting to discredit the R-1:18 assay by tampering with the
data record, it is more likely that she would remove other assays
in which BET-1's specificity was problematic and simply treat R-
1:18 as an anomalous failure. 98/ Conceivably, Dr. Imanishi-Kari
might also have annotated the pages with BET-1 specificity
problems to attribute the problems falsely to labelling. 99/
However, the idea that Dr. Imanishi-Kari took data from
unsuccessful experiments with BET-1 from months before or after
and intentionally misdated them to represent falsely that they
were performed in March 1985 is not believable.
Turning to the specific forensic findings, ORI pointed to the
register numbers on the counter tapes appearing on I-1:112
(continuing an assay begun on I-1:111 which is dated March 20,
1985) and I-1:116-17 (part of another assay running from I-1:115-
118 and dated March 21, 1985). The pages contain full-size
counter tapes with the following register numbers: 01447 (I-
1:112); 02799 (I-1:116); and 02800 (I-1:117). Mr. Stewart
testified that he did not see an advance of 1353 counter numbers
in one day in any of the other notebooks in this case. Tr. 3719;
see also ORI Report 70. Mr. Stewart also testified that the ink
intensities on the pages differed in that I-1:111-12 had quite
light ink and I-1:115-118 had medium dark ink. He did not
attribute this change to simply replacing the ribbon because the
ink on the former pages was not light enough for most people to
change and the ink on the latter pages was not dark enough to
represent a brand-new ribbon. Tr. 3718. Dr. Imanishi-Kari did
not disagree that these observations establish that the counter
tapes on these pages were probably not produced one day apart,
assuming they did come from the same counter. R. Br. 45; Ex.
H103, at 115-16. 100/
These tapes were preserved in full-sheet form with register
numbers whereas most of the tapes in the I-1 notebook were cut
into strips. ORI did not provide any explanation why
Dr. Imanishi-Kari would retain the register numbers on these
pages. Removing them would not only avoid providing any basis
for suspicion but would be the more typical pattern. 101/
As discussed before, the dates on the pages in the I-1 notebook
do not purport to represent necessarily the days on which the
assays were performed or the tapes generated. They may represent
a reconstruction of the time frame from protocols while
organizing the raw data at a later date or may be the dates the
pages were put together (possibly more by topic, since they were
obviously related in dealing with tests of BET-1) instead of the
dates of the assays. Dr. Dahlberg acknowledged that the tapes
may have been compiled over a one-day period, although they could
not have been generated in one day. Tr. 160. It is entirely
possible that the date on one or both of the assays is simply
wrong, and Dr. Imanishi-Kari conceded as much. R. Br. 45.
However, we do not think that an inference of intentional
falsification of the dates can reasonably be drawn from these
findings. If Dr. Imanishi-Kari were attempting to falsify data
to discredit the failed BET-1 experiment in the 17 pages, it
would be logical for her to construct a scenario where the "BET-1
problem" was solved in May, after the failed experiment and
before the experiments used in the paper (dated later in May).
By contrast, Dr. Imanishi-Kari had no plausible motive to
intentionally misdate these assays in March (nor any plausible
motive at all to include so many examples of "bad BET" in
supposedly fabricated pages).
The Secret Service attempted to guess the correct dates for these
pages on the basis of finding that the tapes did not match
examples found in other notebooks that bore dates around March
20, 1985. In addition, the I-1:111-12 tapes were found to be
"most consistent" with tapes from January 1985 and the I-1:115-18
tapes were "most consistent" with tapes from December 1985. Tr.
3744-46 (Stewart). While these findings suggest that the dates
on one or both of these assays are in error, we do not find the
effort to date them more accurately based on "consistency" of
ribbon ink very persuasive.
As discussed above, the meaning of "consistency" is only that a
tape happened to survive among those retained at MIT that had a
matching format and printer font and that had ink using the same
formula and at a reasonably similar intensity as the ink on a
questioned tape. If such a tape occurs in any other researcher's
notebook, the Secret Service and ORI extrapolated from the date
in that notebook to find the "correct" date for the questioned
tape. Yet the "consistent" tape may have come from a different
counter or printer, may have been produced with a different
ribbon, and may have been dated incorrectly by the other
researcher. The absence of a "consistent" tape in a given time
frame does not demonstrate that such tapes did not exist.
We therefore find that the tapes at I-1:111-12 and 1-1:115-118
were probably dated incorrectly, but that ORI did not show that
these tapes did not represent authentic experiments or that they
were intentionally misdated in a deliberate effort to
misrepresent the chronology of BET-1 experiments.
ORI offered different forensic arguments as to the remaining
pages. We address first the arguments about I-1:113 and 119
(which concern document examination evidence on when those pages
were compiled). 102/ We then address the document examination
evidence offered in regard to the handwritten BET-1 data on I-
1:121, I-1:125A and I-1:128. However, the main attack on the
last three pages was statistical and is discussed in detail in
relation to the statistical analysis of the June subcloning data
and the charges regarding Table 2.
Page I-1:113 is not dated, but ORI assumed that its placement in
this series of pages was intended to imply a date in March 1985
for the experiments recorded there. 103/ However, the Secret
Service offered several findings regarding this page to support
the conclusion that it was created after February 1986. These
findings did not address the raw data on the counter tapes. They
are based on characteristics of the page onto which the data were
compiled, such as the pad paper and ink used (which were used in
other pages date in 1986) and the connection of ESDA impressions
of the writing on this page with 1986 pages.
We consider the details of these findings below, but even
assuming their accuracy and the validity of the conclusion drawn
that this page was compiled in early 1986, we would find no basis
to infer that the data were fabricated or intentionally falsified
as to date.
The findings about I-1:113 were based on linking it to three
other pages from I-1: 30, 41 and 43 and to a page from another
Dr. Imanishi-Kari notebook: I-3:25. 104/ The Secret Service
found that these pages were connected in that they used pad paper
that contained the same defects 105/ and had writing using the
same black ballpoint pen ink formula. 106/ Ex. H500, at 3. As
discussed above, the Secret Service found nothing unique about
the ink formulas or pad defects that would demonstrate that they
came from a specific time period 107/ or that a single pad or pen
was the source of pages that happen to have the same defect or
ink formula. 108/ Tr. 4185 (Stewart) ("You cannot determine if
it's the same pen. That's impossible."). In addition, the
Secret Service found nothing remarkable "on the surface" about
the same ink formula appearing on 1984 and 1986 documents. Tr.
4188 (Stewart).
However, the Secret Service attributed significance to the
collective findings in light of ESDA results which also linked
some of these pages as having been produced close in time, or at
any rate on top of, each other. Tr. 3974-75, 4188 (Stewart); Ex.
H500, at 2; ORI Br. 45. No direct ESDA connection existed
between I-1:113 and any page from I-3, but the Secret Service
found that an impression of I-1:41 appeared in registration on an
ESDA of I-1:113 (leading to a conclusion that I-1:41 was produced
"prior to" I-1:113). 109/ In addition, an impression of I-3:25
was found on an ESDA of I-1:30, so the Secret Service concluded
that the I-3 page from 1986 was produced before the page from I-1
dated in 1984. Tr. 3276-81, 3284-85 (Hargett). Since I-1:30 was
connected in turn to I-1:41, by the pad and pen commonalities,
the Secret Service extrapolated that all these pages were in fact
produced at around the same time. Tr. 3313-14 (Hargett); Ex.
H505.
In addition, Dr. O'Toole testified that I-1:41 and I-1:113 were
shown to her in May 1986 when she met with Drs. Wortis, Woodland,
Huber and Imanishi-Kari. She described I-1:41 as "brand spanking
new" and testified that Dr. Imanishi-Kari told her that she
"deeply resented having to take time to generate" the data to
satisfy Dr. O'Toole. Tr. 985-87. We find it implausible, were
Dr. Imanishi-Kari guilty of having fabricated these pages
immediately before the meeting in order to satisfy Dr. O'Toole,
that she would promptly complain to Dr. O'Toole of the trouble it
involved to fabricate the data. 110/ We find it far more likely
that Dr. Imanishi-Kari was resentful of having to take time to
locate the data, or perhaps to organize the raw data on to the
pages for Dr. O'Toole. 111/ As for the supposedly suspicious new
condition of page I-1:41, that may have resulted from its
relatively recent compilation or its storage in a manilla folder.
R. Br. 87. 112/
After reviewing the contents of these pages, we find it difficult
to credit the claim that Dr. Imanishi-Kari fabricated these data
out of whole cloth to satisfy Dr. O'Toole at the Wortis meeting
(presumably along with I-1:30, 41, 42 and 43, since these are
grouped together by the Secret Service). Page I-1:113 shows
BET-1 behaving in a very sticky fashion, and it is not disputed
that Dr. Imanishi-Kari wrote on the page at the meeting that this
BET-1 had a "bad label." If she were fabricating data, she could
as easily have fabricated only the AF6 data showing endogenous
idiotype-positive hybridomas and omitted the problematic BET-1
results. 113/ She could also have fabricated clear-cut examples
of idiotype-positive endogenous þs that were negative for æ
(which would have been even stronger evidence for her position).
If it was so much trouble to generate data for this meeting, the
data on these challenged pages were certainly not worth the
trouble or risk.
ORI attacked the authenticity of the date (March 22, 1985) on
page I-1:119 as well. Dr. Imanishi-Kari testified that I-1:114,
which is a page from the spiral notebook, was probably the
protocol for I-1:119 which contains results of assays of samples
that are mostly listed on I-1:114. Tr. 5260-61. However, she
said that she believed that she dated I-1:119 with reference to
I-1:114, so that the date might not be accurate but only
estimated based on the assumption that this experiment was the
one referenced on I-1:114. Id.; see also Tr. 5263-65 (on I-
1:115-20); R. Br. 46-47. The Secret Service found that
impressions of parts of I-1:119 showed up on ESDAs of I-1:7, 8,
and 9 (all dated in August 1984), from which they concluded that
I-1:119 was created before the other three pages. ORI Br. 47;
Tr. 3461 (Hargett); Ex. H500, at 1. This evidence might at most
suggest that I-1:7, 8, and 9 were compiled some time after the
dates noted for the experiments on them but does nothing to
demonstrate that I-1:119 could not have been compiled in Spring
1985. 114/
ORI also pointed out that the date on I-1:119 was changed from
12/16 to 3/22/85. ORI charged that the counter tapes on I-1:119
were not consistent with other researchers' tapes from either
"the original or changed date." ORI Br. 47; Exs. H501, at 2 and
H502, at 2-3. As explained elsewhere, we attach no particular
importance to the absence of matching tapes in any particular
time frame among the sample of counter tapes reviewed. Nor do we
see any special significance to a change from December of 1984 or
1985 to March 1985 -- Dr. Imanishi-Kari may have begun writing
the page with one idea of the probable date and either changed
her mind about which experiment the tapes recorded or used the
page for a different experiment than she initially planned to
record. If Dr. Imanishi-Kari were changing the date in an
intentional attempt to mislead, it is far more likely she would
have changed the date to one in May (between the failed
experiment in the 17 pages and the important experiments using
BET-1 that are reported in the paper).
We turn next to I-1:121, which was dated in May 1985 and was
indeed published in support of BET-1 specificity. ORI made a
similar argument that the ESDA of I-1:5 (not dated but associated
with pages dated in August 1984) showed that I-1:121 was produced
first. Dr. Imanishi-Kari pointed to internal evidence for
I-1:121 which ORI acknowledged was "certainly consistent with
the" date on the page, i.e., a reference to "Pool 1" which was
the new cloning of BET-1 prepared by Dr. Reis in late April and
early May 1985. ORI Br. 48. Furthermore, Dr. Imanishi-Kari
explained in her testimony before Congress that these two pages
were connected scientifically in a way that made it perfectly
logical that she "would be reviewing, comparing and/or recording
the data from these two separate experiments at the same time,"
an explanation which she verified at the hearing, noting that she
might have wanted Dr. Reis to have access to normal mouse data on
I-1:5. Ex. H120, at 148; Tr. 5169-71. Mr. Hargett rejected the
possibility of an innocent explanation because taking notations
from page 5 to put on 121 or shuffling the pages to copy data was
not consistent with the finding that I-1:121 was produced on top
of I-1:5. Tr. 3396 (Hargett). Yet Mr. Hargett admitted that, of
all the data appearing on I-1:121, very little actually appears
on the ESDA of I-1:5. Tr. 3453-54. Mr. Hargett acknowledged
that if I-1:121 were actually created on top of I-1:5 (the
assumption that underlies any inference that I-1:121 was produced
"prior to" I-1:5), he would have expected more of the contents of
I-1:121 to show in the impression. Id. Asked if it was possible
that these were loose pages that were simply placed together in
registration briefly when this small portion was written,
Mr. Hargett answered that "[o]n this particular page, that could
be a possibility, yes." Id.
Although ORI also listed I-1:124-128A in this charge because some
BET-1 data appears on I-1:125A and "minimal BET-1 specificity
results" are included on I-1:128, the bulk of the arguments
concerning these pages (known as the "June subcloning" data) are
more relevant to Table 2. ORI Br. 48. The statistical challenge
to I-1:121 is better discussed in the section on the June
subcloning. The premises of the statistical attack are the same
although the page is not part of the same data set. We note here
only that Dr. Imanishi-Kari also pointed out that only 12 of the
72 entries on I-1:121 are related at all to BET-1 and the
statistical analysis did not consider those entries separately.
R. Br. 48. We explain in the later section why we conclude that
ORI did not prove that these pages were fabricated or falsified.
The Panel concludes that ORI did not prove charge two, Figure 1
by a preponderance of the evidence.
B. Table 2
The authors of the Cell paper present Table 2 as support for a
dramatic difference in the frequency of idiotype-positive
antibodies between hybridomas from transgenic and normal mice.
In addition, Table 2 shows that a high proportion of the
idiotype-positive antibodies produced by the transgenic
hybridomas probably were derived from endogenous genes. Since
the transgene carried the æa allotype, any idiotype-positive
antibodies which were not æa could be assumed to be derived from
genes other than the inserted transgene. Thus, for example, the
report in Table 2 that only nine out of 43 transgenic spleen
hybridomas produced idiotype-positive antibodies with the æa
allotype implied that the remaining 34 hybridomas producing
idiotype-positive antibodies were endogenous (one being æb, and
the remainder presumably of other isotypes such as þ or à). 115/
ORI charged that Table 2 exaggerated the frequency of idiotype-
positive endogenous antibodies in the transgenic mice in two
ways. First, that the cut-off used to determine a positive
result in the assays was set too low so that a misleadingly high
number of transgenics were considered positive. Second, that the
results were presented as if they had been obtained with
antibodies from individual clones, whereas in fact the assays
were performed on supernatants from wells which might contain
more than one clone. In addition, ORI challenged the data on
normal hybridomas in several respects.
1. Cut-off questions
Table 2, charge one: ORI charged that Dr. Imanishi-Kari
"deliberately set the cut-off values to produce artificially high
and misleading results" and thereby produced "misleading
statements of the experimental results reported in Table 2."
Charge letter 4.
Issue: Table 2 compared the frequency of idiotype-positive
hybridomas derived from spleen and lymph node cells of normal
mice with those from spleen and lymph node cells of transgenic
mice. In addition, for each category of hybridomas, the
idiotype-positive hybridomas were grouped by testing them for
anti-NIP response (using kappa and lambda light chain probes) and
for æa and æb allotypes. Table 2 reported that 43 (28%) of the
transgenic spleen hybridomas and 129 (68%) of the transgenic
lymph node hybridomas were idiotype positive. By contrast, only
one idiotype-positive hybridoma (less than 1%) was reported for
either set of the normals. 116/ This difference, along with the
allotype information showing that only about a quarter (42/172)
of the transgenic idiotype-positive hybridomas produced the æa
(transgenic) allotype, was critical to the central point of the
paper about the high frequency of endogenous idiotype-positive
transgenic hybridomas. Tr. 2771-72 (Wortis).
The data for idiotype positivity reported in Table 2 for the
transgenic hybridomas came from R-1:31-34 (included in the 17
pages copied by Dr. O'Toole). The determination that a hybridoma
was idiotype positive in that assay was based on a cut-off of
1000 cpm. 117/ The data at R-1:31-34 show the cpm only for those
hybridomas which exceeded 1000, so that negative results were not
retained. ORI argued that this cut-off was too low because the
listed readings cluster around 1000 cpm; ORI contended that the
cut-off should have been chosen at the low point of a bimodal
distribution dividing positives from negatives. Tr. 288-295
(Dahlberg); ORI Report 104-06. 118/ Dr. Imanishi-Kari responded
that she used a different but generally accepted method to set
the cut-off by roughly doubling the background counts. 119/ ORI
admitted that the scientific witnesses, including its own,
considered this method "perfectly appropriate . . .
theoretically." ORI Br. 56. However, ORI denied that this
method was actually applied, because control data on R-1:34 show
a background value of 738, which would yield a cut-off of about
1500-1800 and a much lower number of idiotype-positive transgenic
hybridomas. Dr. Imanishi-Kari argued that the controls
referenced actually applied to a different experiment, also
reported on the same pages, where some of the hybridoma
supernatants were retested ("June 6th retest"). Tr. 4862.
Analysis: As an initial matter, ORI suggested that there was a
dispute about the degree of Dr. Imanishi-Kari's responsibility
for problems with Table 2. Dr. Imanishi-Kari denied that she was
primarily responsible for this table, and ORI charged that this
disavowal was inconsistent with Dr. Imanishi-Kari's
acknowledgment that she helped set the cut-offs, supervised and
worked with Dr. Reis, and provided the serology data in the
drafting process. Tr. 4692, 4869, 5422 (Imanishi-Kari); ORI Br.
54-55. We find that Dr. Imanishi-Kari had overall responsibility
for the presentation of the serological results and that she
worked closely with Dr. Reis, but that this role is not
inconsistent with her relying on Dr. Reis's representations and
interpretations of results from experiments which Dr. Reis
conducted.
Interpreting the results of a particular assay is at the heart of
scientific judgment. The definition of scientific misconduct
expressly excludes honest differences of interpretation, and ORI
represented that its charges here are premised on intentional and
deliberate acts of misrepresentation by Dr. Imanishi-Kari.
Therefore, we would sustain this charge only if we found that the
cut-off used was inappropriate and was selected in an intentional
and deliberate effort by Dr. Imanishi-Kari to mislead readers,
and not if we found only that other methods of selecting a cut-
off might be acceptable or even preferable. 120/
Because Dr. Reis wrote down only counts 1000 cpm or above, an
after-the-fact reevaluation of the appropriateness of the cut-off
selected based on the distribution of results is difficult. 121/
Fortunately, the argument that a bimodal distribution is the
correct way to set cut-offs is largely moot in light of the
overwhelming weight of the scientific testimony that a low
multiple of the background count was an acceptable method. See
Tr. 1547 (Gilbert), 2772-76 (Wortis), 1943-44 (Eisen). ORI seems
to have recognized this as well since this argument is not
pressed in its post-hearing brief. See ORI Br. 55-60. The real
issue, therefore, is whether the method was in fact used here, as
Dr. Imanishi-Kari testified that it was. 122/ Tr. 5428.
The basis for ORI's conclusion that Dr. Imanishi-Kari did not use
a low multiple of the background count is that control data on
the bottom of R-1:34 show a background value of 738. ORI
rejected Dr. Imanishi-Kari's assertion that these controls
related to the June 6th retest (and that the controls for Table 2
are missing), for several reasons. First, the Table 2 assay was
larger so controls would have been more important for it. By
contrast, ORI argued, the retest would not require so many
controls, especially the controls for AF6, which was not used in
the retest.
While ORI is obviously correct that the main assay would have
required controls, as would the retest, we do not find a basis to
conclude that if one set of controls was lost inadvertently, it
was more likely to be the controls for the retest than those for
the main assay. As for the inclusion of AF6 controls,
Dr. Imanishi-Kari answered that they might well have decided not
to proceed with an AF6 assay in the retest because of the
extremely high background count. Tr. 4861. Dr. Reis
corroborated this testimony. Tr. 2532-33. ORI disputed this
possibility on the grounds that the BET-1 background was also
high and yet that assay proceeded. ORI Reply Br. 28, n.36.
However, the background for the AF6 control was more than twice
as high as the BET-1 background (although the latter was also
higher than ideal). Dr. Imanishi-Kari argued (and ORI did not
dispute) that no other assay in her own or Dr. Reis's notebooks
had a comparable background for AF6, whereas BET-1 had had more
history of high backgrounds. Therefore, it is plausible that
Dr. Imanishi-Kari's and Dr. Reis's scientific judgment was that
it was worth proceeding with the BET-1 retest under the
circumstances, but not with the AF6.
The results reported in Table 2 are consistent with the testimony
that a different set of controls, now missing, was used for the
main assay. In particular, using the high background shown for
BET-1 would eliminate most of the positive results recorded in
Table 2 for æa (dropping from 41 to 7). Yet, Dr. Imanishi-Kari
had no motive to inflate the number of BET-1 positives. ORI
acknowledged that these backgrounds were not used to set cut-offs
for the main assay, but argued that perhaps Dr. Imanishi-Kari and
Dr. Reis just ignored these controls and that, in any case,
applying these high backgrounds would have reduced the number of
æb (i.e., endogenous) idiotype positives (which Dr. Imanishi-Kari
did arguably have a reason to inflate) even more, from 10 to 0.
ORI Reply Br. 28-29. It does not seem plausible that
Dr. Imanishi-Kari and Dr. Reis retained the records of these
backgrounds (and left them in accessible place in the laboratory)
if they knew they applied to the main fusion assay but were
deliberately ignoring them to set arbitrary cut-off levels. If
they were setting the cut-offs arbitrarily to oversell their
results, they had no reason to report higher levels of æa
positive than required even by the recorded background. Had the
controls on I-1:34 in fact applied to the main assay, the
reported results for both the AF6 and BET-1 portions of the main
assay would have been very different.
Dr. Imanishi-Kari also pointed out that Dr. Reis used the same
cut-off in assessing positivity in the "normal" mouse portion of
the assay. R-1:27-30; R. Br. 49. The authors certainly had no
reason to inflate the number of idiotype positives in a normal
mouse. 123/ That the cut-off successfully distinguished real
positives is evidenced by the fact that the normal mouse was
discovered to be transgenic because this assay was
indistinguishable from the high rate of positives found in the
transgenics. 124/ This evidence supports the testimony of Dr.
Reis that the controls were for the retest, especially based on
the higher counts in the controls which were more in keeping with
the results of the retest than of the initial screen. Tr. 2530,
2617. 125/
ORI made two other arguments, however, to bolster the position
that the recorded controls related to the main fusion assay.
First, Dr. Dahlberg and ORI claimed that ESDA results indicated
that the June 6th retest data were not entered on R-1:34 at the
same time as the results for the main fusion assays or the
control data. ORI Br. 58-59; Tr. 252-53. 126/ This assertion is
repeated in ORI's proposed FFCLs. ORI FFCL X.G.6. Not only did
the Secret Service make no such finding, an examination of the
ESDA for R-1:35 directly contradicts this claim. 127/ The ESDA
of R-1:35 contains impressions of both the June 6th retest
results and portions of the control data, but none of the results
of the main fusions assays. This independent observation
strongly supports Dr. Imanishi-Kari's and Dr. Reis's memory that
the controls related to the June 6th retest and not the main
fusion assay. Second, ORI pointed out that the controls included
tests on a NIP coat. An independent assay on a NIP coat was also
done on the main fusion products while no NIP coat assay was
performed as part of the retest. Dr. Imanishi-Kari argued that
these controls on the NIP coat could represent those for the
independent NIP assay of the main fusion experiment or
preparation for a further assay on the retest that was not
performed. R. Br. 51, n.61.
The Panel's review of other assays in the I-1 notebook showed
that many are consistent with Dr. Imanishi-Kari's assertion about
the method she used to set cut-offs (as the NIH Scientific Panel
also noted about the immunoassays which it reviewed). For
example, in the assay at I-1:3-6, the controls showed background
counts of 267-456. It is evident that a 1000 cpm cut-off was
used, since three positives were recorded, with the lowest
positive at 1105 cpm. In support of its position that
Dr. Imanishi-Kari used a 1000 cpm cut-off here arbitrarily in
order to misrepresent the percentage of idiotype-positive
transgenic hybridomas, ORI alleged (in its report, although the
point is not pressed in its brief) that other assays in
Dr. Imanishi-Kari's and Dr. Reis's notebooks demonstrated that a
1000 cut-off was not always used. Tr. 302-04, 552-53 (Dalhberg);
ORI Report 107-10. Of course, Dr. Imanishi-Kari did not claim
that she always used 1000 cpm as a cut-off (which would be rather
arbitrary) but rather that she generally used roughly twice
background but not lower than 1000. Therefore, assays in which a
cut-off above 1000 was selected would be potentially inconsistent
only if they reflected background levels of below 500.
As an example, ORI pointed to the assays on I-1:101-09 (known as
the January fusion). 128/ ORI questioned the authenticity of
these data but nevertheless argued that they showed
Dr. Imanishi-Kari consciously using a different cut-off in that
the totals for the experiment shown on I-1:105 were initially
based on a 1000 cpm cut-off and then were crossed out and new
totals were written based on a 2000 cut-off. It is odd for ORI
to rely on this assay for any purpose while denying its
authenticity. In any case, the revision of the totals, if
anything, supports Dr. Imanishi-Kari's version of how she set
cut-offs. The background counts on I-1:104 ranged from 248 to
820. Hence, relying on the lowest background would yield a 1000
cut-off (since she testified she did not go below 1000) while two
and one-half the higher background would yield 2000. On
reflection, Dr. Imanishi-Kari apparently decided to use the more
conservative figure even though it reduced the level of idiotype-
positivity on the transgenic screen from 79% to 60%. See ORI
Report 107-08; R. Br. 51-52.
ORI also pointed to R-1:71-76 where Dr. Reis performed four
fusions using mice immunized with chicken gammaglobulin, three
fusions with transgenic mice and one with a normal mouse, and a
fusion with a normal unimmunized mouse, the last of which was
part of the normal data reported in Table 2. Cf. ORI Report 108-
09. 129/ The cut-off in the transgenic fusions was allegedly
5000 cpm while 1000 was used for the normal unimmunized portion.
130/ Dr. Imanishi-Kari responded that these transgenic assays
were not analogous to the transgenic fusion assay at R-1:31-34
because, in the experiments on mice immunized with chicken
gammaglobulin, "Dr. Reis was looking for transgene expression,
which would be manifested by very high cpms," whereas in the R-
1:31-34 assay, she "was looking for idiotype positives even from
endogenous genes," which would be manifested by lower cpms and
therefore only be picked up by a more sensitive cut-off level.
R. Br. 52, n.63. (We discuss the relation of the immunized
transgenic and unimmunized normal fusions further in relation to
charges concerning Table 2.) ORI did not contest this
representation in its reply brief, so we do not infer from the
use of a different cut-off in R-1:71-76 that the cut-off in R-
1:31-34 was not set by the method explained by Dr. Imanishi-Kari.
The Panel concludes that ORI did not prove charge one, Table 2 by
a preponderance of the evidence.
2. Wells v. clones issue; "June subcloning" data
Table 2, charges two and three: ORI charged that
Dr. Imanishi-Kari's failure to disclose that "the frequency
values reported in Table 2 were derived from wells, not
individual hybridomas" was "a deliberate misrepresentation of
data." Charge letter 4. Further, ORI charged that
Dr. Imanishi-Kari committed scientific misconduct by her
"deliberate creation and reporting of the fabricated and
falsified data at I-1:124-128A [June subcloning] to support the
prior published results in Table 2. . . ." Charge letter 4.
Issues: As explained in relation to the first charge, Table 2
presented data comparing the frequency of certain characteristics
in the products of normal and transgenic "hybridomas." In the
text discussing this table, the paper stated: "Of the 172
idiotype-positive hybridomas, only 53 were IgM secretors.
The remaining 119 clones produced other Ig heavy chain
isotypes . . ." Cell paper 250 (emphasis added). It is not
disputed that the assays were performed on the supernatants of
parent wells of a fusion without further cloning to ensure that
they represented individual cell lines. This was clarified by
the authors in two letters of correction. Exs. H2 and H3. 131/
Dr. Imanishi-Kari contended that this was a problem in
terminology that was, at most, an error, but which was not
intended to mislead. ORI contended that not only was the
terminology a deliberate misrepresentation, but that
Dr. Imanishi-Kari submitted to NIH fabricated and falsified data
to show that the results of further subcloning supported the
frequency reported in Table 2.
Analysis: We deal first with whether the use of the terms
"hybridoma" or "clone" in the paper constituted a deliberate
misrepresentation. Next, we turn to whether the data ORI
referred to as the "June subcloning" data were intended to
support the Table 2 frequency results and, if so, whether ORI
proved that they were fabricated or falsified.
We note at the outset that the term "June subcloning" data used
by ORI is not technically accurate since the data are presented
as related to the first level of cloning from parent wells. This
shows how easily such terms can be misused. We use the term
"June subcloning" data below to avoid confusion since the parties
and their witnesses repeatedly used that term. We specifically
disclaim any implication that we consider this to be correct
usage of the term.
The terminology used for fusion products was erroneous and
overstated somewhat the frequency results, but was not
deliberate misrepresentation.
The NIH Scientific Panel reviewed the issue relating to
terminology in Table 2 and noted that the data, "contrary to the
impression given in the Cell paper, are the result of studies
performed on supernatant culture fluids from wells containing
hybridoma fusion products prior to limiting dilution cloning."
Ex. H262 (NIH Scientific Panel Report at 5). The effect of
reporting data on uncloned hybridoma fusion products was that the
percentage of idiotype-positivity was "likely lower" than
reported for the transgenic mice, perhaps between 20 and 40%.
Id. at 5-6. The NIH Scientific Panel concluded that the
presentation in Table 2 was "incorrect," but felt that the
results of the June subcloning data supported "the trend seen in
Table 2." Id. (NIH Scientific Panel Report at 6). Therefore,
NIH required the authors to publish the second correction and
include the subcloning data. Ex. H262 (Report to NIH Director,
January 18, 1989, at 13).
Another basis for estimating the significance of the error is to
consider the probable number of clones per well, since the more
wells that had only one clone, the closer the idiotype
frequencies reflect characteristics of individual clones. ORI
stated that "it is unrebutted that [the wells for the Table 2
transgenic fusion] contained, on average, about 1 clone per well
for the spleen wells and 1.5 clones per well for the lymph node
wells." ORI Br. 63; ORI Report 122-24. 132/ ORI's own
calculation was that the reported frequencies of 28% and 68% for
transgenic spleen and lymph nodes respectively would drop to 20%
and 50%. ORI FFCL X.J.12. A number of scientific experts
testified that a reduction of this magnitude would not affect the
central point of the paper (which is in accord with the NIH
Scientific Panel's conclusion that its calculation of the lower
percentages did not undercut the paper). Tr. 2770 (Wortis), 3116
(Marrack); Ex. H299, at 2. 133/ Since the difference in
frequency values reported was not so substantial as to affect the
main point of the paper, we conclude that it is not likely that
the terminology was chosen with an intent to mislead.
Dr. Imanishi-Kari explained the reasoning process of the authors
in believing the frequency data on the products of the primary
hybridomas were significant. Even though "each well might
contain more than one clone . . . the striking finding was that
there were many wells that were idiotype positive and Bet 1 (æa)
negative. This indicated that these wells contained at least one
hybridoma clone producing idiotype and no clone producing
transgene." Ex. H255, at 2. Thus, from this point of view, an
additional clone in one of these wells was insignificant since it
must either be endogenous idiotype negative (and basically
irrelevant to the argument that idiotype-positive antibodies from
the transgenic hybridomas were mostly encoded from endogenous
genes) or endogenous idiotype positive (and hence further support
the argument). While reasonable scientists might differ in
interpreting these data, this summary persuasively demonstrates
that the decision to publish these frequency data was not
intended to deceive readers. 134/
This conclusion is bolstered by our independent review of the
notebooks generated in Dr. Imanishi-Kari's laboratory at the
relevant time. Not only Dr. Imanishi-Kari and Dr. Reis, but also
Dr. Weaver and Dr. O'Toole, frequently were inconsistent or
imprecise in the language used in their laboratory notebooks to
designate the level of cloning dilution with which they were
working in various fusion experiments. Thus, the terms "hybrid"
or "hybridomas" were used often to denote wells potentially
containing mixtures of clones; "subclone" and "clone" were used
indiscriminately, often to describe the same experimental
products. One example observed in Dr. O'Toole's O-2 notebook
uses the term "hybridomas" as a heading, even though products of
primary hybridoma wells are involved; and another experiment in
Dr. O'Toole's notebook dated August 26th (no year) is headed
"First cloning from parent hybridoma wells" and thereafter called
"subclones." 135/ Dr. Baltimore testified that he was aware that
Table 2 did not report on single clones before the paper was
published, but that, in the process of the collaboration in
drafting, he "certainly let it slip by." Tr. 2087-88.
Therefore, the error in terminology may be an outgrowth of
"laboratory jargon" that was not properly edited out. 136/
The uncertainty about precise terminology in this area was
highlighted by the disagreement between scientific expert
testimony and ORI's claim that the term "wells" should have been
used instead of "hybridomas." Dr. Marrack, asked what
"hybridoma" means, testified as follows:
A A hybridoma is a fusion between one cell and
another . . . .
Q And does the term hybridomas necessarily connote single
clones?
A No. Because I think we use the word hybridomas, at least
in my lab we do, to describe the process where, for example,
one's done a fusion then we are screening the wells visually
to see whether or not they've got hybridomas in them, and
you will say there's a well with a hybridoma in it, if
something is growing in it at that time. . . . And at that
time the object would certainly not have been cloned.
Tr. 3113-14. Asked if it would have been better to say
"idiotype-producing wells," Dr. Marrack testified that the term
"wells" would be wrong because "the wells are not the growing
organism that you're looking at. The cells themselves that are
in the well are the things that are producing the
antibody . . . . So the word hybridoma applies to the growing
fused cells that are living in the well." Tr. 3114. The point
is not that the terminology used was necessarily correct (at
least, the use of "clones" in the text of the Cell paper was
clearly inaccurate). Rather, the point is that, contrary to
ORI's contentions, it is plausible that mix-ups and differences
in the use of this terminology might occur even among experts in
the field and that the precise use of terms may vary in different
laboratories. Cf. ORI Br. 60-61.
Although ORI alleged that a "typical scientist reading" the Cell
paper would have believed that the frequencies reported were for
individual hybridomas, the scientists testifying at the hearing
were divided on this question. ORI FFCL X.J.8; see, e.g.,
Tr. 3115-16 (Marrack). Dr. Marrack testified that an assay on
this scale could never have been done with individual clones, and
"anybody with common sense would have known that you couldn't
possibly have cloned that many." Tr. 3115-16; Ex. H255, at 2.
ORI rejected this argument as unreasonably assuming that "all
possible readers of the paper are experts in the particular field
of serology . . . [and] have or expect resource limitations" like
those faced by Dr. Imanishi-Kari. ORI Br. 61. While such an
assumption would indeed be unwarranted, ORI's response misses the
point. Not all possible readers might be in a position to
discover the error, but it is less likely that the incorrect
terminology would be selected intentionally to deceive when the
high numbers of hybridomas being reported upon could in itself
cause any expert immunologist to question the table's
plausibility, especially since Dr. Imanishi-Kari can be assumed
to have known that many such experts would be in the audience of
this journal.
Since we do not find the June subcloning data to have been
fabricated and falsified (discussed separately below), we see no
reason to go beyond what the prior NIH Scientific Panel did in
correcting the misimpression created by the terminology in Table
2 and the text. Our review of the science supports the
conclusion that the language used in the paper was confusing and
the percentages were overstated by the implication that the
references were to single clones. Our review also supports the
conclusion that the error did not undercut the central point of
the paper and did not indicate intentional or deliberate
misrepresentation.
ORI did not prove that the June subcloning data were
fabricated.
Description of the questioned data: The results at issue which
have become known as the "June subcloning" data, as presently
organized, consist of nine pages of the I-1 notebook (I-1:124-
128A) which present the results of tests of supernatants of sets
of 12 "subclones" derived from each of 16 primary hybridoma wells
(from Table 2). The supernatants were tested on an anti-idiotype
coat with four detecting probes: anti-kappa/lambda; BET-1; AF6;
and anti-æ. The actual results are contained in four columns,
one for each detecting reagent, over seven pages. Page I-1:125A
presents results of tests against control proteins. Page I-
1:128A summarizes the assay results. The results for the tests
with the anti-light chain reagent are in the form of strips of
green counter tape in the left-most column. The results in the
other three columns are written by hand.
Scientific arguments
The authenticity of the June subcloning data became an issue
because they were submitted to the NIH Scientific Panel and
published at their recommendation in the correction letter to
confirm the frequency results. Ex. H3. ORI apparently agreed
that, if authentic, the June subcloning data support the Table 2
claim that the "vast majority of idiotype-positive hybridomas
were of endogenous isotype." ORI Br. 63.
The scientific significance of the data set is limited. First,
as noted above, internal evidence of the pauci-clonality of the
Table 2 wells confirms the trend in the results without reference
to any subcloning. In fact, Dr. Dahlberg testified that the
reason that the NIH Scientific Panel was distressed by the
terminology issue in Table 2 was "because they didn't appreciate
at the time what the level of clones per well was." Tr. 323-24.
Second, subcloning from selected primary hybridomas from wells
does not give direct information about the frequency of
characteristics in the parent population. The authors indicated
this in their response to the draft report of the NIH Scientific
Panel. Ex. H259, at 16 (November 28, 1988). While not objecting
to publishing the data, the authors stated that subcloning data
should be a supplement to, not a replacement for, the Table 2
data because the "subclone data are less significant, because
they are a subset." Id. If Dr. Imanishi-Kari were fabricating
data in 1988 to satisfy NIH's concerns, it would seem likely she
would either fabricate data that did represent a population, or
at any rate would not point out the limited value of the data she
had created. 137/ The data and her handling of them (as an
interesting follow-up experiment but not a substitute for the
Table 2 data) are more consistent with the view that she was
exercising scientific judgment than with fabrication.
Dr. O'Toole has asserted in several fora that Dr. Imanishi-Kari
told her that no subcloning of the Table 2 wells was ever done,
and that Dr. O'Toole therefore believed (before any forensic
testing) that the June subcloning data were fake. Tr. 6121-22
(O'Toole); Exs. H276, at 9, H258, at 3, H296, at 1-2, H282, at
12, H290, at 9. Dr. Imanishi-Kari has contended that Dr. O'Toole
"misconstrued" what Dr. Imanishi-Kari told her, "which is that no
serological tests on those wells other than those contained in
the 17 pages' were performed." Dr. Imanishi-Kari's Statement in
Response to Dr. Margot O'Toole's Record of Events at 4 (Part of
Ex. H298). ORI itself apparently was not persuaded by
Dr. O'Toole, since it asserted that "ORI does not contend that no
subcloning of these clones ever occurred; ORI simply contends
that the data at issue is not authentic subcloning data, if and
when such subcloning did occur." ORI Reply Br. 29. 138/
The conclusion that "subcloning" did take place is amply
supported on the record, not only by testimony of
Dr. Imanishi-Kari and Dr. Reis that they performed the
experiments, but also by the testimony of Dr. Baltimore that he
discussed the results with Dr. Imanishi-Kari before the paper was
published. Tr. 2105-08 (Baltimore). In addition, there is
credible evidence that the data now known as the June subcloning
data were available the first time Drs. Woodland, Wortis, and
Huber met with Dr. Imanishi-Kari on May 16, 1989.
Dr. Imanishi-Kari testified that she showed the June subcloning
data to them at that meeting, and all three testified that they
remembered seeing those data. Tr. 4963 (Imanishi-Kari), 2800-01
(Wortis), 1805-06 (Huber), and 1699 (Woodland). Dr. Huber
testified that she "definitely" remembered "that the subcloning
of these hybridomas from Table 2 was discussed" and that "Thereza
showed us radioimmunoassay data from subclones from these
hybridomas," and "to me, that was completely satisfactory." Tr.
1781. Dr. Woodland stated that they were focusing then on
whether the "original typing of the wells was a true depiction of
the constituents of the wells," which seems clearly to refer to
the issue of whether the use of data on parent wells was a fair
representation of the individual hybridomas in them. Tr. 1698.
Further, he specifically remembered that the data, when he saw
them, were in an "MIT notebook" with "brown covers and ruled
pages" which "look like graph paper." Tr. 1699. 139/ ORI
attacked Dr. Woodland's testimony on the basis that he had been
unable to identify the June subcloning data shown to him in 1990
by an investigator. Cf. ORI FFCL III.E.10; Tr. 1739 (Woodland).
However, by that time, the data were compiled into a completely
different format in the I-1 notebook. 140/ Tellingly, however,
the pages are still identifiable as being graph paper from an MIT
notebook of the kind Dr. Imanishi-Kari referred to as her "spiral
notebook," the brown cover of which is in the record. 141/
Furthermore, the interrelation of the June subcloning results
with other data in the notebooks supports Dr. Imanishi-Kari's
contention that these data did represent the results of that
cloning. Thus, certain clones are marked with red dots on R-
1:31-34 and then a note on R-1:35 explains that the red dots
represent selections for further cloning. Many of these selected
clones are the same ones then described on I-1:124. This
correlation supports testimony that the subcloning was a joint
effort by Dr. Imanishi-Kari and Reis. Tr. 4873 (Imanishi-Kari),
2535-36 (Reis).
The subcloning was triggered, in part, by the puzzling
inconsistency between the results of the assays on the main
fusion and the tests of selected supernatants assayed in the June
6th retest, in which some subclones that had been negative on
BET-1 gave positive results on the retest (and the difference
could not be attributed to sensitivity differences). Tr. 4879-
80. 142/ The further subcloning turned out to produce more
inexplicable results. Thus, Dr. Dahlberg pointed out that, among
subclones out of 16 parent wells from which subcloning was
performed, 12 had subclones producing antibodies showing either
two or three different isotypes. 143/ Since each well was
unlikely to have more than one or two hybridomas (because the
clonality of the wells was estimated, as mentioned above, at 1-
1.5 hybridomas per well), these isotype results seem unlikely.
See ORI Br. 63. However, from the estimation technique, it was
predictable that some of the wells would have two or more clones,
which would explain at least some of the diversity in isotype.
Also, Dr. Imanishi-Kari suggested that many of these strange
results may be explainable today as a result of the later
research mentioned, as well as work showing a lot of reverse
binding by antibodies from transgenic mice, which was not
available in 1985. Tr. 4876-79; Ex. H148; R. Br. 55. In any
case, whether or not these explanations are correct, the
likelihood of fabricating data that on their face appeared
impossible at the time seems remote.
Dr. Dahlberg highlighted the improbability of the diversity of
the subclones derived from the original pauci-clonal wells as
further evidence of the lack of authenticity of these data.
Tr. 346-7; ORI Br. 62-63. However, no suggestion has been
offered why creating these then-inexplicable results could
possibly strengthen either the Cell paper or Dr. Imanishi-Kari's
position in the investigation (since ORI claims the June
subcloning data were created in that process in either 1986 or
1988 for the latter purpose). We find that the inexplicable
nature of the results is, if anything, evidence that it is
unlikely that Dr. Imanishi-Kari would fabricate such results.
Thus, a consideration of the scientific issues and the nature of
the data leads us to conclude that the results are likely to be
what they purport to be, absent clear forensic proof to the
contrary. We turn therefore to the forensic arguments presented
by ORI, first the statistical analysis of the data and then the
document examination of the counter tapes by the Secret Service.
Statistical arguments
ORI's statistical analyses of the June subcloning data and
other data are not evidence from which it is reasonable to
infer fabrication here. In general, ORI's statistical
analyses were flawed.
ORI relied on certain statistical analyses which ORI said were
compelling evidence, entitled to great weight, that the
handwritten counts from the June subcloning data were fabricated
and that other "questioned" data sets were also fabricated. ORI
Br. 72. We discuss these analyses primarily with respect to the
June subcloning data, but the key reasons why we find this
evidence unreliable apply to all of the sets of questioned data
analyzed.
The statistical analyses were performed by Dr. Mosimann, a
statistical expert who was employed by ORI and OSI as a
biostatistician and consultant and who, as a member of the OSI
Scientific Review Panel, interviewed Dr. Imanishi-Kari and other
witnesses during 1990. See, e.g., Exs. H103, H104, H116, H118.
Dr. Mosimann's analyses consisted primarily of two types:
testing whether "low background counts" (defined as counts below
600) "fit" a Poisson distribution mixture model and performing a
uniform digit distribution analysis. Other tests, such as
fitting data to a negative binomial distribution model and using
a "spikiness index" (developed by Dr. Mosimann specifically for
this case) were not independent tests. See, e.g., Tr. 845
(Barron), 1633-34 (McClure), 2219-24, 2244-45, 2247-49 (Speed).
ORI's other statistical expert, Dr. Barron, is an associate
professor at American University, where Dr. Mosimann is an
adjunct professor. Dr. Barron performed only limited analyses,
generally using data and software programs provided by ORI. Tr.
837, 842-45, 1192, 1202-04 (Barron). He confirmed that Dr.
Mosimann's calculations were generally accurate, and the
calculations are not in dispute. Dr. Barron did not, however,
agree with Dr. Mosimann's opinion that the statistical analyses
alone support a conclusion of fabrication; instead, Dr. Barron's
opinion was that the statistical analyses would support a
conclusion that the data were not generated randomly, but were
fabricated, only if the scientific and forensic evidence is
compelling. Compare Tr. 801-02 (Mosimann) with Tr. 830-37, 854,
5019 (Barron).
Moreover, Dr. Barron indicated that the validity of the analyses
depended on the validity of the underlying scientific
assumptions, and he expressed no opinion on the validity of those
assumptions. Tr. 835-36, 1187, 1198, 1212 (Barron). As we
explain below, ORI did not prove that its underlying assumptions
were valid, either through its testimony, through its use of
unquestioned data sets as alleged "controls," or through other
evidence.
Dr. Imanishi-Kari's expert, Dr. Speed, is a professor at the
University of California at Berkeley, and appeared for her
without compensation. He contradicted Dr. Mosimann on the
validity of the assumptions underlying the analyses, on the
validity of some of the techniques, and on the reasonableness of
the inferences drawn from the analyses. Both Dr. Mosimann and
Dr. Speed have considerable experience in applying statistics in
the context of experimental science. Contrary to what ORI
argued, we see no reason to accord Dr. Mosimann's testimony
greater weight based on his experience. (See our note on this
above.) Generally, we found Dr. Speed's testimony to be more
persuasive than Dr. Mosimann's.
To a certain extent, ORI's statistical analyses all flow from
characteristics evident on the face of the June subcloning data
which distinguish these data from the other data selected as
"controls." In this section, we discuss the different
statistical analyses and related evidence in detail and conclude
that there were flaws in the analyses and problems with relying
on the "controls." We emphasize, however, that ORI's conclusions
are premised on treating the handwritten counts in the June
subcloning data as though they purport to be a complete set of
counts transcribed precisely as they appeared on gamma counter
tapes, except for rounding to the nearest tens. This presumption
is unwarranted. Evidence elsewhere in the notebooks indicates
that Dr. Imanishi-Kari was aberrant in her data recording and
rounding patterns, so it is unreasonable to assume that if
transcribing real data, she would have consistently rounded to
tens (and, indeed, two background counts in the handwritten data
end in five, rather than zero, and others may have been rounded
to the nearest hundred). Numbers appear to be missing, moreover,
in a few places for one or two of the æ probes where values are
given for the other reagents. Also, the print is sometimes very
obscure on the counter tapes, so the tapes may have been
More important, Dr. Imanishi-Kari would have no apparent
incentive for transcribing the results precisely, particularly
with respect to the low counts used for most of the statistical
analyses. Dr. Mosimann acknowledged that a researcher recording
values in this type of experiment would be interested in the
relative magnitude of the readings, rather than the precise
values. Tr. 733, 739, 811, 1143. In this particular experiment,
there are marks such as X's or asterisks indicating particular
values, and this suggests that not all of the values were of
interest to her. Other researchers in the laboratory transcribed
counts from tapes without purporting to transcribe precise
values, so Dr. Imanishi-Kari was not unique in this respect. 144/
In other words, there are equally plausible explanations other
than fabrication for why these data do not look like numbers
precisely transcribed from a gamma counter tape.
Thus, even if the statistical analyses were more reliable than we
find them, we would not infer from those analyses alone that the
June subcloning data were fabricated. In light of the evidence
as a whole in this case, the more reasonable inference is that
Dr. Imanishi-Kari was recording real data from a counter tape,
without intending to be exact, rather than that she was
inventing fake values.
We note that we do not consider it suspicious here that the data
in question are handwritten and that the low values might not be
precisely transcribed. Arrows indicating subclones with positive
values are handwritten to the left of the counter tape on these
pages (the column indicating a screen for antibody with a
kappa/lambda probe). The handwritten data in the three
additional columns (labeled BET-1, AF6, and anti-æ) correspond to
the subclones with arrows. It makes sense to interpret the
arrows as indicating which subclones were producing idiotype-
positive antibodies and which therefore were subsequently tested
with the three anti-æ reagents. If only supernatants from the
highlighted subclones were tested with the three æ probes, it
would be reasonable to handwrite the æ results so they would line
up with the kappa/lambda results for those subclones, rather than
cutting and pasting many small pieces of counter tape. 145/
ORI did not establish that the Poisson distribution mixture
model is a valid model, properly applied here.
The first part of ORI's statistical analyses of the June
subcloning data assumes that gamma counter readings under 600
from different wells of a "fusion experiment" are background
counts which should follow a mixture of Poisson distributions.
146/ Based on this assumption, Dr. Mosimann used a test (the
chi- square goodness-of-fit test) to determine probabilities of
whether certain data sets fit Poisson distribution models of up
to nine mixtures. He applied this test to 265 low script counts
of the June subcloning data (on the theory that these were
background counts), low counts from other questioned data, and
low counts from six sets of unquestioned data from notebooks of
Dr. Reis and Dr. Imanishi-Kari (five sets from tapes and one that
is handwritten) that he treated as "controls."
For the following reasons, we conclude that ORI did not prove the
validity of the use of a Poisson distribution mixture model:
ORI relied primarily on evidence showing that it is a well-
settled principle that repeated readings from a single,
constant radioactive source over a period of time will
follow a single Poisson distribution. Tr. 629, 633-36
(Mosimann), 1481 (Gilbert), 2189 (Speed); ORI Report, App.
B, at B-7. While this principle is generally accepted, the
issue here is whether a collection of single readings from
numerous sources (such as the wells on a microliter plate in
a radioimmunoassay) should be expected to follow a mixture
of Poisson distributions. 147/
Contrary to what ORI stated, the Beckman gamma counter
manuals do not state that the counter uses the Poisson
distribution model for counts from multiple sources. ORI
Br. 73, citing Ex. H525, at 41, 51. Rather, the manuals
simply refer to a unique characteristic of the Poisson
distribution: the fact that standard deviation of a Poisson
distribution is the square root of the mean of values in the
distribution. 148/ The user of the gamma counter can thus
estimate the error of a count, the amount by which a single
reading from a sample (as in one well of a microliter plate)
can deviate from the actual, average, counts-per-minute
value of that sample. Ex. H526, at 31; Ex. H525, at 51.
The manuals do not state that low, single counts from the
multiple wells of a microliter plate will follow mixtures of
Poisson distributions.
Dr. Mosimann admitted that he was not aware of any studies
to determine whether readings from the multiple wells on a
microliter plate fit Poisson mixture models. Tr. 5903-04,
5912. While Dr. Mosimann described the Poisson distribution
as quite standard, he was referring to an experiment showing
that multiple readings from a single, constant radioactive
source fit a single Poisson distribution. Tr. 633-36.
Dr. Barron admitted that whether the low counts from the
questioned pages should follow Poisson distributions was a
serious question. Although he had looked in some textbooks
to "see what I could find," he described the mixture version
of the Poisson distribution as "hard to find anywhere" and
he cited no scientific source establishing the validity of
the mixture model. Tr. 1198. ORI referred to a two-mixture
model in statistical literature; Dr. Speed described this
reference as the only example of a Poisson mixture model of
this kind that he has seen in the literature, and stated
that he did not believe that statisticians commonly use
Poisson mixture models as ORI used them in this case. ORI
Br. 73; Tr. 2195.
Dr. Speed testified that there was no compelling scientific
reason why gamma counter readings from different wells
should fit a Poisson mixture model, in contrast to the
strong empirical and scientific reasons why repeated counts
from a single radioactive source should fit a single Poisson
distribution. Tr. 2216-18, 6084-88. We do not find his
testimony to be outweighed by that of ORI's scientific
witnesses. While Dr. Gilbert is a physicist and a Nobel
prize-winning biologist to whose opinion we would ordinarily
give great weight, the testimony elicited by ORI from Dr.
Gilbert about applying the Poisson mixture model to the
assays here did not clearly set out either an empirical or
theoretical basis for his opinion, that directly relates to
the issues here. 149/ Dr. McClure's testimony on this point
was conclusory, without a clear foundation. See, e.g., Tr.
1622-23 (McClure).
The testimony of ORI's witnesses as a whole exhibited
considerable uncertainty about the theoretical underpinnings
for the use of the mixture models. For example, Dr. McClure
testified that mixtures were used because there were three
different assays performed and different reagents used. Tr.
1622-23 (McClure). Dr. Mosimann discussed mixtures in the
context of different readings resulting from different
"cooking" times of different wells on the same plate
containing the same biological preparation. Tr. 738-39
(Mosimann), see also Tr. 1540 (Gilbert). Also, Drs.
Mosimann and Gilbert disagreed over whether non-background
count from multiple sources would be expected to follow
Poisson distributions. Tr. 1132-34 (Mosimann), 1542
(Gilbert).
Dr. Mosimann's conclusion that low counts from certain data sets
from Dr. Reis and Dr. Imanishi-Kari (which ORI called
unquestioned data) "fit" Poisson mixture models of nine or less
mixtures does not establish the validity of the model, for the
following reasons:
Only one of the controls "fit" a Poisson mixture model with
a chi-quare probability greater than 50% (specifically,
50.7%), and the others had chi-square probability values
less than 20% (including two which had chi-square values
less than 5%, although these sets were later found to fit
mixture models through computer simulations). Exs. H413,
H414, H754, H806; Tr. 5671 (Mosimann); ORI letter enclosing
statistical tables supporting Exs. H413-H414, September 28,
1995. While chi-square probabilities greater than 5% were
sufficient so that Dr. Mosimann's definition of "fit" would
apply, ORI did not show that a statistician would ordinarily
conclude from these probability values that the underlying
model was valid. 150/ See, e.g., Tr. 6004-06 (Speed).
Historical controls such as those used here are generally
not as trustworthy as independent contemporaneous controls.
Tr. 6006-10 (Speed). Also, control data sets should be
comparable data sets in order to be valid controls. Tr.
1199-1201 (Barron). Each of the "controls" here is data
from a gamma counter reading of a radioimmunoassay, as the
June subcloning data purports to be. Only one of the
controls is transcribed from a tape, however, and that
transcription purports to be an exact transcription, with no
rounding at all. R-2:114-124. Some of the controls would
have involved fewer preparations and reagents than the June
subcloning assays; if we adopt ORI's various theories of
reasons to expect Poisson mixtures, this would suggest that
these control data sets would more likely fit a mixture
model of less than nine mixtures than the June subcloning
data, even assuming the mixture model is reliable generally.
Dr. Mosimann provided no scientific explanation for why he
selected particular data sets for controls. With respect to
a different analysis, he indicated he chose "fusion
experiments" from the same period and same laboratory. Tr.
717-18. The controls here, however, include two assays on
mouse sera, rather than supernatants from fusion products.
I-1:48-58; R-2:114-124. Also, the record includes other
unquestioned data sets for assays of fusion products for
which no Poisson mixture analysis was presented to us (such
as Dr. Weaver's data used as a control for different
statistical analyses). Ex. H402. ORI did not explain why
analyses of these data sets using the Poisson distribution
mixture model were not presented to us.
Even assuming that low counts from different wells in all
radioimmunoassays should follow Poisson mixture models, we would
not find ORI's analyses reliable as a basis for inferring
fabrication. Dr. Speed's testimony, which we found convincing,
raised other significant questions about the reliability of ORI's
analyses.
Dr. Speed testified that a significant amount of subjective
judgment is involved in determining how to "bin" data to perform
the chi-square goodness-of-fit test used by Dr. Mosimann and in
deciding how many mixtures of Poissons to use. Tr. 2193-94,
2205-12. ORI did not rebut this testimony directly, but defended
the reasonableness of Dr. Mosimann's judgments, in part with
testimony from Dr. Barron. Tr. 5033-37 (Barron). Dr. Barron
also testified, however, that selection of bins is "to some
extent . . . arbitrary" and that he could not be sure he would
have made the same choices as Dr. Mosimann. Tr. 1182-83, see
also Tr. 5657 (Mosimann). Dr. Barron also said that one of the
difficult problems is knowing how many mixtures to use in the
model and that, while Dr. Mosimann tried to fit the data to
possible mixtures from one to nine successively, the reason Dr.
Mosimann did not try more than nine mixtures was because of
computer limitations. Tr. 1189-90. ORI did not establish that
using only nine mixtures or less was scientifically appropriate
in this case.
Even assuming the judgments made here were reasonable, however,
the record indicates that a different exercise of reasonable
judgment may have given different results. Dr. Mosimann defended
the judgment to "bin" the data by tens because most of the low
counts appeared to have been rounded to tens. Tr. 1233-34.
Dr. Speed said this binning was inconsistent with the general
rule that numbers must be binned so that there is a minimum
expectation of five values in each bin, and that even a variant
of the rule cited by ORI (80% of the bins should be greater than
or equal to five values and all should have at least one value)
was violated with respect to nine out of ten data sets analyzed
by Dr. Mosimann. 151/ Tr. 2334, 2939-40; Ex. H414. Dr. Speed
presented evidence that if the rule were followed and bins of 30
were used instead, one of the questioned data sets would fit the
Poisson distribution model. Tr. 2207-10; Ex. R59. In rebuttal,
Dr. Mosimann (1) asserted that it is not always necessary to
follow the rule of 5 and argued that applying the rule of 5 here
lessened the effectiveness of the chi-square test; (2) provided
evidence of computer simulations to overcome the problems the
rule was intended to address; and (3) questioned Dr. Speed's use
of bins of 30. Tr. 1226-29, 5657-60, 5671-80, 5900-02; Exs.
H414, H754, H806. This rebuttal was not as persuasive as Dr.
Speed's response. More important, it did not effectively
undercut the reasonableness of following the general rule and
binning at 30, to achieve a minimum expectation of five.
Moreover, with respect to two control sets, the computer
simulations reached results different from the chi-square
analyses. The fact that different reasonable analyses can reach
different results raises substantial questions about relying on
such analyses to establish fabrication of data. 152/
Dr. Mosimann tried to buttress the chi-square analysis of whether
the June subcloning data fit to Poisson mixture models by
examining whether these data "fit" a negative binomial model, by
developing a "spikiness index," and, later, by his computer
simulations. None of the additional tests performed goes to the
validity of the underlying assumptions.
Dr. Mosimann's rationale for using the negative binomial was not
any independent basis for believing that the data should "fit"
the negative binomial model. Rather, it was based merely on the
fact that the negative binomial is related to the Poisson
distribution. Thus, we find that it is not an independent test
and is based on the same questionable assumptions as the Poisson
mixture model. We also note the following about the negative
binomial model:
Dr. Speed testified that there is no scientific reason to
think that the data here should fit a negative binomial
model. Tr. 5998.
While ORI's witnesses suggested that data with any number of
Poisson mixtures should fit the negative binomial, Dr.
Speed's testimony was that use of this model was not
equivalent to testing the June subcloning data against
possible mixtures with more than nine components. Tr. 759,
1139-41 (Mosimann), 1189-90 (Barron), 5996-6000 (Speed).
Indeed, ORI's own analysis would belie such a conclusion
since one of the unquestioned data sets (R-2:114-124) fit a
Poisson mixture, but not the negative binomial. Ex. H414.
Dr. Mosimann's own testimony raises questions about his use
of the negative binomial model. He characterized the
Poisson mixture models as multimodal, and criticized Dr.
Speed's use of larger "bins" in analyzing the data on the
grounds that it could cause a multimodal distribution to
become unimodal. Tr. 5656-60. He described the resulting
unimodal distribution as not descriptive of the process
going on in the microliter plates. Tr. 5900-02. However,
he also testified that the negative binomial distribution is
unimodal. Tr. 5812.
On the whole, we consider the negative binomial analyses an
unsuccessful attempt to compensate for the problem that ORI's
computer could generate Poisson distributions only up to nine
mixtures. ORI thus did not effectively rule out the possibility
that Dr. Imanishi-Kari's data would fit a Poisson distribution
model of more than nine mixtures.
Similarly, Dr. Mosimann in effect acknowledged that he used the
spikiness test because he was concerned with certain aspects of
the use of the chi-square goodness-of-fit test (which gives
credence to Dr. Speed's concerns). Tr. 766, 1232, 5668, see also
2341 (Speed). Dr. Mosimann's "spikiness index" measures the
exposed "sides" or "walls" in a histogram of values such as gamma
counter readings; a graph with marked, separated peaks and
valleys will have a higher relative spikiness index than one with
a flatter, more even distribution of values. Tr. 748-53
(Mosimann). Dr. Mosimann reported that the questioned data
exhibited spikiness greater than either the unquestioned data or
simulated data based on Poisson mixture and negative binomial
models. Tr. 767-71; Ex. H416.
The spikiness test is a untested method invented specifically for
this case, not a commonly accepted statistical technique. Dr.
Barron said that he considered spikiness an "interesting"
statistic and "an imaginative, reasonable way of getting around
the notion that the arbitrariness of the chi-square test might
lend some criticism" to Dr. Mosimann's work. Tr. 1190. Dr.
Barron said that he had not heard the term "spikiness" until he
read the ORI Report and that the spikiness test was not a
standard statistical test. Tr. 843-44, 1181. In any event, as
Dr. Speed noted, the spikiness index merely quantifies a feature
evident from graphs of the June subcloning data.
The computer simulations, moreover, do not compensate for basic
flaws in applying the Poisson mixture model to the June
subcloning data. The simulations do not establish the underlying
assumptions. Moreover, the simulations were based on using a
five-mixture model for these data, which Dr. Mosimann had chosen
as the closest fit to the June subcloning data based on his chi-
square results, which, as discussed above, involved considerable
subjective judgment. Exs. H754, H806.
ORI's uniform digit distribution analysis is not evidence
from which we would infer fabrication.
The second set of analyses that Dr. Mosimann performed on the
June subcloning data was called "uniform digit analysis" or
"uniform digit distribution analysis." This analysis assumes
that randomly generated digits will follow a discrete uniform
distribution. Studies co-authored by Dr. Mosimann found that
people trying to generate three-digit lottery numbers that would
look as though they were randomly generated could not effectively
do so, because their numbers reflected a digit preference. For
this case, Dr. Mosimann analyzed the frequency of the appearance
of digits from 1-9 in the June subcloning data (high and low
counts) and in the "control" data, and determined that, unlike
digits from the control data, digits from the June subcloning
data did not fit the uniform digit distribution model. He
concluded that the June subcloning data were fabricated because
they showed a preference for digits 1, 3, 7, and 8 (although
another of Dr. Imanishi-Kari's handwritten data sets showed
different preferences). Exs. H409, H410, H411.
While ORI presented this analysis as a commonly accepted
statistical technique for determining fabrication of data, the
statistical authorities referred to in the record do not support
this conclusion, for the following reasons:
These authorities support only a conclusion that a departure
from uniformity, in many cases, indicates a personal
preference for digits and therefore some form of human
intervention. Ex. H200, at 3. As we discussed above, the
handwritten counts in the June subcloning data do not
purport to be data with no human intervention, and we do not
find from the circumstances here that the obvious human
intervention makes it more probable than not that the data
were fabricated.
These authorities, as described in Dr. Mosimann's own
article, are based on an expectation of uniformity in what
are referred to interchangeably as "terminal" or "error" or
"rightmost" digits that do not contain any information. Ex.
H200; Tr. 1141-43 (Mosimann). The analyses performed here,
however, were not on the rightmost digits, but were on the
rightmost digits that were not a zero and that were not the
leftmost digit. H636, H637, H638; Tr. 784-85 (Mosimann).
ORI presented no evidence that analysis of these digits (as
opposed to "rightmost" digits) is a commonly accepted
statistical technique.
The previous analyses by authors other than Dr. Mosimann are
described as analyzing digits that do not contain
information. The judgments made here about what digits were
not significant digits (that is, which digits did not
contain information) are questionable, since this analysis,
for example, would consider the 8 in 800 to be significant,
but not the 7 in 27,000. See, e.g., Tr. 786 (Mosimann),
2234 (Speed).
ORI did not provide testimony from Dr. Barron, ORI's other
statistical expert, to support a conclusion that the
particular analyses used by Dr. Mosimann were a commonly
accepted statistical technique for determining fabrication
of data. Instead, Dr. Barron testified that he would not
infer fabrication from the statistical tests used here
unless there was other compelling evidence. Tr. 830, 5019.
ORI's reliance on "control" data sets here is also misplaced,
since most of those sets are data directly from counter tapes
which do not contain transcribed or rounded numbers, as the June
subcloning data do. Ex. H420. Dr. Mosimann tried to overcome
the rounding problem by first subjecting the data to a rounding
protocol. The record shows, however, that this rounding protocol
does not in fact mimic Dr. Imanishi-Kari's rounding behavior, as
shown by a set of data which are handwritten, but for which the
counter tape is also available (I-1:20-21; I-1:12-19). 153/ Tr.
2226-30 (Speed); Exs. H419, R61. Dr. Mosimann's assertion that
the computer rounding protocol was not intended to emulate
Dr. Imanishi-Kari's rounding behavior exactly and was not, for
example, concerned with whether she rounded up or down, was not
consistent with his testimony that the effects of the computer
rounding protocol were quite consistent with Dr. Imanishi-Kari's
known rounding behavior. Tr. 1125, 5694.
In sum, there are some questions about the uniform digit analysis
as applied here, but, even accepting this technique as valid, we
would not infer from this analysis alone that the questioned data
are fabricated. These statistical analyses fail to show that the
handwritten data were the result of intentional fabrication
rather than idiosyncratic behavior in recording or rounding data
where the digits studied were admittedly of little scientific
significance.
The Panel concludes that the statistical analyses are not
reliable evidence that the June subcloning data or other
questioned data were created by fabrication or falsification as
alleged by ORI.
Document examination arguments
ORI's only document examination attack on the June subcloning is
related to the green counter tapes on the left-hand side of the
pages (except I-1:124A and 128A which have no tapes). 154/ The
Secret Service found no match for the printer ribbon ink with
tapes from dates around those on the pages in the I-2 notebook
which they believed came from the same printer. 155/ On the
other hand, the Secret Service found a "full match" between these
tapes and tapes derived from a Maplethorpe "notebook" with dates
between November 26, 1981 and April 19, 1982 (as well as with the
green tape at I-1:103 discussed in relation to the January fusion
below). ORI Br. 63; Exs. H501, at 2, H502, at 3, H503.
Fabrication would have been more likely as an explanation
for the green tapes in the June subcloning if such tapes did
not appear in other researchers' notebooks until 1986 or
later rather than gradually disappearing much earlier.
ORI's argument that tapes containing part of the June subcloning
data were probably from before 1985 and most likely as old as
1981 or 1982 is less than persuasive. Obviously, it would be
much more probative of fabrication of data purporting to be from
mid-1985 if ORI had shown that such tapes did not become
available until after the experiments were supposed to have
occurred. 156/
ORI had two different possible scenarios for the timing of the
alleged fabrication of these pages. One theory was that
fabrication might have occurred in 1988. This was based on the
fact that the question of whether the Table 2 hybridomas had been
subcloned was raised during the first day of a 1988 interview of
Dr. Imanishi-Kari by NIH representatives in Boston and the June
subcloning data were produced the next day. ORI Br. 62 and n.43.
A second theory was that the fabrication occurred in 1986 to deal
with Dr. O'Toole's charges when meeting with Dr. Wortis (although
ORI suggested that this was less likely because Dr. O'Toole was
not shown the June subcloning data then). Id. at 23-24, 62,
n.43. In either case, ORI argued that Dr. Imanishi-Kari
fabricated the June subcloning (and the January fusion experiment
discussed later) "from green tapes she had lying around" and
looked for "tapes with numerical values that she could use, in
the process paying no attention to the color of the tapes or the
numerical interrelationship of the numbers within the tapes."
ORI Reply Br. 20. Then, she "made up" the handwritten numbers in
the June subcloning data "probably from scratch." Id. This
description which ORI called "straightforward" does not explain
why Dr. Imanishi-Kari would not simply write down all the
"numerical values that she could use" instead of allegedly doing
so for some assays and then searching for tapes to construct
others. Cf. ORI Reply Br. 20. Nor does it address the somewhat
peculiar result that what allegedly came to hand in such a search
for tapes undertaken in 1988 (or even 1986) were so many tapes of
a color allegedly not available after 1984.
It was not disputed that Dr. Imanishi-Kari stored loose counter
tapes, pages, and folders in piles around the laboratory and
office, on desks and window sills. It was, of course, not
impossible that she would find tapes five or more years old among
this assortment. 157/ However, there was no testimony that
subclonings and fusions did not occur in her laboratory during
the intervening years, so that tapes useable to show fusion
results from much more recent times were probably available, if
she had been attempting to find tapes to use for this purpose.
158/
The so-called "full match" with counter tapes from 1981 or
1982 is meaningless.
The finding of a "full match" projects a misleading confidence
that a clear connection exists between the questioned tapes and
the "match" tapes and that the possibility of other, more timely
matches has been excluded. Neither proved to be the case,
however.
The "full match" finding does not prove any definite link between
the June subcloning tapes and the older tapes. The fact that a
"full match" is supposedly made to tapes covering as wide a time
span as six months evidences that this matching process does not
yield any precise information about dating. 159/ ORI stated that
this imprecision was not "surprising, particularly given the
testimony . . . that supplies are bought in bulk, and batches of
a particular kind of supply typically will have the same or
similar composition. . . . Thus, one would expect the same ink
formula to show up throughout a particular batch of ribbons,
while tapes from the same production run would appear to be very
similar." ORI Reply Br. 16-17. Hence, ORI stated, "recurrent
matches" over a "fairly extended period" could occur because "the
ink, tape, and font variables would stay the same over a long
period, and, necessarily ink intensity would match on a recurring
basis." ORI Reply Br. 17. However, if the same batch of ribbons
and rolls of green tape could be used recurrently over 21 months,
there is no basis to doubt that ribbons with the same ink formula
and full or partial rolls of green tape might recur over the
succeeding months. 160/ ORI acknowledged that at most the
evidence on matches "identifies the era" when the tape might have
been generated, but relied mainly on finding no contemporaneous
matches as evidence of fabrication. ORI Reply Br. 17.
The absence of a "contemporaneous match" is not probative
because most of the tapes from the contemporaneous period
were not available to be tested and the dating of the June
subcloning is not precise enough to make the comparison that
was tested meaningful.
The evidence on the absence of a match to contemporaneous tapes
is also unpersuasive, however. Mr. Stewart's conclusion that the
tapes from I-2 demonstrated that the I-1:124-128 tapes could not
have come from the same time period (June 1985) depended entirely
on both sets of counter tape having been generated using the same
printer (not merely the same type of counter). This assumption
was based on tapes showing characteristics of "what I'm calling
the same printer, like the same font and I have no evidence that
there was an additional printer that would produce a font like
that." Tr. 4155 (Stewart). This assumption was unwarranted,
however, as discussed in detail elsewhere. While Dr. Imanishi-
Kari may well have used only two counters from her laboratory in
generating most of the data in I-1, it does not follow that
printers were never substituted that had similar fonts, nor does
it follow that tapes in notebooks other than I-1 were generated
only by those two counters. (Dr. Imanishi-Kari stated that she
sometimes used other counters and that counters were available on
the second, third and fifth floors of the same building. Ex.
H101, at 53.)
In assessing the significance of not finding a "contemporaneous
match," the points discussed elsewhere about the limited set of
tapes available to search for a match and the limitations of the
search conducted are even more important. First, as discussed
above, even had all the tapes in all the notebooks been tested by
ink analysis, it is unlikely that most of the tapes generated
during the relevant time frame were retained to begin with, and,
of those retained by researchers, most were probably not
available through MIT in 1989. Second, the existence of ink
matches from the general time frame of the June subcloning
experiments was not excluded; we have no evidence that all other
existing tapes generated at the relevant time were compared. In
searching for a match, the Secret Service did not test all the
tapes in all the more than 60 notebooks presently in the record,
but rather looked first at yellow tapes in the I-2 notebook from
dates that narrowly framed the dates on I-1:124-128. Finding
that the ink on those tapes was not a match to that on the green
tapes on I-1:124-128, the examiners "as an afterthought" tested
green tapes 161/ in the 26 which it had obtained when the ink
analysis tests were conducted looking for a match. Tr. 3775,
4015-17 (Stewart).
Dr. Imanishi-Kari argued persuasively that the actual tapes in
the June subcloning were probably generated after the dates (June
20-22) on the pages. Specifically, she testified that these
dates were probably when the supernatants were collected, since
subcloning could not begin until 10-14 days after the June 6th
retest, and the size of the assay indicated the experiment
results would not be produced for some time after that. R. Br.
56-57; Tr. 5268-69. It is thus possible that the tapes were
generated for the June subcloning after the I-2 tapes either with
a change of ribbon and (for a short time) paper or using a
substitute printer with its own ribbon and paper. Also,
attributing significance to the failure of tapes dated in June in
the I-2 to match the June subcloning dates requires an
assumption, that the dates in the I-2 notebook were precise, for
which no evidence was presented.
Mr. Stewart testified that the examiners later looked through the
additional notebooks, but did not find any green tapes subsequent
to January 1984. Tr. 3811. He did not indicate whether any
additional yellow tapes from June, July or August 1985 (besides
those in I-2) were found in those notebooks or tested to
determine if they might have had the same ink used in the same
printer (based on font).
Thus, it is possible that other tapes with matching ink formulas
produced on the same printer existed but were not found. It is
also possible that the use of a substitute printer could account
for the failure of the June subcloning tapes to match yellow
tapes from nearby dates. As mentioned, a back-up printer was
used during down time three or four times a year, according to
Mr. DeHaro who was responsible for connecting it. Tr. 4450-52.
It is possible that the substitute printer continued to use a
roll of green tape after most of the tape had been used up from
the main stores and such a substitute would obviously have had a
different ribbon which could have had a different ink formula
from that in the regular printer.
ORI rejected this scenario because a match was also found between
the ink formula in the June subcloning green tapes and one of the
green tapes used in the January fusion experiment discussed in
the next section. ORI argued that to account for these matches
(and the finding that the ink formula on other green tapes in the
January fusion experiment does not match these tapes) would
require "not one, but two, printers sitting in the basement," of
which "Printer 1" was used to generate one set of January fusion
green tapes and then broke down and was replaced by "Printer 2"
to generate the other January fusion green tapes which then broke
immediately, since it was used only for that part of the January
fusion tapes. Then, in June 1985, Printer 2 is brought back up
to generate the June subcloning tapes. Neither is otherwise used
again, at least with the same green tape. See ORI Br. 90-91.
162/ ORI calls this scenario "preposterous," but it is also
entirely overstated. What is required is only that a substitute
printer with green tape was used in the January fusion and the
ribbon changed in the midst of that experiment and then used
again in the June subcloning with a ribbon whose ink matches one
but not the other of the January tapes (by that time it may or
may not have been the same ribbon). 163/
The convergence of less common tape color between two questioned
experiments and the divergence of ribbon ink formula within one
of those experiments is certainly peculiar, but the theory that
Dr. Imanishi-Kari created this circumstance by using only old
green tapes to fabricate the two experiments would also be
peculiar. ORI calls this the "one simple explanation that
accounts for all of the evidence," but in fact fabrication
requires an equally odd set of coincidences and motivations,
e.g., in Dr. Imanishi-Kari's finding these unusual tapes to use,
unnecessarily creating bizarre anomalies in the data which could
have been tailored instead to what was needed to support her
position (in the case of the June subcloning results), and using
tapes from several sources to create an elaborate and interlinked
experiment used for nothing else, just to lend verisimilitude to
a few negative normal results on unquestioned tapes that could
have simply been presented as a separate normal experiment (in
the case of the January fusion). ORI Br. 91.
In light of all the other evidence making fabrication unlikely,
we find that the forensic evidence is not sufficiently persuasive
to demonstrate that the June subcloning tapes are more likely
than not the product of intentional fabrication.
For the reasons explained above, and considering all the relevant
evidence, we conclude that ORI did not prove charges two and
three, Table 2, by a preponderance of the evidence.
3. Data on normal hybridomas; January fusion
Table 2, charges four and five: ORI charged that the normal
control mouse data reported in Table 2 were "deliberately
falsified and fabricated in part" which constituted scientific
misconduct. Charge letter 5. In addition, ORI charged that
Dr. Imanishi-Kari committed scientific misconduct by fabricating
"experimental data reported at I-1:101-109" and submitting those
data to "PHS investigators as support for the results reported in
Table 2." Id.
Issues: In addition to presenting frequency data on transgenic
hybridomas, Table 2 compares those results to figures for spleen
and lymph node hybridomas from normal mice. 164/ The very low
idiotype positivity figures (1/144 and 0/100 respectively) shown
for the normal hybridomas were important in that they provided
assurance that the results for the transgenic hybridomas
represented a meaningful phenomenon. According to
Dr. Imanishi-Kari and Dr. Reis, the normal data were derived from
two separate experiments currently located at R-1:76-80 and I-
1:106-107 (after the original mouse used as a control for the
Table 2 experiments proved to be mistyped as a normal mouse when
in fact it was transgenic). 165/ Tr. 4847-48 (Imanishi-Kari),
2546 (Reis). ORI challenged both sets of data. In relation to
R-1:76-80, ORI argued that the assay was actually run on a
different idiotype reagent than that reported in the Cell paper
and that the reagents were not interchangeable. In addition, ORI
pointed out that the raw data at R-1:76-80 showed 12 unreported
results above the cut-off. Dr. Imanishi-Kari testified that, as
she later noted on the page, these results were discarded because
they were false positives caused by preexisting radioactivity in
the counting tubes ("tube counts"). Tr. 4851. ORI also alleged
that the results reported for allotype (i.e., that none of the
normal hybridomas were positive for either æa or æb) were false
because there was no record of testing the normal hybridomas by
allotype. ORI Br. 81. In relation to I-1:101-109, the bulk of
the evidence of fabrication related to the transgenic fusions
(which were not published) based on statistical and document
examination arguments, but ORI inferred that the related normal
data at I-1:106-107 must also be fabricated by association, and
also presented some arguments in relation to the normal data
pages. All of these arguments are discussed together in the
section dealing with the January fusion data.
Analysis: We first address whether the normal control data at
R-1:76-80 were deliberately falsified or fabricated in Table 2.
Next, we turn to whether the data called the January fusion,
I-1:106-07, were fabricated as part of the support for the normal
control data in Table 2.
One of the initial triggers for Dr. O'Toole's concerns was the
discovery in the 17 pages of the results for the "normal" control
mouse. This concern was satisfactorily addressed because
Dr. Imanishi-Kari showed that the mouse had been proved (after
molecular analysis) to have been a mistyped transgenic and this
explained why it had levels of idiotype-positivity similar to
other transgenic mice. See Tr. 203-04, 301 (Dahlberg); I-1:133.
While apparently accepting the evidence of mistyping, ORI
continued to argue that normal mice might show higher levels of
idiotype-positive antibodies than the authors represented and
that the difference might be significant in light of findings
suggesting that the reported level of idiotype-positive
endogenous antibodies in transgenics was overstated. Narrowing
the gap between the transgenics and the normals from both
directions might undercut the Cell paper's conclusions.
Dr. Imanishi-Kari testified that the source for the normal data
to replace those discarded because of the mistyping was normal
data from two other experiments: R-1:76-80 and I-1:106-07
(January fusion). Tr. 4847-48. Dr. Imanishi-Kari previously
stated that Dr. Reis constructed Table 2 earlier in 1985 in
preparation for a talk (before the Cell paper was drafted) and
that Dr. Reis "was the one actually who collected data for
table 2 . . . [a]nd she went over the data that was in my
file . . . and that was the data she took to put in this
table 2." Ex. H103, at 112; see also Tr. 2666 (Reis). This
account is supported by the testimony of Dr. Reis that she
incorporated the data from the two sources and by a notation on
R-1:76 in Dr. Reis' handwriting totaling results from both
sources. Tr. 2546-47; see also Tr. 4848 (Imanishi-Kari). Dr.
Reis wrote these totals before she left the laboratory in January
1986 and returned to Brazil. Tr. 2502-03, 2520, 2545-47 (Reis),
4848 (Imanishi-Kari). ORI attacked both sets of normal data as
falsified or fabricated.
ORI did not prove that the normal data at R-1:76-80 were
intentionally falsified as to the anti-idiotype reagent.
ORI challenged the data from R-1:76-80 on the grounds that the
Cell paper said that the only anti-idiotype reagent used was an
anti-17.2.25 guinea pig antibody reagent. Cell paper 257. ORI
argued that a different anti-idiotype reagent was actually used
in the assay at R-1:76-80, and the experimental record then
altered to misrepresent this. ORI Br. 76. There is no question
that the entry after "anti-idiotype coat" on R-1:76 has been
changed and the notation "GP [guinea pig] anti-17.2.25" entered
in Dr. Imanishi-Kari's handwriting. R. Br. 58. The question is
whether ORI proved that the change represented a deliberate and
intentional effort by Dr. Imanishi-Kari to falsify the coating
reagent used in the published normal data. We conclude that ORI
did not, for the following reasons.
The Secret Service used infrared technology to produce a blow-up
of the writing under "GP anti-17.2.25" in an effort to determine
what was originally written in that space. No previous entry was
legible, and Dr. Dahlberg acknowledged that the images do not
look consistent with ORI's theory that the rabbit reagent was
previously listed there. Ex. H549; Tr. 367-68 (Dahlberg). In
fact, he testified that the altered entry might not have been a
coating designation at all, since Dr. Reis tended to put her
reagent notations at the end of experiments, and might well have
been "an entirely different irrelevant notation that was replaced
with the guinea pig anti-id coat." Tr. 368-69. 166/
Although the original entry could not be discerned, ORI argued
that it must have been rabbit anti-124/40, because that anti-
idiotype reagent was used in other experiments in the laboratory
including transgenic fusion assays at R-1:70-75. ORI suggested
that these assays constituted the "transgenic portion" of the
same experiment so that it would be surprising to have different
coating reagents used. ORI Br. 77-78; Tr. 1363-64 (Davie);
compare R-1:73 and 75 with R-1:76. Dr. Imanishi-Kari denied that
the assays at R-1:70-75 were part of the same experiment as the
assays at R-1:76-80. R. Br. 59, n.70. We found that the R-1:70-
75 assays related to transgenic and normal mice immunized with a
different antigen (chicken gammaglobulin or CG) from that used in
the idiotype system involved in the Cell paper (NIP). Accord Tr.
2542-43 (Reis). By contrast, the assays at R-1:76-80 related to
an unimmunized mouse. Tr. 2544 (Reis).
Dr. Imanishi-Kari argued that, even assuming that the coat was
altered from rabbit anti-124/40 to guinea pig anti-17.2.25, the
change was simply a correction. R. Br. 57-59. Both Dr. Reis and
Dr. Imanishi-Kari testified that they went over Dr. Reis's
results almost daily, and that Dr. Imanishi-Kari would commonly
write in corrections and observations. Tr. 2553-54, 2602 (Reis),
4849 (Imanishi-Kari). Dr. Imanishi-Kari argued, and Dr. Wortis
agreed, that the corrected coating was more scientifically
credible in light of the results on the controls which showed
reactivity almost twice as great with the 17.2.25 antigen as with
P5.40.3 (the antigen to 124/40). 167/ R. Br. 57-59; Tr. 2778
(Wortis), 4850 (Imanishi-Kari).
Dr. Imanishi-Kari argued that, for the purposes for which she
used the two idiotype reagents, they could be substituted without
any substantive effect on the results of the assays. R. Br. 64-
65, n.79. Consequently, she contended that she would have no
reason to alter the coating reagent, since it would make little
difference which one was actually used. ORI presented a great
deal of testimony to the effect that the two reagents were not
identical and could be expected to have differing patterns of
reactivity. See, e.g., Tr. 249, 371-72 (Dahlberg), 1343-45
(Davie). However, Dr. Imanishi-Kari did not claim that they were
not different but that both reacted strongly to the idiotype and
thus could identify idiotype-positivity effectively. R. Br. 64-
65, n.79. 168/ ORI argued that this position was inconsistent
with the claim that the very high counts recorded for the 17.2.25
control protein in the assay confirmed the coating reagent as
guinea pig anti-17.2.25 rather than rabbit anti-124/40. ORI
Reply Br. 31. However, Dr. Imanishi-Kari's point with regard to
the controls at R-1:76 was not that the absolute counts for
17.2.25 was very high but that the 17.2.25 control elicited the
strongest reaction, whereas rabbit anti-124/40 would be expected
to give its strongest reaction to its own antigen protein.
Whether the interchangeable use of two anti-idiotype reagents was
a good practice scientifically or was based on sufficient
demonstration of comparable specificities, it is clear on the
record before us that Dr. Imanishi-Kari's laboratory used both
reagents frequently and may have interchanged them
unintentionally at times. For example, ORI agreed that
Dr. Imanishi-Kari and Dr. Reis used the rabbit anti-124/40 as a
"proxy" for the guinea pig anti-17.2.25, citing as an example I-
1:12-21 where the rabbit reagent was noted in the heading to the
experiment but the data were summarized as on VH 17.2.25. ORI
Br. 78, n.55. Dr. Dahlberg testified that many examples could be
found in the notebooks of use of one idiotype reagent in one
assay and the other in the next, which supports the
interpretation that the laboratory did treat the two as
interchangeable (or that great care was not always taken in
specifying which was used). Tr. 93. Even if we found that any
of the experiments published in the Cell paper definitely used
the rabbit anti-124/40, we would not find that ORI proved that
the failure to disclose that a second anti-idiotype reagent was
used was anything more than honest error. 169/ The strong
evidence that both could be used to identify idiotype-positivity
(even though their reaction to particular determinants differed)
and the absence of any persuasive demonstration that the use of
the rabbit anti-124/40 would have significantly altered the
interpretation of the data in the Cell paper make it unlikely
that the omission reflected any intention to mislead readers and
also make it unlikely that Dr. Imanishi-Kari intentionally
tampered with the coating reagent notation on R-1:76 to disguise
the use of rabbit anti-124/40 in one particular instance.
The Panel concludes that ORI did not prove that the anti-idiotype
reagent was intentionally misrepresented in relation to the
normal control data in Table 2.
ORI did not prove that Dr. Imanishi-Kari intentionally
misrepresented the true number of idiotype-positive normal
hybridomas.
Table 2 reports only one idiotype-positive result among the
normal hybridomas, but 12 additional counts over the cut-off
level of 1000 appear among the normal spleen hybridoma results on
R-1:76-80. Dr. Imanishi-Kari testified that Dr. Reis informed
her that the other positive results turned out to be the result
of contamination of the tubes by radioactivity. R Br. 52; Tr.
4850-52, 5093-94 (Imanishi-Kari). When questions arose,
Dr. Imanishi-Kari added a note to R-1:80 explaining that
"according to Moema [Reis] only no. 68 turned out to be real
positive. The others were tube counts." Since Dr. Reis put
Table 2 together, with Dr. Imanishi-Kari reviewing it, the
inclusion of only one positive in Table 2 evidences that Dr. Reis
(who had done the actual experiments on these hybridomas)
believed that the others were not real positives. Cf. Tr. 4688.
ORI did not show any reason that Dr. Imanishi-Kari could not
reasonably rely on Dr. Reis's interpretation of these results.
On the contrary, Dr. Imanishi-Kari's experience with normal
hybridomas in other fusions gave her a reasonable basis to expect
a very low rate of idiotype-positivity and hence to find the tube
count explanation credible.
Furthermore, it is undisputed that Dr. Reis wrote the totals in
the notebook showing only one positive result from this normal
fusion before she left the laboratory in January 1986. In order
to believe that Dr. Imanishi-Kari was making a "spurious" claim
of tube counts, we would have to conclude that Dr. Reis conspired
with Dr. Imanishi-Kari months before any questions were raised
about the Cell paper to disregard results which she knew were
true positives. See R-1:80. We do not find this plausible,
especially in light of the relatively slight effect that
reporting them as positive would have had (i.e., raising the
number of idiotype-positive normal hybridomas from 1/244 to
13/244). We find it more likely that the contamination occurred
as Dr. Imanishi-Kari noted, or at least that Dr. Reis believed
that it had, especially since several witnesses corroborated that
such tube counts occur frequently in the laboratory. See Tr.
4582-83 (Igras), Tr. 3118-19 (Marrack) (always caused by
"somebody else's graduate student"); cf. Tr. 376 (Dahlberg)
(admitted tube counts do happen, although alleged it was "very
rare"). Our conclusion is further supported because ORI did not
point to any scientific research suggesting that the results
which Dr. Reis reported were not consistent with the very low
level of idiotype-positive antibodies generally found in tests of
normal hybridomas. Ex. H230, at 2.
ORI alleged that the claim that all but one of the positive
readings for the normal hybridomas at R-1:76-80 was due to tube
counts was inconsistent with the absence of any evidence that the
transgenic results in R-1:71-75 were retested for tube counts.
As noted above, the assays on those pages are not a transgenic
portion of the same experiment, so the conditions resulting in
tube counts in the normal unimmunized assay may not have applied.
Dr. Reis testified that they did not feel it necessary to check
the transgenic results because the transgenics had been
prescreened, so that only those which had positive scores on two
screens were counted as positive. Since it would be "quite
impossible that you have by chance" a tube count problem twice
independently causing false positives for the same samples, they
did not retest the transgenics again. Tr. 2550. Her testimony
was ambiguous as to which transgenic fusion she was referencing,
but, in context, appears to refer to why they were not concerned
about tube counts in the transgenic portion of Table 2, the data
for which were at R-1:31-34 (and which she proceeded to explain
was a rescreen). Tr. 2550, 2612-14 (Reis). As noted, it does
not appear that the transgenic fusions at R-1:71-75 are part of
the same experiment as the normal fusion at R-1:76-80.
The Panel concludes that it is more likely than not that
Dr. Imanishi-Kari reported what she believed to be the real
number of idiotype-positive normal hybridomas and did not
intentionally misrepresent them.
ORI did not prove that the reporting of negative allotype
results for the normal hybridomas in Table 2 was an
intentional misrepresentation.
ORI argued in its brief that Table 2 presented intentionally
falsified data in another respect. In addition to indicating the
total number of idiotype-positive hybridomas, Table 2 presented
the total number of hybridomas of each category (normal and
transgenic spleen and lymph node) that were idiotype positive
"plus" positive for æa or æb (allotypes). No positives were
reported for any of the normal hybridomas for these allotype
categories. It is not disputed that the normal hybridomas were
not tested for allotype. ORI argued that the listing of
negative results for allotype for the normal data in Table 2 was
therefore "clearly false," and was too explicit a representation
to have been honest error or inadvertent omission, so that it
must be found to be intentional falsification. ORI Br. 81.
We do not agree. The table did not report allotype alone but
only the number of hybridomas that produced antibodies that were
both idiotype-positive and positive for one of the æ allotypes.
It is obvious that those hybridomas which were found to be
negative for idiotype could not fit this category even if tested
in an allotyping assay. Moreover, Dr. Imanishi-Kari admitted
that this one category should have been marked as "not
applicable" rather than "0/144." R. Br. 59.
While Dr. Imanishi-Kari did not test the one idiotype-positive
normal spleen hybridoma for æ allotype, it is understandable that
there would be little reason to ascertain the allotype of the
rare idiotype-positive normal antibody, since it was known
already that æ antibodies in the normal mice were only æb. Cell
paper 247-48. Thus, the evidence barely supports a conclusion
that Table 2 was misleading in this respect, much less that it
was intentionally false.
The Panel concludes that ORI did not prove that this late-
discovered error resulted from intentional falsification and
fabrication.
ORI did not prove that the January fusion data were
fabricated.
ORI charged that the data set it called the "January fusion" data
was fabricated. As described above, Dr. Reis and
Dr. Imanishi-Kari stated that Dr. Reis obtained from
Dr. Imanishi-Kari the results from the normal fusion and combined
it with her own later normal results (R-1:76-80, discussed
above). Dr. Reis specifically identified the data on I-1:106-107
as the "experiment that I used to, to sum the results with my
fusion results." Tr. 2547. ORI's allegation that
Dr. Imanishi-Kari submitted the Cell paper with these specific
numbers and only when challenged by Dr. O'Toole felt compelled to
create a set of data with the matching totals for negative normal
results to add to those on R-1:76-80 is implausible. This theory
would require both Dr. Reis's blind acceptance of numbers to add
to her own totals at the time and active conspiracy in
affirmatively recognizing the pages at the hearing.
As noted above, the only connection that these data had with the
Cell paper was that some of the normal data were used in Table 2.
The data ORI found to be fabricated, however, are data reported
as a series of assays on transgenic lymph node and spleen
hybridomas. In other words, ORI's theory is that
Dr. Imanishi-Kari fabricated these data merely to lend some
credence to normal data, which ORI thinks are also fabricated.
ORI's statistical and document examination findings on this data
go almost exclusively to the transgenic data, however. Moreover,
the statistical findings relate to the yellow tapes on I-1:102 to
104, and the document examination findings relate mostly to the
green tapes on those pages.
ORI's statistical analyses of the January fusion data (yellow
tapes) are based on misconceptions of what that data purported to
be. ORI's understanding of the data was inconsistent with
Dr. Imanishi-Kari's explanation of the assays which she had
provided in March 1988, and with internal evidence in her data as
a whole. Ex. H245, at 3; I-1:102-104. In particular, the
statistical analyses depended on viewing these data as comparable
to control sets of data from Drs. Reis and Weaver, but these data
sets were initial tests for particular antibodies, whereas the
yellow tape results are presented as a "rescreen" of supernatants
from wells that previously tested positive on the same coat with
the same probe. The statistical analyses assumed that, in any
"fusion experiment" (irrespective of the type of experiment or
the experimental conditions), positive and negative values should
be randomly dispersed. The evidence shows that this expectation
was not valid. Moreover, much of the testimony was based on the
conception that a cyclical pattern shown in a plot of assigned
values measuring correlation of the counts according to their
positions on the yellow tapes (which is stronger if the tapes are
rearranged) shows an unexpected pattern in the fused cells as
arranged in wells. The plating of the supernatants from selected
cells in wells for testing, however, would not necessarily
correspond to the original plating of the cells or to any
particular position on the tapes. Once the supernatants were
plated on a 96-well plate (as the I-1 notebook and the parties'
arguments indicate they likely were), it would be logical to test
them in an orderly fashion, arranging them in either eight or 12
well groups, working from one side of the plate to the other. In
either of the most likely orders of the supernatant wells
relative to the tape counts, the relationship of the actual
values to values of neighboring wells does not show a pattern
inconsistent with how the data are presented.
The document examination findings relate largely to the finding
that one piece of green tape containing results for one of the
transgenic fusions has ink of a formula different from the ink on
the rest of the tapes for that fusion. While we agree that this
is odd, we find that innocent explanations are possible and that
fabrication would be a farfetched explanation in light of the
insignificance of the data involved and the indicia that the
entire fusion experiment is genuine. We find that the minor
points made about page I-1:107 are of no consequence in
establishing fabrication.
In this section, we first describe the January fusion data and
related experiments, and explain why there are internal indicia
from the notebook that these data are real data rather than
fabricated data and that the test on the yellow tapes is a
rescreen. We then discuss the statistical analyses and why we
conclude that these analyses are not reliable evidence of
fabrication. Finally, we discuss the Secret Service document
examination analyses and why we conclude that they are not
persuasive evidence from which we would infer fabrication.
The January fusion data on the yellow tapes were a rescreen,
and the January fusion data have internal indicia that they
are real, rather than fabricated.
The notations on the notebook pages are consistent with
Dr. Imanishi-Kari's description of the data in 1988, but ORI
ignored that description in some of its analyses. An analysis of
the data itself supports a conclusion that it is more likely that
these are real data than that they were fabricated as ORI
alleged. Further, we find that the RIA data on the yellow tapes
on I-1:102-104 were a "rescreen."
The January fusion data pages questioned by ORI do not appear in
the notebooks as reporting an isolated experiment, but are
clearly part of an extensive series of interrelated experiments.
ORI presented no forensic evidence of fabrication of the rest of
these experiments (and, indeed, used some of the data sets as
"unquestioned" controls for other statistical analyses). Nor did
ORI elicit testimony from any of the witnesses who appeared who
were also working in the laboratory in this period that Dr.
Imanishi-Kari did not in fact do these experiments. The pages
with related experiments include the following:
An extensive series of tests of different mouse sera which
indicate whether mice offspring were transgenic or normal.
I-1:48-58; I-1:75-79.
A retest (dated 1/17) of some of these mice "for fusion."
I-1:100.
A fusion protocol (dated 1/19) showing: (1) four sets of
fusions, each of which involved both spleen and lymph node
cells from mice, specifically, two mice which tested as
clearly transgene positive in the retests, one which tested
normal in those tests, and one mouse (BG/Jack) which is
described as a normal in the protocol, but not clearly
identified as a mouse that was retested; and (2) notations
about the results of the fusions (which we discuss in part
below). I-1:101.
A protocol (dated 2/4-2/7) stating: "Test hybrids with
à 17.2.25 à [kappa/lambda]* when there is too many and then
à [kappa/lambda]* à æ*." I-1:101.
Six pages of data (that ORI calls the January fusion data)
presented as RIAs dated (2/5 to 2/7) of supernatants of some
of the hybridomas identified as coming from the spleen or
lymph node fusions from the mice identified on the fusion
protocol, or of controls. These pages have two double
columns, each with yellow tapes for a test with an à
[kappa/lambda]* probe on a "G.P. à 17.2.25" coat and green
tapes for a test with an à æ* probe, on a "G.P. à 17.2.25"
coat. I-1:102-107.
Two pages with an ELISA (dated 2/7/85) for isotype of (1)
hybrids from the January fusion, (2) control proteins, and
(3) hybrids from a different fusion. I-1:108-109.
These experiments are interrelated in numerous ways. For
example, the fused cells were from mice identified as transgenic
or normal in the sera retest and/or initial sera test. The four
sets of fusions which the protocol indicates resulted in
uncontaminated growth are assigned the following designations in
the protocol: I-1 (lymph nodes from the first transgenic mouse),
I-2 (spleens from the second transgenic mouse), II-1 (spleens
from the first normal mouse), and II-2 (lymph nodes from the
second normal mouse). The first three of these designations are
noted in red on the sera retest. All of the designations appear
on both the RIAs and the first two appear on the ELISA. The
total number of growth wells for particular sets of hybridomas
(noted in the fusion protocol) either show up as notations on the
RIAs or are the total number of wells tested in the corresponding
assay. The fusion protocol states that the fused cells were
plated in "24 wells (PE)," and the controls for one of the
radioimmunoassays includes "No growth wells" with "PE" in a
circle beside it. The numbers for the hybridomas tested on the
ELISA correspond to numbers for transgenic hybridomas with very
high results for antibody production on the radioimmunoassay.
In addition, there are various markings for particular results of
the assays, such as stars, asterisks, checks and question marks.
Some of the pages are very neat and other have numbers crossed
out or written over. One notation indicates that well number 199
was not done in order on one assay, but the number is assigned to
the last value on a tape.
We also note that the ELISA on I-1:108-109 has some isotyping
results on the January fusion hybridomas that are ambiguous in
similar ways to the ELISA on Table 3 hybridomas that we discuss
below. Dr. Imanishi-Kari explained that she did not use the
experiments related to the January fusion because there was
contamination with fungi. Tr. 5249-51 (Imanishi-Kari); Exs.
H245, at 3, H103, at 109-10. The fusion protocol on I-1:101
indicates that spleen hybrids from one fusion and lymph node
hybrids from another were contaminated.
Overall, the Panel finds that the interrelatedness of the
questioned January fusion data with other pages, the complicated
nature of the fusion, and the various markings on the pages are
indicia that the data are real. These indicia do not fit with
ORI's scenario that Dr. Imanishi-Kari faked the RIAs on the
transgenic hybridomas at I-1:102-104 (and by implication the
normal results at I-1:106-107) because she needed 36 normal mouse
results in addition to Dr. Reis's normal data. We find it
implausible that Dr. Imanishi-Kari exerted a level of shrewdness
and effort beyond that which a fabricator would likely devote to
data of no importance to the paper, other than to lend some
validity to the data for 36 normals reported in the paper. The
ambiguity of the normal data itself undercuts the idea that the
data were faked using such a degree of shrewdness and effort.
Moreover, ORI's scenario would require us to believe that
Dr. Imanishi-Kari had the foresight to fabricate notations
relevant to questions about why she did not ever report the
results from the transgenic fusions and about whether the lymph
node hybridomas tested on I-1:102-104 were prescreened for
idiotype-positive antibodies. As we discuss next, the
prescreening issue arose at the hearing.
The question of whether the RIA results on the yellow tapes on I-
1:102-104 were an initial screen of the hybridoma wells for
particular antibodies (as ORI's statistical analysis assumed) was
raised at the hearing by Dr. Speed. Dr. Speed stated his
understanding that this test was a rescreen only of wells that
had previously tested positive on a screen with the same probe,
and that the removal of no-growth wells preceded this screen.
Tr. 2175-80. ORI disputed this (although part of ORI's analysis
assumed some type of prescreen). Internal evidence in the
notebooks is consistent with Dr. Imanishi-Kari's description that
the fusion wells were screened for growth, and that the
supernatants from the wells with growth were screened on an anti-
idiotype coat with a kappa/lambda probe, before the similar
screen on I-1:102-104. Our reasons are:
The fusion protocol indicates that each set of spleen or
lymph nodes from the fusion was plated on "12 plates 24
wells (PE)" which would be a total of 288 wells for each
set. I-1:101.
The protocol for the RIA indicates that the hybrids should
be tested with a kappa\lambda probe on an anti-idiotype coat
"when there is too many and then" with a kappa\lambda probe
and a æ probe. I-1:101.
The fusion protocol has the following notation for the set
of hybridomas tested on I-1:102-104: "260 wells growth."
I-1:101.
A notation in the lefthand margin on I-1:102 indicates "260
hybrid" and "138 [kappa/lambda] +." This notation and the
numbering of the January fusion data are consistent with
prescreenings for growth and for idiotype-positive
antibodies (using a kappa/lambda probe), followed by testing
on an anti-idiotype coat with a kappa/lambda probe and with
a æ probe.
The pages at I-1:102-104 contain: (1) a total of 138 counts
(rather than the 260 for which growth was indicated), all
with high values on the yellow tapes in the kappa/lambda
column, except a few counts; (2) script numbers between 1
and 260 assigned to the counts (which ORI agreed were well
numbers), with some numbers skipped; (3) five "negative
hybrids" used as controls on I-1:104 which have well numbers
that are skipped in the 138 counts; and (4) "no growth
wells" used as controls on I-1:104, with the notation "PE"
(which refers to the original fusion growth plates) and with
no assigned well numbers.
Thus, we conclude that the internal evidence in the notebook as a
whole indicates that the January fusion data are real, and that
the RIA with the kappa/lambda probe was a rescreen of only
hybridomas which had previously tested positive on the same coat
with the same probe, as Dr. Speed said. We next turn to ORI's
statistical analyses of the January fusion data.
ORI's statistical analyses are not reliable evidence that
the January fusion data were fabricated.
ORI performed two statistical analyses of the data on the yellow
tapes on I-1:102-104. ORI examined the correlation of the counts
on the tapes, and also evaluated the likelihood of a run of 15
positive wells at the end of an experiment.
In the first analysis, Dr. Mosimann applied a technique called
serial correlation analysis. Serial correlation analysis
attempts to quantify the relationship of numbers in a series.
Tr. 695 (Mosimann), 2162 (Speed). Dr. Mosimann plotted the
counts from the yellow tapes and from two sets of "control" data,
as well as the serial correlation "coefficients" he determined
from his analysis of each of these three data sets. Plots of
the serial correlation coefficients for the data on the yellow
tapes from I-1:102-104 show patterns in the sequential
relationships of the counts on the tapes that are generally
cyclical; the cycle was stronger when I-1:102 and I-1:104 were
analyzed together than when the counts from I-1:103 were
included. Ex. H401. The control data sets were from W-2:33-38
(Weaver data) and R-1:27-29 (Reis data). No cyclical patterns
were found in the serial correlation coefficients for the Weaver
and Reis data. Dr. Mosimann said that one would expect in a
"fusion experiment where cells are just sort of combining
randomly" that there will be "no relationship of numbers in the
series with numbers following." Tr. 703-709. ORI concluded that
the yellow tapes were not from a fusion experiment and that the
yellow tape from I-1:103 had been inserted between the tapes on
I-1:102 and 104.
Second, Dr. Mosimann conducted a permutation analysis which
showed that the probability of seeing a run of 15 consecutive
positive wells at one particular place (the end) was small. ORI
Report 121; Tr. 724 (Mosimann). Dr. Mosimann's premise of a run
of 15 positives at the end is based on the well numbers (246-260)
assigned to counts at the end of the yellow tape. The actual
counts on the tape show that one of the wells (number 250) is
clearly negative for idiotype positivity, so the run of positive
values at the end of the tape is only 10. Dr. Mosimann thought
the well numbers from 1 to 260 indicated wells from the original
24-well fusion plates, and that the skipped numbers were supposed
to be numbers of wells negative for growth. Tr. 708, 713-715
(Mosimann). He expressed his opinion that, in "constructing" the
data, Dr. Imanishi-Kari needed to get 138 positives on the assay
out of the 260 wells, and at the end of the construction suddenly
found out she was running out of numbers, and that explains why
the last 15 well numbers are consecutive. Tr. 722.
The Panel finds that neither of these analyses is reliable. The
basic flaw in both analyses is that ORI found that Dr. Imanishi-
Kari had misrepresented data, based on a misconception about how
she had represented the data. The yellow tape counts are
represented as being from a "fusion experiment" only in the sense
that the supernatants analyzed in the assay are from cells
resulting from a fusion. Counts are represented as being from an
assay where most or all of the counts would be positives, because
the supernatants had been prescreened on the same coat with the
same probe. No representation is made about any particular order
in which the cells from the fusion were plated, the well numbers
were assigned, the supernatants were plated, or the wells for the
assay were put into tubes for counting. Dr. Speed recognized the
importance of the assay being a rescreen and expressed his
opinion that the analyses did not show that the data were
fabricated. Tr. 2179-81. The testimony of ORI's witnesses is
not directly relevant to the specific assay at issue here.
ORI argued, however, that we should nonetheless conclude that the
yellow tapes are from a different experiment because: (1) Dr.
Mosimann has more expertise than Dr. Speed in analyzing "fusion
experiments"; (2) testimony from ORI's scientific experts and
analysis of the "controls" established that gamma counter
readings of individual wells in "fusion assays" should be
independent of readings for other wells, no matter what reagent
is used; (3) the serial correlation analysis shows a cyclical
pattern inconsistent with a fusion assay, even if one would not
expect random dispersion; (4) this pattern is also evident in the
counts themselves; and (5) the run of 15 well numbers shows
fabrication.
ORI's arguments lack merit, for the following reasons:
Dr. Mosimann testified that his expectation of randomness
was based on his experience with "fusion experiments." Tr.
703, 705-09. However, when asked whether he would expect
the result in each well of a fusion experiment to be random
with respect to the neighboring well, he admitted that he
was "not necessarily qualified to speak in detail on this."
Tr. 708. Moreover, his articles on "fusion experiments"
relate to cell growth in wells and indicate that an
expectation of randomness depends on experimental
conditions. Exs. H794-A, B. The analysis in the articles
is premised on certain assumptions, including the following:
"After the fusion, the cells must be dispersed (this should
be verified by microscopical observation) and randomly
distributed in the original cell suspension by thorough
mixing." Ex. H794-B, at 37. This statement contradicts
(rather than supports) the notion that randomness should be
expected, regardless of experimental conditions. Dr.
Mosimann admitted that he did not know whether the cells in
the January fusion were thoroughly mixed. Tr. 5829.
Dr. Imanishi-Kari presented unrebutted testimony that such
thorough mixing was difficult in her experiments, given the
delicate nature of the hybrids. Dr. Marrack, who indicated
that she has probably done 30 or 40 fusion experiments,
provided a detailed description of the physical process of
conducting a fusion. She explained how and why clumps could
occur and stated that things never look random on individual
plates because of the way things distribute themselves.
ORI attacked Dr. Marrack's testimony on the grounds that she
never saw the January fusion data or analyzed the plates on
which the assays were conducted. None of ORI's witnesses
analyzed the plates either, however. Dr. Marrack's
testimony that clumping of cells in the flask can lead to
non-random behavior on the plates undermines ORI's general
assumption, whether she saw the January fusion data or not.
In contrast to Dr. Marrack's detailed description of the
fusion process, the testimony ORI presented was very
general. ORI's witnesses did not address the mechanics of
the process or the physical realities described by Dr.
Marrack or contradict her description.
The testimony ORI presented from its scientific experts on
randomness in "fusion assays" (as opposed to plating of
fused cells) was conclusory and appeared to be based merely
on general impressions. Tr. 392 (Dahlberg), 1415-16
(Davie), 1506 (Gilbert), 1618-19 (McClure). Dr. Dahlberg
noted that in Weaver's assay "there are relatively few
positive values . . ." and testified that, based on his
experience with fusion assays, he would expect results with
negatives interspersed like the Weaver data. Tr. 390-91.
Similarly, Dr. Davie contrasted the January fusion with
"other fusions that have been looked at" which are
characterized by stretches of negatives followed by very
high values, because there is no relationship. Tr. 1369.
Thus, their expectations were related to fusion assays that,
like the Weaver data, were an initial screen for a
particular antibody characteristic, not a rescreen assay of
wells already scored as positive in a prior identical
screen.
Dr. Speed testified that he had observed non-random-
appearing behavior in assays on microliter plates. Tr.
5955, 5966-67. His opinion that he would not expect
randomness in fusion assays was also based on analyzing the
Reis data, which showed that the three highest values were
each 12 positions apart. Tr. 2166. Dr. Mosimann
suggested that these were "outlier" values that a
statistician might disregard. Tr. 5624-26, 5831. Even if
these high values may be characterized as outliers and
disregarded (which is questionable), it is significant that
the highest values appear in positions that have some
relation to the plating of the cells in 24-well plates and
the testing the supernatants in 96-well plates. Contrary
to what ORI suggested, Dr. Speed did not claim that the Reis
data had the same serial correlation pattern as the yellow
tape counts from the January fusion, but only that his
analysis of the Reis data displayed a statistically
significant serial correlation that is not consistent with
random data. Tr. 2166-75 (Speed); Ex. R57. ORI did not
effectively rebut that point.
Even if ORI had shown that the "control" data sets were from
assays like the one in question (which ORI did not show),
any differences between the data sets could mean nothing
more than that the fusions leading to the Reis and Weaver
data were done under the experimental conditions assumed in
Dr. Mosimann's articles, and the January fusion was not.
Contrary to what ORI suggested, Dr. Mosimann's serial
correlation analysis does not necessarily show an unexpected
relationship between the wells in a fusion experiment or
assay. The analysis merely shows a cyclical pattern in the
serial correlation coefficients of counts on tape, based on
their sequential position on the tape. ORI presented no
serial correlation analysis showing the relationships
between the values based on the various possible placements
of the corresponding wells on a plate. Dr. Mosimann's
results are inconsistent with an assumption of no
relationship between wells in a fusion experiment only if
the sequential position on the tape necessarily corresponds
to a meaningful position on a well-plate.
Contrary to what ORI argued, the January fusion data on the
yellow tapes do not "demonstrate a strong cyclical pattern
in which the cell counts in sequential wells steadily rise
to a peak, then steadily fall to a valley . . . in a cycle
of 12 radioactivity values." ORI FFCL X.L.iii.11. Our own
visual observation and examination of the data show that,
while there is some general trend of rising and falling,
there are a significant number of interruptions in this
trend, and the placement of the peaks is not consistently in
the middle values of a cycle of 12.
ORI's theory that Dr. Imanishi-Kari took the yellow tapes from a
different experiment was also undercut by the fact that ORI
provided no satisfactory evidence of another type of experiment
that would have led to the serial correlation pattern observed on
the yellow tapes. Dr. Dahlberg ultimately proposed a theory that
the pattern could have been caused by drying on the edges of
plates in an experiment under experimental conditions with an
expectation that every well would be the same. Tr. 6345-47; Ex.
H690. He contrasted this with what he would expect from a
fusion--a random pattern of growth and a random pattern of high
and low values. As explained above, however, the January fusion
data analyzed were presented as a rescreen, for which one would
expect all high values. We fail to see why the experimental
conditions described by Dr. Dahlberg could not as reasonably have
been present in the fusion assay as represented, as in any other
type of experiment. Thus, we simply do not find ORI's arguments
convincing.
The Panel also finds faulty ORI's reasoning, based on Dr.
Mosimann's permutation analysis, that "the unusual compression of
positive well numbers at the end of the series is consistent with
the need to assign a predetermined number of positive wells
(i.e., 138/260) to the numbers on the tapes." ORI Br. 88. This
argument depends on an assumption that there was a predetermined
total so that Dr. Imanishi-Kari was forced to insert more
positives at the end in order to arrive at the required totals.
But there is no basis to think that, if she had been fabricating
these data, she would have had to match any "predetermined
number." These were results for transgenic hybridomas from the
January fusion (not the normals used in the paper) and were not
published anywhere. There was no external constraint that
compelled her to use a predetermined total rather than simply
count the number of positive counts from the tapes and use that
total. If she fabricated the data on these pages, she also
fabricated the totals and had no need to create a run of 15
positives.
In any event, we find that ORI's permutation analysis is not
reliable evidence that the data were not genuine, because:
That analysis again assumes a random distribution of fusion
products into the growth wells, and fails to consider the
testimony of Dr. Marrack, which indicated that clumping of
cells could have contributed to a run of 15 positives by
increasing the likelihood that the last wells would receive
multiple cells per well. Supernatants from these wells
would thus be more likely to contain idiotype-positive
antibodies.
Dr. Marrack's testimony supports the possibility of non-
random behavior anywhere on the plates. In its brief,
however, ORI assumed that such clumping would be more likely
to cause runs at the end of the plate, and then attempted to
show that this would not have been the case with the January
fusion. ORI asserted that the run of 15 positives was
followed by 28 negatives, because the original fusion was
plated into 24-well plates, for a total of 288 wells. ORI's
position assumes that the wells in the 24-well plates were
numbered 1 to 288, and these numbers stayed with
supernatants from those wells throughout the remainder of
the assays. This was contradicted by Dr. Imanishi-Kari's
testimony that well numbers were assigned only to wells
positive for growth. Tr. 4889. More important, page I-
1:104 shows "No growth wells" used as controls with no well
numbers assigned to the counts for these controls and a
circled "PE." The PE refers to the 24-well plates mentioned
in the fusion protocol on I-1:101.
Dr. Speed found statistically significant runs of positives
and negatives in the Weaver data and a statistically
significant occurrence of 15 positive wells out of the last
18 wells in the Reis data. Tr. 2182, 2974, 3014-18; Ex.
R62; ORI Report 113. ORI discounted these findings, arguing
that (1) the Weaver data had "very few negatives," so a run
of positives would not be surprising, and (2) that the
probability of finding 15 positive in the last 18 wells of
the Reis data was <.001, and thus much more likely to occur
than the run of 15 at the end of the January fusion data,
which had a probability of <.0001. ORI Br. 88, n.66; ORI
Reply Br., App. C, at xvii. ORI's arguments ignore that
these occurrences were still statistically significant at
the commonly accepted .05 threshold, the standard ORI
employed to analyze Dr. Imanishi-Kari's data.
The Panel concludes that the statistical evidence relating to the
January fusion is not reliable evidence that the data are
fabricated.
ORI did not prove that the document examination findings
relating to the January fusion data demonstrated that the
data were intentionally fabricated or falsified.
ORI acknowledged that the "bulk" of its document examination
evidence on the January fusion data "relates to the transgenic
portion" at I-1:102-104, although a few document examination
findings related directly to I-1:107 (which contained a part of
the normal data). In fact, the findings deal only with an
inconsistency in ink formula on the green tapes in one of the
transgenic fusions, that for the lymph nodes. We therefore
address first the findings that ORI considered most significant,
i.e., that one portion of green tape on I-1:103 was not
consistent with the green tapes on the I-1:102, 104, 106, 107 and
the rest of 103. We then address the more minor findings on I-
1:107 (i.e., that an ESDA of page I-1:31 contained impressions
from I-1:107 and that the two tapes on I-1:107 differed in the
intensity of ink).
The finding of a different ink formula on one of the green
counter tapes on I-1:103 is puzzling but does not prove
fabrication.
As explained in part earlier, the results of the assays on the
transgenic lymph node fusion are presented in two double columns
across three pages. The left side of each double column contains
yellow tape with results on the anti-kappa/lambda assay. The
right side of each double column contains green tape with results
on the anti-æ assay. The yellow and green tape results are lined
up to show results on the same 138 samples side-by-side. The
Secret Service examiners tested ink samples from multiple
locations on pieces of green tape from the left and right side
double columns on each page. Their central finding was that two
formulas of ribbon ink occurred on the green tapes for the
transgenic lymph node anti-æ assay. One formula was found only
on the green tape on the left side double column of I-1:103. The
green tapes on the remainder of I-1:102-104 all used a second
formula of ink, which also matched that on the normal fusion at
I-1:106-107.
The green tape with the different formula on I-1:103 is not, as
the Secret Service described it, one piece of tape. Instead, we
find that the last three readings are on a separate piece of
green tape, the bottom edge of which exactly matches the top edge
of the green tape in the right side double column on that page.
The Secret Service findings that the green tape in the left and
right side double columns on I-1:103 have different ink would
thus imply that the ink changed in the middle of a single
continuous strip of counter tape without a break in ink intensity
to show a new ribbon. This raises the possibility which was
not addressed at the hearing of inconsistency in ink formula
within a ribbon.
The implication drawn by ORI from the different ink formula used
on a page in the middle of the presentation of data is that such
a difference could not innocently occur as it might if the ribbon
or printer were changed at the end of an assay. But the order in
which the samples are presented here need not reflect the precise
order in which the samples were tested in the gamma counter.
Testing may have been interrupted; one plate may have been run as
a whole and the other tested later; or a portion may have been
saved after an interruption and completed at the end of the
assay. See R. Br. 36, n.43. There is no particular reason to
assume that the normal assay occurred after the transgenic or the
transgenic spleen after the transgenic lymph nodes simply because
of the current order of the tapes or pages.
The Secret Service found other instances of green tapes that
matched each of the two ink formulas found at I-1:102-107. For
the reasons discussed in the overview of document examination
methods, we do not find that these matches provide useful
information about the likely dating of these experiments. They
simply demonstrate that both ink formulas were present in ribbons
used at the laboratory over a wide time frame. As discussed
above, ORI posited changes in ribbon or substitution of printers
to explain similar anomalies in unquestioned data, so innocent
explanations of the puzzling findings on ink formula are
possible.
We find such innocent explanations more plausible in light of the
nature of the data being challenged (again one of two transgenic
fusions submitted only because they were associated with a normal
fusion which was the source only of some of the negative results
in Table 2). In focussing so narrowly on the details of ink
formula, ORI also loses the bigger context of the substantial
evidence from surrounding data (some of which is detailed above)
that this entire experiment was genuine.
The document examination findings concerning I-1:107 do not
prove fabrication.
Mr. Hargett testified that I-1:107 (dated February 7, presumably
1985) was produced prior to I-1:31 (which was dated October 30,
presumably 1984) because they were in registration. Tr. 3311.
However, he acknowledged later that only a few notations from I-
1:107 actually appeared on the ESDA of I-1:31 and that, as to
this page, it was "a possibility" that the registration was
"produced as a result of placing the paired pages in registration
by compiling the individual loose pages." Tr. 3464-66.
ORI also pointed out that the intensity of the ink across the
green tapes on I-1:106 and 107 (the normal spleen and lymph node
fusions) differs; the numbers on 106 and in the first column on
107 are fairly light in ink intensity, and those in the three
right columns on 107 are somewhat darker. See ORI FFCLs
X.L.vi.3-5. All of the values for the samples tested were
negative, but Dr. Dalhberg argued that the negative values on the
green tape with the lighter ink intensity averaged higher than
the negative values on the tapes with the darker ink intensity.
Tr. 6329-32; Dahlberg Decl., Att. 7. The difference in ink
intensity is noticeable, but not dramatic, and again, we cannot
be certain of what the order was in which these samples were
tested, whether the testing was performed consecutively or
interrupted, or whether some toggling or manipulation of the
ribbon occurred to try to get a little more use from it. As for
the difference in background reading levels for negative samples,
Dr. Imanishi-Kari testified credibly that they can vary as an
effect of whether samples were tested using new or previously-
used tubes or of whether the immediately preceding experiment had
very high radioactive readings. Tr. 6457-58. Thus, their
difference in background values could support a conclusion that
part of the experiment was counted at a different time.
In light of the evidence as a whole, the Panel concludes that the
document examination evidence relating to the January fusion is
inadequate to support a conclusion that the data were more likely
than not to have been fabricated.
The Panel concludes that ORI did not prove charges four and five,
Table 2, by a preponderance of the evidence.
C. Table 3
1. Idiotype-positivity of Table 3 hybridomas
Table 3, charges one and two: ORI charged that including a
hybridoma in Table 3 implied that it produced idiotype-positive
antibodies but that Dr. Imanishi-Kari had "experimental evidence"
that eight of the 34 hybridomas listed in Table 3 were not
idiotype-positive. Charge letter 5-6. Therefore, ORI charged
that their inclusion in Table 3 constituted falsification by
deliberately failing to report that fact. Id. In addition, ORI
charged that, for three of the eight allegedly idiotype-negative
hybridomas, the Cell paper contained false affirmative statements
that they were idiotype positive. Id. at 6.
Issues: Table 3 listed 34 specific hybridomas and then provided
information on the serological results (in a column labelled "Ig"
for immunoglobulin) and molecular analyses (in four columns)
for each hybridoma. Cell paper 252. Dr. Imanishi-Kari provided
the information on isotype in the Ig column. Tr. 4693. For some
of the hybridomas, both heavy and light chains are identified,
while for others only a heavy chain isotype is listed. In
addition, four hybridomas are not identified as to isotype at
all; the notation "n.d." is listed in the Ig column for these
four hybridomas.
No explicit assertion appears in the Cell paper that all the
hybridomas listed in Table 3 produce idiotype-positive
antibodies, nor does Table 3 report any findings as to idiotype.
ORI argued that, in light of the central point of the paper that
a high frequency of endogenous idiotype-positive antibodies were
found in transgenic mice, it would have been pointless to include
molecular and serological characterizations of idiotype-negative
hybridomas and that readers would therefore have assumed
inclusion in Table 3 implied idiotype-positivity. ORI Br. 93-94.
In addition, the Cell paper contained two statements that
expressly referred to specifically named hybridomas as idiotype
positive. Of the hybridomas mentioned in those statements,
three were among the eight in Table 3 for which ORI alleged that
the experimental record did not support the claim of idiotype-
positivity.
Dr. Imanishi-Kari denied that it was essential to the paper that
every hybridoma in Table 3 be assumed to be idiotype-positive,
but asserted that she believed all of them were shown by
sufficient experimental evidence to be idiotype-positive, except
those which she listed as "n.d.," or not determined. R. Br. 63-
64.
Analysis: We look first at whether a claim of idiotype-
positivity was in fact made in the paper as to the eight
hybridomas at issue. We then examine the experimental record to
determine if Dr. Imanishi-Kari could have interpreted the data
scientifically as supporting such a claim, if made.
No claim about the serology of the n.d. hybridomas was
implied in the paper; all but one of the four other
questioned hybridomas were expressly identified as idiotype
positive.
ORI argued strongly that, despite the absence of any express
claim to that effect, the paper implied that all the hybridomas
in Table 3 produced idiotype-positive antibodies. ORI Br. 93;
ORI Reply Br. 33-34. In part, ORI relied simply on the emphasis
in the paper on the significance of finding idiotype-positive
antibodies in hybridomas which did not express the transgene.
See, e.g., ORI Br. 92-93 and ORI Reply Br. 33-34, and cites
therein. While it is undisputed that this finding was central to
the paper, it does not necessarily follow that every hybridoma
discussed in Table 3 must therefore be understood to be
represented as idiotype positive. The fact that in several
locations, as ORI pointed out, the authors specify the idiotype-
positivity of individual hybridomas could be read as implying
that those not specifically mentioned were not necessarily
idiotype positive.
ORI also argued that, "while Table 3 does not expressly state
that the 34 hybridomas are idiotype-positive, neither the table
nor the paper make any sense if they are not read as being
idiotype positive." ORI Br. 93; Tr. 1490-91 (Gilbert).
Dr. Gilbert also testified that the table did not identify which
hybridomas were not idiotype-positive, if some were not, and the
molecular analyses on those which were not would have little
meaning. Tr. 1490-96. However, Dr. Dahlberg testified that the
significance of Table 3 would not be impaired if a few of the
hybridomas were not idiotype-positive, so long these were so
labelled. Tr. 515-16; see also Tr. 1407 (Davie). Dr.
Imanishi-Kari took the position that experimental data supported
idiotype positivity for all the Table 3 clones except those which
were identified as "n.d." in the Ig column.
The Panel finds that the dispute about whether Table 3 implied
idiotype positivity is of very limited importance. Of the eight
hybridomas listed in the first charge, four had the n.d. notation
(L3.6.3, L3.13.6, L3.18.5, S1.3.2). We discuss these hybridomas
in more detail in relation to charge three for Table 3.
Generally, we find that the n.d. notation meant that little or no
serological information was available about these particular
hybridomas. Both Dr. Gilbert and Dr. Dahlberg testified that
the table would not lose its meaning by including some idiotype-
negative hybridomas if they were labelled. We conclude that the
n.d. label, while less than explicit, was adequate to make any
implication that these hybridomas were idiotype-positive
relatively meaningless in relation to these four.
Of the remaining four hybridomas listed in charge one, three are
among those expressly named as idiotype-positive (L4.2.6, L3.3.2,
S1.2.6), as noted in charge two. Consequently, the only
hybridoma for which a claim of idiotype positivity might be
implied but is not expressly made is L4.4.3. Since we find
experimental support for idiotype-positivity for all four
hybridomas, we need not reach a final conclusion about whether
inclusion in Table 3, in and of itself, was intended to imply a
claim of idiotype-positivity. We discuss these hybridomas
next.
The experimental record included data which
Dr. Imanishi-Kari could scientifically interpret as
demonstrating idiotype-positivity in all four hybridomas
remaining at issue (not listed as n.d.).
All four of the relevant hybridomas tested positive in an ELISA
assay which Dr. Imanishi-Kari indicated had been done on an anti-
idiotype coat using isotype probes. I-1:83-88; R. Br. 64. In
addition, each of the hybridomas tested as positive for idiotype
in other experiments. R. Br. 64. ORI nevertheless contended
that experimental evidence did not exist, based largely on two
premises: (1) the four hybridomas tested as idiotype negative in
ascites experiments at I-1:48-58 which ORI treated as
definitive and overriding any conflicting results; and (2)
forensic evidence undercuts the reliability of the ELISA and
other assays supporting idiotype-positivity.
The negative results on one set of ascites assays did not
conclusively establish that these hybridomas were idiotype
negative.
On the first point, ORI stated that the "assumption underlying
these charges is that tests on ascites assays are a much more
definitive indicator of . . . idiotype positivity than are tests
on supernatants." ORI Br. 95. It was not disputed that ascites
fluids can contain a much higher concentration of antibodies and
yield clearer results on assays than supernatants containing
antibodies of cultured hybridomas. ORI Br. 95; Tr. 2743
(Wortis). Our review of the ascites results at I-1:48-58 found
negative or at least borderline results for these four
hybridomas. There are two problems with ORI's use of the
results on I-1:48-58 as conclusive in ruling out idiotype-
positive antibody production in these hybridomas.
First, the ascites fluid for each hybridoma requires individual
preparation and expansion, which may not successfully produce
antibody at all or in sufficient quantity. Tr. 2743 (Wortis),
4760-61 (Imanishi-Kari), 1407 (Davie). ORI acknowledged that
ascites results were more definitive than supernatants only
"assuming a properly working assay." ORI Br. 95. Dr.
Imanishi-Kari asserted that the antibody production in the
ascites experiments on the hybridomas at issue in the assay at I-
1:48-58 may have failed. R. Br. 65. However, in its reply
brief, ORI asserted that the I-1 notebook contains evidence of
only one instance of ascites production (on I-1:36) and that it
must have been successful for these four hybridomas because
ascites tests on those hybridomas were done repeatedly (as shown
on a number of pages including I-1:31, 35, 41, and 43).
However, our review of the I-1 notebook does not support ORI's
assumption that ascites were made only once and that these
ascites produced antibody. Page I-1:36 lists 12 hybridomas for
which ascites were prepared, including the four at issue, and
describes protocols (dated 10/26-10/30) for two experiments to be
performed on the ascites fluids on particular subsets of those
hybridomas. The experiments on I-1:31-35 (dated 10/30-10/31)
appear to correspond to those protocols. Later pages, including
I-1:40 (dated 11/23/84) and I-1:44 (dated 11/20-11/21), contain
some evidence of further preparations or at least purification of
ascites from these hybridomas. These preparations may have been
unsuccessful in terms of antibody concentration and may have been
used in the ascites experiments at I-1:48-58. Because the
records are not adequate to track a specific preparation or
purification of ascites used in a particular assay, we have no
basis to conclude that the products of the same ascites
preparation were used for all the ascites assays.
Second, positive results for idiotype were obtained for the same
hybridomas in other assays at I-1:31, I-1:34-35, I-1:41, and I-
1:43. R. Br. 64; Tr. 4759-69 (Imanishi-Kari). ORI disregarded
these results, arguing that some of the results were obtained on
a rabbit anti-124/40 coat rather than the guinea pig anti-17.2.25
and that some of the readings which Dr. Imanishi-Kari interpreted
as positive should be considered negative or ambiguous. ORI
Br. 96-97. We find that these assays, assuming the data are
authentic, provide experimental evidence adequate to support the
conclusion that it was more likely that Dr. Imanishi-Kari made a
judgment at the time that all four hybridomas produced idiotype-
positive antibodies than that she intentionally misrepresented
these hybridomas as idiotype positive. We therefore turn next to
the question of the authenticity of the data.
ORI did not prove by a preponderance of the evidence that
the assays supporting idiotype-positivity for these
hybridomas should be disregarded for forensic reasons.
Finally, ORI argued that the assays which conflicted with its
claim of idiotype negativity for these hybridomas should be
disregarded for forensic reasons. ORI Br. 96. First, ORI has
charged that the ELISA was actually done on an anti-
immunoglobulin coat which would provide no information about
idiotype-positivity. We discuss this charge in detail in
relation to charge six for Table 3 and concluded that it is
without merit. In regard to these charges, ORI argued that even
if the ELISA was a genuine assay for idiotype, its results would
be less reliable than ascites results. ORI Br. 95, n.70. We
turn next, therefore, to ORI's charge that ascites results at I-
1:41 and 43 were fabricated in 1986 and that ascites results at
I-1:31, 34 and 35 are "problematic." ORI Br. 96.
The main document examination attack on I-1:41 and 43 is based on
their supposed relation, along with I-1:30 and I-1:113, to
certain pages in the I-3 notebook, dated in 1986. This
association was based on the pages having been written on pad
paper with the same defect and containing pen inks in some
entries that match in formula. In addition, I-1:41 was linked by
ESDA to I-1:113 (and an ESDA linked I-1:30 to I-3:25, which
reinforced the claim of a relation between this group of pages in
I-1 and some pages in I-3). We addressed above the flaws in
ORI's effort to use these commonalities as a basis to infer that
the I-1 pages were fabricated.
ORI's claim that I-1:31 was "grossly out of order" was based on
Secret Service findings that impressions of I-1:107 (dated
February 7, 1985) appear on an ESDA of I-1:31 in registration,
while impressions of I-1:31 appear on an ESDA of I-1:98. ORI Br.
96; Ex. H500, at 2. ORI concluded that I-1:31 was prepared after
I-1:107. The material in registration is only a heading entry
and little else from I-1:107 appears on I-1:31. The fact that so
little of the writing was impressed on I-1:31 suggests that
registration was not indicative of necessarily having been
written in order on a single pad. Tr. 4212-15 (Richards). The
few entries from I-1:31 that appear in impressions on I-1:98 are
not in registration. As discussed elsewhere, conclusions about
the order in which these pages were written cannot reasonably be
drawn from the sketchy ESDA impressions, in light of the
limitations of the ESDAs in determining whether a page receiving
impressions already contained writing so that impressions were
made merely by laying a page on top of another while adding
entries.
In any case, the Secret Service offered no evidence that the raw
data (i.e., the counter tapes) on I-1:31, 41 and 43 were not
genuine or could not have been generated in October 1984. In
light of our discussion about Dr. Imanishi-Kari's practices in
organizing data, there is no reason why the pages might not have
been put together in 1985 or even later without affecting the
authenticity of the data on them. Furthermore, the protocol on
I-1:36 (an unchallenged page on which ORI relied in discussing
ascites preparation) ties in closely to the experiment on I-1:31
and suggests that the October 1984 date is probably correct even
if the page was compiled retrospectively.
We conclude that ORI did not prove by a preponderance of the
evidence that the data supporting the idiotype-positivity of the
four hybridomas named in the charge letter were fabricated.
The Panel concludes that ORI did not prove charges one and two,
Table 3, by a preponderance of the evidence.
2. Claims about "n.d" notations
Table 3, charge three: ORI charged that Dr. Imanishi-Kari's
"deliberate making of false statements" by noting "n.d." (meaning
"not determined") in the column on isotype for four hybridomas in
Table 3 when data showed them to be negative for any antibody
production was scientific misconduct. Charge letter 6.
Issue: ORI argued that including these four hybridomas in Table
3 implied that they had been determined to be producing antibody
(and, in fact, as discussed above, to be producing idiotype-
positive antibody). ORI Br. at 98. ORI interpreted the notation
"n.d." to mean that the antibody from these hybridomas had not
been tested for isotype.
ORI treated the including the n.d. hybridomas as making two
positive assertions: that these clones produce antibody and that
the antibody is idiotype positive. We find that n.d. may just as
reasonably be read as a negative assertion: nothing is
determined about the serology of these hybridomas. This reading
was supported by Dr. Wortis who testified that the n.d. notation
implied that these hybridomas were simply irrelevant because "we
don't know what is actually being produced by those clones." Tr.
2766.
However, even if we read the n.d. notations as asserting that
antibodies were present and that what could not be determined was
only the isotype of those antibodies, we do not find clear
evidence that the assertion is false, much less intentionally and
deliberately falsified. ORI's claim that the hybridomas were
proven not to produce antibody was entirely based on an ELISA
assay at I-1:83-88. The summary of the results states that the
ELISA was performed on an anti-idiotype coat using probes to test
for various heavy and light chain isotypes. I-1:83.
Consequently, the ELISA would provide information on the isotypes
of all antibodies captured by the anti-idiotype coat and would
provide no information about the isotype of idiotype-negative
antibodies. The four hybridomas listed in Table 3 as n.d. for
isotype were tested in the ELISA as negative for all isotype
probes. Based on this assay, therefore, it would not be
possible to determine if the hybridomas were producing no
antibody or the antibody which they produced was not captured by
the idiotype coat.
ORI believed that this assay demonstrated that the hybridomas
produced no antibody because ORI accepted the assertion by
Dr. O'Toole that this ELISA was actually performed using an anti-
immunoglobulin reagent which would capture all antibodies. If
that were the case, negative results on all the heavy and light
chain probes would seem to rule out the presence of antibody
(assuming no problems in the preparation of the samples or the
functioning of the reagents). However, for reasons discussed in
detail in a later section, we find that the ELISA was performed
as recorded on an anti-idiotype coat. We therefore conclude that
this assay did not show that the four hybridomas were not
producing antibody.
Dr. Dahlberg agreed at the hearing that the charge that the use
of n.d. was incorrect was "based totally" on the assumption that
an ELISA using an anti-immunoglobulin coat had found no antibody
production. Tr. 519-20. In its brief, ORI also intimated that
the charge should be sustained because including the four n.d.
hybridomas "suggested a level of idiotype positivity that was not
present." ORI Br. 98; see also ORI FFCL XI.C.ii.12.
Dr. Imanishi-Kari testified that these four were not idiotype-
positive, based on the ELISA results. Tr. 4754, 4779. We
discuss elsewhere the dispute about whether Table 3 generally
implies idiotype positivity for those hybridomas not specifically
referenced in the text as idiotype positive. If the reader
understood these four additional hybridomas to be idiotype-
positive antibody producers, the reader might draw an implication
from the molecular results in Table 3 that the heavy chains were
endogenous since the molecular results indicated that the
transgene was not being expressed. ORI did not prove, however,
that the central point of the paper would have been undercut if
no information at all were provided on these hybridomas.
Overall, we do not find it plausible that Dr. Imanishi-Kari was
more hybridomas that produced idiotype-positive antibody while
listing them as n.d. and therefore offering the reader no
information about their serology. ORI understated the
pointlessness of such a misrepresentation in acknowledging that
it would make the hybridomas "less interesting." ORI Br. 98. If
Dr. Imanishi-Kari deliberately intended to mislead readers, it is
more likely that she would have put an endogenous Ig for these
hybridomas and explicitly stated that they were idiotype
positive.
The Panel therefore concludes that ORI did not prove charge
three, Table 3, by a preponderance of the evidence.
3. Double producers
Table 3, charges four and five: ORI charged that
Dr. Imanishi-Kari failed to report in the Ig column of Table 3
that nine hybridomas reported as expressing only an endogenous
heavy chain also expressed a æ heavy chain, and this was
deliberately misleading and a falsification. ORI also charged
that the statement in the Cell paper that "[a]ll of our
hybridomas did secrete Ig, yet none produce two Ig heavy chains"
was a deliberate false statement since there was experimental
evidence that 13 hybridomas were double producers. ORI asserted
that these acts constituted scientific misconduct. Charge letter
6-7.
Issue: ORI claimed that Dr. Imanishi-Kari had experimental
evidence that 13 of the Table 3 hybridomas were double producers,
because two heavy chains (æ and either þ or à) were scored
positive in the ELISA at I-1:83-88 for these 13 hybridomas and
some of the hybridomas (reported in Table 3 as endogenous) also
scored positive for transgene æ in the assay at R-1:19-24 or
other assays. Dr. Imanishi-Kari said that she did not draft the
double producer language in the text, but agreed with it, so long
as the proper definition of double producer is used. She said
she had ruled out the existence of double producers by subcloning
or relying on the molecular data. Dr. Imanishi-Kari said that
she did not rely on the assay at R-1:19-24 because BET-1 was not
working specifically in that assay and because there was a strong
possibility of contamination. ORI argued that she was
responsible; that some of her subcloning data were fabricated;
that, in any event, the subcloning data are ambiguous or
nonexistent for five of the clones; and that she could not rely
on the molecular data. ORI argued that Dr. Imanishi-Kari should
have reported in Table 3 that both heavy chains scored positive
in the ELISA.
Analysis: For reasons we explain in part elsewhere, we conclude
that ORI did not prove that any subcloning data were fabricated.
As we explain in this section, the record as a whole supports a
conclusion that Table 3 and the statement about double producers
reflect an honest difference in interpretation or judgment of
data, rather than that they are deliberately false, for the
following reasons:
ORI's findings ignore the textual and experimental context
in which the statement about double producers was written
(possibly in editing of the paper and likely not by
Dr. Imanishi-Kari). The text relates to whether more than
one heavy chain was "stably transcribed," and does not imply
that no other heavy chains were ever detected. Draft
language supports testimony of Dr. Imanishi-Kari's witnesses
that, at the time, she would have approached the question
from the viewpoint that she would need proof of stable
double producers before reporting more than one heavy chain
for a hybridoma.
ORI's proposed definition of "double producer" would include
a well containing more than one cell line. This definition
was not supported, even by ORI's own experts. Dr.
Imanishi-Kari's definition was supported by key witnesses,
as was her view that subcloning would be the primary way of
determining whether there was a true double producer or
merely more than one cell line per well.
Internal evidence in the data supports the view that
Dr. Imanishi-Kari did not disregard evidence of possible
double producers but that she and Dr. Reis did considerable
work to more fully characterize hybridomas tested by the
ELISA. Dr. Reis corroborated Dr. Imanishi-Kari's testimony
about why they did not interpret the assay at R-1:19-24 as
ORI did. When Dr. O'Toole first asked questions in 1986
about double producers, she was told by Mr. Albanese that
subcloning was done.
ORI did not establish that Dr. Imanishi-Kari had a motive to
deliberately misrepresent whether she found double
producers. There is conflicting testimony on whether such a
finding would undercut the central thesis of the paper
(depending on whether the endogenous heavy chains were
associated with idiotype-positivity). Even if the thesis
would have been undercut, however, data proving the
existence of double producers would have been worth
reporting.
The data as a whole are consistent with Dr. Imanishi-Kari's
assertion that she made a judgment based on the serological
and molecular data that she did not have proof of double
producers. ORI raised questions about interpretation of
some of the subcloning and other data and about the
soundness of relying on the molecular data for some of the
hybridomas. Some of ORI's interpretations have no merit,
while others raise serious scientific questions. The issue
here is not whether the judgments were sound, but whether
this is indeed a case where honest judgments were made,
rather than a case of deliberate falsification. In
evaluating the latter issue, ORI ignored the fact that some
of the hybridomas which ORI questioned vigorously were
chosen for gene sequencing and analyzed in detail in the
Cell paper which shows that the authors did not simply
disregard seemingly conflicting results.
The dispute about double producers was confused by lack of
clarity in what Dr. O'Toole was alleging, but we agree with
others who have sought to evaluate the dispute that it is at
heart a scientific one.
We discuss the basis for each of these conclusions below.
ORI's findings ignored the textual and experimental context.
The paragraph in the Cell paper that addresses double producers
is in the "Discussion" section and states:
Many transgene hybridomas from either M95 or M54 transgenic
mice retain the transgenic DNA but do not stably transcribe
the transgene (Figure 3 and Table 3). One might have
expected that even if many clones expressing endogenous
genes were selectively expanded, they would be double
producers of heavy chains, as has been observed with TNP-
specific æ + [kappa] transgenic mice (Rusconi and Kohler,
1985). All of our hybridomas did secrete Ig, yet none
produced two Ig heavy chains. Apparently, the transgenic
DNA transcription is repressed by some mechanism that spares
the endogenous rearranged Ig heavy chain genes.
Cell paper 256 (emphasis added). An earlier draft of the paper
(shown to Dr. O'Toole for her comments) reads much differently.
Ex. H227, at 21. This draft contains a description related to
Dr. Weaver's earlier work, in which he found "that the æ
transgene is expressed in all transgenic A-MuLV- transformed pre-
B cells. . . ." Id. This draft also states that it "is probably
significant that we have never observed double-producers." Id.
ORI provided no specific evidence about who drafted either
version; changes may have been attributable to editing to make
the discussion more succinct. We find it significant that the
earlier version is consistent with what Dr. Imanishi-Kari
testified her approach would have been at the time: that she
needed proof of double producers to report more than one heavy
chain for a hybridoma.
Dr. Imanishi-Kari's explanation of the experimental climate was
also supported by Dr. Baltimore, who testified that the statement
about double producers was made in the context of discussing
allelic exclusion (the concept that the expression of one Ig
heavy chain prevents the expression of a second chain). Tr.
2061-63 (Baltimore), 4695-96 (Imanishi-Kari). This concept was
based on previous work by Dr. Baltimore (a Nobel prize winner)
and supports a conclusion that Dr. Imanishi-Kari would have
evaluated her data as showing double producers only if she had
conclusive evidence. Also, the paragraph as a whole indicates
that the kind of double producer being discussed is a very
specific one: one cell producing two antibody heavy chains, one
a æ and another a þ or à.
Finally, ORI's analysis of this question completely ignores the
reference in the paragraph at issue to whether the transgene was
"stably transcribed." Based on their previous work, the
authors would have expected the transgene to be transcribed, and
Dr. Reis worked with subclones looking for stable æ producers.
Cell paper 255; Tr. 2522 (Reis); Dahlberg Decl. 13. Dr.
Gilbert's testimony supports the idea that the focus should be on
"cells with fixed properties as opposed to changing ones." Tr.
1552-53 (Gilbert).
ORI's reliance on certain data as showing double producers
is based on an erroneous definition of double producers and
on a misreading of the data.
ORI proposed that we use the following definition of double
producers in evaluating these charges:
Operationally, a culture or clone of a cell producing two
different heavy chains, May be due either to co-expression
by a single cell clone of two different heavy chains, or to
the presence of more than one clone of cells in the culture.
Glossary 12 (unnumbered). Dr. Imanishi-Kari proposed the
following definition:
A clone (or single cell) producing two different heavy
chains or two different light chains. Double producer and
co-expressor are synonyms. Finding more than one clone in a
culture does not amount to having a double producer. A
culture (well or flask) may be "double positive" due to the
presence of more than one clone of cells. This should not
be confused with true double positives.
Id. ORI's key scientific experts, Drs. Davie and Gilbert,
supported Dr. Imanishi-Kari's definition rather than ORI's. Tr.
1400 (Davie), 1524-25 (Gilbert); see also Tr. 1957 (Eisen), 2058-
59 (Baltimore), 2369-70 (Weaver), 2749 (Wortis), 511-12
(Dahlberg).
ORI determined that 13 hybridomas from Table 3 were double
producers because they "scored positive" on the ELISA at I-1:83-
88 for either þ and à and "scored positive" for æ. Results of
the ELISA are scored in columns on I-1:83-86 for 146 hybridomas,
some of which were tested twice. Column headings include the
following heavy chain reagents: anti-æ, anti-þ1, anti-þ3, anti-
þ2B, anti-þ2A, and anti-à. In each column, readings are recorded,
ranging from +/- to +++. These scores indicate
Dr. Imanishi-Kari's judgment about whether the degree of color
she observed in each well indicated a reaction.
Nine of the 13 hybridomas ORI said were double producers on the
ELISA were reported in Table 3 as expressing endogenous heavy
chains (L3.10.6, L3.4.4, L3.9.4, L4.13.2, L4.5.2, L4.7.2, L4.8.2,
S1.3.1, and L4.10.1), and four were reported as expressing æ
heavy chains (S2.14.4, L3.14.5, L4.14.3, S2.15.6). ORI said it
did not dispute that the ELISA was authentic isotyping data
(although alleging that the coating reagent for the ELISA was
falsified). ORI also said that seven of the nine hybridomas
reported as having endogenous heavy chains scored positive for
BET-1 on the assay at R-1:19-24. ORI also cited other data for a
few hybridomas, which ORI said indicated that they were transgene
æ producers. ORI Br. 101, n.79.
Contrary to what ORI suggested, a positive score on the ELISA for
more than one heavy chain would not by itself be evidence of a
double producer, under the definition agreed to by Drs. Davie and
Gilbert. The possibility would exist that the well (although
assigned a clone number such as L4.7.2) contained more than one
cell line. Moreover, contrary to what ORI's findings implied,
some of the hybridomas were scored +/- for one of the two heavy
chains, not as an unambiguous positive. A few of the hybridomas
at issue were retested in the ELISA, with different results the
second time.
Dr. Imanishi-Kari has testified that she did not consider her
ELISA results to be fully reliable because she had to read the
assay by eye since she did not have an ELISA optical scanner.
Tr. 4679-80. Dr. Dahlberg accepted as true that she did not have
a scanner. Tr. 492-94. To read the ELISA, she had to determine
the degree of color intensity, which involves judgment. The fact
that there are many +/- or + results indicates that her initial
reading was very conservative. A summary column on each of the
ELISA pages (which is next to the last column) indicates one or
more heavy chains for each hybridoma; these notations were
apparently made some time before Dr. Reis did her experiments in
May 1985. R-1:19; Tr. 2518-20 (Reis). While two heavy chains
are recorded in this column for some of the 13 hybridomas at
issue, for others only one heavy chain is recorded. Some of
these are hybridomas with only +/- or + for the second heavy
chain. Thus, her evaluation of the ELISA results some time prior
to May 1985 was not the same as Dr. Dahlberg's.
ORI also is mistaken in relying on the assay at R-1:19-24 as
showing double producers for seven hybridomas which ORI said
showed positive for æ on this assay. ORI Br. 101. First, a æ
result alone would not establish a true double producer, as
discussed above. Second, Dr. Imanishi-Kari testified that she
did not consider the results of this assay reliable because BET-1
was not working well and because there was possible
contamination. Tr. 4827-29. Dr. Reis corroborated this
testimony. Tr. 2514-18. ORI tried to rebut the contamination
explanation through testimony by Dr. Dahlberg that contamination
would have had different effects. This testimony made
assumptions about the type of contamination that are not
warranted. More important, however, the reagent problem alone
provides a reason not to rely on the positive results for
transgene æ.
ORI did not show that the subcloning data are fabricated or
falsified.
The testimony of virtually all of the scientific witnesses
recognized subcloning as the technique that would ordinarily be
used to distinguish between a single clone that was a double
producer and multiple clones in a well. Tr. 511-13 (Dahlberg),
1401 (Davie), 1531, 1553 (Gilbert), 2750, 2757 (Wortis), 1781
(Huber), 2059 (Baltimore). The record supports a conclusion that
Dr. Imanishi-Kari recognized this and did subcloning of all but
three of the 13 clones ORI said were double producers. ORI did
not challenge all of the subcloning data, but challenged the
following pages based on document examination evidence: I-1:97-
99, 119, and 121. ORI also relied on statistical evidence for I-
1:121. We discuss elsewhere the evidence on I-1:119 and I-1:121,
and why we conclude that ORI did not prove that those pages were
fabricated. In this subsection, we discuss testimonial and
documentary evidence that supports a conclusion that subcloning
was in fact done and other reasons why we conclude that ORI did
not prove that pages I-1:97-99 were fabricated.
As noted above, ORI did not claim that the ELISA was not real
isotyping data. On the ELISA, red circles appear around certain
of the hybridoma numbers on the left of the pages, including
eight of the 13 at issue. The following notation appears in red
ink on I-1:86: "Subclone again the circle over." Thus, there is
internal evidence that Dr. Imanishi-Kari recognized the
importance of subcloning for most of these clones to determine
whether the two heavy chains were from one or more cell lines.
Dr. O'Toole claimed that she saw the ELISA at the Wortis meeting,
but she did not claim that the red circles or the notation were
not on the ELISA then. The red circles correspond to hybridomas
listed as being subcloned, frozen, and transferred in 24 wells on
pages I-1:95, 95A, and 96. There is other evidence that
subcloning was in fact done. The notation "subclone" is next to
hybridoma L3.9.4. on I-1:25 and 27. Also, Dr. O'Toole testified
that, when she questioned Mr. Albanese in May 1986, after
discovering the 17 pages, about whether he had detected some æ
related to hybridomas reported as having endogenous heavy chains,
he indicated yes, but that subcloning was done. Tr. 1007-09.
Dr. O'Toole's contemporaneous notes of her conversation with Mr.
Albanese refer to subcloning. Ex. H19 (Dr. O'Toole notebook) at
2A.
The analysis of subclones is shown in the notebooks as done in
part by Dr. Reis and in part by Dr. Imanishi-Kari. Dr. Reis was
trying to find stable æ producers. Tr. 2522 (Reis); Dahlberg
Decl. 13. Dr. Imanishi-Kari's work included using reagents to
detect þs. ORI did not allege that the Reis data were
fabricated, and in fact, relied on it as showing that some
hybridomas were double producers. If the Reis data on subcloning
were the only subcloning data, and Dr. Imanishi-Kari's were
fabricated, this would suggest that Dr. Reis conspired with
Dr. Imanishi-Kari to hide evidence of double producers--a
scenario which we find on the whole to be implausible,
particularly since Dr. Reis left her notebook in an accessible
place in the laboratory when she left for Brazil.
The evidence that the need for subcloning was recognized at the
time, and that Dr. Reis did some of the subcloning, undercuts a
scenario of fabrication of the subcloning data in general.
The evidence on which ORI relied as showing that pages at I-1:97-
98 are fabricated (and which ORI said was unrebutted and
undisputed) is based on the Secret Service analyses.
Specifically, ORI relied on findings that: (1) the original date
on page 97 was 10/12, but it was changed to 1/10/95 (and there
were similar date changes for related pages); (2) the tapes on
these pages are "most consistent" with the tapes being produced
in October 1984; and (3) page 96 (which ORI called a "summary of
results") was "produced prior to" I-1:36, which is dated 10/13.
ORI said that this showed that the data were fabricated because
it showed the original date was 10/12. Based on pages I-1:28-29,
ORI concluded that hybridomas L3.5.2 and L4.13.2 were not
available for subcloning until 10/8 and L3.10.6 was not available
until between 10/8 and 13. ORI then concluded that supernatants
from subclones could not have been available by 10/12, citing
Dr. Imanishi-Kari's testimony that it takes at least 10 days to
grow up a subclone for testing. See ORI Br. 103-04; Tr. 4821
(Imanishi-Kari).
This evidence is unpersuasive, for the following reasons:
The numbers such as L3.5.2 and L3.10.6 derive from cloning
of the parent wells shown as being done starting 8/30/84 and
9/18/84, so there is no reason to believe that subclones of
these clones could not have grown sufficiently to be tested
by 10/12. The mere fact that the records indicate no
freezing of a few of these clones until around 10/12 does
not necessarily imply that they had not grown sufficiently
to subclone 10 days prior to this date.
The date changes on I-1:96-98 are obvious. ORI briefs
suggested no motive Dr. Imanishi-Kari would have to falsify
the dates other than to suggest that she first put 10/12,
then realized that this was not credible because of the
freezing dates so she then changed to a later date. Since
the freezing theory has no merit (and, in event, would not
explain why a fabricator would make an obvious date change
to these pages instead of redoing the freezing lists), ORI
did not establish any reason why it makes a difference when
the tests were done.
While ORI asserted that the Secret Service concluded from
the ESDA of I-1:36 that page I-1:96 was "produced prior to"
I-1:36, this assertion was wholly unsupported. Mr. Hargett,
one of the Secret Service examiners, testified that the
statement in their report to that effect was an error and
the correct finding, which was also in the report, was that
I-1:96 was produced "on top of" I-1:36, which implies
nothing about the order in which they were produced. Tr.
3238; Ex. H500, at 2. This is clearly the correct
conclusion. Page I-1:36 is a spiral notebook page, and
therefore not from the same pad as I-1:96. An independent
review of the ESDA shows that impressions from I-1:96 that
appear on the ESDA of I-1:36 are not in registration with
the page or each other. Thus, there is no basis for
concluding which of these pages was produced before the
other.
ORI also relied on other ESDA analyses, which ORI said
showed that I-1:98 was produced after a page dated 10/30/84.
ORI FFCL XI.B.iii.b.5. If true, this would be consistent
with the January dates now on the pages. We do not,
however, rely on these analyses. ORI misstates what the
ESDA for I-1:98 shows, since the impressions do not appear
in registration. Compare ORI FFCL X.B.iii.b.5 with Tr.
3479-80 (Hargett). We find they are inconclusive as to the
date or dates the data were in fact recorded on I-1:97-99
(which, as noted above, could differ from the date or dates
the tests were actually performed).
The Secret Service finding that the tapes are "most
consistent with" other tapes produced in October 1984 is
similarly inconclusive.
Thus, we conclude that ORI did not prove that subcloning data
were fabricated or falsified.
The data are consistent with a judgment having been made
that there were no double producers.
Dr. Imanishi-Kari has said that she made judgments based on a
combination of the serological and molecular data. Contrary to
what ORI argued, we do not find her statements on this to be
inconsistent, nor do we agree that her statements suggest that
her decisions were necessarily based on a "convergence of both
types of data, each leading to the same conclusion." ORI Br.
106. She has also been consistent in stating that she found some
tests to be more reliable than others.
ORI effectively admitted that, if the subcloning data are not
fabricated, the data would support a conclusion that some of the
13 hybridomas were not double producers. ORI Br. 103. ORI
argued that for some of the hybridomas there is no evidence they
were subcloned, and that, for others, the subcloning results are
ambiguous or incomplete. ORI challenged whether Dr. Imanishi-
Kari could reasonably rely on the molecular data, generally and
with respect to particular hybridomas. For other hybridomas, ORI
argued that the laboratory results were "discrepant." ORI FFCL
XI.B.iii.a.12.
Dr. O'Toole and others posited that a low-level expression of æ
might not give a clear result on a molecular assay and that the
molecular assays were not as sensitive as the serological assays.
ORI said the key issue, however, was the timing of the subcloning
results relative to the molecular results. ORI pointed out that:
(1) it is undisputed that hybridomas tend to lose chromosomes
over time and through subcloning; and (2) Dr. Imanishi-Kari and
Dr. Wortis had said that other phenomena--class switching (also
termed "translocation") and transactivation--can change isotype
expression over time. ORI Br. 102, citing Tr. 4716-17, 4723-24,
4807, 4877 (Imanishi-Kari), 2780-81 (Wortis), 2108 (Baltimore),
2827 (Capra), 1503 (Gilbert), 345 (Dahlberg); Ex. H150 (Journal
article at 3311, 3323).
The testimony shows some difference of opinion over the extent to
which it would be reasonable generally to rely on molecular data
in making judgments about double producers. Dr. Davie noted that
Dr. Weaver was simply assuming all of the hybridomas were "clean,
single heavy chain expressors" and was not doing his studies to
address the double producer issue. Tr. 1379-80. Dr. Gilbert
expressed concern that low level æ transgene expression might be
missed in a molecular assay if a small amount of æ on the
molecular test were ignored. Tr. 1496-97. On the other hand,
Dr. McClure testified that a combination of serology and
molecular analysis could tell "what protein of a particular
idiotype is being produced, and where that protein could be
coming from in terms of its gene expression." Tr. 1639-40. Dr.
Baltimore said that there is no general answer to the question of
whether the molecular assays would be more or less sensitive than
the serological assays, because it depends on a variety of
technical things, such as the nature of the probes and the amount
of radioactivity. Tr. 2060. He described the S1 nuclease test
as a "precise measure of whether the transgene is expressed" and
the 17.2.25 molecular test as a "somewhat less precise measure
[that] should overlap" the S1 nuclease test. Tr. 2055-57. Dr.
Eisen said there was no reason here to think that the molecular
assays were less sensitive than the serological ones. Tr. 1955-
57.
Overall, the record supports a conclusion that, in some
circumstances, it might be reasonable to rely on a combination of
molecular and serological data in evaluating whether double
producers exist. Whether a connection could properly be drawn
between the particular molecular and serological assays here is a
more serious scientific issue, given possibilities such as loss
of chromosomes and class switching. ORI did not establish,
however, that Dr. Imanishi-Kari would have fully understood these
issues and their implications at the time of the Cell paper, and
the record indicates to the contrary. The papers discussing
these phenomena submitted by ORI were not published until the
early 1990's. See, e.g., Ex. H151; Cf. Tr. 420-22 (Dahlberg).
Moreover, Dr. Wortis indicated that it would be possible to trace
cloning and subcloning and to connect it to the molecular data to
make determinations of whether there were double producers. Tr.
2874-77.
In any event, the soundness of making judgments about double
producers based on a combination of serological and molecular
data is not what is at issue here. The issue before us is
whether the Cell paper reflects judgments or interpretations of
data which, if in error, were honest error rather than deliberate
falsification. Based on our examination of the hybridomas for
which ORI said (in one place or another) that the subcloning did
not exist or was ambiguous, we conclude that this is a case where
honest judgments were made based on the data, not a case of
fabrication.
Our examination differed from ORI's for various other reasons,
including the following:
In evaluating the data for these hybridomas, ORI examined
the data from the perspective that Dr. Imanishi-Kari was
obliged to report a hybridoma as a double producer even if
she had only an ambiguous reading for a second heavy chain
or unambiguous readings that could indicate two cell lines
in a well, unless she had definitive evidence to rule out
the second heavy chain. As discussed above, this approach
ignores the textual and experimental context which suggests
that she likely had a different approach.
As discussed below, ORI treated a +/- or a + on the ELISA as
a "positive score" for æ, whereas the record indicates that
Dr. Imanishi-Kari considered the ELISA readings as not
wholly reliable and these scores may have been reevaluated
as negatives for some hybridomas, including for some where
there was consistency in results for all hybridomas from one
parent well.
ORI relied on positive BET-1 results for the assay on R-
1:19-24, whereas the record shows that Drs. Imanishi-Kari
and Reis likely disregarded these results because they
considered them unreliable.
ORI disregarded the subcloning results on pages ORI found
were fabricated but did not prove were fabricated.
ORI relied on results of assays by Dr. Reis that showed some
production of æ after subclones had grown up, but may have
been interpreted as not showing stable transcription of æ in
a single cell line.
ORI disregarded a few molecular results because Dr. Weaver
no longer has the underlying data. Based on the record as a
whole, we concluded that Dr. Imanishi-Kari likely either
relied on Dr. Weaver's representation of his results at the
time, or merely misunderstood them.
ORI failed to take into account all of the information in
the record, including the S1 nuclease results and sequencing
data for some of the hybridomas which appears in the Cell
paper, and interpreted other data in a way which is not the
only reasonable way (such as using a cut-off for ascites
results different from what Dr. Imanishi-Kari likely used).
We do not consider it necessary to discuss each of the hybridomas
at issue in detail, since our conclusions are consistent with
that of the NIH Scientific Panel and since ORI conceded that it
would not have found scientific misconduct if it had not found
that data were fabricated. We make a few general observations
here about subsets of hybridomas that ORI particularly
questioned, and why we conclude that the data are consistent with
Dr. Imanishi-Kari having made judgments, as she said she did,
based on a combination of the serological and molecular work.
For hybridomas which were not subcloned, the æ results on the
ELISA were ambiguous and the isotypes listed in Table 3 were
consistent with molecular results, including negatives on the S1
nuclease. Where the hybridomas were subcloned, the subcloning
could be read as confirming either that a weak result for the
second heavy chain in the ELISA was a false positive or that
there were two cell lines in the well. The molecular data either
as maintained or as previously reported are consistent with a
judgment having been made that there was no stable double
producer, and that the molecular results corresponded to the
hybridoma cells with the serological results for the heavy chain
reported. For all of the hybridomas where ORI alleged that the
laboratory results were discrepant (L4.13.2, L3.4.4, and L3.9.4),
subcloning separated out a stable þ producer, which was
consistent with the molecular results, and sequencing was done
which is reported in the paper. See Cell paper, Figs. 5, 6,
and 7.
ORI particularly questioned the reporting of only a þ heavy chain
for hybridoma L4.13.2 (even though the serological results seemed
to definitively rule out æ production) because there was some æ
detected on a molecular assay. ORI ignored the fact that this
hybridoma was not only sequenced, but was described in detail in
the Cell paper, including the fact that the RNA hybridized to the
VH portion of the æ transgene. Cell paper 252-53, Figs. 4, 5, 7.
Sequences of other hybridomas at issue, including L.4.5.2, were
also reported. Id. This reporting further undercuts ORI's
finding of intentional falsification.
ORI did not establish that Dr. Imanishi-Kari had a motive to
deliberately falsify the identification of the heavy chain
in Table 3 or the statement about double producers.
ORI did not support its position that Dr. Imanishi-Kari had a
motive to deliberately misrepresent the data on whether there
were double producers. ORI's position that the central thesis of
the paper would be undercut by evidence of double producers is
contingent on there being no evidence of idiotype-positive þs,
which was based on viewing the ELISA as being done on an anti-
immunoglobulin coat and other data being fabricated. Drs. Davie
and Eisen testified that the central thesis would not be undercut
by finding double producers if there were also evidence of
idiotype-positive þs. Tr. 1405-06 (Davie), 1957-59 (Eisen). Dr.
Gilbert also seemed to recognize that finding idiotype-positive
endogenous heavy chains on an anti-idiotype coat would be the
"killer experiment" crucial to the paper's central thesis,
although he appeared to suggest that this would not be enough.
Tr. 1492-98. Dr. Gilbert's opinion on this whole issue, however,
was influenced by the fact that he considered the forensic and
statistical evidence to be evidence of fabrication; moreover,
Dr. Gilbert testified that he "reviewed a small amount of
laboratory notebook data in this matter," so his scientific
judgments might have been different if he had reviewed all of the
data. Tr. 1465, 1504-05. Dr. Baltimore testified that finding
double producers would not undermine the central thesis of the
Cell paper that introduction of the transgene altered the
endogenous repertoire of gene expression, and Dr. Dahlberg
agreed, on the condition that "there are id positive þs in high
frequency." Tr. 528-29 (Dahlberg), 2058-59 (Baltimore); see also
Tr. 4806 (Imanishi-Kari).
Moreover, in the experimental context, a finding of double
producers might itself have been worth reporting.
This dispute is, and always was, a question of scientific
interpretation or judgment.
The question of whether the idiotype-positivity observed for the
fused hybridomas was coming from the transgene or endogenous
genes was raised by Dr. O'Toole early on, and is related to the
question of whether Dr. Imanishi-Kari was detecting æ heavy
chains and ignoring them. These questions may not have been
fully analyzed from Dr. O'Toole's perspective because the
scientists who first considered Dr. O'Toole's allegations thought
that she was positing æ/þ heterodimers. It is uncontroverted
that such heterodimers do not exist. Dr. O'Toole has alleged
that these scientists have misrepresented her point, that the æ/þ
heterodimer theory was "concocted to discredit her," and thus
implied that they are involved in a conspiracy against her.
Tr. 1060. In her memorandum to Dr. Eisen, however, Dr. O'Toole
specifically referred to heterodimers, and the memorandum can be
reasonably read to raise the possibility of æ/þ heterodimers.
Ex. H231. Based on hearing all of the testimony presented here,
we reject the notion of a conspiracy and conclude that these
scientists honestly felt Dr. O'Toole was raising only scientific
issues (even if they misunderstood what those issues were), that
a central issue to Dr. O'Toole was æ/þ heterodimers, and that
Dr. Imanishi-Kari had satisfactorily responded.
ORI took the position that it was misleading not to report a
second heavy chain detected at any time. We determine, however,
that Dr. Imanishi-Kari made a valid point that such reporting
could have been misleading. In context, reporting second heavy
chains without further explanation might have suggested that the
authors had evidence of stably transcribed transgene æs and þs
from a single cell clone. A complete explanation of the ELISA
results and why she did not consider them reliable, as well as of
all of the further serological and molecular testing, would have
taken substantial additional space in the Cell paper. While Dr.
Gilbert said he considered it "bad practice" not to report the
second heavy chain, he explained that he viewed such failure to
report as the authors substituting their "subjective judgment"
for that of the readers. Tr. 1553-54. Even if we were to find
that the failure to report the second heavy chain were bad
practice here, that would not be tantamount to a finding of
deliberate falsification.
In sum, we think that this dispute is, and was, a scientific one.
The Panel therefore concludes that ORI did not prove charges four
and five, Table 3 by a preponderance of the evidence.
4. ELISA assay
Table 3, charge six: ORI charged that Dr. Imanishi-Kari had
deliberately reported falsified evidence (I-1:83-88) to
investigators to support prior published research and that this
false reporting constituted scientific misconduct. Charge letter
at 7.
Issue: ORI found that Dr. Imanishi-Kari had falsified the ELISA
results for the Table 3 hybridomas by changing the date on I-1:83
(from 10/12 to 12/14) and by adding the notation in the heading
on that page (GP à 17.2.25 coat) to indicate that the assay was
done on a guinea pig anti-idiotype (anti-Id) coat, when in fact
the assay was done on a anti-immunoglobulin (anti-Ig) coat. ORI
relied on forensic evidence that the date was changed and that
the heading was added at a different time from the data. ORI
also relied on testimony from Dr. O'Toole that she had seen the
ELISA in May 1986 without the heading and had been told that this
was an isotyping assay on a rabbit anti-mouse immunoglobulin
(RAMIg) coat. ORI presented testimony from scientific experts
(primarily Dr. Dahlberg) about why they would conclude that the
ELISA was done on an anti-Ig coat, rather than an anti-Id coat.
Dr. Dahlberg also testified about why he thought data on idiotype
and NIP frequency in the January 1985 grant application were
inconsistent with the ELISA having been on an anti-Id coat.
Dr. Imanishi-Kari alleged that it does not matter when the
experiment was done or when the heading was added. She asserted
that the heading was correct, as shown by internal evidence in
the data, especially the controls. Dr. Imanishi-Kari denied that
Dr. O'Toole saw the ELISA in May 1986 and was told it was on a
RAMIg coat. Dr. Imanishi-Kari said that, as indicated in the
grant application, the frequency data ORI cited were from an RIA,
not from the ELISA, and that she would not have trusted the ELISA
for this purpose.
Analysis: The Panel concludes that ORI did not prove that the
ELISA was falsified. Specifically, we conclude that: (1) the
ESDA analysis does not show that the anti-Id heading was false;
(2) the experimental record and context support a conclusion that
this ELISA was done on an anti-Id coat; (3) Dr. O'Toole's
testimony on this issue is not credible; (4) ORI did not prove
that the controls were falsified; (5) ORI's scientific arguments
about the ELISA coat are based on faulty premises; and (6) the
date change on I-1:83 does not show that the ELISA was falsified.
We explain the basis for these conclusions below.
The ESDA analysis does not show that the anti-Id heading on
the ELISA was false.
Page I-1:83 has the heading "GP à 17.2.25 coat (Eliza J-K)."
This page and the next three pages are summaries of an ELISA with
isotype probes on supernatants of 146 hybridomas (some of them
tested twice). Pages I-1:87-88 are grids corresponding to wells
on a 96-well plate; some of the spaces on the grid have various
types of markings in what appears to be a gold marker pen (open
or closed circles--some of them smeared, + or +/-) or pluses in a
blue pen. Red marks indicate what parts of the grids relate to
tests for various heavy chains. Pages I-1:83-86 summarize these
results in columns with various heavy chain headings. Each well
was graded, with - meaning no color and other gradings (+/-, +,
++, or +++) according to the color intensity. Other columns
summarize some other data. Pages I-1:89-92 summarize isotyping
results for the same hybridomas on a companion ELISA presented as
being on a NIP-BSA coat.
After reviewing the entire original I-1 notebook, Dr. Weaver's
notebook, and all of the testimony and related documents, we
conclude that the ELISA summarized at I-1:83-88 was done on an
anti-Id coat, rather than on an anti-Ig coat.
We note first that ORI did not allege that the ELISA ever had a
heading showing that it was on an anti-Ig coat. ORI alleged that
ESDAs of page I-1:84 indicate that the heading was put on the top
line of I-1:83 at a "later time" than the data (or as Dr.
Dahlberg also put it "after the inquiry process was initiated,"
implying that it was added after the Wortis meeting). Tr. 443,
446. As discussed above, the ESDA analyses are very limited
and cannot determine whether the heading was added before or
after the rest of the data, or how soon before or after. See Tr.
3322 (Hargett). Contrary to what Dr. Dahlberg stated, the Secret
Service did not find that I-1:83 and 84 were in registration when
the data on the hybridomas were entered. Tr. 447-48 (Dahlberg).
Mr. Hargett testified merely that the heading was done in two
separate movements or at two different times and that the heading
was put on separately from the body of the page. Tr. 3322, 3532.
After examining the ESDAs, we find that: (1) the eight column
headings for isotype are in registration (possibly entered when
the pages were on the same pad); (2) the data entries for the
hybridomas are not in registration; (3) when the "GP à 17.2.25
coat" was entered, I-1:83 and 84 were in a position relative to
each other that was close to registration; and (4) the pages were
clearly out of registration when "(Eliza J-K)" was entered.
Thus, the forensic evidence is consistent with the coat heading
being added at the same time as the data; at most, the evidence
supports an inference that the heading and the data were added
after the column headings and after the page was torn off the
pad. In any event, no matter when the heading was added, the key
issue is whether it is false.
The experimental record and context support a conclusion
that this ELISA was done on an anti-Id coat.
The experimental record and context support a conclusion that
this ELISA was done on an anti-Id coat, for the following
reasons:
The protocol for the ELISA appears on I-1:94. ORI did not
question this page. The protocol is in pencil and is
unreadable on the xeroxed copies. The protocol states:
Test on Eliza J-K AP Ab on à 17.2.25.
96 wells supernatants (Tereza's sup)
Test also on NIP-BSA plates.
Thus, unchallenged entries directly support the way both
ELISAs (anti-Id and NIP-BSA) are presented.
ORI presented testimony to show that it would be a "logical
early step in the investigation of the panel of hybridomas"
to do isotyping on an anti-Ig coat. ORI Br. 109, citing Tr.
1494 (Gilbert). That it might be logical to do an assay one
way, however, does not make it illogical to do it another
way. Moreover, the following make it more plausible that
the ELISA would have been done on an anti-Id coat: (1) Dr.
Weaver had done an initial screening of the parent wells for
the hybridomas on an anti-Ig coat that showed virtually all
wells producing antibodies; (2) Dr. Weaver's experience with
pre-B cells created an expectation that all transgenic
hybridomas would express the transgene, and therefore that
an anti-Id coat would capture virtually all antibodies of
interest; and (3) Dr. Imanishi-Kari had screened the parent
wells for idiotype-positive antibodies, and the parent wells
for the vast majority of the hybridomas tested in the ELISA
were highly idiotype-positive. W-2:22-30 (unnumbered);
Tr. 5325 (Imanishi-Kari); I-1:11-21 (unquestioned pages).
The ELISA assay would have been very time-consuming, and the
results would have been difficult to read. (It is
undisputed that Dr. Imanishi-Kari did not have an ELISA
optical scanner, so she had to read the results by eye.)
Since Dr. Imanishi-Kari's primary interest was in idiotype-
positive antibodies and since the parent wells had been
prescreened, we think it unlikely that she would have done
such a complicated and difficult-to-read experiment on an
anti-Ig coat, when that would not have given her very useful
Dr. Reis testified that when she was in the laboratory, the
plate coatings mainly used were the anti-17.2.25 or the
antigen, and that they also sometimes used NIP or chicken
gammaglobulin. Tr. 2525. ORI proposed that we find that
anti-mouse Ig was "frequently in use" in Dr. Imanishi-Kari's
laboratory, but ORI's record citations do not support this.
ORI FFCL XI.C.iii.19. The only tests ORI cited were tests
using a goat anti-mouse Ig coat (not a rabbit anti-mouse Ig)
by Dr. Weaver, who did most of his assays in Dr. Baltimore's
laboratory. W-2:19-20; Tr. 2380 (Weaver).
Dr. Imanishi-Kari presented unrebutted testimony that the
control data on I-1:86 showed that the main assay was done
on an anti-Id coat, specifically, the use of a NIP coat for
the controls (which would not have been necessary if an
anti-Ig coat had been used), and the fact that no reaction
with the à probe was recorded for J558 (an à that is a
negative control for NIP). Tr. 1944-55 (Eisen), 2739-42
(Wortis), 2831-33, 2843 (Capra), 3126-29 (Marrack). Dr.
Imanishi-Kari's brief also pointed out that hybridoma
L3.13.3 tested positive for æ on a Weaver Northern blot
(with a result too strong to be a sterile æ transcript) but
negative on the ELISA, and these results are inconsistent
with the ELISA being on an anti-Ig coat. R. Br. 78, citing
Ex. H22, at 107. ORI did not address this point in its
The authenticity of the ELISA is further supported by the very
ambiguity of the heavy chain results on which ORI relied in part
in claiming that double producers existed. If Dr. Imanishi-Kari
was willing to tamper with the ELISA heading, she would certainly
have been more likely to remove the problematic results with the
heavy chain probes.
Dr. O'Toole's testimony on this issue is not credible.
ORI contended, however, that Dr. Imanishi-Kari was stuck with
this page and could make only small alterations because
Dr. O'Toole had seen it at the May 1986 Wortis meeting.
Specifically, Dr. O'Toole testified that (1) she remembered
Dr. Imanishi-Kari showing the ELISA during the Wortis meeting;
(2) the ELISA was represented as being on a RAMIg coat at that
meeting and at other meetings; and (3) after a discussion at the
Wortis meeting to the effect that idiotype-positivity and þ heavy
chains would have to be shown in the same assay to support the
Cell paper's claims and that the ELISA did not do this, Dr. Huber
had "groaned" and said this was a "serious problem." Tr. 989-91,
1051.
Even if things happened as Dr. O'Toole described them, we find it
hard to understand why Dr. Imanishi-Kari would risk falsifying a
coating reagent, but hesitate to change the heavy chain results
for a few critical hybridomas. In any event, we do not credit
Dr. O'Toole's claims that she saw the page without the coating
reagent and that Dr. Imanishi-Kari said that the ELISA was done
on a RAMIg coat. Our reasons are as follows:
As discussed above, there is internal evidence that the
ELISA was done on an anti-Id coat, and use of this coat
would be more consistent with the experimental record as a
whole.
After hearing Dr. O'Toole and the other witnesses testify
and examining all of her statements over the years, we
question the accuracy of Dr. O'Toole's memory and her
increasing commitment to a partisan stand. She had
previously asserted that she saw only two pages of data (I-
1:113 and 41) at the Wortis meeting. Tr. 1060-63. She did
not mention seeing the ELISA until after she likely had
heard about ESDA results, but attempted to explain this by
saying that questions about the ELISA simply did not arise
until later. Ex. H276; Tr. 1038-41, 1064-67. We find it
hard to believe that she examined the ELISA carefully enough
to notice the heading, but did not refer to the ELISA
results when positing her theory in her memorandum to Dr.
Eisen that idiotype-positivity was due solely to the
transgene. See H231, at 3.
No one corroborated Dr. O'Toole's testimony that
Dr. Imanishi-Kari had admitted at the Wortis meeting and
other meetings that the ELISA was on a RAMIg coat. Such a
statement clearly would have been against Dr.
Imanishi-Kari's interest. None of the other attendees at
the Wortis meeting recalled seeing the ELISA at that
meeting, and Dr. Imanishi-Kari denied showing it. Compare
ORI FFCL XI.C.iii.14 with Tr. 2802 (Wortis), 1787 (Huber),
4975 (Imanishi-Kari). Dr. O'Toole attempted to bolster her
assertion by referring to the coffee stain on I-1:87. Tr.
990. ORI pointed out that the stain is not visible in the
xeroxed copies, and Dr. O'Toole testified that she had not
seen the original since the Wortis meeting. Id. We find it
implausible that she never saw the original laboratory
notebooks during the many years she collaborated with ORI,
its predecessor, and the Subcommittee. In fact, she later
admitted under questioning that she had seen the originals
at the U.S. Attorney's Office and in meetings with either
OSI or ORI. Tr. 1074-75.
ORI asserted that, if the ELISA were on an anti-Id coat, it
would have been presented as such at the Wortis meeting to
respond to Dr. O'Toole's concern about whether there was
evidence of idiotype-positive þs (as what Dr. Gilbert called
"the killer experiment"). ORI Reply Br. 40. We find it
credible that the ELISA was on an anti-Id coat, but not the
focus of the Wortis meeting, for the following reasons: (1)
the participants of that meeting understood Dr. O'Toole to
be positing æ/þ heterodimers and countering this theory
would require evidence of hybridomas that were not only þ
positive on an anti-Id coat, but were clearly æ negative;
(2) the other scientists had found subcloning to be critical
in resolving the question of whether idiotype-positivity was
coming from þs or æs; and (3) Dr. Imanishi-Kari had reason
to regard the ELISA results as not definitive.
ORI did not prove that the controls were falsified.
ORI acknowledged that Dr. Imanishi-Kari's point about the
controls on I-1:86 was "scientifically correct." ORI FFCL
XI.C.iii.63. ORI attempted to counter this point with (1) Dr.
Dahlberg's interpretation that the control results were in a
particular place on the grid at I-1:88, and were not accurately
transcribed to I-1:86; and (2) his interpretation of the ESDA of
I-1:87. Dahlberg Decl. 11 and Att. 12; Tr. 6371, 6436
(Dahlberg). Neither of these interpretations is well-founded.
First, after comparing the summary data and grids, we reject Dr.
Dahlberg's interpretation that the last line of the lower
righthand grid on I-1:88 was for the controls, but the controls
were not accurately transcribed. This particular grid is
difficult to read because it is smeared, with smudges of gold
marker ink that suggest some recording of results that were not
highlighted with pluses in blue pen, and a few spaces with blue
pluses. An analysis of the pattern of the grids on I-1:87-88
overall, however, indicates that there are summarized data for a
set of 12 hybridomas for which there is no corresponding raw data
grid; there is one grid which corresponds to part of the kappa
light chain results; and there are lambda light chain results
summarized, for which there is no grid. There is nothing that
clearly connects the lower righthand grid or any part of it to
any of the summarized data, including the controls. Since the
summarized data that clearly correspond to extant grids are
accurately transcribed (as Dr. Dahlberg acknowledged), we see no
reason to posit that one part of the largely unreadable grid
corresponds to the controls but was not accurately transcribed.
Dahlberg Decl. 11.
Concluding that grids are missing for the controls does not
undercut Dr. Imanishi-Kari's position that the controls were done
as shown on the data summary on I-1:85. Some of the grids for
other results are missing (probably because they were destroyed
by the coffee spill evident on pages I-1:86, 87, and 88). Also,
the exact same controls are recorded at I-1:92 for the ELISA on
the NIP coat, and these controls include the J558. Moreover,
even under Dr. Dahlberg's theory about where the controls appear
on the grid, the notations would be consistent with the use of
six controls, including one for à, and the readable results
appear inconsistent with the pattern that would be expected if an
anti-Ig coat had been used.
Second, after carefully examining the ESDAs, we decline to infer
from the ESDAs that the box and the indication of NIP coat were
placed on I-1:86 after the page was originally created and that
some of the controls (including J558) were added at a much later
time than the other entries. ORI FFCL XI.C.iii.a.21, 24 and 25.
Page I-1:87 is one of the pages of raw data grids, recorded on a
type of paper different from the summaries, so there is no reason
to expect them to have been in registration during the
transcribing of various parts of the data. The ESDAs of I-1:87
show faint impressions of: (1) some of the data for heavy chain
probes and light chain probes, not in registration; (2) the
third, fourth, and fifth of the six control proteins listed on I-
1:86 (that were clearly needed no matter what the original coat
was); (3) the box that surrounds all six control proteins; and
(4) the arrow and "NIP coat" notation. The position of these
entries shows only slight movements of the two pages relative to
each other. The three control proteins are in the box, but not
in registration with each other or the surrounding box. The
impressions of the controls that do appear are very faint, thus
suggesting that other control entries simply made no discernible
impression. The box, which did appear in the impressions, was
drawn in a size and shape to fit the full set of controls.
As discussed above, ESDAs never indicate how much time has passed
between the recording of particular entries, nor do they always
reveal every entry made at the same time. Positing a meaningful
passage of time is even more tenuous if no entries are made on a
page while in registration with another page from the same pad.
The ESDAs here do not show any data being added to pages from the
same pad in registration. Nor do the ESDAs show only the
critical entries (the J558 control, the box around the six
controls, and the "NIP coat" notation) being added when pad page
I-1:86 was on top of grid page I-1:87, which would be more
consistent with ORI's scenario. The particular ESDA here is
consistent with a contemporaneous recording of the critical
entries. Thus, we decline to draw the inference of fabrication
of the controls that ORI would have us draw.
ORI's scientific arguments about the ELISA coat are not
supported.
We reject ORI's other scientific arguments about the ELISA coat
because they are based on ORI's questionable interpretations of
the data. We do not address all of the parties' rather
convoluted arguments on these questions. The key reasons we do
not adopt ORI's interpretations are as follows:
Dr. Dahlberg testified that the ELISA results on I-1:83-86
could not have been results on an anti-Id coat because they
are too similar to the ELISA results on the anti-NIP coat,
and this correlation is inconsistent with the frequency data
in Table 2 of the Cell paper. See Tr. 444-45, 449-50. He
subsequently acknowledged in effect that if the first part
were done on an anti-Ig coat, and the second part on an
anti-NIP coat, the results would be even less likely to be
so parallel. Tr. 6355. His reliance on the fact that the
Table 2 results did not show such high correlation between
NIP-binding and idiotype positive antibodies is misplaced,
because the tests were not on comparable sets of antibodies.
As discussed above, the Table 2 RIAs were on supernatants
from a complete set of pauci-clonal parent wells from a
fusion. These ELISAs were on supernatants from a set of
hybridomas derived from only four plates of multi-clonal
parent wells, and supernatants from the parent wells for
most of these hybridomas had previously tested positive for
both idiotype and NIP. I-1:11-21; Tr. 429-30 (Dahlberg).
Testimony by Dr. Imanishi-Kari and other expert witnesses
confirms that there are other plausible explanations of why
a correlation between idiotype-positivity and NIP-binding
might be higher in this experiment than in other
experiments, in particular, because different detecting
reagents were used. Tr. 1400 (Davie), 3129-30, 3152-53
(Marrack), 4736-41 (Imanishi-Kari); see also Ex. H299, at 3
(Storb).
Dr. Davie testified that he questioned the ELISA being on an
anti-Id coat because there are positive results in the tenth
(rightmost) column, testing the hybridomas with the
idiotype, and he questioned how one could have idiotype-
bearing antibodies that were also anti-idiotypic. Tr. 1375-
76, 1426-28. ORI asserted that this would be a startling
result that Dr. Imanishi-Kari would have mentioned in a
January 1985 grant application, but did not. Cf. ORI FFCL
XI.C.iii.42, 43. Dr. Imanishi-Kari presented convincing
evidence about why she would not have considered such a
result to be "startling." Tr. 2478-79 (Kearney), 2843-44
(Capra), 4730 (Imanishi-Kari); see also Tr. 2031 (Eisen).
Contrary to what ORI argued, the fact that she called the
results "interesting" does not mean she would have directly
referred to them in the grant application. The grant
application did report that she had detected 29 hybridomas
that reacted to the idiotype, and indicated her interest in
doing more work on whether the hybridomas would react with
various idiotype reagents. Ex. H6, at 141. This
application does not specifically state that 29 hybridomas
reacted to both idiotype and anti-idiotype reagents.
However, ORI's argument that she would have mentioned any
finding that some hybridomas were positive for both the
idiotype and anti-idiotype is undercut since the grant
application: (1) refers to findings in the ELISA that 29
hybridomas reacted to the idiotype; (2) lists four of these
hybridomas as reacting to the anti-idiotype; and (3) does
not mention the dual reactivity as a startling result.
Ex. H6, at 130; I-1:93-94.
Dr. Dahlberg testified that, if the ELISA was on an anti-Id
coat, all of the hybridomas scored positive on the ELISA
would be idiotype-positive and the frequency would be 80%,
which is much higher than the frequency reported in Table 2
of the Cell paper. Tr. 444, 456-61. This alleged
discrepancy is not significant, however, since: (1) the
Table 3 hybridomas were not a complete set of hybridomas,
but only a subset grown from four thawed plates, and most of
the subset came from idiotype-positive, multi-clonal parent
wells; (2) reading the ELISA by eye required judgment; (3)
Dr. Dahlberg calculated frequencies for the ELISA by
considering hybridomas that scored as merely + or +/- as
hybridomas that "scored positive" on the ELISA.
Dr. Dahlberg also suggested that, if the ELISA was done on
an anti-idiotype coat, Dr. Imanishi-Kari would have reported
in the Eisen grant application the 80% idiotype positivity
shown on the ELISA, rather than the numbers from an RIA
indicating 40% idiotype positivity. Tr. 456-57. Given the
judgments involved in reading the ELISA by eye and the
ambiguous results shown for it, however, we find credible
Dr. Imanishi-Kari's assertions that she considered the ELISA
less reliable for this purpose than the RIA. Moreover, if
only the approximately 70 hybridomas with +++ results on the
ELISA for at least one heavy chain are counted as positive
for idiotype, the ELISA results are not significantly
different from the results in the grant application.
Finally, we find that, in determining that the ELISA was a test
for isotype only, ORI placed too much weight on Dr. Weaver's
statement in June 1990 that "the isotype analysis preceded the
idiotype analysis which preceded the allotype analysis . . . . "
Ex. H116, at 29. This statement does not address the issue of
what coat was used for any isotyping work. Moreover, Dr. Weaver
noted that he did not do the serological work, that this was just
his recollection, and that he was not sure. Ex. H116, at 29-30.
The date change on I-1:83 does not show that the ELISA was
deliberately falsified.
Based on Secret Service analyses, ORI alleged that Dr. Imanishi-
Kari had falsified the date on I-1:83. Mr. Hargett testified
that he found that "what appears to be a 12 for the month was
really a 10, appears to be a 10" and that it was his opinion that
the date was altered from a 10 to a 12. Tr. 3321-22 (Hargett),
3674-75 (Stewart). Dr. O'Toole testified that the date was not
on the page when she saw it in May 1986. Tr. 991.
We first note that, as Mr. Hargett acknowledged, the date change
from 10/12 to 12/12 is "obvious." Tr. 3533-34 (Hargett). The
ORI Report questioned why, if Dr. Imanishi-Kari did the ELISA on
an anti-Id coat in October, she would not have reported it in the
grant application submitted October 31. ORI Report 157. The
implication was that she had a motive to falsify the date because
she falsified the anti-Id coat heading, and then needed to
explain why she did not report the ELISA in the October
application. This motive depends on the allegation of
falsification of the heading, which we rejected above. Moreover,
the ESDA of I-1:84 shows both the "GP à 17.2.25 coat" heading and
the 10/12 date, but not the date change, so this theory is
questionable.
Dr. Imanishi-Kari testified (apparently based on the protocol on
I-1:94 for the ELISA on the idiotype coat reported in the tenth
column on I-1:83-86) that it is possible that she did the main
assay in October and the assay on the idiotype coat in December.
Tr. 5214-20. We do not need to resolve this question because ORI
did not prove that it is more likely that the date change was a
deliberate falsification, than an honest change. We note,
however, that the following indicate that the ELISAs may have
been done or summarized in December: (1) the protocol has a
12/12 date; (2) the 12/12 "Summary of Subcloning" at I-1:80-82
does not mention ELISA results; (3) the notation in red ink on I-
1:86 ("Subclone again the circle over") may indicate she had
already done some subcloning; and (4) the date on the protocol on
I-1:95 for subcloning the circled hybridomas (which is in red
ink) is 12/14.
ORI relied on similar obvious date changes for the NIP-coat ELISA
to bolster its arguments. Specifically, ORI relied on
indentation analyses which ORI said showed that I-1:89 was
"produced prior" to I-1:32-34, which were dated 10/30 to 10/31.
ORI FFCLs XII.C.xi.1-6. The indentation analyses show the
opposite, however. Ex. H500, at 2. Thus, contrary to ORI's
assertion, the indentation analysis is consistent with the
December dates.
The Panel concludes that ORI did not prove charge 6, Table 3, by
a preponderance of the evidence.
D. Other charges
1. I-1 Notebook
I-1 Notebook, charge one: ORI charged scientific misconduct,
alleging that Dr. Imanishi-Kari deliberately created, compiled,
and reported certain fabricated and falsified data in the I-1
Notebook. Charge letter 7.
Issue: In addition to the specific pages discussed above, ORI
asserted that there were other pages of the I-1 notebook which
were fabricated or falsified. ORI relied on the forensic
document examination and statistical evidence for the pages that
we have already discussed with regard to allegedly fabricated or
falsified pages as well as on document examination and
statistical evidence generally for certain additional pages of
the I-1 notebook.
Analysis: ORI asked us to conclude (1) that Dr. Imanishi-Kari
was attempting to create an experimental record that was more
convincing than it actually was (ORI FFCL XII.E.6); and (2) that
the scientific, forensic, and statistical evidence presented as a
whole supports a conclusion that at least 33% of the I-1 notebook
was falsified or fabricated with respect to time (ORI FFCL
XII.F.1.). To buttress its assertion as to the overall
fabrication and falsification of many pages of I-1, ORI relied on
its assertions that there was no scientific basis for the
serological results reported in the Cell paper.
In our analyses of ORI's allegations related to the Cell paper,
we have rejected many of the specific allegations related to
pages of the I-1 notebook that are also included in this charge.
We have discussed at length the complex questions of
interpretation of scientific data raised by ORI's charges and by
its evidence. We have also discussed at length why we found
unpersuasive the results of the various documentation and
statistical techniques employed to analyze the pages of the I-1
notebook. With regard to the additional pages added in this
charge, ORI relied on the same types of forensic findings. Even
if true, these forensic findings are not sufficient to prove the
fabrication and falsification charged. For reasons analogous to
those explained at length earlier, we conclude that the forensic
evidence adduced by ORI is simply not probative of its charge.
The Panel concludes that ORI did not prove charge one related to
the I-1 notebook by a preponderance of the evidence.
2. Letter of Correction
Letter of Correction, charges one and two: ORI charged that
Dr. Imanishi-Kari included in Table 1 of the Letter of Correction
(Ex. H3) data that were fabricated to establish the specificity
of BET-1. In addition, ORI charged that the data presented in
Table 2 of the Letter of Correction (on selected hybridomas from
the primary wells reported in Table 2 of the Cell paper) were
also fabricated. Charge letter 8.
Issue and analysis: These charges were entirely based on
allegations that the underlying data at I-1:121 and I-1:124-128A
(June subcloning) were fabricated. We discussed and rejected
these allegations in our analysis on Figure 1 and Table 2 of the
Cell paper. Therefore, we summarily reject these charges.
The Panel concludes that ORI did not prove charges one and two
related to the Letter of Correction.
3. Grant applications
Grant Applications, charges one and two: ORI charged that
Dr. Imanishi-Kari committed scientific misconduct by deliberately
making false and misleading statements in two grant applications
-- 1 RO1 AI22632-01 and 2 PO1 CA28900-06. Charge letter 8-9.
Issues: ORI charged that these applications, one of which was
funded, contained deliberately "false discussions of idiotype-
specific hybridomas in transgenic mice that were material and
critical to the grant applications." ORI Br. 118.
Analysis: It is undisputed that intentional falsification of
material statements in a grant application would be scientific
misconduct. See DAB 1431, at 2 (1993). Here, the allegations
relating to the grant applications are largely subsidiary to the
primary charges relating to the Cell paper and the I-1 notebook.
The applications did not receive close scrutiny until relatively
recently; we regard these allegations as largely an afterthought
to add additional weight to support the proposed ten-year
debarment and other administrative actions should the primary
charges be upheld. On the whole, the grant application charges
derive either from the rejected Cell paper charges or an overly
harsh parsing of the application text. While the language
excerpted by ORI suffers generally from the same type of
imprecision we saw in the Cell paper, we reject ORI's charges of
deliberately false and misleading statements in general
because --
some charges rely on an unreasonable reading of particular
language or on only one possible reading of ambiguous
language that in context is better read in another way; and
some charges derive from charges of fabrication and
falsification related to the Cell paper, which we concluded
above were not substantiated.
We discuss each of the applications below.
ORI did not prove that Dr. Imanishi-Kari deliberately made
false and misleading statements in Grant Application 1RO1
A122632-01.
This application, "Regulation of Idiotype Expression," was
submitted on October 31, 1984 and funded for $68,252 in direct costs. Dr. Imanishi-Kari admitted in her response to the charge that she prepared this application and was responsible for its contents. Stips. 30, 40; Tr. 5496, 5498-99. The disputed text appears as part of the "[P]reliminary results and background studies" section following research proposed to "[d]etermine whether expression of a particular heavy chain on the surface of B cells disrupts the normal T and B cell repertoire." ORI asserted that this text was material to the decision to fund the application. The disputed text, with the allegedly falsified parts in bold and designated by capital letters, states as follows -- Spleen and lymph nodes of mouse 54.28.5 as well as from normal littermate mouse [A] was fused to HAT sensitive myeloma X63.6.5.3. Hybrids were subcloned and analyzed [B] for NIP binding as well as for 17.2.25 idiotype. The number of hybrids obtained from normal littermate spleen and lymph nodes were the same as that obtained from mouse 54.28.5. Some of the hybrids of normal littermate, did secrete anti-NP antibodies associated with [kappa] light chains, however, none expressed 17.2.25 idiotype. [C] The results obtained from the analysis of 37 hybridomas from 54.28.5 mouse is shown in table 2. There were 10 hybrids that bound strongly to NIP hapten and had [kappa] light chains and two were [lambda]1 light chains. . . . [D] We first discuss each of the allegedly false statements, and then discuss ORI's general argument that these statements were material to the decision to fund the application. A. ORI asserted that the reference to a normal littermate mouse fusion was falsified since Dr. Weaver's notebook contained no contemporaneous normal mouse fusion during the spring of 1984 when he conducted the transgenic fusion. ORI Br. 119; ORI FFCLs XIV.A.7, 15. However, we find that the disputed text neither states nor infers that Dr. Weaver carried out a contemporaneous normal fusion; moreover, as noted by Dr. Imanishi-Kari, there were clearly normal fusions appearing in her data books prior to the submission of the grant application, such as the one at I- 1:3-5. We find Dr. Imanishi-Kari's assertion that the specific normal assays referred to in the application were no longer available to be reasonable under the circumstances. We find that ORI presented no credible reason why Dr. Imanishi-Kari would deliberately misrepresent work done on normal mice. Since the application was submitted in October 1984 by Dr. Imanishi-Kari, who worked with Dr. Weaver on the fusions, and who carried out independent work on fusion assays, there is no reason to read her grant application as referring only to data now in Dr. Weaver's notebook. B. ORI asserted that this statement was false since the "data were not obtained from subcloned hybrids," and that Dr. Imanishi-Kari had misrepresented her work as further along than it was since the underlying data reported in the application corresponded absolutely with the data at I-1:12-21 (a rescreen dated August 24, 1984 of Dr. Weaver's original 24-well plates (dating from April and May of 1984)). ORI Br. 119-120. Dr. Imanishi-Kari attributed the alleged falsification to confusion as to her use of the terms clone and subclone. While there is certainly confusion in terminology manifested throughout this record, we find that the charge for this statement is also based on a misreading of the sentence itself. The sentence at issue states that the "Hybrids [parent wells] were subcloned and analyzed . . ." The sentence does not state that the subcloned (or cloned) hybrids were analyzed. The underlying experimental data, which ORI acknowledged are accurately presented, are for the parent wells. Therefore, while the wording of the disputed sentence is not particularly well-drafted, we find no reason to read the sentence as ORI does to refer to data on subclones. We resolved above allegations of scientific misconduct related to use of the term hybridomas when referring to the cells in a parent fusion well. This common laboratory jargon also appears in the application. Thus we conclude that the wording of this sentence is confusing, not deliberately falsified. C. ORI asserted that this sentence was false because "Dr. Weaver did not carry out a fusion with spleen and lymph nodes of a normal mouse in parallel with his fusion of the M95.18 mouse." ORI Br. 120; ORI FFCL XIV.A.4. As Dr. Imanishi-Kari noted, the application does not represent that the fusion was contemporaneous or represent that the underlying data are from Dr. Weaver's notebook. Therefore, we reject this allegation since the fact proved by ORI does not show that the representation in the application was false. D. ORI asserted that this statement is false and misleading because the quantitative results claimed were not obtained by Dr. Imanishi-Kari" since I-1:20-21 shows that the results given for hybridomas were for parent wells not for clones. ORI argued that Dr. Imanishi-Kari knew that because the data were "derived from multi-clone wells, the numbers reported are clearly inaccurate and overstated." ORI Br. 120-121; ORI FFCLs XIV passim. We have discussed above the Table 2 Cell paper charges related to the "hybridoma" wells versus clones issue. We similarly reject the charge that this term is used here intentionally to mislead. The application statement is clearly imprecise. However, the laboratory jargon "hybridomas" when referring to parent wells was used even in the Cell paper. The grant application text does not purport to report on definitive results. Furthermore, Table 3 of the application, which displays the data on the 37 "hybridomas," uses the nomenclature for the parent wells, i.e., L3-1, L3-2, L3-2 etc. We do not find it credible that Dr. Imanishi-Kari would deliberately misrepresent her data by using the term hybridoma yet accurately display her parent well data and the nomenclature in the associated table. ORI also argued that the disputed language was material to the decision to fund this application. ORI asserted that it "seems very likely that the [alleged] misrepresentations contributed to the favorable review." ORI Br. 121. ORI's argument makes only a speculative connection between the disputed statements and the favorable review. ORI relied on the laudatory comments made by the NIH Study Section, which, it is undisputed, were highly complimentary. Tr. 1648-50 (McClure). The Study Section opined that the proposed study of NP gene expression in collaboration with Dr. Baltimore's group was "extraordinary." Ex. H5 (Summary Statement at 3). The Study Section comments do not rely specifically on the statements at issue and state that the "vital task is the sequencing and identifying of the Vh genes expressed". Id. The Study Section emphasizes the collaborative efforts on the molecular work with Dr. Baltimore. Thus, ORI's reliance on the favorable review to show materiality of the disputed language is misplaced. The Panel finds that ORI did not prove that Dr. Imanishi-Kari deliberately made false and misleading statements in the October 1984 grant application. ORI did not prove that Dr. Imanishi-Kari deliberately made false and misleading statements in Grant Application 2 PO1 CA28900-6. This application, "Control of Antigen-Specific T-cell Responses" was dated January 31, 1985; Project III was prepared by Dr. Imanishi-Kari and was not funded. The disputed text is part of the description of a table and appears in the portion of Dr. Eisen's application that was prepared by Dr. Imanishi-Kari. Ex. H6, at 130. ORI also charged that portions of Dr. Imanishi-Kari's Figure 1 were "false, fabricated, and misleading." ORI Br. 123-124. Table 3 presents data on 11 hybridomas (not from parent wells), some of which are included in Table 3 of the Cell Paper. The disputed text for Table 3, with the allegedly deliberately falsified material in bold, is -- . . . This table is depicting only the most representative hybridomas obtained from the lymph nodes and spleen of a transgenic mouse. Out of a total of 150 hybrids analyzed, 40 were [kappa]-bearing NIP and 17.2.25 positive, and 11 were 17.2.25 positive non-NIP binders; 9 were [lambda]- bearing NIP and 17.2.25 positive. There were 34 hybrids that were [kappa]-bearing NIP binders but non-idiotype 17.2.25. . . . . Out of 150 hybridomas only one may be expressing the exogenous gene. . . . ORI argued that the phrase "most representative" was deliberately falsified because it represented the hybridomas in the table as a "population of representative hybridomas obtained at random from a mouse . . . rather than only a limited population of 150 hybridomas representing sets of clones obtained from just 29 wells of a fusion." ORI FFCL XIV.B.9. Dr. Imanishi-Kari argued that the language simply means that she was presenting some of the results obtained. R. Br. 91. In light of the complexity and difficulty of these types of assays, it is unclear whether one could ever obtain a representative sample of hybridomas such as ORI described. Therefore, we reject ORIs strained reading to support its charge. ORI also asserted that there were 146 clones, not 150 and that Dr. Imanishi-Kari's description infers that 150 have been completely analyzed, with only one expressing the transgene. While the disputed language is no model of clarity, ORI's assertion of deliberate falsification goes too far. As Dr. Imanishi-Kari pointed out, her discussion in the text, while not well-drafted, makes it reasonable to infer that her point is that only one of those analyzed "so far" for mRNA is expressing the transgene. The text does not assert that all the work was complete; indeed, Dr. Imanishi-Kari indicated that another application covered funding requested to do such further analysis. Therefore, despite ORI's urging, we decline to infer simply from the general references to analyses of the 150 hybridomas that Dr. Imanishi-Kari was representing that all the work on these hybridomas was complete and only one expressed the transgene. In addition, ORI did not provide evidence that Dr. Imanishi-Kari did not have some additional hybridomas from this fusion besides the 146 tested in the ELISA. Therefore, there is no reason to find the reference to 150 to be false. On balance, the other alleged deliberate falsifications are properly described as imprecise language not reasonably read to be deliberate falsification. ORI also raised in its proposed FFCLs the allegation that Dr. Imanishi-Kari's "claim that the data in Table 3 was obtained using RIA is false." ORI FFCL XIV.B.7. ORI asserted that "Dr. Imanishi-Kari has presented no data to support the claim in Table 3 . . . that 40% of the clones tested positive by RIA." ORI FFCL XIV.B.7. ORI stated that the Table 3 results show a different percentage (40%) of the hybridomas to be idiotype positive than the ELISA data at I-1:83-88 (80%). ORI discounted Dr. Imanishi-Kari's statement that both show a high percentage of idiotype-positivity as supporting her position that both experiments were done. This allegation goes beyond the charges stated in connection with the grant applications; therefore, we reject it summarily. We note, however, that ORI argued that Dr. Imanishi-Kari was obliged to maintain and provide these RIA data in 1988 upon request. It is not clear to which request ORI refers, since we do not read the Dingell request cited above to cover data underlying the applications. Moreover, the data pertain to a 1985 application which was not funded. While ORI stated that any such RIA was related to an earlier grant, ORI provided no evidence that the three-year record retention requirement applied, or that, if it applied, it would not have expired by 1988. See 45 C.F.R. 74.20-22. Thus, the requirement does not support any inference adverse to Dr. Imanishi-Kari from the unavailability of such data. We also note that, as we discussed above, ORI calculated the 80% idiotype-positivity on the ELISA by treating +/- and + as positive scores, which is a questionable interpretation of that assay. ORI also asserted that Figure 1 (Ex. H6, at 131) of the grant application was deliberately falsified. This figure contains four panels showing analyses of sera from normal and transgenic mice. This figure is at I-1:68. ORI asserted that Figure 1 was deliberately falsified since some experimental data at I-1:50 are the same as the graph in some respects, but different in others. ORI said that Figure 1 was deliberately falsified by adding four data points representing a fifth dilution and by misplotting several points. Dr. Imanishi-Kari asserted that Figure 1 was based on data other than I-1:50 and that the similarity between I-1:50 data and the Figure 1 graph (and I-1:68) is not surprising since Figure 1 contained percentage binding data, not actual counts, and was a reassay. ORI did not rebut Dr. Imanishi-Kari's testimony concerning significance of the use of percentage binding rather than specific counts per minute. See ORI Br. 123- 24; ORI FFCLs XIV.B.18-24. ORI advanced no reason why Dr. Imanishi-Kari would deliberately misrepresent the Figure 1 data. Therefore, we find no reason to conclude that Figure 1 was deliberately falsified. The Panel concludes that ORI did not prove either charge one or charge two related to certain grant applications by a preponderance of the evidence. CONCLUSION For the reasons explained above, we conclude that ORI did not prove by a preponderance of the evidence that Dr. Imanishi-Kari engaged in scientific misconduct as charged. We conclude that ORI's findings are not supported and the proposed administrative actions are not justified. We recommend no debarment. ___________________________ Judith A. Ballard ____________________________ Dr. Julius S. Youngner ___________________________ Cecilia Sparks Ford Presiding Panel Member Senior Staff Attorneys assigned to case: Leslie A. Sussan Jeffrey A. Sacks Appendix A Witnesses for ORI: John E. Dahlberg, Ph.D., Senior Scientist Investigator, Office of Research Integrity, Public Health Service. James E. Mosimann, Ph. D., Adjunct Professor, The American University, Department of Mathematics and Statistics. Austin M. Barron, Ph.D., Associate Professor, The American University, Department of Mathematics and Statistics. Margot O'Toole, Ph.D., Staff Scientist, Genetics Institute, Cambridge, Massachusetts. Joseph M. Davie, M.D., Ph.D., Vice President, Department of Research, Biogen, Inc., Cambridge, Massachusetts. Walter Gilbert, Ph.D., Carl M. Loeb University Professor, Department of Cellular and Developmental Biology, Harvard University. William R. McClure, Ph.D., Professor, Department of Biological Sciences, Carnegie Mellon University. John W. Hargett, Chief Document Examiner, Forensic Services Division, U.S. Secret Service, U.S Dept. of the Treasury. Larry F. Stewart, Senior Document Examiner-Instrumental Analysis Section, Forensic Services Division, U.S. Secret Service, U.S. Dept. of the Treasury. Charles Maplethorpe, Ph.D., Medical Officer, Center for Biologics Evaluation and Research, Food and Drug Administration, Public Health Service. Leiko Dahlgren, Ph.D., Tech Services Team Leader, Beckman Instruments. Witnesses for the Respondent, Thereza Imanishi-Kari, Ph.D.: Thereza Imanishi-Kari, Ph.D., formerly Research Associate, Tufts University School of Medicine. Robert T. Woodland, Ph.D., Associate Professor of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester, Massachusetts. Brigitte T. Huber, Ph.D., Professor of Pathology, Tufts University School of Medicine. Martina E. Boersch-Supan, Ph.D., Freelance Translator and Scientific Editor. Herman N. Eisen, M.D., Professor Emeritus, Department of Biology; Senior Lecturer, Center for Cancer Research, Massachusetts Institute of Technology. David Baltimore, Ph. D., Ivan R. Cottrell Professor of Molecular Biology and Immunology, Massachusetts Institute of Technology. Terence Paul Speed, Ph.D., Professor, Department of Statistics, University of California, Berkeley. David T. Weaver, Ph.D., Associate Professor, Dana Farber Cancer Institute. Martin E. Dorf, Ph.D., Professor of Pathology, Harvard University Medical School. Susan L. Swain, Ph.D., Professor, Department of Biology and Cancer Center, University of California San Diego. John F. Kearney, Ph.D., Professor of Microbiology, University of Alabama at Birmingham. Norman W. Klinman, M.D., Ph.D., Member, Scripts Institute; Adjunct Professor, University of California San Diego. Moema H. Reis, Ph.D. Christopher Albanese, Supervisor, Laboratory of Molecular Biology and Molecular Medicine, Northwestern University Medical Center. Henry H. Wortis, M.D., Director, Division of Immunology; Professor, Department of Pathology, Tufts University School of Medicine. J. Donald Capra, M.D., Director of Molecular Immunology Center; Professor of Microbiology and Internal Medicine, University of Texas Southwestern Medical Center. Edward B. Reilly, Ph.D., Research Investigator, Abbott Laboratories, North Chicago, Illinois. Philipa Charlotte Marrack, Ph.D., Investigator, Howard Hughes Medical Institute; Professor, Department of Microbiology and Immunology, University of Colorado Health Services Center. Gerald B. Richards, Independent Forensic Scientist, Richards Forensic Services; Adjunct Professor, Forensic Science Department, George Washington University. Elliott W. DeHaro, Billing Manager, Center for Cancer Research, Massachusetts Institute of Technology. Robert L. Kuranz, Forensic Ink Analyst. Reynold Verret, Ph.D., Associate Professor, Department of Chemistry, Clark University. Vivien Igras, Research Technician, Dana Farber Cancer Institute. William P. Fitzgerald, Sales Representative, Robin Scientific Corporation, Sunnyvale, California. 1. A debarment is an exclusion from eligibility for federal grant (non procurement) and contract awards for a specified period of time. A finding that a cause for debarment exists does not mandate debarment. Debarment is a discretionary, not punitive, action taken to protect the public interest. Gonzalez v. Freeman, 334 F.2d 570 (D.C. Cir. 1964); 45 C.F.R. 76.115 and 48 C.F.R. 9.402(a) and (b). 2. The guidelines permit appointment of an unbiased and disinterested scientist or other expert to the Panel. 3. See Appendix for a list of witnesses. 4. In proposed findings of fact and conclusions of law (FFCLs) submitted after the hearing, ORI misstated the evidentiary standard in this case, by suggesting that merely a "proposed finding" by ORI was sufficient to shift the burden to Dr. Imanishi-Kari to rebut the finding with credible evidence. ORI FFCL I.A.6. A shift in burden of proof (as distinct from a burden of going forward) occurs only after a prima facie case is presented, and such a case must itself be made based on reliable, credible, probative evidence. Here, much of the evidence which ORI presented does not meet this test. For the most part, ORI relied on its findings, from which it asked us to draw a particular inference. ORI sometimes failed to prove the factual basis for the inference ORI asked us to draw. Other times, ORI failed to demonstrate that the inference was a reasonable one in light of the proven facts, or failed to show that other equally reasonable inferences, in Dr. Imanishi-Kari's favor, should not be drawn, based on the evidence as a whole. 5. The history of the matter now before us has been long, tangled, and heated, stretching over more than a decade. We do not attempt a comprehensive exposition nor do we undertake to resolve all the disagreements among various participants about events and motives. Rather, we set forth here only a summary of the facts needed to understand the conclusions that we have reached about the charges before us, as we find them based on our review of the entire record. 6. The Cell paper was initially submitted in December 1985 and accepted after revision in February 1986. Stip. 41. 7. During 1984 to 1986, when the Cell paper research was done, the National Institutes of Health (NIH) awarded grants totaling$207,971 to Dr. Imanishi-
Kari as principal investigator. Stips. 22, 23, 32, 33, 40.
8. Dr. Imanishi-Kari left MIT in July 1986 and moved to Tufts University
where she remained until December 1994. ORI FFCLs III.G.1, 2.
9. This research on antibody production in B-cells followed earlier work in
Dr. Baltimore's laboratory which indicated that the transgene was expressed
without exception at the pre-B cell stage.
10. Antibodies are composed of light and heavy chains. Both light and
heavy chains can be found in a variety of types, known as isotypes. The two
types of light chain are kappa and lambda. The heavy chain isotypes of most
relevance to the Cell paper are æ (mu), þ (gamma), and à (alpha).
Characteristic forms of the heavy chain isotypes, called allotypes, can be
identified in inbred strains of mice. The allotypes of interest in the Cell
paper were for the æ heavy chain. The BALB/c mice, from which the transgene
was derived, expressed the æa allotype, while the C57BL/6 mice normally
expressed the æb allotype. An additional attribute of individual antibodies
that is of interest here is idiotype, which may vary even among antibodies of
the same isotype. The idiotype refers to structural features of the antibody
and can be defined by other antibodies which react to one or more of those
features or determinants. The idiotype of the transgene was called 17.2.25
and could be detected by anti-idiotype antibodies.
11. The serological work reported in the Cell paper involved primarily the
products of fusions, in which B cells from the spleen and lymph nodes of mice
(which may produce antibody) were fused with myeloma cells (which have the
capacity for unlimited replication) in an effort to create hybridomas which
are immortal and produce antibodies.
12. The procedure used in these experiments (and elsewhere in the Cell
paper) is a "sandwich assay," which essentially involves a coating reagent
adsorbed to a plate, to which the supernatant or sera of interest is added,
and then a reagent of some kind (depending on what is being studied) is used
as a probe to determine the extent to which the supernatant or sera bound to
the coat (was "captured"). If the probe is labelled with radioactive iodine,
the binding can be measured by a device called a gamma counter which counts
radioactive emissions, i.e., a radioimmunoassay (RIA). Alternatively, an
assay system can use an enzyme coupled to the antibody to detect binding,
i.e., enzyme-linked immunosorbent assay (ELISA). ELISA assays can be read by
eye based on the intensity of the resulting color change or by an optical
scanning device. Dr. Imanishi-Kari did not have such a device during the time
period relevant for this case.
13. Dr. Constantini was not involved in the drafting of the Cell paper but
rather developed and supplied the strain of transgenic mice. Stip. 19; ORI
FFCL VIII.A.4.
14. The group included, among others, Drs. Huber, Woodland, Wortis,
Imanishi-Kari, and Broder (Dr. O'Toole's husband, who was at Tufts
University). Tr. 1747 (Huber); ORI Br. 24, n.8.
15. The charge was to "(1) determine whether the published paper is
scientifically accurate, based on the original data; (2) if inaccuracies are
found, describe the nature and extent of the inaccuracies in the published
paper, including a statement as to whether misrepresentation or other
misconduct is involved; and (3) recommend appropriate corrections in the
scientific literature, if inaccuracies are found." Ex. H262 (NIH Scientific
Panel Report at 1).
16. Dr. Imanishi-Kari compiled her records into a binder referred to as
the "I-1 notebook."
17. Two additional scientists joined the NIH Scientific Panel members in
serving as advisors: Dr. Stewart Sell and Dr. William R. McClure.
18. ORI stated that if the I-1 notebook was authentic, "its component
parts existed in 1986 and should have been enough to satisfy Dr. O'Toole that
her concerns about the experimental support for the Cell 45 Paper were largely
groundless." ORI Br. 23. Yet, since the forensic results are inconclusive,
ORI often depended on its interpretation of the notebook data to buttress its
conclusions. This compelled us to address scientific issues, to evaluate ORI
allegations.
19. Thus, for example, the Customs Court wrote that --
our concern here is with the quality of the evidence in the record. In
ascertaining the proper weight to be accorded to the various reports and
affidavits, which were received in evidence in this case, no
significance can be attached to the mere number of such reports and
affidavits that one party or the other may have adduced in support of
their respective contentions.
D.C. Andrews & Co., Inc. v. United States, 1963 WL 9768, at *5 (Cust.Ct. March
5, 1963). We strove here to avoid the error, which has been observed to be
common among advocates, of confusing "quantity of evidence with probative
quality." United States v. Reaves, 636 F. Supp. 1575, 1579 (E.D.Ky. 1986);
accord United States v. Hildebrand, 1996 WL 262823, No. CR 95-2014 (N.D.Iowa
May 16, 1996).
20. ORI also submitted 272 pages of proposed findings of fact and
conclusions of law, numbering in the thousands. We have not addressed each
proposed FFCL individually in this decision for the same reason. However, we
carefully reviewed each and every FFCL in light of the record as a whole.
Many of the proposed FFCLs are undisputed, are irrelevant in light of the way
we have resolved the issues in this case, misstate evidence in the record, or
are implicitly rejected in our discussion. Where we found the substance of a
proposed FFCL supported by the evidence in the record as a whole and necessary
to the resolution of the issue, we reflect the substance of the FFCL in the
text of the decision but do not necessarily refer to the numbered proposed
FFCL.
21. We note that testimony before us from Dr. Davie (as well as from some
of ORI's other scientific experts) was based on the assumption that the Secret
Service conclusions about the authenticity of the I-1 notebook were well-
founded and on accepting information in the ORI Report as accurate. See,
e.g., Tr. 1312, 1392 (Christ), 1505 (Gilbert) and 1576, 1635 (McClure).
22. For example, in regard to two pages of data (I-1:41 and I-1:43), ORI
claimed they were fabricated to support Dr. Imanishi-Kari's claims that
certain hybridomas were idiotype-positive, yet stated that the data on those
pages were equivocal as to some of the challenged hybridomas and better for
some that were not at issue. See ORI Reply Br. 96. ORI acknowledged that
these results "do not show as positive a story as one would expect" if they
were fabricated to support Dr. Imanishi-Kari's claims, but suggested that this
might "simply reflect haste" in the fabrication process. ORI Br. 96, n.72.
It is hard to see why haste would explain faking less than helpful results --
it is as easy to put down a "good" number as a bad one for a hybridoma likely
to be important to Dr. O'Toole's challenge. Similarly, the "June subcloning
data," discussed in relation to charges concerning Table 2 of the Cell paper,
were allegedly fabricated very late in the process (possibly even during a
1988 NIH visit to interview Dr. Imanishi-Kari, according to ORI), yet they
present results that were inexplicable at the time (although undisputed
testimony indicates that they may have been explained by later scientific
work). Cf. ORI Br. 62-63; Respondent's (R.) Br. 55-56. Haste does not
explain creating new scientific questions.
23.
ORI argued that Dr. Imanishi-Kari was constrained by the need to fit her
fabrications to the unchallenged data and to the data on pages she had already
shown to Dr. O'Toole soon after she raised her concerns. ORI's Reply Br. 4-5.
These alleged constraints, however, really do not explain why Dr. Imanishi-
Kari would not have discarded any unfavorable or inconsistent pages that were
not shown to Dr. O'Toole, especially if Dr. Imanishi-Kari were undertaking the
sort of wholesale laundering of the record that Dr. O'Toole has alleged.
Furthermore, such constraints would not explain why Dr. Imanishi-Kari would
not, at least, ensure that the data that she did fabricate were uniformly
helpful. ORI argued that the allegedly false data were good enough to satisfy
the earlier inquirers until being subjected to a degree of scrutiny by the
Secret Service that Dr. Imanishi-Kari could not have expected. ORI Reply Br.
5. The fact that the other scientists who looked at the data accepted them as
looking "real" and as adequately supportive of the reported results, despite
the evident imperfections, could also be interpreted as meaning that the data
are real and that this unprecedented level of scrutiny might uncover similar
inexplicable oddities in any real data.
24.
For example, Table 3 contains the notation "NP" after several hybridomas,
which had no meaning in the context of this table and was apparently carried
over accidentally from other work. Table 2 contains an evident numerical
error showing a total of 1/144 normal spleen hybridomas as 17.2.25 idiotype
positive and then a total of 3 hybridomas are counted under subcategories of
idiotype positives with a footnote indicating that one of these was not
17.2.25 idiotype. Figure 3, which presents molecular data and was not
challenged in this case, refers in the legend to a Part C which does not
appear in the figure. Figure 4, which also presents molecular data and is not
at issue, shows the hybridization probe constructed from a 236 bp restriction
fragment whereas the legend to the figure cites a 233 bp fragment.
25. Dr. O'Toole appeared to subscribe to this conspiracy theory, at least
as to the period after her challenge, having stated that "at the meeting with
Dr. Eisen and co-authors Drs. Baltimore, Imanishi-Kari and Weaver, Dr.
Baltimore decided on the course of action for the authors (i.e., a cover-up)."
Ex. H265, at 3. She also accused Drs. Huber and Wortis of having "declared
their intention of orchestrating a cover-up." Ex. H284, at 4; see also Ex.
H263, at 2. She accused the NIH Scientific Panel of bias, accepting "totally
impossible explanations," "hypothesizing totally ridiculous and
unsubstantiated theories," and "performing contortions of logic and denying
the undeniable." Id. at 7-8.
26. For example, the people that Dr. O'Toole has accused of making false
statements in this matter include Drs. Baltimore, Eisen, Wortis, Huber,
Woodland and Imanishi-Kari. See, e.g., Exs. H265, at 4; H270, at 3; H272, at
2; H276, at 2-3; H290, at 6, 9.
27. Reacting to a suggestion that he could have evaluated Dr. O'Toole's
concerns by reviewing Dr. Imanishi-Kari's laboratory notebooks, Dr. Eisen
testified that the idea was ridiculous:
Ridiculous because it doesn't take into account what looking at
notebooks entails. It entails an investment of weeks and weeks and
weeks and weeks. I couldn't do that. I'm paid by the NIH to do
research. Not to investigate notebooks endlessly.
Tr. 2025. Having in fact undertaken a detailed review of the laboratory
notebooks, the Panel can confirm the time and difficulty involved.
28. Dr. Baltimore testified that today scientists "keep records with an
eye to their perhaps becoming public," whereas in the mid-1980's, most
scientists "kept notes largely for themselves as a way of providing the
information they needed when they came to writing a paper so they could
describe in detail what they had done" and "notes in that period of time were
more a personal crutch than a public document." Tr. 2070. In fact, he
testified that he had known "scientists who kept surprisingly skimpy notes on
surprisingly unofficial pieces of paper. Like paper towels." Id.
29. We do not imply that scientific misconduct investigators are obligated
to invest the time and resources to repeat all questioned experiments, nor
that such a procedure would resolve all questions. Nevertheless, it is
interesting that even the Secret Service records do not preserve results in a
form allowing retrospective re-interpretation by others without reproducing
the experiment.
30.
Mr. Stewart pointed out that no findings were made about numerous alterations
in the I-1 notebook which appeared to be natural changes, as opposed to "a
change with some kind of intent." Tr. 4070. He testified that if he were to
try to make such a determination about the alterations in the work sheets, he
"would probably want to run ESDAs" (a test to detect impressions from writing
done above the page as discussed later); he would "probably want to do ink
analysis"; he might "try to see if this was from a pad;" in short, he would do
the "same type of things I did in this case." Id. The trouble with this
reasoning is that all of these tests would address the timing of the
alteration and the source of the materials (ink and paper) used to make the
alteration, but without knowing the substantive significance of the change and
the possible motivation for making such a change, the tests would say nothing
about intent. It is not self-evident that a change made at a later time or
using a different pen is less likely to be an honest or accurate correction
than one made immediately or in the same ink.
31. Mr. Stewart testified that this case was "a new experience" as far as
the "time lapse," and that "it would have been nicer in hindsight if we had
kept better work sheet records, but we didn't have any anticipation that it
was going to take this long to culminate this case." Tr. 4055-56.
32.
Reviewing an ink analysis which did not include a test of the contribution of
the paper from which one of the ink samples was taken, Mr. Stewart testified
that that indicated to him that he had already tested the contribution of that
paper on another plate. The following exchange ensued:
Q Oh, really. Where does it indicate that?
A It's my own knowledge. It makes no sense why I would have a plate
with just two paper blanks when I have three different tapes there
unless I had previously run them at some point.
Tr. 4087, discussing Ex. H532; see also Tr. 4067 (Stewart) ("guess" about
meaning of note). Similarly, Mr. Stewart testified that a lane on an ink
analysis plate that appears empty may have had a paper blank sample, that he
"can usually tell after the fact, but I wouldn't expect that you could be able
to tell." Tr. 4076. Asked if one should be able to reconstruct the findings
from the work sheet, Mr. Stewart testified that: "In a perfect world that
would be nice. If we could go back to the work sheet and know exactly what
occurred for that analysis. It doesn't always happen that way." Tr. 4046-47.
In evaluating the possible contribution of certain pages, Mr. Stewart elected
to test a sample of the paper only from one page because he reasoned that the
other pages "appeared to be a continual run" so that he "had confidence" that
the one page could represent the group. Tr. 4088-89, 4091; Exs. H529 and
H551.
33.
Both Dr. Mosimann and Dr. Speed have extensive experience in applying
statistics to the field of biology. Exs. H81; R37. ORI argued that we should
give more weight to Dr. Mosimann's opinions than to Dr. Speed's because Dr.
Mosimann has a scientific degree and has published articles regarding
statistical analysis of "fusion experiments." Dr. Mosimann's scientific
degree, however, is a bachelor's degree in zoology, and ORI did not show that
his studies included work related to radioimmunoassays. Both of the "fusion
experiment" articles Dr. Mosimann co-authored relate to essentially the same
analysis: determination of the expected average number of cells distributed
to each of the wells after a cell fusion, based on the number of wells
exhibiting growth. Exs. H794A; H794B. Neither article related to the testing
of supernatants from cells of a fusion to determine the properties of
antibodies produced by the cells.
34. Mr. Hargett testified that: "This whole case was unusual. This is
the first time, that I've ever known of, that we had a request from Congress.
It was a whole different thing for us. And -- would things have been worked
better if -- you know, yes it could have been done better, no question about
it." Tr. 3559-60. He further testified that this case was "not typical," in
that most of their cases are "not as complex as this, and certainly not as
large as this as far as documents are concerned." Id. While Mr. Stewart
recalled that the Secret Service had been asked to assist in investigations by
Congressional committees in the past on a few occasions, he noted that none of
those investigations anywhere approximated the size of this one. Tr. 3983-84.
35.
Mr. Stewart, who has worked with the Secret Service as a document examiner
since 1982, reported that the range of forensic investigations in which he
worked included "murder investigations to Nazi war criminal investigations to
nuclear armament transfers from one country to another; disputed documents of
all types, counterfeit currency, threats to the President, many different
types of cases." Tr. 3593.
36.
Thus, Mr. Hargett stated that his conclusions were as to "authenticity as to
the respective times," but that "[a]s far as falsification and fabrication,
that is not . . . my terminology." Tr. 3496. He further clarified that his
conclusions were that, based on all their tests, "some of these pages have
been manufactured" but that "[i]f you want to call that fabrication, I don't
know. I just don't know." Tr. 3498. Asked if what he meant by
"manufactured" would include a situation where someone would "take a page and
sit down with a bunch of data that had been collected over a period of time
and select pieces of that data . . . and somehow put it together, after the
data had been created originally," Mr. Hargett agreed that that "could be a
manufactured page, yes." Tr. 3498.
37.
As a result, many of the inferences which they drew from their findings were
not adequately supported. For example, because we find that the material now
in the I-1 notebook was collected and organized at many different times and
did not purport to have been put in the present format or order at the time
the experiments were done, we could not infer fabrication from evidence
regarding the order in which pages were created or regarding the dating of
experiments. We discuss below the evidence relating to individual pages. The
general limitations of the forensic analyses of the I-1 notebook that we have
discussed here, however, inform our assessments of the implications of various
anomalies in production of or alterations to notations on those pages. It
must be noted that we are not able to rule out in every case the possibility
that some changes were made by Dr. Imanishi-Kari in 1988 or made with an
awareness of the issues under investigation. The limitations of the forensic
documentation examination simply do not permit us to distinguish changes made
in the course of organizing the data over the months from changes made much
later.
38. Dr. Imanishi-Kari explained this in a 1990 interview at NIH as
follows: "My books were not books. My books were -- that one spiral notebook
and something [data] inside of here [manila folders] books." Ex. H103, at 47-
48 (brackets to transcript citations indicate handwritten changes by Dr.
Imanishi-Kari). She also stated that these materials were not stored in any
one location but "went all over the place, these data" and that "[w]e took all
over. We took to the lab. We took to Moema's lab. We went to the counter.
It shifted. It went sometimes -- [with Weaver]." Id. at 48. "So, they were
kept in different folders in different things and they were kept all over the
place." Id. at 50.
39.
It appears that sometimes she forgot to record the necessary information too,
since she testified that if she had not labelled a counter tape, she would
throw it away because she would not later know what experiment it was. Tr.
5256. Such mishaps resulting from careless practices may account for some of
the missing or problematic data.
40. The counter tapes are generated from continuous paper rolls of about
10 inches in width. The actual number readings are printed in a narrow column
(single or double spaced, depending on the counter) running down the tape. At
intervals the tape may be divided into a "page" by spacing and a broken line
and (depending on the counter) a register number (discussed further below in
relation to the findings about register numbers).
41.
Dr. Imanishi-Kari did all of these at different times, and all of these
practices are reflected in the notebooks of other researchers in the record.
42.
Her cavalier attitude toward dates contributed to the enormous difficulty in
sorting this matter out over the years, but is not unique among scientists at
the time even in this lab. Our review of the Maplethorpe and Weaver notebooks
showed considerable unreliability in dating. For example, Dr. Maplethorpe's
notebooks have some consecutive pages dated with different years but the same
month. Dr. Weaver has written that he was "not in the habit of dating every
page," so that "a significant number of the data sheets and autoradiographs
were not dated." Ex. H254, at 2. Consequently, he submitted his data with
approximate dates (such as "about May 1985") and stated that "undated data
should be regarded as having been recorded" in the period from March 1984 to
July 1985. Id.
43. The present numbering of the pages in the I-1 notebook was not put on
by Dr. Imanishi-Kari but was apparently added by investigators at some point
in the process, possibly at the Subcommittee. Tr. 3471-74 (Hargett), 5149
(Imanishi-Kari).
44. ORI also claimed that Dr. Imanishi-Kari's brief was inconsistent in
describing how she organized data because it stated that she might organize
tapes from very different dates on a page to compare data but also stated that
she might not have had any reason to organize the counter tapes immediately
where no comparison was involved. ORI Reply Br. 4, citing R. Br. 4-5. These
statements in Dr. Imanishi-Kari's brief are not inconsistent--she might
organize counter tapes from an earlier experiment when she got results on a
later one that required comparison or she might simply get around to
organizing an old experiment when it was needed for a paper or some other
reason. It is plain from a review of the notebooks that data from different
assays were in fact compiled onto the same pages and that these assays were of
a magnitude unlikely to have been performed simultaneously. Dr. Imanishi-
Kari's statements more likely mean simply that whenever an assay was performed
that was to be compared with other earlier work, there was reason to organize
the tapes together because she could not fully evaluate the second set without
putting them side by side.
45. Thereafter, the Secret Service obtained additional notebooks,
including a box of additional materials from Dr. Maplethorpe in late 1990, for
an eventual total of about 62 notebooks of one kind or another according to
the examiners. Tr. 3501, 3515 (Hargett). The present record includes more
than 70 "notebooks."
46. As noted above dating irregularities were not unique to
Dr. Imanishi-Kari. ORI did not establish through testimony that the
researchers who produced the notebooks used as comparisons viewed accuracy in
dating as more critical than Dr. Imanishi-Kari did or that they habitually
compiled their data into notebook form (for those whose materials could even
now properly be considered to be in a "notebook" form) when they did the
experiments.
47. Of course, proceeding in this way risked a self-fulfilling prophecy.
Removing from the definition of a "normal" notebook one that contains the
characteristics encountered in the questioned notebook defines those
characteristics as abnormal. We do not share Dr. Imanishi-Kari's view that it
was inappropriate for the Secret Service to abandon the R-1 notebook as a
comparative norm, since the Secret Service could perhaps reasonably decide not
to treat any of the questioned notebooks initially presented to them for
evaluation as a legitimate source of standards. Cf. R. Br. 19. However, it
is somewhat more troubling that the Secret Service then proceeded to treat the
I-3 notebook as a comparative norm when its provenance was the same, because
the only distinction made between them was that the R-1 notebook did have many
of the aberrations noted in I-1 and the I-3 notebook did not. Tr. 3613-15,
3860-61 (Stewart), 3231-33 (Hargett). Also, Mr. Stewart testified that his
choice of norm would not be affected by the scientific content or organization
of the notebook because it would not affect the "forensic evidence," but there
was evidence that the I-3 notebook might differ from I-1 precisely because it
contained mouse screening records for which chronology was much more
important, which could affect the way it was compiled and organized. See Tr.
3860-62 (Stewart).
48. As we noted, the Secret Service raw data records contain alterations
and erasures as well, so in themselves such flaws are not significant. Mr.
Hargett testified that when anomalies were found in other notebooks, the
examiners would assume them "to be innocent changes, perhaps or normal
changes, as were some of the changes in the I-1 notebook," unless some special
significance were found. Tr. 3553-55. However, it does not appear that the
other notebooks were scrutinized as was I-1 to seek matching inks or take
impressions of each page to see what writing had been on top of it. Tr. 3552
(Hargett) (impression analysis done of only six notebooks, including I-1).
The Secret Service criteria for distinguishing "honest date changes" from
meaningful alterations was whether the examiners got results on other tests,
i.e., whether "they were multi-faceted type things." Tr. 3546 (Hargett).
However, while it may be more reasonable to conclude, for example, that a
change was made at a different time than other writing on a page when only
part of the writing shows up on an impression analysis or if you also know
that the ink used on that portion of the writing is different from the ink
used on the rest of the page, it is not necessarily more reasonable to
conclude from those facts that it is more likely that the change was made for
a dishonest reason. Evaluating whether a change or deviation in sequence
could result from innocent reasons is heavily related to the content of the
change and the existence of some potential motive or other indicia of intent.
It is difficult to see how the Secret Service ruled out any special
significance to the anomalies in other notebooks without knowing anything
about the substance of the work in them or the nature of any publications or
grants relying on them. It is true that a change of date by a day or two is
more easily recognized on its face as a possible immediate correction of an
error than a change from October of one year to January of the next (as is
alleged in relation to certain pages in I-1), but whether the latter type of
change is logically explained depends on the researcher's practices. Cf. Tr.
3662-71 (Stewart). In this case, compiling data after-the-fact and relying on
protocols to match up experimental results with probable dates could
potentially lead to "innocent" dating errors of more than a day or two.
49. As discussed in detail below, this question of whether the universe of
notebooks was obtained is particularly important in relation to whether
counter tapes in the I-1 notebook matched those being produced by other
researchers around the same time.
50. Direct requests were also made to Dr. Maplethorpe and Dr. O'Toole for
notebooks. Tr. 3515, 3551 (Hargett), Tr. 6127 (O'Toole). It is somewhat
troubling that such requests were directed to the person who challenged the
paper and to a researcher whose hostility to Dr. Imanishi-Kari was
longstanding and well-known (especially since green tapes from his notebooks
formed much of the basis for finding that Dr. Imanishi-Kari's green tapes were
from much earlier dates). Cf. Tr. 5760 (Maplethorpe), 6147 (Igras) (heard Dr.
Maplethorpe say about Dr. Imanishi-Kari that he would "get her somehow"). In
addition, although much emphasis was placed on the absence of green tapes in
Dr. Maplethorpe's notebooks after January 1984 (since his green tapes were the
most recently dated in the record except for Dr. Imanishi-Kari's), we have no
assurance that Dr. Maplethorpe turned over all of the green tapes which he
generated during the relevant period.
51. It is somewhat ironic that such efforts were made, when the
objectivity of the examiners was under a more direct threat from the contacts
made by certain Subcommittee staff. Mr. Hargett testified that Walter
Stewart, for example, in interacting with the Secret Service, was a strong
advocate of the view that misconduct had occurred. Tr. 3505-08, 3547-48,
3570-71. Although the examiners testified they did not consider such
representations in deciding how to proceed, resource limitations made them
gladly accept the guidance of the Subcommittee to focus on the I-1 notebook
and to rely on the Subcommittee's efforts to obtain the comparison notebooks,
which they accepted as unquestioned. Tr. 3874-77 (Stewart).
52. We deal with the specific green tapes at issue in relation to
particular charges in later sections. Here, we discuss the evidence about
green tapes generally and the weight properly given to evidence about
"matches" of tapes.
53. ORI complained that Dr. Imanishi-Kari was arguing that "valid forensic
conclusions about the green tapes" are "impossible absent perfect
information." ORI Reply Br. 13. Nothing prevents valid forensic conclusions
from being reached based on testing the green tapes in existence or requires
that unattainable perfection be achieved. Logic demands, however, that
conclusions based on the present absence of comparable tapes from a specific
time period rest on reasonably certain information about what other tapes were
generated at that time. The undisputed testimony that the counter machines
were almost constantly in operation and that they generated a steady rate of
tapes indicates that we may have no more than a small fraction of the tapes.
54. Unfortunately, no inventory of the notebooks and their contents
appears to have been made, nor any log book kept to record access to them
during the period (which may have been a number of years in some cases) when
they were not in the possession of the Secret Service. Tr. 3509-12 (Hargett);
see also Affidavit of Barbara R. Williams, Ph.D., August 11, 1995. This
omission raises the small but disturbing possibility that additional green
tapes were present but were lost or removed.
55. Dr. Imanishi-Kari pointed out that green tapes appear to have been a
small share of the total tapes produced. R. Br. 26. For example, only five
of the researchers' notebooks examined had any green tape in the period from
1981-85. Ex. H503, at 3. ORI responded that numerous green tapes appear in
some of the older (1981-82) notebooks, e.g., over 100 green tapes in the
Pasternak notebooks. ORI Reply Br. 13. However, the relevant point is that,
assuming that the proportion of green tapes available in the later period
(1983-1985) was small compared to yellow tapes, it would be particularly
important to have a larger share of the total tape production to try to
pinpoint exactly when the green tapes finally ceased to be used.
56. Furthermore, it was not disputed that the paper used in the counter
machines was likely to be available from many sources. Apparently, the
companies that marketed the counter machines resold tape rolls since Ms. Igras
testified that she purchased the tape for MIT only from Packard. See Tr.
3738-39 (Stewart); Tr. 4575 (Igras). The investigation did not rule out MIT
obtaining green counter tape at a later date than it would have last been seen
at Western Union (even assuming the Western Union employee's general memory of
a 1983-1984 phase-out was intended to be exact).
57. An expert witness for Dr. Imanishi-Kari (Mr. Richards) also presented
a theory concerning the green tapes. He stated that he received information
that each counter came with a small amount of beige counter tape, and
contended that, because of lack of any other evidence to the contrary, the
beige tapes under certain conditions of light and heat would eventually turn
green. He also noted that the color of counter tape paper under cellophane
tape was different (and greener) than uncovered tape paper, and suggested that
a further "shift to green" might result from solvents in the cellophane tape.
Tr. 4259-63, 4372-74, 4381, 6254-55. Although the Secret Service examiners
experimented with heat and ultraviolet light and were not able to alter the
tint of yellow counter tape to get a green shade (although aging and browning
did occur), Mr. Richards argued that the possibility of sunlight or chemicals
causing such a color change in beige paper was not ruled out. Tr. 4262-64,
6184-85, 6221-22, 6232-33 (Richards), 3621-22, 3626, 5537 (Stewart). Mr.
Stewart testified that the cellophane tape probably could also cause paper to
retain color while uncovered paper faded, but stated his opinion that the
greenish tint was not the result of covering with cellophane tape. Tr. 5538.
ORI questioned whether any beige paper was in fact provided, and if so,
whether it was likely to still be in use so many years after the purchase of
any new counters. See ORI FFCL IV.H.v.9. In any case, whether the green
tapes were a color variant of yellow or an effect of cellophane taping or a
color change of a beige shade, we are confronted with interpreting the pattern
of these green tapes appearing in decreasing frequency from 1981-1985.
58. ORI theorized that green tapes petered out in June 1983 with a few
later instances in December 1983 and January 1984 found in Dr. White-Scarf's
and Dr. Maplethorpe's notebooks. ORI Reply Br. 13. This theory posits an
innocent gap of more than six months between appearances of green tape in the
record. If green tape were phased out as stocks were consumed, it is
reasonable that green tapes would become less common and more sporadic in the
notebooks. It is possible green tape was used in 1984 and 1985 only in the
form of old partial rolls used when tape ran out or on a printer used
occasionally as a back-up or substitute. See, e.g., Tr. 5105 (Imanishi-Kari).
ORI acknowledged that the January 1984 green tape in Dr. Maplethorpe's
notebook was something of an "outlier" with no surrounding examples. The
absence of "surrounding" green tapes makes clear that the absence of a
continuous run of tapes of the same color sufficient to account for a complete
tape roll is not an occurrence unique to Dr. Imanishi-Kari's notebooks.
59. This ambiguity highlights the unresolved question of whether other
researchers' dating and organizing practices were any more reliable than
Dr. Imanishi-Kari's. We have no testimony or affidavits from most of the
other researchers whose notebooks were reviewed about what the dates in their
books meant in relation to when the counter tapes were generated and whether
they were organized chronologically so that undated material could be
approximated based on neighboring pages.
60. The examiners determined that the printers were not manufactured by
the companies providing the counters. Tr. 5541-42, 5579-88 (Stewart), 5936-37
(Dahlgren), 6164 (Fitzgerald). It is likely the teletype printers sold with
the Beckman gamma counters were originally manufactured by Teletype
Corporation and may have been obtained through the Western Union Telegraph
company. See generally ORI FFCLs IV.E.1-11.
61. The information about the format of the Packard gamma counter and the
font of its associated printer was presented incorrectly in ORI's FFCLs but
correctly in ORI's brief and in the sources cited in the FFCLs, so we conclude
that it is not in dispute. Cf. ORI Br. 69; ORI FFCL IV.D.21.
62. Mr. Stewart was aware of the danger that he might "have multiple
printers that are appearing as one to me." Tr. 3737. While he sought to
address that in his interviews with printer manufacturers, nothing in the
record indicates that the examiners obtained information sufficient to rule
out the possibility of multiple printers.
63. Ms. Igras testified that in 1982 a lot of new equipment was purchased
to equip the Whitehead Institute when Dr. Baltimore moved his laboratory there
and that "those pieces of equipment that were left behind, Ward Deharo put
them in the basement of the Cancer Center." Tr. 4588. The old equipment
"included a Teletype." Tr. 4574 (Igras).
64. "I certainly know that they [the counters] had printers with them
built in or beside them and that when they broke . . . I went and found
another and switched them." Tr. 4448 (DeHaro). Such a change using either an
excess printer from the basement or alternating a working printer between two
Beckman counters was a matter of a "couple of minutes, three, four, two
minutes. You just picked -- unplugged the -- one, the data line, the power
line, move out of the way, move another one into it, into place. . . . They
weren't light, but you could do it, and just plug it on the back, plug the
power in and away you went, if it worked well." Tr. 4455 (DeHaro).
65. ORI made this claim in the context of claiming "full matches" of I-1
green tapes to certain earlier Maplethorpe tapes even though the format makes
clear that they came from different counters made by different manufacturers.
These matches would not have any meaning unless the Maplethorpe tapes were
produced on the same printer as Dr. Imanishi-Kari's tapes. Mr. DeHaro and Ms.
Igras testified to their belief at the time (well-founded or not) that they
could not switch printers between Beckman and Packard counters. Tr. 4455
(DeHaro), 4572 (Igras).
66. In light of how little certainty existed about the availability and
use of specific printers and counters much closer in time and space to the
relevant period (i.e., by MIT in 1989), it is not surprising that we are
unable to reach conclusions with any more certainty almost seven years later.
67. The document examiners employed thin-layer chromatography (TLC) to
analyze ink by separating and examining dye components. Tr. 3763-64
(Stewart).
68. In fact, matching ink clearly must have come from entirely different
ribbons in some instances. The examiners claimed a match between certain
Dr. Imanishi-Kari green tapes and a whole set of Maplethorpe tapes from a 21-
month period (April 20, 1982-January 15, 1984), and these tapes could not
possibly all be from a single ribbon.
69. A further complication was that Mr. Stewart's testing may not have
ruled out the possibility that test results might vary on one ribbon if the
ink formula changed or fluctuated in producing the ribbon. Cf. Tr. 3759-61
(Stewart). ORI considered this implausible, since ribbons were produced in
large batches and since Mr. Stewart (being unquestionably expert in ink
analysis) did not mention it. ORI Reply Br. 18. However, Mr. Stewart was not
asked one way or the other about the production of typewriter ribbons and the
application of ink (unlike the production of writing pads, about which
considerable evidence was adduced), so we can draw no conclusion about whether
ink formula would be expected to be uniform across a ribbon. ORI also pointed
out that the Secret Service took samples from a number of different points
along the tested counter tapes, so that arguably any variation in ink
formulation would have been discovered. ORI Reply Br. 18. This argument is
flawed, however, because (1) the Secret Service took samples of ink only from
relatively small segments of counter tape, not along the length of the ribbon
itself, so the samples are likely to represent only a small area on the
printer ribbon (a single ribbon lasted about 90 days), (2) samples of ink from
counter tape segments were apparently pooled for testing, so variation within
the ink on a segment might not be noted, and (3) there is no evidence that any
tests for this purpose were ever conducted.
70. The ink on a tape dated March 29, 1982 generated by another researcher
on the same counter was different from that on Maplethorpe tapes with the
surrounding dates including March 23 and 30 and April 16th. Ex. H532 (compare
Reilly and Maplethorpe tape results). The Secret Service suggested that this
might have resulted from a change of ribbon and from misdating by the second
researcher so that the change actually occurred after the last Maplethorpe
tape (or two changes were made within three weeks). Tr. 4092-95 (Stewart).
Similarly, the White-Scharf tape dated December 1, 1983 did not have ink
matching those of tapes near in time, but the Secret Service suggested that a
substitute printer might have been used. Ex. H503, at 3. As Dr. Imanishi-
Kari argued, the same kind of eventualities could account for differences in
her tapes. R. Br. 33-34, n.41.
71. We have pointed out elsewhere that the dates on pages with counter
tapes in the I-1 notebook do not necessarily purport to be the dates of the
experiments themselves and that the dates in comparison notebooks have not
been shown to be any more precisely related to the dates on which tapes in
those books were generated.
72. Even the inference that pages with different defects did not come from
a single pad is not certain since Mr. Stewart testified that it was possible
the defects which he used to distinguish two different sources could have
occurred on pages which were interleaved into the same or multiple pads
alternatingly and that different thicknesses of paper did not necessarily
imply different pads. Tr. 3967-69, 3972-73.
73. Actually, the Secret Service expressly found that both inks used on
the June subcloning pages, for example, were available on the "purported
dates" of those pages. Ex. H503, at 1.
74. Dr. Imanishi-Kari pointed out in her brief at least one instance
occurred in which stacking is the only possible explanation for material on
one page appearing in registration on another, because the pages are from
different sources. R. Br. 79, n.103; I-1:86-87; Ex. H539. Furthermore, Mr.
Hargett acknowledged that such small portions of the writing of several
critical pages appeared in registration that stacking might explain those
pages as well. Tr. 3453-54 (I-1:121 and I-1:5), 3464-67 (I-119 and I-1:7-9;
I-1:107 and I-1:31).
75. In some instances, ESDAs (not necessarily in registration) were also
used as evidence that portions of some pages were written at a different time
than some other material appearing on the same page. This inference was drawn
when only one portion of the writing on a page appeared on an ESDA of a page
which must have been underneath at the time when that part was written (since
it received an impression). However, the examiners acknowledged that the
difference in time could be a matter of minutes if the pages happened to be
moved in relation to each other. Tr. 3529 (Hargett), 4014-15 (Stewart). In
fact, even if they were not moved, an ESDA does not necessarily pick up the
impression of every piece of writing placed on a page while in position above
another. Some impressions simply do not happen to come through or at least
are not successfully captured by the ESDA process. The idea that such ESDA
results imply that some writing was added years later in an attempt to deceive
is hence not well-founded.
76. We discuss Dr. O'Toole's allegations that these pages were brand new,
and that Dr. Imanishi-Kari said at the meeting that she had just produced
them, in relation to the charges concerning Figure 1, and conclude that Dr.
O'Toole's interpretation of what Dr. Imanishi-Kari said about these pages was
improbable and uncorroborated. Cf. Tr. 984-87 (O'Toole). Had
Dr. Imanishi-Kari just finished fabricating these pages with an intent to
deceive, she would hardly be likely to announce that fact or express
resentment at the trouble involved.
77. "Ig" is shorthand for immunoglobulin. IgM antibodies are those with
the æ isotype, but are produced in two allotypic variants, æa and æb.
78. Dr. Imanishi-Kari stated in an interview with NIH that the vials with
iodinated material were dated and unusable material disposed of. Ex. H103, at
125-28.
79. In a 1990 interview with NIH, Dr. Imanishi-Kari stated that she had
problems with BET-1, not in terms of specificity, but in iodination, depending
on protein concentration. She stated that "in the beginning when I purified
BET-1, I couldn't get a lot of Bet-1 purified from the supernatants and the
protein concentration at that time was not very good," and that iodination was
problematic with the low concentration of protein with which she was working
at times. Ex. H102, at 144, 146-47.
80.
ORI made no charges of scientific misconduct in relation to the loss of the
raw data on the fourth dilution data points, admitting that it had
"insufficient evidence to hold Dr. Imanishi-Kari directly and specifically
responsible," while still asserting that the fourth data points must be
fabricated. ORI Report 61. It is hard to see why ORI accepted that
Dr. Imanishi-Kari could have relied on Dr. Reis in regard to these data but
that Dr. Imanishi-Kari should nevertheless be held directly and specifically
responsible for the other shortcomings charged in relation to Dr. Reis's work
in Figure 1.
81.
There was unrebutted expert testimony that doing this was not scientifically
difficult using the equipment then available at MIT. Tr. 1914-15 (Eisen); R.
Br. 44.
82.
For purposes of this section, we consider all the data in the experimental
record before us as authentic to determine if failing to report the discrepant
results with BET-1 constituted deliberate misrepresentation. The following
section addresses ORI's allegations that some of the experiments in which BET-
1 performed well were fabricated. Since we conclude there that ORI did not
prove that those pages were fabricated, we need not consider here how our
conclusions would be affected if portions of the experimental data were
disregarded as fabricated. One difficulty with the assessment by ORI's
scientific experts about whether the representations about BET-1 were
misleading is that they discounted those pages which were forensically
challenged, assuming their invalidity as data. ORI considered Dr. Eisen's
evaluation of the experimental evidence to be "limited, at best" because he
did not review the statistical and other forensic evidence. ORI Br. 39.
Since we do not share ORI's assumption that the questioned pages were not
legitimate data, we find more useful for our purposes here (in evaluating
whether the reporting regarding BET-1 in the Cell paper was deliberately
misleading) the testimony of scientists who considered the entire experimental
record.
83. The authors published the required correction in Cell in 1989. Ex. H3
(57 Cell 515). The correction stated that iodinated BET-1 was sometimes not
specific but that data from those occasions were not used in the paper. The
correction further stated that, when working, BET-1 "could discriminate with
1,000- to 10,000-fold specificity" in favor of æa. Id. In addition, the
correction published further data on BET-1 specificity drawn from I-1:121.
ORI challenged the correction too as deliberately misleading because:
(1) Dr. Imanishi-Kari knew that iodination was not the cause of nonspecific
binding as the correction implied; (2) BET-1 did not generally discriminate
with the level of specificity claimed in the correction; and (3) I-1:121 was
fabricated. See ORI FFCLs XIII.1-14. We discuss the charges relating to I-
1:121 in the next section. The degree of specificity is discussed in the text
and is not out-of-line with the assessments of the NIH Scientific Panel and
witnesses before us. The possibility that iodination might affect specificity
was described in the NIH Scientific Panel Report as "reasonable," though
unproven. The correction does not claim that the authors knew that iodination
problems caused the non-specific binding, and ORI did not prove that
Dr. Imanishi-Kari knew of another cause for the inconsistent performance of
BET-1. Dr. Dahlberg asserted that damage to an antibody during iodination
would affect its ability to bind at all rather than its ability to
discriminate, but ORI did not prove that effects on specificity could not
occur. ORI pointed to I-1:110 as evidence that BET-1 still showed high cross-
reactivity, even when not iodinated. ORI Report 68, 89, n.53. But we found
that the degree of cross-reactivity shown at I-1:110 properly considered is
much lower, so that page supports the opposite conclusion. Scientists
testified that the denaturing caused by iodination could cause non-specific
binding. Tr. 1921-26 (Eisen), 1293 (Davie). The important point is that,
whatever the source of the occasional problems with BET-1, Dr. Imanishi-Kari
and Dr. Reis, and others using it, obtained good specificity results on other
occasions, were able to tell when it was working well, and relied on those
data.
84. These results conflict with Dr. O'Toole's assertion that BET-1 "never,
ever, ever, ever worked" for her as a æa specific reagent in an RIA. Tr.
1064; Ex. H109 at 23. Instead, they support Dr. Imanishi-Kari's testimony
that Dr. O'Toole's data showed BET-1 specificity on her assays, too. Tr.
4954-55. ORI apparently did not credit Dr. O'Toole's position that BET-1
lacked all specificity, stating that "neither Dr. Dahlberg nor any of ORI's
other experts ever contended that BET-1 could not discriminate between æa and
æb." ORI Br. 39. Rather, ORI limited its position in its brief to the claim
that BET-1 did not discriminate elsewhere as well as depicted in Figure 1.
85. ORI also pointed to the fact that the correction letter refers to
BET-1 as a "key reagent" as further evidence that its specificity was
important to the Cell paper. ORI Br. 35; Ex. H3. The fact that BET-1 was
undoubtedly important in identifying the transgene does not mean that its
allotype specificity being relative rather than absolute, and therefore
potentially exaggerating the presence of transgene, undermines its role in the
paper.
86. However, Dr. Davie, who testified for ORI, stated that he did not find
it surprising that the values obtained with sera exceeded the highest value
with the positive control protein, since it was comparing "apples and
oranges." Tr. 1300.
87. The corresponding percentages of cross-reaction for AF-6 in these
experiments was calculated by ORI as ranging from 3-14%, except for R-1:34
which was 41%.
88.
In fact, Dr. Dahlberg testified that four of the assays in his analysis in the
ORI Report at 65 are "consistent with" the specificity in Figure 1, if he were
not questioning their authenticity. Tr. 529.
89.
An example of the impact of the different approaches to assessing cross-
reactivity is Dr. Eisen's discussion of ORI's comparison of BET-1 data at I-
1:75-78, which were not published, to R-1:37-40. ORI plotted the average
values for BET-1 bound to transgenic and normal sera in each assay and
emphasized that the unpublished assay had a 30% average level of cross-
reactivity. ORI Report 62, Ex. C. Dr. Eisen testified, however, that the
unpublished assay showed a 100-fold discrimination in favor of æa, which is
"perfectly satisfactory specificity." Tr. 1918-19. Dr. Capra agreed that the
30% average cross-reactivity for the first dilution calculated by Dr. Dahlberg
in that graph is not an accurate demonstration of non-specificity and that
looking at all the dilutions shows that BET-1's reactivity to the transgenic
and normal sera differed substantially. Tr. 2822-23. He concluded that both
the published and unpublished data sets would support the same conclusion,
i.e., that BET-1 unambiguously and clearly discriminates by allotype.
90. Dr. Dahlberg correctly pointed out that in assays using an anti-
idiotype coat very few idiotype-positive antibodies of any kind would be
captured in normal mouse sera so that the BET-1 probe would have little target
to which to attach. Hence, it would be difficult in such assays to determine
if the BET-1 count on normal sera was low because the probe was specific for
only æa or because there were simply no idiotype-positive antibodies present.
The control proteins, by contrast, are known to be idiotype-positive with æ
heavy chains of the allotypes of the specific mouse strain targeted, so they
would be expected to attach to the anti-idiotype coat and provide a target for
the anti-allotype probes. On this basis, ORI disregarded some of the assays
to which Dr. Eisen pointed in his testimony as further examples of good
discrimination by BET-1. ORI Br. 39; ORI FFCL IX.F.ii.9-20. However, this
point did not account for all the overlooked assays.
91. ORI's position on this assay overlooked the fact that it was run on an
anti-kappa coat which would capture almost all antibodies in normal mouse sera
and therefore should provide ample targets to test BET-1's specificity even if
the controls were performed on sera rather than control proteins.
92. This testimony is corroborated by her similar use of the names of the
mouse strains on R-2:6, where she pointed out that the listing of
concentrations instead of dilutions was more consistent with purified proteins
than sera. Tr. 2658-59. Where Dr. Reis did use sera, the specific mice from
which the sera came are identified. R-2:47; R. Br. 42, n.52.
93. Their initial reaction of anger and dismay belies the claim that
Dr. O'Toole's memory of early events in this dispute differs from that of
virtually every other participant because Dr. Imanishi-Kari's friends
immediately closed ranks to protect her regardless of culpability. Dr.
O'Toole relied as evidence of this protectiveness on her allegation that Dr.
Wortis announced in her presence that he would have to "rehabilitate"
Dr. Imanishi-Kari if Dr. Imanishi-Kari could not "explain away" the problems
with the paper. Tr. 953-54 (O'Toole). Dr. Wortis denied that he ever said or
thought that Dr. Imanishi-Kari needed rehabilitation. Tr. 2811. Dr. O'Toole
apparently used the word "rehabilitate" as implying a whitewash of
Dr. Imanishi-Kari's reputation, but, in fact, the phrase seems as likely to
imply a need for some retraining or corrective action against Dr. Imanishi-
Kari had she not explained adequately. It is implausible that, were Dr.
Wortis to have intended to somehow protect Dr. Imanishi-Kari if he found some
wrongdoing (which we do not think he ever intended), he would begin by
announcing that intention to the person who raised the concerns.
94. Dr. O'Toole asserted that Dr. Imanishi-Kari told her when she arrived
in the laboratory that Dr. Reis was recloning BET-1 because it had been
contaminated so that it was not specific and did not work well. Tr. 887-88.
Dr. O'Toole claimed no direct knowledge of whether such contamination occurred
or why Dr. Reis was recloning. Dr. Reis testified that while some plates (not
cells) were contaminated, she had recloned BET-1 only to get more reagent.
Tr. 2508-10, 2605 (Reis), 4903-04 (Imanishi-Kari).
95. ORI disregarded Dr. Marrack's testimony because she did not review all
of I-1 and the ORI Report in reaching her conclusions about the
appropriateness of Figure 1. ORI Br. 36. The scope of her review is
irrelevant to her testimony about standards of scientists in reporting
problems with reagents.
96. We note that ORI also used this assay (with 34% cross-reactivity) as
proof of BET-1's lack of specificity in its first charge on Figure 1.
97. One problem in sorting out why BET-1 sometimes failed to discriminate
well is that, as mentioned above, no records exist to trace individual batches
of BET-1 to determine if certain preparations caused the difficulty. The fact
that recloning occurred at a given date does not imply that all experiments
after that date used BET-1 iodinated at the same time or that all conditions
in later assays were otherwise ideal.
98. The data on I-1:111-12 do not seem to have been needed for any other
purpose and so retaining them is particularly inconsistent with the idea that
Dr. Imanishi-Kari was intentionally doctoring the record to support BET-1's
specificity. I-1:113 was among the pages shown to Dr. O'Toole early on as an
example of endogenous idiotype-positive clones, since it included an assay on
anti-idiotype coat with an AF6 probe. The controls show that the separate
BET-1 assay was not working well, but the AF6 results were not affected.
Dr. Imanishi-Kari might have had reason to retain the AF6 results, but, if she
were intentionally tampering with the record, she could have removed the BET-1
results or moved the AF6 to a different page.
99. As discussed above, however, we do not share ORI's belief that
Dr. Imanishi-Kari "knew" that iodination was not the cause of BET-1's
unreliable specificity results. All that is established on this record is
that she knew BET-1 did not always work well and that she thought it
sufficient to disregard the results of assays where BET-1 did not demonstrate
100. The conclusion depends on the assumption that both tapes were
generated by the identical gamma counter, and the evidence on possible
"matches" assumes that the comparison tapes were also generated by the same
machine. The testimony indicated that they matched the format for a Beckman
7000 counter which was one of the two which Dr. Imanishi-Kari said she
generally used for experiments in the I-1 notebook. Tr. 648-49 (Mosimann).
However, while the format could be used to distinguish between the Packard and
the Beckman gamma counters used in Dr. Imanishi-Kari's laboratory, there were
gamma counters on other floors in the building, some of which may also have
been Beckman 7000s. Although Dr. Imanishi-Kari testified that she did not
believe she used those for any experiments at issue in I-1, she also said that
she might have. Tr. 5098. Dr. Mosimann testified that the comparison tapes
which he used to create a "time line" of the register numbers (to show that
the ones on these pages could not fit in during March 1985 and to support the
conclusion that the numbers increased at a slow and steady rate) were from the
same Beckman (at least one other Beckman was in the building at the time).
Tr. 653-669; Exs. H422, H438, and H278, at 6. While the progression was
persuasive, it is not certain that some of these tapes could not have come
from other Beckman 7000s. The MIT fact sheet on gamma counters stated that
they were located in common areas "available to all scientists in the
building" and that it was "not uncommon for researchers to move between floors
to use shared equipment as needed. Therefore, all the gamma counters in the
building could in theory be used by any individual at any one time." Ex.
H278, at 6-7. No records were kept that would connect any particular counter
tape to a specific gamma counter. Id.
101. Dr. Imanishi-Kari testified that the fact that these tapes were
pasted on as whole pages, and that the data in these sheets were not used in
the paper or for any speech or grant, suggested that she did not get around to
organizing them until relatively late, "probably . . . when I was organizing
the last piece of, pieces laying around." Tr. 5254. This scenario is
consistent with the forensic evidence, discussed below, that intervening pages
were organized quite late (perhaps in early 1986) and with the increased
likelihood of error in retrospectively dating them well after the experiments
were completed. Dr. Imanishi-Kari noted that she may have estimated the dates
based on the dates on the BET-1 purification protocol on I-1:110, which was
one of the spiral notebook pages, since she "may have just guessed" that these
BET-1 tests "may be related" to that series of experiments. Tr. 5256-57.
102. ORI admitted that it had no "forensic or other evidence specifically
indicting I-1:114," other than its association with the surrounding pages.
See ORI Br. 47. Thus, it is unnecessary for us to address that page, in light
of our overall conclusion that it is likely that the dates on all of these
pages are not reliable in relation to the dates of the assays, but that there
is no evidence of intentional deception.
103. In his testimony, Mr. Stewart repeatedly stated that I-1:113
purported to be from 1984. Apparently, he based this on grouping it with I-
1:30 and 41 which bear 1984 dates. Tr. 3703-09; see also, Tr. 3272-73, 3313
(Hargett). However, it is obvious that I-1:113 did not purport to be from
1984 since Dr. Imanishi-Kari has maintained consistently that the laboratory
did not have BET-1 until the end of 1984 or early 1985. In its brief, ORI
claimed that I-1:113 purported to be from March 1985. ORI Br. 43-46; see
also, Tr. 3711-12 (Stewart) (late 1984 or 1985).
104. It was not disputed that the I-3 notebook was from 1986 and was
compiled from the beginning as a mouse screening notebook, for which purpose
specific dates were much more important. Tr. 5151-55 (Imanishi-Kari).
105. Mr. Stewart indicated that they attempted to track "movement" of
certain defects in a pad to estimate if pages were taken from near each other
in same pad. He considered that the I-1 pages discussed here "clustered" with
I-3 pages. Tr. 3700-03. However, since the same defect can occur on pages
interleaved into many different pads, the precise location of the defect does
not necessarily correlate with the placement of the page within a particular
pad. Tr. 3967-69 (Stewart).
106. In addition, I-1:113 has writing in blue ballpoint pen ink that
matches the ink formula of the blue pen used on I-1:30 (also from the pages
grouped together by the Secret Service). Tr. 3706 (Stewart).
107. The assertion that they must all be from after February 26, 1986 was
not based on any unavailability of a particular type of pad or ink formula
before that date. Rather, the precise date was assigned simply because of the
link among the pages, and because no other instances of pad paper with the
precise matching defect was located in any other researchers' notebooks until
after February 1986. Tr. 3707-12 (Stewart). Of course, other researchers in
the building would not necessarily have shared a single pad or even pads from
a single package. In fact, the occurrence of matching pad paper in other
researchers' notebooks at any time reinforces the likelihood that paper defect
and thickness matches do not demonstrate a single pad source. Since we do not
have all the researchers' notebooks (and since pads may well have been
consumed for purposes other than preserving laboratory data), the absence of
matching pad paper before February 1986 is relatively meaningless and, in any
event, would not prove that the I-1 pages were compiled after May 1986, when
questions were first raised about BET-1.
108. ORI mocked the idea that the coincidences could have occurred
innocently, saying that it would require that a pad be used to generate
I-1:30, 41, 43, and 113, along with a black ballpoint pen and a blue ballpoint
pen; then all three items would have to be put away for two years; then all
three items would have to be pulled out and used to generate I-3:25, which
would have to be "stacked" with I-1:30 in the process of being generated."
ORI Br. 46. None of this is necessary. It would suffice for I-1:30, 41, 43,
(with late 1984 data) and 113 (with spring 1985 data) to have been organized
around the same time in 1985 using pens and pad paper which remained in the
laboratory for a few more months to be used in early 1986 to put data on
I-3:25. Other possibilities are that similar pads or pens from the same
batches were around, or that all of these data (none of it critical data which
needed to be in order before the paper was submitted) were compiled around the
same time in 1986 using counter tapes from when the experiments were
performed. Registration could have occurred either because the completed
pages remained on the pad and fresh pages were folded back over them or
because of stacking. See Tr. 3261 (Hargett).
109. The Secret Service report even concluded that I-1:41 was "produced
with the same pad of paper directly above" I-1:113. Ex. H500 at 2; Tr. 3266
(Hargett). As discussed above, however, this assumption is unwarranted, since
other methods could produce registration, and it is impossible to tell if the
page bearing the ESDA impression already had writing on it when the impression
was produced. Tr. 3261, 3565-66 (Hargett). Since no evidence established
that ESDA impressions could not be picked up by pages other than the one
directly underneath, the conclusion that writing was done "directly" above is
not supported by the ESDA. Mr. Hargett also considered the location of
defects in the pad paper in reaching this conclusion, but as discussed
earlier, this defect analysis did not suffice to identify paper as coming from
a single pad. Cf. Tr. 3540-42 (Hargett).
110. It would have been obvious that Dr. Imanishi-Kari was not claiming to
have actually done the experiments just before the meeting to satisfy Dr.
O'Toole, since these are assays that would require substantial periods of time
to undertake and complete.
111. The improbable and ominous construction which Dr. O'Toole put on
Dr. Imanishi-Kari's complaint is typical of the escalating pattern of
miscommunication running through the long history of this conflict.
112. Dr. Imanishi-Kari testified that she did not recall putting together
pages of data specifically for this meeting. Tr. 6477. However, that does
not mean that these pages purported to have been compiled in March 1985. She
has long maintained that she organized data from counter tapes on to pages as
much as several months later, so that these pages could have been produced in
late 1985 or early 1986 apart from the meeting. R. Br. 21-22; Ex. H120, at
146-48.
113. It is in recognition of this problem that ORI developed the bizarre
"Bad BET-Good BET story" to explain why Dr. Imanishi-Kari would fabricate
failure.
114. ORI did not claim that I-1:119 might have been compiled before August
1984 (which would have been highly unlikely since BET-1 was not in the
laboratory then). As to I-1:7-9, there was little conceivable reason to
misrepresent the dates on these pages, which contain unpublished preliminary
assays testing idiotype reagents. Of course, compiling pages in 1985
containing data collected in 1984 was not shown to be incompatible with
Dr. Imanishi-Kari's normal practices.
115. Another error in the Cell paper which the authors acknowledged in a
correction letter was a statement in the text related to Table 2 about the
non-æ antibodies: "The remaining 119 clones produced other Ig heavy chain
isotypes, the majority being þ2B (data not shown)." Cell paper 250 (emphasis
added). The correction indicated that the data on isotype were collected in
different experiments, not those relating to Table 2, and that it showed only
that most were þ, not necessarily þ2B. Ex. H2. The NIH Scientific Panel
considered the error in referring to isotyping done on a different set of
fusions and felt that it should be clarified, which was done in the
correction. Tr. 1335-36 (Davie). Although ORI proposed FFCLs asserting that
this isotyping claim is "fabricated," no such charge was contained in the
charge letter. See ORI FFCLs X.C.; Charge letter passim. For that reason, we
do not decide the issue. However, we note that substantial evidence in the
record suggests that the error resulted from miscommunication, apparently
confusing data on the most common isotype of Table 3 hybridomas and applying
those results to the number of non-æ hybridomas from the Table 2 fusion. Cf.
Tr. 2808 (Wortis). Dr. Weaver indicated that he may have added the sentence
without seeing the data based on his understanding of what Dr. Imanishi-Kari
told him. Tr. 2408-09.
116. As noted above, one of the obvious careless errors in the paper
occurs in Table 2. Although a total of only 1 idiotype-positive is reported
for the normals, the results for idiotype positive NIP-binders show one kappa
and two lambda positive, which would make a total of 3. A footnote indicates
that the kappa-NIP binder is not idiotype positive, which still leaves unclear
whether one or two normal hybridomas were idiotype positive.
117. The cut-off was not specified in Table 2 but was clarified in the
correction as being set at 1000, using negative controls which "showed fewer
than 600 cpm" so that a cut-off "at about 2-fold over background for safety"
was used. Ex. H3.
118. Without the counts for the negative results, no complete graph can be
made to determine the distribution. It should be observed, however, that 55%
of the results were omitted and presumably below the 1000 cpm cut-off. Cf.
Tr. 296 (Dahlberg).
119. More specifically, her testimony was that her general practice was to
use two to two and one-half times the background as her cut-off, but not lower
than 1000 cpm. Tr. 4869, 5490.
120. ORI asserted that the cut-off level was so egregiously unacceptable
that Dr. O'Toole "noticed it immediately and it was one of the aspects of the
17 pages that caused her the greatest concern." ORI Br. 55; Tr. 920-23.
However, her early memorandum to Dr. Eisen does not assert that the 1000 cpm
cut-off was inappropriate, but rather that the relative sensitivity of the
assays might differ and cause some transgene to be missed. See Ex. H231.
121. The NIH Scientific Panel noted this difficulty in its report, finding
that other assays of Dr. Imanishi-Kari's which it reviewed were consistent
with her representation that 1000 cpm was chosen to significantly exceed the
usual background values of 200-500, but that, without the negative or
background counts, this experiment could not be evaluated. Ex. H262 (NIH
Scientific Panel Report at 4).
122. Several witnesses also testified that 1000 cpm appeared to be a
reasonable choice of cut-off for this assay, apart from the specific relation
of the cut-off to the background. Tr. 3117 (Marrack), 2825-26 (Capra).
123. The fact that more than half of the counts in the normal and
transgenic assays were apparently below 1000 cpm (judging by the sample
numbers that were skipped because the negative results were not recorded) also
suggests that using a 1000 cpm cut-off did not result in all background counts
being recorded as false positives.
124. ORI says this demonstration that the 1000 cpm cut-off was used in
good faith and was effective is irrelevant because the normal portion of the
assay was ultimately discarded. ORI Reply Br. 27-28. However, this response
ignores the fact that the normal results were discarded precisely because the
cut-off showed so high a rate of positives that the researchers undertook
definitive molecular testing that established the mix-up. Cf. I-1:133.
125. We do not agree with ORI's assertion that Dr. Reis's testimony was
that she did not know to which experiment the controls related. ORI Reply Br.
28, citing Tr. 2650. Language difficulties caused some confusion at the
hearing but Dr. Reis stated clearly that she did not agree with the idea that
these controls were for the main fusion assay. Tr. 2530-32.
126. In addition, the ESDAs showed that a circle and arrow on the pages
which indicated that the controls went to the June 6th retest were added at a
different time than the June 6th retest data. Tr. 252-53 (Dahlberg); Ex.
H540; ORI Br. 58. This finding is not surprising since Dr. Imanishi-Kari
testified that she added the circle and arrow in the process of explaining to
Drs. Wortis, Woodland and Huber at the first meeting that these controls were
for the retest. Tr. 4858. At the least, this indicates that
Dr. Imanishi-Kari took the same position about these controls from the
beginning and not as a belated recollection long into the process.
127. The contrary results showing the presence of control data from R-1:34
on the ESDA of R-1:35 are visible to the naked eye despite the fact that Dr.
Dahlberg claimed not to have seen any control data information on the ESDA
after having "examined the rest of the original ESDA with a magnifying glass
and everything else that could be used to bring up faint images." Tr. 262.
128. This experiment is discussed in detail in a later section because the
normal data in Table 2 used to replace the normal mouse that was mistyped came
in part from these data.
129. The normal fusion was the other source of normal data for Table 2 in
lieu of the mistyped mouse. The transgenic fusions were not published.
130. In any case, there was no evidence presented that Dr. Imanishi-Kari
was directly involved in setting the cut-off for this particular experiment.
131. The first correction stated that the "data represent primary
hybridoma wells, not isolated clones." Ex. H2. The second correction stated
that Table 2 "summarizes a vast amount of serologic data on primary hybridoma
supernatants." Ex. H3.
132. The first correction stated that, while the number of clones per well
was not directly addressed in Table 2, it was possible to calculate from the
number of negative wells that "it was likely to be only one or a few." Ex.
H2. The second correction letter specified that the wells were "pauci-
clonal," with 20-40% with no growth. Ex. H3.
133. ORI pointed to no scientific evidence that any significant number of
normal hybridomas would be expected to produce idiotype-positive antibodies,
and our review of the data for many fusions in the record supports an
expectation of the very low frequency reported in Table 2.
134. Dr. O'Toole argued that it would have been possible for such a well
to contain a clone that was idiotype positive and transgene positive because
she believed that the anti-light chain reagent used to identify idiotype-
positive antibodies might be more sensitive than the BET-1 reagent, thus
picking up evidence of idiotype-positivity at a concentration of antibodies
insufficient for BET-1 to recognize the presence of the transgene. See,
e.g., Ex. H231, at 2. While this was an interesting scientific question which
was a focus of much discussion at earlier points in this matter (and an
example of the sort of challenge that the scientists first approached by Dr.
O'Toole considered a reasoned and serious scientific dialogue), it is
essentially irrelevant to any charge of fraud before us. No persuasive
evidence was presented that this theoretical difference in sensitivity existed
and, if it did, that Dr. Imanishi-Kari had any evidence of it at the relevant
time.
135. That this widespread ambiguity in terminology extended to Dr. O'Toole
casts doubt on her recollection that she was sensitive to this distinction
from the beginning. Certainly, she did not note any question about this on
the draft of the paper when she reviewed it, since no notation was made to
Table 2 or the discussion although the same terminology was used as in the
final paper. Ex. H227. At the hearing, Dr. O'Toole suggested that she was
sensitized to this point early in her time at the laboratory because
Dr. Imanishi-Kari told her to "represent the parent wells as clones in her
[Dr. O'Toole's] PC binder experiment, because if you don't say they're
clones, that's [the readers'] problem if they assume they're clones.'" ORI
Br. 61, quoting Tr. 874 (O'Toole). We do not find it credible that this
particular incident occurred as described. Certainly, Dr. Imanishi-Kari
clearly sought to press Dr. O'Toole to move forward with her experiments and
to publish. It is undisputed that Dr. Imanishi-Kari (who had herself been
under publication pressure) was concerned that Dr. O'Toole's career would
never progress if Dr. O'Toole, having been a post-doctoral fellow then for
eight years, did not produce successful publications. See, e.g., Tr. 872-73,
885 (O'Toole). Dr. O'Toole had previously been unable to obtain grants
because reviewers felt she needed to show more progress before funding. Tr.
858-62 (O'Toole). Dr. Wortis, who had been Dr. O'Toole's advisor, was
troubled when she came to him with concerns about the "tenor of life" in
Dr. Imanishi-Kari's laboratory, testifying that this was the third time she
had made such complaints within a short time of beginning a post-doctoral
position and this was the fourth such position she had held without publishing
any work. Tr. 2789-90. Also, Dr. O'Toole vigorously insisted in her contacts
with all the administrators and scientists at Tufts and MIT that she was not
alleging research fraud. See, e.g., Tr. 963, 1003 (O'Toole), 1716-17
(Woodland), 2794, 2487, 2856 (Wortis). Since the question about the "wells v.
clones" was raised by the time she met with Drs. Wortis and Huber, it is not
plausible that Dr. O'Toole would not have believed Dr. Imanishi-Kari guilty of
misconduct if Dr. O'Toole previously had been instructed by Dr. Imanishi-Kari
to lie about the very same point. At any rate, she would surely have told
about this episode immediately to convince the others of the seriousness of
the problem she perceived with the Table 2 data, and there is no evidence that
she did so. Instead, she portrayed herself from the beginning as shocked by
the apparent inconsistency of the 17 pages with reported data, which indicates
she expected until then that the data were consistent with the paper as she
read it. Cf. Tr. 929 (O'Toole). We find it more likely in light of this
history, that, in retrospect, Dr. O'Toole interpreted encouragement and
pressure to publish from Dr. Imanishi-Kari in the most ominous light, i.e., as
meaning she should publish at any cost including dishonesty.
136. The testimony of Dr. Wortis supported this conclusion, since he
described the distinction between "clone" and "subclone" as a chronological
question, depending on whether one had previously cloned the cells. Asked if
the terms were sometimes used "interchangeably," he stated that since
"operationally you're doing pretty much the same thing, in laboratory jargon,
you might go back and forth." Tr. 2750.
137. ORI argued that the data were probably fabricated in 1988 because
they were presented to the NIH Scientific Panel then "on the second day of a
two-day interview, after they raised questions on the first day about the
frequency data . . . ." ORI Br. 62. In addition, ORI argued that the data
must not have existed in 1986 or they would have been shown to Dr. O'Toole
when she raised questions about the June 6th retest of the Table 2 primary
hybridomas. ORI Br. 23-24. However, ORI later conceded that I-1:124-128A
"could have been fabricated in 1986" to show to Drs. Wortis, Woodland and
Huber in relation to the June 6th retest but argued that would only show that
Dr. Imanishi-Kari used the fabricated data on another occasion to deceive
others. ORI Br. 62, n.43. However, the concession also means that ORI
recognized that Drs. Wortis, Woodland, and Huber said that they reviewed the
data (as discussed elsewhere) and that they found the data adequately
supported the paper, whether or not Dr. O'Toole saw or accepted the data then.
138. It is interesting to observe that ORI here fell into the same use of
the terminology "clones" to refer to the products of the primary fusion for
which it charged Dr. Imanishi-Kari with misconduct, thus illustrating that
these terms are easily misused even after attention is drawn to the potential
for confusion.
139. Dr. Imanishi-Kari confirmed in an earlier interview that these data
were on paper from an MIT spiral notebook, and that at some point the pages
were removed. Ex. H103, at 49-50.
140. In light of such changes and the passage of time, it is not
particularly surprising that the participants at the meeting might have
difficulty describing exactly the subcloning data they saw. Dr. Huber was
mainly worried about the normal mouse data which appeared to contradict the
paper and relieved when that proved to be a mistyping, but she also testified
that she "understood the argument about the subcloning and that this was
important, that we had seen data for subcloning." Tr. 1805. ORI argued that
Dr. Huber mistakenly referred to the subcloning data as related to identifying
idiotype-positive þ antibodies. ORI FFCL III.E.10, citing Tr. 1781. Even if
her testimony is read to misstate this detail about the Table 2 subcloning
data, at the time she felt plainly that what she was shown was
"radioimmunoassay data [that] was sufficient to show that these hybridomas had
been subcloned." Tr. 1782. We found credible the testimony that all three
left satisfied that the issues had been resolved. See Tr. 1782, 1805 (Huber).
They were unlikely to have been satisfied on this issue if the data which they
saw had not related to the Table 2 issue which was before them.
141. Our conclusion that the participants in the meeting are accurate in
their consistent recollection of having seen the June subcloning data and that
Dr. O'Toole is mistaken in denying that this occurred is partly based on the
fact that Dr. O'Toole was not present the first time that Drs. Wortis, Huber,
and Woodland met with Dr. Imanishi-Kari. Dr. O'Toole's repeated assertions
that not only were the data not shown to anyone else but instead
Dr. Imanishi-Kari specifically announced to Dr. O'Toole that no such
subcloning was done is also undercut by a review of Dr. O'Toole's prior
memoranda on this subject. Dr. O'Toole wrote that, if one is not persuaded of
the inauthenticity of these data by the forensics or the peculiar results
(which, as discussed elsewhere, we are not), then "one is left with
contradictory assertions by Dr. Imanishi-Kari and myself." Ex. H282, at 2.
Previously, Dr. O'Toole declares, written statements of the other meeting
participants that they had seen the disputed data were accepted as accurate,
but "as I have told Drs. Kimes and Hadley [both then working with OSI, ORI's
predecessor], there is a tape recording of [the meeting participants']
assertions to the contrary." Id. Since no such tape recording was ever
produced to us and its absence was never explained, we can reasonably infer
that it either did not exist or did not support ORI's allegations. We
therefore give more credence to the mutually-corroborative testimony of the
other participants than to Dr. O'Toole's contradictory assertions.
142. Dr. Imanishi-Kari testified that at the time she considered this to
be a possible artifact of the gene insertion process but that since then the
phenomenon has been studied. Tr. 4876. In 1993, a scientific explanation
emerged, i.e., that sometimes hybridomas that were transgene negative
initially could later produce transgene-positive subclones because the
endogenous chromosomes were lost, permitting the expression of the previously
"silent" transgene. Tr. 4876-77; R. Br. 55, n.67. ORI quarreled with this
theory because ORI considered the idea incompatible with the observations of
many immunologists that chromosomes are lost, not gained, in subcloning. ORI
Br. 63. The new work does not suggest that new chromosomes are acquired but
rather that the loss of chromosomes may trigger expression of remaining
chromosomes.
143. Dr. Imanishi-Kari also pointed to another aspect of the June
subcloning data, i.e., that S444 (subclone 8) tested as strongly BET-1
positive (7300 cpm) but completely negative on the anti-æ assay (310 cpm),
which seems impossible since BET-1 tests for a subset of æ antibodies. Again,
this kind of peculiarity or error seems strange in data that is allegedly
fabricated to bolster the Table 2 claims after-the-fact (when
Dr. Imanishi-Kari should certainly have known what she was trying to prove).
144. For example, Dr. O'Toole's notebooks contain numerous examples of
shorthand entries for cpms (for example, using 5.0, 4.6, or 0.3), without any
underlying data being retained. See Exs. H18 and H19 passim.
145. Alternatively, the dashes which appear for the highlighted subclones
in the columns for the anti-æ probes could be negatives, indicating that
Dr. Imanishi-Kari simply was not interested even in relative values for these
subclones because there was no antibody production. This possibility is less
probable than the likelihood that the dashes indicate that these subclones
simply were not tested on the anti-æ probes, but if true, would mean that the
handwritten numbers are not a complete set of counts from a gamma counter--a
scenario which would also undercut ORI's premises.
146. A "Poisson distribution" refers generally to a distribution of values
about a mean in the form of a bell-shaped curve, in which the population mean
equals the population variance. Tr. 628-29 (Mosimann), 1481-82 (Gilbert),
1618-19 (McClure), Tr. 6087 (Speed); see also ORI Report 123, n.84. ORI
argued that a series of low background readings, such as the background
readings from a microliter plate in a fusion experiment, will be distributed
around multiple means and thus follow "mixtures" of Poisson distributions,
essentially a combination of a varying number of individual Poisson curves.
ORI Br. 72-73; ORI Report, App. B, at B-7; Tr. 738-740 (Mosimann), 837
(Barron), 1482-83, 1539-42 (Gilbert).
147. ORI did not find that any of the analyzed low counts fit a single
Poisson distribution.
148. "Standard deviation" (ë) measures the degree of dispersion of the
values in a sample from the mean of those values. Standard deviation is
calculated by dividing (a) the sum of the squares of the difference of each
value in the sample from the mean by (b) the sample size minus 1. This yields
the "sample variance"; the standard deviation is the square root of the sample
variance. In a Poisson distribution, the population mean equals the
population variance, so the standard deviation is the square root of the mean
of the values. It is thus possible to estimate what the dispersion of
multiple readings of a radioactive source around the mean of those readings
would be, where only one reading is obtained, by treating that reading as the
mean and taking its square root. Tr. 622-30 (Mosimann).
149. Perhaps because ORI had not originally offered Dr. Gilbert as a
witness who would address the Poisson distribution, the testimony ORI elicited
from Dr. Gilbert was general. He made four major points: (1) the decay of
radioactive atoms is an unpredictable, random event; (2) such randomness is
why statistical analyses have been used to detect fraud (because a fabricator
cannot reproduce random numbers accurately); (3) one would "expect" a certain
"spread" of data among background counts in an assay since background data are
"in principle the same empty tube . . . being counted over and over again;"
and (4) one might expect the final data to look like the sum of "several"
Poisson distributions if the experiment had several backgrounds. Tr. 1479-83,
1520-24, 1537-44. These points did not directly address our concerns here.
First, he described the randomness of radioactive decay as meaning that, if
one gets a count of 100, for example, in one minute, then counts again in the
next minute, one will not get the same number. Tr. 1480. Similarly, the
Beckman 300 manual states that, because radioactive decay is a random process,
it is unlikely that two successive measurements of the same sample would give
identical readings. Ex. H526, at 31. Such randomness, however, would affect
the order in which various counts are generated; ORI did not find non-
randomness in the order of the counts, but focused on the frequency of the
counts. The Poisson distribution may indicate some "spread" of data, as Dr.
Gilbert suggested, but also indicates that the mean and other values around
the mean will be generated more frequently than other values. Second, he did
not state how he knew that the randomness in radioactive decay has been used
to detect fraud elsewhere, nor specify how particular statistical methods were
applied there. Third, while Dr. Gilbert's testimony indicated that it did not
matter that the counts here were from multiple sources because background is
in principle the same empty tube being counted over and over again, he did not
explain how that principle would apply to counts under 600, which may or may
not be background. In fact, the backgrounds listed for the three assays at
issue here (two for each) were as low as 270, with the highest being 410, so
Dr. Mosimann's "low counts" could encompass values that are not background.
Moreover, the counts here are presented as counts of tubes which each may have
contributing radioactive components not only from the tube, but from the well
from a microliter plate put into the tube, anything sticking to the well, and
any contamination in the tube. While Dr. Gilbert recognized that there might
be several backgrounds due to different backgrounds in different tubes, he did
not address possible different contributing factors within a tube and how this
might affect the outcome. We also note that he first indicated one might
expect "several" mixtures, then amended this to "four or five" mixtures, then
amended this to "five or six mixtures." Tr. 1483, 1540, 1546. Yet, some of
the control sets fit to mixtures of seven or nine. Thus, we cannot accept his
testimony as establishing a scientific basis for how many mixtures should be
expected in the particular assays at issue here, even assuming such mixtures
should apply.
150. In order to determine whether given data fit Poisson mixture models,
ORI employed the chi-square goodness-of-fit test, a widely accepted technique
for measuring the difference between observed values (the sets of data) and
expected values (the Poisson models). The purpose of tests such as the chi-
square test is to show how likely it is that differences between observed data
and a model for such data can be explained on the basis of chance variation,
if the model is true. Tr. 754 (Mosimann), 6004-06 (Speed). The test involves
deriving a chi-square statistic based on the differences between the observed
and expected values and the degrees of freedom, a factor of the size of the
sample. The chi-square statistic is then compared with standard tables to
determining the chi-square probability value for a given data set at given
degrees of freedom. Tr. 754-58 (Mosimann); Exs. H413, H414, H415. To
determine whether or not a set of data fit a Poisson mixture model, ORI
employed a probability of .05, or 5%. In general, this means that if the chi-
square probability value obtained from comparing the data and the model is
less than .05, then there is only a 5% probability that the data fits the
model and that differences between the data and the model are due to chance
variation alone. Tr. 754-58 (Mosimann), 839-42 (Barron), 2311 (Speed). In
those cases, ORI concluded that the particular data set did not fit the
Poisson mixture model to which it was compared. Exs. H413, H414, H415.
Conversely, where the chi-square probability value for the data is more than
.05, or 5%, ORI concluded that the data fit the Poisson model. Exs. H413,
H414, H415.
151. Dr. Speed also disagreed that the statistical authority he cited for
the rule of 5 supported ORI's use of minimum expected values of less than 5 in
this case. He stated that this authority supported applying the "80%" variant
only to goodness-of-fit tests involving unimodal distributions, as opposed to
the multi-modal Poisson mixture distributions employed here. Tr. 2941-43.
152. ORI attempted to submit evidence that it had used statistical
analyses in scientific misconduct cases where a researcher admitted fraud
based on ORI's findings. We ruled that these cases are irrelevant to the
question of whether the particular analyses here are reliable to establish
fabrication where it is contested. Nothing in our decision suggests that ORI
may not continue to use such analyses in its investigations, however.
153. One of the control data sets was the counts from the tape in the left
column of the June subcloning data (the kappa/lambda probe). This set did not
fit the model, but Dr. Mosimann said that this was "probably due to the fact
that in the rounding protocol here, counts less than 1000 are rounded to the
nearest 10's." Tr. 791. He did not explain what this meant, but we note that
the handwritten results from the June subcloning include a higher percentage
of counts less than 1000 than this tape, and most of them were rounded to the
10's.
154. The Secret Service made an affirmative finding that both the blue and
the black pen ink used in writing on these pages were available on the
purported dates. Ex. H503, at 1. Nevertheless, both ORI and the Secret
Service witnesses concluded that the pages were "not produced at the time
purported." ORI Br. 64, citing Tr. 3236 (Hargett) and 4016 (Stewart).
155. The pages referenced (I-2:29, 34-35, 37-38, and 42-44) are dated June
3-28, 1985. Mr. Stewart testified that the ink from these pages matched among
themselves but did not match the ink from I-1:124-128. Tr. 3779; Exs. H503,
H533, H551.
156. For example, if the counter on which they were produced was only
acquired after 1985 or of a kind only available at Tufts to which
Dr. Imanishi-Kari had moved in July 1986, that would have strongly indicated
intentional fabrication after publication of the paper.
157. By 1988, she would have already moved to Tufts. On the one hand, had
she been fabricating these experiments, she might have recognized that she
needed to use counter tapes from her time at MIT, since those at Tufts might
noticeably differ. On the other hand, it seems less likely that tapes
supposedly dating from 1981-82 would be "lying about" after she had
reorganized her data for the move. Cf. ORI Reply Br. 20; Tr. 5126
(Imanishi-Kari).
158. Nor was there any evidence presented establishing that fusions were
performed in her laboratory as early as 1981-82 (the time frame for which the
Secret Service claimed matches for some of her green tapes) that would have
yielded this kind of counter tapes. Dr. Imanishi-Kari indicated that in her
years at MIT before 1984 she was mostly engaged in molecular work that did not
require use of the gamma counters. Ex. H103, at 33.
159. As discussed later, some Maplethorpe tapes were alleged to match over
a period of almost 21 months. Exs. H502 and H503. As Dr. Imanishi-Kari noted
in her brief, these tapes could not have been produced with a single ribbon,
and yet they all match in TLC ink analysis. R. Br. 25 and n.28.
160. While ORI questioned the idea that substitute printers were brought
in fairly often when printers broke down, ORI devoted a great deal of hearing
time to defending the possibility that printers could be switched between
entirely different types of counters: i.e., between a Packard beta and a
Beckman gamma. This claim became important because ORI relied on the match
with Maplethorpe tapes to suggest that the June subcloning tapes were not only
not produced within the exact month purported (i.e., not in June 1985), but
from a period too distant to have been simply accidentally misdated and in
fact before the transgenic mice existed. ORI Br. 69. However, the
Maplethorpe tapes were produced on a Packard beta counter while the I-1 tapes
were produced on a Beckman gamma counter. Yet if the tapes were merely
produced by printers with similar fonts hooked up to different counters, there
would be no reason to attribute any significance to whether their ribbons had
matching ink formulas. Hence, it was important that the same printer
generated all the tapes. The evidence in the record on the compatibility of
the printers in switching between different makes of counter machines (as
opposed to between the two Packards in the laboratory) was conflicting. A
Beckman representative suggested that the Beckman 7000T was probably
compatible in the mid-1980's, but did not know if other machines later were.
Tr. 5936, 5940-41 (Dahlgren). However, the persons at MIT who were
responsible for maintaining the counters seem to have believed (rightly or
wrongly) that such inter-make switching was problematic (unlike switching
printers between counters of the same make), so it not likely that they were
interchanged even if they could have been. See Tr. 4604, 4607-08 (Igras).
161. The reliance on the idea that only green tapes were relevant was
based on Mr. Stewart's assumption that once the color of tape was changed one
would expect the new color to remain in place for a substantial portion of the
succeeding pages. Tr. 3647. However, this assumption is inconsistent with
testimony that partial rolls and left-over ends would sometimes be used, which
might result in short runs of a different color. The brevity of the run might
be exaggerated in the existing record by the fact that most of the tapes were
not retained in any case. Eliminating from consideration yellow tapes from a
wider time frame may have resulted in overlooking a match in ink formula to a
date nearer in time to dates consistent with Dr. Imanishi-Kari's explanation
of her experiments.
162. Printer 1 would have been previously used to generate one set of
Maplethorpe, Pasternak and Reilly tapes from 1982-1984 (which match one of the
green tapes from the January fusion tapes); Printer 2 was previously used to
generate the Maplethorpe tapes found to be from 1981-82 (which match the June
subcloning tapes and the other January fusion green tapes).
163. The earlier green tapes could have been produced on either the same
printer or one with the same font, using, over the years, various ribbons each
with one of the two common ink formulas that recurred throughout the time
period. As noted, it is highly unlikely that the matches among the various
earlier tapes represent single ribbons over such long time frames, even
assuming that the substitute printer was used only sporadically.
164. We use the term "hybridoma" without further qualification in this
section for simplicity and to parallel the usage in the Cell paper.
165. The data at R-1:76-80 contained results of tests on supernatants of
108 normal spleen hybridomas and six normal lymph node hybridomas, the data at
I-1:106 contained results on 36 normal spleen hybridomas, and the data at I-
1:107 contained results on 94 normal lymph node hybridomas, for a total of 144
normal spleen and 100 normal lymph node hybridomas.
166. Another possibility is that the original entry was simply erroneous,
since Dr. Reis in other instances confused various Greek letters.
167. ORI pointed out that the control proteins were also changed (to
P8.56.7 from P8.86.9 and to P5.40.3(5) from an undiscernible notation). ORI
Br. 77. ORI offered no explanation of why it would benefit Dr. Imanishi-Kari
to make such changes in the control protein nomenclature other than to correct
mistakes in the original writing beyond vague speculation that perhaps the
original proteins were not "appropriate" for guinea pig anti-17.2.25. Tr.
364-66 (Dahlberg). No change was made to the control protein 17.2.25 which
clearly elicited the highest reaction. Dr. Imanishi-Kari's main point was
that the reaction to the 17.2.25 itself was most likely to be this
disproportionately strong if the coating reagent was anti-17.2.25.
168. Dr. Imanishi-Kari testified that for some purposes she used the
rabbit anti-124/40 intentionally to determine if the specific reactivity
occurring in endogenous idiotype-positive antibodies would resemble more
closely the pattern of 124/40 (which was encoded originally by a gene derived
from C57/BL6 normal mice) or the 17.2.25 (which was encoded by a gene from the
mice from which the transgene was derived). Dr. Imanishi-Kari's position that
the two reagents, while not identical, were very similar and could be
interchanged for at least some uses was supported by the testimony of several
witnesses. Tr. 2879-81, 2892-94 (Wortis), 3122-25, 3142-43 (Marrack). ORI
pointed to the work of Dr. Boersch-Supan, who testified that she explored and
published research (while in Dr. Imanishi-Kari's laboratory) showing that the
two reagents had molecular and serological differences. ORI Br. 79. However,
ORI ignored Dr. Boersch-Supan's testimony that they were very similar in the
idiotypic response and belonged to a highly homologous group of antibodies.
Tr. 1833-36. It is important to realize that the experiment at issue served
only to demonstrate the absence of idiotype-positivity in normal hybridomas
rather than to study particular patterns of idiotypic determinants. ORI did
not demonstrate that rabbit anti-124/40 would have been significantly
different for that purpose than the guinea pig anti-17.2.25. Absent such a
demonstration, no reason has been provided why Dr. Imanishi-Kari would attempt
to disguise the coating reagent.
| 2014-07-23T05:46:50 |
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|
https://lammps.sandia.gov/doc/bond_style.html
|
# bond_style command
## Syntax
bond_style style args
• style = none or hybrid or class2 or fene or fene/expand or harmonic or morse or nonlinear or quartic
args = none for any style except hybrid
hybrid args = list of one or more styles
## Examples
bond_style harmonic
bond_style fene
bond_style hybrid harmonic fene
## Description
Set the formula(s) LAMMPS uses to compute bond interactions between pairs of atoms. In LAMMPS, a bond differs from a pairwise interaction, which are set via the pair_style command. Bonds are defined between specified pairs of atoms and remain in force for the duration of the simulation (unless the bond breaks which is possible in some bond potentials). The list of bonded atoms is read in by a read_data or read_restart command from a data or restart file. By contrast, pair potentials are typically defined between all pairs of atoms within a cutoff distance and the set of active interactions changes over time.
Hybrid models where bonds are computed using different bond potentials can be setup using the hybrid bond style.
The coefficients associated with a bond style can be specified in a data or restart file or via the bond_coeff command.
All bond potentials store their coefficient data in binary restart files which means bond_style and bond_coeff commands do not need to be re-specified in an input script that restarts a simulation. See the read_restart command for details on how to do this. The one exception is that bond_style hybrid only stores the list of sub-styles in the restart file; bond coefficients need to be re-specified.
Note
When both a bond and pair style is defined, the special_bonds command often needs to be used to turn off (or weight) the pairwise interaction that would otherwise exist between 2 bonded atoms.
In the formulas listed for each bond style, r is the distance between the 2 atoms in the bond.
Here is an alphabetic list of bond styles defined in LAMMPS. Click on the style to display the formula it computes and coefficients specified by the associated bond_coeff command.
Click on the style to display the formula it computes, any additional arguments specified in the bond_style command, and coefficients specified by the associated bond_coeff command.
There are also additional accelerated pair styles included in the LAMMPS distribution for faster performance on CPUs, GPUs, and KNLs. The individual style names on the Commands bond doc page are followed by one or more of (g,i,k,o,t) to indicate which accelerated styles exist.
• none - turn off bonded interactions
• zero - topology but no interactions
• hybrid - define multiple styles of bond interactions
• class2 - COMPASS (class 2) bond
• fene - FENE (finite-extensible non-linear elastic) bond
• fene/expand - FENE bonds with variable size particles
• gromos - GROMOS force field bond
• harmonic - harmonic bond
• harmonic/shift - shifted harmonic bond
• harmonic/shift/cut - shifted harmonic bond with a cutoff
• mm3 - MM3 anharmonic bond
• morse - Morse bond
• nonlinear - nonlinear bond
• oxdna/fene - modified FENE bond suitable for DNA modeling
• oxdna2/fene - same as oxdna but used with different pair styles
• quartic - breakable quartic bond
• table - tabulated by bond length
## Restrictions
Bond styles can only be set for atom styles that allow bonds to be defined.
Most bond styles are part of the MOLECULE package. They are only enabled if LAMMPS was built with that package. See the Build package doc page for more info. The doc pages for individual bond potentials tell if it is part of a package.
bond_style none
| 2019-02-17T11:03:49 |
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|
https://dlmf.nist.gov/9.5
|
# §9.5 Integral Representations
## §9.5(i) Real Variable
9.5.1 $\mathrm{Ai}\left(x\right)=\frac{1}{\pi}\int_{0}^{\infty}\cos\left(\tfrac{1}{3}% t^{3}+xt\right)\mathrm{d}t.$ ⓘ Symbols: $\mathrm{Ai}\left(\NVar{z}\right)$: Airy function, $\pi$: the ratio of the circumference of a circle to its diameter, $\cos\NVar{z}$: cosine function, $\mathrm{d}\NVar{x}$: differential of $x$, $\int$: integral and $x$: real variable Source: Olver (1997b, p. 53) A&S Ref: 10.4.32 (in different form) Permalink: http://dlmf.nist.gov/9.5.E1 Encodings: TeX, pMML, png See also: Annotations for 9.5(i), 9.5 and 9
9.5.2 $\mathrm{Ai}\left(-x\right)=\frac{x^{\ifrac{1}{2}}}{\pi}\int_{-1}^{\infty}\cos% \left(x^{\ifrac{3}{2}}(\tfrac{1}{3}t^{3}+t^{2}-\tfrac{2}{3})\right)\mathrm{d}t,$ $x>0$. ⓘ Symbols: $\mathrm{Ai}\left(\NVar{z}\right)$: Airy function, $\pi$: the ratio of the circumference of a circle to its diameter, $\cos\NVar{z}$: cosine function, $\mathrm{d}\NVar{x}$: differential of $x$, $\int$: integral and $x$: real variable Source: Olver (1997b, p. 103) A&S Ref: 10.4.32 (in different form) Permalink: http://dlmf.nist.gov/9.5.E2 Encodings: TeX, pMML, png See also: Annotations for 9.5(i), 9.5 and 9
9.5.3 $\mathrm{Bi}\left(x\right)=\frac{1}{\pi}\int_{0}^{\infty}\exp\left(-{\tfrac{1}{% 3}}t^{3}+xt\right)\mathrm{d}t+\frac{1}{\pi}\int_{0}^{\infty}\sin\left(\tfrac{1% }{3}t^{3}+xt\right)\mathrm{d}t.$ ⓘ Symbols: $\mathrm{Bi}\left(\NVar{z}\right)$: Airy function, $\pi$: the ratio of the circumference of a circle to its diameter, $[\NVar{a},\NVar{b})$: half-closed interval, $\mathrm{d}\NVar{x}$: differential of $x$, $\exp\NVar{z}$: exponential function, $\mathrm{e}$: base of natural logarithm, $\int$: integral, $(\NVar{a},\NVar{b}]$: half-closed interval, $\sin\NVar{z}$: sine function and $x$: real variable Source: Use (9.5.5) with the substitions: for the paths $(-\infty,0]$ use $t=-\tau$, for the paths $[0,\infty{\mathrm{e}^{\pm\pi\mathrm{i}/3}})$ use $t={\mathrm{e}^{\pm\pi\mathrm{i}/3}}\tau$. For the resulting integrals use (4.14.1) and (4.14.2). A&S Ref: 10.4.33 Referenced by: 9.12.19 Permalink: http://dlmf.nist.gov/9.5.E3 Encodings: TeX, pMML, png See also: Annotations for 9.5(i), 9.5 and 9
9.5.4 $\mathrm{Ai}\left(z\right)=\frac{1}{2\pi i}\int_{\infty e^{-\pi i/3}}^{\infty e% ^{\pi i/3}}\exp\left(\tfrac{1}{3}t^{3}-zt\right)\mathrm{d}t,$
9.5.5 $\mathrm{Bi}\left(z\right)=\frac{1}{2\pi}\int_{-\infty}^{\infty e^{\pi i/3}}% \exp\left(\tfrac{1}{3}t^{3}-zt\right)\mathrm{d}t+\dfrac{1}{2\pi}\int_{-\infty}% ^{\infty e^{-\pi i/3}}\exp\left(\tfrac{1}{3}t^{3}-zt\right)\mathrm{d}t.$
9.5.6 $\mathrm{Ai}\left(z\right)=\frac{\sqrt{3}}{2\pi}\int_{0}^{\infty}\exp\left(-% \frac{t^{3}}{3}-\frac{z^{3}}{3t^{3}}\right)\mathrm{d}t,$ $|\operatorname{ph}z|<\tfrac{1}{6}\pi$. ⓘ Symbols: $\mathrm{Ai}\left(\NVar{z}\right)$: Airy function, $\pi$: the ratio of the circumference of a circle to its diameter, $\mathrm{d}\NVar{x}$: differential of $x$, $\exp\NVar{z}$: exponential function, $\int$: integral, $\operatorname{ph}$: phase and $z$: complex variable Source: Reid (1995, (5.4), p. 170, with change of variable and using analytic continuation to complex $z$) Referenced by: Changes Permalink: http://dlmf.nist.gov/9.5.E6 Encodings: TeX, pMML, png Clarification (effective with 1.0.15): The validity constraint $|\operatorname{ph}z|<\tfrac{1}{6}\pi$ was added. See also: Annotations for 9.5(ii), 9.5 and 9
9.5.7 $\mathrm{Ai}\left(z\right)=\frac{e^{-\zeta}}{\pi}\int_{0}^{\infty}\exp\left(-z^% {\ifrac{1}{2}}t^{2}\right)\cos\left(\tfrac{1}{3}t^{3}\right)\mathrm{d}t,$ $|\operatorname{ph}z|<\pi$.
9.5.8 $\mathrm{Ai}\left(z\right)=\frac{e^{-\zeta}\zeta^{\ifrac{-1}{6}}}{\sqrt{\pi}(48% )^{\ifrac{1}{6}}\Gamma\left(\frac{5}{6}\right)}\int_{0}^{\infty}e^{-t}t^{-% \ifrac{1}{6}}\left(2+\frac{t}{\zeta}\right)^{-\ifrac{1}{6}}\mathrm{d}t,$ $|\operatorname{ph}z|<\frac{2}{3}\pi$.
In (9.5.7) and (9.5.8) $\zeta=\frac{2}{3}z^{\ifrac{3}{2}}$.
| 2018-06-20T20:54:48 |
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|
https://math-physics-problems.wikia.org/wiki/Annuities
|
267 Pages
## Problem
An annuity is a series of regular payments that are put into an investment that grows with compounded interest (essentially the sum of compound interest over time). Most books state the annuity formula as
$S_n = \frac{R\left[{\left(1 + i \right)}^{n} - 1 \right]}{i}$.
Part 1: A father decides to put $50 at the end of each month in his son's college fund. The interest rate is 3.6% compounded monthly. If his son turns five years old today, how much money will be in the fund when he turns 18 years old? How much more money will be in the fund compared to the situation with no interest rate? Part 2: If the father wanted to save$20000 instead of the result in part 1, how much should he put in at the end of each month?
Bonus problem
Begin with the compound interest formula $S = R(1+i)^n$. Derive the annuity formula.
## Solution
Part 1
The payment is $50, so$ R = 50 $. The interest rate is compounded monthly, so$ i = \frac{0.036}{12} = 0.003 $. The number of payments across 13 years (ages 5 - 18) is$ n = 13(12) = 156 $. Thus,$ {S}_{156} = \frac{50\left[{\left(1 + 0.003 \right)}^{156} - 1 \right]}{0.003} {S}_{156} = 9927.98466 $. The son will have$9927.98 saved up for college by his 18th birthday.
If the "annuity" had no interest,
${S}_{156} = 50(156) = 7800$.
Subtracting this result to the result with 3.6% interest rate yields
$9927.98 - 7800 = 2127.98$.
The interest rate of the annuity contributed an additional $2127.98 to the college fund. Part 2$ 20000 = \frac{R\left[{\left(1 + 0.003 \right)}^{156} - 1 \right]}{0.003} R = \frac{2000(0.003)}{\left[{\left(1 + 0.003 \right)}^{156} - 1 \right]} R = \frac{60}{0.595679} R = 100.7253907 $The father should put in$100.73 at the end of each month to reach $20000 by the time his son turns 18. Bonus problem On the first payment$ S_0 = R $. On the second payment$ S_1 = R $, and the first payment grew due to interest$ S_0 = R(1+i) $. This recursive pattern continues for$ n $payments$ [0,n-1] $,$ S_n = S_0 + S_1 + S_3 + ... + {S}_{n-1} S_n = R{(1+i)}^{n-1} + ... + R(1+i) + R $. Using the geometric series formula$ \sum_{k=0}^{n-1} ar^k = \frac{a(r^n - 1 )}{r-1} $, where$ a = R $and$ r = (1+i) S_n = \frac{R((1+i)^n - 1 )}{(1+i)-1} $. Therefore,$ S_n = \frac{R((1+i)^n - 1 )}{i} \$.
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| 2020-11-29T01:51:02 |
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http://cordis.europa.eu/result/rcn/193531_en.html
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# Community Research and Development Information Service - CORDIS
## Final Report Summary - DIMENSION (The Role of Dimension in Metric Embedding)
This project deals with the theory of \emph{low-distortion embedding} of finite metric spaces. Metric embedding can be a useful and versatile algorithmic tool, in particular for approximating combinatorial optimization problems, and in any application area that requires classification and organization of data whose features bear some geometry.
A typical problem in this field is understanding how faithfully a metric space can be represented as a subset of a normed space. Normed spaces are very natural candidates for embedding questions, since they carry additional structure that may be exploited in algorithms and data structures.
An important parameter of an embedding is the \emph{dimension} of the host normed space. The dimension plays a major role in application areas, because it determines the size of the representation, and because the running time of many algorithms depends inherently on the dimension.
In this research project, I am mainly working on developing a better understanding on the dimension required in different embedding settings, focusing on doubling metrics.
In the beginning of the project I published a paper with Assaf Naor called "Assouad's Theorem with Dimension Independent of the Snowflaking". The main result of this paper is a strengthening of a classical theorem of Assouad from '83, we show that any $(1-\epsilon)$ snowflake of a doubling metric embeds into Euclidean space with distortion $\tilde{O}(1/\epsilon)$ using only $O(1)$ dimensions (in Assouad's result, and in all of its subsequent improvements, the dimension depends on $\epsilon$).
One of the main goals of the research program, is to understand whether the dependence on $\epsilon$ can be improved, and in general try to obtain distortion $O(1/\sqrt{\epsilon})$, which translate to distortion $O(\sqrt{\log n})$ for arbitrary doubling metrics on $n$ points. These are Problems \ref{pr:1} and \ref{pr:4} in the project. The first step described there, is to study embedding of one of the "bad examples" for low dimensional embedding - the so called Laakso graph.
I found a satisfying answer to this question, which appears in the paper titled "Low Dimensional Embedding of Doubling Metrics". There I showed that the best distortion achievable for embedding this graph into Euclidean space, which is $O(\log n)$, can also be obtained in constant dimension (in particular, dimension 3). Additionally, I presented in that paper several improvements and simplifications of low distortion embedding of doubling metrics and their snowflakes into $\ell_p$. In particular, I showed a simple proof with the best possible dependence on the parameters, for embedding doubling metrics with arbitrarily small distortion of $1+\delta$ into $\ell_\infty$, where the host dimension is the (asymptotically) best possible.
One of the main open problems in the field of metric embedding, is whether there exists a dimension reduction in Euclidean space tailored for doubling metrics (that provides constant distortion using constant dimension). This is \probref{pr:3} in the project, which is very challenging. In an attempt to attack this problem, with Lee-Ad Gottlieb and Yair Bartal, we show in the paper "On the Impossibility of Dimension Reduction for Doubling Subsets of $\ell_p$", that its counterpart in $\ell_p$ for any $p>2$ is impossible. That is, there is no dimensionality reduction for doubling subsets of $\ell_p$ for $p>2$. (The same result, using completely different techniques, was obtain concurrently by Lafforge and Naor).
I also worked on other related problems in the field of metric embedding. For instance, in the paper "Cops, Robbers, and Threatening Skeletons: Padded Decomposition for Minor-Free Graphs" I and my co-authors show an improved decomposition theorem for minor-free graphs, which in turn implies improved embedding of such graphs into $\ell_1$. In an additional paper called "Light Spanners", we show that every metric has $t$-spanner (a graph that preserves distances upto a factor of $t$), with few edges and small total weight (sum of edge weights). Such spanners are a useful object in some distributed setting, network design, and routing.
In a sequence of works with my student Arnold Filtser and Colleague Michael Elkin, we study relaxed notions of embedding, that allow improved distortion and dimension for some of the pairs. In particular, in our paper "Terminal Embeddings" we assume the input consists of a metric and a subset of k important points called terminals. Then we would like to obtain a low dimensional embedding that preserves well distance from terminals to all other points -- where both distortion and dimension should depend on k only (regardless of the input size). We show the applicability of this notion in various algorithmic settings, e.g. approximation algorithms and online algorithms. In our paper "Prioritized Metric Structures and Embedding" we generalize the notion of terminal embedding, and propose a scheme where a priority ranking over the points is given, then one desires an embedding with guarantees that scale with the ranking of the points. We extend these ideas beyond embedding, into related algorithmic tasks such as approximate distance oracles and compact routing schemes, that has prioritized stretch and label size guarantees. Roughly speaking, the stretch corresponds to distortion, and the label size to dimension. With Arnold Filtser and Yair Bartal we continue to study these new notions, and in our paper "On Notions of Distortion and an Almost Minimum Spanning Tree with Constant Average Distortion" we show that they have some similarity to previously defined notions of scaling distortion. We also construct spanners with prioritized distortion, and as a corollary obtain that each graph contains a spanning tree with weight arbitrarily close to that of the minimum spanning tree, and that also possesses constant average distortion. All these result interplay nicely with the main theme of the proposal -- to understand under what circumstances one can obtain low dimensional representation of data, with low distortion.
With Michael Elkin I had several works on succinct data structure for representing metrics -- we had a paper "On Efficient Distributed Construction of Near Optimal Routing Schemes", which construct in a distributed manner a routing scheme that can route message on almost shortest paths, which needs low storage at every vertex. In our paper "Hopsets with Constant Hopbound, and Applications to Approximate Shortest Paths" we study the notion of hopsets, in which one wants to augment the input graph with a small number of edges, and maintain almost shortest paths with path consisting of few edges. We also had a paper "Distributed Strong Diameter Network Decomposition" for network decomposition, which is basic partitioning framework useful in many distributed tasks. Very recently we published "Efficient Algorithms for Constructing Very Sparse Spanners and Emulators", in which we improve the state-of-the-art for near linear time algorithms for spanners.
In a recent paper with Alex Andoni and Assaf Naor, "Impossibility of Sketching of the 3D Transportation Metric with Quadratic Cost", we study transportation metrics. These metrics play a vital role in vision and image processing, and have numerous other applications. We provide both lower and upper bounds on the embeddability of such metrics into Euclidean space and L1, and also give lower bounds on low dimensional representation of such metrics, known as sketches. Again this work lies in the main theme of the proposal -- understanding the dimensionality of various metrics.
In a submitted paper with Yair Bartal and Nova Fandina, we study refined notions of distortion in dimension reduction in Euclidean space. We prove that the classical JL dimension reduction lemma has bounded moments of distortion even using dimension much smaller than logarithmic in the number of points, and show relations to other dimension reduction objective studied in the literature, such as Stress and Energy. We also exhibit some algorithmic applications of our techniques.
## Reported by
BEN-GURION UNIVERSITY OF THE NEGEV
Israel
## Subjects
Scientific Research
Follow us on: Managed by the EU Publications Office Top
| 2017-10-17T08:43:35 |
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https://par.nsf.gov/biblio/10232679-exploring-contamination-des-y1-cluster-sample-spt-sz-selected-clusters
|
Exploring the contamination of the DES-Y1 cluster sample with SPT-SZ selected clusters
ABSTRACT We perform a cross validation of the cluster catalogue selected by the red-sequence Matched-filter Probabilistic Percolation algorithm (redMaPPer) in Dark Energy Survey year 1 (DES-Y1) data by matching it with the Sunyaev–Zel’dovich effect (SZE) selected cluster catalogue from the South Pole Telescope SPT-SZ survey. Of the 1005 redMaPPer selected clusters with measured richness $\hat{\lambda }\gt 40$ in the joint footprint, 207 are confirmed by SPT-SZ. Using the mass information from the SZE signal, we calibrate the richness–mass relation using a Bayesian cluster population model. We find a mass trend λ ∝ MB consistent with a linear relation (B ∼ 1), no significant redshift evolution and an intrinsic scatter in richness of σλ = 0.22 ± 0.06. By considering two error models, we explore the impact of projection effects on the richness–mass modelling, confirming that such effects are not detectable at the current level of systematic uncertainties. At low richness SPT-SZ confirms fewer redMaPPer clusters than expected. We interpret this richness dependent deficit in confirmed systems as due to the increased presence at low richness of low-mass objects not correctly accounted for by our richness-mass scatter model, which we call contaminants. At a richness $\hat{\lambda }=40$, this population makes up ${\gt}12{{\ \rm per\ cent}}$ more »
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
Award ID(s):
Publication Date:
NSF-PAR ID:
10232679
Journal Name:
Monthly Notices of the Royal Astronomical Society
Volume:
504
Issue:
1
Page Range or eLocation-ID:
1253 to 1272
ISSN:
0035-8711
3. ABSTRACT Previous work has argued that atomic gas mass estimates of galaxies from 21-cm H i emission are systematically low due to a cold opaque atomic gas component. If true, this opaque component necessitates a $\sim 35{{\ \rm per\ cent}}$ correction factor relative to the mass from assuming optically thin H i emission. These mass corrections are based on fitting H i spectra with a single opaque component model that produces a distinct ‘top-hat’ shaped line profile. Here, we investigate this issue using deep, high spectral resolution H i VLA observations of M31 and M33 to test if these top-hat profiles are instead superpositionsmore »
| 2022-08-07T21:54:57 |
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https://zbmath.org/authors/?q=ai%3Adoungmo-goufo.emile-franc
|
zbMATH — the first resource for mathematics
Doungmo Goufo, Emile Franc
Compute Distance To:
Author ID: doungmo-goufo.emile-franc Published as: Doungmo Goufo, E. F.; Doungmo Goufo, Emile F.; Doungmo Goufo, Emile Franc; Doungmo Goufo, Emile Franck; Goufo, Emile F. Doungmo; Goufo, Emile Franc Doungmo Homepage: http://www.unisa.ac.za/default.asp?Cmd=ViewContent&ContentID=96580 External Links: MGP · Wikidata · ORCID · ResearchGate · dblp
Documents Indexed: 48 Publications since 2013
all top 5
Co-Authors
13 single-authored 6 Atangana, Abdon 6 Mugisha, Stella 6 Oukouomi Noutchie, Suares Clovis 4 Khumalo, Melusi 3 Maritz, Riëtte 2 Kamga Pene, Morgan 2 Kamga Pene, Morgan M. 2 Kubeka, Amos S. 2 Kumar, Sunil 2 Mwambakana, Jeanine N. 2 Tchangou Toudjeu, Ignace 1 Djomegni, Patrick M. Tchepmo 1 Ghosh, Surath 1 Govinder, Keshlan Sathasiva 1 Khan, Yasir 1 Mbehou, Mohamed 1 Moremedi, G. M. 1 Munganga, Justin Manango W. 1 Nieto Roig, Juan Jose 1 Samet, Bessem 1 Tabi, Conrad Bertrand 1 Tchepmo Djomegni, Patrick Mimphis 1 Tenkam, H. M.
all top 5
Serials
8 Mathematical Problems in Engineering 6 Chaos, Solitons and Fractals 3 Chaos 3 Discrete and Continuous Dynamical Systems. Series S 3 Journal of Nonlinear Science and Applications 2 Mathematical Methods in the Applied Sciences 2 International Journal of Bifurcation and Chaos in Applied Sciences and Engineering 2 Abstract and Applied Analysis 2 Open Mathematics 1 Journal of Computational and Applied Mathematics 1 Acta Mathematicae Applicatae Sinica. English Series 1 Japan Journal of Industrial and Applied Mathematics 1 Computational and Applied Mathematics 1 Turkish Journal of Mathematics 1 Fractional Calculus & Applied Analysis 1 Communications in Nonlinear Science and Numerical Simulation 1 Nonlinear Dynamics and Systems Theory 1 Comptes Rendus. Mathématique. Académie des Sciences, Paris 1 Advances in Difference Equations 1 ISRN Mathematical Analysis 1 Journal of Theoretical Biology 1 Journal of Mathematics 1 Journal of Function Spaces
all top 5
Fields
19 Partial differential equations (35-XX) 17 Ordinary differential equations (34-XX) 14 Real functions (26-XX) 11 Dynamical systems and ergodic theory (37-XX) 10 Numerical analysis (65-XX) 9 Special functions (33-XX) 9 Biology and other natural sciences (92-XX) 6 Statistical mechanics, structure of matter (82-XX) 5 Fluid mechanics (76-XX) 3 Integral equations (45-XX) 3 Operator theory (47-XX) 2 Measure and integration (28-XX) 2 Relativity and gravitational theory (83-XX) 2 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 1 Harmonic analysis on Euclidean spaces (42-XX) 1 Calculus of variations and optimal control; optimization (49-XX) 1 Optics, electromagnetic theory (78-XX) 1 Geophysics (86-XX)
Citations contained in zbMATH Open
31 Publications have been cited 186 times in 91 Documents Cited by Year
Chaotic processes using the two-parameter derivative with non-singular and non-local kernel: basic theory and applications. Zbl 1378.34011
Doungmo Goufo, Emile Franc
2016
A biomathematical view on the fractional dynamics of cellulose degradation. Zbl 1316.26004
Doungmo Goufo, Emile Franc
2015
Stability and convergence analysis of a variable order replicator-mutator process in a moving medium. Zbl 1343.92340
Doungmo Goufo, Emile Franc
2016
Attractors for fractional differential problems of transition to turbulent flows. Zbl 1440.76038
Doungmo Goufo, Emile F.; Nieto, Juan J.
2018
Some properties of the Kermack-McKendrick epidemic model with fractional derivative and nonlinear incidence. Zbl 1344.92160
Doungmo Goufo, Emile Franc; Maritz, Riëtte; Munganga, Justin
2014
Speeding up chaos and limit cycles in evolutionary language and learning processes. Zbl 1417.91426
Goufo, Emile Franc Doungmo
2017
Duplication in a model of rock fracture with fractional derivative without singular kernel. Zbl 1347.26019
Doungmo Goufo, Emile F.; Pene, Morgan Kamga; Mwambakana, Jeanine N.
2015
Solvability of chaotic fractional systems with 3D four-scroll attractors. Zbl 1380.34110
Doungmo Goufo, Emile Franc
2017
Global solvability of a continuous model for nonlocal fragmentation dynamics in a moving medium. Zbl 1296.35022
Doungmo Goufo, E. F.; Oukouomi Noutchie, S. C.
2013
A mathematical analysis of fractional fragmentation dynamics with growth. Zbl 1433.35444
Doungmo Goufo, Emile Franc
2014
Strange attractor existence for non-local operators applied to four-dimensional chaotic systems with two equilibrium points. Zbl 1409.37043
Doungmo Goufo, Emile F.
2019
Honesty in discrete, nonlocal and randomly position structured fragmentation model with unbounded rates. Zbl 1396.82009
Doungmo Goufo, Emile Franc; Oukouomi Noutchie, Suares Clovis
2013
Global analysis of a discrete nonlocal and nonautonomous fragmentation dynamics occurring in a moving process. Zbl 1381.35017
Doungmo Goufo, E. F.; Oukouomi Noutchie, S. C.
2013
Stability analysis of epidemic models of Ebola hemorrhagic fever with non-linear transmission. Zbl 1345.92139
Doungmo Goufo, Emile Franc; Kamga Pene, Morgan; Mugisha, Stella
2016
Extension of matched asymptotic method to fractional boundary layers problems. Zbl 1407.34005
Atangana, Abdon; Doungmo Goufo, Emile Franc
2014
On the honesty in nonlocal and discrete fragmentation dynamics in size and random position. Zbl 1286.35239
Oukouomi Noutchie, Suares Clovis; Doungmo Goufo, Emile Franc
2013
An analysis for heat equations arises in diffusion process using new Yang-Abdel-Aty-Cattani fractional operator. Zbl 1452.35242
Kumar, Sunil; Ghosh, Surath; Samet, Bessem; Goufo, Emile Franc Doungmo
2020
A peculiar application of Atangana-Baleanu fractional derivative in neuroscience: chaotic burst dynamics. Zbl 1416.92036
Doungmo Goufo, Emile F.; Mbehou, Mohamed; Kamga Pene, Morgan M.
2018
On chaotic models with hidden attractors in fractional calculus above power law. Zbl 1448.34014
Doungmo Goufo, Emile Franc
2019
Mathematical analysis of peculiar behavior by chaotic, fractional and strange multiwing attractors. Zbl 1401.34008
Doungmo Goufo, Emile Franc
2018
Approximation result for non-autonomous and non-local rock fracture models. Zbl 06859022
Doungmo Goufo, E. F.; Kubeka, A.
2018
Evolution equations with a parameter and application to transport-convection differential equations. Zbl 1424.35338
Doungmo Goufo, Emile Franc
2017
A model of the groundwater flowing within a leaky aquifer using the concept of local variable order derivative. Zbl 1330.76128
Atangana, Abdon; Goufo, Emile Franc Doungmo
2015
The proto-Lorenz system in its chaotic fractional and fractal structure. Zbl 1452.37086
Doungmo Goufo, Emile Franc
2020
Conservatory of Kaup-Kupershmidt equation to the concept of fractional derivative with and without singular kernel. Zbl 1393.35198
Atangana, Abdon; Goufo, Emile Franc Doungmo
2018
Shallow water wave models with and without singular kernel: existence, uniqueness, and similarities. Zbl 1426.35223
Doungmo Goufo, Emile Franc; Kumar, Sunil
2017
On analysis of fractional Navier-Stokes equations via nonsingular solutions and approximation. Zbl 1394.35551
Doungmo Goufo, Emile Franc; Mugisha, Stella
2015
Positivity and contractivity in the dynamics of clusters’ splitting with derivative of fractional order. Zbl 06632213
Doungmo Goufo, Emile Franc; Mugisha, Stella
2015
A fractional SEIR epidemic model for spatial and temporal spread of measles in metapopulations. Zbl 1406.92566
Doungmo Goufo, Emile Franc; Oukouomi Noutchie, Suares Clovis; Mugisha, Stella
2014
Mathematical solvability of a Caputo fractional polymer degradation model using further generalized functions. Zbl 1407.82069
Doungmo Goufo, Emile Franc; Mugisha, Stella
2014
Existence results for a Michaud fractional, nonlocal, and randomly position structured fragmentation model. Zbl 1407.35206
Doungmo Goufo, Emile Franc; Maritz, Riëtte; Mugisha, Stella
2014
An analysis for heat equations arises in diffusion process using new Yang-Abdel-Aty-Cattani fractional operator. Zbl 1452.35242
Kumar, Sunil; Ghosh, Surath; Samet, Bessem; Goufo, Emile Franc Doungmo
2020
The proto-Lorenz system in its chaotic fractional and fractal structure. Zbl 1452.37086
Doungmo Goufo, Emile Franc
2020
Strange attractor existence for non-local operators applied to four-dimensional chaotic systems with two equilibrium points. Zbl 1409.37043
Doungmo Goufo, Emile F.
2019
On chaotic models with hidden attractors in fractional calculus above power law. Zbl 1448.34014
Doungmo Goufo, Emile Franc
2019
Attractors for fractional differential problems of transition to turbulent flows. Zbl 1440.76038
Doungmo Goufo, Emile F.; Nieto, Juan J.
2018
A peculiar application of Atangana-Baleanu fractional derivative in neuroscience: chaotic burst dynamics. Zbl 1416.92036
Doungmo Goufo, Emile F.; Mbehou, Mohamed; Kamga Pene, Morgan M.
2018
Mathematical analysis of peculiar behavior by chaotic, fractional and strange multiwing attractors. Zbl 1401.34008
Doungmo Goufo, Emile Franc
2018
Approximation result for non-autonomous and non-local rock fracture models. Zbl 06859022
Doungmo Goufo, E. F.; Kubeka, A.
2018
Conservatory of Kaup-Kupershmidt equation to the concept of fractional derivative with and without singular kernel. Zbl 1393.35198
Atangana, Abdon; Goufo, Emile Franc Doungmo
2018
Speeding up chaos and limit cycles in evolutionary language and learning processes. Zbl 1417.91426
Goufo, Emile Franc Doungmo
2017
Solvability of chaotic fractional systems with 3D four-scroll attractors. Zbl 1380.34110
Doungmo Goufo, Emile Franc
2017
Evolution equations with a parameter and application to transport-convection differential equations. Zbl 1424.35338
Doungmo Goufo, Emile Franc
2017
Shallow water wave models with and without singular kernel: existence, uniqueness, and similarities. Zbl 1426.35223
Doungmo Goufo, Emile Franc; Kumar, Sunil
2017
Chaotic processes using the two-parameter derivative with non-singular and non-local kernel: basic theory and applications. Zbl 1378.34011
Doungmo Goufo, Emile Franc
2016
Stability and convergence analysis of a variable order replicator-mutator process in a moving medium. Zbl 1343.92340
Doungmo Goufo, Emile Franc
2016
Stability analysis of epidemic models of Ebola hemorrhagic fever with non-linear transmission. Zbl 1345.92139
Doungmo Goufo, Emile Franc; Kamga Pene, Morgan; Mugisha, Stella
2016
A biomathematical view on the fractional dynamics of cellulose degradation. Zbl 1316.26004
Doungmo Goufo, Emile Franc
2015
Duplication in a model of rock fracture with fractional derivative without singular kernel. Zbl 1347.26019
Doungmo Goufo, Emile F.; Pene, Morgan Kamga; Mwambakana, Jeanine N.
2015
A model of the groundwater flowing within a leaky aquifer using the concept of local variable order derivative. Zbl 1330.76128
Atangana, Abdon; Goufo, Emile Franc Doungmo
2015
On analysis of fractional Navier-Stokes equations via nonsingular solutions and approximation. Zbl 1394.35551
Doungmo Goufo, Emile Franc; Mugisha, Stella
2015
Positivity and contractivity in the dynamics of clusters’ splitting with derivative of fractional order. Zbl 06632213
Doungmo Goufo, Emile Franc; Mugisha, Stella
2015
Some properties of the Kermack-McKendrick epidemic model with fractional derivative and nonlinear incidence. Zbl 1344.92160
Doungmo Goufo, Emile Franc; Maritz, Riëtte; Munganga, Justin
2014
A mathematical analysis of fractional fragmentation dynamics with growth. Zbl 1433.35444
Doungmo Goufo, Emile Franc
2014
Extension of matched asymptotic method to fractional boundary layers problems. Zbl 1407.34005
Atangana, Abdon; Doungmo Goufo, Emile Franc
2014
A fractional SEIR epidemic model for spatial and temporal spread of measles in metapopulations. Zbl 1406.92566
Doungmo Goufo, Emile Franc; Oukouomi Noutchie, Suares Clovis; Mugisha, Stella
2014
Mathematical solvability of a Caputo fractional polymer degradation model using further generalized functions. Zbl 1407.82069
Doungmo Goufo, Emile Franc; Mugisha, Stella
2014
Existence results for a Michaud fractional, nonlocal, and randomly position structured fragmentation model. Zbl 1407.35206
Doungmo Goufo, Emile Franc; Maritz, Riëtte; Mugisha, Stella
2014
Global solvability of a continuous model for nonlocal fragmentation dynamics in a moving medium. Zbl 1296.35022
Doungmo Goufo, E. F.; Oukouomi Noutchie, S. C.
2013
Honesty in discrete, nonlocal and randomly position structured fragmentation model with unbounded rates. Zbl 1396.82009
Doungmo Goufo, Emile Franc; Oukouomi Noutchie, Suares Clovis
2013
Global analysis of a discrete nonlocal and nonautonomous fragmentation dynamics occurring in a moving process. Zbl 1381.35017
Doungmo Goufo, E. F.; Oukouomi Noutchie, S. C.
2013
On the honesty in nonlocal and discrete fragmentation dynamics in size and random position. Zbl 1286.35239
Oukouomi Noutchie, Suares Clovis; Doungmo Goufo, Emile Franc
2013
all top 5
all top 5
Cited in 41 Serials
15 Chaos, Solitons and Fractals 7 Chaos 7 Advances in Difference Equations 4 Mathematical Problems in Engineering 4 Fractional Calculus & Applied Analysis 4 Journal of Function Spaces 3 International Journal of Bifurcation and Chaos in Applied Sciences and Engineering 2 Mathematical Biosciences 2 Mathematical Methods in the Applied Sciences 2 Journal of Computational and Applied Mathematics 2 Computational and Applied Mathematics 2 Complexity 2 Comptes Rendus. Mathématique. Académie des Sciences, Paris 2 Discrete and Continuous Dynamical Systems. Series S 2 Journal of Mathematics 2 Open Mathematics 1 Journal of Computational Physics 1 Physica A 1 Bulletin of Mathematical Biology 1 Acta Mathematicae Applicatae Sinica. English Series 1 Japan Journal of Industrial and Applied Mathematics 1 Numerical Algorithms 1 SIAM Journal on Applied Mathematics 1 SIAM Review 1 Archives of Control Sciences 1 Turkish Journal of Mathematics 1 Abstract and Applied Analysis 1 Discrete Dynamics in Nature and Society 1 Communications in Nonlinear Science and Numerical Simulation 1 Nonlinear Analysis. Real World Applications 1 Iranian Journal of Science and Technology. Transaction A: Science 1 SIAM Journal on Applied Dynamical Systems 1 Boundary Value Problems 1 Applications and Applied Mathematics 1 Mathematical Modelling of Natural Phenomena 1 Asian-European Journal of Mathematics 1 International Journal of Differential Equations 1 S$$\vec{\text{e}}$$MA Journal 1 Journal of Theoretical Biology 1 Journal of Mathematical Modeling 1 International Journal of Applied and Computational Mathematics
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Cited in 23 Fields
46 Ordinary differential equations (34-XX) 33 Real functions (26-XX) 25 Partial differential equations (35-XX) 22 Biology and other natural sciences (92-XX) 19 Numerical analysis (65-XX) 14 Dynamical systems and ergodic theory (37-XX) 11 Special functions (33-XX) 8 Operator theory (47-XX) 6 Calculus of variations and optimal control; optimization (49-XX) 5 Integral equations (45-XX) 4 Harmonic analysis on Euclidean spaces (42-XX) 4 Integral transforms, operational calculus (44-XX) 4 Statistical mechanics, structure of matter (82-XX) 3 Probability theory and stochastic processes (60-XX) 3 Fluid mechanics (76-XX) 3 Geophysics (86-XX) 2 Measure and integration (28-XX) 2 Difference and functional equations (39-XX) 2 Classical thermodynamics, heat transfer (80-XX) 2 Systems theory; control (93-XX) 1 Functional analysis (46-XX) 1 Relativity and gravitational theory (83-XX) 1 Game theory, economics, finance, and other social and behavioral sciences (91-XX)
Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2021-06-13T09:12:14 |
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|
https://candycrush.fandom.com/wiki/Moon_Scale
|
## FANDOM
18,037 Pages
Removed content This page contains information about content that was previously in the game but now got removed.
The moon scale was an element in Dreamworld levels, where the main mascot of Dreamworld, Odus, an owl, balanced on in the levels.
On the moon scale, on either side, there are two different candy colours. Players must get them in equal quantities, or else Odus will fall and the level will be failed.
Odus will only give a full update at the end of each move. So if Odus takes 10 candies to fall and you destroyed 12 of Colour A but then felt lucky to destroy 3 of Colour B, Odus will not fall. The calculation of the status is Abs $(Colour A - Colour B)$at the end of a move, or $|Colour A - Colour B|$.
There are exceptions to this rule:
• a) when your last move fulfils the clearing condition (including making the last move for Moves levels).
• b) when it is the move before moon struck takes effect.
• c) when the last move remaining is used. Even though the player fails the level, in this case, the moon scale does not tip over.
The moon meter is filled after a certain number of moves made by the player, which varies per level. Note that shuffles do not count, however. On the web version, it used to hurt players because a shuffle wasted a move (no longer the case with the release of Sour Salon).
When the moon meter is full, moon struck begins. This removes one or two candy colours appearing on the moon scale, meaning a player has fewer colours on the board to deal with. This effect sustains for a certain amount of moves that vary per level. At this moment, the board blinks and you are allowed some moves which decrease the moon meter until the moon scale is back to navy blue and the moon meter down to zero. After those moves, the board returns to normal, and the moon scale will change the two candies you have to balance.
## StabilityEdit
Balancing a Moon Scale is certainly easier said than done on most levels. The reason being that a player almost always must destroy candies in sets of three or more. Colour bombs are the most dangerous special candies here because they can take down a lot of candies and cause all kinds of cascades.
Depending on the level, a moon scale can handle a certain amount of candies before Odus falls. The moon scale seems to be less stable in some levels than in others. For example, level 203 only takes a mere imbalance of 5 candies for Odus to fall while level 368 takes a whopping 18 candies of imbalance to make Odus fall.
Level 202 used to have the most unstable moon scale in the game along with level 203 before the update, but it was nerfed, and now has a normal moon scale but with a shorter Moon Struck.
The moon scale had been known to have the following levels of Odus's stability (worries-panics-falls):
• Unstable: 2-4-5, 3-5-6, 3-5-7, 3-6-8, 4-7-9.
• Normal: 4-8-10, 5-9-11, 5-9-12.
• Stable: 5-10-13, 6-11-14, 6-12-15, 7-13-16, 7-14-17, 7-14-18.
The Moon Scale behaved differently on the web version and mobile version:
• On the web version, the moon scale only showed change after all cascades have ended. Odus will also make some noise when he begins to worry.
• On the mobile version, any change affecting the moon scale would be shown immediately. It was easier to tell whether Odus was going to fall before your next move.
## TriviaEdit
• When a player loses the level and pays to play 5 more moves, the moon scale truly goes back to neutral even if the owl would've fallen on that move.
• The moon scale is more responsive on mobile devices than web versions.
• Levels 230, 469, 470, 490, 493, and 546 require fewer moves to simply fill up the moon scale than the duration of moon struck.
• The levels with the least number of moves required to simply fill up the moon meter are levels pre-buffed 434, 439, 486, 494, 505, 506, 507, 508, 510, 555, and 567 at 3 moves each. The level with the most number of moves required to simply fill up the moon meter is Level 146 at 36 moves.
• The two candies that appear on the moon scale after an empty meter will always be two of the four colours left on the board before Odus returns. This can make it more dangerous to make cascades as there are so many candies of that colour.
• Seemingly, Coconut Wheels and Jelly Fish that activate will help rebalance Odus if he fell. In other words, if you made a move that would supposedly make Odus fall, he would fall. If you make a move that he rebalances, it will save him.
• The moon scale does not truly come into effect until the first move of the level is made. So if there are levels that drop candies such as level 10, the moon scale is not affected. Ironically, on the web version, Odus is truly flying before all the candies stop. On mobile devices, the two colours appear on the moon scale only after all the candies settle.
• On the mobile version (as of 1.50), it's possible to make one "quick move" right after the moon struck ended and before Odus settles on the moon scale again. This move will not affect the moon scale, and it will cause the next Moon Struck to delay for one turn. This can be performed for every subsequent Moon Struck, causing the activation to be further delayed. This was fixed in 1.55.1.
• Any candy that is destroyed whether after the first move is made and by a non-move (i.e. Lollipop Hammer), it will affect the moon scale.
• This is also among the most hated elements because a tip too far results in a level failed.
• The moon scale patterns seem to follow a 2:4:5 ratio (worry : panic : fall), with decimals rounded to the nearest integer. The "fall" value lies between 5 and 18, except 17.
• A probable reason is that, having a 17-scale (6.8 : 13.6 : 17 -> 7 : 14 : 17) is too similar with 18-scale (7.2 : 14.4 : 18 -> 7 : 14 : 18).
• If the player fails a level because of Odus falling off the moon scale, the failure reason will show as "Odus fell off the moon!" on the web version. However, in mobile, failing a level because Odus fell off the moon scale would show the reason as "You did not (clear all the jelly/bring down all ingredients/finish all the orders/reach the target score/reach the target score in time)".
## Start a Discussion Discussions about Moon Scale
• #### What do you say after Odus fell down?
18 messages
• rip dreamworld
• FU Odus. F dreamworld. Dreamworld is a stupid part of the product that is not tested by King. The scale is oversensitive on alot of levels. Th...
• #### Dreamworld
2 messages
• Wat is dat ik begrijp het nog niet
• 3
Community content is available under CC-BY-SA unless otherwise noted.
| 2020-09-25T07:45:32 |
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http://www.hmrc.gov.uk/manuals/ihtmanual/IHTM08121.htm
|
# IHTM08121 - Caseworking: penalties - when not to refer to Compliance Group
Where the de minimis limits for penalties are exceeded there are still some circumstances where a reference to Compliance Group is unnecessary. (This text has been withheld because of exemptions in the Freedom of Information Act 2000)
(This text has been withheld because of exemptions in the Freedom of Information Act 2000) (This text has been withheld because of exemptions in the Freedom of Information Act 2000) (This text has been withheld because of exemptions in the Freedom of Information Act 2000) (This text has been withheld because of exemptions in the Freedom of Information Act 2000) (This text has been withheld because of exemptions in the Freedom of Information Act 2000) (This text has been withheld because of exemptions in the Freedom of Information Act 2000) (This text has been withheld because of exemptions in the Freedom of Information Act 2000) (This text has been withheld because of exemptions in the Freedom of Information Act 2000) (This text has been withheld because of exemptions in the Freedom of Information Act 2000) (This text has been withheld because of exemptions in the Freedom of Information Act 2000) (This text has been withheld because of exemptions in the Freedom of Information Act 2000)
(This text has been withheld because of exemptions in the Freedom of Information Act 2000)
| 2013-06-19T22:18:39 |
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https://ftp.mcs.anl.gov/pub/fathom/moab-docs/classMBMesquite_1_1TSizeNB1.html
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MOAB: Mesh Oriented datABase (version 5.3.1)
MBMesquite::TSizeNB1 Class Reference
#include <TSizeNB1.hpp>
Inheritance diagram for MBMesquite::TSizeNB1:
Collaboration diagram for MBMesquite::TSizeNB1:
Public Member Functions
virtual MESQUITE_EXPORT ~TSizeNB1 ()
virtual MESQUITE_EXPORT std::string get_name () const
virtual MESQUITE_EXPORT bool evaluate (const MsqMatrix< 2, 2 > &T, double &result, MsqError &err)
Evaluate $$\mu(T)$$.
virtual MESQUITE_EXPORT bool evaluate_with_grad (const MsqMatrix< 2, 2 > &T, double &result, MsqMatrix< 2, 2 > &deriv_wrt_T, MsqError &err)
Gradient of $$\mu(T)$$ with respect to components of T.
virtual MESQUITE_EXPORT bool evaluate_with_hess (const MsqMatrix< 2, 2 > &T, double &result, MsqMatrix< 2, 2 > &deriv_wrt_T, MsqMatrix< 2, 2 > second_wrt_T[3], MsqError &err)
Hessian of $$\mu(T)$$ with respect to components of T.
virtual MESQUITE_EXPORT bool evaluate (const MsqMatrix< 3, 3 > &T, double &result, MsqError &err)
Evaluate $$\mu(T)$$.
virtual MESQUITE_EXPORT bool evaluate_with_grad (const MsqMatrix< 3, 3 > &T, double &result, MsqMatrix< 3, 3 > &deriv_wrt_T, MsqError &err)
Gradient of $$\mu(T)$$ with respect to components of T.
virtual MESQUITE_EXPORT bool evaluate_with_hess (const MsqMatrix< 3, 3 > &T, double &result, MsqMatrix< 3, 3 > &deriv_wrt_T, MsqMatrix< 3, 3 > second_wrt_T[6], MsqError &err)
Hessian of $$\mu(T)$$ with respect to components of T.
Detailed Description
(det(T)-1)^2
Definition at line 42 of file TSizeNB1.hpp.
Constructor & Destructor Documentation
MBMesquite::TSizeNB1::~TSizeNB1 ( ) [virtual]
Definition at line 46 of file TSizeNB1.cpp.
{}
Member Function Documentation
virtual MESQUITE_EXPORT bool MBMesquite::TSizeNB1::evaluate ( const MsqMatrix< 2, 2 > & T, double & result, MsqError & err ) [virtual]
Evaluate $$\mu(T)$$.
Parameters:
T 2x2 relative measure matrix (typically A W^-1) result Output: value of function
Returns:
false if function cannot be evaluated for given T (e.g. division by zero, etc.), true otherwise.
Reimplemented from MBMesquite::TMetric.
virtual MESQUITE_EXPORT bool MBMesquite::TSizeNB1::evaluate ( const MsqMatrix< 3, 3 > & T, double & result, MsqError & err ) [virtual]
Evaluate $$\mu(T)$$.
Parameters:
T 3x3 relative measure matrix (typically A W^-1) result Output: value of function
Returns:
false if function cannot be evaluated for given T (e.g. division by zero, etc.), true otherwise.
Reimplemented from MBMesquite::TMetric.
virtual MESQUITE_EXPORT bool MBMesquite::TSizeNB1::evaluate_with_grad ( const MsqMatrix< 2, 2 > & T, double & result, MsqMatrix< 2, 2 > & deriv_wrt_T, MsqError & err ) [virtual]
Gradient of $$\mu(T)$$ with respect to components of T.
Parameters:
T 2x2 relative measure matrix (typically A W^-1) result Output: value of function deriv_wrt_T Output: partial deriviatve of $$\mu$$ wrt each term of T, evaluated at passed T. $\left[\begin{array}{cc} \frac{\partial\mu}{\partial T_{0,0}} & \frac{\partial\mu}{\partial T_{0,1}} \\ \frac{\partial\mu}{\partial T_{1,0}} & \frac{\partial\mu}{\partial T_{1,1}} \\ \end{array}\right]$
Returns:
false if function cannot be evaluated for given T (e.g. division by zero, etc.), true otherwise.
Reimplemented from MBMesquite::TMetric.
virtual MESQUITE_EXPORT bool MBMesquite::TSizeNB1::evaluate_with_grad ( const MsqMatrix< 3, 3 > & T, double & result, MsqMatrix< 3, 3 > & deriv_wrt_T, MsqError & err ) [virtual]
Gradient of $$\mu(T)$$ with respect to components of T.
Parameters:
T 3x3 relative measure matrix (typically A W^-1) result Output: value of function deriv_wrt_T Output: partial deriviatve of $$\mu$$ wrt each term of T, evaluated at passed T. $\left[\begin{array}{ccc} \frac{\partial\mu}{\partial T_{0,0}} & \frac{\partial\mu}{\partial T_{0,1}} & \frac{\partial\mu}{\partial T_{0,2}} \\ \frac{\partial\mu}{\partial T_{1,0}} & \frac{\partial\mu}{\partial T_{1,1}} & \frac{\partial\mu}{\partial T_{1,2}} \\ \frac{\partial\mu}{\partial T_{2,0}} & \frac{\partial\mu}{\partial T_{2,1}} & \frac{\partial\mu}{\partial T_{2,2}} \end{array}\right]$
Returns:
false if function cannot be evaluated for given T (e.g. division by zero, etc.), true otherwise.
Reimplemented from MBMesquite::TMetric.
virtual MESQUITE_EXPORT bool MBMesquite::TSizeNB1::evaluate_with_hess ( const MsqMatrix< 2, 2 > & T, double & result, MsqMatrix< 2, 2 > & deriv_wrt_T, MsqMatrix< 2, 2 > second_wrt_T[3], MsqError & err ) [virtual]
Hessian of $$\mu(T)$$ with respect to components of T.
Parameters:
T 3x3 relative measure matrix (typically A W^-1) result Output: value of function deriv_wrt_T Output: partial deriviatve of $$\mu$$ wrt each term of T, evaluated at passed T. second_wrt_T Output: 9x9 matrix of second partial deriviatve of $$\mu$$ wrt each term of T, in row-major order. The symmetric matrix is decomposed into 3x3 blocks and only the upper diagonal blocks, in row-major order, are returned. $\left[\begin{array}{cc|cc} \frac{\partial^{2}\mu}{\partial T_{0,0}^2} & \frac{\partial^{2}\mu}{\partial T_{0,0}\partial A_{0,1}} & \frac{\partial^{2}\mu}{\partial T_{0,0}\partial A_{1,0}} & \frac{\partial^{2}\mu}{\partial T_{0,0}\partial A_{1,1}} \\ \frac{\partial^{2}\mu}{\partial T_{0,0}\partial A_{0,1}} & \frac{\partial^{2}\mu}{\partial T_{0,1}^2} & \frac{\partial^{2}\mu}{\partial T_{0,1}\partial A_{1,0}} & \frac{\partial^{2}\mu}{\partial T_{0,1}\partial A_{1,1}} \\ \hline & & \frac{\partial^{2}\mu}{\partial T_{1,0}^2} & \frac{\partial^{2}\mu}{\partial T_{1,0}\partial A_{1,1}} \\ & & \frac{\partial^{2}\mu}{\partial T_{1,0}\partial A_{1,1}} & \frac{\partial^{2}\mu}{\partial T_{1,1}^2} \\ \end{array}\right]$
Returns:
false if function cannot be evaluated for given T (e.g. division by zero, etc.), true otherwise.
Reimplemented from MBMesquite::TMetric.
virtual MESQUITE_EXPORT bool MBMesquite::TSizeNB1::evaluate_with_hess ( const MsqMatrix< 3, 3 > & T, double & result, MsqMatrix< 3, 3 > & deriv_wrt_T, MsqMatrix< 3, 3 > second_wrt_T[6], MsqError & err ) [virtual]
Hessian of $$\mu(T)$$ with respect to components of T.
Parameters:
T 3x3 relative measure matrix (typically A W^-1) result Output: value of function deriv_wrt_T Output: partial deriviatve of $$\mu$$ wrt each term of T, evaluated at passed T. second_wrt_T Output: 9x9 matrix of second partial deriviatve of $$\mu$$ wrt each term of T, in row-major order. The symmetric matrix is decomposed into 3x3 blocks and only the upper diagonal blocks, in row-major order, are returned. $\left[\begin{array}{ccc|ccc|ccc} \frac{\partial^{2}\mu}{\partial T_{0,0}^2} & \frac{\partial^{2}\mu}{\partial T_{0,0}\partial T_{0,1}} & \frac{\partial^{2}\mu}{\partial T_{0,0}\partial T_{0,2}} & \frac{\partial^{2}\mu}{\partial T_{0,0}\partial T_{1,0}} & \frac{\partial^{2}\mu}{\partial T_{0,0}\partial T_{1,1}} & \frac{\partial^{2}\mu}{\partial T_{0,0}\partial T_{1,2}} & \frac{\partial^{2}\mu}{\partial T_{0,0}\partial T_{2,0}} & \frac{\partial^{2}\mu}{\partial T_{0,0}\partial T_{2,1}} & \frac{\partial^{2}\mu}{\partial T_{0,0}\partial T_{2,2}} \\ \frac{\partial^{2}\mu}{\partial T_{0,0}\partial T_{0,1}} & \frac{\partial^{2}\mu}{\partial T_{0,1}^2} & \frac{\partial^{2}\mu}{\partial T_{0,1}\partial T_{0,2}} & \frac{\partial^{2}\mu}{\partial T_{0,1}\partial T_{1,0}} & \frac{\partial^{2}\mu}{\partial T_{0,1}\partial T_{1,1}} & \frac{\partial^{2}\mu}{\partial T_{0,1}\partial T_{1,2}} & \frac{\partial^{2}\mu}{\partial T_{0,1}\partial T_{2,0}} & \frac{\partial^{2}\mu}{\partial T_{0,1}\partial T_{2,1}} & \frac{\partial^{2}\mu}{\partial T_{0,1}\partial T_{2,2}} \\ \frac{\partial^{2}\mu}{\partial T_{0,0}\partial T_{0,2}} & \frac{\partial^{2}\mu}{\partial T_{0,1}\partial T_{0,2}} & \frac{\partial^{2}\mu}{\partial T_{0,2}^2} & \frac{\partial^{2}\mu}{\partial T_{0,2}\partial T_{1,0}} & \frac{\partial^{2}\mu}{\partial T_{0,2}\partial T_{1,1}} & \frac{\partial^{2}\mu}{\partial T_{0,2}\partial T_{1,2}} & \frac{\partial^{2}\mu}{\partial T_{0,2}\partial T_{2,0}} & \frac{\partial^{2}\mu}{\partial T_{0,2}\partial T_{2,1}} & \frac{\partial^{2}\mu}{\partial T_{0,2}\partial T_{2,2}} \\ \hline & & & \frac{\partial^{2}\mu}{\partial T_{1,0}^2} & \frac{\partial^{2}\mu}{\partial T_{1,0}\partial T_{1,1}} & \frac{\partial^{2}\mu}{\partial T_{1,0}\partial T_{1,2}} & \frac{\partial^{2}\mu}{\partial T_{1,0}\partial T_{2,0}} & \frac{\partial^{2}\mu}{\partial T_{1,0}\partial T_{2,1}} & \frac{\partial^{2}\mu}{\partial T_{1,0}\partial T_{2,2}} \\ & & & \frac{\partial^{2}\mu}{\partial T_{1,0}\partial T_{1,1}} & \frac{\partial^{2}\mu}{\partial T_{1,1}^2} & \frac{\partial^{2}\mu}{\partial T_{1,1}\partial T_{1,2}} & \frac{\partial^{2}\mu}{\partial T_{1,1}\partial T_{2,0}} & \frac{\partial^{2}\mu}{\partial T_{1,1}\partial T_{2,1}} & \frac{\partial^{2}\mu}{\partial T_{1,1}\partial T_{2,2}} \\ & & & \frac{\partial^{2}\mu}{\partial T_{1,0}\partial T_{1,2}} & \frac{\partial^{2}\mu}{\partial T_{1,1}\partial T_{1,2}} & \frac{\partial^{2}\mu}{\partial T_{1,2}^2} & \frac{\partial^{2}\mu}{\partial T_{1,2}\partial T_{2,0}} & \frac{\partial^{2}\mu}{\partial T_{1,2}\partial T_{2,1}} & \frac{\partial^{2}\mu}{\partial T_{1,2}\partial T_{2,2}} \\ \hline & & & & & & \frac{\partial^{2}\mu}{\partial T_{2,0}^2} & \frac{\partial^{2}\mu}{\partial T_{2,0}\partial T_{2,1}} & \frac{\partial^{2}\mu}{\partial T_{2,0}\partial T_{2,2}} \\ & & & & & & \frac{\partial^{2}\mu}{\partial T_{2,0}\partial T_{2,1}} & \frac{\partial^{2}\mu}{\partial T_{2,1}^2} & \frac{\partial^{2}\mu}{\partial T_{2,1}\partial T_{2,2}} \\ & & & & & & \frac{\partial^{2}\mu}{\partial T_{2,0}\partial T_{2,2}} & \frac{\partial^{2}\mu}{\partial T_{2,1}\partial T_{2,2}} & \frac{\partial^{2}\mu}{\partial T_{2,2}^2} \\ \end{array}\right]$
Returns:
false if function cannot be evaluated for given T (e.g. division by zero, etc.), true otherwise.
Reimplemented from MBMesquite::TMetric.
std::string MBMesquite::TSizeNB1::get_name ( ) const [virtual]
Reimplemented from MBMesquite::TMetricNonBarrier.
Definition at line 41 of file TSizeNB1.cpp.
{
return "TSizeNB1";
}
List of all members.
The documentation for this class was generated from the following files:
| 2021-12-02T13:08:23 |
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https://par.nsf.gov/biblio/10223272
|
Nonlinear magnetoelectric effects in Al-substituted strontium hexaferrite
Abstract
This report is on the observation and theory of electric fieldEinduced non-linear magnetoelectric (NLME) effects in single crystal platelets of ferrimagnetic M-type strontium aluminum hexagonal ferrite. Using microwave measurement techniques, it was found that a DC electric field along the hexagonal c-axis results in significant changes in the saturation magnetization and uniaxial magneto-crystalline anisotropy field and these changes are proportional to the square of the applied static electric field. The NLME effects were present with or without an external bias magnetic field. TheE-induced variation in magnetic order parameters is attributed to weakening of magnetic exchange and spin–orbit interactions since conduction electrons in the ferrite are effectively excluded from both interactions while being in transit from one Fe ion to another. We present a phenomenological theory which considers magneto-bielectric effects characterized by a quadratic term in electric fieldEin the free energy density. The coefficients for the NLME coupling terms have been calculated from experimental data and they do show variations with the Al substitution level and the largest rates of change of the saturation magnetization and anisotropy constant change with the applied power were observed for x = 0.4. It was also clear from the study that strength of the NLME effect more »
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NSF-PAR ID:
10223272
Journal Name:
Scientific Reports
Volume:
11
Issue:
1
ISSN:
2045-2322
Publisher:
Nature Publishing Group
National Science Foundation
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1. Abstract
This report is on studies directed at the nature of magneto-electric (ME) coupling by ferromagnetic resonance (FMR) under an electric field in a coaxial nanofiber of nickel ferrite (NFO) and lead zirconate titanate (PZT). Fibers with ferrite cores and PZT shells were prepared by electrospinning. The core–shell structure of annealed fibers was confirmed by electron- and scanning probe microscopy. For studies on converse ME effects, i.e., the magnetic response of the fibers to an applied electric field, FMR measurements were done on a single fiber with a near-field scanning microwave microscope (NSMM) at 5–10 GHz by obtaining profiles of bothmore »
2. Abstract
Nonlinear photocurrent in time-reversal invariant noncentrosymmetric systems such as ferroelectric semimetals sparked tremendous interest of utilizing nonlinear optics to characterize condensed matter with exotic phases. Here we provide a microscopic theory of two types of second-order nonlinear direct photocurrents, magnetic shift photocurrent (MSC) and magnetic injection photocurrent (MIC), as the counterparts of normal shift current (NSC) and normal injection current (NIC) in time-reversal symmetry and inversion symmetry broken systems. We show that MSC is mainly governed by shift vector and interband Berry curvature, and MIC is dominated by absorption strength and asymmetry of the group velocity difference at time-reversedmore »
3. SUMMARY Anisotropy of remanent magnetization and magnetic susceptibility are highly sensitive and important indicators of geological processes which are largely controlled by mineralogical parameters of the ferrimagnetic fraction in rocks. To provide new physical insight into the complex interaction between magnetization structure, shape, and crystallographic relations, we here analyse ‘slice-and-view’ focused-ion-beam (FIB) nano-tomography data with micromagnetic modelling and single crystal hysteresis measurements. The data sets consist of 68 magnetite inclusions in orthopyroxene (Mg60) and 234 magnetite inclusions in plagioclase (An63) were obtained on mineral separates from the Rustenburg Layered Suite of the Bushveld Intrusive Complex, South Africa. Electron backscatter diffractionmore »
4. Abstract
Although the frustrated (zigzag) spin chain is the Drosophila of frustrated magnetism, our understanding of a pair of coupled zigzag chains (frustrated spin ladder) in a magnetic field is still lacking. We address this problem through nuclear magnetic resonance (NMR) experiments on BiCu$$_2$$${}_{2}$PO$$_6$$${}_{6}$in magnetic fields up to 45 T, revealing a field-induced spiral magnetic structure. Conjointly, we present advanced numerical calculations showing that even a moderate rung coupling dramatically simplifies the phase diagram below half-saturation magnetization by stabilizing a field-induced chiral phase. Surprisingly for a one-dimensional model, this phase and its response to Dzyaloshinskii-Moriya (DM) interactions adhere to classical expectations.more »
5. Abstract
The angular dependence of the microwave-driven spin rectification (SR) effect in single crystalline Co0.5Fe0.5alloy film is systematically investigated. Due to the strong current-orientation dependent anisotropic magnetoresistance (AMR), the SR effects in CoFe film strongly deviate from the ordinary sin 2φMcosφMrelation withφMdefined as the magnetization angle away from the current. A giant Gilbert damping anisotropy in the CoFe film with a maximum–minimum ratio of 520% is observed, which can impose a strong anisotropy onto magnetic susceptibility. The observed unusual angular dependence can be well explained by the theory including current-orientation dependent AMR and anisotropic magnetic susceptibility. Our work also suggestsmore »
| 2022-06-28T19:17:04 |
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http://ocw.usu.edu/Electrical_and_Computer_Engineering/Stochastic_Processes/lecture9_1.htm
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# Linear Minimum Mean-Square Error Filtering
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Background :: Filtering
## Background
Recall that for random variable and with finite variance, the MSE is minimized by . That is, the best estimate of using a measured value of is to find the conditional average of . One aspect of this estimate is that:
The error is orthogonal to the data.
More precisely, the error is orthogonal to and to every function of :
for all measurable functions . We will assume that .
We want to show that minimizes if and only if (orthogonality), for all measurable such that .
Conversely, suppose for some , . Consider the estimate
where
Then
Suppose now we are given two random processes and that are statistically related (that is, not independent). Suppose, to begin, that . Suppose we observe over the interval , and based on the information gained we want to estimate for some fixed as a function of . That is, we form
for some functional mapping the function to real numbers.
If : We say that the operation of the function is smoothing .
If : We way that the operation of the function is filtering .
If : We way that the operation of the function is prediction .
The error in the estimate is . The mean-squared error is .
Fact (built on our previous intuition): The MSE is minimized by the conditional expectation
Furthermore, the orthogonality principle applies: is orthogonal to every function of .
While we know the theoretical result, it is difficult in general to compute the desired conditional expectation.
Note that may include infinite sequences, so we assume mean-square limits. The set contains mean-square derivatives, mean-square integrals, and other linear transformations of . (The set is the Hilbert space generated by the linear span of .)
Let's now solve
()
A couple important properties:
• If then solves (*) if and only if for all . That is, the error is orthogonal to all elements of .
• for all if and only if and for all .
This is a restatement of orthogonality, but for a restricted space.
Suppose we further restrict to be of the form
That is, is the output of a linear filter driven by . Note that . By property 2, we must have (1)
so that
and (2):
for . That is,
This gives us two equations in the unknowns and . We can eliminate :
or
or
The optimal is that which solves this integral equation.
Since we are dealing with covariances, the means have been eliminated. It is frequently assumed that and have zero means. In this case, the covariances are equal to the correlations, and we can write
This equation is called the Wiener-Hopf equation.
An integral equation of this form is called a Fredholm equation . The theory on the existence of solutions Fredholm integral equations is well-known. In practice, solutions are usually numerical.
The solution is sometimes called a Wiener filter .
The filter in this case is called a Non-Causal Wiener Filter .
It can be shown that the residual error for the noncausal Wiener filter is
This can be seen as follows:
By orthogonality, the last term is 0, which implies that . We thus obtain
The MMSE is sometimes written as
where
Copyright 2008, Todd Moon. Cite/attribute Resource . admin. (2006, June 07). Linear Minimum Mean-Square Error Filtering. Retrieved January 07, 2011, from Free Online Course Materials — USU OpenCourseWare Web site: http://ocw.usu.edu/Electrical_and_Computer_Engineering/Stochastic_Processes/lecture9_1.htm. This work is licensed under a Creative Commons License
| 2017-12-14T22:36:53 |
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http://dergipark.gov.tr/baebd/page/4396
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Plagiarism Policy
In Western Anatolia Educational Science Journal, authors are responsible from the similarity with other publications in their articles. For this reason, the BAEBD requires a similarity rate report from the author in the preliminary control phase.
| 2019-04-21T04:24:11 |
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https://par.nsf.gov/biblio/10337077-supercalifragilisticexpialidocious-why-using-theright-readability-formula-inchildrens-web-search-matters
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This content will become publicly available on January 1, 2023
Supercalifragilisticexpialidocious: Why Using the “Right” Readability Formula in Children’s Web Search Matters
Readability is a core component of information retrieval (IR) tools as the complexity of a resource directly affects its relevance: a resource is only of use if the user can comprehend it. Even so, the link between readability and IR is often overlooked. As a step towards advancing knowledge on the influence of readability on IR, we focus on Web search for children. We explore how traditional formulas–which are simple, efficient, and portable–fare when applied to estimating the readability of Web resources for children written in English. We then present a formula well-suited for readability estimation of child-friendly Web resources. Lastly, we empirically show that readability can sway children’s information access. Outcomes from this work reveal that: (i) for Web resources targeting children, a simple formula suffices as long as it considers contemporary terminology and audience requirements, and (ii) instead of turning to Flesch-Kincaid–a popular formula–the use of the “right” formula can shape Web search tools to best serve children. The work we present herein builds on three pillars: Audience, Application, and Expertise. It serves as a blueprint to place readability estimation methods that best apply to and inform IR applications serving varied audiences.
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NSF-PAR ID:
10337077
Journal Name:
44th European Conference on Information Retrieval (ECIR)
Page Range or eLocation-ID:
3-18
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National Science Foundation
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1. Bicycle design has not changed for a long time, as they are well-crafted for those that possess the skills to ride, i.e., adults. Those learning to ride, however, often need additional support in the form of training wheels. Searching for information on the Web is much like riding a bicycle, where modern search engines (the bicycle) are optimized for general use and adult users, but lack the functionality to support non-traditional audiences and environments. In this thesis, we introduce a set of training wheels in the form of a learning to rank model as augmentation for standard search engines tomore »
2. Given the more widespread nature of natural language interfaces, it is increasingly important to understand who are accessing those interfaces, and how those interfaces are being used. In this paper, we explore spellchecking in the context of web search with children as the target audience. In particular, via a literature review we show that, while widely used, popular search tools are ill-designed for children. We then use spellcheckers as a case study to highlight the need for an interdisciplinary approach that brings together natural language processing, education, human-computer interaction to address a known information retrieval problem: query misspelling. We concludemore »
3. Children use popular web search tools, which are generally designed for adult users. Because children have different developmental needs than adults, these tools may not always adequately support their search for information. Moreover, even though search tools offer support to help in query formulation, these too are aimed at adults and may hinder children rather than help them. This calls for the examination of existing technologies in this area, to better understand what remains to be done when it comes to facilitating query-formulation tasks for young users. In this paper, we investigate interaction elements of query formulation--including query suggestion algorithms--formore »
4. Abstract Precipitation measurements with high spatiotemporal resolution are a vital input for hydrometeorological and water resources studies; decision-making in disaster management; and weather, climate, and hydrological forecasting. Moreover, real-time precipitation estimation with high precision is pivotal for the monitoring and managing of catastrophic hydroclimate disasters such as flash floods, which frequently transpire after extreme rainfall. While algorithms that exclusively use satellite infrared data as input are attractive owing to their rich spatiotemporal resolution and near-instantaneous availability, their sole reliance on cloud-top brightness temperature (Tb) readings causes underestimates in wet regions and overestimates in dry regions—this is especially evident over themore »
5. The design of cyber-physical systems (CPSs) requires methods and tools that can efficiently reason about the interaction between discrete models, e.g., representing the behaviors of cyber'' components, and continuous models of physical processes. Boolean methods such as satisfiability (SAT) solving are successful in tackling large combinatorial search problems for the design and verification of hardware and software components. On the other hand, problems in control, communications, signal processing, and machine learning often rely on convex programming as a powerful solution engine. However, despite their strengths, neither approach would work in isolation for CPSs. In this paper, we present a newmore »
| 2022-08-07T16:31:37 |
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https://par.nsf.gov/biblio/10093274-uniqueness-stability-shock-reflection-diffraction-problem-potential-flow
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Uniqueness and Stability for the Shock Reflection-Diffraction Problem for Potential Flow
When a plane shock hits a two-dimensional wedge head on, it experiences a reflection-diffraction process, and then a self-similar reflected shock moves outward as the original shock moves forward in time. The experimental, computational, and asymptotic analysis has indicated that various patterns occur, including regular reflection and Mach reflection. The von Neumann's conjectures on the transition from regular to Mach reflection involve the existence, uniqueness, and stability of regular shock reflection-diffraction configurations, generated by concave cornered wedges for compressible flow. In this paper, we discuss some recent developments in the study of the von Neumann's conjectures. More specifically, we discuss the uniqueness and stability of regular shock reflection-diffraction configurations governed by the potential flow equation in an appropriate class of solutions. We first show that the transonic shocks in the global solutions obtained in Chen-Feldman [19] are convex. Then we establish the uniqueness of global shock reflection-diffraction configurations with convex transonic shocks for any wedge angle larger than the detachment angle or the critical angle. Moreover, the solution under consideration is stable with respect to the wedge angle. Our approach also provides an alternative way of proving the existence of the admissible solutions established first in [19].
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NSF-PAR ID:
10093274
Journal Name:
Proceedings of the XVII international conference on hyperbolic problems: Theory, numerics, applications
National Science Foundation
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1. We are concerned with free boundary problems arising from the analysis of multidimensional transonic shock waves for the Euler equations in compressible fluid dynamics. In this expository paper, we survey some recent developments in the analysis of multidimensional transonic shock waves and corresponding free boundary problems for the compressible Euler equations and related nonlinear partial differential equations (PDEs) of mixed type. The nonlinear PDEs under our analysis include the steady Euler equations for potential flow, the steady full Euler equations, the unsteady Euler equations for potential flow, and related nonlinear PDEs of mixed elliptic–hyperbolic type. The transonic shock problems include the problem of steady transonic flow past solid wedges, the von Neumann problem for shock reflection–diffraction, and the Prandtl–Meyer problem for unsteady supersonic flow onto solid wedges. We first show how these longstanding multidimensional transonic shock problems can be formulated as free boundary problems for the compressible Euler equations and related nonlinear PDEs of mixed type. Then we present an effective nonlinear method and related ideas and techniques to solve these free boundary problems. The method, ideas, and techniques should be useful to analyze other longstanding and newly emerging free boundary problems for nonlinear PDEs.
2. We are concerned with the suitability of the main models of compressible fluid dynamics for the Lighthill problem for shock diffraction by a convex corned wedge, by studying the regularity of solutions of the problem, which can be formulated as a free boundary problem. In this paper, we prove that there is no regular solution that is subsonic up to the wedge corner for potential flow. This indicates that, if the solution is subsonic at the wedge corner, at least a characteristic discontinuity (vortex sheet or entropy wave) is expected to be generated, which is consistent with the experimental and computational results. Therefore, the potential flow equation is not suitable for the Lighthill problem so that the compressible Euler system must be considered. In order to achieve the nonexistence result, a weak maximum principle for the solution is established, and several other mathematical techniques are developed. The methods and techniques developed here are also useful to the other problems with similar difficulties.
3. Abstract We present the first Faraday rotation measure (RM) grid study of an individual low-mass cluster—the Fornax cluster—which is presently undergoing a series of mergers. Exploiting commissioning data for the POlarisation Sky Survey of the Universe’s Magnetism (POSSUM) covering a ${\sim}34$ square degree sky area using the Australian Square Kilometre Array Pathfinder (ASKAP), we achieve an RM grid density of ${\sim}25$ RMs per square degree from a 280-MHz band centred at 887 MHz, which is similar to expectations for forthcoming GHz-frequency ${\sim}3\pi$ -steradian sky surveys. These data allow us to probe the extended magnetoionic structure of the cluster and its surroundings in unprecedented detail. We find that the scatter in the Faraday RM of confirmed background sources is increased by $16.8\pm2.4$ rad m −2 within 1 $^\circ$ (360 kpc) projected distance to the cluster centre, which is 2–4 times larger than the spatial extent of the presently detectable X-ray-emitting intracluster medium (ICM). The mass of the Faraday-active plasma is larger than that of the X-ray-emitting ICM and exists in a density regime that broadly matches expectations for moderately dense components of the Warm-Hot Intergalactic Medium. We argue that forthcoming RM grids from both targeted and survey observations may be amore »
4. In this paper, nonlinearity associated with intense ultrasound is studied by using the one-dimensional motion of nonlinear shock wave in an ideal fluid. In nonlinear acoustics, the wave speed of different segments of a waveform is different, which causes distortion in the waveform and can result in the formation of a shock (discontinuity). Acoustic pressure of high-intensity waves causes particles in the ideal fluid to vibrate forward and backward, and this disturbance is of relatively large magnitude due to high-intensities, which leads to nonlinearity in the waveform. In this research, this vibration of fluid due to the intense ultrasonic wave is modeled as a fluid pushed by one complete cycle of piston. In a piston cycle, as it moves forward, it causes fluid particles to compress, which may lead to the formation of a shock (discontinuity). Then as the piston retracts, a forward-moving rarefaction, a smooth fan zone of continuously changing pressure, density, and velocity is generated. When the piston stops at the end of the cycle, another shock is sent forward into the medium. The variation in wave speed over the entire waveform is calculated by solving a Riemann problem. This study examined the interaction of shocks with amore »
5. ABSTRACT Cosmic ray (CR)-modified shocks are a demanding test of numerical codes. We use them to test and validate the two-moment method for CR hydrodynamics, as well as characterize the realism of CR shock acceleration in two-fluid simulations which inevitably arises. Previously, numerical codes were unable to incorporate streaming in this demanding regime, and have never been compared against analytic solutions. First, we find a new analytic solution highly discrepant in acceleration efficiency from the standard solution. It arises from bi-directional streaming of CRs away from the subshock, similar to a Zeldovich spike in radiative shocks. Since fewer CRs diffuse back upstream, this favours a much lower acceleration efficiency, typically ${\lesssim}10{{\ \rm per\ cent}}$ (even for Mach number > 10) as opposed to ${\gtrsim}50{{\ \rm per\ cent}}$ found in previous analytic work. At Mach number ≳10, the new solution bifurcates into three branches, with efficient, intermediate, and inefficient CR acceleration. Our two-moment code accurately recovers these solutions across the entire parameter space probed, with no ad hoc closure relations. For generic initial conditions, the inefficient branch is robustly chosen by the code; the intermediate branch is unstable. The preferred branch is very weakly modified by CRs. At high Mach numbersmore »
| 2022-12-07T06:59:44 |
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https://zbmath.org/authors/?q=ai%3Awarga.jack
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## Warga, Jack
Compute Distance To:
Author ID: warga.jack Published as: Warga, J.; Warga, Jack External Links: MacTutor · MGP · Wikidata · dblp · IdRef
Documents Indexed: 69 Publications since 1950, including 1 Book Biographic References: 4 Publications Co-Authors: 5 Co-Authors with 6 Joint Publications 57 Co-Co-Authors
### Co-Authors
60 single-authored 3 Zhu, Qiji Jim 1 Hailey, W. C. 1 Neustadt, Lucien W. 1 Rosenblueth, Javier F. 1 Shapiro, Harold N.
all top 5
### Serials
13 SIAM Journal on Control and Optimization 8 Journal of Mathematical Analysis and Applications 6 SIAM Journal on Control 4 Journal of Differential Equations 4 Nonlinear Analysis. Theory, Methods & Applications 3 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 3 Journal of the Society for Industrial & Applied Mathematics 2 Journal of Optimization Theory and Applications 2 Michigan Mathematical Journal 2 Journal of the Society for Industrial & Applied Mathematics. Series A. Control 1 AIAA Journal 1 Communications on Pure and Applied Mathematics 1 Applied Mathematics and Optimization 1 IEEE Transactions on Automatic Control 1 Journal of Functional Analysis 1 Mathematics of Operations Research 1 Proceedings of the American Mathematical Society 1 Transactions of the American Mathematical Society 1 SIAM Review 1 SIAM Journal on Optimization 1 Bulletin of the American Mathematical Society 1 Journal of Mathematics and Physics 1 Set-Valued and Variational Analysis
all top 5
### Fields
41 Calculus of variations and optimal control; optimization (49-XX) 20 Systems theory; control (93-XX) 8 Operations research, mathematical programming (90-XX) 6 Functional analysis (46-XX) 5 Real functions (26-XX) 5 Ordinary differential equations (34-XX) 4 Global analysis, analysis on manifolds (58-XX) 3 General topology (54-XX) 3 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 2 Convex and discrete geometry (52-XX) 1 History and biography (01-XX) 1 Measure and integration (28-XX) 1 Operator theory (47-XX) 1 Numerical analysis (65-XX)
### Citations contained in zbMATH Open
57 Publications have been cited 1,056 times in 791 Documents Cited by Year
Optimal control of differential and functional equations. Zbl 0253.49001
Warga, J.
1972
Relaxed variational problems. Zbl 0102.31801
Warga, J.
1962
Fat homeomorphisms and unbounded derivate containers. Zbl 0476.26006
Warga, J.
1981
Functions of relaxed controls. Zbl 0234.49007
Warga, J.
1967
Variational problems with unbounded controls. Zbl 0201.47803
Warga, J.
1965
Derivate containers, inverse functions, and controllability. Zbl 0355.26004
Warga, Jack
1976
Controllability, extremality, and abnormality in nonsmooth optimal control. Zbl 0497.49033
Warga, J.
1983
Minimizing certain convex functions. Zbl 0128.05801
Warga, J.
1963
Necessary conditions for minimum in relaxed variational problems. Zbl 0102.31802
Warga, J.
1962
Optimization and controllability without differentiability assumptions. Zbl 0526.49026
Warga, J.
1983
Controllability and necessary conditions in unilateral problems without differentiability assumptions. Zbl 0325.49008
Warga, J.
1976
Necessary conditions without differentiability assumptions in optimal control. Zbl 0272.49005
Warga, J.
1975
Comments on the paper ’Optimal control of processes described by integral equations. I’ by V. R. Vinokurov. Zbl 0206.16503
1970
A second-order condition that strengthens Pontryagin’s maximum principle. Zbl 0346.49012
Warga, J.
1978
A second-order Lagrangian condition for restricted control problems. Zbl 0351.49003
Warga, J.
1978
Steepest descent with relaxed controls. Zbl 0356.49018
Warga, J.
1977
Necessary conditions without differentiability assumptions in unilateral control problems. Zbl 0323.49008
Warga, J.
1976
Minimizing variational curves restricted to a preassigned set. Zbl 0129.07403
Warga, J.
1964
Minimax problems and unilateral curves in the calculus of variations. Zbl 0137.08302
Warga, J.
1965
Normal control problems have no minimizing strictly original solutions. Zbl 0237.49004
Warga, J.
1971
A proper relaxation of shifted and delayed controls. Zbl 0776.49008
Warga, J.; Zhu, Q. J.
1992
The reduction of certain control problems to an ’ordinary differential’ type. Zbl 0155.14703
Warga, J.
1968
Control problems with functional restrictions. Zbl 0205.16701
Warga, J.
1970
Controllability of nondifferentiable hereditary processes. Zbl 0392.93010
Warga, J.
1978
Unilateral and minimax control problems defined by integral equations. Zbl 0205.16801
Warga, J.
1970
Controllability and a multiplier rule for nondifferentiable optimization problems. Zbl 0411.90075
Warga, J.
1978
An implicit function theorem without differentiability. Zbl 0348.26012
Warga, J.
1978
Higher order conditions with and without Lagrange multipliers. Zbl 0595.49017
Warga, J.
1986
Second order controllability and optimization with ordinary controls. Zbl 0559.49015
Warga, J.
1985
On a class of minimax problems in the calculus of variations. Zbl 0133.36401
Warga, J.
1965
Relaxed controls for functional equations. Zbl 0187.07904
Warga, J.
1970
Restricted minima of functions of controls. Zbl 0234.49008
Warga, J.
1967
Higher-order conditions for conical controllability. Zbl 0695.49020
Warga, J.
1988
An extension of the Kaskosz maximum principle. Zbl 0714.49025
Warga, J.
1990
On the representation of large integers as sums of primes. I. Zbl 0038.18602
Shapiro, Harold N.; Warga, Jack
1950
A proper relaxation of controls with variable shifts. Zbl 0901.49005
Warga, J.
1995
Unilateral variational problems with several inequalities. Zbl 0137.08401
Warga, J.
1965
Homeomorphisms and local $$C^ 1$$ approximations. Zbl 0652.46029
Warga, J.
1988
On a class of iterative procedures for solving normal systems of ordinary differential equations. Zbl 0050.12303
Warga, J.
1953
Optimal controls with pseudodelays. Zbl 0256.49010
Warga, J.
1974
Conflicting and minimax controls. Zbl 0186.49202
Warga, J.
1971
On a class of pursuit and evasion problems. Zbl 0206.45803
Warga, J.
1971
On the characterization of properly relaxed delayed controls. Zbl 0902.49006
Rosenblueth, J. F.; Warga, J.; Zhu, Q. J.
1997
On bounding, interior and covering functions. Zbl 0465.49026
Warga, J.
1981
Nonsmooth problems with conflicting controls. Zbl 0749.90098
Warga, J.
1991
A necessary and sufficient condition for a constrained minimum. Zbl 0770.90068
Warga, J.
1992
A uniqueness theorem and a counterexample for ordinary differential equations. Zbl 1120.34302
Warga, J.
2007
The equivalence of extremals in different representations of unbounded control problems. Zbl 0808.49008
Warga, J.; Zhu, Q. J.
1994
A hybrid relaxed-Lagrangian second order condition for minimum. Zbl 0414.49011
Warga, J.
1979
Iterative procedures for constrained and unilateral optimization problems. Zbl 0481.49021
Warga, J.
1982
A topological index condition for conical controllability. Zbl 0786.46007
Fang, G. X.; Warga, J.
1992
Functions with unstable images. I: Cracks of codimension 1. Zbl 0784.54014
Fang, G. X.; Warga, J.
1992
Functions with unstable images. II: Cracks of positive codimensions. Zbl 0784.54015
Fang, G. X.; Warga, J.
1992
A convergent procedure for solving the thermo-chemical equilibrium problem. Zbl 0199.22701
Warga, J.
1963
Global directional controllability. Zbl 0702.93008
Warga, J.
1989
Problems with delayed and shifted controls. Zbl 0967.49014
Warga, J.
2000
Relaxed derivatives and extremality conditions in optimal control. Zbl 1253.49015
Warga, Jack
2012
Relaxed derivatives and extremality conditions in optimal control. Zbl 1253.49015
Warga, Jack
2012
A uniqueness theorem and a counterexample for ordinary differential equations. Zbl 1120.34302
Warga, J.
2007
Problems with delayed and shifted controls. Zbl 0967.49014
Warga, J.
2000
On the characterization of properly relaxed delayed controls. Zbl 0902.49006
Rosenblueth, J. F.; Warga, J.; Zhu, Q. J.
1997
A proper relaxation of controls with variable shifts. Zbl 0901.49005
Warga, J.
1995
The equivalence of extremals in different representations of unbounded control problems. Zbl 0808.49008
Warga, J.; Zhu, Q. J.
1994
A proper relaxation of shifted and delayed controls. Zbl 0776.49008
Warga, J.; Zhu, Q. J.
1992
A necessary and sufficient condition for a constrained minimum. Zbl 0770.90068
Warga, J.
1992
A topological index condition for conical controllability. Zbl 0786.46007
Fang, G. X.; Warga, J.
1992
Functions with unstable images. I: Cracks of codimension 1. Zbl 0784.54014
Fang, G. X.; Warga, J.
1992
Functions with unstable images. II: Cracks of positive codimensions. Zbl 0784.54015
Fang, G. X.; Warga, J.
1992
Nonsmooth problems with conflicting controls. Zbl 0749.90098
Warga, J.
1991
An extension of the Kaskosz maximum principle. Zbl 0714.49025
Warga, J.
1990
Global directional controllability. Zbl 0702.93008
Warga, J.
1989
Higher-order conditions for conical controllability. Zbl 0695.49020
Warga, J.
1988
Homeomorphisms and local $$C^ 1$$ approximations. Zbl 0652.46029
Warga, J.
1988
Higher order conditions with and without Lagrange multipliers. Zbl 0595.49017
Warga, J.
1986
Second order controllability and optimization with ordinary controls. Zbl 0559.49015
Warga, J.
1985
Controllability, extremality, and abnormality in nonsmooth optimal control. Zbl 0497.49033
Warga, J.
1983
Optimization and controllability without differentiability assumptions. Zbl 0526.49026
Warga, J.
1983
Iterative procedures for constrained and unilateral optimization problems. Zbl 0481.49021
Warga, J.
1982
Fat homeomorphisms and unbounded derivate containers. Zbl 0476.26006
Warga, J.
1981
On bounding, interior and covering functions. Zbl 0465.49026
Warga, J.
1981
A hybrid relaxed-Lagrangian second order condition for minimum. Zbl 0414.49011
Warga, J.
1979
A second-order condition that strengthens Pontryagin’s maximum principle. Zbl 0346.49012
Warga, J.
1978
A second-order Lagrangian condition for restricted control problems. Zbl 0351.49003
Warga, J.
1978
Controllability of nondifferentiable hereditary processes. Zbl 0392.93010
Warga, J.
1978
Controllability and a multiplier rule for nondifferentiable optimization problems. Zbl 0411.90075
Warga, J.
1978
An implicit function theorem without differentiability. Zbl 0348.26012
Warga, J.
1978
Steepest descent with relaxed controls. Zbl 0356.49018
Warga, J.
1977
Derivate containers, inverse functions, and controllability. Zbl 0355.26004
Warga, Jack
1976
Controllability and necessary conditions in unilateral problems without differentiability assumptions. Zbl 0325.49008
Warga, J.
1976
Necessary conditions without differentiability assumptions in unilateral control problems. Zbl 0323.49008
Warga, J.
1976
Necessary conditions without differentiability assumptions in optimal control. Zbl 0272.49005
Warga, J.
1975
Optimal controls with pseudodelays. Zbl 0256.49010
Warga, J.
1974
Optimal control of differential and functional equations. Zbl 0253.49001
Warga, J.
1972
Normal control problems have no minimizing strictly original solutions. Zbl 0237.49004
Warga, J.
1971
Conflicting and minimax controls. Zbl 0186.49202
Warga, J.
1971
On a class of pursuit and evasion problems. Zbl 0206.45803
Warga, J.
1971
Comments on the paper ’Optimal control of processes described by integral equations. I’ by V. R. Vinokurov. Zbl 0206.16503
1970
Control problems with functional restrictions. Zbl 0205.16701
Warga, J.
1970
Unilateral and minimax control problems defined by integral equations. Zbl 0205.16801
Warga, J.
1970
Relaxed controls for functional equations. Zbl 0187.07904
Warga, J.
1970
The reduction of certain control problems to an ’ordinary differential’ type. Zbl 0155.14703
Warga, J.
1968
Functions of relaxed controls. Zbl 0234.49007
Warga, J.
1967
Restricted minima of functions of controls. Zbl 0234.49008
Warga, J.
1967
Variational problems with unbounded controls. Zbl 0201.47803
Warga, J.
1965
Minimax problems and unilateral curves in the calculus of variations. Zbl 0137.08302
Warga, J.
1965
On a class of minimax problems in the calculus of variations. Zbl 0133.36401
Warga, J.
1965
Unilateral variational problems with several inequalities. Zbl 0137.08401
Warga, J.
1965
Minimizing variational curves restricted to a preassigned set. Zbl 0129.07403
Warga, J.
1964
Minimizing certain convex functions. Zbl 0128.05801
Warga, J.
1963
A convergent procedure for solving the thermo-chemical equilibrium problem. Zbl 0199.22701
Warga, J.
1963
Relaxed variational problems. Zbl 0102.31801
Warga, J.
1962
Necessary conditions for minimum in relaxed variational problems. Zbl 0102.31802
Warga, J.
1962
On a class of iterative procedures for solving normal systems of ordinary differential equations. Zbl 0050.12303
Warga, J.
1953
On the representation of large integers as sums of primes. I. Zbl 0038.18602
Shapiro, Harold N.; Warga, Jack
1950
all top 5
all top 5
### Cited in 173 Serials
95 Journal of Optimization Theory and Applications 77 Journal of Mathematical Analysis and Applications 38 Proceedings of the Steklov Institute of Mathematics 24 Nonlinear Analysis. Theory, Methods & Applications 23 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 18 Applied Mathematics and Optimization 16 Journal of Applied Mathematics and Mechanics 16 Journal of Differential Equations 15 SIAM Journal on Control and Optimization 14 European Series in Applied and Industrial Mathematics (ESAIM): Control, Optimization and Calculus of Variations 13 Optimization 12 Numerical Functional Analysis and Optimization 11 Automation and Remote Control 10 International Journal of Control 10 Mathematical Notes 10 Journal of Mathematical Sciences (New York) 10 Set-Valued and Variational Analysis 9 Cybernetics 9 Systems & Control Letters 9 Cybernetics and Systems Analysis 9 Differential Equations 8 Transactions of the American Mathematical Society 8 Doklady Mathematics 8 Vestnik Udmurtskogo Universiteta. Matematika. Mekhanika. Komp’yuternye Nauki 7 Journal of Soviet Mathematics 7 Discrete and Continuous Dynamical Systems 6 International Journal of Systems Science 6 Prikladnaya Matematika i Mekhanika 6 Annali di Matematica Pura ed Applicata. Serie Quarta 6 Automatica 6 Computational Mathematics and Mathematical Physics 6 Russian Mathematics 6 Set-Valued Analysis 6 Mathematical Control and Related Fields 5 Archive for Rational Mechanics and Analysis 5 Applied Mathematics and Computation 5 Proceedings of the American Mathematical Society 5 Applied Mathematics Letters 5 Mathematical Programming. Series A. Series B 5 European Journal of Control 5 Journal of Dynamical and Control Systems 5 Nonlinear Analysis. Hybrid Systems 4 Computers & Mathematics with Applications 4 Stochastics 4 Siberian Mathematical Journal 4 Stochastic Analysis and Applications 4 Annales de l’Institut Henri Poincaré. Analyse Non Linéaire 4 Izvestiya Instituta Matematiki i Informatiki. Udmurtskiĭ Gosudarstvennyĭ Universitet 4 Journal of Dynamics and Games 4 Vestnik Rossiĭskikh Universitetov. Matematika 3 Zhurnal Vychislitel’noĭ Matematiki i Matematicheskoĭ Fiziki 3 Journal of Computational and Applied Mathematics 3 Journal of Functional Analysis 3 Kodai Mathematical Journal 3 Kybernetika 3 Mathematical and Computer Modelling 3 Journal of Global Optimization 3 SIAM Journal on Mathematical Analysis 3 SIAM Journal on Optimization 3 Journal of Inverse and Ill-Posed Problems 3 Bulletin of the American Mathematical Society 3 Discrete and Continuous Dynamical Systems. Series S 3 Minimax Theory and its Applications 3 Ural Mathematical Journal 2 Journal d’Analyse Mathématique 2 Ukrainian Mathematical Journal 2 Archiv der Mathematik 2 International Journal of Game Theory 2 Journal of Computer and System Sciences 2 Journal of Mathematical Economics 2 Manuscripta Mathematica 2 Monatshefte für Mathematik 2 Numerische Mathematik 2 Rendiconti del Circolo Matemàtico di Palermo. Serie II 2 Theoretical Computer Science 2 Acta Applicandae Mathematicae 2 MCSS. Mathematics of Control, Signals, and Systems 2 Japan Journal of Industrial and Applied Mathematics 2 Journal of Dynamics and Differential Equations 2 Journal of Computer and Systems Sciences International 2 Calculus of Variations and Partial Differential Equations 2 Mathematical Population Studies 2 Finance and Stochastics 2 Journal of Biological Systems 2 Discrete and Continuous Dynamical Systems. Series B 2 Journal of Applied Mathematics 2 Bulletin de la Société Mathématique de France. Supplément. Mémoires 2 Optimization Letters 2 Vestnik Samarskogo Gosudarstvennogo Tekhnicheskogo Universiteta. Seriya Fiziko-Matematicheskie Nauki 2 Dynamic Games and Applications 2 Izvestiya Irkutskogo Gosudarstvennogo Universiteta. Seriya Matematika 1 Analysis Mathematica 1 Applicable Analysis 1 Journal of the Franklin Institute 1 Mathematical Proceedings of the Cambridge Philosophical Society 1 Metrika 1 Periodica Mathematica Hungarica 1 Rocky Mountain Journal of Mathematics 1 Transport Theory and Statistical Physics 1 Zeitschrift für Angewandte Mathematik und Mechanik (ZAMM) ...and 73 more Serials
all top 5
### Cited in 37 Fields
493 Calculus of variations and optimal control; optimization (49-XX) 230 Systems theory; control (93-XX) 115 Operations research, mathematical programming (90-XX) 107 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 83 Ordinary differential equations (34-XX) 66 Numerical analysis (65-XX) 58 Partial differential equations (35-XX) 43 Real functions (26-XX) 40 Functional analysis (46-XX) 33 Probability theory and stochastic processes (60-XX) 32 General topology (54-XX) 29 Operator theory (47-XX) 26 Measure and integration (28-XX) 24 Global analysis, analysis on manifolds (58-XX) 19 Integral equations (45-XX) 13 Dynamical systems and ergodic theory (37-XX) 9 Computer science (68-XX) 9 Mechanics of particles and systems (70-XX) 9 Biology and other natural sciences (92-XX) 6 Convex and discrete geometry (52-XX) 6 Fluid mechanics (76-XX) 5 Mechanics of deformable solids (74-XX) 4 Number theory (11-XX) 4 Approximations and expansions (41-XX) 3 General and overarching topics; collections (00-XX) 3 History and biography (01-XX) 3 Mathematical logic and foundations (03-XX) 3 Difference and functional equations (39-XX) 3 Statistics (62-XX) 2 Functions of a complex variable (30-XX) 2 Manifolds and cell complexes (57-XX) 1 Topological groups, Lie groups (22-XX) 1 Harmonic analysis on Euclidean spaces (42-XX) 1 Differential geometry (53-XX) 1 Optics, electromagnetic theory (78-XX) 1 Statistical mechanics, structure of matter (82-XX) 1 Information and communication theory, circuits (94-XX)
### Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2022-05-17T17:33:03 |
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|
https://par.nsf.gov/biblio/10322449-progenitor-mass-dependent-yields-amplify-intrinsic-scatter-dwarf-galaxy-elemental-abundance-ratios
|
Progenitor-mass-dependent yields amplify intrinsic scatter in dwarf-galaxy elemental abundance ratios
ABSTRACT We explore the effect of including progenitor mass- and metallicity-dependent yields, supernova rates and energetics on variations in elemental abundance ratios (particularly [α/Fe]) in dwarf galaxies. To understand how the scatter and overall trends in [α/Fe] are affected by including variable metal yields from a discretely sampled initial mass function, we run FIRE simulations of a dwarf galaxy (M⋆(z = 0$) \sim 10^6\rm \, M_{\odot })$ using nucleosynthetic yields from the NuGrid data base that depend on the stellar progenitor mass and metallicity. While NuGrid exhibits lower aggregate α-element production than default FIRE yields, we find that its explicit mass dependence, even when including turbulent metal diffusion, substantially widens the intrinsic scatter in the simulated [Fe/H]-[α/Fe] – a phenomenon visible in some observations of dwarf galaxies.
Authors:
; ; ; ; ;
Award ID(s):
Publication Date:
NSF-PAR ID:
10322449
Journal Name:
Monthly Notices of the Royal Astronomical Society
Volume:
508
Issue:
1
ISSN:
0035-8711
2. ABSTRACT We present an analysis of spatially resolved gas-phase metallicity relations in five dwarf galaxies ($\rm \mathit{M}_{halo} \approx 10^{11}\, {\rm M}_\odot$, $\rm \mathit{M}_\star \approx 10^{8.8}{-}10^{9.6}\, {\rm M}_\odot$) from the FIRE-2 (Feedback in Realistic Environments) cosmological zoom-in simulation suite, which include an explicit model for sub-grid turbulent mixing of metals in gas, near z ≈ 0, over a period of 1.4 Gyr, and compare our findings with observations. While these dwarf galaxies represent a diverse sample, we find that all simulated galaxies match the observed mass–metallicity (MZR) and mass–metallicity gradient (MZGR) relations. We note that in all five galaxies, the metallicities are effectively identical between phases of the interstellar medium (ISM), with 95 ${{\ \rm per\ cent}}$ of the gas being within ±0.1 dex between the cold and dense gas (T < 500 K and nH > 1 cm−3), ionized gas (near the H αT ≈ 104 K ridge-line), and nebular regions (ionized gas where the 10 Myr-averaged star formation rate is non-zero). We find that most of the scatter in relative metallicity between cold dense gas and ionized gas/nebular regions can be attributed to either local starburst events or metal-poor inflows. We also note the presence of a major merger in one of our galaxies,more »
| 2023-02-02T22:31:01 |
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|
https://events.ncbj.gov.pl/event/10/timetable/?view=standard
|
# LSST-PL Meeting I
Europe/Warsaw
Description
LSST-PL Kick-Off Meeting
Participants
• Agnieszka Pollo
• Aleksander Herzig
• Aleksandra Olejak
• Anna Durkalec
• Artem Poliszczuk
• Boudewijn Roukema
• Bozena Czerny
• Chandra Shekhar Saraf
• Chetan Bavdhankar
• Katarzyna Kruszyńska
• Katarzyna Malek
• Katarzyna Wojczuk
• Krzysztof Rybicki
• Lukasz Wyrzykowski
• Maciek Bilicki
• Mary Loli Martínez-Aldama
• Marzena Sniegowska
• Mateusz Zieliński
• Małgorzata Bankowicz
• Michal Zajacek
• Michał Drahus
• Miguel Figueira
• Milena Ratajczak
• Pawel Bielewicz
• Paweł Zieliński
• Piotr Guzik
• Swayamtrupta Panda
• Szymon Nakoneczny
• Unnikrishnan Potty Sureshkumar
• Wojciech Hellwing
• Łukasz Stawarz
Contact
• 10:30 11:00
Welcome coffee and discussion 30m
• 11:00 11:20
0verview
• 11:00
Overview 20m
Overview of the LSST-PL collaboration status.
Speaker: Agnieszka Pollo (National Centre for Nuclear Research AND Jagiellonian University)
• 11:20 12:00
Galactic Science
• 11:20
Milky Way black hole population from lensing with the LSST 20m
Microlensing is the only tool to discover and study a population of hidden dark compact objects, including neutron stars, black holes and even the primordial black holes which could form part of the dark matter. We will show how LSST will contribute to this topic, with long-term whole sky observations and depth. We will discuss the lessons learned from Gaia and OGLE surveys which can be applied to LSST.
Speaker: Lukasz Wyrzykowski (Warsaw University Astronomical Observatory)
• 11:40
Tracking the nature of DM in the Local Universe 20m
I shall describe some promising features of our Local Universe that can help reveal some feature of a particle DM candidate. Simulations of galaxy and DM structure formation of warm, cold and self-interacting DM candidates indicate that features of the Galactic and M31 halo like: tidal streams gaps, satellite galaxies orbit parameter distribution and their internal properties can differ significantly in different DM candidate scenarios. Observations that the LSST will foster will allow us to use these features as potential DM tale-tell.
Speaker: Dr Wojciech Hellwing (CTF PAS)
• 12:00 13:00
AGNs
• 12:00
AGN variability with LSST 20m
I will discuss what science we can do using the six-color lightcurves from LSST for active galactic nuclei. This includes the power density spectra, structure functions, and time delays. In particular, time delay measurements can be used to do cosmology with quasars.
Speaker: Bozena Czerny (Center for Theoretical Physics)
• 12:20
Wavelength-dependent time delays in AGN accretion discs 10m
The idea of measuring and using wavelength-dependent time delays between
the optical continuum at different EM wavelengths in order to determine AGN
accretion disk structure has been known for many years. For example Sergeev et
al. (2005) modelled the lag-luminosity relation with a disc reprocessing model,
where time delays were caused by different light travel times from the ionizing
source and regions of continuum emission. Collier et al. (1999) gave an idea how
AGNs can be used in cosmology as standard candles by measuring the flux and
the time delays between the optical/UV continuum in an accretion disc. Right
now scientists, for example Cackett et al. 2007 fit the wavelength-dependent
time delays of AGNs with a disc reprocessing models, what allows to measure
the distances to the AGNs. However this method needs to be improved in order
to determine more accurate estimation of cosmological quantities such as the
Hubble constant. After that, it could be conveniently applied to six-color AGN
lightcuves from LSST.
Speaker: Ms Aleksandra Olejak (CFT PAN)
• 12:30
In search of CL AGN 10m
As was claimed in literature, CL AGN do not form the homogeneous sample. They vary widely in their timescale of phenomena or type of transient (from bright-state to dim-state or vice versa). The nature of state changes in CL AGN is still a mystery, however, different scenarios to explain these phenomena are proposed. I will discuss if CL AGN are a unique phenomenon and how we can identify them in the LSST sample.
Speaker: Marzena Sniegowska (CAMK PAN, CFT PAN)
• 12:40
Can reverberation-measured quasars be used for cosmology? 10m
Quasars have been proposed as a new class of standard candles such as
Supernovae, their large redshift range and high luminosities make them
excellent candidates. Reverberation mapping (RM) method offers to
estimate the distance to the source from the time delay measurement of
the emission lines with respect to the continuum, since the time delay
depends on the absolute luminosity of the source. This radius-luminosity
(RL) relation showed a low scatter and was proposed to use for the
cosmological purposes. However, in the recent years the increase of the
studied sample, and in particular the inclusion of highly accreting QSO
has increased the dispersion in the RL relation, with many objects
showing time delays shorter than the expected. Using Hb RM
measurements for 117 sources with a 0.2<z<0.9 and
41.5<L5100<45.9, we find a correction for the time
delay based on the dimensionless accretion rate. With this correction we
are able to build a Hubble diagram, which is in a good agreement with
the standard cosmological model.On the other hand, using the excess of
variability, we find that departure from the RL relation is associated
with the variability. Therefore variability is anti-correlated with the
accretion rate, indicating that accretion rate is one of main drivers of
QSO properties. Large multi-epoch surveys like LSST will be provide
variability features, which can be used as a tool in order to derive
other AGN physical properties.
Speaker: Dr Mary Loli Martínez-Aldama (CFT)
• 12:50
Photometric Reverberation Mapping using LSST 10m
An overview of our proposed project - Using a set of prepared AGN templates for a range of AGN parameters that are based on SED broadband modelling, we seek to calculate the contribution of the major lines (Hβ, Mg II, CIV) to the photometric channels, taking into account the Balmer continuum, FeII pseudo-continuum and other lines. The simulations will then be performed for representative objects using several cadences which are now under consideration. This method will improve the current standards of photometric reverberation method – using multi-channel and time-lag estimations from various methods.
Speaker: Mr Swayamtrupta Panda (Center for Theoretical Physics - PAS)
• 13:00 14:15
Lunch break 1h 15m
• 14:15 14:40
AGNs: AGNs II
• 14:15
Different time-delay measurement methods in reverberating AGN 10m
We will provide an overview of different methods how to reliably measure the time delay between the variable AGN continuum and the emission-line light curves in the broad line region (BLR) of active galactic nuclei. In particular, we will also discuss methods how to assess the uncertainties of these methods and how these errors can propagate further to the current models of the BLR.
Speaker: Michal Zajacek
• 14:25
Cosmological Evolution of the Radio-loudness of Quasar Sources 15m
I will present our (Singal et al. 2011, 2013) approach to the cosmological evolution of the radio-loudness parameter for quasar sources. In particular, I will show how we determine the radio and optical luminosity evolutions for a set of >5,000 quasars combining the SDSS and FORST data, based on the method of Efron and Petrosian (1993), to access the intrinsic distribution of the radio-loudness parameter (defined as the ratio of the radio to optical luminosity), taking into account the truncations and correlations inherent in the data. In this approach, we found that the intrinsic distribution of the radio-loudness is quite different from the observed one, is smooth with no evidence of a bimodality, and that the fraction of the radio-loud quasars increases with inscribing redshift (contrary to several claims presented in the literature).
Speaker: Prof. Lukasz Stawarz (Jagiellonian Univ., Krakow)
• 14:40 15:00
Solar System
• 14:40
Minor Body Science in the LSST Era 20m
Cataloging the Solar System is one of the main science themes that drive the LSST project. LSST is expected to discover ten times more objects from every minor body population than currently known, and provide hundreds of flux and color data for individual bodies. This will be a total game changer. On the one hand, transformative research will be done by the LSST community, but on the other hand, small body science will quickly fade in the communities having no access to these new discoveries and data. Our team wishes to join the LSST family and explore LSST data on every level. We will discuss examples of LSST-enabled minor body science based on (i) realtime alerts, (ii) daily orbit releases, (iii) annual catalog releases, and (iv) our own, customized deep stacks.
Speaker: Michał Drahus (OA UJ)
• 15:00 15:50
Galaxies and cosmology
• 15:00
LSST supernovae Ia and the turnaround epoch 20m
Galaxies form from primordial density perturbations that stop expanding and pass through a turnaround epoch, at which curvature is strongly positive: about five times as strong as density, when both are expressed as domain-averaged $\Omega$s. Moreover, a tight relation is expected between curvature and the domain-averaged expansion rate prior to turnaround. The high number density of LSST supernovae of type Ia that are followed up by spectroscopic redshifts should offer many opportunities for testing these two predictions of general relativity.
Speaker: Prof. Boudewijn Roukema (Toruń Centre for Astronomy, Nicolaus Copernicus University)
• 15:20
General LSS studies with LSST 20m
I envisage to use LSST data for general large-scale structure studies, in particular within the LSST Dark Energy Science Collaboration (DESC). Particular applications may include: photometric redshift derivation, application of resulting catalogs for such studies as tomographic angular clustering, galaxy-galaxy lensing, cross-correlations with CMB lensing etc. Other possible topics of interest are related to peculiar motions (large-scale flows etc.) using appropriate photometry-based techniques (e.g. Nusser et al. 2011) and/or transverse motions.
Speaker: Maciek Bilicki (CFT PAN & NCBJ)
• 15:40
SED fitting as a tool for searching peculiar galaxies 10m
I would like to use the SED technique for selection of galaxies which do not follow the energy balance like super dusty galaxies or possible lensing objects.
Speaker: Katarzyna Malek (NCBJ)
• 15:50 16:20
Coffee break 30m
• 16:20 16:55
Machine learning
• 16:20
Machine learning application to the LSST data 10m
I am planning to apply different machine learning methods to broad range of tasks, such as object classification based on both flux measurements and raw images, novelty detection and correction of the distorted images.
Speaker: Mr Artem Poliszczuk (NCBJ)
• 16:30
machine learning based quasar detection in photometric surveys 10m
Broad spectroscopic lines, large redshift range and variety of properties make quasar detection in photometric surveys a particularly difficult task, and estimation of their photometric redshifts is even more challenging. I will present a quasar detection method based on photometric ugri data in Kilo-Degree Survey (KIDS) - an imaging deep and wide field survey covering 447 sq. deg. on the sky (Nakoneczny et al. 2019). The KiDS third data release contains 49 millions of sources among which, however, a vast majority does not have any spectroscopically confirmed identification. We successfully trained a Random Forest classifier based on the KIDS data and a set of known quasars identified by the SDSS spectroscopic survey. Our final catalog consists of 190,000 quasar candidates and its training purity equals 91%. Additional validation of the catalog was made by the means of comparison with GAIA second data release, other already existing quasar catalogs and WISE photometric data. Our method can be easily applied to the future LSST data, and developed further to make use of the LSST time domain data.
Speaker: Mr Szymon Nakoneczny (National Centre for Nuclear Research, Astrophysics Division, Warsaw, Poland)
• 16:40
AI methods developed / under development for TOROS that might be use for LSST 15m
In a talk I would like to present methods developed or currently under development for TOROS project that have potential to be useful for LSST. Most important methods developed be me for TOROS is background rejection using Convolutional Neural Networks (with 99.5 % accuracy). The other methods currently under development involves galaxy subtraction using GANs, scheduling using reinforcement learning and image subtraction using neural networks.
| 2022-09-25T17:50:45 |
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|
https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/DT/PetscDTJacobiEvalJet.html
|
petsc-3.14.4 2021-02-03
Report Typos and Errors
# PetscDTJacobiEvalJet
Evaluate the jet (function and derivatives) of the Jacobi polynomials basis up to a given degree. The Jacobi polynomials with indices $\alpha$ and $\beta$ are orthogonal with respect to the weighted inner product $\langle f, g \rangle = \int_{-1}^1 (1+x)^{\alpha} (1-x)^{\beta) f(x) g(x) dx$.
### Synopsis
#include "petscdt.h"
PetscErrorCode PetscDTJacobiEvalJet(PetscReal alpha, PetscReal beta, PetscInt npoints, const PetscReal points[], PetscInt degree, PetscInt k, PetscReal p[])
### Input Arguments
alpha - the left exponent of the weight beta - the right exponetn of the weight npoints - the number of points to evaluate the polynomials at points - [npoints] array of point coordinates degree - the maximm degree polynomial space to evaluate, (degree + 1) will be evaluated total. k - the maximum derivative to evaluate in the jet, (k + 1) will be evaluated total.
### Output Argments
p - an array containing the evaluations of the Jacobi polynomials's jets on the points. the size is (degree + 1) x (k + 1) x npoints, which also describes the order of the dimensions of this three-dimensional array: the first (slowest varying) dimension is polynomial degree; the second dimension is derivative order; the third (fastest varying) dimension is the index of the evaluation point.
### See Also
PetscDTJacobiEval(), PetscDTPKDEvalJet()
advanced
### Location
src/dm/dt/interface/dt.c
Index of all DT routines
Table of Contents for all manual pages
Index of all manual pages
| 2021-02-27T13:39:09 |
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|
https://zbmath.org/authors/?q=ai%3Abach.volker
|
## Bach, Volker
Compute Distance To:
Author ID: bach.volker Published as: Bach, Volker; Bach, V. External Links: MGP · Wikidata · GND
Documents Indexed: 64 Publications since 1989, including 1 Book 4 Contributions as Editor Co-Authors: 42 Co-Authors with 53 Joint Publications 805 Co-Co-Authors
all top 5
### Co-Authors
14 single-authored 16 Fröhlich, Jürg Martin 13 Sigal, Israel Michael 6 Ballesteros, Miguel 5 Pizzo, Alessandro 4 Breteaux, Sébastien 4 Chen, Thomas M. 4 Siedentop, Heinz Karl Heinrich 3 Barbaroux, Jean-Marie 3 Knörr, Hans Konrad 3 Lieb, Elliott Hershel 3 Menge, Edmund 3 Møller, Jacob Schach 2 Bru, Jean-Bernard 2 De Siqueira Pedra, Walter 2 Hach, Alexander 2 Helffer, Bernard 2 Jonsson, Lars-Erik 2 Könenberg, Martin 2 Menrath, Lars 2 Poelchau, Jurij 2 Solovej, Jan Philip 2 Tzaneteas, Tim 1 Deckert, Dirk-André 1 Dereziński, Jan 1 Faupin, Jérémy 1 Hoppe, Jens 1 Iniesta, Diego 1 Jecko, Thierry 1 Klopp, Frédéric 1 Kurig, Carolin 1 Lewis, Roger T. 1 Lundholm, Douglas 1 Matte, Oliver 1 Merkli, Marco 1 Petrat, Sören 1 Pickl, Peter 1 Seiler, Ruedi 1 Sjöstrand, Johannes 1 Soffer, Avraham 1 Travaglia, Marcos Vinicio 1 Urban, Karsten 1 Zenk, Heribert
all top 5
### Serials
7 Communications in Mathematical Physics 6 Journal of Mathematical Physics 5 Journal of Functional Analysis 4 Advances in Mathematics 4 Documenta Mathematica 4 Journal of Evolution Equations 3 Journal of Statistical Physics 3 Letters in Mathematical Physics 3 Mitteilungen der Deutschen Mathematiker-Vereinigung (DMV) 3 Annales Henri Poincaré 3 Oberwolfach Reports 2 Journal of Mathematical Analysis and Applications 2 Advances in Theoretical and Mathematical Physics 1 IEEE Transactions on Information Theory 1 Reports on Mathematical Physics 1 Reviews in Mathematical Physics 1 Journal of Differential Equations 1 Mathematische Zeitschrift 1 Memoirs of the American Mathematical Society 1 Journal de Mathématiques Pures et Appliquées. Neuvième Série 1 Random Operators and Stochastic Equations 1 Markov Processes and Related Fields 1 PAMM. Proceedings in Applied Mathematics and Mechanics
all top 5
### Fields
54 Quantum theory (81-XX) 18 Operator theory (47-XX) 14 Partial differential equations (35-XX) 12 Statistical mechanics, structure of matter (82-XX) 4 General and overarching topics; collections (00-XX) 4 Probability theory and stochastic processes (60-XX) 3 Ordinary differential equations (34-XX) 3 Mathematics education (97-XX) 2 Functional analysis (46-XX) 1 Linear and multilinear algebra; matrix theory (15-XX) 1 Dynamical systems and ergodic theory (37-XX) 1 Difference and functional equations (39-XX) 1 Calculus of variations and optimal control; optimization (49-XX) 1 Global analysis, analysis on manifolds (58-XX) 1 Numerical analysis (65-XX) 1 Mechanics of deformable solids (74-XX) 1 Fluid mechanics (76-XX) 1 Astronomy and astrophysics (85-XX) 1 Information and communication theory, circuits (94-XX)
### Citations contained in zbMATH Open
48 Publications have been cited 903 times in 468 Documents Cited by Year
Quantum electrodynamics of confined nonrelativistic particles. Zbl 0923.47040
Bach, Volker; Fröhlich, Jürg; Sigal, Israel Michael
1998
Spectral analysis for systems of atoms and molecules coupled to the quantized radiation field. Zbl 0965.81134
Bach, Volker; Fröhlich, Jürg; Sigal, Israel Michael
1999
Renormalization group analysis of spectral problems in quantum field theory. Zbl 0923.47041
Bach, Volker; Fröhlich, Jürg; Sigal, Israel Michael
1998
Generalized Hartree-Fock theory and the Hubbard model. Zbl 0839.60095
Bach, Volker; Lieb, Elliott H.; Solovej, Jan Philip
1994
Bach, Volker; Fröhlich, Jürg; Sigal, Israel Michael
2000
Error bound for the Hartree-Fock energy of atoms and molecules. Zbl 0771.46038
Bach, Volker
1992
Smooth Feshbach map and operator-theoretic renormalization group methods. Zbl 1060.47028
Bach, Volker; Chen, Thomas; Fröhlich, Jürg; Sigal, Israel Michael
2003
Infrared-finite algorithms in QED: the groundstate of an atom interacting with the quantized radiation field. Zbl 1118.81083
Bach, Volker; Fröhlich, Jürg; Pizzo, Alessandro
2006
The renormalized electron mass in non-relativistic quantum electrodynamics. Zbl 1118.81028
Bach, Volker; Chen, Thomas; Fröhlich, Jürg; Sigal, Israel Michael
2007
Positive commutators and the spectrum of Pauli-Fierz Hamiltonian of atoms and molecules. Zbl 0962.81011
Bach, Volker; Fröhlich, Jürg; Sigal, Israel Michael; Soffer, Avy
1999
Mathematical theory of nonrelativistic matter and radiation. Zbl 0831.47048
Bach, V.; Fröhlich, J.; Sigal, I. M.
1995
Kinetic energy estimates for the accuracy of the time-dependent Hartree-Fock approximation with Coulomb interaction. Zbl 1333.35221
Bach, Volker; Breteaux, Sébastien; Petrat, Sören; Pickl, Peter; Tzaneteas, Tim
2016
On the stability of the relativistic electron-positron field. Zbl 1024.81056
Bach, Volker; Barbaroux, Jean-Marie; Helffer, Bernard; Siedentop, Heinz
1999
Accuracy of mean field approximations for atoms and molecules. Zbl 0802.47061
Bach, Volker
1993
Correlation at low temperature. I: Exponential decay. Zbl 1031.82003
Bach, Volker; Møller, Jacob Schach
2003
Infrared-finite algorithms in QED. II. The expansion of the groundstate of an atom interacting with the quantized radiation field. Zbl 1161.81026
Bach, Volker; Fröhlich, Jürg; Pizzo, Alessandro
2009
Ionization energies of bosonic Coulomb systems. Zbl 0725.47049
Bach, Volker
1991
Existence of ground state eigenvalues for the spin-boson model with critical infrared divergence and multiscale analysis. Zbl 1366.81317
Bach, Volker; Ballesteros, Miguel; Könenberg, Martin; Menrath, Lars
2017
Correlation asymptotics of classical lattice spin systems with nonconvex Hamilton function at low temperature. Zbl 1021.82002
Bach, V.; Jecko, T.; Sjöstrand, J.
2000
An infrared-finite algorithm for Rayleigh scattering amplitudes, and Bohr’s frequency condition. Zbl 1123.81046
Bach, Volker; Fröhlich, Jürg; Pizzo, Alessandro
2007
A proof of Scott’s conjecture for ions. Zbl 0732.58042
Bach, Volker
1989
Effective dynamics of an electron coupled to an external potential in non-relativistic QED. Zbl 1275.81091
Bach, Volker; Chen, Thomas; Faupin, Jérémy; Fröhlich, Jürg; Sigal, Israel Michael
2013
Bounds on the discrete spectrum of lattice Schrödinger operators. Zbl 1382.81094
Bach, V.; de Siqueira Pedra, W.; Lakaev, S. N.
2018
Existence and construction of resonances for atoms coupled to the quantized radiation field. Zbl 1366.81318
Bach, Volker; Ballesteros, Miguel; Pizzo, Alessandro
2017
Mathematical analysis of the photoelectric effect. Zbl 1015.81059
Bach, Volker; Klopp, Frédéric; Zenk, Heribert
2001
On the number of bound states of a bosonic $$N$$-particle Coulomb system. Zbl 0852.47036
Bach, Volker; Lewis, Roger; Lieb, Elliott H.; Siedentop, Heinz
1993
Bogolubov-Hartree-Fock mean field theory for neutron stars and other systems with attractive interactions. Zbl 1248.81277
Bach, Volker; Fröhlich, Jürg; Jonsson, Lars
2009
Diagonalizing quadratic bosonic operators by non-autonomous flow equation. Zbl 1435.81003
Bach, Volker; Bru, Jean-Bernard
2016
Continuous renormalization group analysis of spectral problems in quantum field theory. Zbl 1308.81086
Bach, Volker; Ballesteros, Miguel; Fröhlich, Jürg
2015
Construction of the ground state in nonrelativistic QED by continuous flows. Zbl 1107.81050
Bach, Volker; Könenberg, Martin
2006
Suppression of decoherence by periodic forcing. Zbl 1300.81010
Bach, Volker; de Siqueira Pedra, Walter; Merkli, Marco; Sigal, Israel Michael
2014
Rigorous foundations of the Brockett-Wegner flow for operators. Zbl 1239.34067
Bach, Volker; Bru, Jean-Bernard
2010
Generalization of Lieb’s variational principle to Bogoliubov-Hartree-Fock theory. Zbl 1295.81146
Bach, Volker; Breteaux, Sébastien; Knörr, Hans Konrad; Menge, Edmund
2014
Accuracy of the Hartree-Fock approximation for the Hubbard model. Zbl 0883.60100
Bach, Volker; Poelchau, Jurij
1997
Stability of matter for the Hartree-Fock functional of the relativistic electron-positron field. Zbl 0913.35113
Bach, Volker; Barbaroux, Jean-Marie; Helffer, Bernard; Siedentop, Heinz
1998
Minimization of the energy of the nonrelativistic one-electron Pauli-Fierz model over quasifree states. Zbl 1291.81401
Bach, Volker; Breteaux, Sébastien; Tzaneteas, Tim
2013
Hartree-Fock Gibbs states for the Hubbard model. Zbl 0878.60076
Bach, V.; Poelchau, J.
1996
Exponential decay of eigenfunctions of the Bethe-Salpeter operator. Zbl 0991.34074
Bach, Volker; Matte, Oliver
2001
Correlation at low temperature. II: Asymptotics. Zbl 1142.82311
Bach, Volker; Møller, Jacob Schach
2004
Ferromagnetism of the Hubbard model at strong coupling in the Hartree-Fock approximation. Zbl 1125.82031
Bach, Volker; Lieb, Elliott H.; Travaglia, Marcos V.
2006
Mathematical density and density matrix functional theory (DFT and DMFT). Zbl 1329.81421
Bach, Volker
2013
Dynamical symmetries in supersymmetric matrix models. Zbl 1160.81025
Bach, V.; Hoppe, J.; Lundholm, D.
2008
Mass renormalization in nonrelativistic quantum electrodynamics. Zbl 1309.81290
Bach, Volker
2012
A tutorial approach to the renormalization group and the smooth Feshbach map. Zbl 1105.81057
Bach, V.
2006
Universality of the Fermi-Hellmann model. Zbl 0737.34042
Bach, Volker; Siedentop, Heinz
1991
Bach, Volker
2001
Fermion correlation inequalities derived from G- and P-conditions. Zbl 1260.81337
Bach, Volker; Knörr, Hans Konrad; Menge, Edmund
2012
QED of confined nonrelativistic particles – new results. Zbl 1253.81133
Bach, Volker; Fröhlich, Jürg; Sigal, Israel Michael
1999
Bounds on the discrete spectrum of lattice Schrödinger operators. Zbl 1382.81094
Bach, V.; de Siqueira Pedra, W.; Lakaev, S. N.
2018
Existence of ground state eigenvalues for the spin-boson model with critical infrared divergence and multiscale analysis. Zbl 1366.81317
Bach, Volker; Ballesteros, Miguel; Könenberg, Martin; Menrath, Lars
2017
Existence and construction of resonances for atoms coupled to the quantized radiation field. Zbl 1366.81318
Bach, Volker; Ballesteros, Miguel; Pizzo, Alessandro
2017
Kinetic energy estimates for the accuracy of the time-dependent Hartree-Fock approximation with Coulomb interaction. Zbl 1333.35221
Bach, Volker; Breteaux, Sébastien; Petrat, Sören; Pickl, Peter; Tzaneteas, Tim
2016
Diagonalizing quadratic bosonic operators by non-autonomous flow equation. Zbl 1435.81003
Bach, Volker; Bru, Jean-Bernard
2016
Continuous renormalization group analysis of spectral problems in quantum field theory. Zbl 1308.81086
Bach, Volker; Ballesteros, Miguel; Fröhlich, Jürg
2015
Suppression of decoherence by periodic forcing. Zbl 1300.81010
Bach, Volker; de Siqueira Pedra, Walter; Merkli, Marco; Sigal, Israel Michael
2014
Generalization of Lieb’s variational principle to Bogoliubov-Hartree-Fock theory. Zbl 1295.81146
Bach, Volker; Breteaux, Sébastien; Knörr, Hans Konrad; Menge, Edmund
2014
Effective dynamics of an electron coupled to an external potential in non-relativistic QED. Zbl 1275.81091
Bach, Volker; Chen, Thomas; Faupin, Jérémy; Fröhlich, Jürg; Sigal, Israel Michael
2013
Minimization of the energy of the nonrelativistic one-electron Pauli-Fierz model over quasifree states. Zbl 1291.81401
Bach, Volker; Breteaux, Sébastien; Tzaneteas, Tim
2013
Mathematical density and density matrix functional theory (DFT and DMFT). Zbl 1329.81421
Bach, Volker
2013
Mass renormalization in nonrelativistic quantum electrodynamics. Zbl 1309.81290
Bach, Volker
2012
Fermion correlation inequalities derived from G- and P-conditions. Zbl 1260.81337
Bach, Volker; Knörr, Hans Konrad; Menge, Edmund
2012
Rigorous foundations of the Brockett-Wegner flow for operators. Zbl 1239.34067
Bach, Volker; Bru, Jean-Bernard
2010
Infrared-finite algorithms in QED. II. The expansion of the groundstate of an atom interacting with the quantized radiation field. Zbl 1161.81026
Bach, Volker; Fröhlich, Jürg; Pizzo, Alessandro
2009
Bogolubov-Hartree-Fock mean field theory for neutron stars and other systems with attractive interactions. Zbl 1248.81277
Bach, Volker; Fröhlich, Jürg; Jonsson, Lars
2009
Dynamical symmetries in supersymmetric matrix models. Zbl 1160.81025
Bach, V.; Hoppe, J.; Lundholm, D.
2008
The renormalized electron mass in non-relativistic quantum electrodynamics. Zbl 1118.81028
Bach, Volker; Chen, Thomas; Fröhlich, Jürg; Sigal, Israel Michael
2007
An infrared-finite algorithm for Rayleigh scattering amplitudes, and Bohr’s frequency condition. Zbl 1123.81046
Bach, Volker; Fröhlich, Jürg; Pizzo, Alessandro
2007
Infrared-finite algorithms in QED: the groundstate of an atom interacting with the quantized radiation field. Zbl 1118.81083
Bach, Volker; Fröhlich, Jürg; Pizzo, Alessandro
2006
Construction of the ground state in nonrelativistic QED by continuous flows. Zbl 1107.81050
Bach, Volker; Könenberg, Martin
2006
Ferromagnetism of the Hubbard model at strong coupling in the Hartree-Fock approximation. Zbl 1125.82031
Bach, Volker; Lieb, Elliott H.; Travaglia, Marcos V.
2006
A tutorial approach to the renormalization group and the smooth Feshbach map. Zbl 1105.81057
Bach, V.
2006
Correlation at low temperature. II: Asymptotics. Zbl 1142.82311
Bach, Volker; Møller, Jacob Schach
2004
Smooth Feshbach map and operator-theoretic renormalization group methods. Zbl 1060.47028
Bach, Volker; Chen, Thomas; Fröhlich, Jürg; Sigal, Israel Michael
2003
Correlation at low temperature. I: Exponential decay. Zbl 1031.82003
Bach, Volker; Møller, Jacob Schach
2003
Mathematical analysis of the photoelectric effect. Zbl 1015.81059
Bach, Volker; Klopp, Frédéric; Zenk, Heribert
2001
Exponential decay of eigenfunctions of the Bethe-Salpeter operator. Zbl 0991.34074
Bach, Volker; Matte, Oliver
2001
Bach, Volker
2001
Bach, Volker; Fröhlich, Jürg; Sigal, Israel Michael
2000
Correlation asymptotics of classical lattice spin systems with nonconvex Hamilton function at low temperature. Zbl 1021.82002
Bach, V.; Jecko, T.; Sjöstrand, J.
2000
Spectral analysis for systems of atoms and molecules coupled to the quantized radiation field. Zbl 0965.81134
Bach, Volker; Fröhlich, Jürg; Sigal, Israel Michael
1999
Positive commutators and the spectrum of Pauli-Fierz Hamiltonian of atoms and molecules. Zbl 0962.81011
Bach, Volker; Fröhlich, Jürg; Sigal, Israel Michael; Soffer, Avy
1999
On the stability of the relativistic electron-positron field. Zbl 1024.81056
Bach, Volker; Barbaroux, Jean-Marie; Helffer, Bernard; Siedentop, Heinz
1999
QED of confined nonrelativistic particles – new results. Zbl 1253.81133
Bach, Volker; Fröhlich, Jürg; Sigal, Israel Michael
1999
Quantum electrodynamics of confined nonrelativistic particles. Zbl 0923.47040
Bach, Volker; Fröhlich, Jürg; Sigal, Israel Michael
1998
Renormalization group analysis of spectral problems in quantum field theory. Zbl 0923.47041
Bach, Volker; Fröhlich, Jürg; Sigal, Israel Michael
1998
Stability of matter for the Hartree-Fock functional of the relativistic electron-positron field. Zbl 0913.35113
Bach, Volker; Barbaroux, Jean-Marie; Helffer, Bernard; Siedentop, Heinz
1998
Accuracy of the Hartree-Fock approximation for the Hubbard model. Zbl 0883.60100
Bach, Volker; Poelchau, Jurij
1997
Hartree-Fock Gibbs states for the Hubbard model. Zbl 0878.60076
Bach, V.; Poelchau, J.
1996
Mathematical theory of nonrelativistic matter and radiation. Zbl 0831.47048
Bach, V.; Fröhlich, J.; Sigal, I. M.
1995
Generalized Hartree-Fock theory and the Hubbard model. Zbl 0839.60095
Bach, Volker; Lieb, Elliott H.; Solovej, Jan Philip
1994
Accuracy of mean field approximations for atoms and molecules. Zbl 0802.47061
Bach, Volker
1993
On the number of bound states of a bosonic $$N$$-particle Coulomb system. Zbl 0852.47036
Bach, Volker; Lewis, Roger; Lieb, Elliott H.; Siedentop, Heinz
1993
Error bound for the Hartree-Fock energy of atoms and molecules. Zbl 0771.46038
Bach, Volker
1992
Ionization energies of bosonic Coulomb systems. Zbl 0725.47049
Bach, Volker
1991
Universality of the Fermi-Hellmann model. Zbl 0737.34042
Bach, Volker; Siedentop, Heinz
1991
A proof of Scott’s conjecture for ions. Zbl 0732.58042
Bach, Volker
1989
all top 5
### Cited by 366 Authors
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### Cited in 81 Serials
67 Journal of Mathematical Physics 62 Communications in Mathematical Physics 39 Journal of Statistical Physics 37 Journal of Functional Analysis 36 Annales Henri Poincaré 35 Reviews in Mathematical Physics 20 Letters in Mathematical Physics 18 Advances in Mathematics 14 Journal of Mathematical Analysis and Applications 10 Archive for Rational Mechanics and Analysis 6 Mathematical Physics, Analysis and Geometry 5 Séminaire Laurent Schwartz. EDP et Applications 4 Communications on Pure and Applied Mathematics 4 Reports on Mathematical Physics 4 Theoretical and Mathematical Physics 4 M$$^3$$AS. Mathematical Models & Methods in Applied Sciences 4 Journal de Mathématiques Pures et Appliquées. Neuvième Série 4 Calculus of Variations and Partial Differential Equations 4 Journal of Evolution Equations 3 Annales de l’Institut Henri Poincaré. Physique Théorique 3 Infinite Dimensional Analysis, Quantum Probability and Related Topics 3 Comptes Rendus. Mathématique. Académie des Sciences, Paris 2 International Journal of Modern Physics B 2 Physics Reports 2 Integral Equations and Operator Theory 2 Inventiones Mathematicae 2 Journal of Differential Equations 2 Mathematische Zeitschrift 2 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 2 Publications of the Research Institute for Mathematical Sciences, Kyoto University 2 Transactions of the American Mathematical Society 2 Annales de l’Institut Henri Poincaré. Analyse Non Linéaire 2 Communications in Partial Differential Equations 2 SIAM Journal on Mathematical Analysis 2 Bulletin of the American Mathematical Society. New Series 2 St. Petersburg Mathematical Journal 2 Advances in Mathematical Physics 2 Journal de l’École Polytechnique – Mathématiques 2 Pure and Applied Analysis 1 International Journal of Modern Physics A 1 Applicable Analysis 1 Nuclear Physics. B 1 Russian Mathematical Surveys 1 Journal of Geometry and Physics 1 Acta Mathematica 1 Annales Scientifiques de l’École Normale Supérieure. Quatrième Série 1 Duke Mathematical Journal 1 Hokkaido Mathematical Journal 1 International Journal of Mathematics and Mathematical Sciences 1 Journal of Mathematical Economics 1 Memoirs of the American Mathematical Society 1 Proceedings of the American Mathematical Society 1 Transactions of the Moscow Mathematical Society 1 Advances in Applied Mathematics 1 Rendiconti di Matematica e delle sue Applicazioni. Serie VII 1 Applied Mathematics Letters 1 Sugaku Expositions 1 Stochastic Processes and their Applications 1 Mémoires de la Société Mathématique de France. Nouvelle Série 1 Journal of Nonlinear Science 1 Kyushu Journal of Mathematics 1 Discrete and Continuous Dynamical Systems 1 New Journal of Physics 1 Journal of the European Mathematical Society (JEMS) 1 Lobachevskii Journal of Mathematics 1 Physical Review Letters 1 Quantum Information Processing 1 Journal of Hyperbolic Differential Equations 1 Journal of Statistical Mechanics: Theory and Experiment 1 Boundary Value Problems 1 European Series in Applied and Industrial Mathematics (ESAIM): Mathematical Modelling and Numerical Analysis 1 SIGMA. Symmetry, Integrability and Geometry: Methods and Applications 1 Complex Analysis and Operator Theory 1 Journal of Physics A: Mathematical and Theoretical 1 Analysis & PDE 1 Journal of Pseudo-Differential Operators and Applications 1 Kyoto Journal of Mathematics 1 Journal of Spectral Theory 1 Bulletin of Mathematical Sciences 1 EMS Surveys in Mathematical Sciences 1 Tunisian Journal of Mathematics
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### Cited in 35 Fields
378 Quantum theory (81-XX) 153 Statistical mechanics, structure of matter (82-XX) 141 Partial differential equations (35-XX) 108 Operator theory (47-XX) 36 Functional analysis (46-XX) 25 Probability theory and stochastic processes (60-XX) 13 Global analysis, analysis on manifolds (58-XX) 13 Optics, electromagnetic theory (78-XX) 11 Calculus of variations and optimal control; optimization (49-XX) 10 Dynamical systems and ergodic theory (37-XX) 8 Ordinary differential equations (34-XX) 8 Mechanics of particles and systems (70-XX) 7 Difference and functional equations (39-XX) 5 Functions of a complex variable (30-XX) 5 Astronomy and astrophysics (85-XX) 4 Relativity and gravitational theory (83-XX) 3 Differential geometry (53-XX) 3 Information and communication theory, circuits (94-XX) 2 Combinatorics (05-XX) 2 Measure and integration (28-XX) 2 Integral equations (45-XX) 2 Statistics (62-XX) 2 Fluid mechanics (76-XX) 2 Classical thermodynamics, heat transfer (80-XX) 1 History and biography (01-XX) 1 Algebraic geometry (14-XX) 1 Linear and multilinear algebra; matrix theory (15-XX) 1 Group theory and generalizations (20-XX) 1 Topological groups, Lie groups (22-XX) 1 Approximations and expansions (41-XX) 1 Integral transforms, operational calculus (44-XX) 1 Numerical analysis (65-XX) 1 Computer science (68-XX) 1 Mechanics of deformable solids (74-XX) 1 Game theory, economics, finance, and other social and behavioral sciences (91-XX)
### Wikidata Timeline
The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.
| 2022-08-14T22:42:12 |
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http://www.scstatehouse.gov/amendments.php?KEY=22856
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View Amendment Current Amendment: 4 to Bill 4813 Rep. BINGHAM proposes the following Amendment No. to H.4813 as introduced by Ways & Means
(Doc Name h:\legwork\house\amend\H-WM\004\BUDGET SECTION REFERENCE CHANGES - GENERAL FUND.DOCX):
EXPLANATION: Changes the budget section reference in all Section 1 provisos to conform with restructuring at the Department
Amend the bill, as and if amended, Part IB, Section 1, DEPARTMENT OF EDUCATION, page 327, paragraph 1.16, line 21, by striking /XIII/ and inserting /XIV/
Amend the bill further, as and if amended, Section 1, DEPARTMENT OF EDUCATION, page 327, paragraph 1.18, line 31, by striking /XV/ and inserting /IV/
Amend the bill further, as and if amended, Section 1, DEPARTMENT OF EDUCATION, page 328, paragraph 1.25, line 32, by striking /IX/ and inserting /X/
Amend the bill further, as and if amended, Section 1, DEPARTMENT OF EDUCATION, page 329, paragraph 1.28, line 13, by striking /IX/ and inserting /X/ and line 14, by striking /IX/ and inserting /X/
Amend the bill further, as and if amended, Section 1, DEPARTMENT OF EDUCATION, page 332, paragraph 1.39, line 14, by striking /IX/ and inserting /X/
Amend the bill further, as and if amended, Section 1, DEPARTMENT OF EDUCATION, page 339, paragraph 1.74, line 10, by striking /X/ and inserting /XI/
Renumber sections to conform.
Amend totals and titles to conform.
| 2018-05-23T11:14:05 |
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https://www.abs.gov.au/methodologies/tourist-accommodation-small-area-data-australia-methodology/jun-2013
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This release has ceased
# Tourist Accommodation, Small Area Data, Australia methodology
Reference period
June 2013
Released
26/09/2013
Next release Ceased
First release
## Explanatory notes
### Introduction
1 This publication presents data from the quarterly Survey of Tourist Accommodation (STA). The STA completely enumerates all in-scope accommodation establishments within Australia. From 1 July 2013 the collection frequency of the STA moved from quarterly to annual, on a financial year basis. The next release of STA data will be on 19 December 2014 and will include the four quarters of the 2013-14 financial year, that is September quarter 2013, December quarter 2013, March quarter 2014 and June quarter 2014.
### Scope
2 Establishments within the scope of the survey provide predominantly short-term non-residential accommodation, i.e. accommodation which is not leased, and which is provided to guests who would generally stay for periods of less than two months. Some of these establishments also provide long-term residential accommodation. The amount of such activity is considered to be insignificant and is included in the data presented in this publication.
3 Establishments in scope of the STA are:
• hotels and resorts with 15 or more rooms
• motels, private hotels and guest houses with 15 or more rooms
• serviced apartments with 15 or more units.
### Coverage
4 The main source of coverage is from the Australian Automobile Association through AAA Tourism Pty Ltd. Updates are generally undertaken each quarter through information supplied to the ABS by AAA Tourism.
5 The AAA Tourism updates are supplemented by notification of new tourism developments and their likely opening dates in selected guides, major tourism journals, periodicals and newspapers. Periodic comparison with lists of accommodation establishments provided by the various tourism organisations and industry associations is also undertaken.
6 Data by star grade for states and territories are included in Tourist Accommodation, Small Area Data (cat. no. 8635.0.55.002 for national data and cat. no. 8635.1.55.001 - 8635.8.55.001 for state/territory data).
### Statistical geography
7 Small area statistics for 2013 are classified to the Australian Statistical Geography Standard (ASGS), 2012 Edition (cat. no. 1270.0.55.001) effective from March quarter 2013.
8 Small area data (SA2) are aggregated to tourism regions as defined by relevant state and territory tourism organisations. Tourism regions are reviewed annually and are subject to boundary and name changes. Where changes have occurred, care should be taken when making comparisons with previously published data at this level.
9 Data by tourism regions and small area (SA2) are not presented in this publication but are available in Tourist Accommodation, Small Area Data (cat. no. 8635.0.55.002 for national data and cat. no. 8635.1.55.001 - 8635.8.55.001 for state/territory data).
10 Details of the composition of tourism regions and maps of tourism regions are provided in the ABS publication Tourism Region Maps and Correspondence File (cat. no. 9503.0.55.001) available from the ABS web site www.abs.gov.au.
### Data quality
11 The survey does not have a sample component and the data are not subject to sampling variability. However, other inaccuracies collectively referred to as non-sampling error may affect the data. These non-sampling errors may arise from a number of sources, including:
• errors in the reporting of data by providers
• errors in the process of capturing data
• imputation for missing data
• definition and classification errors
• incomplete coverage.
12 Every effort has been made to reduce non-sampling error to a minimum by careful design and testing of questionnaires, and efficient operating procedures and systems used to compile statistics.
### Response rates
13 The quality and reliability of survey data can be affected by the degree of response to a survey however, it is rare to achieve a 100% response rate for any survey. The response rates for the Survey of Tourist Accommodation at state level are shown below.
Jun Qtr 2012Sep Qtr 2012Dec Qtr 2012Mar Qtr 2013Jun Qtr 2013
%%%%%
NSWr89.4r86.490.587.587.2
Vic.r90.0r88.190.689.689.3
Qldr90.6r87.688.590.188.2
SAr89.5r89.492.888.790.9
WAr88.6r92.191.390.490.2
Tas.r92.1r86.887.088.291.9
NTr81.7r82.885.176.684.8
ACTr94.0r93.996.088.096.0
Aust.r89.8r87.790.088.788.6
r revised
a. Due to a systems issue, some late responding units had been incorrectly treated in the calculation of response rates. This resulted in published response rates being slightly higher than they should have been. The issue has now been corrected, and as a result response rates for previous quarters have been revised.
### Imputation rates
14 Missing data items are replaced by imputed values based on reported data. Average quarterly movements are applied to previously reported data for each non-responding unit to estimate values for missing data items. Only if previously reported data are not available, will data from a similar unit be used as a 'donor' for the missing data items.
15 The imputation rates for Room night occupied and Takings from accommodation for the most recent quarters at a national level are shown below.
Jun Qtr 2012Sep Qtr 2012Dec Qtr 2012Mar Qtr 2013Jun Qtr 2013
%%%%%
Motels, private hotels and guest housesr9.7r12.19.710.310.9
Serviced apartmentsr7.4r7.75.76.46.5
Hotels, motels and serviced apartmentsr8.7r8.86.67.98.2
r revised
a. An error was found in the way imputation rates were being calculated, resulting in published rates being lower than they should have been. The issue has now been corrected, and as a result imputation rates for previous quarters have been revised.
### Imputation rates(a), room nights occupied
Jun Qtr 2012Sep Qtr 2012Dec Qtr 2012Mar Qtr 2013Jun Qtr 2013
%%%%%
Motels, private hotels and guest housesr9.6r12.010.09.910.9
Serviced apartmentsr6.8r7.95.66.46.2
Hotels, motels and serviced apartmentsr8.2r8.05.97.27.3
r revised
a. An error was found in the way imputation rates were being calculated, resulting in published rates being lower than they should have been. The issue has now been corrected, and as a result imputation rates for previous quarters have been revised.
### Imputation rates(a), takings from accommodation
16 Seasonal adjustment is a means of removing the estimated effects of normal seasonal variation from the original time series so that the effect of other influences on the series may be more clearly recognised. Seasonal adjustment procedures do not aim to remove the irregular or non-seasonal influences which may be present in any particular quarter. Irregular influences that are highly volatile can make it difficult to interpret the movement of the series even after adjustment for seasonal variation, and cannot be assumed to indicate changes in the trend.
17 The seasonally adjusted estimates in this publication have been produced using a concurrent methodology whereby the seasonal factors are revised each quarter to take into account the seasonality exhibited by the latest observation. A more detailed review is conducted annually.
18 From the March quarter 2008, the Survey of Tourist Accommodation collection implemented Autoregressive Integrated Moving Average (ARIMA) modelling techniques for the majority of applicable time series. The revision properties of the seasonally adjusted and trend estimates can be improved by the use of ARIMA modelling. ARIMA modelling relies on the characteristics of the series being analysed to project future period data. The projected values are temporary, intermediate values, that are only used internally to improve the estimation of the seasonal factors. The projected data do not affect the original estimates and are discarded at the end of the seasonal adjustment process.
19 For more information on the details of ARIMA modelling see the feature article 'Use of ARIMA modelling to reduce revisions' in the October 2004 issue of Australian Economic Indicators (cat. no. 1350.0). Any queries regarding the ARIMA modelling should be directed to Time Series Analysis on (02) 6252 6345 or email [email protected].
20 The seasonally adjusted and trend series are updated annually following a review of the seasonal adjustment process. This review provides an opportunity to confirm the extent to which movements are affected by seasonal or irregular influences. As a result, the seasonally adjusted and trend estimates of a number of series are revised.
21 Unreliable seasonal adjustment: In using the seasonally adjusted series, care should be exercised for the following data series: Takings, Australian Capital Territory because of the difficulties associated with reliably estimating the seasonal pattern. This series will be revised during the next annual seasonal adjustment reanalysis.
### Trend estimates
22 Smoothing the seasonally adjusted series reduces the impact of the irregular component of the seasonally adjusted series and creates the trend estimates. The trend estimates are derived by applying a 7-term Henderson moving average to the quarterly seasonally adjusted series. The Henderson moving average used in the middle of the time series is symmetric but, as the end of a time series is approached, asymmetric forms of the symmetric moving average are applied. Unlike the weights of the symmetric 7-term Henderson moving average, the asymmetric weights have been tailored to suit the particular characteristics of individual series.
23 While these techniques enable trend estimates for the latest period to be produced, the process does result in revisions to the trend estimates in recent quarters, particularly as additional original estimates become available. For further information refer to Information Paper: A Guide to Interpreting Time Series - Monitoring Trends (cat. no. 1349.0) available at the ABS web site www.abs.gov.au.
### Confidentialisation of data
24 Under the Census and Statistics Act, when releasing statistics the ABS is required to do this in a manner that is "not likely" (in a legal sense) to enable the identification of a particular person or organisation. A number of techniques are used to do this, including suppression of information. To ensure provider confidentiality in the Survey of Tourist Accommodation, the ABS uses a computerised process known as Disclosure Avoidance Analysis System (DAAS) to confidentialise the entire tourist accommodation dataset each quarter. This process not only ensures that data are suppressed to ensure individual establishments cannot be identified, but also suppresses data in other (consequential) cells to ensure data cannot be derived through deduction from the information available.
### User aggregation of data
25 The aggregation of data by users across time periods should be undertaken with caution, due to the possibility of non-inclusion of confidentialised data (see the above section for more information about confidentialisation). Where one or more cells contributing to a total have been confidentialised (ie, contains the value of n.p.), the resulting aggregated total will be incorrect. However, some broader levels of data may not be affected by confidentialised cells.
26 Where data can be aggregated (ie, no confidentialised cells are included) for calendar and financial year/s purposes, the data items Establishments, Rooms, Persons employed and Bed spaces should not be aggregated. For these items it is recommended that for calendar years, the value of the December quarter is used, and for financial years, the value of the June quarter is used.
27 Any data items that have been derived from other items collected in the survey cannot be aggregated (ie, all those with labels ending in 'rate' or commencing with 'average'). These items must be re-derived based on the aggregation of each of the quarterly items collected in the survey used in the derivation of the rate or average (see Glossary for formulas).
28 Users are cautioned against deriving any non-standard aggregations (eg, aggregation of selected star grading such as 4-star and 5-star; aggregation of selected geographical areas such as capital city areas and balance of state; aggregation of selected activities such as hotels and motels combined). This is because data are confidentialised based on the standard data item structure.
### Effects of rounding
29 Where figures have been rounded, discrepancies may occur between totals and the sum of the component items.
30 Estimates of movement shown in this publication are obtained by taking the difference of unrounded estimates. The movement is then rounded to one decimal place. Therefore where a discrepancy occurs between the reported movement and the difference of the rounded estimates, the reported movement will be more accurate.
### Related publications
31 Other ABS publications and products which may be of interest are outlined below. All publications released from 1998 onwards are available on the ABS web site www.abs.gov.au.
Tourist Accommodation, Australia (cat. no. 8635.0)
Tourism Region Maps and Correspondence Files, Australia (cat. no. 9503.0.55.001) (annual)
Tourist Accommodation, Australia, Expanded Scope Collection (cat. no. 8635.0.55.001) (irregular)
Short-term Visitor Arrivals Estimates, Australia (cat. no. 3401.0.55.001) (issued monthly)
Overseas Arrivals and Departures, Australia (cat. no. 3401.0) (issued monthly)
Australian National Accounts, Tourism Satellite Account (cat. no. 5249.0) (annual)
32 The catalogue of current publications and other products is available from the ABS web site www.abs.gov.au. The ABS also issues release advice on the web site which detail products to be released both in the coming week and the next six months.
### ABS data available on request
33 As well as the statistics included in this publication, the ABS has other relevant data available on request. Inquiries should be made to the National Information and Referral Service on 1300 135 070.
## Glossary
### Show all
#### Average length of stay
Average number of days each guest stayed during the reference period. It is a derived item calculated by dividing the number of guest nights occupied by the number of guest arrivals with the result expressed as a number of days,
\large{ \begin{aligned}\text{Average length of stay(days)}=\frac{Guest \ nights \ occupied}{Guest \ arrivals}\end{aligned}}
#### Average takings per room night available
The takings from accommodation divided by the total number of room nights available for the survey period,
\large{\begin{aligned}\text{Average takings per available room night(\)}=\frac{Takings \ from \ accommodation}{Room \ nights \ available}\end{aligned}}
#### Average takings per room night occupied
The takings from accommodation divided by the total number of room nights occupied for the survey period,
\large{\begin{aligned}\text{Average takings per room night occupied (\)}=\frac{Takings \ from \ accommodation}{Room \ nights \ occupied}\end{aligned}}
#### Bed occupancy rate
Bed occupancy expressed as a percentage of total capacity available during the survey period,
\large{\begin{aligned}\text{Bed occupancy rate (%)}=\frac{Guest \ nights \ occupied}{Guest \ nights \ available} \times 100 \end{aligned}}
#### Bed spaces
Bed spaces normally in place and available to accommodate paying guests during the survey period. Single beds, three-quarter beds and any beds designed to sleep one person are counted as one bed space. Double, queen and king size beds and any beds designed to sleep two people are counted as two bed spaces. Bunk beds have various configurations. If a bunk bed is designed to sleep two guests, it will count as two bed spaces. Any style of bed that is normally used as a bed is included. Fold away beds and sofas permanently made up as beds are included. Cots, divans and any other type of temporary beds not normally used as beds are excluded.
#### Capacity
Capacity is the measure of total accommodation stock available at an establishment to accommodate paying guests on the last day of the survey period. It may be given by various measures such as the maximum number of rooms, units, apartments or suites. Capacity closed temporarily for seasonal reasons is included.
#### Establishments
Hotels and resorts, motels, private hotels, guest houses and serviced apartments within the scope of the survey which operated for any part of the survey period, or which closed temporarily for the quarter for seasonal reasons.
#### Facilities
Establishments may provide a wide variety of facilities to their paying guests. For the purposes of this survey, all establishments within the scope of the survey provide bath/shower and toilet facilities in most of their rooms. Serviced apartments also provide fully self-contained cooking facilities in most rooms/units.
#### Guest arrivals
Paying guests counted only on the first night of their stay at the accommodation establishment during the survey period. Guest arrivals may also be known as ‘check ins’. If the same individual returns for a second stay at the accommodation establishment during the same survey period, the first night of the second stay is regarded as a separate guest arrival.
#### Guest nights available
The total number of bed spaces multiplied by the number of days for which they were available to paying guests during the survey period. For establishments closing (other than for seasonal reasons) or opening during this period, operating periods only are included.
#### Guest nights occupied
The total number of paying guests counted on each night they stayed at the accommodation establishment during the survey period.
#### Hotels and resorts (Hotels)
Establishments with 15 or more rooms which operate a public bar and which provide accommodation on a room/unit/apartment/suite basis rather than by the bed as is the practice of visitor hostels. Most guest rooms are equipped with a bath/shower and toilet but not full cooking facilities (i.e. hot plates and oven/microwave). Hotels and resorts may also include establishments referred to as resort hotel and spa, luxury hotel, apartment hotel, boutique hotel, hotel motel, and commercial hotel. This group of establishments is sometimes abbreviated to 'Hotels' in the text as well as in the table and graph titles in this publication.
#### Motels, private hotels and guest houses (Motels)
Establishments with 15 or more rooms that do not operate a public bar but which provide accommodation on a room/unit/apartment/suite basis rather than by the bed as is the practice of visitor hostels. Most guest rooms are equipped with a bath/shower and toilet but do not have full cooking facilities (i.e. hot plates and oven/microwave). A motel would typically offer guests overnight accommodation and is targeted to the motorist with car parking provided. A private hotel is often a residential hotel that also offers short-term stays. A guest house is typically a personal residence with some accommodation available for paying guests. This group of establishments is sometimes abbreviated to 'Motels' in the text as well as in the table and graph titles in this publication.
#### Occupancy
Occupancy can refer to the total number of nights each room/unit/apartment/suite was occupied during the survey period or the total number of paying guests counted on each night they stayed at the accommodation establishment during the same period. Room occupancy rates and bed occupancy rates are calculated from room nights and guest nights.
#### Paying guest
Guests occupying rooms provided for short-term non-residential accommodation.
#### Persons employed
Persons working at each accommodation establishment during the last pay period ending within the survey period (including working proprietors and those working on other than accommodation activities). Non-salaried workers including volunteers, contractors, and self-employed persons are excluded.
#### Room nights available
The number of rooms/units available multiplied by the number of days for which they were available during the survey period. For establishments closing (other than for seasonal reasons) or opening during this period, operating periods only are included.
#### Room nights occupied
The nights each guest room/unit was occupied by a paying guest during the survey period.
#### Room occupancy rate
Room occupancy expressed as a percentage of total capacity available during the survey period,
\large{\begin{aligned}\text{Room occupancy rate (%)}=\frac{Rooms \ nights \ occupied}{Room \ nights \ available} \times 100 \end{aligned}}
providing that, for establishments closing (other than for seasonal reasons) or opening during the survey period, the denominator of the above expression includes only operating periods.
#### Rooms
Rooms available for accommodating short-term paying guests at each hotel and resort, motel, guest house, and serviced apartment during the survey period. Units, apartments and suites are treated as rooms for these types of establishments.
#### Serviced apartments
Establishments with 15 or more units which mostly comprise self-contained units at the same location, and which are available on a unit/apartment basis to the general public for a minimum of one night. The units should have full cooking facilities (i.e. hot plates and oven/microwave), refrigerator and bath/shower and toilet facilities; all bed linen and towels should be provided, and daily servicing (i.e. cleaning and bed making) must be available through the on-site management, although this service may not necessarily be used.
#### Takings from accommodation (Takings)
Revenue received from the provision of accommodation (excluding revenue received from the provision of meals and other foods and beverages). Since 1 July 2000, takings from accommodation include gross revenue from the provision of accommodation, including GST. In cases where takings from accommodation data cannot be provided inclusive of GST, the amount of GST payable is estimated and the data revised accordingly. Takings from accommodation for each month generally represent the takings received during that month. Where payments are received in advance of, or after the provision of accommodation to guests, the monthly figure for takings from accommodation may not necessarily bear a direct relationship to the number of guests accommodated during the month. Takings from accommodation is sometimes abbreviated as 'Takings' in the text as well as in the table and graph titles in this publication.
| 2021-08-05T17:16:24 |
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|
https://par.nsf.gov/biblio/10314486-infrared-surface-brightness-fluctuation-distances-massive-type-ia-supernova-host-galaxies
|
Infrared Surface Brightness Fluctuation Distances for MASSIVE and Type Ia Supernova Host Galaxies*
Abstract We measured high-quality surface brightness fluctuation (SBF) distances for a sample of 63 massive early-type galaxies using the WFC3/IR camera on the Hubble Space Telescope. The median uncertainty on the SBF distance measurements is 0.085 mag, or 3.9% in distance. Achieving this precision at distances of 50–100 Mpc required significant improvements to the SBF calibration and data analysis procedures for WFC3/IR data. Forty-two of the galaxies are from the MASSIVE Galaxy Survey, a complete sample of massive galaxies within ∼100 Mpc; the SBF distances for these will be used to improve the estimates of the stellar and central supermassive black hole masses in these galaxies. Twenty-four of the galaxies are Type Ia supernova hosts, useful for calibrating SN Ia distances for early-type galaxies and exploring possible systematic trends in the peak luminosities. Our results demonstrate that the SBF method is a powerful and versatile technique for measuring distances to galaxies with evolved stellar populations out to 100 Mpc and constraining the local value of the Hubble constant.
Authors:
; ; ; ; ; ; ; ; ; ; ;
Award ID(s):
Publication Date:
NSF-PAR ID:
10314486
Journal Name:
The Astrophysical Journal Supplement Series
Volume:
255
Issue:
2
ISSN:
0067-0049
We present observations of the dwarf galaxies GALFA Dw3 and GALFA Dw4 with the Advanced Camera for Surveys on the Hubble Space Telescope. These galaxies were initially discovered as optical counterparts to compact Hiclouds in the GALFA survey. Both objects resolve into stellar populations which display old red giant branch (RGB), younger helium-burning, and massive main sequence stars. We use the tip of the RGB method to determine the distance to each galaxy, finding distances of$7.61−0.29+0.28$Mpc and$3.10−0.17+0.16$Mpc, respectively. With these distances we show that both galaxies are extremely isolated, with no other confirmed objects within ∼1.5 Mpc of either dwarf. GALFA Dw4 is also found to be unusually compact for a galaxy of its luminosity. GALFA Dw3 and Dw4 contain Hiiregions with young star clusters and an overall irregular morphology; they show evidence of ongoing star formation through both ultraviolet and Hαobservations and are therefore classified as dwarf irregulars (dIrrs). The star formation histories of these two dwarfs show distinct differences: Dw3 shows signs of a recently ceased episode of active star formation across the entire dwarf, while Dw4 shows some evidence for current star formation in spatially limited Hiiregions. Compact Hisources offermore »
| 2023-02-04T06:16:49 |
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|
https://control.com/textbook/calculus/how-derivatives-and-integrals-relate-to-one-another/
|
# How Derivatives and Integrals Relate to One Another
## Chapter 1 - Calculus in Industrial Process Measurement and Control
First, let us review some of the properties of differentials and derivatives, referencing the expression and graph shown below:
• A differential is an infinitesimal increment of change (difference) in some continuously-changing variable, represented either by a lower-case Roman letter $$d$$ or a lower-case Greek letter “delta” ($$\delta$$). Such a change in time would be represented as $$dt$$; a similar change in temperature as $$dT$$; a similar change in the variable $$x$$ as $$dx$$.
• A derivative is always a quotient of differences: a process of subtraction (to calculate the amount each variable changed) followed by division (to calculate the rate of one change to another change).
• The units of measurement for a derivative reflect this final process of division: one unit divided by some other unit (e.g. gallons per minute, feet per second).
• Geometrically, the derivative of a function is its graphical slope (its “rise over run”).
• When computing the value of a derivative, we must specify a single point along the function where the slope is to be calculated.
• The tangent line matching the slope at that point has a “rise over run” value equal to the derivative of the function at that point.
Next, let us review some of the properties of integrals, referencing the expression and graph shown below:
• An integral is always a sum of products: a process of multiplication (to calculate the product of two variables) followed by addition (to sum those quantities into a whole).
• The units of measurement for an integral reflect this initial process of multiplication: one unit times some other unit (e.g. kilowatt-hours, foot-pounds, volt-seconds).
• When computing the value of an integral, we must specify both the starting and ending points along the function defining the interval of integration ($$a$$ and $$b$$).
• Geometrically, the integral of a function is the graphical area enclosed by the function and the interval boundaries.
• The area enclosed by the function may be thought of as an infinite sum of extremely narrow rectangles, each rectangle having a height equal to one variable ($$y$$) and a width equal to the differential of another variable ($$dx$$).
Just as division and multiplication are inverse mathematical functions (i.e. one “un-does” the other), differentiation and integration are also inverse mathematical functions. The two examples of propane gas flow and mass measurement highlighted in the previous sections illustrates this complementary relationship. We may use differentiation with respect to time to convert a mass measurement ($$m$$) into a mass flow measurement ($$W$$, or $$dm \over dt$$). Conversely, we may use integration with respect to time to convert a mass flow measurement ($$W$$, or $$dm \over dt$$) into a measurement of mass gained or lost ($$\Delta m$$).
Likewise, the common examples of position ($$x$$), velocity ($$v$$), and acceleration ($$a$$) used to illustrate the principle of differentiation are also related to one another by the process of integration. Reviewing the derivative relationships:
$v = {dx \over dt} \hbox{\hskip 30pt Velocity is the derivative of position with respect to time}$
$a = {dv \over dt} \hbox{\hskip 30pt Acceleration is the derivative of velocity with respect to time}$
Now, expressing position and velocity as integrals of velocity and acceleration, respectively11:
$x = \int v \> dt \hbox{\hskip 30pt Position is the integral of velocity with respect to time}$
$v = \int a \> dt \hbox{\hskip 30pt Velocity is the integral of acceleration with respect to time}$
Differentiation and integration may be thought of as processes transforming these quantities into one another. Note the transformation of units with each operation – differentiation always divides while integration always multiplies:
The inverse nature of these two calculus operations is codified in mathematics as the Fundamental Theorem of Calculus, shown here:
${d \over dx} \left[ \int_a^b f(x) \> dx \right] = f(x)$
What this equation tells us is that the derivative of the integral of any continuous function is that original function. In other words, we can take any mathematical function of a variable that we know to be continuous over a certain range – shown here as $$f(x)$$, with the range of integration starting at $$a$$ and ending at $$b$$ – integrate that function over that range, then take the derivative of that result and end up with the original function. By analogy, we can take the square-root of any quantity, then square the result and end up with the original quantity, because these are inverse functions as well.
A feature of this book which may be helpful to your understanding of derivatives, integrals, and their relation to each other is found in an Appendix section (Appendix [animation_calculus_tankfilling] beginning on page ). In this section, a series of illustrations provides a simple form of animation you may “flip” through to view the filling and emptying of a water storage tank, with graphs showing stored volume ($$V$$) and volumetric flow rate ($$Q$$). Since flow rate is the time-derivative of volume ($$Q = {dV \over dt}$$) and volume change is the time-integral of volumetric flow rate ($$\Delta V = \int Q \> dt$$), the animation demonstrates both concepts in action.
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Published under the terms and conditions of the Creative Commons Attribution 4.0 International Public License
| 2020-10-29T20:33:23 |
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|
https://www.usgs.gov/center-news/k-laueas-south-flank-earthquakes-more-common-hurricanes
|
# Kīlauea's south flank earthquakes more common than hurricanes
Release Date:
Early Wednesday morning, as most island residents slept peacefully in the knowledge that we were to be spared by hurricane Flossie, some of us were jolted awake by yet another earthquake. This was a magnitude-4.4 quake beneath the south flank of Kīlauea. A larger earthquake earlier in the week—a magnitude 5.4 on Monday evening—also occurred beneath Kīlauea's south flank.
Kīlauea's south flank earthquakes more common than hurricanes
(Public domain.)
Both of these earthquakes were located at about the same depth (9-10 km; about 6 miles) and at about the same distance south from Kīlauea's east rift zone, but the second quake was about 10 miles west of the first. These earthquakes bracket the east-west extent of the increased activity on the rift zone during the last two months.
Monday's earthquake occurred south of the current eruptive vent, which opened on July 21, in the middle part of the rift zone. Wednesday's earthquake was closer to Kīlauea's summit, centered just south of Pauahi Crater, where magma first forcibly intruded the rift zone in June.
This summer's activity originated way back in late 2003, when the summit area of Kīlauea started to rise and expand, while the eruption at Puu Oo continued unchanged. More magma was being supplied to Kīlauea than could be delivered through the existing plumbing system within the rift zone. The volcano continued to inflate over the next several years, generating many small earthquakes in the process.
In May of this year, there was a renewed surge of seismicity in the summit area. On May 24, several earthquakes occurred along faults that mark the outer boundaries of Kīlauea's caldera. The largest of these was a magnitude 4.7, which was the largest summit area earthquake in the past 50 years. So much magma had accumulated beneath the summit that some serious rock breaking was required to relieve the pressure!
Still the swelling continued, until 02:16 a.m. on Father's Day, June 17th, when magma abruptly started leaving the summit reservoir and intruding the upper east rift zone, near Pauahi. About six hours later, magma migrated farther down the rift and accumulated near Makaopuhi Crater for the next day-and-a-half. By the time the intrusion was over, the rift zone near Makaopuhi had widened by almost a meter (about 3 ft).
Magma supply to Puu Oo was cut off during this event, and lava did not return there until July 2. Even after a new lava lake formed in Puu Oo Crater, the summit continued to inflate, until July 21. Just after midnight, eruptive fissures propagated downrift from the Puu Oo cone, feeding lava flows and perched lava ponds. By early August, the eruption had localized at the lowest fissure, and has been building a perched, open lava channel that feeds aa flows advancing northeast.
Since the opening of the new eruptive fissures on July 21, the summit has been subsiding and contracting as magma moves from the reservoir to the eruption site. Seismicity quieted considerably-until the south flank events this week.
Did all this exciting activity cause this week's earthquakes? As usual, the answer isn't quite that simple. It may be more accurate to say that the intrusion triggered these earthquakes, but didn't exactly "cause" them.
Moderate-to-large earthquakes on the south flank after east rift zone intrusions are fairly common. The most recent example was a magnitude 5.1 in 1997, which occurred several months after an intrusion similar to the Father's Day event. That earthquake originated in exactly the same place as Monday evening's quake.
The areas of Monday's and Wednesday's quakes, however, have also generated numerous earthquakes not associated with intrusions. For example, the 1989 magnitude-6.2 earthquake was also located in almost exactly the same place as Monday's quake.
We also observe steady motion of the south flank towards the sea at about 6 cm (2.4 inches) per year. Obviously, there are forces that cause the south flank to move even in the absence of shallow rift zone intrusions. In addition to the inescapable force of gravity causing seaward slumping, magma accumulating in the deep core of the rift zone may be pushing the south flank seaward.
It is likely that the south flank of Kīlauea, being perpetually under some degree of stress, was already poised for an earthquake. Intrusions, such as the Father's Day sequence of events, may provide the proverbial last straw that triggers the release of at least some of the stress in the form of earthquakes large enough to serve as wake-up calls.
————————————————————————————————————————————————————————————————
### Volcano Activity Update
The July 21 fissure eruption remains active. Of the four original fissure segments, only fissure D-the fissure farthest east-is erupting lava. The lava enters an open channel up to as much as 200 feet across that heads toward the northeast. Prior to last week, the lava stream transitioned into aa about a mile from the fissure. Poorly developed lava tubes beneath the aa carried the lava forward. Last weekend though, just upstream from that transition point, the north wall of the channel failed. Most, if not all, of the lava was diverted into a new aa flow. For the past week, this new flow has been creeping along the north edge of the initial aa flow fed by the fissure.
Prior to the channel diversion, the terminus of the flow had reached up to just over a mile and a half from the fissure. As of this writing (Thursday, August 16), it is not known if the channel diversion has robbed the entire lava supply or if some lava is still making it through to the end of the original aa flow. It is also not known if the lava flow being fed by the diverted channel has regained lost ground and caught up to the terminus of the original flow. Regardless, it does not appear that the lava flow has significantly advanced in the past week.
Though the July 21 fissure eruption has stolen the show, Puu Oo is still alive. Steam and fume obscure the crater most of the time, but occasional glimpses of incandescence are still seen at four separate places on the crater floor and in the West gap. As has been seen in years past, Puu Oo could be acting as temporary storage as lava passes beneath the cone on its way to the erupting fissure.
Mauna Loa is not erupting. One earthquake was located beneath the summit. Extension between locations spanning the summit, indicating inflation, continues at steady, slow rates, which have slowed further since May 2007.
Four earthquakes beneath Hawaii Island and one earthquake beneath Maui were reported felt within the past week. A magnitude-2.2 earthquake occurred at 00:54 a.m. H.s.t. on Friday, August 10, and was located 7 km (4 miles) south-southeast of Keokea, Maui at a depth of 13 km (8 miles). The largest earthquake of the past week, a magnitude-5.4 event, occurred at 7:38 p.m. H.s.t. on Monday, August 13, 7 km (4 miles) south of the Puu Oo crater at a depth of 10 km (6 miles). A magnitude-2.1 earthquake occurred at 1:33 a.m. on Tuesday, August 14, and was located 8 km (5 miles) south of Puu O`o at a depth of 10 km (6 miles). A magnitude-4.4 earthquake occurred at 2:23 a.m. H.s.t. on Wednesday, August 15, 12 km (7 miles) southeast of Kīlauea's summit at a depth of 10 km (6 miles). The final felt earthquake this past week was a magnitude 3.8 event at 3:02 a.m. H.s.t. on Thursday, August 16, located 10 km (6 miles) north of Volcano at a depth of 28 km (17 miles).
| 2020-01-18T23:45:53 |
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|
https://pbn.nauka.gov.pl/pbn-report-web/pages/publication/doi/10.1103/PhysRevLett.119.161101
|
GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
PBN-AR
Instytucja
Centrum Astronomiczne im. Mikołaja Kopernika Polskiej Akademii Nauk
##### Informacje podstawowe
Główny język publikacji
EN
Czasopismo
PHYSICAL REVIEW LETTERS (45pkt w roku publikacji)
ISSN
0031-9007
EISSN
1079-7114
Wydawca
AMER PHYSICAL SOC
DOI
URL
Rok publikacji
2017
Numer zeszytu
16
Strony od-do
161101
Numer tomu
119
Identyfikator DOI
Liczba arkuszy
##### Autorzy
(liczba autorów: 1126)
##### Słowa kluczowe
EN
General Relativity and Quantum Cosmology
Astrophysics - High Energy Astrophysical Phenomena
##### Streszczenia
Język
EN
Treść
On August 17, 2017 at 12∶41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0 ×10<SUP>4</SUP> years . We infer the component masses of the binary to be between 0.86 and 2.26 M<SUB>☉</SUB> , in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17 - 1.60 M<SUB>☉</SUB> , with the total mass of the system 2.7 4<SUB>-0.01</SUB><SUP>+0.04</SUP>M<SUB>☉</SUB> . The source was localized within a sky region of 28 deg<SUP>2</SUP> (90% probability) and had a luminosity distance of 4 0<SUB>-14</SUB><SUP>+8</SUP> Mpc , the closest and most precisely localized gravitational-wave signal yet. The association with the γ -ray burst GRB 170817A, detected by Fermi-GBM 1.7 s after the coalescence, corroborates the hypothesis of a neutron star merger and provides the first direct evidence of a link between these mergers and short γ -ray bursts. Subsequent identification of transient counterparts across the electromagnetic spectrum in the same location further supports the interpretation of this event as a neutron star merger. This unprecedented joint gravitational and electromagnetic observation provides insight into astrophysics, dense matter, gravitation, and cosmology.
##### Inne
System-identifier
R3882
Crossref
###### Cytowania
Liczba prac cytujących tę pracę
Brak danych
###### Referencje
Liczba prac cytowanych przez tę pracę
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| 2020-02-22T10:21:12 |
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https://lammps.sandia.gov/doc/pair_smd_tlsph.html
|
# pair_style smd/tlsph command
## Syntax
pair_style smd/tlsph args
## Examples
pair_style smd/tlsph
## Description
The smd/tlsph style computes particle interactions according to continuum mechanics constitutive laws and a Total-Lagrangian Smooth-Particle Hydrodynamics algorithm.
This pair style is invoked with the following command:
pair_style smd/tlsph
pair_coeff i j *COMMON rho0 E nu Q1 Q2 hg Cp &
*END
Here, i and j denote the LAMMPS particle types for which this pair style is defined. Note that i and j must be equal, i.e., no tlsph cross interactions between different particle types are allowed. In contrast to the usual LAMMPS pair coeff definitions, which are given solely a number of floats and integers, the tlsph pair coeff definition is organized using keywords. These keywords mark the beginning of different sets of parameters for particle properties, material constitutive models, and damage models. The pair coeff line must be terminated with the *END keyword. The use the line continuation operator & is recommended. A typical invocation of the tlsph for a solid body would consist of an equation of state for computing the pressure (the diagonal components of the stress tensor), and a material model to compute shear stresses (the off-diagonal components of the stress tensor). Damage and failure models can also be added.
Please see the SMD user guide for a complete listing of the possible keywords and material models.
Mixing, shift, table, tail correction, restart, rRESPA info:
No mixing is performed automatically. Currently, no part of USER-SMD supports restarting nor minimization. rRESPA does not apply to this pair style.
## Restrictions
This fix is part of the USER-SMD package. It is only enabled if LAMMPS was built with that package. See the Build package doc page for more info.
| 2019-08-18T01:10:54 |
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|
http://gams.cam.nist.gov/16.26
|
# §16.26 Approximations
For discussions of the approximation of generalized hypergeometric functions and the Meijer $G$-function in terms of polynomials, rational functions, and Chebyshev polynomials see Luke (1975, §§5.12 - 5.13) and Luke (1977b, Chapters 1 and 9).
| 2017-04-28T04:23:14 |
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|
https://indico.fnal.gov/event/19348/contributions/186317/
|
Indico search will be reestablished in the next version upgrade of the software: https://getindico.io/roadmap/
Neutrino 2020
June 22, 2020 to July 2, 2020
US/Central timezone
Measurement of the Leptonic CP Violation Phase With a New Parameterization Using T2K Neutrino Oscillation Data
Not scheduled
10m
Poster
Speaker
Mr Xingyu Zhao (ETH Zurich)
Description
The T2K experiment is designed to measure neutrino oscillations with a baseline 295 km
and peak neutrino beam energy E = 0.6 GeV. One of the main goals of the experiment is
to obtain the most precise confidence interval for the oscillation parameter: leptonic CP-violation
phase $\delta_{CP}$ in the PMNS framework. This is achieved by performing a joint and constrained fit, using data from both the neutrino and antineutrino modes.
The CP-violation phase enters in the actual oscillation probabilities as two
separate terms, which contribute differently to the oscillation probabilities, but which are internally constrained to satisfy unitarity.
In the work presented, the T2K data has been fitted with a reparametrized PMNS framework, in which the
two $\delta_{CP}$ terms are treated separately. Such an approach allows
testing whether the T2K neutrino oscillation data allows for any significant non-standard PMNS behaviour
in terms of $\delta_{CP}$.
Mini-abstract
A reparametrized PMNS framework to measure $\delta_{CP}$ using T2K neutrino oscillation data
Experiment/Collaboration T2K Experiment
Primary author
Mr Xingyu Zhao (ETH Zurich)
| 2021-12-05T11:28:54 |
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|
http://mathonline.wikidot.com/the-divergence-and-curl-of-a-vector-field-in-two-dimensions
|
The Divergence and Curl of a Vector Field In Two Dimensions
# The Divergence and Curl of a Vector Field In Two Dimensions
From The Divergence of a Vector Field and The Curl of a Vector Field pages we gave formulas for the divergence and for the curl of a vector field $\mathbf{F}(x, y, z) = P(x, y, z) \vec{i} + Q(x, y, z) \vec{j} + R(x, y, z) \vec{k}$ on $\mathbb{R}^3$ given by the following formulas:
(1)
\begin{align} \quad \mathrm{div}( \mathbf{F}) = \nabla \cdot \mathbf{F} = \frac{\partial P}{\partial x} + \frac{\partial Q}{\partial y} + \frac{\partial R}{\partial z} \end{align}
(2)
\begin{align} \quad \mathrm{curl} ( \mathbf{F} ) = \nabla \times \mathbf{F} = \left ( \frac{\partial R}{\partial y} - \frac{\partial Q}{\partial z} \right ) \vec{i} + \left( \frac{\partial P}{\partial z} - \frac{\partial R}{\partial x}\right ) \vec{j} + \left ( \frac{\partial Q}{\partial x} - \frac{\partial P}{\partial y} \right ) \vec{k} \end{align}
Now suppose that $\mathbf{F}(x, y) = P(x, y) \vec{i} + Q(x, y) \vec{j}$ is a vector field in $\mathbb{R}^2$. Then we define the divergence and curl of $\mathbb{F}$ as follows:
Definition: If $\mathbf{F}(x, y) = P(x, y)\vec{i} + Q(x, y) \vec{j}$ and $\frac{\partial P}{\partial x}$ and $\frac{\partial Q}{\partial y}$ both exist then the Divergence of $\mathbf{F}$ is the scalar field given by $\mathrm{div} (\mathbf{F}) = \frac{\partial P}{\partial x} + \frac{\partial Q}{\partial y}$.
Definition: If $\mathbf{F}(x, y) = P(x,y)\vec{i} + Q(x, y) \vec{j}$ and $\frac{\partial Q}{\partial x}$ and $\frac{\partial P}{\partial y}$ both existence then the Curl of $\mathbf{F}$ is the vector field given by $\mathrm{curl} (\mathbf{F}) = \left ( \frac{\partial Q}{\partial x} - \frac{\partial P}{\partial y} \right ) \vec{k}$.
It is important to note that the curl of $\mathbf{F}$ exists in three dimensional space despite $\mathbf{F}$ be a vector field on $\mathbb{R}^2$.
## Example 1
Find the divergence of the vector field $\mathbf{F}(x, y) = 2xy \vec{i} + 3 \cos y \vec{j}$.
We can apply the formula above directly to get that:
(3)
\begin{align} \quad \mathrm{div} (\mathbf{F}) = \frac{\partial}{\partial x} (2xy) + \frac{\partial}{\partial y} (3 \cos y) = 2y - 3 \sin y \end{align}
## Example 2
Find the divergence of the vector field $\mathbf{F}(x, y) = e^x y^2 \vec{i} + (x + 2y) \vec{j}$.
We can apply the formula above directly to get that:
(4)
\begin{align} \quad \mathrm{div} (\mathbf{F}) = \frac{\partial}{\partial x} (e^x y^2) + \frac{\partial}{\partial y} (x + 2y) = e^x y^2 + 2 \end{align}
## Example 3
Find the curl of the vector field $\mathbf{F}(x, y) = 2xy \vec{i} + 3 \cos y \vec{j}$.
We can apply the formula above directly to get that:
(5)
\begin{align} \quad \mathrm{curl} (\mathbf{F}) = \left ( \frac{\partial}{\partial x} (3 \cos y) - \frac{\partial}{\partial y} (2xy) \right ) \vec{k} \\ \quad \mathrm{curl} (\mathbf{F}) = -2x \vec{k} \end{align}
## Example 4
Find the curl of the vector field $\mathbf{F}(x, y) = e^x y^2 \vec{i} + (x + 2y) \vec{j}$.
We can apply the formula above directly to get that:
(6)
\begin{align} \quad \mathrm{curl} (\mathbf{F}) = \left ( \frac{\partial}{\partial x} (x + 2y) - \frac{\partial}{\partial y} (e^x y^2) \right ) \vec{k} \\ \quad \mathrm{curl} (\mathbf{F}) = (1 - 2e^xy) \vec{k} \end{align}
Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License
| 2017-12-13T05:24:21 |
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|
https://par.nsf.gov/biblio/10287447-tdcosmo-iv-hierarchical-time-delay-cosmography-joint-inference-hubble-constant-galaxy-density-profiles
|
TDCOSMO: IV. Hierarchical time-delay cosmography – joint inference of the Hubble constant and galaxy density profiles
The H0LiCOW collaboration inferred via strong gravitational lensing time delays a Hubble constant value of H 0 = 73.3 −1.8 +1.7 km s −1 Mpc −1 , describing deflector mass density profiles by either a power-law or stars (constant mass-to-light ratio) plus standard dark matter halos. The mass-sheet transform (MST) that leaves the lensing observables unchanged is considered the dominant source of residual uncertainty in H 0 . We quantify any potential effect of the MST with a flexible family of mass models, which directly encodes it, and they are hence maximally degenerate with H 0 . Our calculation is based on a new hierarchical Bayesian approach in which the MST is only constrained by stellar kinematics. The approach is validated on mock lenses, which are generated from hydrodynamic simulations. We first applied the inference to the TDCOSMO sample of seven lenses, six of which are from H0LiCOW, and measured H 0 = 74.5 −6.1 +5.6 km s −1 Mpc −1 . Secondly, in order to further constrain the deflector mass density profiles, we added imaging and spectroscopy for a set of 33 strong gravitational lenses from the Sloan Lens ACS (SLACS) sample. For nine of the 33 SLAC lenses, more »
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
Award ID(s):
Publication Date:
NSF-PAR ID:
10287447
Journal Name:
Astronomy & Astrophysics
Volume:
643
Page Range or eLocation-ID:
A165
ISSN:
0004-6361
5. ABSTRACT Core formation and runaway core collapse in models with self-interacting dark matter (SIDM) significantly alter the central density profiles of collapsed haloes. Using a forward modelling inference framework with simulated data-sets, we demonstrate that flux ratios in quadruple image strong gravitational lenses can detect the unique structural properties of SIDM haloes, and statistically constrain the amplitude and velocity dependence of the interaction cross-section in haloes with masses between 106 and 1010 M⊙. Measurements on these scales probe self-interactions at velocities below $30 \ \rm {km} \ \rm {s^{-1}}$, a relatively unexplored regime of parameter space, complimenting constraints at highermore »
| 2022-06-28T03:46:43 |
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