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http://math.stackexchange.com/questions/215315/noetherian-ring-and-primary-decomposition-result
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# Noetherian ring and primary decomposition result
I'm struggling with the following problem and I would appreciate some help if possible
Let $R$ be Noetherian and let $I,J$ be ideals. Define $(I:J^{\infty}) = \bigcup_{n}(I:J^{n})$.
(a) If $Q$ is primary, prove that $(Q:J^{\infty}) = Q$ for any $J \subset R$ with $J$ not contained in the radical of $Q$.
(b) If $P$ is prime and $I = Q_{1} \cap \ldots \cap Q_{k}$ is a finite intersection of primary ideals, then show that $(I : P^{\infty})$ is the intersections of the $Q_{i}$ for which $P \not \subset P_{i}$.
Thank you!
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(a) If $aJ^n\subseteq Q$, $Q$ primary and $J\nsubseteq \sqrt{Q}$ (therefore $J^n\nsubseteq \sqrt{Q}$), then... – user26857 Oct 17 '12 at 9:11
(b) Apply (a) using that $(Q_1\cap\cdots\cap Q_k:P^{\infty})=(Q_1:P^{\infty})\cap\cdots\cap(Q_k:P^{\infty})$. – user26857 Oct 17 '12 at 9:20
Thanks a lot! I had (b), but I don't know why I couldn't see a) :)); this is what happens when you don't sleep enough – Dquik Oct 18 '12 at 1:46
An alternative definition of primary ideals is the following: $Q$ is primary iff for every ideals $I,J$ with $IJ\subseteq Q$ we have $I\subseteq Q$ or $J\subseteq\sqrt{Q}$ (or viceversa). IN my answer to (a) take $I=(a)$. – user26857 Oct 18 '12 at 8:05
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http://cs.stackexchange.com/users/1636/luke-mathieson
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# Luke Mathieson
less info
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bio website comp.mq.edu.au/~lmathies location Australia age 34 member for 2 years, 9 months seen 1 hour ago profile views 348
I'm a postdoc working on a big mess of different things, but all related by the use of parameterized complexity to help deal with hard problems. Mostly they're graph problems, but they come from all over the place. I'm also very interested in the structure of and relationships between complexity classes, especially in how they capture different, independent aspects of computation and its complexity.
21 If P = NP, why wouldn't $\emptyset$ and $\Sigma^*$ be NP-complete? 19 Union of regular languages that is not regular 18 Is a push-down automaton with two stacks equivalent to a turing machine? 14 Prove that every two longest paths have at least one vertex in common 13 Does the proof of undecidability of the Halting Problem cheat by reversing results?
# 8,385 Reputation
+25 What is the name of this size method calculating the size of a node? +35 How do I show that a DFA accepts only one word? +25 Construction of a counter automaton for the complement of the palindromes +15 Richard Karp's 21 NP-Hard problems, the meaning of his research?
# 0 Questions
This user has not asked any questions
# 102 Tags
202 complexity-theory × 46 90 formal-languages × 22 109 np-complete × 24 83 terminology × 15 103 reductions × 23 81 graph-theory × 20 100 algorithms × 21 77 turing-machines × 22 91 automata × 21 76 computability × 13
# 11 Accounts
Computer Science 8,385 rep 31443 Academia 1,571 rep 617 Mathematics 990 rep 612 Theoretical Computer Science 863 rep 516 MathOverflow 191 rep 15
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http://deletemalware.blogspot.com/2011/09/remove-chit-chat-uninstall-guide.html
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Your computer is infected with malicious software? Do you have pop-ups on your PC?
If so, search this blog for removal instructions or browse computer threats by category.
## Monday, September 5, 2011
### Remove Chit Chat (Uninstall Guide)
Chit Chat is a rather interesting software that allows you to chat with your Facebook friends directly from your Desktop. You don't have to login to Facebook, it's an instant messaging application, just like the Windows Live Messenger or Yahoo! IM. Although, I don't do online chat very often, but I get the idea and I think Chit Chat may be very useful indeed. However, there's one thing you should know about this software - it comes bundled with Relevant knowledge and it also installs Chit Chat Toolbar in Internet Explorer and Mozilla Firefox.
Relevant knowledge is classified as spyware, that's why Chit Chat is also detected as spyware/adware by some antivirus software vendors. It also drops Spigot search settings component and Application Updater background process tool on your computer. You may choose not to install Relevant knowledge, however, there's another thing to worry about:
depending on options and usage, application may include automatic applications updates, a network error assistant, or transmit personally identifiable information.
That doesn't sound right, especially the statement about personally identifiable information. It's not clear whether this statement applies to Relevant knowledge components or the Chit Chat program itself.
And here's the Relevant knowledge end user license agreement:
We are not saying that you shouldn't use Chit Chat, but you should follow the installation process very carefully. It is also worth mentioning that if you want to completely remove Chit Chat from your computer, you have to remove Chit Chat for Facebook and Chit Chat Toolbar. Many users point out that they removed the Chit Chat application but the toolbar and search settings remains the same, meaning they were not removed from the computer. To remove ChitChat from your computer, please follow the removal instructions below. If you have any questions, please leave a comment below. Good luck and be safe online!
Chit Chat removal instructions:
1. Go to the Start Menu. Select Control PanelAdd/Remove Programs.
If you are using Windows Vista or Windows 7, select Control PanelUninstall a Program.
2. Search for Chit Chat for Facebook in the list. Select the program and click Remove button.
If you are using Windows Vista/7, click Uninstall up near the top of that window.
3. Search for Chit Chat Toolbar in the list. Select the program and click Remove button.
If you are using Windows Vista/7, click Uninstall up near the top of that window.
Remove Chit Chat Toolbar in Internet Explorer:
1. Open Internet Explorer. Go to ToolsManage Add-ons.
2. Select Toolbars and Extensions. Uninstall everything related to Spigot, Inc. and Chit Chat.
Remove Chit Chat Toolbar in Mozilla Firefox:
1. Open Mozilla Firefox. Go to ToolsAdd-ons.
2. Select Extensions. Choose Chit Chat Toolbar and Widgi Toolbar Platform and click Uninstall button.
Associated Chit Chat files and registry values:
Files:
• C:\Program Files\Chit Chat For Facebook
• C:\Program Files\Chit Chat For Facebook\Emoticons
• C:\Program Files\Chit Chat For Facebook\Langs
• C:\Program Files\Chit Chat For Facebook\Sounds
• C:\Program Files\Chit Chat For Facebook\CCFFBPlugin.dll
• C:\Program Files\Chit Chat For Facebook\emot.bmp
• C:\Program Files\Chit Chat For Facebook\skin.skn
• C:\Program Files\Chit Chat For Facebook\unins000.dat
• C:\Program Files\Chit Chat For Facebook\unins000.exe
• C:\Program Files\Chit Chat For Facebook\Updater.exe
• C:\Program Files\Chit Chat Toolbar
• C:\Program Files\Chit Chat Toolbar\FF
• C:\Program Files\Chit Chat Toolbar\IE
• C:\Program Files\Chit Chat Toolbar\Res
• C:\Program Files\Chit Chat Toolbar\WidgiHelper.exe
• C:\Program Files\Common Files\Spigot\Search Settings\SearchSettings.exe
• C:\Program Files\Common Files\Spigot\wtxpcomr
• C:\Program Files\Application Updater\ApplicationUpdater.exe
Registry values:
• HKEY_CURRENT_USER\Software\AppDataLow\Software\Chit Chat
• HKEY_CURRENT_USER\Software\Facebook Chat Client
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run "Chit Chat for Facebook"
• HKEY_LOCAL_MACHINE\SOFTWARE\Chit Chat
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Toolbar "Chit Chat Toolbar"
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https://www.groundai.com/project/phase-entanglement-complementarity-with-time-energy-uncertainty/
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Phase-Entanglement Complementarity with Time-Energy Uncertainty
# Phase-Entanglement Complementarity with Time-Energy Uncertainty
Fu-Lin Zhang Department of Physics, School of Science, Tianjin University, Tianjin 300072, P. R. China Mai-Lin Liang Department of Physics, School of Science, Tianjin University, Tianjin 300072, P. R. China
July 15, 2019
###### Abstract
We present a unified view of the Berry phase of a quantum system and its entanglement with surroundings. The former reflects the nonseparability between a system and a classical environment as the latter for a quantum environment, and the concept of geometric time-energy uncertainty can be adopted as a signature of the nonseparability. Based on this viewpoint, we study their relationship in the quantum-classical transition of the environment, with the aid of a spin-half particle (qubit) model exposed to a quantum-classical hybrid field. In the quantum-classical transition, the Berry phase has a similar connection with the time-energy uncertainty as the case with only a classical field, whereas the geometric phase for the mixed state of the qubit exhibits a complementary relationship with the entanglement. Namely, for a fixed time-energy uncertainty, the entanglement is gradually replaced by the mixed geometric phase as the quantum field vanishes. And the mixed geometric phase becomes the Berry phase in the classical limit. The same results can be draw out from a displaced harmonic oscillator model.
###### pacs:
03.65.Vf; 03.65.Ud
## I Introduction
A quantum system always need to be isolated from its surroundings, which is referred to an open quantum system. Otherwise, we would have to treat the system and the rest of the universe Berry (1984) as a whole. An significant obstacle to this separation is the entanglement Horodecki et al. (2009) between the open system and its environment caused by their quantum nature. The system is exactly described by its reduced density matrix defined as the partial trace of a global state over the Hilbert space of environment. In an ideal case, the decoherence of an open system due to entanglement with its environment is negligible. The effects of the environment represents as parameters, or say classical fields, which are time-dependent in most cases, in the local Hamiltonian of the open system. If the field is slowly altered, the open system will behave like a closed one, namely staying adiabatically in an instantaneous eigenstate of the time-dependent Hamiltonian. The difference is that the open system undergoing a cyclic adiabatic evolution gains a Berry phase Berry (1984). In Berry’s original paper Berry (1984), the phase is said to be geometric because it results from the geometric properties of the parameter space of the local Hamiltonian. In other words, it depends on the properties of the external field in evolutionary process, and thus reveals a nonseparable relation between the system and environment.
In the two aforementioned cases, the nonseparability between a system and an environment exhibits either entanglement or Berry phase as the environment is either quantum or classical. This naturally leads to an interesting question: What is their relationship in the quantum-classical transition of the environment? To answer this question, we introduce a model of a spin-half particle (qubit) coupled to an adiabatically rotating quantum-classical hybrid field. And before that, pointed out that the Berry phase is caused by a neglected Hamiltonian and accompanied by a geometric time-energy uncertainty Anandan and Aharonov (1990); Anandan (1991); Uhlmann (1992). This uncertainty is shown to be a signature of the total nonseparability between the system and the quantum-classical hybrid field. Because of the entanglement between the principal qubit and the field, the original definition of the Berry phase is no longer applicable. We study its two extensions, one of which is presented in this work based on the neglected Hamiltonian and the other is the geometric phase for mixed state Sjöqvist et al. (2000); Singh et al. (2003); Tong et al. (2004). In this work, we call the former the Berry phase and the latter the mixed geometric phase. When the classical part of the field vanishes, one can find the Berry phase leads to the definition in the works of vacuum induced Berry phase Fuentes-Guridi et al. (2002); Liu et al. (2010, 2011); Larson (2012) in the Jaynes-Cummings (JC) model Jaynes and Cummings (1963), where they devise the phase with the aid of a phase shift operator. In the quantum-classical transition of external field and for a fixed time-energy uncertainty, the mixed geometric phase replaces the entanglement gradually, and becomes the Berry phase in the classical limit. This shows a complementary relationship between the mixed geometric phase and the entanglement to reflect the nonseparability.
## Ii Neglected Hamiltonian
Before introducing our model, we first carefully examine the connection between the Berry phase of an open system and its nonseparability with a classical environment. The connection will become apparent if we consider the Berry phase as the adiabatic limit of the Aharonov-Anandan (AA) phase Aharonov and Anandan (1987); Zeng and Lei (1995, 1996). The latter is an extension of the Berry phase without adiabatic approximation. It has been shown that only for a nonstationary state after a cyclic evolution might the AA phase appear Zeng and Lei (1995). That is, if an open quantum system stays in an instantaneous eigenstate of its Hamiltonian and acquires an AA phase after a cyclic evolution, there should exist a Hamiltonian which is neglected but affects the system in addition to , and Berry (2009). Therefore, the uncertainty in energy when the system is isolated from its environment causes the AA phase. In the adiabatic limit, , the expectation value of the Hamiltonian becomes the instantaneous eigenvalue of , and the AA phase returns the Berry phase. The Berry phase comes from the fact that even the uncertainty of energy tends to zero in the adiabatic limit, its effect in a cyclic evolution is finite and nonzero. The accumulating result of the uncertanty of energy can be represented as the geometric quantum uncertainty relation Anandan and Aharonov (1990); Anandan (1991); Uhlmann (1992)
S=2∫τ0ΔEdt, (1)
where is the energy fluctuation, defined by
ΔE2=⟨ψ|H2|ψ⟩−⟨ψ|H|ψ⟩2. (2)
It is the distance that the system traverses during its evolution in the projective Hilbert space measured by Fubini-Study metric Anandan and Aharonov (1990). In the following section, we will extend the Berry phase to a system in a quantum-classical hybrid field with the aid of the neglected Hamiltonian, and show the connection between the time-energy uncertainty and its entanglement with the field.
## Iii Qubit Model
Let us now consider the model of a qubit coupled to a rotating quantum-classical hybrid field with the Hamiltonian
H0=−μJ⋅σ−B⋅σ (3)
where are the Pauli operators of the qubit, is the classical part of the field, and denotes the quantum part with being the angular momentum operators of a spin- particle. Experimental realization of the interaction between two spins and observation of the Berry phase for such a system is feasible by current technology Jones et al. (2000); Du et al. (2003). In the frame of quantum optics, the physical meaning of the pure quantum term can be easily understood if we consider the spin operator as the Schwinger representation Fuentes-Guridi et al. (2002) of two modes of a quantized optical field. The Hamiltonian denotes a interacting process between the two modes of optical field and a two level system conserving the total photon number. The whole Hamiltonian (3) could also be regarded as a semiclassical spin star model Calvani et al. (2013a, b); Richter and Voigt (1994); Deng and Fang (2008). As shown in Fig. 1, the system qubit interacts with two Heisenberg chains, i.e. two sets of environmental spins. One of the chains has a total spin , and the other is treated as a classical field as its entanglement with the system qubit is negligible Calvani et al. (2013a, b). The quantum-classical transition of the environment can be shown by tuning the parameter from infinity to zero. Thus the experimental realization of the Hamiltonian (3) provides a simulation of the crossover from a quantum to a classical environment.
Classical Field.– For the simplest case in the absence of quantum field, where , we can treat the principal qubit in the space of itself. The instantaneous eigenstates of corresponding to the eigenvalues are
|ψ+⟩=U(t)|↑⟩, |ψ−⟩=U(t)|↓⟩, (4)
with . To keep the system in the eigenstates , the neglected Hamiltonian should be , and the coefficients . After a period , the total phases are determined by the eigenvalues and the property of the spin-half rotation operation. For the dynamic phase, which is defined by Aharonov and Anandan (1987), we get Hence the Berry phase, as the AA phase in the limit of , can be written as
γ±=∓π(1−cosθ). (5)
They equal the half of the solid angle subtended by the path followed by in the parameter space, and the sign depends on whether the spin was aligned or against the direction of the field. Although the fluctuation of energy defined by (2) approaches zero in the adiabatic limit, the time-energy uncertainty (1) in a period is a constant independent of the frequency as
S±=2πsinθ. (6)
which is nothing but the shortest perimeter surrounding the solid angle in an unit sphere. In this work, we confine ourselves to the case of rotating fields not only for simplicity but also to gain as large the geometric phases as possible under a fixed time-energy uncertainty.
Furthermore, if we consider the geometric phase for noncyclic evolution Samuel and Bhandari (1988) and require corresponding to a reversal of the interference fringes, we can easily obtain a time-energy uncertainty relation in the present model not (a)
⟨ΔE⟩Δt≥h2, (7)
where is the time-averaged uncertainty in energy during the time to gain the geometric phase and is the Planck constant. Equality in (7) holds when the classical field is perpendicular to z axis, i.e. .
Quantum-Classical Hybrid Field.– We will now derive the results for the full Hamiltonian (3). One can diagonalize the Hamiltonian in the subspace of , where is the eigenvector of with and In the unitary transformation, a term is introduced to eliminate the influence of the phase brought by a odd not (b). The instantaneous eigenstates of corresponding to eigenvalues are
|ψ+m⟩=U(t)(cosαm2|m⟩|↑⟩+sinαm2|m+1⟩|↓⟩), |ψ−m⟩=U(t)(sinαm2|m⟩|↑⟩−cosαm2|m+1⟩|↓⟩), (8)
with . Here, the values of index range from to . For or , only two states and are physically possible. They are direct products of two spin-coherent states aligned or against the classical field, and the states of spin- are the closest to the classical states Layton et al. (1990). The concurrence Wootters (1998) of states (III) can be written as
C=sinαm (9)
which is the degree of entanglement between the system qubit and its external field.
In the case of the classical field discussed above, the dynamics of the field is not described by the Hamiltonian (3), but is considered as a time-dependent variable. A quantum field cannot be treated in this way anymore, as its state can be influenced by the interaction with the principal qubit. We have to take into account a Hamiltonian driving the quantum field to rotate with the same frequency as the classical field. The most natural choice of the Hamiltonian is . Staying in the instantaneous eigenstates (III) requires the whole system to satisfy the Schrödinger equation
i|˙Ψ±m⟩=(H0+Hj+HΔ)|Ψ±m⟩, (10)
with . Consequently, the neglected Hamiltonian can be found as , and the coefficients . After a period, the total phase is and the dynamic phase is with . Hence we obtain the Berry phase
γq = π(1−cosθcosαm) (11) = π(1−cosθ)+π(1−cosαm)cosθ,
where we omit the sign for clarity. The second term in (11) shows a correction in Berry phase aroused by the quantum part of the field. We call this term quantum field induced Berry phase (QBP), as it is caused by quantum fluctuation and entanglement. In addition, when the classical field vanishes, one can choose due to the symmetry of the Hamiltonian (3) and find the QBP has the same physical meaning as the vacuum induced Berry phase Fuentes-Guridi et al. (2002); Liu et al. (2010, 2011); Larson (2012). A remarkable quantum nature of QBP can be understood by its sharp contrast to the classical one. Namely, the Berry phase is robust against the perturbations by classical environment, particularly is invariant under a changing of the strength of the field. But it is sensitive to the quantum perturbation even though the polarization direction of the spin- particle in the eigenstates remains parallel to the classical field. From the form of QBP in (11) one can surmise it revelent to a solid angle in a space corresponding to the quantum fluctuation of spin-. The QBP reaches its maximum for the most entangled states with or and vanishes for the two separable eigenstates and . And in the former case the states give rise to the maximum dispersion for square of the spin angular momentum, and the latter two states lead to the minimum Layton et al. (1990).
For further analysis of the physical meaning of QBP and the whole Berry phase in (11) we calculate the geometric time-uncertainty relation (1) during a period of rotation . Substituting the expressions of and into (1) leads to
Sq=2π√1−cos2θcos2αm. (12)
Similar to QBP, it is increased by the entanglement between the qubit and field. It is interesting to note that if one defines an angle , there also exists a relationship of solid angle and perimeter between and as the case of the classical field. That is, the classical part and quantum part of the external field parallel to each other behave as an effective classical field in another direction. This deflection caused by the fluctuation of the quantum field is most visible when , where only the quantum field contributes to and , and vanishes for with the classical filed making the most contribution. Moreover, for a fixed value of geometric phase , the inequality (7) still holds for the qubit system with a quantum-classical hybrid field. And the entanglement between the principal qubit and its external field reduces the value of for a given .
In the above discussion about QBP, we treat the system qubit and the quantum field as a composite system when we consider their evolution. We actually remove terms irrelevant to the qubit in the total phase of the whole system and obtain the Berry phase (11). That is, the Berry phase (11) depends on the evolution of the quantum field entangled with the qubit. To study the phase determined only by the geometry of the path of the qubit, we derive the time-dependent mixed state
ρ=sin2αm2|ψ+⟩⟨ψ+|+cos2αm2|ψ−⟩⟨ψ−|, (13)
by tracing out the quantum filed in the eigenstates (III), where is defined in (4). Here, we only give the case for the pure state , the mixed geometric phase for can be easily obtained by changing into . We can calculate the mixed geometric phase by using the definition with a kinematic description Sjöqvist et al. (2000); Singh et al. (2003); Tong et al. (2004) and get
γmix = arg(sin2αm2eiγ++cos2αm2eiγ−) (14) = arctan(cosαmtanγ−),
where are the Berry phases (5) resulting from the classical field. The phase is manifestly gauge invariant and can be experimentally tested in interferometry.
Let us give a further discussion about the relationship among these quantities related to the nonseparability between the system and the external field. For a fixed value of , , and the entanglement widens their gaps. They are equal to the Berry phase for a separable eigenstate. It is important to note that the time-energy uncertainty leads to an upper bound of the entanglement . The equality holds when the mixed geometric phase vanishes. These reveal a complementary relationship between the mixed geometric phase and the entanglement to reflect the nonseparability between the system and the external field, while and can be considered to be their sum. For a fixed amount of , the entanglement is gradually replaced by the geometric phase in the quantum-classical transition of external field, and becomes the Berry phase when the quantum field vanishes. In a figurative sense, Berry phase is semiclassical entanglement between a quantum system and a classical environment.
## Iv Harmonic Oscillator
We also study a displaced harmonic oscillator which is another canonical example of the Berry phase Chaturvedi et al. (1987) to verify our above discussions. Here we add a qubit as the part of the its environment, which is described in terms of the Pauli operators . Suppose the qubit-oscillator interaction is characterized by a JC term Jaynes and Cummings (1963), we get
H0=νb†b+g(σ−b†+σ+b), (15)
where are displaced creation and annihilation operators with the frequency , is the coupling constant. We take and to be slowly rotating parameters. One can find its instantaneous eigenstates in the subspace , where , and satisfies . The instantaneous eigenstates with eigenvalues are derived as
|ψ+n⟩=V(t)(cosαn2|n⟩|↑⟩−sinαn2|n+1⟩|↓⟩), |ψ−n⟩=V(t)(sinαn2|n⟩|↑⟩+cosαn2|n+1⟩|↓⟩), (16)
where . The concurrence of states is
Ch=sinαn, (17)
which is zero for the state , corresponding to the eigenstate in (IV) with . We also choose a Hamiltonian to drive the rotation of the qubit with the frequency of , which is . The neglected Hamiltonian in this case is . Follow the same steps of the qubit case in the above section, we obtain the time-energy uncertainty
Sqh=2π√4(2n+1)|β|2+sin2αn, (18)
the Berry phase
γqh=2π|β|2±π(1−cosαn), (19)
and the mixed geometric phase
γmixh=2π|β|2. (20)
Here, both the phases are defined modulo . Obviously there exist an entanglement induced term in each of the expression of the time-energy uncertainty and the Berry phase. And the entanglement and the mixed geometric phase are complementary for a fixed value of .
## V Summary
In this work, we present a viewpoint of the Berry phase that it reflects the nonseparability between an open system and its classical environment just like the entanglement between a system and a quantum environment. This unified view of the two concepts inspires us to explore their properties and connection in the quantum-classical transition of the environment. The viewpoint is supported by the fact that the Berry phase can be considered as the effect of a neglected Hamiltonian which affects the system but has no effect on the eigenvalues and eigenstates in the adiabatic limit. This understanding can be obtained by checking the relation between the Berry phase and the AA phase, and provides an approach to extend the Berry phase to the system in a quantum-classical hybird environment. In addition, the geometric time-energy uncertainty as an accumulating result of the neglected Hamiltonian in a cyclic evolution is found to be a signature of the nonseparability not only for a classical environment but also for a quantum-classical hybird one.
Based on foregoing considerations we investigate a qubit under an adiabatically rotating quantum-classical hybrid field. The entanglement between the principal qubit and the field introduces a correction to the time-energy uncertainty and a corresponding effect on the Berry phase. For a fixed time-energy uncertainty, the entanglement is gradually replaced by the mixed geometric phase, determined solely by the geometry of the the qubit, in the quantum-classical transition of external field. That is, the geometric phase and entanglement have complementary relationship to reflect the nonseparability between the system and the external field. We also make similar calculations for a model of displaced harmonic oscillator to verify these conclusions, in which a qubit acts as the quantum part of the field.
We have been very careful to introduce a quantum part of the environment in our models without giving up the conditions of adiabaticity and cyclicity in Berry’s original definition of geometric phase. These models allow us to treat the geometric phases and quantum entanglement uniformly. We believe that, by removing the restrictions in this work, one may uncover more general connections among geometric aspects of quantum mechanics and different quantum correlations Modi et al. (2010).
###### Acknowledgements.
The idea was initiated in our discussions with Wu-Sheng Dai, Mi Xie and Da-Bao Yang. We are very indebted to Sir Michael Berry for his remarks and encouragement. F.L.Z. also thanks Jing-Ling Chen, Mang Feng, Paola Verrucchi, and Kamal Berrada for their valuable comments. This work was supported by NSF of China (Grant No. 11105097).
## References
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• Singh et al. (2003) K. Singh, D. M. Tong, K. Basu, J. L. Chen, and J. F. Du, Phys. Rev. A 67, 032106 (2003).
• Tong et al. (2004) D. M. Tong, E. Sjöqvist, L. C. Kwek, and C. H. Oh, Phys. Rev. Lett. 93, 080405 (2004).
• Fuentes-Guridi et al. (2002) I. Fuentes-Guridi, A. Carollo, S. Bose, and V. Vedral, Phys. Rev. Lett. 89, 220404 (2002).
• Liu et al. (2010) Y. Liu, L. F. Wei, W. Z. Jia, and J. Q. Liang, Phys. Rev. A 82, 045801 (2010).
• Liu et al. (2011) T. Liu, M. Feng, and K. Wang, Phys. Rev. A 84, 062109 (2011).
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• Jaynes and Cummings (1963) E. T. Jaynes and F. W. Cummings, Proc. IEEE 51, 89 (1963).
• Aharonov and Anandan (1987) Y. Aharonov and J. Anandan, Phys. Rev. Lett. 58, 1593 (1987).
• Zeng and Lei (1995) J. Y. Zeng and Y. A. Lei, Phys. Rev. A 51, 4415 (1995).
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• Berry (2009) M. V. Berry, J. Phys. A: Math. Theor. 42, 365303 (2009).
• Jones et al. (2000) J. A. Jones, V. Vedral, A. Ekert, and G. Castagnoli, Nature 403, 869 (2000).
• Du et al. (2003) J. Du, P. Zou, M. Shi, L. C. Kwek, J.-W. Pan, C. H. Oh, A. Ekert, D. K. L. Oi, and M. Ericsson, Phys. Rev. Lett. 91, 100403 (2003).
• Calvani et al. (2013a) D. Calvani, A. Cuccoli, N. I. Gidopoulos, and P. Verrucchi, Proc. Natl. Acad. Sci. USA 110, 6748 (2013a).
• Calvani et al. (2013b) D. Calvani, A. Cuccoli, N. I. Gidopoulos, and P. Verrucchi, Int. J. Theor. Phys. Online (2013b).
• Richter and Voigt (1994) J. Richter and A. Voigt, J. Phys. A: Math. Gen. 27, 1139 (1994).
• Deng and Fang (2008) H.-L. Deng and X.-M. Fang, J. Phys. B: At. Mol. Opt. Phys. 41, 025503 (2008).
• Samuel and Bhandari (1988) J. Samuel and R. Bhandari, Phys. Rev. Lett. 60, 2339 (1988).
• not (a) In the full text but this equation we set the reduced Planck constant .
• not (b) This shows the Berry phases induced by quantum field we obtained below violate the gauge invariance, as it can be affected by the choice of instantaneous eigenstates. However the difference of the Berry phases between two eigenstates is an invariant under the gauge transformations. This remark is also applicable to the results in Fuentes-Guridi et al. (2002) as well. One can change the Berry phases in Fuentes-Guridi et al. (2002) by replacing the phase shift operator by without influence on the rotation of the field.
• Layton et al. (1990) E. Layton, Y. Huang, and S.-I. Chu, Phys. Rev. A 41, 42 (1990).
• Wootters (1998) W. K. Wootters, Phys. Rev. Lett. 80, 2245 (1998).
• Chaturvedi et al. (1987) S. Chaturvedi, M. S. Sriram, and V. Srinivasan, J. Phys. A: Math. Gen. 20, L1071 (1987).
• Modi et al. (2010) K. Modi, T. Paterek, W. Son, V. Vedral, and M. Williamson, Phys. Rev. Lett. 104, 080501 (2010).
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# International Encyclopedia of Public Policy and Administration - Vol. 2
By Jay M. Shafritz | Go to book overview
Britain and the House of Representatives in the United States, and the second step involving the upper house, the House of Lords in Great Britain and the Senate in the United States. Impeachment is initiated by the lower house, which conducts an investigation and votes articles of impeachment detailing the alleged offenses. The second step is a trial in the upper chamber, which decides the truth or falsity of the charges contained in the articles of impeachment.
In both the United States and Great Britain, articles of impeachment must be approved by the lower house by a simple majority vote of those present. Since a quorum in the United States House of Representatives is 50 percent of the membership, impeachment may be approved by a vote of one-fourth of the total membership of the House plus one. Although not required by the Constitution, the United States House has always used one of its committees to investigate charges that a public official has committed an impeachable offense. This has usually involved fact- finding hearings by the committee.
Once articles of impeachment have been voted by the lower house, the upper house conducts a trial and then votes on each article of impeachment to determine whether the charge contained in that article is true. A finding that a charge is true is known as a "conviction." In the United States, a conviction must be approved by a twothirds majority of the senators present. In Great Britain, the house of Lords may convict by a simple majority. No conviction may be based on offenses not included in the articles of impeachment voted by the lower house.
In the United States, the vice president presides over all impeachment trials in the senate, except those involving the president. In cases involving impeachment of the president, the trial in the Senate is presided over by the chief justice of the Supreme Court. This latter provision was included because it would be unfair for the vice president to preside over a trial in which conviction of the charged party would result in the judge being elevated to the presidency.
The House selects managers from their own membership to serve as prosecutors in the Senate. The senators serve as jurors in deciding the truth or falsity of the charges. The charged official may be represented by counsel and has the right to appear in person. Each side may call witnesses and introduce documentary evidence. The presiding officer rules on questions of admissibility of evidence, but may be reversed by a majority vote of the senators present. There is no provision in the United States Constitution for disqualifying a senator from voting in an impeachment trial because of bias, prejudice, or interest.
Impeachment results in an immediate judgment of conviction and an order of removal from office by the presiding judge or officer of the trial. In addition, the Senate may vote to disqualify the convicted official from ever again holding public office in the United States. The United States Supreme Court has ruled that impeachment is not subject to judicial review.
PAUL M. BROWN
BIBLIOGRAPHY
Berger, Raoul, 1973. Impeachment: The Constitutional Problems. Cambridge, MA: Harvard University Press.
Black, Jr., Charles L. 1974. Impeachment: A Handbook. New Haven and London: Yale University Press.
Schaapper, M. B., ed., 1974. Presidential Impeachment: A Documentary Overview, Washington, DC: Public Affairs Press.
U.S. Congress. House of Representatives, Committee on the Judiciary, 1974. Constitutional Grounds for Impeachment: Report by the Staff of the Impeachment Inquiry, House of Representatives, Committee on the Judiciary. Ninety-third Congress, Second Session, February 1974: Washington, DC: GPO.
IMPERIALISM. The exertion of political dominance by one nation-state over the people of another nation-state or territory. As shall be seen, the precise source and nature of that domination varies considerably according to the nation-states and historical context concerned in specific cases. Indeed, the historical diversity of imperial systems makes it difficult to assert generalized principles that apply in all cases. Perhaps the only valid generalization is that imperialism is always based upon an uneven power relationship in which the imperializing nation is ultimately able to exert its will over the imperialized. This statement conjures up images of military coercion, but some systems of imperial control have endured without resort to such methods, and in some cases without the capacity for such aggressive measures. Economic sanctions can prove even more effective (and cheaper) than military assault.
Inevitably, generalized statements about imperialism have emerged from specific studies of particular imperial systems, and therefore the best way to address the subject is to examine some of the most important historical and sociological theories of imperialism. To this end, this entry is divided into three subsections. The first considers theories seeking to explain the motives and causes of imperial expansion. The second explores the varying natures of imperial systems, focusing upon the wide variety of ways in which imperial rule is maintained in different circumstances. The final section is concerned with the debate over the consequences of imperialism, whether harmful, indifferent, or beneficial.
Before proceeding, it is worth noting that imperialism appears to have been a constant in history. It was a feature of most stages of historical development in most ethnic and cultural communities. In Europe, imperialism was a characteristic of ancient Greece and Rome. China and the Muslim world also saw the development of empires. From the sixteenth century, the emergent modern European societies exerted control over Africa, Asia, and the Americas,
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## appleduardo Group Title whats the limit of the following function? could somebody help me pleasE? one year ago one year ago Edit Question Delete Cancel Submit
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1. appleduardo Group Title
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$\frac{ \sqrt{2-t}-\sqrt{2} }{ t }$
• one year ago
2. appleduardo Group Title
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t-->0
• one year ago
3. nasryn Group Title
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first you want to multiply the top and bottom by the reciprocal of the top
• one year ago
4. nasryn Group Title
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$\sqrt{2-t}+\sqrt{2}$
• one year ago
5. nasryn Group Title
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multiply top and bottom by that, and what do you get?
• one year ago
6. appleduardo Group Title
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yeep, but then i'll get this: $\frac{ 2-t-2 }{ t(\sqrt{2-t})+\sqrt{2}}$
• one year ago
7. nasryn Group Title
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right.
• one year ago
8. nasryn Group Title
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now simplify the top
• one year ago
9. appleduardo Group Title
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ill get:$\frac{ -t }{ t(\sqrt{2-t} +\sqrt{2}) }$
• one year ago
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also, the denominator should be $t(\sqrt{2-t}+\sqrt{2})$
• one year ago
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correct. now can you do anything with the top and bottom t's?
• one year ago
12. appleduardo Group Title
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is it right to cancel a negative t with a positive t ?
• one year ago
13. nasryn Group Title
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well, you just cancel the t's, the negative would stay.
• one year ago
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so you would get $\frac{ -1 }{ \sqrt{2-t}+\sqrt{2} }$
• one year ago
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now you can take the limit directly by plugging in 0.
• one year ago
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:O so the limit is: -0.353509207 ?
• one year ago
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well, I suppose if you want to do it that way, I would just say $\frac{ -1 }{ 2\sqrt{2} }$
• one year ago
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oh God youre a genius! thank you so much!!!
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:) no worries.
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https://physics.stackexchange.com/questions/176717/ground-state-for-interacting-field-thoeries
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# Ground state for interacting field thoeries
Are there references where the ground state of an interacting quantum field theory is explicitly written in terms of states of the underlying free theory?
For example, let us suppose to have a self interacting scalar field theory (with a potential $\phi^4$). Are there references expressing its ground state in terms of free states of the underlying free scalar field theory (without the potential $\phi^4$)?
In fact, there are an many references about perturbation theory in field theory but I do not seem to find one addressing this problem. For example, I guess it might be possible to use some standard time-independent perturbation theory but it would be nice to have a reference as guidance to correctly deal with the infinities.
Here I constructed perturbation-like approximants converging to the vacuum in $\phi^4_2g(x)$ (technically an interacting QFT, although not translation invariant, so Haag's theorem does not apply). There are no "infinities" in this case.
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https://software.acellera.com/docs/latest/htmd/htmd.protocols.equilibration_v2.html
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# htmd.protocols.equilibration_v2 module¶
class htmd.protocols.equilibration_v2.Equilibration(_version=3)
Bases: protocolinterface.protocolinterface.ProtocolInterface
Equilibration protocol v2
Equilibration protocol for globular and membrane proteins It includes a flatbottom potential box to retrain a ligand for example within this box.
Parameters
• runtime (float, default=0) – Running time of the simulation.
• timeunits (str, default='steps') – Units for time arguments. Can be ‘steps’, ‘ns’ etc.
• temperature (float, default=300) – Temperature of the thermostat in Kelvin
• fb_k (float, default=0) – Force constant of the flatbottom potential in kcal/mol/A^2. E.g. 5
• fb_reference (str, default='none') – Reference selection to use as dynamic center of the flatbottom box.
• fb_selection (str, default='none') – Selection of atoms to apply the flatbottom potential
• fb_box (list, default=[0, 0, 0, 0, 0, 0]) – Position of the flatbottom box in term of the reference center given as [xmin, xmax, ymin, ymax, zmin, zmax]
• useconstantratio (bool, default=False) – For membrane protein simulations set it to true so that the barostat does not modify the xy aspect ratio.
• constraints (dict, default={'protein and name CA': 1, 'protein and noh and not name CA': 0.1}) – A dictionary of atomselections and values of the constraint to be applied (in kcal/mol/A^2). Atomselects must be mutually exclusive.
• nvtsteps (int, default=500) – Number of initial steps to apply NVT in units of 4fs.
• constraintsteps (int, default=None) – Number of initial steps to apply constraints in units of 4fs. Defaults to half the simulation time.
Example
>>> from htmd.protocols.equilibration_v2 import Equilibration
>>> md = Equilibration()
>>> md.runtime = 4
>>> md.timeunits = 'ns'
>>> md.temperature = 300
>>> md.useconstantratio = True # only for membrane sims
>>> # this is only needed for setting the flatbottom potential, otherwise remove it
>>> md.fb_reference = 'protein and resid 293'
>>> md.fb_selection = 'segname L and noh'
>>> md.fb_box = [-25, 25, -25, 25, 43, 45]
>>> md.fb_k = 5
>>> md.write('./build','./equil')
addConstraint(atomselect, factor=1)
Convenience function for adding a new constraint to existing constraints.
Parameters
• atomselect (str) – Atom selection of atoms we want to constrain
• factor (float) – The scaling factor of the constraints applied to the atoms
Example
>>> eq.addConstraint('chain X', 0.3)
write(inputdir, outputdir)
Write the equilibration protocol
Writes the equilibration protocol and files into a folder for execution using files inside the inputdir directory
Parameters
• inputdir (str) – Path to a directory containing the files produced by a build process.
• outputdir (str) – Directory where to write the equilibration setup files.
Examples
>>> md = Equilibration()
>>> md.write('./build','./equil')
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https://overbrace.com/bernardparent/viewtopic.php?f=17&t=307&start=10
|
Intermediate Thermodynamics Assignment 4 — Conservation of Energy
There was a typo in the formulation of Question 2, and this is why the answers for Q2 seemed wrong. Check the problem formulation again.
04.23.19
Previous 1 , 2 • PDF 1✕1 2✕1 2✕2
$\pi$
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https://smashville247.net/ionic-compounds-are-composed-of-metals-and-nonmetals/
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describe the development of covalent bonds explain the energetics the covalent link formation and also breakage
Video $$\PageIndex1$$: What space covalent bonds?
Nonmetal atoms frequently kind covalent binding with other nonmetal atoms. Because that example, the hydrogen molecule, H2, consists of a covalent bond between its 2 hydrogen atoms. Number $$\PageIndex1$$ illustrates why this bond is formed. Beginning on the far right, we have two separate hydrogen atoms with a particular potential energy, indicated by the red line. Along the x-axis is the distance between the two atoms. Together the two atoms technique each other (moving left along the x-axis), your valence orbitals (1s) start to overlap. The single electrons on every hydrogen atom then communicate with both atom nuclei, occupying the space around both atoms. The solid attraction the each mutual electron come both nuclei stabilizes the system, and the potential energy decreases as the bond street decreases. If the atoms proceed to method each other, the hopeful charges in the two nuclei begin to repel every other, and also the potential power increases. The bond length is figured out by the street at which the lowest potential energy is achieved.
You are watching: Ionic compounds are composed of metals and nonmetals
Figure $$\PageIndex1$$: The potential energy of two different hydrogen atom (right) decreases together they strategy each other, and the single electrons on every atom are common to form a covalent bond. The bond size is the internuclear distance at i m sorry the shortest potential energy is achieved.
It is vital to psychic that power must be included to rest smashville247.netical bonds (an endothermic process), whereas developing smashville247.netical binding releases power (an exothermic process). In the case of H2, the covalent link is really strong; a big amount that energy, 436 kJ, have to be added to rest the bond in one mole the hydrogen molecules and also cause the atoms to separate:
\<\ceH2(g)⟶\ce2H(g)\hspace20pxΔH=\mathrm436\:kJ\>
Conversely, the very same amount of power is released as soon as one mole that H2 molecules creates from 2 moles that H atoms:
\<\ce2H(g)⟶\ceH2(g)\hspace20pxΔH=\mathrm−436\:kJ\>
## Pure vs. Polar Covalent Bonds
If the atom that type a covalent bond are identical, as in H2, Cl2, and also other diatomic molecules, climate the electrons in the bond need to be mutual equally. We refer to this as a pure covalent bond. Electrons mutual in pure covalent bonds have an equal probability that being near each nucleus. In the instance of Cl2, every atom starts off with 7 valence electrons, and also each Cl shares one electron through the other, developing one covalent bond:
\<\ceCl + Cl⟶Cl2\>
The total number of electrons about each separation, personal, instance atom consists of six nonbonding electrons and two mutual (i.e., bonding) electrons for eight total electrons, equivalent the number of valence electrons in the noble gas argon. Since the bonding atoms space identical, Cl2 additionally features a pure covalent bond.
When the atoms attached by a covalent bond are different, the bonding electrons are shared, however no much longer equally. Instead, the bonding electron are much more attracted to one atom 보다 the other, giving rise to a change of electron density toward that atom. This unequal distribution of electrons is well-known as a polar covalent bond, defined by a partial confident charge on one atom and also a partial an adverse charge ~ above the other. The atom the attracts the electrons more strongly acquires the partial negative charge and vice versa. Because that example, the electron in the H–Cl shortcut of a hydrogen chloride molecule spend more time near the chlorine atom than close to the hydrogen atom. Thus, in one HCl molecule, the chlorine atom tote a partial an unfavorable charge and also the hydrogen atom has a partial hopeful charge. Number $$\PageIndex2$$ shows the circulation of electron in the H–Cl bond. Keep in mind that the shaded area around Cl is much larger than it is approximately H. Compare this to number $$\PageIndex1$$, which mirrors the even distribution of electron in the H2 nonpolar bond.
See more: Liquor Laws And The Legal Drinking Age In Las Vegas Nevada Liquor Laws
\<\ceH_2(g) + Cl_2(g)⟶2HCl_(g) \labelEQ4\>
or
\<\ceH–H_(g) + Cl–Cl_(g)⟶2H–Cl_(g) \label\EQ5\>
To kind two mole of HCl, one mole of H–H bonds and also one mole the Cl–Cl bonds need to be broken. The energy required come break these bonds is the amount of the bond energy of the H–H link (436 kJ/mol) and the Cl–Cl link (243 kJ/mol). During the reaction, 2 moles the H–Cl bonds are formed (bond energy = 432 kJ/mol), release 2 × 432 kJ; or 864 kJ. Since the bonds in the commodities are more powerful than those in the reactants, the reaction releases much more energy 보다 it consumes:
\<\begin align*ΔH&= \sum \mathrmD_bonds\: broken− \sum \mathrmD_bonds\: formed\\ΔH&=\mathrm−2D_H−Cl\\&=\mathrm<436+243>−2(432)=−185\:kJ\end align*\>
This excess power is released as heat, therefore the reaction is exothermic. Table T2 provides a value for the traditional molar enthalpy of formation of HCl(g), $$ΔH^\circ_\ce f$$, that –92.307 kJ/mol. Twice that value is –184.6 kJ, i beg your pardon agrees well with the answer derived earlier because that the formation of 2 moles the HCl.
Example $$\PageIndex1$$: using Bond Energies to approximate Enthalpy Changes
Methanol, CH3OH, might be fantastic alternative fuel. The high-temperature reaction of steam and carbon to produce a mixture that the gases carbon monoxide, CO, and also hydrogen, H2, from which methanol can be produced. Making use of the shortcut energies in Table $$\PageIndex2$$, calculate the approximate enthalpy change, ΔH, for the reaction here:
\
Solution
First, we have to write the Lewis frameworks of the reactants and also the products:
From this, we see that ΔH for this reaction involves the power required to break a C–O triple bond and two H–H solitary bonds, as well as the energy produced by the formation of 3 C–H solitary bonds, a C–O solitary bond, and an O–H single bond. We have the right to express this as complies with (via Equation \refEQ3):
\<\begin align*ΔH&= \sum D_bonds\: broken− \sum D_bonds\: formed\\ΔH&=\mathrm−<3(D_C−H)+D_C−O+D_O−H>\end align*\>
Using the bond energy values in Table $$\PageIndex2$$, us obtain:
We have the right to compare this value to the worth calculated based upon $$ΔH^\circ_\ce f$$ data native Appendix G:
Exercise $$\PageIndex1$$
Ethyl alcohol, CH3CH2OH, was one of the an initial organic smashville247.neticals intentionally synthesized by humans. It has many uses in industry, and also it is the alcohol included in alcohol addict beverages. It have the right to be obtained by the fermentation of street or synthesized by the hydration that ethylene in the following reaction:
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https://www.lessonplanet.com/teachers/fractions-with-common-denomitors
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# Fractions with common denomitors
##### This Fractions with common denomitors worksheet also includes:
In this fractions worksheet, students add the fractions together with common denominators and reduce them to their smallest terms. Students add 18 problems.
Concepts
Resource Details
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https://www.physicsoverflow.org/363/how-to-prove-quantum-n-4-super-yang-mills-is-superconformal
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# How to prove quantum N=4 Super-Yang-Mills is superconformal?
+ 5 like - 0 dislike
62 views
I'm especially interested in elegant illuminating proofs which don't involve a lot of straightforward technical computations
Also, does a non-perturbative proof exist?
This post has been migrated from (A51.SE)
retagged Apr 19, 2014
+ 8 like - 0 dislike
In any supersymmetric theory you can choose the gauge coupling to be the coefficient of W_\alpha^2 in the superpotential. This gauge coupling runs only at one-loop, which is a fundamental consequence of the non-renormalization theorems. The other possible running coefficients are the kinetic terms, Z(\mu)QQ^\dagger. These generally get renormalized to all orders in perturbation theory.
In N=4 the one-loop coefficient is zero. This is trivial (just counting the fields). Hence, the gauge coupling (as defined above) does not run. But N=4 relates the gauge particles with the chiral superfields (all the matter particles sit in one big representation of N=4) and so the latter cannot get renormalized either.
This is a slick and intuitive argument... Similar logic operates in many N=2 theories as well.
This post has been migrated from (A51.SE)
answered Nov 2, 2011 by (650 points)
Nice answer. Can you provide a ref pls? Do I understand correctly this argument is perturbative only? If so, is there a way to extend it to a nonperturbative one?
This post has been migrated from (A51.SE)
It is non-perturbative, because the gauge coupling does not run non-perturbatively. I have not seen it explicitly written anywhere, but I am sure I am (by far) not the first one who had this thought :)
This post has been migrated from (A51.SE)
Your argument is definitely nicer :)
This post has been migrated from (A51.SE)
Yuji: I think you may need to resort to this argument anyway, even if you do Leigh-Strassler. This is because the latter only implies a one-dimensional line of CFTs, but it does not prove that this one-dimensional line coincides with the line on which N=4 sits. So at some point you have to invoke the higher symmetry.
This post has been migrated from (A51.SE)
Ok, so can you provide a ref to the nonrenormalization theorem you are using?
This post has been migrated from (A51.SE)
Page 96 in http://www.physics.uc.edu/~argyres/661/susy1996.pdf reviews the argument. In general you can prove that it is one-loop+non-perturbative contributions. In N=4 since there is no one-loop there is no \Lambda and so also the non-perturbative contributions are absent.
This post has been migrated from (A51.SE)
@Zohar I was just wondering if in reference to the original question one might refer to Seiberg's paper http://www.sciencedirect.com/science/article/pii/0370269388912658 Isn't this paper the first non-perturbative argument for the superconformality of N=4 SYM ? And also is the argument for superconformality in N=4 SYM conceptually different from the one needed in this one of my earlier questions - http://physics.stackexchange.com/questions/11438/argument-for-quantum-theoretic-conformality-of-caln-2-super-chern-simons-t
This post has been migrated from (A51.SE)
+ 7 like - 0 dislike
Regard it as an N=1 super Yang-Mills theory with three adjoint chiral superfields, and apply the non-perturbative analysis of Leigh-Strassler.
This post has been migrated from (A51.SE)
answered Oct 27, 2011 by (1,390 points)
It would be nice if you can add a short summary of this method
This post has been migrated from (A51.SE)
Please use answers only to (at least partly) answer questions. To comment, discuss, or ask for clarification, leave a comment instead. To mask links under text, please type your text, highlight it, and click the "link" button. You can then enter your link URL. Please consult the FAQ for as to how to format your post. This is the answer box; if you want to write a comment instead, please use the 'add comment' button. Live preview (may slow down editor) Preview Your name to display (optional): Email me at this address if my answer is selected or commented on: Privacy: Your email address will only be used for sending these notifications. Anti-spam verification: If you are a human please identify the position of the character covered by the symbol $\varnothing$ in the following word:p$\varnothing$ysicsOverflowThen drag the red bullet below over the corresponding character of our banner. When you drop it there, the bullet changes to green (on slow internet connections after a few seconds). To avoid this verification in future, please log in or register.
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http://mathoverflow.net/questions/64029/if-a-manifold-suspends-to-a-sphere?sort=newest
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If a manifold suspends to a sphere…
I have a topological manifold whose suspension is homeomorphic to the sphere $S^{k+1}$. Is it necessarily itself homeomorphic to $S^k$?
I know that this is not true if I replace "suspension" with "double suspension", because I found the helpfully named http://en.wikipedia.org/wiki/Double_suspension_theorem.
-
This is way outside my area of expertise, so perhaps someone can explain why the answer does not follow from the double suspension theorem: start with the Poincare dodecahedral space $M$ (a homology 3-sphere with nontrivial fundamenatal group) and suspend it once. If you get something homeomorphic to $S^4$, then $M$ is a counterexample. If not, then by DST $SM$ is homeomorphic to $S^5$ so $SM$ is a counterexample. – Pete L. Clark May 5 '11 at 18:29
Interesting plan! But it is not obvious to me that the suspension of M (or any other space obtained by a similar method) is a topological manifold. – James Cranch May 5 '11 at 18:54
Okay, so that's what I was missing: that the suspension of a manifold might or might not be a manifold. Like I said: not my area of expertise. (I guess the upvotes on my previous comment mean: "yes, I was wondering that too...") – Pete L. Clark May 5 '11 at 20:15
Yes, it's pretty easy that the suspension of a space $X$ cannot possibly be an $n+1$-manifold unless $X$ is homotopy equivalent to $S^n$. – Tom Goodwillie May 6 '11 at 0:37
Suppose $M$ is a closed $n$-manifold whose suspension is homeomorphic to $S^{n+1}$. Removing the two "singular" points from the suspension gives $M\times \mathbb R$, while removing two points from $S^{n+1}$ gives $S^n\times\mathbb R$. Thus $M\times \mathbb R$ and $S^n\times\mathbb R$ are homeomorphic, which easily implies that $M$ and $S^n$ are h-cobordant, and hence $M$ and $S^n$ are homeomorphic.
You need $n>4$, though, don't you? – Benoît Kloeckner May 5 '11 at 19:10
To see that $M$ and $S^n$ are h-cobordant consider a homeomorphism $h$ of their products with $\mathbb R$, and use excision in homology to show that the submanifolds $S^n\times 0$ and $h(M\times t)$ bound an h-cobordism, where $t$ need to be sufficiently large to ensure that the submanifolds are disjoint. – Igor Belegradek May 5 '11 at 19:38
In fact, one need not involve h-cobordisms at all: just note that $M$ and $S^n$ are homotopy equivalent and use Poincare's conjecture. I guess, I just like to advertize that fact that if two closed manifolds become homeomorphic after multiplying by $\mathbb R$, then they are $h$-cobordant. :) – Igor Belegradek May 5 '11 at 20:11
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http://dojiboy9.atspace.cc/contest/view-post.php?p=camelot
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# Camelot
We are given an $$r \times c$$ chessboard $$(1 \leq R \leq 30, \ 1 \leq C \leq 26)$$ where some cells have knights and one cell has a king.The knights and king can move freely, and there can be more than one piece in any cell at any time (the cells are very "large"). The goal is to select a cell for all of the pieces to meet in, in such a way that the sum of the number of moves taken by all pieces is minimal. At any point, if a king and a knight occupy the same cell, the king may join with the knight, and the two pieces become one knight piece.
1. Euler tour?
2. Shortest paths
3. Floyd-Warshall algorithm
4. Pick a knight to pick-up the king
5. Greedy (always meet on a king, or a knight?)
###### Algorithm 1.1
Use floyd-warshall to compute all shortest paths by knight and by king.
For each (meeting-point s, pick-up-point p, knight to pick up the king k):
cost(s,p,k) = dist(k,p,by_knight) + dist(king,p,by_king) + dist(p,s,by_knight)
For each knight h != k:
cost(s,p,k) += dist(h,s)
return min(cost(s,p,k)) over all (s,p,k)
Basically the main idea is to use Floyd-Warshall to compute all the distances. We then pick a knight to go pick up the king, and also a cell where they should meet. Given a meeting cell, a pick-up cell, and a knight, we can use the previously computed distances to calculate the total sum of distances / moves. Take the minimum over all such choices, and this must be our answer. This approach is correct. However, it is far too slow. The Floyd-Warshall algorithm alone runs in $$O(N^3)$$ time where $$N = R \times C$$ is the number of cells, which can be around 800. So, this approach got TLE.
Since the number of nodes is too high, an $$O(N^3)$$ algorithm is too slow. Therefore, I need an algorithm that is based on some greedy observation or on classic "shortest path" algorithms, if I hope to solve this problem.
The conditions are complicated and not independent. How does the problem vary when we drop some combination of the conditions?
How do we solve this problem if we were not given any king at all?
If we have no king, we simply have to find the s which minimizes the sum of distances to all knights. Doing Floyd-Warshall is still too slow here, so we can't use it at all. However, we can use Dijkstra's algorithm, once from each possible "meeting-point", to compute the distances, and then take the sum. There is probably no better way to solve this modified problem anyway. With Dijkstra's algorithm, we can solve this in $$O(NlogN)$$ time per "meeting-point". So we get $$O(N^2logN)$$ in total, which is better than $$O(N^3)$$.
What if we only have a king (no knights)?
If we just have a king, we should always just place the meeting point on the king (obviously). If we (for some reason) still had to go through all meeting points, the answer is just $$\max(dx,dy)$$ where $$dx$$ and $$dy$$ are the absolute differences of $$x$$ and $$y$$ coordinate from the king to the meeting point; we would then try all meeting points (this solution would likely be $$O(N)$$).
What if we have a king, but we need not "pick-up" the king?
Then these problems are independent. We simply proceed with dijkstra's, computing the distances, and also computing the king distance. We then sum over these and take the minimum meeting point.
In attempting to generalize to the "pick-up-the-king" version, the above simplifications reminded me of something which I've heard called "2D-Dijkstra". In essence, we use a modified version of Dijkstra's algorithm, maintaining more than one value (i.e.: a pair, triple, tuple, or list of values) at each node; the values will be modified similarly to with Dijkstra's algorithm, but may not directly correspond to a "shortest" path (or may correspond to a shortest path on some auxiliary graph).
Given a fixed meeting-point $$s$$, can we do some kind of modified Dijkstra's algorithm (or possibly a 2D-Dijkstra) to solve the main problem? (It seems like this is the right approach based on the simplified problems; we have to try each source anyway, it seems.)
Assume that we have a fixed meeting cell $$s$$, and a king starting at some fixed cell $$k$$. Take any cell $$(r,c)$$; Take any path from $$(r,c)$$ to $$s$$. We define the detour distance of this path to be the total number of steps that a knight would take on this path, plus the minimum number of steps that it would take for the king $$k$$ to move to some cell on this path.
That is, the detour distance of this path is the total number of moves needed if a knight at $$(r,c)$$ were to go pick up the king somewhere on this path, and the king were to move to that cell, and then they would travel together (as one knight) to $$s$$.
With a fixed meeting cell $$s$$ and a king $$k$$, we define the detour distance of the cell $$(r,c)$$ to be the minimum detour distance over all paths from $$(r,c)$$ to $$s$$. The detour distance of cell $$(r,c)$$ will be denoted $$f(r,c)$$.
The goal is that, hopefully, these "detour distances", defined as above, can be computed via Dijkstra's algorithm in some way.
Two cells $$(r,c)$$ and $$(r',c')$$ are said to be neighbors if a knight on cell $$(r,c)$$ can move to cell $$(r',c')$$ in one step.
How do detour distances of neighbors relate? In particular, can we generate formulas and inequalities that relate detour distances of neighbors similarly to regular distances?
After fiddling around with some formulas, we get the following lemma.
$f(r,c) \leq \min_{\text{neighbors} (r',c')}{f(r', c') + 1}$
Take any optimal solution (i.e.: a path which generates a shortest detour distance) for $$(r,c)$$. There are two cases: either the king comes to this cell, or it does not. If the king must come to that cell, then the "detour distance" of any knight starting on that cell is the sum of the number of moves it takes for the king to get to that cell and for a knight to go from that cell to the meeting-point $$s$$. If the king will not go to that cell, then any knight starting on $$(r,c)$$ which is to pick up the king must travel at least one unit away. Hence, it must travel through some neighboring cell $$(r',c')$$ (which takes 1 step). After that, we can take the shortest path to pick up the king and go to the end from there (which takes $$f(r',c')$$ steps by definition). And this can be extended to any pair of neighbors. $$(r,c)$$ can always take a path through $$(r',c')$$. So, $$f(r,c) \leq (r',c') + 1$$. Furthermore, there must be some neighbor for which this applies (or else the first case applies, and the king must travel to the cell $$(r,c)$$). This proves the statement.
We can apply a modified version of Dijkstra's algorithm to solve this problem.
See analyses of the Algorithm below. Also, see my tutorial on shortest paths. Generally speaking, we have a graph where the nodes are the cells, and there are edges of length 1 between neighbors, and the weight of the "empty" path is some number dependent on the vertex it is on.
Let $$d(r,c)$$ be the distance (by knight) from cell $$(r,c)$$ to point $$s$$. Let $$f(r,c)$$ be the detour distance from cell $$(r,c)$$ to point $$s$$. MEETING-POINT(R, C, king_r, king_c, knights):
ans = infinity
For each possible meeting-point s:
Compute d(r,c) over all cells (r,c) by Dijkstra from s.
For each cell (r,c):
f(r,c) = d(r,c) + (distance from king to (r,c) by king-steps)
while(f(r,c) > f(r',c') + 1) for some neighbors (r,c) and (r',c'):
Choose the (r',c') with the minimum f(r',c') value
Set f(r,c) = f(r',c') + 1
The above algorithm is equivalent to running Dijkstra's algorithm on an auxiliary graph which would return the correct detour distances.
For each cell $$(r,c)$$ we define two auxiliary nodes: $$(r,c,no)$$ and $$(r,c,yes)$$ to represent a knight being on cell $$(r,c)$$ without the king, or with the king (respectively). We construct a graph on these auxiliary nodes so that an edge exists between $$(r,c,no)$$ and $$(r',c',no)$$ of length 1 if $$(r,c)$$ and $$(r',c')$$ are neighbors by knight. Similarly, an edge exists between $$(r,c,yes)$$ and $$(r',c',yes)$$ of length 1 for neighbors $$(r,c)$$ and $$(r',c')$$ by knight. Now, an edge exists between $$(r,c,no)$$ and $$(r,c,yes)$$ of length equal to the minimum steps it would take to get from the king to the cell $$(r,c)$$ by king-steps. Informally, we can model this problem by knights either "taking a step" or "calling the king". The king does not move until some knight specifically calls it to the knight's cell. Then, the king will travel directly to that cell, and the knight will now "have" the king; and the knight can then move on, taking steps again. Once the king has been "called" to the knight at cell $$(r,c)$$, the knight moves from state $$(r,c,no)$$ to state $$(r,c,yes)$$. So, the total number of "steps" needed to transition from $$(r,c,no)$$ to $$(r,c,yes)$$ was exactly the number of steps it took the king to get to cell $$(r,c)$$. Then, the detour distance $$f(r,c)$$ to a fixed cell $$s = (sr,sc)$$ can actually be seen as the shortest path distance from $$(r,c,no)$$ to $$(sr,sc,yes)$$. That is, we must eventually end up at cell $$s$$, and we must eventually have the king. This corresponds to eventually ending up in cell $$(sr,sc,yes)$$. And the minimum weight path over all these is the solution. (Note: This also gives us an alternative algorithm for solving this problem.) To show the reduction from our algorithm above to the shortest path algorithm described in this proof, we notice that, for any cell $$(r,c)$$, the distance from $$(r,c,yes)$$ to $$(sr,sc,yes)$$ is just the length of the shortest direct path (i.e.: minimum number of steps a knight must take to get there, $$d(r,c)$$). Once a knight has the king, the knight can simply move directly to the sink cell $$s$$. So, for a node $$(r,c,no)$$, the length of the path is no more than the length of the path $$(r,c,yes)$$ plus the cost of achieving/calling the king. This is equal to $$d(r,c) + \text{(distance from king to (r,c) by king-steps)}$$. And this is exactly what we initialize $$f(r,c)$$ to for each node $$(r,c)$$. Then, after some iterations, we update $$f(r,c)$$ based on the edges, which is equivalent to updating the distances of nodes $$(r,c,no)$$ based on neighbors $$(r',c',no)$$. Hence, our above algorithm is equivalent to running Dijkstra's algorithm on this auxiliary graph; but our algorithm automatically fills in the distances for the $$(r,c,yes)$$ nodes to be $$d(r,c)$$ (which they would be by the end of Dijkstra's algorithm anyway) and skips directly to the point in the algorithm where the $$(r,c,no)$$ nodes need to filled in. So, in the end $$f(r,c)$$ will be set exactly equal to the proper detour distance according to a reduction to this auxiliary graph.
Upon termination of the algorithm above, $$f(r,c)$$ will be equal to the detour distance of cell $$(r,c)$$.
We could also solve this problem by doing Dijkstra's algorithm directly on the auxiliary graph. This would be an alternative approach
The above algorithm can be made to run in $$O(N \log N)$$ time using the priority queue version of Dijkstra's algorithm.
In the end, this problem was reducible to solving shortest paths on multiple sources. Whenever one has multiple-source shortest-paths, the immediate idea is to use Floyd-Warshall's algorithm for this, due to its simplicity to code. However, the Floyd-Warshall algorithm runs in $$O(N^3)$$ (where N is the number of edges) whereas (at least for sparse graphs with small edges, in this case), simply calling Dijkstra's algorithm once for each source is $$O(N^2 \log N)$$ or something similar, which is much faster. In fact, in this problem, with $$N=800$$, Floyd-Warshall was utterly impossible. Once having decided that we want to use some variant of Dijkstra's algorithm once for each "source" (where I am using a "source" to mean "final meeting place"; it might be better to call it a "sink", but hopefully the reader understands), it is not easy to figure out "how" to use Dijkstra's algorithm here. The key realization is that, for a knight on cell $$(r,c)$$ either the king will go there directly, or the cell will have to make at least one step before meeting the king. This "at least one step" property is the key property that allows this problem to be solvable by Dijkstra's algorithm. Specifically, that means that the "detour distance" of a cell $$(r,c)$$ is no more than the detour distance of any of its knightly-neighbors, plus 1. This yields an inequality that smells a lot like the shortest-path inequalities: $$f(r,c) \leq f(r',c') + 1$$ over all neighbors $$(r',c')$$ (where neighbors are those which can be reached in one knight-step). After working this out, one comes to either a reduction to an auxiliary graph (where the states are the cells, along with an additional bit for whether the knight has the king or not), or a modified Dijkstra's algorithm that computes these $$f(r,c)$$ directly. This problem was neat because it was a nice demonstration of modified shortest paths, especially non-trivial reductions. It also showed that, anytime we can get a system of inequalities of the form: $$f(x) \leq f(x') + w(x,x')$$, then we can likely solve the problem via shortest paths in some form or another.
1. $$f(r,c) \leq \min_{\text{neighbors} (r',c')}{f(r', c') + 1}$$ (the detour distance of a cell is no more than 1 plus the detour distance of its neighbor). This was the crucial observation. It took me all of my mental capabilities to get to this observation (probably because I was too busy thinking about optimizing the Floyd-Warshall brute-force approach). But the way I realized this was by applying some problem solving processes (namely, "drop and/or vary the conditions", or "simplify the problem") and realizing that, even under a simplified version of this problem, Dijkstra's algorithm would be required in some capacity.
2. This problem is reducible to Dijkstra's algorithm on an auxiliary graph. This became immediately intuitive once we realized the inequalities. It was much harder to prove this though. In the end I simply wrote the code for a "modified dijkstra's algorithm" that appeared correct; and it took me several attempts at this analysis before I could formally prove its correctness. In the end, my formal proof of correctness relied on reducing it to another algorithm (which was more literally an application of Dijkstra's algorithm); I would have liked to use a more direct proof. But nonetheless, sometimes it is better to code first and prove later, for problems that are "intuitive but hard to prove".
1. Recognizing more quickly that an $$O(N^3)$$ algorithm is too slow would have saved me a lot of time on this problem. Being able to recognize the necessity for a greedy or classic shortest-path algorithm would have been an asset.
2. The conditions / constraints (meet up at a place, pick up king, shortest path, etc.) were far to interrelated and dependent. A good problem-solving technique is to vary the constraints, drop different combinations of the constraints, and solve simpler forms of the problem, in order to determine what underlying structures there are inherent to the problem. For me, this meant asking the questions:
1. What happens if there is no king?
2. What happens if there is only a king and no knights? (With variations on this)
3. What about if there are kings and knights, but they can't "combine"?
These lead to some insights about the structure of this problem. For example, without a king, we still have to perform some kind of dijkstra's algorithm from each source, since Floyd-Warshall is too slow anyway.
3. I remembered the buzz-words: "2D-Dijkstra" and "modified Dijkstra". Once I decided that I wanted to use shortest-paths, I focused my attention on these kinds of algorithms (variants of Dijkstra's algorithm), which eventually became the final solution.
• Shortest Paths / Dijkstra's Algorithm / Modified Dijkstra
• Shortest Paths / All-Pairs Shortest Paths / Sparse Graphs
• Checkerboard / Chess Board / Knights and Kings
• Intuition / Intuitive but Hard to Prove problems
• Graph Theory / Shortest Paths
• Steiner Trees / Minimum Spanning Trees?
• I need to ask good questions (i.e.: the "problem-solving questions"). By asking "How does this problem change when I vary / drop some conditions", I was able to better understand the structure of the problem and then solve it.
• Anytime I have a set of objects, and a function over that set of objects that preserves some inequalities of the form: $$f(x) \leq f(y) + w(y,x)$$, then we can apply shortest path algorithms. We can apply shortest path algorithms in more general (but very similary) settings, depending on our definitions of $$+", \leq",$$ and $$w(y,x)$$. As such, I decided to write a tutorial / post analyzing the general shortest-path problem. See the tutorial here.
• Try FIXING one of the parameters (in this case, the source/sink cell).
|
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https://repository.uantwerpen.be/link/irua/111815
|
Publication
Title
Modeling ultrashort laser-induced emission from a negatively biased metal
Author
Abstract
A theoretical study of ultrashort laser-induced electron emission from a negatively biased metallic cathode has been performed. Classical as well as tunneling electron emission mechanisms are considered. It was found that electron emission is governed by an interplay of processes inside as well as above the cathode. A hybrid model is proposed, where the electron distribution within the target is retrieved from Boltzmann scattering integrals, while the charge distribution above it is studied by a Particle-In-Cell simulation. The results indicate that non-equilibrium effects determine the initial emission process, whereas the space charge above the target suppresses the effectively emitted charge.
Language
English
Source (journal)
Applied physics letters / American Institute of Physics. - New York, N.Y., 1962, currens
Publication
New York, N.Y. : American Institute of Physics, 2013
ISSN
0003-6951 [print]
1077-3118 [online]
Volume/pages
103:22(2013), p. 1-4
Article Reference
221603
ISI
000327696300020
Medium
E-only publicatie
Full text (Publisher's DOI)
Full text (publisher's version - intranet only)
UAntwerpen
Faculty/Department Research group [E?say:metaLocaldata.cgzprojectinf] Publication type Subject Affiliation Publications with a UAntwerp address
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http://cloud.originlab.com/doc/en/OriginC/ref/ocmath_smooth
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# 2.1.22.4.5 ocmath_smooth
## Description
smoothing. have 3 methods: median filter, Savitzky-Golay smoothing and adjacent averaging smoothing.
## Syntax
int ocmath_smooth( int nSize, const double * pY, double * pSmooth, int nLeftpts, int nMethod = SMOOTH_SG, int nBoundary = EDGEPAD_NONE, int nRightpts = -1, int nPolydeg = 2, int nDervOrder = 0, double dPercent = 50, bool bWeight = false, bool bAveraging = false )
## Parameters
nSize
[input] vector size of both pY and pSmooth
pY
[input] pointer to Y vector data.
pSmooth
[output] pointer to smoothed data, or derivatives, depending on nDervOrder(only for Savitzky-Golay smoothing).
nLeftpts
[input] if do Savitzky-Golay smoothing,number of data points to the left to be used in filter convolution,
if do median filter, Number of surrounding points to left and right. Thus the number of points considered in each segment is (2*nPts + 1).
if do adjacent averaging smoothing, is the window's size.
nMethod
[input] smoothing method.
SMOOTH_ADJAVE adjacent averaging smoothing
SMOOTH_SG Savitzky-Golay smoothing
SMOOTH_MEDIAN_FILTER median filter
nBoundary
[input] data are padded on both ends. Possible values are
EDGEPAD_NONE no padding
EDGEPAD_REFLECT pad reflect, end points are repeated such that on the left, [-1] = [0], [-2] = [1], [-3] = [2] and etc
EDGEPAD_REPEAT pad with [0] values the left and with [nSize-1] on the right
EDGEPAD_EXTRAPOLATE linear extrapolation using nLeft points on the left and nRight points on the right
EDGEPAD_PERIODIC pad periodic, [-1] = [nSize -1], [-2] = [nSize - 2]
nRightpts
[input] for Savitzky-Golay smoothing. number of data points to the right to be used in filter convolution, default (-1) will assume nLeft.
Total number of points used in the polynomial fits are (nLeft + nRight + 1) and it must be odd, namely nLeft + nRight must be even.
nPolydeg
[input] for Savitzky-Golay smoothing.The polynomial order. Higher order will preserve sharper features. nPolyDeg must be less then (nLeft + nRight + 1).
nDervOrder
[input] for Savitzky-Golay smoothing. order of derivative desired (0 = smoothing). To generate a fourth derivative, a minimum quartic (order 4) smoothing must be used.
For a third derivative, a minimum cubic (order 3) smoothing is needed. Similarly, a second derivative requires a minimum quadratic (order 2) smoothing.
dPercent
[input] for median filter.The percent for computing median.
bWeight
[input] for adjacent averaging smoothing. weight smooth or not. default is not(FALSE)
bAveraging
[input] for median filter.If true, the function will average the most nearest neighbors if there is no match to the given percent.
## Return
OE_NOERROR for success
## Examples
EX1
//Assume in the current graph, curve's XY data is in the first data plot. This piece
//of code get the XY data of the curve from the first data plot and smooth on it.
//The result is output in a new worksheet and the smoothing curve will plot in the
//original data plot with color red.
void ocmath_smooth_ex1()
{
GraphLayer gl = Project.ActiveLayer();
if (!gl)
{
out_str("Active layer is not a graph.");
return;
}
//get XY data from the first dataplot
DataPlot dp = gl.DataPlots(0);
DataRange dr;
vector vx, vy;
if(dp.GetDataRange(dr))
{
DWORD dwPlotID;
if(dr.GetData(DRR_GET_DEPENDENT | DRR_NO_FACTORS, 0, &dwPlotID, NULL, &vy, &vx) < 0)
{
printf("get data failed GetData");
return;
}
}
vector vSmooth;
vSmooth.SetSize(vy.GetSize());
//do Savitzky-Golay smoothing, Left=Right=7, quadratic
int nRet = ocmath_smooth(vy.GetSize(), vy, vSmooth, 3,SMOOTH_SG, EDGEPAD_NONE, 3, 2);
//new a worksheet to put the result
Worksheet wks;
wks.Create("Smooth");
wks.SetSize(-1, 2);
wks.SetColDesignations("XY");
DataRange drOut;
drOut.Add("X", wks, 0, 0, -1, 0);
drOut.Add("Y", wks, 0, 1, -1, 1);
drOut.SetData(&vSmooth, &vx);
//plot the curve after smoothing
int nPlot = gl.AddPlot(drOut, IDM_PLOT_LINE);
dp = gl.DataPlots(nPlot);
dp.SetColor(1);
}
origin.h
|
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|
http://spie.org/Publications/Journal/10.1117/1.JMI.3.4.043503
|
Share Email Print
### Journal of Medical Imaging
Noise performance of low-dose CT: comparison between an energy integrating detector and a photon counting detector using a whole-body research photon counting CT scanner
Author(s): Zhicong Yu; Shuai Leng; Steffen Kappler; Katharina Hahn; Zhoubo Li; Ahmed F. Halaweish; Andre Henning; Cynthia H. McCollough
Format Member Price Non-Member Price
PDF \$20.00 \$25.00
Paper Abstract
Photon counting detector (PCD)-based computed tomography (CT) is an emerging imaging technique. Compared to conventional energy integrating detector (EID)-based CT, PCD-CT is able to exclude electronic noise that may severely impair image quality at low photon counts. This work focused on comparing the noise performance at low doses between the PCD and EID subsystems of a whole-body research PCD-CT scanner, both qualitatively and quantitatively. An anthropomorphic thorax phantom was scanned, and images of the shoulder portion were reconstructed. The images were visually and quantitatively compared between the two subsystems in terms of streak artifacts, an indicator of the impact of electronic noise. Furthermore, a torso-shaped water phantom was scanned using a range of tube currents. The product of the noise and the square root of the tube current was calculated, normalized, and compared between the EID and PCD subsystems. Visual assessment of the thorax phantom showed that electronic noise had a noticeably stronger degrading impact in the EID images than in the PCD images. The quantitative results indicated that in low-dose situations, electronic noise had a noticeable impact (up to a 5.8% increase in magnitude relative to quantum noise) on the EID images, but negligible impact on the PCD images.
Paper Details
Date Published: 14 December 2016
PDF: 6 pages
J. Med. Imag. 3(4) 043503 doi: 10.1117/1.JMI.3.4.043503
Published in: Journal of Medical Imaging Volume 3, Issue 4
Show Author Affiliations
Zhicong Yu, Mayo Clinic (United States)
Shuai Leng, Mayo Clinic (United States)
Steffen Kappler, Siemens Healthcare (Germany)
Katharina Hahn, Siemens Healthineers (Germany)
Zhoubo Li, Mayo Clinic (United States)
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https://www.science.gov/topicpages/o/open+bps+wall.html
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#### Sample records for open bps wall
1. BPS domain walls in {N}=4 supergravity and dual flows
NASA Astrophysics Data System (ADS)
Cassani, Davide; Dall'Agata, Gianguido; Faedo, Anton F.
2013-03-01
We establish the conditions for supersymmetric domain wall solutions to {N}=4 gauged supergravity in five dimensions. These read as BPS first-order equations for the warp factor and the scalar fields, driven by a superpotential and supplemented by a set of constraints that we specify in detail. Then we apply our results to certain consistent truncations of IIB supergravity, thus exploring their dual field theory renormalization group flows. We find a universal flow deforming superconformal theories on D3-branes at Calabi-Yau cones. Moreover, we obtain a superpotential for the solution corresponding to the baryonic branch of the Klebanov-Strassler theory, as well as the superpotential for the flow describing D3 and wrapped D5-branes on the resolved conifold.
2. Domain Walls, near-BPS Bubbles and Probabilities in the Landscape
SciTech Connect
Ceresole, Anna; Dall'Agata, Gianguido; Giryavets, Alexander; Kallosh, Renata; Linde, Andrei; /Stanford U., Phys. Dept.
2006-06-27
We develop a theory of static BPS domain walls in stringy landscape and present a large family of BPS walls interpolating between different supersymmetric vacua. Examples include KKLT models, STU models, type IIB multiple flux vacua, and models with several Minkowski and AdS vacua. After the uplifting, some of the vacua become dS, whereas some others remain AdS. The near-BPS walls separating these vacua may be seen as bubble walls in the theory of vacuum decay. As an outcome of our investigation of the BPS walls, we found that the decay rate of dS vacua to a collapsing space with a negative vacuum energy can be quite large. The parts of space that experience a decay to a collapsing space, or to a Minkowski vacuum, never return back to dS space. The channels of irreversible vacuum decay serve as sinks for the probability flow. The existence of such sinks is a distinguishing feature of the landscape. We show that it strongly affects the probability distributions in string cosmology.
3. Exact BPS domain walls at finite gauge coupling
NASA Astrophysics Data System (ADS)
Blaschke, Filip
2017-01-01
Bogomol'nyi-Prasad-Sommerfield solitons in models with spontaneously broken gauge symmetry have been intensively studied at the infinite gauge coupling limit, where the governing equation-the so-called master equation-is exactly solvable. Except for a handful of special solutions, the standing impression is that analytic results at finite coupling are generally unavailable. The aim of this paper is to demonstrate, using domain walls in Abelian-Higgs models as the simplest example, that exact solitons at finite gauge coupling can be readily obtained if the number of Higgs fields (N) is large enough. In particular, we present a family of exact solutions, describing N domain walls at arbitrary positions in models with at least N≥2N+1. We have also found that adding together any pair of solutions can produce a new exact solution if the combined tension is below a certain limit.
4. BPS States, Crystals, and Matrices
DOE PAGES
Sułkowski, Piotr
2011-01-01
We review free fermion, melting crystal, and matrix model representations of wall-crossing phenomena on local, toric Calabi-Yau manifolds. We consider both unrefined and refined BPS counting of closed BPS states involving D2- and D0-branes bound to a D6-brane, as well as open BPS states involving open D2-branes ending on an additional D4-brane. Appropriate limit of these constructions provides, among the others, matrix model representation of refined and unrefined topological string amplitudes.
5. The structure of BPS spectra
NASA Astrophysics Data System (ADS)
Longhi, Pietro
In this thesis we develop and apply novel techniques for analyzing BPS spectra of supersymmetric quantum field theories of class S. By a combination of wall-crossing, spectral networks and quiver methods we explore the BPS spectra of higher rank four-dimensional N = 2 super Yang-Mills, uncovering surprising new phenomena. Focusing on the SU(3) case, we prove the existence of wild BPS spectra in field theory, featuring BPS states of higher spin whose degeneracies grow exponentially with the energy. The occurrence of wild BPS states is surprising because it appears to be in tension with physical expectations on the behavior of the entropy as a function of the energy scale. The solution to this puzzle comes from realizing that the size of wild BPS states grows rapidly with their mass, and carefully analyzing the volume-dependence of the entropy of BPS states. We also find some interesting structures underlying wild BPS spectra, such as a Regge-like relation between the maximal spin of a BPS multiplet and the square of its mass, and the existence of a universal asymptotic distribution of spin-j irreps within a multiplet of given charge. We also extend the spectral networks construction by introducing a refinement in the topological classification of 2d-4d BPS states, and identifying their spin with a topological invariant known as the "writhe of soliton paths". A careful analysis of the 2d-4d wall-crossing behavior of this refined data reveals that it is described by motivic Kontsevich-Soibelman transformations, controlled by the Protected Spin Character, a protected deformation of the BPS index encoding the spin of BPS states. Our construction opens the way for the systematic study of refined BPS spectra in class S theories. We apply it to several examples, including ones featuring wild BPS spectra, where we find an interesting relation between spectral networks and certain functional equations. For class S theories of A 1 type, we derive an alternative technique for
6. Liposomal Bladder Instillations for IC/BPS: an Open-Label Clinical Evaluation
PubMed Central
Peters, Kenneth M; Hasenau, Deborah; Killinger, Kim A; Chancellor, Michael B; Anthony, Michele; Kaufman, Jonathan
2015-01-01
Purpose Intravesical instillation of liposomes is a potentially new therapeutic option for subjects with interstitial cystitis/bladder pain syndrome (IC/BPS). The aim of this study was to explore the safety and clinical outcomes of 4 weekly instillations of sphingomyelin liposomes in an open-label cohort of subjects with IC/BPS. Methods A total of fourteen symptomatic IC/BPS subjects were treated with intravesical liposomes once a week for 4 weeks. Safety measurements included lab specimen collection, vital signs, post void residual (PVR), and assessment of adverse events (AEs). Efficacy measurements included pain visual analog scales (VAS), voiding diaries, global response assessments (GRAs), and O'Leary-Sant Interstitial Cystitis Symptom and Problem Indices (ICSI and ICPI). Results No treatment-related adverse events (AE) were reported at any time over the course of the study. Urgency VAS scores significantly decreased at 4 weeks (p=0.0029) and 8 weeks (p=0.0112) post-treatment. Pain VAS scores significantly decreased at 4 weeks post-treatment (p=0.0073). Combined ICSI and ICPI scores improved significantly at 4 weeks and 8 weeks (p=0.002 for both time points) post-treatment. Responses to GRA showed improvement at 4 weeks post- instillation. No significant decrease in urinary frequency was found. Conclusion Sphingomyelin liposome instillations were well tolerated in subjects with IC/BPS with no AEs attributed to the test article. Treatment was associated with improvements in pain, urinary urgency, and overall symptom scores. Placebo controlled clinical trials are needed to assess this potential therapy for IC/BPS. PMID:25209396
7. BPS states in string theory
NASA Astrophysics Data System (ADS)
Andriyash, Evgeny
In this thesis we discuss a number of interesting and important properties of BPS states in string theory. We study wall-crossing behavior of BPS states at large volume limit and implications of it for the OSV conjecture. We find that the weak topological coupling OSV conjecture can be true at most in a special chamber of the Kahler cone. We also clarify an interesting puzzle arising in the description of BPS states on the Higgs branch of supersymmetic quantum mechanics. Using methods of toric geometry we compute Hilbert spaces of BPS states on the compactified Higgs branch and arrive at completely consistent picture of spatial Spin(3) structure of those spaces. We introduce new kinds of walls, called Bound State Transformation(BST) walls, in the moduli space across which the nature of BPS bound states changes but the index remains continuous. These walls are necessary to explain the continuity of BPS index. BPS states can undergo recombination, conjugation or hybrids of the two when crossing a BST wall. Conjugation phenomenon happens near singularities in the moduli space and we relate massless spectra of BPS states at such singularities to monodromies around them. In cases when massless vector BPS particles are present we find new constraints on the spectrum and in particular predict the existence of magnetic monopoles becoming massless at such singularities. We give a simple physical derivation of the Kontsevich-Soibelman wall-crossing formula. Considering galaxy-like configurations of BPS particles with a central supermassive black hole with a number of stellar BPS systems around it we derive a consistency requirement on the partition function of such BPS galaxies. This requirement turns out to be nothing but Kontsevich-Soibelman wall-crossing formula. Our approach gives a generalization of the formula for the case when massless BPS particles are present.
8. Multi-scalar tachyon potential on non-BPS domain walls
NASA Astrophysics Data System (ADS)
Brito, F. A.; Jesuíno, H. S.
2010-07-01
We have considered the multi-scalar and multi-tachyon fields living on a 3d domain wall embedded in a 5d dimensional Minkowski spacetime. The effective action for such a domain wall can be found by integrating out the normal m odes as vibrating modes around the domain wall solution of a truncated 5d supergravity action. The multi-scalar tachyon potential is good enough to modeling assisted inflation scenario with multi-tachyon fields. The tachyon condensation is also briefly addressed.
9. BpsR Modulates Bordetella Biofilm Formation by Negatively Regulating the Expression of the Bps Polysaccharide
PubMed Central
Conover, Matt S.; Redfern, Crystal J.; Ganguly, Tridib; Sukumar, Neelima; Sloan, Gina; Mishra, Meenu
2012-01-01
Bordetella bacteria are Gram-negative respiratory pathogens of animals, birds, and humans. A hallmark feature of some Bordetella species is their ability to efficiently survive in the respiratory tract even after vaccination. Bordetella bronchiseptica and Bordetella pertussis form biofilms on abiotic surfaces and in the mouse respiratory tract. The Bps exopolysaccharide is one of the critical determinants for biofilm formation and the survival of Bordetella in the murine respiratory tract. In order to gain a better understanding of regulation of biofilm formation, we sought to study the mechanism by which Bps expression is controlled in Bordetella. Expression of bpsABCD (bpsA-D) is elevated in biofilms compared with levels in planktonically grown cells. We found that bpsA-D is expressed independently of BvgAS. Subsequently, we identified an open reading frame (ORF), BB1771 (designated here bpsR), that is located upstream of and in the opposite orientation to the bpsA-D locus. BpsR is homologous to the MarR family of transcriptional regulators. Measurement of bpsA and bpsD transcripts and the Bps polysaccharide levels from the wild-type and the ΔbpsR strains suggested that BpsR functions as a repressor. Consistent with enhanced production of Bps, the bpsR mutant displayed considerably more structured biofilms. We mapped the bpsA-D promoter region and showed that purified BpsR protein specifically bound to the bpsA-D promoter. Our results provide mechanistic insights into the regulatory strategy employed by Bordetella for control of the production of the Bps polysaccharide and biofilm formation. PMID:22056934
10. BpsR modulates Bordetella biofilm formation by negatively regulating the expression of the Bps polysaccharide.
PubMed
Conover, Matt S; Redfern, Crystal J; Ganguly, Tridib; Sukumar, Neelima; Sloan, Gina; Mishra, Meenu; Deora, Rajendar
2012-01-01
Bordetella bacteria are Gram-negative respiratory pathogens of animals, birds, and humans. A hallmark feature of some Bordetella species is their ability to efficiently survive in the respiratory tract even after vaccination. Bordetella bronchiseptica and Bordetella pertussis form biofilms on abiotic surfaces and in the mouse respiratory tract. The Bps exopolysaccharide is one of the critical determinants for biofilm formation and the survival of Bordetella in the murine respiratory tract. In order to gain a better understanding of regulation of biofilm formation, we sought to study the mechanism by which Bps expression is controlled in Bordetella. Expression of bpsABCD (bpsA-D) is elevated in biofilms compared with levels in planktonically grown cells. We found that bpsA-D is expressed independently of BvgAS. Subsequently, we identified an open reading frame (ORF), BB1771 (designated here bpsR), that is located upstream of and in the opposite orientation to the bpsA-D locus. BpsR is homologous to the MarR family of transcriptional regulators. Measurement of bpsA and bpsD transcripts and the Bps polysaccharide levels from the wild-type and the ΔbpsR strains suggested that BpsR functions as a repressor. Consistent with enhanced production of Bps, the bpsR mutant displayed considerably more structured biofilms. We mapped the bpsA-D promoter region and showed that purified BpsR protein specifically bound to the bpsA-D promoter. Our results provide mechanistic insights into the regulatory strategy employed by Bordetella for control of the production of the Bps polysaccharide and biofilm formation.
11. Semiclassical framed BPS states
NASA Astrophysics Data System (ADS)
Moore, Gregory W.; Royston, Andrew B.; Van den Bleeken, Dieter
2016-07-01
We provide a semiclassical description of framed BPS states in four-dimensional {N}=2 super Yang-Mills theories probed by 't Hooft defects, in terms of a supersymmetric quantum mechanics on the moduli space of singular monopoles. Framed BPS states, like their ordinary counterparts in the theory without defects, are associated with the L 2 kernel of certain Dirac operators on moduli space, or equivalently with the L 2 cohomology of related Dolbeault operators. The Dirac/Dolbeault operators depend on two Cartan-valued Higgs vevs. We conjecture a map between these vevs and the Seiberg-Witten special coordinates, consistent with a one-loop analysis and checked in examples. The map incorporates all perturbative and nonperturbative corrections that are relevant for the semiclassical construction of BPS states, over a suitably defined weak coupling regime of the Coulomb branch. We use this map to translate wall crossing formulae and the no-exotics theorem to statements about the Dirac/Dolbeault operators. The no-exotics theorem, concerning the absence of nontrivial SU(2) R representations in the BPS spectrum, implies that the kernel of the Dirac operator is chiral, and further translates into a statement that all L 2 cohomology of the Dolbeault operator is concentrated in the middle degree. Wall crossing formulae lead to detailed predictions for where the Dirac operators fail to be Fredholm and how their kernels jump. We explore these predictions in nontrivial examples. This paper explains the background and arguments behind the results announced in the short note [1].
12. Line defects and (framed) BPS quivers
NASA Astrophysics Data System (ADS)
Cirafici, Michele
2013-11-01
The BPS spectrum of certain = 2 supersymmetric field theories can be determined algebraically by studying the representation theory of BPS quivers. We introduce methods based on BPS quivers to study line defects. The presence of a line defect opens up a new BPS sector: framed BPS states can be bound to the defect. The defect can be geometrically described in terms of laminations on a curve. To a lamination we associate certain elements of the Leavitt path algebra of the BPS quiver and use them to compute the framed BPS spectrum. We also provide an alternative characterization of line defects by introducing framed BPS quivers. Using the theory of (quantum) cluster algebras, we derive an algorithm to compute the framed BPS spectra of new defects from known ones. Line defects are generated from a framed BPS quiver by applying certain sequences of mutation operations. Framed BPS quivers also behave nicely under a set of "cut and join" rules, which can be used to study how = 2 systems with defects couple to produce more complicated ones. We illustrate our formalism with several examples.
13. 10. Detail view, greenhouse, south wall. These groundlevel openings were ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
10. Detail view, greenhouse, south wall. These ground-level openings were part of the original heating system used to warm the greenhouse. The openings were likely related to the flues, while a larger opening to the west (not in photograph) contained an exterior-fed iron stove. - John Bartram House & Garden, Greenhouse, 54th Street & LIndbergh Boulevard, Philadelphia, Philadelphia County, PA
14. 13. Greenhouse, east elevation. The boardandbatten wall covers an opening ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
13. Greenhouse, east elevation. The board-and-batten wall covers an opening that was originally fitted with windows which allowed sunlight into the greenhouse. - John Bartram House & Garden, Greenhouse, 54th Street & LIndbergh Boulevard, Philadelphia, Philadelphia County, PA
15. 19. View looking N at mill wall ruins with open ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
19. View looking N at mill wall ruins with open end of purging house in background. - Hacienda Azucarera La Esperanza, Mill (Ruins), 2.65 miles North of PR Route 2 Bridge Over Manati River, Manati, Manati Municipio, PR
16. Sequencing BPS spectra
NASA Astrophysics Data System (ADS)
Gukov, Sergei; Nawata, Satoshi; Saberi, Ingmar; Stošić, Marko; Sułkowski, Piotr
2016-03-01
This paper provides both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explain from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincaré polynomials in numerous examples. Among these structural properties is a novel "sliding" property, which can be explained by using (refined) modular S-matrix. This leads to the identification of modular transformations in Chern-Simons theory and 3d {N}=2 theory via the 3d/3d correspondence. Lastly, we introduce the notion of associated varieties as classical limits of recursion relations of colored superpolynomials of links, and study their properties.
17. Sequencing BPS spectra
SciTech Connect
Gukov, Sergei; Nawata, Satoshi; Saberi, Ingmar; Stošić, Marko; Sułkowski, Piotr
2016-03-02
In this article, we provide both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explain from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincar e polynomials in numerous examples. Among these structural properties is a novel "sliding" property, which can be explained by using (re fined) modular S-matrix. This leads to the identi fication of modular transformations in Chern-Simons theory and 3d N = 2 theory via the 3d/3d correspondence. In conclusion, we introduce the notion of associated varieties as classical limits of recursion relations of colored superpolynomials of links, and study their properties.
18. Sequencing BPS spectra
DOE PAGES
Gukov, Sergei; Nawata, Satoshi; Saberi, Ingmar; ...
2016-03-02
In this article, we provide both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explainmore » from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincar e polynomials in numerous examples. Among these structural properties is a novel "sliding" property, which can be explained by using (re fined) modular S-matrix. This leads to the identi fication of modular transformations in Chern-Simons theory and 3d N = 2 theory via the 3d/3d correspondence. In conclusion, we introduce the notion of associated varieties as classical limits of recursion relations of colored superpolynomials of links, and study their properties.« less
19. Crystal Melting and Wall Crossing Phenomena
NASA Astrophysics Data System (ADS)
Yamazaki, Masahito
2010-02-01
This paper summarizes recent developments in the theory of Bogomol'nyi-Prasad-Sommerfield (BPS) state counting and the wall crossing phenomena, emphasizing in particular the role of the statistical mechanical model of crystal melting. This paper is divided into two parts, which are closely related to each other. In the first part, we discuss the statistical mechanical model of crystal melting counting BPS states. Each of the BPS state contributing to the BPS index is in one-to-one correspondence with a configuration of a molten crystal, and the statistical partition function of the melting crystal gives the BPS partition function. We also show that smooth geometry of the Calabi-Yau manifold emerges in the thermodynamic limit of the crystal. This suggests a remarkable interpretation that an atom in the crystal is a discretization of the classical geometry, giving an important clue as to the geometry at the Planck scale.In the second part we discuss the wall crossing phenomena. Wall crossing phenomena states that the BPS index depends on the value of the moduli of the Calabi-Yau manifold, and jumps along real codimension one subspaces in the moduli space. We show that by using type IIA/M-theory duality, we can provide a simple and an intuitive derivation of the wall crossing phenomena, furthermore clarifying the connection with the topological string theory. This derivation is consistent with another derivation from the wall crossing formula, motivated by multi-centered BPS extremal black holes. We also explain the representation of the wall crossing phenomena in terms of crystal melting, and the generalization of the counting problem and the wall crossing to the open BPS invariants.
20. Crystal Melting and Wall Crossing Phenomena
NASA Astrophysics Data System (ADS)
Yamazaki, Masahito
This paper summarizes recent developments in the theory of Bogomol'nyi-Prasad-Sommerfield (BPS) state counting and the wall crossing phenomena, emphasizing in particular the role of the statistical mechanical model of crystal melting. This paper is divided into two parts, which are closely related to each other. In the first part, we discuss the statistical mechanical model of crystal melting counting BPS states. Each of the BPS states contributing to the BPS index is in one-to-one correspondence with a configuration of a molten crystal, and the statistical partition function of the melting crystal gives the BPS partition function. We also show that smooth geometry of the Calabi-Yau manifold emerges in the thermodynamic limit of the crystal. This suggests a remarkable interpretation that an atom in the crystal is a discretization of the classical geometry, giving an important clue as such to the geometry at the Planck scale. In the second part, we discuss the wall crossing phenomena. Wall crossing phenomena states that the BPS index depends on the value of the moduli of the Calabi-Yau manifold, and jumps along real codimension one subspaces in the moduli space. We show that by using type IIA/M-theory duality, we can provide a simple and an intuitive derivation of the wall crossing phenomena, furthermore clarifying the connection with the topological string theory. This derivation is consistent with another derivation from the wall crossing formula, motivated by multicentered BPS extremal black holes. We also explain the representation of the wall crossing phenomena in terms of crystal melting, and the generalization of the counting problem and the wall crossing to the open BPS invariants.
1. BEDROOM 1 SHOWING THE OPENING IN THE EXTERIOR WALL FOR ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
BEDROOM 1 SHOWING THE OPENING IN THE EXTERIOR WALL FOR AN AIR CONDITIONER. VIEW FACING NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, U-Shaped Three-Bedroom Duplex Type 3, Acacia Road, Birch Circle, and Cedar Drive, Pearl City, Honolulu County, HI
2. Double Mine Building (N) wall showing clerestory slot windows opening ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
Double Mine Building (N) wall showing clerestory slot windows opening above level of main roof. Note structure is built on poured concrete foundation partly buried in hillside; view in southeast - Fort McKinley, Double Mine Building, East side of East Side Drive, approximately 125 feet south of Weymouth Way, Great Diamond Island, Portland, Cumberland County, ME
3. BPS dyons and Hesse flow
NASA Astrophysics Data System (ADS)
Van den Bleeken, Dieter
2012-02-01
We revisit BPS solutions to classical N = 2 low energy effective gauge theories. It is shown that the BPS equations can be solved in full generality by the introduction of a Hesse potential, a symplectic analog of the holomorphic prepotential. We explain how for non-spherically symmetric, non-mutually local solutions, the notion of attractor flow generalizes to gradient flow with respect to the Hesse potential. Furthermore we show that in general there is a non-trivial magnetic complement to this flow equation that is sourced by the momentum current in the solution.
4. 29 CFR 1910.23 - Guarding floor and wall openings and holes.
Code of Federal Regulations, 2011 CFR
2011-07-01
... chute floor opening shall be guarded by one of the following: (i) Hinged floor opening cover of standard... use. Where operating conditions necessitate the feeding of material into any hatchway or chute opening... specifications. (2) Every chute wall opening from which there is a drop of more than 4 feet shall be guarded...
5. The Open Classroom: Were Schools Without Walls Just Another Fad?
ERIC Educational Resources Information Center
Cuban, Larry
2004-01-01
The open-classroom movement originated in British public elementary schools after World War II. American educators who adopted the trend viewed informal education--or, as they came to call it, open classrooms or open education--as an answer to both the American education system's critics and the problems of U.S. society. Open classrooms' focus on…
6. 29 CFR 1910.23 - Guarding floor and wall openings and holes.
Code of Federal Regulations, 2013 CFR
2013-07-01
... someone or shall be protected by removable standard railings. (7) Every temporary floor opening shall have..., a standard toe board shall be provided. (4) Every temporary wall opening shall have adequate guards... exclusively for special purposes (such as oiling, shafting, or filling tank cars) may have the railing on...
7. Primary closure of the abdominal wall after "open abdomen" situation.
PubMed
Kääriäinen, M; Kuokkanen, H
2013-01-01
"Open abdomen" is a strategy used to avoid or treat abdominal compartment syndrome. It has reduced mortality both in trauma and non-trauma abdominal catastrophes but also has created a challenging clinical problem. Traditionally, open abdomen is closed in two phases; primarily with a free skin graft and later with a flap reconstruction. A modern trend is to close the abdomen within the initial hospitalization. This requires multi-professional co-operation. Temporary abdominal closure methods, e.g. negative pressure wound therapy alone or combined with mesh-mediated traction, have been developed to facilitate direct fascial closure. Components separation technique, mesh reinforcement or bridging of the fascial defect with mesh and perforator saving skin undermining can be utilized in the final closure if needed. These techniques can be combined. Choice of the treatment depends on the condition of the patient and size of the fascia and skin defect, and the state of the abdominal contents. In this paper we review the literature on the closure of an open abdomen and present the policy used in our institution in the open abdomen situations.
8. HOT CELL BUILDING, TRA632, INTERIOR. OPEN CORRIDOR ALONG SOUTH WALL ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
HOT CELL BUILDING, TRA-632, INTERIOR. OPEN CORRIDOR ALONG SOUTH WALL OF BUILDING. CAMERA IS NEAR HOT CELL NO. 1, FACES WEST TOWARDS WALL OF TEST-TRAIN ASSEMBLY (TRA-632A). NOTE MOTORIZED RAIL CRANE ABOVE STAIRWAY. INL NEGATIVE NO. HD46-29-3. Mike Crane, Photographer, 2/2005 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID
9. Instantaneous response of elastic thin-walled structures with arbitrary open cross section to rapid heating
NASA Technical Reports Server (NTRS)
Chen, Xiaoqin; Mohan, Ram V.; Tamma, Kumar K.
1992-01-01
A generalized modeling and analysis approach of thermally-induced coupled vibrations of elastic thin-walled configurations with arbitrary open cross sections are presented in conjunction with a unified implicit transient methodology. Limited research appears in literature which takes into account the influence of rapid thermal heating effects on structures involving various forms of coupling. As a consequence, the dynamic response of such thin-walled structures of arbitrary open cross section due to rapid heating are described here. Effects involving triple, double, and no coupling between bending and torsional vibrations caused by sudden heating on these structures are examined. Numerical test cases are presented which describe the influence of sudden heating on elastic thin-walled structures of arbitrary open cross sections.
10. Microbubbles and Blood Brain Barrier Opening: A Numerical Study on Acoustic Emissions and Wall Stress Predictions
PubMed Central
Goertz, David E.; Hynynen, Kullervo
2015-01-01
Focused ultrasound with microbubbles is an emerging technique for blood brain barrier (BBB) opening. Here, a comprehensive theoretical model of a bubble-fluid-vessel system has been developed which accounts for the bubble’s non-spherical oscillations inside a microvessel, and its resulting acoustic emissions. Numerical simulations of unbound and confined encapsulated bubbles were performed to evaluate the effect of the vessel wall on acoustic emissions and vessel wall stresses. Using a Marmottant shell model, the normalized second harmonic to fundamental emissions first decreased as a function of pressure (>50 kPa) until reaching a minima ("transition point") at which point they increased. The transition point of unbound compared to confined bubble populations occurred at different pressures and was associated with an accompanying increase in shear and circumferential wall stresses. As the wall stresses depend on the bubble to vessel wall distance, the stresses were evaluated for bubbles with their wall at a constant distance to a flat wall. As a result, the wall stresses were bubble size and frequency dependent and the peak stress values induced by bubbles larger than resonance remained constant versus frequency at a constant mechanical index. PMID:25546853
11. 4d Spectra from BPS Quiver Dualities
NASA Astrophysics Data System (ADS)
Espahbodi, Sam
We attack the question of BPS occupancy in a wide class of 4d N = 2 quantum field theories. We first review the Seiberg-Witten approach to finding the low energy Wilsonian effective action actions of such theories. In particular, we analyze the case of Gaiotto theories, which provide a large number of non-trivial examples in a unified framework. We then turn to understanding the massive BPS spectrum of such theories, and in particular their relation to BPS quivers. We present a purely 4d characterization of BPS quivers, and explain how a quiver's representation theory encodes the solution to the BPS occupancy problem. Next, we derive a so called mutation method, based on exploiting quiver dualities, to solve the quiver's representation theory. This method makes previously intractable calculations nearly trivial in many examples. As a particular highlight, we apply our methods to understand strongly coupled chambers in ADE SYM gauge theories with matter. Following this, we turn to the general story of quivers for theories of the Gaiotto class. We present a geometric approach to attaining quivers for the rank 2 theories, leading to a very elegant solution which includes a specification of quiver superpotentials. Finally, we solve these theories by an unrelated method based on gauging flavor symmetries in their various dual weakly coupled Lagrangian descriptions. After seeing that this method agrees in the rank 2 case, we will apply our new approach to the case of rank n.
12. Near BPS skyrmions and restricted harmonic maps
NASA Astrophysics Data System (ADS)
Speight, J. M.
2015-06-01
Motivated by a class of near BPS Skyrme models introduced by Adam, Sánchez-Guillén and Wereszczyński, the following variant of the harmonic map problem is introduced: a map φ :(M, g) →(N, h) between Riemannian manifolds is restricted harmonic if it locally extremizes E2 on its SDiff(M) orbit, where SDiff(M) denotes the group of volume preserving diffeomorphisms of (M, g), and E2 denotes the Dirichlet energy. It is conjectured that near BPS skyrmions tend to restricted harmonic maps in the BPS limit. It is shown that φ is restricted harmonic if and only if φ∗ h has exact divergence, and a linear stability theory of restricted harmonic maps is developed, from which it follows that all weakly conformal maps are stable restricted harmonic. Examples of restricted harmonic maps in every degree class R3 → SU(2) and R2 →S2 are constructed. It is shown that the axially symmetric BPS skyrmions on which all previous analytic studies of near BPS Skyrme models have been based, are not restricted harmonic, casting doubt on the phenomenological predictions of such studies. The problem of minimizing E2 for φ :Rk → N over all linear volume preserving diffeomorphisms is solved explicitly, and a deformed axially symmetric family of Skyrme fields constructed which are candidates for approximate near BPS skyrmions at low baryon number. The notion of restricted harmonicity is generalized to restricted F-criticality where F is any functional on maps (M, g) →(N, h) which is, in a precise sense, geometrically natural. The case where F is a linear combination of E2 and E4, the usual Skyrme term, is studied in detail, and it is shown that inverse stereographic projection R3 →S3 ≡ SU(2) is stable restricted F-critical for every such F.
13. Open-ended Coaxial Cavities with Corrugated Inner and Outer Walls
NASA Astrophysics Data System (ADS)
Ioannidis, Zisis C.; Avramidis, Konstantinos A.; Tigelis, Ioannis G.
2015-05-01
In this work an open-ended coaxial cavity with a corrugated insert and a relatively small number of corrugations on the outer wall is studied. In particular, the Spatial Harmonics Method (SHM) is employed in order to derive the TE modes characteristic equation, which is then solved by truncation for the calculation of the corresponding eigenvalues. Special care is given in the expansion functions used in order to avoid numerical instabilities in the calculation of high-order spatial terms. Various cases of outer wall corrugations are studied numerically in order to identify the effect of the outer corrugations and understand the mode coupling mechanism.
14. The Skyrme Model in the BPS Limit
NASA Astrophysics Data System (ADS)
Adam, C.; Naya, C.; Sánchez-Guillén, J.; Vazquez, R.; Wereszczyński, A.
In this review, we summarize the main features of the BPS Skyrme model which provides a physically well-motivated idealization of atomic nuclei and nuclear matter: (1) it leads to zero binding energies for classical solitons (while realistic binding energies emerge owing to the semiclassical corrections, the Coulomb interaction and isospin breaking); (2) it describes a perfect non-barotropic fluid already at the microscopic (field theoretical) level which allows to study thermodynamics beyond the mean-field limit. These properties allow for an approximate but analytical calculation of binding energies of the most abundant nuclei, for a determination of the equation of state of skyrmionic matter (both in the full field theory and in a mean-field approximation) as well as the description of neutron stars as Skyrme solitons with a very good agreement with available observational data. All these results suggest that the proper low energy effective model of QCD should be close to the BPS Skyrme model in a certain sense (a "near-BPS Skyrme model"), with a prominent role played by the BPS part.
15. High Q BPS Monopole Bags are Urchins
NASA Astrophysics Data System (ADS)
Evslin, Jarah; Gudnason, Sven Bjarke
2014-01-01
It has been known for 30 years that 't Hooft-Polyakov monopoles of charge Q greater than one cannot be spherically symmetric. Five years ago, Bolognesi conjectured that, at some point in their moduli space, BPS monopoles can become approximately spherically symmetric in the high Q limit. In this paper, we determine the sense in which this conjecture is correct. We consider an SU(2) gauge theory with an adjoint scalar field, and numerically find configurations with Q units of magnetic charge and a mass which is roughly linear in Q, for example, in the case Q = 81 we present a configuration whose energy exceeds the BPS bound by about 54%. These approximate solutions are constructed by gluing together Q cones, each of which contains a single unit of magnetic charge. In each cone, the energy is largest in the core, and so a constant energy density surface contains Q peaks and thus resembles a sea urchin.
16. Biomass Production System (BPS) Plant Growth Unit
NASA Astrophysics Data System (ADS)
Morrow, R. C.; Crabb, T. M.
The Biomass Production System (BPS) was developed under the Small Business Innovative Research (SBIR) program to meet science, biotechnology and commercial plant growth needs in the Space Station era. The BPS is equivalent in size to a double middeck locker, but uses it's own custom enclosure with a slide out structure to which internal components mount. The BPS contains four internal growth chambers, each with a growing volume of more than 4 liters. Each of the growth chambers has active nutrient delivery, and independent control of temperature, humidity, lighting, and CO2 set-points. Temperature control is achieved using a thermoelectric heat exchanger system. Humidity control is achieved using a heat exchanger with a porous interface which can both humidify and dehumidify. The control software utilizes fuzzy logic for nonlinear, coupled temperature and humidity control. The fluorescent lighting system can be dimmed to provide a range of light levels. CO2 levels are controlled by injecting pure CO2 to the system based on input from an infrared gas analyzer. The unit currently does not scrub CO2, but has been designed to accept scrubber cartridges. In addition to providing environmental control, a number of features are included to facilitate science. The BPS chambers are sealed to allow CO2 and water vapor exchange measurements. The plant chambers can be removed to allow manipulation or sampling of specimens, and each chamber has gas/fluid sample ports. A video camera is provided for each chamber, and frame-grabs and complete environmental data for all science and hardware system sensors are stored on an internal hard drive. Data files can also be transferred to 3.5-inch disks using the front panel disk drive
17. Biomass Production System (BPS) plant growth unit.
PubMed
Morrow, R C; Crabb, T M
2000-01-01
The Biomass Production System (BPS) was developed under the Small Business Innovative Research (SBIR) program to meet science, biotechnology and commercial plant growth needs in the Space Station era. The BPS is equivalent in size to a double middeck locker, but uses its own custom enclosure with a slide out structure to which internal components mount. The BPS contains four internal growth chambers, each with a growing volume of more than 4 liters. Each of the growth chambers has active nutrient delivery, and independent control of temperature, humidity, lighting, and CO2 set-points. Temperature control is achieved using a thermoelectric heat exchanger system. Humidity control is achieved using a heat exchanger with a porous interface which can both humidify and dehumidify. The control software utilizes fuzzy logic for nonlinear, coupled temperature and humidity control. The fluorescent lighting system can be dimmed to provide a range of light levels. CO2 levels are controlled by injecting pure CO2 to the system based on input from an infrared gas analyzer. The unit currently does not scrub CO2, but has been designed to accept scrubber cartridges. In addition to providing environmental control, a number of features are included to facilitate science. The BPS chambers are sealed to allow CO2 and water vapor exchange measurements. The plant chambers can be removed to allow manipulation or sampling of specimens, and each chamber has gas/fluid sample ports. A video camera is provided for each chamber, and frame-grabs and complete environmental data for all science and hardware system sensors are stored on an internal hard drive. Data files can also be transferred to 3.5-inch disks using the front panel disk drive.
18. Argon adsorption in open-ended single-wall carbon nanotubes
SciTech Connect
Rols, S.; Johnson, M.R.; Zeppenfeld, P.; Bienfait, M.; Vilches, O.E.; Schneble, J.
2005-04-15
Thermodynamic and neutron-diffraction measurements combined with molecular dynamics simulation are used to determine the adsorption energies and the structure of argon condensed in the various adsorption sites of purified open-ended single-wall nanotube bundles. On the basis of these experiments and the simulation results, a consistent adsorption scenario has been derived. The adsorption proceeds first by the population of the walls inside the open nanotubes and the formation of one-dimensional Ar chains in the grooves at the outer surface of the bundles, followed by the filling of the remaining axial sites inside the nanotubes and the completion of a quasihexagonal monolayer on the outer surface of the bundle. The measurements also provide an estimate of the relative abundance of the various adsorption sites revealing that a major part of the adsorbed Ar is stored inside the open-ended nanotubes. Nanotube bundles generally show a certain degree of heterogeneity and some interstitial sites should be populated over a range of Ar chemical potential. However, for the sample used here, diffraction data and simulations suggest that heterogeneity is not a key feature of the bundles and there is little direct evidence of interstitial sites being populated.
19. Colloid retention at the meniscus-wall contact line in an open microchannel.
PubMed
Zevi, Yuniati; Gao, Bin; Zhang, Wei; Morales, Verónica L; Cakmak, M Ekrem; Medrano, Evelyn A; Sang, Wenjing; Steenhuis, Tammo S
2012-02-01
Colloid retention mechanisms in partially saturated porous media are currently being researched with an array of visualization techniques. These visualization techniques have refined our understanding of colloid movement and retention at the pore scale beyond what can be obtained from breakthrough experiments. One of the remaining questions is what mechanisms are responsible for colloid immobilization at the triple point where air, water, and soil grain meet. The objective of this study was to investigate how colloids are transported to the air-water-solid (AWS) contact line in an open triangular microchannel, and then retained as a function of meniscus contact angle with the wall and solution ionic strength. Colloid flow path, meniscus shape and meniscus-wall contact angle, and colloid retention at the AWS contact line were visualized and quantified with a confocal microscope. Experimental results demonstrated that colloid retention at the AWS contact line was significant when the meniscus-wall contact angle was less than 16°, but was minimal for the meniscus-wall contact angles exceeding 20°. Tracking of individual colloids and computational hydrodynamic simulation both revealed that for small contact angles (e.g., 12.5°), counter flow and flow vortices formed near the AWS contact line, but not for large contact angles (e.g., 28°). This counter flow helped deliver the colloids to the wall surface just below the contact line. In accordance with DLVO and hydrodynamic torque calculations, colloid movement may be stopped when the colloid reached the secondary minimum at the wall near the contact line. However, contradictory to the prediction of the torque analysis, colloid retention at the AWS contact line decreased with increasing ionic strength for contact angles of 10-20°, indicating that the air-water interface was involved through both counter flow and capillary force. We hypothesized that capillary force pushed the colloid through the primary energy
20. Universal BPS structure of stationary supergravity solutions
NASA Astrophysics Data System (ADS)
Bossard, Guillaume; Nicolai, Hermann; Stelle, K. S.
2009-07-01
We study asymptotically flat stationary solutions of four-dimensional supergravity theories via the associated fraktur G/fraktur H* pseudo-Riemannian non-linear sigma models in three spatial dimensions. The Noether charge Script C associated to fraktur G is shown to satisfy a characteristic equation that determines it as a function of the four-dimensional conserved charges. The matrix Script C is nilpotent for non-rotating extremal solutions. The nilpotency degree of Script C is directly related to the BPS degree of the corresponding solution when they are BPS. Equivalently, the charges can be described in terms of a Weyl spinor |Script Crangle of Spin*(2Script N), and then the characteristic equation becomes equivalent to a generalisation of the Cartan pure spinor constraint on |Script Crangle. The invariance of a given solution with respect to supersymmetry is determined by an algebraic Dirac equation' on the Weyl spinor |Script Crangle. We explicitly solve this equation for all pure supergravity theories and we characterise the stratified structure of the moduli space of asymptotically Taub-NUT black holes with respect to their BPS degree. The analysis is valid for any asymptotically flat stationary solutions for which the singularities are protected by horizons. The fraktur H*-orbits of extremal solutions are identified as Lagrangian submanifolds of nilpotent orbits of fraktur G, and so the moduli space of extremal spherically symmetric black holes is identified as a Lagrangian subvariety of the variety of nilpotent elements of fraktur g. We also generalise the notion of active duality transformations to an almost action' of the three-dimensional duality group fraktur G on asymptotically flat stationary solutions.
1. Black holes in supergravity: the non-BPS branch
SciTech Connect
Gimon, Eric; Gimon, Eric G.; Larsen, Finn; Simon, Joan
2007-10-25
We construct extremal, spherically symmetric black hole solutions to 4D supergravity with charge assignments that preclude BPS-saturation. In particular, we determine the ground state energy as a function of charges and moduli. We find that the mass of the non-BPS black hole remains that of a marginal bound state of four basic constituents throughout the entire moduli space and that there is always a non-zero gap above the BPS bound.
2. Lie n-algebras of BPS charges
NASA Astrophysics Data System (ADS)
Sati, Hisham; Schreiber, Urs
2017-03-01
We uncover higher algebraic structures on Noether currents and BPS charges. It is known that equivalence classes of conserved currents form a Lie algebra. We show that at least for target space symmetries of higher parameterized WZW-type sigma-models this naturally lifts to a Lie ( p + 1)-algebra structure on the Noether currents themselves. Applied to the Green-Schwarz-type action functionals for super p-brane sigma-models this yields super Lie ( p+1)-algebra refinements of the traditional BPS brane charge extensions of supersymmetry algebras. We discuss this in the generality of higher differential geometry, where it applies also to branes with (higher) gauge fields on their worldvolume. Applied to the M5-brane sigma-model we recover and properly globalize the M-theory super Lie algebra extension of 11-dimensional superisometries by 2-brane and 5-brane charges. Passing beyond the infinitesimal Lie theory we find cohomological corrections to these charges in higher analogy to the familiar corrections for D-brane charges as they are lifted from ordinary cohomology to twisted K-theory. This supports the proposal that M-brane charges live in a twisted cohomology theory.
3. Crack opening area estimates in pressurized through-wall cracked elbows under bending
SciTech Connect
Franco, C.; Gilles, P.; Pignol, M.
1997-04-01
One of the most important aspects in the leak-before-break approach is the estimation of the crack opening area corresponding to potential through-wall cracks at critical locations during plant operation. In order to provide a reasonable lower bound to the leak area under such loading conditions, numerous experimental and numerical programs have been developed in USA, U.K. and FRG and widely discussed in literature. This paper aims to extend these investigations on a class of pipe elbows characteristic of PWR main coolant piping. The paper is divided in three main parts. First, a new simplified estimation scheme for leakage area is described, based on the reference stress method. This approach mainly developed in U.K. and more recently in France provides a convenient way to account for the non-linear behavior of the material. Second, the method is carried out for circumferential through-wall cracks located in PWR elbows subjected to internal pressure. Finite element crack area results are presented and comparisons are made with our predictions. Finally, in the third part, the discussion is extended to elbows under combined pressure and in plane bending moment.
4. Numerical study of the effects of lamp configuration and reactor wall roughness in an open channel water disinfection UV reactor.
PubMed
Sultan, Tipu
2016-07-01
This article describes the assessment of a numerical procedure used to determine the UV lamp configuration and surface roughness effects on an open channel water disinfection UV reactor. The performance of the open channel water disinfection UV reactor was numerically analyzed on the basis of the performance indictor reduction equivalent dose (RED). The RED values were calculated as a function of the Reynolds number to monitor the performance. The flow through the open channel UV reactor was modelled using a k-ε model with scalable wall function, a discrete ordinate (DO) model for fluence rate calculation, a volume of fluid (VOF) model to locate the unknown free surface, a discrete phase model (DPM) to track the pathogen transport, and a modified law of the wall to incorporate the reactor wall roughness effects. The performance analysis was carried out using commercial CFD software (ANSYS Fluent 15.0). Four case studies were analyzed based on open channel UV reactor type (horizontal and vertical) and lamp configuration (parallel and staggered). The results show that lamp configuration can play an important role in the performance of an open channel water disinfection UV reactor. The effects of the reactor wall roughness were Reynolds number dependent. The proposed methodology is useful for performance optimization of an open channel water disinfection UV reactor.
5. Weak coupling chambers in N=2 BPS quiver theory
NASA Astrophysics Data System (ADS)
Saidi, El Hassan
2012-11-01
Using recent results on BPS quiver theory, we develop a group theoretical method to describe the quiver mutations encoding the quantum mechanical duality relating the spectra of distinct quivers. We illustrate the method by computing the BPS spectrum of the infinite weak chamber of some examples of N=2 supersymmetric gauge models without and with quark hypermultiplets.
6. A note on multiply wound BPS Wilson loops in ABJM
NASA Astrophysics Data System (ADS)
Bianchi, Marco S.
2016-09-01
We consider BPS Wilson loops in planar ABJM theory, wound multiple times around the great circle. We compute the expectation value of the 1/6-BPS and 1/2-BPS Wilson loops to three- and two-loop order in perturbation theory, respectively, dealing with the combinatorics of multiple winding via recursive relations. For the 1/6-BPS Wilson loop we perform the computation at generic framing and at framing 1 we find agreement with the localization result. For the 1/2-BPS Wilson loop we compute the expectation value at trivial framing and by comparison with the matrix model expression we extract the framing dependence of the fermion diagrams.
7. Spectral characteristics of airway opening and chest wall tidal flows in spontaneously breathing preterm infants.
PubMed
Habib, Robert H; Pyon, Kee H; Courtney, Sherry E; Aghai, Zubair H
2003-05-01
We compared the harmonic content of tidal flows measured simultaneously at the mouth and chest wall in spontaneously breathing very low birth weight infants (n = 16, 1,114 +/- 230 g, gestation age: 28 +/- 2 wk). Airway opening flows were measured via face mask-pneumotachograph (P-tach), whereas chest wall flows were derived from respiratory inductance plethysmography (RIP) excursions. Next, for each, we computed two spectral shape indexes: 1) harmonic distortion (k(d); k(d,P-tach) and k(d,RIP), respectively) defines the extent to which flows deviated from a single sine wave, and 2) the exponent of the power law (s; s(P-tach) and s(RIP), respectively), describing the spectral energy vs. frequency. P-tach and RIP flow spectra exhibited similar power law functional forms consistently in all infants. Also, mouth [s(P-tach) = 3.73 +/- 0.23% (95% confidence interval), k(d,P-tach) = 38.8 +/- 4.6%] and chest wall (s(RIP) = 3.51 +/- 0.30%, k(d,RIP) = 42.8 +/- 4.8%) indexes were similar and highly correlated (s(RIP) = 1.17 x s(P-tach) + 0.85; r(2) = 0.81; k(d,RIP) = 0.90 x k(d,P-tach) + 8.0; r(2) = 0.76). The corresponding time to peak tidal expiratory flow-to-expiratory time ratio (0.62 +/- 0.08) was higher than reported in older infants. The obtained s and k(d) values are similar to those reported in older and/or larger chronic lung disease infants, yet appreciably lower than for 1-mo-old healthy infants of closer age and/or size; this indicated increased complexity of tidal flows in very low birth weight babies. Importantly, we found equivalent flow spectral data from mouth and chest wall tidal flows. The latter are desirable because they avoid face mask artificial effects, including leaks around it, they do not interfere with ventilatory support delivery, and they may facilitate longer measurements that are useful in control of breathing assessment.
8. Microbubbles and blood-brain barrier opening: a numerical study on acoustic emissions and wall stress predictions.
PubMed
Hosseinkhah, Nazanin; Goertz, David E; Hynynen, Kullervo
2015-05-01
Focused ultrasound with microbubbles is an emerging technique for blood-brain barrier opening. Here, a comprehensive theoretical model of a bubble-fluid-vessel system has been developed which accounts for the bubble's nonspherical oscillations inside a microvessel, and its resulting acoustic emissions. Numerical simulations of unbound and confined encapsulated bubbles were performed to evaluate the effect of the vessel wall on acoustic emissions and vessel wall stresses. Using a Marmottant shell model, the normalized second harmonic to fundamental emissions first decreased as a function of pressure (>50 kPa) until reaching a minima ("transition point") at which point they increased. The transition point of unbound compared to confined bubble populations occurred at different pressures and was associated with an accompanying increase in shear and circumferential wall stresses. As the wall stresses depend on the bubble to vessel wall distance, the stresses were evaluated for bubbles with their wall at a constant distance to a flat wall. As a result, the wall stresses were bubble size and frequency dependent and the peak stress values induced by bubbles larger than resonance remained constant versus frequency at a constant mechanical index.
9. Investigation on Twisting and Side Wall Opening Occurring in Curved Hat Channel Products Made of High Strength Steel Sheets
NASA Astrophysics Data System (ADS)
Takamura, Masato; Fukui, Ayako; Yano, Hiroshi; Hama, Takayuki; Sunaga, Hideyuki; Makinouchi, Akitake; Asakawa, Motoo
2011-08-01
High strength steel sheets are becoming increasingly important for the weight reduction of automotive bodies to meet the requirements for reduced environmental impact. However, dimensional defects resulting from springback are serious issues, and effective methods of predicting and reducing such defects are necessary. In this study, we numerically and experimentally analyzed the mechanisms of dimensional inaccuracies caused by springback occurring in curved hat channel deep drawing products. The analysis was based on the static explicit FEM software "TP-STRUCT" (the solver part is known as "STAMP3D"). The results of the experiments and simulations similarly show that the twist angle is positive (right-hand system) when the drawing height is relatively large. We calculated the twist torque around the longitudinal axis using the stress distributions obtained by FE analysis. Through the investigation of twist torque and its transition during the drawing and die removal processes, we found that the negative torque generated by side wall opening occurring in the die removal process is the dominant factor of the positive twist. Knowing such mechanisms of twist in cases with a relatively large drawing height, we attempted to explore methods of reducing side wall opening by giving the side wall a stepped shape with the eventual aim of reducing twist. Consequently, we concluded that the stepped shape on the side wall has marked effects of reducing side wall opening, mainly through the elimination of bending-unbending effects on die shoulders, which was verified by observing the stress distribution obtained by FE analysis.
10. Cosmic microwave anisotropies from BPS semilocal strings
SciTech Connect
Urrestilla, Jon; Bevis, Neil; Hindmarsh, Mark; Kunz, Martin; Liddle, Andrew R E-mail: [email protected] E-mail: [email protected]
2008-07-15
We present the first ever calculation of cosmic microwave background (CMB) anisotropy power spectra from semilocal cosmic strings, obtained via simulations of a classical field theory. Semilocal strings are a type of non-topological defect arising in some models of inflation motivated by fundamental physics, and are thought to relax the constraints on the symmetry breaking scale as compared to models with (topological) cosmic strings. We derive constraints on the model parameters, including the string tension parameter {mu}, from fits to cosmological data, and find that in this regard Bogomol'nyi-Prasad-Sommerfield (BPS) semilocal strings resemble global textures more than topological strings. The observed microwave anisotropy at l=10 is reproduced if G{mu} = 5.3 Multiplication-Sign 10{sup -6} (G is Newton's constant). However as with other defects the spectral shape does not match observations, and in models with inflationary perturbations plus semilocal strings the 95% confidence level upper bound is G{mu}<2.0 Multiplication-Sign 10{sup -6} when CMB, Hubble key project and big bang nucleosynthesis data are used (cf G{mu}<0.9 Multiplication-Sign 10{sup -6} for cosmic strings). We additionally carry out a Bayesian model comparison of several models with and without defects, showing that models with defects are neither conclusively favoured nor disfavoured at present.
11. Laccases Direct Lignification in the Discrete Secondary Cell Wall Domains of Protoxylem1[W][OPEN
PubMed Central
Schuetz, Mathias; Benske, Anika; Smith, Rebecca A.; Watanabe, Yoichiro; Tobimatsu, Yuki; Ralph, John; Demura, Taku; Ellis, Brian; Samuels, A. Lacey
2014-01-01
Plants precisely control lignin deposition in spiral or annular secondary cell wall domains during protoxylem tracheary element (TE) development. Because protoxylem TEs function to transport water within rapidly elongating tissues, it is important that lignin deposition is restricted to the secondary cell walls in order to preserve the plasticity of adjacent primary wall domains. The Arabidopsis (Arabidopsis thaliana) inducible VASCULAR NAC DOMAIN7 (VND7) protoxylem TE differentiation system permits the use of mutant backgrounds, fluorescent protein tagging, and high-resolution live-cell imaging of xylem cells during secondary cell wall development. Enzymes synthesizing monolignols, as well as putative monolignol transporters, showed a uniform distribution during protoxylem TE differentiation. By contrast, the oxidative enzymes LACCASE4 (LAC4) and LAC17 were spatially localized to secondary cell walls throughout protoxylem TE differentiation. These data support the hypothesis that precise delivery of oxidative enzymes determines the pattern of cell wall lignification. This view was supported by lac4lac17 mutant analysis demonstrating that laccases are necessary for protoxylem TE lignification. Overexpression studies showed that laccases are sufficient to catalyze ectopic lignin polymerization in primary cell walls when exogenous monolignols are supplied. Our data support a model of protoxylem TE lignification in which monolignols are highly mobile once exported to the cell wall, and in which precise targeting of laccases to secondary cell wall domains directs lignin deposition. PMID:25157028
12. Modelling of masonry infill walls participation in the seismic behaviour of RC buildings using OpenSees
NASA Astrophysics Data System (ADS)
Furtado, André; Rodrigues, Hugo; Arêde, António
2015-06-01
Recent earthquakes show that masonry infill walls should be taken into account during the design and assessment process of structures, since this type of non-structural elements increase the in-plane stiffness of the structure and consequently the natural period. An overview of the past researches conducted on the modelling of masonry infilled frame issues has been done, with discussion of past analytical investigations and different modelling approaches that many authors have proposed, including micro- and macro-modelling strategies. After this, the present work presents an improved numerical model, based on the Rodrigues et al. (J Earthq Eng 14:390-416, 2010) approach, for simulating the masonry infill walls behaviour in the computer program OpenSees. The main results of the in-plane calibration analyses obtained with one experimental test are presented and discussed. For last, two reinforced concrete regular buildings were studied and subjected to several ground motions, with and without infills' walls.
13. Intravesical liposome drug delivery and IC/BPS.
PubMed
Janicki, Joseph J; Gruber, Michele A; Chancellor, Michael B
2015-10-01
Intravesical therapy has previously shown to be effective in delaying or preventing recurrence of superficial bladder cancer. This local route of drug administration is now demonstrating promise in the treatment of interstitial cystitis/bladder pain syndrome (IC/BPS) with the benefit of minimal systemic side effects. Liposomes (LPs) are lipid vesicles composed of phospholipid bilayers surrounding an aqueous core. They can incorporate drug molecules, both hydrophobic and hydrophilic, and vastly improve cellular uptake of these drug molecules via endocytosis. Intravesical LPs have therapeutic effects on IC/BPS patients, mainly due to their ability to form a protective lipid film on the urothelial surface and repair the damaged urothelium. This review considers the current status of intravesical LPs and LP mediated drug delivery for the treatment of IC/BPS.
14. BPS Wilson loops in Minkowski spacetime and Euclidean space
NASA Astrophysics Data System (ADS)
Ouyang, Hao; Wu, Jun-Bao; Zhang, Jia-ju
2015-12-01
We give evidence that spacelike BPS Wilson loops do not exist in Minkowski spacetime. We show that spacelike Wilson loops in Minkowski spacetime cannot preserve any supersymmetries, in d = 4 N = 4 super Yang-Mills theory, d = 3 N = 2 super Chern-Simons-matter theory, and d = 3 N = 6 Aharony-Bergman-Jafferis-Maldacena theory. We not only show this using infinite straight lines and circles as examples, but also we give proofs for general curves. We attribute this to the conflicts of the reality conditions of the spinors. However, spacelike Wilson loops do exist in Euclidean space. There are both BPS Wilson loops along infinite straight lines and circular BPS Wilson loops. This is because the reality conditions of the spinors are lost after Wick rotation. The result is reasonable in view of the AdS/CFT correspondence.
15. Exact Attractive Non-BPS STU Black Holes
SciTech Connect
Kallosh, Renata; Sivanandam, Navin; Soroush, Masoud; /Stanford U., Phys. Dept. /SLAC
2006-07-18
We develop some properties of the non-BPS attractive STU black hole. Our principle result is the construction of exact solutions for the moduli, the metric and the vectors in terms of appropriate harmonic functions. In addition, we find a spherically-symmetric attractor carrying p{sup 0} (D6 brane) and q{sub a} (D2 brane) charges by solving the non-BPS attractor equation (which we present in a particularly compact form) and by minimizing an effective black hole potential. Finally, we make an argument for the existence of multicenter attractors and conjecture that if such solutions exist they may provide a resolution to the existence of apparently unstable non-BPS ''attractors''.
16. BPS amplitudes, helicity supertraces and membranes in M-theory
NASA Astrophysics Data System (ADS)
Wit, B. d.; Lüst, D.
2000-03-01
We study BPS dominated loop amplitudes in M-theory on T2. For this purpose we generalize the concept of helicity supertraces to nine spacetime dimensions. These traces distinguish between various massive supermultiplets and appear as coefficients in their one-loop contributions to n-graviton scattering amplitudes. This can be used to show that only ultrashort BPS multiplets contribute to the R4 term in the effective action, which was first computed by Green, Gutperle and Vanhove. There are two inequivalent ultrashort BPS multiplets which describe the Kaluza-Klein states and the wrapped membranes that cover the torus a number of times. From the perspective of the type-II strings they correspond to momentum and winding states and D0 or D1 branes.
17. Secretory COPII Protein SEC31B Is Required for Pollen Wall Development1[OPEN
PubMed Central
Zhao, Bingchun; Shi, Haidan; Wang, Wanlei; Liu, Xiaoyu; Gao, Hui; Wang, Xiaoxiao; Zhang, Yinghui; Yang, Meidi; Li, Rui
2016-01-01
The pollen wall protects pollen grains from abiotic and biotic stresses. During pollen wall development, tapetal cells play a vital role by secreting proteins, signals, and pollen wall material to ensure microspore development. But the regulatory mechanism underlying the secretory pathway of the tapetum is largely unknown. Here, we characterize the essential role of the Arabidopsis (Arabidopsis thaliana) COPII protein SECRETORY31B (SEC31B) in pollen wall development and the secretory activity of tapetal cells. The sporophyte-controlled atsec31b mutant exhibits severe pollen and seed abortion. Transmission electron microscopy observation indicates that pollen exine formation in the atsec31b mutant is disrupted significantly. AtSEC31B is a functional COPII protein revealed by endoplasmic reticulum (ER) exit site localization, interaction with AtSEC13A, and retarded ER-Golgi protein trafficking in the atsec31b mutant. A genetic tapetum-specific rescue assay indicates that AtSEC31B functions primarily in the tapetum. Moreover, deletion of AtSEC31B interrupted the formation of the ER-derived tapetosome and altered the location of the ATP-BINDING CASSETTE TRANSPORTER9 protein in the tapetum. Therefore, this work demonstrates that AtSEC31B plays a vital role in pollen wall development by regulating the secretory pathway of the tapetal cells. PMID:27634427
18. Asymptotic dynamics of monopole walls
NASA Astrophysics Data System (ADS)
Cross, R.
2015-08-01
We determine the asymptotic dynamics of the U(N) doubly periodic BPS monopole in Yang-Mills-Higgs theory, called a monopole wall, by exploring its Higgs curve using the Newton polytope and amoeba. In particular, we show that the monopole wall splits into subwalls when any of its moduli become large. The long-distance gauge and Higgs field interactions of these subwalls are Abelian, allowing us to derive an asymptotic metric for the monopole wall moduli space.
19. Refinement and evaluation of crack-opening-area analyses for circumferential through-wall cracks in pipes
SciTech Connect
Rahman, S.; Brust, F.; Ghadiali, N.; Krishnaswamy, P.; Wilkowski, G.; Choi, Y.H. |; Moberg, F.; Brickstad, B. |
1995-04-01
Leak-before-break (LBB) analyses for circumferentially cracked pipes are currently being conducted in the nuclear industry to justify elimination of pipe whip restraints and jet impingement shields which are present because of the expected dynamic effects from pipe rupture. The application of the LBB methodology frequently requires calculation of leak rates. These leak rates depend on the crack-opening area of a through-wall crack in the pipe. In addition to LBB analyses, which assume a hypothetical flaw size, there is also interest in the integrity of actual leaking cracks corresponding to current leakage detection requirements in NRC Regulatory Guide 1.45, or for assessing temporary repair of Class 2 and 3 pipes that have leaks as are being evaluated in ASME Section 11. This study was requested by the NRC to review, evaluate, and refine current analytical models for crack-opening-area analyses of pipes with circumferential through-wall cracks. Twenty-five pipe experiments were analyzed to determine the accuracy of the predictive models. Several practical aspects of crack-opening such as; crack-face pressure, off-center cracks, restraint of pressure-induced bending, cracks in thickness transition regions, weld residual stresses, crack-morphology models, and thermal-hydraulic analysis, were also investigated. 140 refs., 105 figs., 41 tabs.
20. Role of Glycosyltransferases in Pollen Wall Primexine Formation and Exine Patterning1[OPEN
PubMed Central
Li, Wenhua L.; Liu, Yuanyuan
2017-01-01
The pollen cell wall is important for protection of male sperm from physical stresses and consists of an inner gametophyte-derived intine layer and a sporophyte-derived exine layer. The polymeric constituents of the robust exine are termed sporopollenin. The mechanisms by which sporopollenin is anchored onto microspores and polymerized in specific patterns are unknown, but the primexine, a transient cell wall matrix formed on the surface of microspores at the late tetrad stage, is hypothesized to play a key role. Arabidopsis (Arabidopsis thaliana) spongy (spg) and uneven pattern of exine (upex) mutants exhibit defective and irregular exine patterns. SPG2 (synonymous with IRREGULAR XYLEM9-LIKE [IRX9L]) encodes a family GT43 glycosyltransferase involved in xylan backbone biosynthesis, while UPEX1 encodes a family GT31 glycosyltransferase likely involved in galactosylation of arabinogalactan proteins. Imaging of developing irx9l microspores showed that the earliest detectable defect was in primexine formation. Furthermore, wild-type microspores contained primexine-localized epitopes indicative of the presence of xylan, but these were absent in irx9l. These data, together with the spg phenotype of a mutant in IRX14L, which also plays a role in xylan backbone elongation, indicate the presence of xylan in pollen wall primexine, which plays a role in exine patterning on the microspore surface. We observed an aberrant primexine and irregular patterns of incipient sporopollenin deposition in upex1, suggesting that primexine-localized arabinogalactan proteins could play roles in sporopollenin adhesion and patterning early in microspore wall development. Our data provide new insights into the biochemical and functional properties of the primexine component of the microspore cell wall. PMID:27495941
1. Moss Chloroplasts Are Surrounded by a Peptidoglycan Wall Containing D-Amino Acids[OPEN
PubMed Central
Hirano, Takayuki; Tanidokoro, Koji; Shimizu, Yasuhiro; Kawarabayasi, Yutaka; Ohshima, Toshihisa; Sato, Momo; Tadano, Shinji; Ishikawa, Hayato; Takio, Susumu; Takechi, Katsuaki; Takano, Hiroyoshi
2016-01-01
It is believed that the plastids in green plants lost peptidoglycan (i.e., a bacterial cell wall-containing d-amino acids) during their evolution from an endosymbiotic cyanobacterium. Although wall-like structures could not be detected in the plastids of green plants, the moss Physcomitrella patens has the genes required to generate peptidoglycan (Mur genes), and knocking out these genes causes defects in chloroplast division. Here, we generated P. patens knockout lines (∆Pp-ddl) for a homolog of the bacterial peptidoglycan-synthetic gene encoding d-Ala:d-Ala ligase. ∆Pp-ddl had a macrochloroplast phenotype, similar to other Mur knockout lines. The addition of d-Ala-d-Ala (DA-DA) to the medium suppressed the appearance of giant chloroplasts in ∆Pp-ddl, but the addition of l-Ala-l-Ala (LA-LA), DA-LA, LA-DA, or d-Ala did not. Recently, a metabolic method for labeling bacterial peptidoglycan was established using ethynyl-DA-DA (EDA-DA) and click chemistry to attach an azide-modified fluorophore to the ethynyl group. The ∆Pp-ddl line complemented with EDA-DA showed that moss chloroplasts are completely surrounded by peptidoglycan. Our findings strongly suggest that the moss plastids have a peptidoglycan wall containing d-amino acids. By contrast, no plastid phenotypes were observed in the T-DNA tagged ddl mutant lines of Arabidopsis thaliana. PMID:27325639
2. Static and free-vibrational response of semi-circular graphite-epoxy frames with thin-walled open sections
NASA Technical Reports Server (NTRS)
Collins, J. Scott; Johnson, Eric R.
1989-01-01
Experiments were conducted to measure the three-dimensional static and free vibrational response of two graphite-epoxy, thin-walled, open section frames. The frames are semi-circular with a radius of three feet, and one specimen has an I cross section and the other has a channel cross section. The flexibility influence coefficients were measured in static tests for loads applied at midspan with the ends of the specimens clamped. Natural frequencies and modes were determined from vibrational tests for free and clamped end conditions. The experimental data is used to evaluate a new finite element which was developed specifically for the analysis of curved, thin-walled structures. The formulation of the element is based on a Vlasov-type, thin-walled, curved beam theory. The predictions from the finite element program generally correlated well with the experimental data for the symmetric I-specimen. Discrepancies in some of the data were found to be due to flexibility in the clamped end conditions. With respect to the data for the channel specimen, the correlation was less satisfactory. The finite element analysis predicted the out-of-plane response of the channel specimen reasonably well, but large discrepancies occurred between the predicted in-plane response and the experimental data. The analysis predicted a much more compliant in-plane response than was observed in the experiments.
3. Primary Metabolism during Biosynthesis of Secondary Wall Polymers of Protoxylem Vessel Elements1[OPEN
PubMed Central
Morisaki, Keiko; Sawada, Yuji; Sano, Ryosuke; Yamamoto, Atsushi; Kurata, Tetsuya; Suzuki, Shiro; Matsuda, Mami; Hasunuma, Tomohisa; Hirai, Masami Yokota
2016-01-01
Xylem vessels, the water-conducting cells in vascular plants, undergo characteristic secondary wall deposition and programmed cell death. These processes are regulated by the VASCULAR-RELATED NAC-DOMAIN (VND) transcription factors. Here, to identify changes in metabolism that occur during protoxylem vessel element differentiation, we subjected tobacco (Nicotiana tabacum) BY-2 suspension culture cells carrying an inducible VND7 system to liquid chromatography-mass spectrometry-based wide-target metabolome analysis and transcriptome analysis. Time-course data for 128 metabolites showed dynamic changes in metabolites related to amino acid biosynthesis. The concentration of glyceraldehyde 3-phosphate, an important intermediate of the glycolysis pathway, immediately decreased in the initial stages of cell differentiation. As cell differentiation progressed, specific amino acids accumulated, including the shikimate-related amino acids and the translocatable nitrogen-rich amino acid arginine. Transcriptome data indicated that cell differentiation involved the active up-regulation of genes encoding the enzymes catalyzing fructose 6-phosphate biosynthesis from glyceraldehyde 3-phosphate, phosphoenolpyruvate biosynthesis from oxaloacetate, and phenylalanine biosynthesis, which includes shikimate pathway enzymes. Concomitantly, active changes in the amount of fructose 6-phosphate and phosphoenolpyruvate were detected during cell differentiation. Taken together, our results show that protoxylem vessel element differentiation is associated with changes in primary metabolism, which could facilitate the production of polysaccharides and lignin monomers and, thus, promote the formation of the secondary cell wall. Also, these metabolic shifts correlate with the active transcriptional regulation of specific enzyme genes. Therefore, our observations indicate that primary metabolism is actively regulated during protoxylem vessel element differentiation to alter the cell’s metabolic
4. A Distinct Pathway for Polar Exocytosis in Plant Cell Wall Formation1[OPEN
PubMed Central
Wang, Hao; Zhuang, Xiaohong; Wang, Xiangfeng; Law, Angus Ho Yin; Zhao, Teng; Du, Shengwang; Loy, Michael M.T.; Jiang, Liwen
2016-01-01
Post-Golgi protein sorting and trafficking to the plasma membrane (PM) is generally believed to occur via the trans-Golgi network (TGN). In this study using Nicotiana tabacum pectin methylesterase (NtPPME1) as a marker, we have identified a TGN-independent polar exocytosis pathway that mediates cell wall formation during cell expansion and cytokinesis. Confocal immunofluorescence and immunogold electron microscopy studies demonstrated that Golgi-derived secretory vesicles (GDSVs) labeled by NtPPME1-GFP are distinct from those organelles belonging to the conventional post-Golgi exocytosis pathway. In addition, pharmaceutical treatments, superresolution imaging, and dynamic studies suggest that NtPPME1 follows a polar exocytic process from Golgi-GDSV-PM/cell plate (CP), which is distinct from the conventional Golgi-TGN-PM/CP secretion pathway. Further studies show that ROP1 regulates this specific polar exocytic pathway. Taken together, we have demonstrated an alternative TGN-independent Golgi-to-PM polar exocytic route, which mediates secretion of NtPPME1 for cell wall formation during cell expansion and cytokinesis and is ROP1-dependent. PMID:27531442
5. The IUPHAR/BPS Guide to PHARMACOLOGY: an expert-driven knowledgebase of drug targets and their ligands
PubMed Central
Pawson, Adam J.; Sharman, Joanna L.; Benson, Helen E.; Faccenda, Elena; Alexander, Stephen P.H.; Buneman, O. Peter; Davenport, Anthony P.; McGrath, John C.; Peters, John A.; Southan, Christopher; Spedding, Michael; Yu, Wenyuan; Harmar, Anthony J.
2014-01-01
The International Union of Basic and Clinical Pharmacology/British Pharmacological Society (IUPHAR/BPS) Guide to PHARMACOLOGY (http://www.guidetopharmacology.org) is a new open access resource providing pharmacological, chemical, genetic, functional and pathophysiological data on the targets of approved and experimental drugs. Created under the auspices of the IUPHAR and the BPS, the portal provides concise, peer-reviewed overviews of the key properties of a wide range of established and potential drug targets, with in-depth information for a subset of important targets. The resource is the result of curation and integration of data from the IUPHAR Database (IUPHAR-DB) and the published BPS ‘Guide to Receptors and Channels’ (GRAC) compendium. The data are derived from a global network of expert contributors, and the information is extensively linked to relevant databases, including ChEMBL, DrugBank, Ensembl, PubChem, UniProt and PubMed. Each of the ∼6000 small molecule and peptide ligands is annotated with manually curated 2D chemical structures or amino acid sequences, nomenclature and database links. Future expansion of the resource will complete the coverage of all the targets of currently approved drugs and future candidate targets, alongside educational resources to guide scientists and students in pharmacological principles and techniques. PMID:24234439
6. National Outcomes for Open Ventral Hernia Repair Techniques in Complex Abdominal Wall Reconstruction.
PubMed
Ross, Samuel W; Oommen, Bindhu; Huntington, Ciara; Walters, Amanda L; Lincourt, Amy E; Kercher, Kent W; Augenstein, Vedra A; Heniford, B Todd
2015-08-01
Modern adjuncts to complex, open ventral hernia repair often include component separation (CS) and/or panniculectomy (PAN). This study examines nationwide data to determine how these techniques impact postoperative complications. The National Surgical Quality Improvement Program database was queried from 2005 to 2013 for inpatient, elective open ventral hernia repairs (OVHR). Cases were grouped by the need for and type of concomitant advancement flaps: OVHR alone (OVHRA), OVHR with CS, OVHR with panniculectomy (PAN), or both CS and PAN (BOTH). Multivariate regression to control for confounding factors was conducted. There were 58,845 OVHR: 51,494 OVHRA, 5,357 CS, 1,617 PAN, and 377 BOTH. Wound complications (OVHRA 8.2%, CS 12.8%, PAN 14.4%, BOTH 17.5%), general complications (15.2%, 24.9%, 25.2%, 31.6%), and major complications (6.9%, 11.4%, 7.2%, 13.5%) were different between groups (P < 0.0001). There was no difference in mortality. Multivariate regression showed CS had higher odds of wound [odds ratio (OR) 1.7, 95% confidence interval (CI) 1.5-2.0], general (OR 1.5, 95% CI: 1.3-1.8), and major complications (OR 2.1, 95%, CI: 1.8-2.4), and longer length of stay by 2.3 days. PAN had higher odds of wound (OR 1.5, 95%, CI: 1.3-1.8) and general complications (OR 1.7, 95%CI: 1.5-2.0). Both CS and PAN had higher odds of wound (OR 2.2, 95%, CI: 1.5-3.2), general (OR 2.5, 95%, CI: 1.8-3.4), and major complications (OR 2.2, 95%CI: 1.4-3.4), and two days longer length of stay. In conclusion, patients undergoing OVHR that require CS or PAN have a higher independent risk of complications, which increases when the procedures are combined.
7. Reduced Wall Acetylation Proteins Play Vital and Distinct Roles in Cell Wall O-Acetylation in Arabidopsis1[C][W][OPEN
PubMed Central
Manabe, Yuzuki; Verhertbruggen, Yves; Gille, Sascha; Harholt, Jesper; Chong, Sun-Li; Pawar, Prashant Mohan-Anupama; Mellerowicz, Ewa J.; Tenkanen, Maija; Cheng, Kun; Pauly, Markus; Scheller, Henrik Vibe
2013-01-01
The Reduced Wall Acetylation (RWA) proteins are involved in cell wall acetylation in plants. Previously, we described a single mutant, rwa2, which has about 20% lower level of O-acetylation in leaf cell walls and no obvious growth or developmental phenotype. In this study, we generated double, triple, and quadruple loss-of-function mutants of all four members of the RWA family in Arabidopsis (Arabidopsis thaliana). In contrast to rwa2, the triple and quadruple rwa mutants display severe growth phenotypes revealing the importance of wall acetylation for plant growth and development. The quadruple rwa mutant can be completely complemented with the RWA2 protein expressed under 35S promoter, indicating the functional redundancy of the RWA proteins. Nevertheless, the degree of acetylation of xylan, (gluco)mannan, and xyloglucan as well as overall cell wall acetylation is affected differently in different combinations of triple mutants, suggesting their diversity in substrate preference. The overall degree of wall acetylation in the rwa quadruple mutant was reduced by 63% compared with the wild type, and histochemical analysis of the rwa quadruple mutant stem indicates defects in cell differentiation of cell types with secondary cell walls. PMID:24019426
8. Ultrastructure of the Epidermal Cell Wall and Cuticle of Tomato Fruit (Solanum lycopersicum L.) during Development1[OPEN
PubMed Central
Segado, Patricia; Domínguez, Eva
2016-01-01
The epidermis plays a pivotal role in plant development and interaction with the environment. However, it is still poorly understood, especially its outer epidermal wall: a singular wall covered by a cuticle. Changes in the cuticle and cell wall structures are important to fully understand their functions. In this work, an ultrastructure and immunocytochemical approach was taken to identify changes in the cuticle and the main components of the epidermal cell wall during tomato fruit development. A thin and uniform procuticle was already present before fruit set. During cell division, the inner side of the procuticle showed a globular structure with vesicle-like particles in the cell wall close to the cuticle. Transition between cell division and elongation was accompanied by a dramatic increase in cuticle thickness, which represented more than half of the outer epidermal wall, and the lamellate arrangement of the non-cutinized cell wall. Changes in this non-cutinized outer wall during development showed specific features not shared with other cell walls. The coordinated nature of the changes observed in the cuticle and the epidermal cell wall indicate a deep interaction between these two supramolecular structures. Hence, the cuticle should be interpreted within the context of the outer epidermal wall. PMID:26668335
9. Effect of bioactive peptides (BPs) on the development of Pacific white shrimp ( Litopenaeus vannamei Boone, 1931)
NASA Astrophysics Data System (ADS)
Wang, Guangjun; Yu, Ermeng; Li, Zhifei; Yu, Deguang; Wang, Haiying; Gong, Wangbao
2016-06-01
The present study was conducted to evaluate the feasibility of replacing fish meal (FM) with bioactive peptides (BPs) in diet of white shrimp ( Litopenaeus vannamei). The changes in growth performance, body composition, non-specific immunity, and water quality were examined after the shrimp were fed four diets, in which 0% (control), 33.3%, 66.7% and 100% of FM was replaced by BPs, respectively. The groups were designated as Con, 1/3BPs, 2/3BPs, and 3/3BPs. A total of 720 shrimp with an initial body weight of 1.46 ± 0.78 g were fed the experimental diets for 56 days. The results revealed that: 1) the weight gain rate (WGR) in 1/3BPs, 2/3BPs, and 3/3BPs was significantly higher than that in Con ( P < 0.05), while no significant difference was found on survival rate and feed conversion ratio (FCR); 2) the whole-body crude protein (CP) and crude lipids (CL) were significantly different among groups, while there was no significant difference between crude ash and phosphorus contents; 3) the levels of acid phosphatase (ACP), lysozyme (LZM), superoxide dismutase (SOD), phenol oxidase (PO) and bactericidal activity increased significantly with the inclusion of BPs; 4) in terms of water quality, no significant difference was found in pH and dissolved oxygen among diets during the whole experimental period. Moreover, even though nitrite and ammonium levels tended to increase with time, there was no significant difference among groups. The results indicated that BPs is an applicable alternative of protein source, which can substitute FM in the diets of L. vannamei; it is able to effectively promote growth performance and improve immunity. Moreover, BPs in the diets had no negative impact on water quality.
10. Effects of rat sex differences and lighting on locomotor exploration of a circular open field with free-standing central corners and without peripheral walls.
PubMed
Alstott, Jeff; Timberlake, William
2009-01-23
A typical open field consists of a square enclosure, bounded by four straight walls joined by identical corners. For decades behavioral researchers have used the open center and more sheltered perimeter of such fields to examine the effects of drugs, sex differences, and illumination on the behavioral expression of fear and anxiety. The present study "reversed" the relative security of the center and periphery of a circular field to re-examine the functional relation of open field behavior to experience, sex differences and lighting. Across six daily exposures, males in both the light and dark rapidly increased their preference for the center. Females in the light developed a similar pattern, though more slowly; females in the dark continued to spend the great majority of their time in the open periphery, including the edge of the field. The behavior of all groups, but especially the dark females, strongly supports the continued importance of environmental assessment in open field behavior.
11. BPS spectra of N = 2 SO7 and SP4 models
NASA Astrophysics Data System (ADS)
Ahl Laamara, R.; Mellal, O.; Saidi, E. H.
2017-01-01
Extending the folding method of ADE Dynkin diagrams of Lie algebras to BPS quivers of 4d N = 2 supersymmetric gauge theory with ADE type gauge invariance, we study the BPS spectra for gauge symmetries with non-simply laced Lie algebras. Focussing on the 4d N = 2 SO7 and SP4 models, we derive the BPS states of the strong chambers of these theories. We find that for both gauge groups Gnsl = SO7 and SP4 ≃ SO (5) , the number of BPS states of the strongly coupled chamber is 2 dim Gnsl versus 2 dim Gsl - 2 rankGsl for the cousin gauge symmetries Gsl = SO8 and SU4 ≃ SO (6) . The relationship between the Gsl and Gnsl types of BPS quiver mutations is derived. Other features are also studied.
12. Do all BPS black hole microstates carry zero angular momentum?
NASA Astrophysics Data System (ADS)
Chowdhury, Abhishek; Garavuso, Richard S.; Mondal, Swapnamay; Sen, Ashoke
2016-04-01
From the analysis of the near horizon geometry and supersymmetry algebra it has been argued that all the microstates of single centered BPS black holes with four unbroken supersymmetries carry zero angular momentum in the region of the moduli space where the black hole description is valid. A stronger form of the conjecture would be that the result holds for any sufficiently generic point in the moduli space. In this paper we set out to test this conjecture for a class of black hole microstates in type II string theory on T 6, represented by four stacks of D-branes wrapped on various cycles of T 6. For this system the above conjecture translates to the statement that the moduli space of classical vacua must be a collection of points. Explicit analysis of systems carrying a low number of D-branes supports this conjecture.
13. Non-BPS multi-bubble microstate geometries
NASA Astrophysics Data System (ADS)
Bena, Iosif; Bossard, Guillaume; Katmadas, Stefanos; Turton, David
2016-02-01
We construct the first smooth horizonless supergravity solutions that have two topologically-nontrivial three-cycles supported by flux, and that have the same mass and charges as a non-extremal D1-D5-P black hole. Our configurations are solutions to six-dimensional ungauged supergravity coupled to a tensor multiplet, and uplift to solutions of Type IIB supergravity. The solutions represent multi-center generalizations of the non-BPS solutions of Jejjala, Madden, Ross, and Titchener, which have over-rotating angular momenta. By adding an additional Gibbons-Hawking center, we succeed in lowering one of the two angular momenta below the cosmic censorship bound, and bringing the other very close to this bound. Our results demonstrate that it is possible to construct multi-center horizonless solutions corresponding to non-extremal black holes, and offer the prospect of ultimately establishing that finite-temperature black holes have nontrivial structure at the horizon.
14. A 4800 bps CELP vocoder with an improved excitation
NASA Technical Reports Server (NTRS)
Hassanein, Hisham; Brindamour, Andre; Bryden, Karen
1990-01-01
The Stochastic or Code Excited Linear Predictive Coder (CELP) is among the promising candidates for producing good quality speech at low bit rates. However, the speech quality produced suffers from perceived roughness. Many researchers have used pole-zero postfilters to mask the roughness at the output of the synthesis filter. Although the postfilters are effective in masking the noise at low bit rates, they produce spectral distortions. It is proposed that speech can be improved by introducing two modifications to the fixed stochastic codebook. In the first modification, the stochastic codebook is used only when the long term correlations are low. Otherwise, a pulse like codebook is selected. In the second modification, the selected codebook output is weighted using an adaptive spectral shaping procedure. These two modifications were incorporated in a 4800 bps CELP coder and have resulted in a perceptually improved vocoded speech.
15. Topological BPS charges in 10- and 11-dimensional supergravity
NASA Astrophysics Data System (ADS)
Callister, Andrew K.; Smith, Douglas J.
2008-09-01
We consider the supersymmetry algebras of the maximal supergravities in 10 and 11 dimensions. We construct expressions from which the topological charge structure of the algebras can be determined in supersymmetric curved backgrounds. These are interpreted as the topological charges of the 1/2-BPS states that are found in the theories. We consider charges for all the M-, NS- and D-branes as well as the Kaluza-Klein monopoles. We also show that the dimensional reduction relations between the 11-dimensional and IIA charges, and T-duality relations of the IIA and IIB charges, match those found for the branes themselves. Finally we consider the massive versions of the IIA and 11-dimensional theories and find that the expressions for the charges, with a slight modification, are still valid in those instances.
16. Quantum Holonomies from Spectral Networks and Framed BPS States
NASA Astrophysics Data System (ADS)
Gabella, Maxime
2017-04-01
We propose a method for determining the spins of BPS states supported on line defects in 4d N=2 theories of class S. Via the 2d-4d correspondence, this translates to the construction of quantum holonomies on a punctured Riemann surface C. Our approach combines the technology of spectral networks, which decomposes flat {GL(K,C)-connections on C in terms of flat abelian connections on a K-fold cover of C, and the skein algebra in the 3-manifold C × [0,1]}, which expresses the representation theory of the quantum group U q ( gl K ). With any path on C, the quantum holonomy associates a positive Laurent polynomial in the quantized Fock-Goncharov coordinates of higher Teichmüller space. This confirms various positivity conjectures in physics and mathematics.
17. Depletion of cellular iron by bps and ascorbate: effect on toxicity of adriamycin.
PubMed
Nyayapati, S; Afshan, G; Lornitzo, F; Byrnes, R W; Petering, D H
1996-01-01
A new method was developed that reduces the intracellular iron content of cells grown in serum-containing culture without involving the significant uptake of iron-chelating agents into cells. Negatively charged bathophenanthrolinedisulfonate (BPS), together with ascorbate, caused cells to lose much of their cellular iron without causing much depression in HL-60 or H9c2 (2-1) cell proliferation over a 48-h period. When added to serum supplemented RPMI-1640 culture media, BPS and ascorbate efficiently reduced and competed for iron in Fe(III) transferrin to form Fe(II)(BPS)3. The reaction also occurred with purified human iron-transferrin. When cells were incubated with growth medium containing serum that had been treated with BPS and ascorbate for 24 h, little or no BPS2- or Fe(II)(BPS)(4-)3 entered the cells, according to direct measurements and in agreement with the highly unfavorable 1-octanol/water partition coefficients for these molecules. However, iron was mobilized out of both cell types. After 24 h incubation of cells in this medium, there was no change in the activities of catalase and superoxide dismutase, or in the concentration of glutathione. Glutathione peroxidase was elevated 9%. Using HL-60 and H9c2 (2-1) cells made iron deficient with BPS and ascorbate, HL-60 cells grown in defined-growth media in the absence of iron-pyridoxal isonicotinoyl hydrazone, or Euglena gracilis cells maintained in a defined medium that was rigorously depleted of iron, it was shown that the cytotoxicity of adriamycin is markedly dependent on the presence of iron in each type of cell. Similar results were obtained when HL-60 cells were grown in RPMI-1640 culture medium and serum that had been incubated for 24 h in BPS and ascorbate and then chromatographed over a Bio-Rad desalting column to remove small molecules including BPS, ascorbate, and Fe(II)(BPS)3.
18. Synthesis and Enhanced Field-Emission of Thin-Walled, Open-Ended, and Well-Aligned N-Doped Carbon Nanotubes
PubMed Central
2010-01-01
Thin-walled, open-ended, and well-aligned N-doped carbon nanotubes (CNTs) on the quartz slides were synthesized by using acetonitrile as carbon sources. As-obtained products possess large thin-walled index (TWI, defined as the ratio of inner diameter and wall thickness of a CNT). The effect of temperature on the growth of CNTs using acetonitrile as the carbon source was also investigated. It is found that the diameter, the TWI of CNTs increase and the Fe encapsulation in CNTs decreases as the growth temperature rises in the range of 780–860°C. When the growth temperature is kept at 860°C, CNTs with TWI = 6.2 can be obtained. It was found that the filed-emission properties became better as CNT growth temperatures increased from 780 to 860°C. The lowest turn-on and threshold field was 0.27 and 0.49 V/μm, respectively. And the best field-enhancement factors reached 1.09 × 105, which is significantly improved about an order of magnitude compared with previous reports. In this study, about 30 × 50 mm2 free-standing film of thin-walled open-ended well-aligned N-doped carbon nanotubes was also prepared. The free-standing film can be transferred easily to other substrates, which would promote their applications in different fields. PMID:20672122
19. Novel BPS Wilson loops in three-dimensional quiver Chern-Simons-matter theories
NASA Astrophysics Data System (ADS)
Ouyang, Hao; Wu, Jun-Bao; Zhang, Jia-ju
2016-02-01
We show that generic three-dimensional N = 2 quiver super Chern-Simons-matter theories admit Bogomol'nyi-Prasad-Sommerfield (BPS) Drukker-Trancanelli (DT) type Wilson loops. We investigate both Wilson loops along timelike infinite straight lines in Minkowski spacetime and circular Wilson loops in Euclidean space. In Aharnoy-Bergman-Jafferis-Maldacena theory, we find that generic BPS DT type Wilson loops preserve the same number of supersymmetries as Gaiotto-Yin type Wilson loops. There are several free parameters for generic BPS DT type Wilson loops in the construction, and supersymmetry enhancement for Wilson loops happens for special values of the parameters.
20. Pectin Metabolism and Assembly in the Cell Wall of the Charophyte Green Alga Penium margaritaceum1[W][OPEN
PubMed Central
Domozych, David S.; Sørensen, Iben; Popper, Zoë A.; Ochs, Julie; Andreas, Amanda; Fangel, Jonatan U.; Pielach, Anna; Sacks, Carly; Brechka, Hannah; Ruisi-Besares, Pia; Willats, William G.T.; Rose, Jocelyn K.C.
2014-01-01
The pectin polymer homogalacturonan (HG) is a major component of land plant cell walls and is especially abundant in the middle lamella. Current models suggest that HG is deposited into the wall as a highly methylesterified polymer, demethylesterified by pectin methylesterase enzymes and cross-linked by calcium ions to form a gel. However, this idea is based largely on indirect evidence and in vitro studies. We took advantage of the wall architecture of the unicellular alga Penium margaritaceum, which forms an elaborate calcium cross-linked HG-rich lattice on its cell surface, to test this model and other aspects of pectin dynamics. Studies of live cells and microscopic imaging of wall domains confirmed that the degree of methylesterification and sufficient levels of calcium are critical for lattice formation in vivo. Pectinase treatments of live cells and immunological studies suggested the presence of another class of pectin polymer, rhamnogalacturonan I, and indicated its colocalization and structural association with HG. Carbohydrate microarray analysis of the walls of P. margaritaceum, Physcomitrella patens, and Arabidopsis (Arabidopsis thaliana) further suggested the conservation of pectin organization and interpolymer associations in the walls of green plants. The individual constituent HG polymers also have a similar size and branched structure to those of embryophytes. The HG-rich lattice of P. margaritaceum, a member of the charophyte green algae, the immediate ancestors of land plants, was shown to be important for cell adhesion. Therefore, the calcium-HG gel at the cell surface may represent an early evolutionary innovation that paved the way for an adhesive middle lamella in multicellular land plants. PMID:24652345
1. BPS black holes, the Hesse potential, and the topological string
NASA Astrophysics Data System (ADS)
Cardoso, G. L.; de Wit, B.; Mahapatra, S.
2010-06-01
The Hesse potential is constructed for a class of four-dimensional N = 2 supersymmetric effective actions with S- and T-duality by performing the relevant Legendre transform by iteration. It is a function of fields that transform under duality according to an arithmetic subgroup of the classical dualities reflecting the monodromies of the underlying string compactification. These transformations are not subject to corrections, unlike the transformations of the fields that appear in the effective action which are affected by the presence of higher-derivative couplings. The class of actions that are considered includes those of the FHSV and the STU model. We also consider heterotic N = 4 supersymmetric compactifications. The Hesse potential, which is equal to the free energy function for BPS black holes, is manifestly duality invariant. Generically it can be expanded in terms of powers of the modulus that represents the inverse topological string coupling constant, g s , and its complex conjugate. The terms depending holomorphically on g s are expected to correspond to the topological string partition function and this expectation is explicitly verified in two cases. Terms proportional to mixed powers of g s and bar{g}s are in principle present.
2. ABORTED MICROSPORES Acts as a Master Regulator of Pollen Wall Formation in Arabidopsis[C][W][OPEN
PubMed Central
Xu, Jie; Ding, Zhiwen; Vizcay-Barrena, Gema; Shi, Jianxin; Liang, Wanqi; Yuan, Zheng; Werck-Reichhart, Danièle; Schreiber, Lukas; Wilson, Zoe A.; Zhang, Dabing
2014-01-01
Mature pollen is covered by durable cell walls, principally composed of sporopollenin, an evolutionary conserved, highly resilient, but not fully characterized, biopolymer of aliphatic and aromatic components. Here, we report that ABORTED MICROSPORES (AMS) acts as a master regulator coordinating pollen wall development and sporopollenin biosynthesis in Arabidopsis thaliana. Genome-wide coexpression analysis revealed 98 candidate genes with specific expression in the anther and 70 that showed reduced expression in ams. Among these 70 members, we showed that AMS can directly regulate 23 genes implicated in callose dissociation, fatty acids elongation, formation of phenolic compounds, and lipidic transport putatively involved in sporopollenin precursor synthesis. Consistently, ams mutants showed defective microspore release, a lack of sporopollenin deposition, and a dramatic reduction in total phenolic compounds and cutin monomers. The functional importance of the AMS pathway was further demonstrated by the observation of impaired pollen wall architecture in plant lines with reduced expression of several AMS targets: the abundant pollen coat protein extracellular lipases (EXL5 and EXL6), and CYP98A8 and CYP98A9, which are enzymes required for the production of phenolic precursors. These findings demonstrate the central role of AMS in coordinating sporopollenin biosynthesis and the secretion of materials for pollen wall patterning. PMID:24781116
3. Resume and Report of Visitations to Schools Employing the Open-Space Concept of School Construction ("Schools-Without-Walls").
ERIC Educational Resources Information Center
Ramsey, Robert
Four schools were visited in an attempt to assess the merits of combining several classrooms in a large space as a method of school construction. Interviews with students and teachers as well as personal impressions form the basis for evaluation. Satisfactory results were found for schools-without-walls, school carpeting, acoustic control, team…
4. Defective Pollen Wall 2 (DPW2) Encodes an Acyl Transferase Required for Rice Pollen Development1[OPEN
PubMed Central
Shi, Jianxin; Rautengarten, Carsten; Yang, Li; Uzair, Muhammad; Zhu, Lu; Luo, Qian; An, Gynheung; Waßmann, Fritz
2017-01-01
Aliphatic and aromatic lipids are both essential structural components of the plant cuticle, an important interface between the plant and environment. Although cross links between aromatic and aliphatic or other moieties are known to be associated with the formation of leaf cutin and root and seed suberin, the contribution of aromatic lipids to the biosynthesis of anther cuticles and pollen walls remains elusive. In this study, we characterized the rice (Oryza sativa) male sterile mutant, defective pollen wall 2 (dpw2), which showed an abnormal anther cuticle, a defective pollen wall, and complete male sterility. Compared with the wild type, dpw2 anthers have increased amounts of cutin and waxes and decreased levels of lipidic and phenolic compounds. DPW2 encodes a cytoplasmically localized BAHD acyltransferase. In vitro assays demonstrated that recombinant DPW2 specifically transfers hydroxycinnamic acid moieties, using ω-hydroxy fatty acids as acyl acceptors and hydroxycinnamoyl-CoAs as acyl donors. Thus, The cytoplasmic hydroxycinnamoyl-CoA:ω-hydroxy fatty acid transferase DPW2 plays a fundamental role in male reproduction via the biosynthesis of key components of the anther cuticle and pollen wall. PMID:27246096
5. Various computational conditions of oscillatory natural convection of zero Prandtl number fluid in an open boat heated and cooled from opposing vertical walls
SciTech Connect
Okada, Kazuto . Interdisciplinary Graduate School of Engineering Science); Ozoe, Hiroyuki . Inst. of Advanced Material Study)
1993-03-01
The finite-difference computational scheme is developed for two-dimensional oscillatory natural convection of zero Prandtl number fluid in an open boat heated and cooled from opposing vertical walls. Various computational conditions are tested, such as the initial condition, time step length, finite-difference width, and finite-difference scheme. Instantaneous contour maps and velocity vectors in oscillatory states are presented in a series of maps to represent the fluctuating characteristics of two-dimensional roll cells. The physical conditions are for a boat with aspect ratio A = 3[minus]5 at Pr = 0 and Gr = 14,000-40,000.
6. Effect of local estrogen therapy (LET) on urinary and sexual symptoms in premenopausal women with interstitial cystitis/bladder pain syndrome (IC/BPS).
PubMed
Gardella, Barbara; Iacobone, Anna Daniela; Porru, Daniele; Musacchi, Valentina; Dominoni, Mattia; Tinelli, Carmine; Spinillo, Arsenio; Nappi, Rossella E
2015-10-01
The association between vulvodynia and interstitial cystitis/bladder pain syndrome (IC/BPS), a chronic, debilitating disease of unknown etiology, may involve sex hormone-dependent mechanisms regulating vulvo-vaginal health. We aimed to prospectively investigate the effects of 12 weeks of local estrogen therapy (LET) on urinary/bladder and sexual symptoms in premenopausal women with IC/BPS. Thirty-four women (mean age: 36.1 ± 8.4) diagnosed with IC/BPS were treated vulvo-vaginally three-times/week with estriol 0.5 mg cream and tested by validated questionnaires (ICSI/ICPI, pain urgency frequency [PUF], female sexual function index [FSFI]) and by cotton swab testing, vaginal health index (VHI) and maturation index (MI) before and after treatment. Vulvodynia was present in 94.1% of IC/BPS women. A significant positive effect of LET was evident on urinary and sexual function (p < 0.001, for both) following 12 weeks, as well as an improvement of the VHI (p < 0.001) and the MI (p < 0.04). The results of this open study indicate that 12 weeks of local estriol cream at vaginal and vestibular level may ameliorate urinary/bladder pain symptoms, as well as may improve domains of sexual function. The association between vulvar pain and bladder pain could, therefore, be related to a vaginal environment carrying signs of hypoestrogenism, but further studies are needed to clarify this issue.
7. N = 8 BPS black holes preserving 1/8 supersymmetry
NASA Astrophysics Data System (ADS)
Bertolini, M.; Frè, P.; Trigiante, M.
1999-05-01
In the context of N = 8 supergravity we consider BPS black holes that preserve 1/8 supersymmetry. It was shown in a previous paper that, modulo U-duality transformations of E7(7), the most general solution of this type can be reduced to a black hole of the STU model. In this paper we analyse this solution in detail, considering in particular its embedding in one of the possible special Kähler manifolds compatible with the consistent truncations to N = 2 supergravity, this manifold being the moduli space of the T6/icons/Journals/Common/BbbZ" ALT="BbbZ" ALIGN="MIDDLE"/>3 orbifold, that is SU(3,3)/SU(3) × U(3). This construction requires a crucial use of the solvable Lie algebra formalism. Once the group-theoretical analysis is done, starting from a static, spherically symmetric ansatz, we find an exact solution for all the scalars (both dilaton- and axion-like) and for gauge fields, together with their already known charge-dependent fixed values, which yield a U-duality-invariant entropy. We also give a complete translation dictionary between the solvable Lie algebra and the special Kähler formalisms in order to allow a more immediate comparison with other papers on similar issues. Although the explicit solution is given in a simplified case where the equations turn out to be more manageable, it encodes all the features of the more general one, namely it has non-vanishing entropy and the scalar fields have a non-trivial radial dependence.
8. Putrescine Alleviates Iron Deficiency via NO-Dependent Reutilization of Root Cell-Wall Fe in Arabidopsis1[OPEN
PubMed Central
Zhu, Xiao Fang; Wang, Bin; Song, Wen Feng; Zheng, Shao Jian; Shen, Ren Fang
2016-01-01
Plants challenged with abiotic stress show enhanced polyamines levels. Here, we show that the polyamine putrescine (Put) plays an important role to alleviate Fe deficiency. The adc2-1 mutant, which is defective in Put biosynthesis, was hypersensitive to Fe deficiency compared with wild type (Col-1 of Arabidopsis [Arabidopsis thaliana]). Exogenous Put decreased the Fe bound to root cell wall, especially to hemicellulose, and increased root and shoot soluble Fe content, thus alleviating the Fe deficiency-induced chlorosis. Intriguingly, exogenous Put induced the accumulation of nitric oxide (NO) under both Fe-sufficient (+Fe) and Fe-deficient (-Fe) conditions, although the ferric-chelate reductase (FCR) activity and the expression of genes related to Fe uptake were induced only under -Fe treatment. The alleviation of Fe deficiency by Put was diminished in the hemicellulose-level decreased mutant-xth31 and in the noa1 and nia1nia2 mutants, in which the endogenous NO levels are reduced, indicating that both NO and hemicellulose are involved in Put-mediated alleviation of Fe deficiency. However, the FCR activity and the expression of genes related to Fe uptake were still up-regulated under -Fe+Put treatment compared with -Fe treatment in xth31, and Put-induced cell wall Fe remobilization was abolished in noa1 and nia1nia2, indicating that Put-regulated cell wall Fe reutilization is dependent on NO. From our results, we conclude that Put is involved in the remobilization of Fe from root cell wall hemicellulose in a process dependent on NO accumulation under Fe-deficient condition in Arabidopsis. PMID:26578707
9. Wall crossing, quivers and crystals
NASA Astrophysics Data System (ADS)
Aganagic, Mina; Schaeffer, Kevin
2012-10-01
We study the spectrum of BPS D-branes on a Calabi-Yau manifold using the 0 + 1 dimensional quiver gauge theory that describes the dynamics of the branes at low energies. We argue that Seiberg dualities of the quiver correspond to crossing the "walls of the second kind" of Kontsevich and Soibelman. There is a large class of examples where the BPS degeneracies of quivers corresponding to one D6 brane bound to arbitrary numbers of D4, D2 and D0 branes are counted by melting crystal configurations. The shape of the crystal is determined by the Calabi-Yau geometry and the background B-field, and its microscopic structure by the quiver Q. We prove that the BPS degeneracies computed from Q and Q' are related by the Kontsevich-Soibelman formula. We also show that, in the limit of infinite B-field, the combinatorics of crystals becomes that of the topological vertex, thus re-deriving the Gromov-Witten/Donaldson-Thomas correspondence.
10. Evolution and functional diversity of the Calcium Binding Proteins (CaBPs)
PubMed Central
Haynes, Lee P.; McCue, Hannah V.; Burgoyne, Robert D.
2012-01-01
The mammalian central nervous system (CNS) exhibits a remarkable ability to process, store, and transfer information. Key to these activities is the use of highly regulated and unique patterns of calcium signals encoded by calcium channels and decoded by families of specific calcium-sensing proteins. The largest family of eukaryotic calcium sensors is those related to the small EF-hand containing protein calmodulin (CaM). In order to maximize the usefulness of calcium as a signaling species and to permit the evolution and fine tuning of the mammalian CNS, families of related proteins have arisen that exhibit characteristic calcium binding properties and tissue-, cellular-, and sub-cellular distribution profiles. The Calcium Binding Proteins (CaBPs) represent one such family of vertebrate specific CaM like proteins that have emerged in recent years as important regulators of essential neuronal target proteins. Bioinformatic analyses indicate that the CaBPs consist of two subfamilies and that the ancestral members of these are CaBP1 and CaBP8. The CaBPs have distinct intracellular localizations based on different targeting mechanisms including a novel type-II transmembrane domain in CaBPs 7 and 8 (otherwise known as calneuron II and calneuron I, respectively). Recent work has led to the identification of new target interactions and possible functions for the CaBPs suggesting that they have multiple physiological roles with relevance for the normal functioning of the CNS. PMID:22375103
11. Higher dimensional curved domain walls on Kähler surfaces
NASA Astrophysics Data System (ADS)
Akbar, Fiki T.; Gunara, Bobby E.; Radjabaycolle, Flinn C.; Wijaya, Rio N.
2017-03-01
In this paper we study some aspects of curved BPS-like domain walls in higher dimensional gravity theory coupled to scalars where the scalars span a complex Kähler surface with scalar potential turned on. Assuming that a fake superpotential has a special form which depends on Kähler potential and a holomorphic function, we prove that BPS-like equations have a local unique solution. Then, we analyze the vacuum structure of the theory including their stability using dynamical system and their existence in ultraviolet-infrared regions using renormalization group flow.
12. Protected couplings and BPS dyons in half-maximal supersymmetric string vacua
NASA Astrophysics Data System (ADS)
Bossard, Guillaume; Cosnier-Horeau, Charles; Pioline, Boris
2017-02-01
We analyze four- and six-derivative couplings in the low energy effective action of D = 3 string vacua with half-maximal supersymmetry. In analogy with an earlier proposal for the (∇Φ) 4 coupling, we propose that the ∇2(∇Φ) 4 coupling is given exactly by a manifestly U-duality invariant genus-two modular integral. In the limit where a circle in the internal torus decompactifies, the ∇2(∇Φ) 4 coupling reduces to the ∇2F4 and R2F2 couplings in D = 4, along with an infinite series of corrections of order e-R, from four-dimensional 1/4-BPS dyons whose worldline winds around the circle. Each of these contributions is weighted by a Fourier coefficient of a meromorphic Siegel modular form, explaining and extending standard results for the BPS index of 1/4-BPS dyons.
13. Exactly stable non-BPS spinors in heterotic string theory on tori
NASA Astrophysics Data System (ADS)
Seo, Jihye
2013-01-01
Considering SO(32) heterotic string theory compactified on T d with d ≤ 4, stability of non-supersymmetric states is studied. A non-supersymmetric state with robust stability is constructed, and its exact stability is proven in a large region of moduli space against all the possible decay mechanisms allowed by charge conservation. Using various T -duality transform matrices of [1], we translate various selection rules about conserved charges into simpler problems resembling partition and parity of integers. For heterotic string on T 4, we give a complete list of BPS atoms with elementary excitations, and we study BPS and non-BPS molecules with various binding energies. Using string-string duality, the results are interpreted in terms of Dirichlet-branes in type IIA string theory compactified on an orbifold limit of a K3 surface.
14. Non-BPS D-brane solutions in six dimensional orbifolds
NASA Astrophysics Data System (ADS)
Lozano, Y.
2000-08-01
Starting with the non-BPS D0-brane solution of IIB/(-1)FLI4 constructed recently by Eyras and Panda we construct via T-duality the non-BPS D2-brane and D1-brane solutions of IIB/(-1)FLI4 and IIA/(-1)FLI4 predicted by Sen. The D2-brane couples magnetically to the vector field of the NS5B-brane living in the twisted sector of the Type IIB orbifold, whereas the D1-brane couples (electrically and magnetically) to the self-dual 2-form potential of the NS5A-brane that is present in the twisted sector of the Type IIA orbifold construction. Finally we discuss the eleven dimensional interpretation of these branes as originating from a non-BPS M1-brane solution of M-theory orientifolded by ΩρI5.
15. Transparent and Self-Supporting Graphene Films with Wrinkled- Graphene-Wall-Assembled Opening Polyhedron Building Blocks for High Performance Flexible/Transparent Supercapacitors.
PubMed
Li, Na; Huang, Xuankai; Zhang, Haiyan; Li, Yunyong; Wang, Chengxin
2017-03-22
Improving mass loading while maintaining high transparency and large surface area in one self-supporting graphene film is still a challenge. Unfortunately, all of these factors are absolutely essential for enhancing the energy storage performance of transparent supercapacitors for practical applications. To solve the above bottleneck problem, we produce a novel self-supporting flexible and transparent graphene film (STF-GF) with wrinkled-wall-assembled opened-hollow polyhedron building units. Taking advantage of the microscopic morphology, the STF-GF exhibits improved mass loading with high transmittance (70.2% at 550 nm), a large surface area (1105.6 m(2)/g), and good electrochemical performance: high energy (552.3 μWh/cm(3)), power densities (561.9 mW/cm(3)), a superlong cycle life, and good cycling stability (the capacitance retention is ∼94.8% after 20,000 cycles).
16. Measurement of gas species, temperatures, coal burnout, and wall heat fluxes in a 200 MWe lignite-fired boiler with different overfire air damper openings
SciTech Connect
Jianping Jing; Zhengqi Li; Guangkui Liu; Zhichao Chen; Chunlong Liu
2009-07-15
Measurements were performed on a 200 MWe, wall-fired, lignite utility boiler. For different overfire air (OFA) damper openings, the gas temperature, gas species concentration, coal burnout, release rates of components (C, H, and N), furnace temperature, and heat flux and boiler efficiency were measured. Cold air experiments for a single burner were conducted in the laboratory. The double-swirl flow pulverized-coal burner has two ring recirculation zones starting in the secondary air region in the burner. As the secondary air flow increases, the axial velocity of air flow increases, the maxima of radial velocity, tangential velocity and turbulence intensity all increase, and the swirl intensity of air flow and the size of recirculation zones increase slightly. In the central region of the burner, as the OFA damper opening widens, the gas temperature and CO concentration increase, while the O{sub 2} concentration, NOx concentration, coal burnout, and release rates of components (C, H, and N) decrease, and coal particles ignite earlier. In the secondary air region of the burner, the O{sub 2} concentration, NOx concentration, coal burnout, and release rates of components (C, H, and N) decrease, and the gas temperature and CO concentration vary slightly. In the sidewall region, the gas temperature, O{sub 2} concentration, and NOx concentration decrease, while the CO concentration increases and the gas temperature varies slightly. The furnace temperature and heat flux in the main burning region decrease appreciably, but increase slightly in the burnout region. The NOx emission decreases from 1203.6 mg/m{sup 3} (6% O{sub 2}) for a damper opening of 0% to 511.7 mg/m{sup 3} (6% O{sub 2}) for a damper opening of 80% and the boiler efficiency decreases from 92.59 to 91.9%. 15 refs., 17 figs., 3 tabs.
17. Wall modified photonic crystal fibre capillaries as porous layer open tubular columns for in-capillary micro-extraction and capillary chromatography.
PubMed
Kazarian, Artaches A; Sanz Rodriguez, Estrella; Deverell, Jeremy A; McCord, James; Muddiman, David C; Paull, Brett
2016-01-28
Wall modified photonic crystal fibre capillary columns for in-capillary micro-extraction and liquid chromatographic separations is presented. Columns contained 126 internal parallel 4 μm channels, each containing a wall bonded porous monolithic type polystyrene-divinylbenzene layer in open tubular column format (PLOT). Modification longitudinal homogeneity was monitored using scanning contactless conductivity detection and scanning electron microscopy. The multichannel open tubular capillary column showed channel diameter and polymer layer consistency of 4.2 ± 0.1 μm and 0.26 ± 0.02 μm respectively, and modification of 100% of the parallel channels with the monolithic polymer. The modified multi-channel capillaries were applied to the in-capillary micro-extraction of water samples. 500 μL of water samples containing single μg L(-1) levels of polyaromatic hydrocarbons were extracted at a flow rate of 10 μL min(-1), and eluted in 50 μL of acetonitrile for analysis using HPLC with fluorescence detection. HPLC LODs were 0.08, 0.02 and 0.05 μg L(-1) for acenaphthene, anthracene and pyrene, respectively, with extraction recoveries of between 77 and 103%. The modified capillaries were also investigated briefly for direct application to liquid chromatographic separations, with the retention and elution of a standard protein (cytochrome c) under isocratic conditions demonstrated, proving chromatographic potential of the new column format, with run-to-run retention time reproducibility of below 1%.
18. Rotational-vibrational coupling in the BPS Skyrme model of baryons
NASA Astrophysics Data System (ADS)
Adam, C.; Naya, C.; Sanchez-Guillen, J.; Wereszczynski, A.
2013-11-01
We calculate the rotational-vibrational spectrum in the BPS Skyrme model for the hedgehog skyrmion with baryon number one. The resulting excitation energies for the nucleon and delta Roper resonances are slightly above their experimental values. Together with the fact that in the standard Skyrme model these excitation energies are significantly lower than the experimental ones, this provides strong evidence for the conjecture that the inclusion of the BPS Skyrme model is required for a successful quantitative description of physical properties of baryons and nuclei.
19. Radiation damping of a BPS monopole: An illustration of S duality
NASA Astrophysics Data System (ADS)
Bak, Dongsu; Min, Hyunsoo
1997-11-01
The radiation reaction of a BPS monopole in the presence of incident electromagnetic waves as well as massless Higgs waves is analyzed classically. The reactive force and higher-order (finite size) effect are compared to those of the W boson that is interpreted as a dual partner of the BPS monopole. It is shown that the damping of acceleration is dual to each other, while in the case of the finite size effect the duality is broken explicitly. Their implications on the duality are discussed.
20. Cell Wall Invertase Promotes Fruit Set under Heat Stress by Suppressing ROS-Independent Cell Death1[OPEN
PubMed Central
2016-01-01
Reduced cell wall invertase (CWIN) activity has been shown to be associated with poor seed and fruit set under abiotic stress. Here, we examined whether genetically increasing native CWIN activity would sustain fruit set under long-term moderate heat stress (LMHS), an important factor limiting crop production, by using transgenic tomato (Solanum lycopersicum) with its CWIN inhibitor gene silenced and focusing on ovaries and fruits at 2 d before and after pollination, respectively. We found that the increase of CWIN activity suppressed LMHS-induced programmed cell death in fruits. Surprisingly, measurement of the contents of H2O2 and malondialdehyde and the activities of a cohort of antioxidant enzymes revealed that the CWIN-mediated inhibition on programmed cell death is exerted in a reactive oxygen species-independent manner. Elevation of CWIN activity sustained Suc import into fruits and increased activities of hexokinase and fructokinase in the ovaries in response to LMHS. Compared to the wild type, the CWIN-elevated transgenic plants exhibited higher transcript levels of heat shock protein genes Hsp90 and Hsp100 in ovaries and HspII17.6 in fruits under LMHS, which corresponded to a lower transcript level of a negative auxin responsive factor IAA9 but a higher expression of the auxin biosynthesis gene ToFZY6 in fruits at 2 d after pollination. Collectively, the data indicate that CWIN enhances fruit set under LMHS through suppression of programmed cell death in a reactive oxygen species-independent manner that could involve enhanced Suc import and catabolism, HSP expression, and auxin response and biosynthesis. PMID:27462084
1. Beginning Postsecondary Students Longitudinal Study First Follow-up (BPS:96/98) Field Test Report. Working Paper Series.
ERIC Educational Resources Information Center
Pratt, Daniel J.; Wine, Jennifer S.; Heuer, Ruth E.; Whitmore, Roy W.; Kelly, Janice E.; Doherty, John M.; Simpson, Joe B.; Marti, Norma
This report describes the methods and procedures used for the field test of the Beginning Postsecondary Students Longitudinal Study First Followup 1996-98 (BPS:96/98). Students in this survey were first interviewed during 1995 as part of the National Postsecondary Student Aid Study 1996 field test. The BPS:96/98 full-scale student sample includes…
2. Bilingual Pupil Services (B.P.S.) 1988-89. OREA Evaluation Section Report.
ERIC Educational Resources Information Center
Berney, Tomi D.; Barrera, Marbella
The Bilingual Pupil Services (BPS) had two complementary objectives: (1) to provide supplementary services to students of limited English proficiency (LEP) by giving them instruction in English as a Second Language (ESL) and bilingual reading and mathematics; and (2) to provide in-service training to paraprofessionals who were enrolled in programs…
3. Construction and classification of novel BPS Wilson loops in quiver Chern-Simons-matter theories
NASA Astrophysics Data System (ADS)
Ouyang, Hao; Wu, Jun-Bao; Zhang, Jia-ju
2016-09-01
In this paper we construct and classify novel Drukker-Trancanelli (DT) type BPS Wilson loops along infinite straight lines and circles in N = 2 , 3 quiver superconformal Chern-Simons-matter theories, Aharony-Bergman-Jafferis-Maldacena (ABJM) theory, and N = 4 orbifold ABJM theory. Generally we have four classes of Wilson loops, and all of them preserve the same supersymmetries as the BPS Gaiotto-Yin (GY) type Wilson loops. There are several free complex parameters in the DT type BPS Wilson loops, and for two classes of Wilson loops in ABJM theory and N = 4 orbifold ABJM theory there are supersymmetry enhancements at special values of the parameters. We check that the differences of the DT type and GY type Wilson loops are Q-exact with Q being some supercharges preserved by both the DT type and GY type Wilson loops. The results would be useful to calculate vacuum expectation values of the DT type Wilson loops in matrix models if they are still BPS quantum mechanically.
4. Beginning Postsecondary Students Longitudinal Study Second Follow-up (BPS:90/94) Final Technical Report.
ERIC Educational Resources Information Center
Pratt, Daniel J.; And Others
This document provides a summary and evaluation of the methodological procedures and results of the full-scale implementation of the Beginning Postsecondary Student Longitudinal Study Second Follow-up, 1990-94 (BPS:90/94). The study was conducted for the National Center for Education Statistics by Research Triangle Institute with the assistance of…
5. Beginning Postsecondary Students Longitudinal Study: 1996-2001 (BPS: 1996/2001) Methodology Report. Technical Report.
ERIC Educational Resources Information Center
Wine, Jennifer S.; Heuer, Ruth E.; Wheeless, Sara C.; Francis, Talbric L.; Franklin, Jeff W.; Dudley, Kristin M.
This report describes the methods and procedures used for the full-scale data collection effort of the Beginning Postsecondary Students Second Follow-up Student 1996-2001 (BPS:1996/2001). These students, who started their postsecondary education in the 1995-1996 academic year, were first interviewed during 1996, and subsequently interviewed in…
6. Air Force Armament Laboratory (AFATL) battery power supply (BPS) operations and maintenance
NASA Astrophysics Data System (ADS)
Delaney, J. R.; Lippert, J. R.; Herald, W. L.
1991-01-01
The successful operation of the AFATL BPS system is discussed in terms of its proven reliable performance record, flexibility to adapt to different test configurations, and relatively inexpensive operating maintenance costs per test. The BPS consists of 13,728 batteries, interconnecting buswork, and a power conditioning inductor. The system is subdivided into six modules, each divided into six gangs with its own gang switch, each gang containing 24 battery strings. Each module has its own main bus pair, with the negative bus common and the positive bus switched. The operational and performance history of the AFATL BPS has proven that this battery system is effective as a prime power supply for hypervelocity launcher research. Turn-around time between tests has generally been less than that required for the test article. The power capabilities of the BPS can easily be expanded to the design point of a 200 MJ energy store. This can be done by adding more modules of batteries and reconfiguring the inductor with its existing three auxiliary turns in series.
7. 1/4-BPS M-theory bubbles with SO(3) × SO(4) symmetry
NASA Astrophysics Data System (ADS)
Kim, Hyojoong; Kiu Kim, Kyung; Kim, Nakwoo
2007-08-01
In this paper we generalize the work of Lin, Lunin and Maldacena on the classification of 1/2-BPS M-theory solutions to a specific class of 1/4-BPS configurations. We are interested in the solutions of 11 dimensional supergravity with SO(3) × SO(4) symmetry, and it is shown that such solutions are constructed over a one-parameter familiy of 4 dimensional almost Calabi-Yau spaces. Through analytic continuations we can obtain M-theory solutions having AdS2 × S3 or AdS3 × S2 factors. It is shown that our result is equivalent to the AdS solutions which have been recently reported as the near-horizon geometry of M2 or M5-branes wrapped on 2 or 4-cycles in Calabi-Yau threefolds. We also discuss the hierarchy of M-theory bubbles with different number of supersymmetries.
8. Non-BPS attractors in 5 d and 6 d extended supergravity
NASA Astrophysics Data System (ADS)
Andrianopoli, L.; Ferrara, S.; Marrani, A.; Trigiante, M.
2008-05-01
We connect the attractor equations of a certain class of N=2, d=5 supergravities with their (1,0), d=6 counterparts, by relating the moduli space of non-BPS d=5 black hole/black string attractors to the moduli space of extremal dyonic black string d=6 non-BPS attractors. For d=5 real special symmetric spaces and for N=4,6,8 theories, we explicitly compute the flat directions of the black object potential corresponding to vanishing eigenvalues of its Hessian matrix. In the case N=4, we study the relation to the (2,0), d=6 theory. We finally describe the embedding of the N=2, d=5 magic models in N=8, d=5 supergravity as well as the interconnection among the corresponding charge orbits.
9. Description of 1/4 BPS configurations in minimal type IIB supergravity
SciTech Connect
Donos, Aristomenis
2007-01-15
In this paper we present an effort to extend the LLM construction of 1/2 BPS states in minimal IIB supergravity to configurations that preserve 1/4 of the total number of supersymmetries. Following the same techniques we reduce the problem to that of a single scalar which satisfies a nonlinear equation. In particular, the scalar is identified to be the Kahler potential with which a four dimensional base space is equipped.
10. Description of 1/4 BPS configurations in minimal typeIIB supergravity
NASA Astrophysics Data System (ADS)
Donos, Aristomenis
2007-01-01
In this paper we present an effort to extend the LLM construction of 1/2 BPS states in minimal IIB supergravity to configurations that preserve 1/4 of the total number of supersymmetries. Following the same techniques we reduce the problem to that of a single scalar which satisfies a nonlinear equation. In particular, the scalar is identified to be the Kahler potential with which a four dimensional base space is equipped.
11. The Protein BpsB Is a Poly-β-1,6-N-acetyl-d-glucosamine Deacetylase Required for Biofilm Formation in Bordetella bronchiseptica*
PubMed Central
Little, Dustin J.; Milek, Sonja; Bamford, Natalie C.; Ganguly, Tridib; DiFrancesco, Benjamin R.; Nitz, Mark; Deora, Rajendar; Howell, P. Lynne
2015-01-01
Bordetella pertussis and Bordetella bronchiseptica are the causative agents of whooping cough in humans and a variety of respiratory diseases in animals, respectively. Bordetella species produce an exopolysaccharide, known as the Bordetella polysaccharide (Bps), which is encoded by the bpsABCD operon. Bps is required for Bordetella biofilm formation, colonization of the respiratory tract, and confers protection from complement-mediated killing. In this report, we have investigated the role of BpsB in the biosynthesis of Bps and biofilm formation by B. bronchiseptica. BpsB is a two-domain protein that localizes to the periplasm and outer membrane. BpsB displays metal- and length-dependent deacetylation on poly-β-1,6-N-acetyl-d-glucosamine (PNAG) oligomers, supporting previous immunogenic data that suggests Bps is a PNAG polymer. BpsB can use a variety of divalent metal cations for deacetylase activity and showed highest activity in the presence of Ni2+ and Co2+. The structure of the BpsB deacetylase domain is similar to the PNAG deacetylases PgaB and IcaB and contains the same circularly permuted family four carbohydrate esterase motifs. Unlike PgaB from Escherichia coli, BpsB is not required for polymer export and has unique structural differences that allow the N-terminal deacetylase domain to be active when purified in isolation from the C-terminal domain. Our enzymatic characterizations highlight the importance of conserved active site residues in PNAG deacetylation and demonstrate that the C-terminal domain is required for maximal deacetylation of longer PNAG oligomers. Furthermore, we show that BpsB is critical for the formation and complex architecture of B. bronchiseptica biofilms. PMID:26203190
12. The protein BpsB is a poly-β-1,6-N-acetyl-D-glucosamine deacetylase required for biofilm formation in Bordetella bronchiseptica.
PubMed
Little, Dustin J; Milek, Sonja; Bamford, Natalie C; Ganguly, Tridib; DiFrancesco, Benjamin R; Nitz, Mark; Deora, Rajendar; Howell, P Lynne
2015-09-11
Bordetella pertussis and Bordetella bronchiseptica are the causative agents of whooping cough in humans and a variety of respiratory diseases in animals, respectively. Bordetella species produce an exopolysaccharide, known as the Bordetella polysaccharide (Bps), which is encoded by the bpsABCD operon. Bps is required for Bordetella biofilm formation, colonization of the respiratory tract, and confers protection from complement-mediated killing. In this report, we have investigated the role of BpsB in the biosynthesis of Bps and biofilm formation by B. bronchiseptica. BpsB is a two-domain protein that localizes to the periplasm and outer membrane. BpsB displays metal- and length-dependent deacetylation on poly-β-1,6-N-acetyl-d-glucosamine (PNAG) oligomers, supporting previous immunogenic data that suggests Bps is a PNAG polymer. BpsB can use a variety of divalent metal cations for deacetylase activity and showed highest activity in the presence of Ni(2+) and Co(2+). The structure of the BpsB deacetylase domain is similar to the PNAG deacetylases PgaB and IcaB and contains the same circularly permuted family four carbohydrate esterase motifs. Unlike PgaB from Escherichia coli, BpsB is not required for polymer export and has unique structural differences that allow the N-terminal deacetylase domain to be active when purified in isolation from the C-terminal domain. Our enzymatic characterizations highlight the importance of conserved active site residues in PNAG deacetylation and demonstrate that the C-terminal domain is required for maximal deacetylation of longer PNAG oligomers. Furthermore, we show that BpsB is critical for the formation and complex architecture of B. bronchiseptica biofilms.
13. Exploring the relation between 4D and 5D BPS solutions
NASA Astrophysics Data System (ADS)
Behrndt, Klaus; Lopes Cardoso, Gabriel; Mahapatra, Swapna
2006-01-01
Based on recent proposals linking four and five-dimensional BPS solutions, we discuss the explicit dictionary between general stationary 4D and 5D supersymmetric solutions in N=2 supergravity theories with cubic prepotentials. All these solutions are completely determined in terms of the same set of harmonic functions and the same set of attractor equations. As an example, we discuss black holes and black rings in Gödel-Taub-NUT spacetime. Then we consider corrections to the 4D solutions associated with more general prepotentials and comment on analogous corrections on the 5D side.
14. Diagonal form factors and hexagon form factors II. Non-BPS light operator
NASA Astrophysics Data System (ADS)
Jiang, Yunfeng
2017-01-01
We study the asymptotic volume dependence of the heavy-heavy-light three-point functions in the N=4 Super-Yang-Mills theory using the hexagon bootstrap approach, where the volume is the length of the heavy operator. We extend the analysis of our previous short letter [1] to the general case where the heavy operators can be in any rank one sector and the light operator being a generic non-BPS operator. We prove the conjecture of Bajnok, Janik and Wereszczynski [2] up to leading finite size corrections.
15. Higher derivative corrections to BPS black hole attractors in 4d gauged supergravity
NASA Astrophysics Data System (ADS)
Hristov, Kiril; Katmadas, Stefanos; Lodato, Ivano
2016-05-01
We analyze BPS black hole attractors in 4d gauged supergravity in the presence of higher derivative supersymmetric terms, including a Weyl-squared-type action, and determine the resulting corrections to the Bekenstein-Hawking entropy. The near-horizon geometry AdS2×S2 (or other Riemann surface) preserves half of the supercharges in N = 2 supergravity with Fayet-Iliopoulos gauging. We derive a relation between the entropy and the black hole charges that suggests via AdS/CFT how subleading corrections contribute to the supersymmetric index in the dual microscopic picture.
16. Accumulation of N-Acetylglucosamine Oligomers in the Plant Cell Wall Affects Plant Architecture in a Dose-Dependent and Conditional Manner1[W][OPEN
PubMed Central
Vanholme, Bartel; Vanholme, Ruben; Turumtay, Halbay; Goeminne, Geert; Cesarino, Igor; Goubet, Florence; Morreel, Kris; Rencoret, Jorge; Bulone, Vincent; Hooijmaijers, Cortwa; De Rycke, Riet; Gheysen, Godelieve; Ralph, John; De Block, Marc; Meulewaeter, Frank; Boerjan, Wout
2014-01-01
To study the effect of short N-acetylglucosamine (GlcNAc) oligosaccharides on the physiology of plants, N-ACETYLGLUCOSAMINYLTRANSFERASE (NodC) of Azorhizobium caulinodans was expressed in Arabidopsis (Arabidopsis thaliana). The corresponding enzyme catalyzes the polymerization of GlcNAc and, accordingly, β-1,4-GlcNAc oligomers accumulated in the plant. A phenotype characterized by difficulties in developing an inflorescence stem was visible when plants were grown for several weeks under short-day conditions before transfer to long-day conditions. In addition, a positive correlation between the oligomer concentration and the penetrance of the phenotype was demonstrated. Although NodC overexpression lines produced less cell wall compared with wild-type plants under nonpermissive conditions, no indications were found for changes in the amount of the major cell wall polymers. The effect on the cell wall was reflected at the transcriptome level. In addition to genes encoding cell wall-modifying enzymes, a whole set of genes encoding membrane-coupled receptor-like kinases were differentially expressed upon GlcNAc accumulation, many of which encoded proteins with an extracellular Domain of Unknown Function26. Although stress-related genes were also differentially expressed, the observed response differed from that of a classical chitin response. This is in line with the fact that the produced chitin oligomers were too small to activate the chitin receptor-mediated signal cascade. Based on our observations, we propose a model in which the oligosaccharides modify the architecture of the cell wall by acting as competitors in carbohydrate-carbohydrate or carbohydrate-protein interactions, thereby affecting noncovalent interactions in the cell wall or at the interface between the cell wall and the plasma membrane. PMID:24664205
17. Differential Effects of Nitrogen Forms on Cell Wall Phosphorus Remobilization Are Mediated by Nitric Oxide, Pectin Content, and Phosphate Transporter Expression1[OPEN
PubMed Central
Zhu, Chun Quan; Zhu, Xiao Fang; Hu, An Yong; Wang, Chao; Dong, Xiao Ying; Shen, Ren-Fang
2016-01-01
NH4+ is a major source of inorganic nitrogen for rice (Oryza sativa), and NH4+ is known to stimulate the uptake of phosphorus (P). However, it is unclear whether NH4+ can also stimulate P remobilization when rice is grown under P-deficient conditions. In this study, we use the two rice cultivars ‘Nipponbare’ and ‘Kasalath’ that differ in their cell wall P reutilization, to demonstrate that NH4+ positively regulates the pectin content and activity of pectin methylesterase in root cell walls under −P conditions, thereby remobilizing more P from the cell wall and increasing soluble P in roots and shoots. Interestingly, our results show that more NO (nitric oxide) was produced in the rice root when NH4+ was applied as the sole nitrogen source compared with the NO3−. The effect of NO on the reutilization of P from the cell walls was further demonstrated through the application of the NO donor SNP (sodium nitroprusside) and c-PTIO (NO scavenger 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide). What’s more, the P-transporter gene OsPT2 is up-regulated under NH4+ supplementation and is therefore involved in the stimulated P remobilization. In conclusion, our data provide novel (to our knowledge) insight into the regulatory mechanism by which NH4+ stimulates Pi reutilization in cell walls of rice. PMID:27208223
18. The Arabidopsis Class III Peroxidase AtPRX71 Negatively Regulates Growth under Physiological Conditions and in Response to Cell Wall Damage1[OPEN
PubMed Central
Raggi, Sara; Ranocha, Philippe
2015-01-01
The structure of the cell wall has a major impact on plant growth and development, and alteration of cell wall structural components is often detrimental to biomass production. However, the molecular mechanisms responsible for these negative effects are largely unknown. Arabidopsis (Arabidopsis thaliana) plants with altered pectin composition because of either the expression of the Aspergillus niger polygalacturonase II (AnPGII; 35S:AnPGII plants) or a mutation in the QUASIMODO2 (QUA2) gene that encodes a putative pectin methyltransferase (qua2-1 plants), display severe growth defects. Here, we show that expression of Arabidopsis PEROXIDASE71 (AtPRX71), encoding a class III peroxidase, strongly increases in 35S:AnPGII and qua2-1 plants as well as in response to treatments with the cellulose synthase inhibitor isoxaben, which also impairs cell wall integrity. Analysis of atprx71 loss-of-function mutants and plants overexpressing AtPRX71 indicates that this gene negatively influences Arabidopsis growth at different stages of development, likely limiting cell expansion. The atprx71-1 mutation partially suppresses the dwarf phenotype of qua2-1, suggesting that AtPRX71 contributes to the growth defects observed in plants undergoing cell wall damage. Furthermore, AtPRX71 seems to promote the production of reactive oxygen species in qua2-1 plants as well as plants treated with isoxaben. We propose that AtPRX71 contributes to strengthen cell walls, therefore restricting cell expansion, during normal growth and in response to cell wall damage. PMID:26468518
19. 2004/09 Beginning Postsecondary Students Longitudinal Study (BPS:04/09). Full-Scale Methodology Report. NCES 2012-246
ERIC Educational Resources Information Center
Wine, Jennifer; Janson, Natasha; Wheeless, Sara
2011-01-01
This report describes and evaluates the methods and procedures used in the 2004/09 Beginning Postsecondary Students Longitudinal Study (BPS:04/09). BPS:04/09 is the second and final follow-up interview for the cohort of first-time beginning postsecondary students identified in the 2004 National Postsecondary Student Aid Study. For the first time…
20. The Role of the Plant-Specific ALTERED XYLOGLUCAN9 Protein in Arabidopsis Cell Wall Polysaccharide O-Acetylation1[OPEN
PubMed Central
Schultink, Alex; Naylor, Dan; Dama, Murali; Pauly, Markus
2015-01-01
A mutation in the ALTERED XYLOGLUCAN9 (AXY9) gene was found to be causative for the decreased xyloglucan acetylation phenotype of the axy9.1 mutant, which was identified in a forward genetic screen for Arabidopsis (Arabidopsis thaliana) mutants. The axy9.1 mutant also exhibits decreased O-acetylation of xylan, implying that the AXY9 protein has a broad role in polysaccharide acetylation. An axy9 insertional mutant exhibits severe growth defects and collapsed xylem, demonstrating the importance of wall polysaccharide O-acetylation for normal plant growth and development. Localization and topological experiments indicate that the active site of the AXY9 protein resides within the Golgi lumen. The AXY9 protein appears to be a component of the plant cell wall polysaccharide acetylation pathway, which also includes the REDUCED WALL ACETYLATION and TRICHOME BIREFRINGENCE-LIKE proteins. The AXY9 protein is distinct from the TRICHOME BIREFRINGENCE-LIKE proteins, reported to be polysaccharide acetyltransferases, but does share homology with them and other acetyltransferases, suggesting that the AXY9 protein may act to produce an acetylated intermediate that is part of the O-acetylation pathway. PMID:25681330
1. A Strategy against the Osteonecrosis of the Jaw Associated with Nitrogen-Containing Bisphosphonates (N-BPs): Attempts to Replace N-BPs with the Non-N-BP Etidronate.
PubMed
Oizumi, Takefumi; Yamaguchi, Kouji; Sato, Koichiro; Takahashi, Masato; Yoshimura, Gen; Otsuru, Hiroshi; Tsuchiya, Masahiro; Hagiwara, Yoshihiro; Itoi, Eiji; Sugawara, Shunji; Takahashi, Tetsu; Endo, Yasuo
2016-01-01
Bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) can occur when enhanced bone-resorptive diseases are treated with nitrogen-containing BPs (N-BPs). Having previously found, in mice, that the non-N-BP etidronate can (i) reduce the inflammatory/necrotic effects of N-BPs by inhibiting their intracellular entry and (ii) antagonize the binding of N-BPs to bone hydroxyapatite, we hypothesized that etidronate-replacement therapy (Eti-RT) might be useful for patients with, or at risk of, BRONJ. In the present study we examined this hypothesis. In each of 25 patients receiving N-BP treatment, the N-BP was discontinued when BRONJ was suspected and/or diagnosed. After consultation with the physician-in-charge and with the patient's informed consent, Eti-RT was instituted in one group according to its standard oral prescription. We retrospectively compared this Eti-RT group (11 patients) with a non-Eti-RT group (14 patients). The Eti-RT group (6 oral N-BP patients and 5 intravenous N-BP patients) and the non-Eti-RT group (5 oral N-BP patients and 9 intravenous N-BP patients) were all stage 2-3 BRONJ. Both in oral and intravenous N-BP patients (particularly in the former patients), Eti-RT promoted or tended to promote the separation and removal of sequestra and thereby promoted the recovery of soft-tissues, allowing them to cover the exposed jawbone. These results suggest that Eti-RT may be an effective choice for BRONJ caused by either oral or intravenous N-BPs and for BRONJ prevention, while retaining a level of anti-bone-resorption. Eti-RT may also be effective at preventing BRONJ in N-BP-treated patients at risk of BRONJ. However, prospective trials are still required.
2. DMSK: A practical 2400-bps receiver for the mobile satellite service: An MSAT-X Report
NASA Technical Reports Server (NTRS)
Davarian, F.; Simon, M. K.; Sumida, J.
1985-01-01
3. Binding of nitrogen-containing bisphosphonates (N-BPs) to the Trypanosoma cruzi farnesyl diphosphate synthase homodimer
SciTech Connect
Huang, Chuan-Hsiang; Gabelli, Sandra B.; Oldfield, Eric; Amzel, L. Mario
2010-11-15
Bisphosphonates (BPs) are a class of compounds that have been used extensively in the treatment of osteoporosis and malignancy-related hypercalcemia. Some of these compounds act through inhibition of farnesyl diphosphate synthase (FPPS), a key enzyme in the synthesis of isoprenoids. Recently, nitrogen-containing bisphosphonates (N-BPs) used in bone resorption therapy have been shown to be active against Trypanosoma cruzi, the parasite that causes American trypanosomiasis (Chagas disease), suggesting that they may be used as anti-trypanosomal agents. The crystal structures of TcFPPS in complex with substrate (isopentenyl diphosphate, IPP) and five N-BP inhibitors show that the C-1 hydroxyl and the nitrogen-containing groups of the inhibitors alter the binding of IPP and the conformation of two TcFPPS residues, Tyr94 and Gln167. Isothermal titration calorimetry experiments suggest that binding of the first N-BPs to the homodimeric TcFPPS changes the binding properties of the second site. This mechanism of binding of N-BPs to TcFPPS is different to that reported for the binding of the same compounds to human FPPS.
4. 2004/06 Beginning Postsecondary Students Longitudinal Study (BPS:04/06). Methodology Report. NCES 2008-184
ERIC Educational Resources Information Center
Cominole, Melissa; Wheeless, Sara; Dudley, Kristin; Franklin, Jeff; Wine, Jennifer
2007-01-01
The "2004/06 Beginning Postsecondary Students Longitudinal Study (BPS:04/06)" is sponsored by the U.S. Department of Education to respond to the need for a national, comprehensive database concerning issues students may face in enrollment, persistence, progress, and attainment in postsecondary education and in consequent early rates of…
5. Beginning Postsecondary Students Longitudinal Study: First Follow-Up 1996-98 (BPS:96/98) Methodology Report. Technical Report.
ERIC Educational Resources Information Center
Wine, Jennifer S.; Whitmore, Roy W.; Heuer, Ruth E.; Biber, Melissa; Pratt, Daniel J.
This report describes the methods and procedures used for the full-scale data collection effort of the Beginning Postsecondary Students Longitudinal Study First Follow-Up 1996-98 (BPS:96/98). These students, who started their postsecondary education during the 1995-96 academic year, were first interviewed during 1996 as part of the National…
6. Clinical presentation and treatment of bladder pain syndrome/interstitial cystitis (BPS/IC) in India.
PubMed
Mishra, Nagendra Nath
2015-10-01
Bladder pain syndrome/interstitial cystitis (BPS/IC) is a chronic disease characterized by pelvic pain urgency and frequency. Patients with severe symptoms lead a very miserable life. North American, European and Asian guidelines have been recently promulgated but they differ on many important issues. There is no consensus on its name, definition, investigations and management. Indian guidelines have also been developed and they give more importance to the symptoms in relation to micturition. Though initially believed to be rare or non-existent in India the situation has changed. In Indian patients the presentation is more or less same as the rest of the world but a large percentage have obstructive symptoms and unusual urinary symptoms. Anal discomfort is also common. In India the commonest investigation in all cases of lower urinary tract (LUT) dysfunction is ultrasonography of kidney ureter and bladder with measurement of the post void residual urine volume. Cystoscopy is also done in all the cases to rule out presence of tuberculosis or carcinoma in situ. Bladder pain syndrome/interstitial cystitis (BPS/IC) is not considered to be a clinical disease as it is difficult to rule out all differential diagnosis only from history. Hunner's lesion is very rare. Cystoscopy with hydro distension, oral therapy, intravesical therapy and surgical therapy form the back bone of management. It is difficult to know which treatment is best for a given patient. A staged protocol is followed and all the treatment modalities are applied to the patients in a sequential fashion-starting from the non-invasive to more invasive. Intravesical botox has not been found to be effective and there is no experience with interstim neuromodulation.
7. Clinical presentation and treatment of bladder pain syndrome/interstitial cystitis (BPS/IC) in India
PubMed Central
2015-01-01
Bladder pain syndrome/interstitial cystitis (BPS/IC) is a chronic disease characterized by pelvic pain urgency and frequency. Patients with severe symptoms lead a very miserable life. North American, European and Asian guidelines have been recently promulgated but they differ on many important issues. There is no consensus on its name, definition, investigations and management. Indian guidelines have also been developed and they give more importance to the symptoms in relation to micturition. Though initially believed to be rare or non-existent in India the situation has changed. In Indian patients the presentation is more or less same as the rest of the world but a large percentage have obstructive symptoms and unusual urinary symptoms. Anal discomfort is also common. In India the commonest investigation in all cases of lower urinary tract (LUT) dysfunction is ultrasonography of kidney ureter and bladder with measurement of the post void residual urine volume. Cystoscopy is also done in all the cases to rule out presence of tuberculosis or carcinoma in situ. Bladder pain syndrome/interstitial cystitis (BPS/IC) is not considered to be a clinical disease as it is difficult to rule out all differential diagnosis only from history. Hunner’s lesion is very rare. Cystoscopy with hydro distension, oral therapy, intravesical therapy and surgical therapy form the back bone of management. It is difficult to know which treatment is best for a given patient. A staged protocol is followed and all the treatment modalities are applied to the patients in a sequential fashion—starting from the non-invasive to more invasive. Intravesical botox has not been found to be effective and there is no experience with interstim neuromodulation. PMID:26816851
8. On domain decomposition preconditioner of BPS type for finite element discretizations of 3D elliptic equations
NASA Astrophysics Data System (ADS)
Korneev, V. G.
2012-09-01
BPS is a well known an efficient and rather general domain decomposition Dirichlet-Dirichlet type preconditioner, suggested in the famous series of papers Bramble, Pasciak and Schatz (1986-1989). Since then, it has been serving as the origin for the whole family of domain decomposition Dirichlet-Dirichlet type preconditioners-solvers as for h so hp discretizations of elliptic problems. For its original version, designed for h discretizations, the named authors proved the bound O(1 + log2 H/ h) for the relative condition number under some restricting conditions on the domain decomposition and finite element discretization. Here H/ h is the maximal relation of the characteristic size H of a decomposition subdomain to the mesh parameter h of its discretization. It was assumed that subdomains are images of the reference unite cube by trilinear mappings. Later similar bounds related to h discretizations were proved for more general domain decompositions, defined by means of coarse tetrahedral meshes. These results, accompanied by the development of some special tools of analysis aimed at such type of decompositions, were summarized in the book of Toselli and Widlund (2005). This paper is also confined to h discretizations. We further expand the range of admissible domain decompositions for constructing BPS preconditioners, in which decomposition subdomains can be convex polyhedrons, satisfying some conditions of shape regularity. We prove the bound for the relative condition number with the same dependence on H/ h as in the bound given above. Along the way to this result, we simplify the proof of the so called abstract bound for the relative condition number of the domain decomposition preconditioner. In the part, related to the analysis of the interface sub-problem preconditioning, our technical tools are generalization of those used by Bramble, Pasciak and Schatz.
9. The Cell Wall Arabinose-Deficient Arabidopsis thaliana Mutant murus5 Encodes a Defective Allele of REVERSIBLY GLYCOSYLATED POLYPEPTIDE21[OPEN
PubMed Central
Dugard, Christopher K.; Olek, Anna T.; Cooper, Bruce R.
2016-01-01
Traditional marker-based mapping and next-generation sequencing was used to determine that the Arabidopsis (Arabidopsis thaliana) low cell wall arabinose mutant murus5 (mur5) encodes a defective allele of REVERSIBLY GLYCOSYLATED POLYPEPTIDE2 (RGP2). Marker analysis of 13 F2 confirmed mutant progeny from a recombinant mapping population gave a rough map position on the upper arm of chromosome 5, and deep sequencing of DNA from these 13 lines gave five candidate genes with G→A (C→T) transitions predicted to result in amino acid changes. Of these five, only insertional mutant alleles of RGP2, a gene that encodes a UDP-arabinose mutase that interconverts UDP-arabinopyranose and UDP-arabinofuranose, exhibited the low cell wall arabinose phenotype. The identities of mur5 and two SALK insertional alleles were confirmed by allelism tests and overexpression of wild-type RGP2 complementary DNA placed under the control of the 35S promoter in the three alleles. The mur5 mutation results in the conversion of cysteine-257 to tyrosine-257 within a conserved hydrophobic cluster predicted to be distal to the active site and essential for protein stability and possible heterodimerization with other isoforms of RGP. PMID:27217494
10. Determining the Subcellular Location of Synthesis and Assembly of the Cell Wall Polysaccharide (1,3; 1,4)-β-d-Glucan in Grasses[OPEN
PubMed Central
Wilson, Sarah M.; Ho, Yin Ying; Lampugnani, Edwin R.; Van de Meene, Allison M.L.; Bain, Melissa P.; Bacic, Antony; Doblin, Monika S.
2015-01-01
The current dogma for cell wall polysaccharide biosynthesis is that cellulose (and callose) is synthesized at the plasma membrane (PM), whereas matrix phase polysaccharides are assembled in the Golgi apparatus. We provide evidence that (1,3;1,4)-β-d-glucan (mixed-linkage glucan [MLG]) does not conform to this paradigm. We show in various grass (Poaceae) species that MLG-specific antibody labeling is present in the wall but absent over Golgi, suggesting it is assembled at the PM. Antibodies to the MLG synthases, cellulose synthase-like F6 (CSLF6) and CSLH1, located CSLF6 to the endoplasmic reticulum, Golgi, secretory vesicles, and the PM and CSLH1 to the same locations apart from the PM. This pattern was recreated upon expression of VENUS-tagged barley (Hordeum vulgare) CSLF6 and CSLH1 in Nicotiana benthamiana leaves and, consistent with our biochemical analyses of native grass tissues, shown to be catalytically active with CSLF6 and CSLH1 in PM-enriched and PM-depleted membrane fractions, respectively. These data support a PM location for the synthesis of MLG by CSLF6, the predominant enzymatically active isoform. A model is proposed to guide future experimental approaches to dissect the molecular mechanism(s) of MLG assembly. PMID:25770111
11. The Target of β-Expansin EXPB1 in Maize Cell Walls from Binding and Solid-State NMR Studies1[OPEN
PubMed Central
Wang, Tuo; Hong, Mei
2016-01-01
The wall-loosening actions of β-expansins are known primarily from studies of EXPB1 extracted from maize (Zea mays) pollen. EXPB1 selectively loosens cell walls (CWs) of grasses, but its specific binding target is unknown. We characterized EXPB1 binding to sequentially extracted maize CWs, finding that the protein primarily binds glucuronoarabinoxylan (GAX), the major matrix polysaccharide in grass CWs. This binding is strongly reduced by salts, indicating that it is predominantly electrostatic in nature. For direct molecular evidence of EXPB1 binding, we conducted solid-state nuclear magnetic resonance experiments using paramagnetic relaxation enhancement (PRE), which is sensitive to distances between unpaired electrons and nuclei. By mixing 13C-enriched maize CWs with EXPB1 functionalized with a Mn2+ tag, we measured Mn2+-induced PRE. Strong 1H and 13C PREs were observed for the carboxyls of GAX, followed by more moderate PREs for carboxyl groups in homogalacturonan and rhamnogalacturonan-I, indicating that EXPB1 preferentially binds GAX. In contrast, no PRE was observed for cellulose, indicating very weak interaction of EXPB1 with cellulose. Dynamics experiments show that EXPB1 changes GAX mobility in a complex manner: the rigid fraction of GAX became more rigid upon EXPB1 binding while the dynamic fraction became more mobile. Combining these data with previous results, we propose that EXPB1 loosens grass CWs by disrupting noncovalent junctions between highly substituted GAX and GAX of low substitution, which binds cellulose. This study provides molecular evidence of β-expansin’s target in grass CWs and demonstrates a new strategy for investigating ligand binding for proteins that are difficult to express heterologously. PMID:27729469
12. Comparative Evaluation of Platelet-Rich Fibrin Biomaterial and Open Flap Debridement in the Treatment of Two and Three Wall Intrabony Defects
PubMed Central
Ajwani, Himanshu; Shetty, Sharath; Gopalakrishnan, Dharmarajan; Kathariya, Rahul; Kulloli, Anita; Dolas, R S; Pradeep, A R
2015-01-01
Background: Platelet-rich concentrates are the most widely used regenerative biomaterials. Stimulation and acceleration of soft and hard tissue healing are due to local and continuous delivery of growth factors and proteins, mimicking the needs of the physiological wound healing and reparative tissue processes. This article aims to evaluate the clinical efficacy of open flap debridement (OFD) with or without platelet-rich fibrin (PRF) in the treatment of intrabony defects. Materials and Methods: Twenty subjects with forty intrabony defects were treated with either autologous PRF with open-flap debridement (test, n = 20) or open-flap debridement alone (control, n = 20). Soft tissue parameters included: Plaque index, sulcus bleeding index, probing depth, relative attachment level and gingival marginal level (GML). The hard tissue parameters included-distances from: Cement enamel junction to the base of the defect (CEJ-BOD): Alveolar crest to the base of the defect (AC-BOD): And CEJ to AC. The parameters were recorded at baseline and at 9 months postoperatively calculated using standardized radiographs by image-analysis software. Results: Statistically significant (0.005*) intragroup improvements were seen with all the hard and soft parameters in both test and control groups, except for GML. Statistically significant improvements were seen with the mean defect fill (CEJ-BOD and AC-BOD) (P = 0.003*) when intergroup comparisons were made. Conclusions: Adjunctive use of PRF with OFD significantly improves defect fill when compared to OFD alone. PRF has consistently been showing regenerative potential; it is simple, easy and inexpensive biomaterial compared with bone grafts. PMID:25954068
13. RNA-Seq Links the Transcription Factors AINTEGUMENTA and AINTEGUMENTA-LIKE6 to Cell Wall Remodeling and Plant Defense Pathways1[OPEN
PubMed Central
Bequette, Carlton J.; Fu, Zheng Qing; Loraine, Ann E.
2016-01-01
AINTEGUMENTA (ANT) and AINTEGUMENTA-LIKE6 (AIL6) are two related transcription factors in Arabidopsis (Arabidopsis thaliana) that have partially overlapping roles in several aspects of flower development, including floral organ initiation, identity specification, growth, and patterning. To better understand the biological processes regulated by these two transcription factors, we performed RNA sequencing (RNA-Seq) on ant ail6 double mutants. We identified thousands of genes that are differentially expressed in the double mutant compared with the wild type. Analyses of these genes suggest that ANT and AIL6 regulate floral organ initiation and growth through modifications to the cell wall polysaccharide pectin. We found reduced levels of demethylesterified homogalacturonan and altered patterns of auxin accumulation in early stages of ant ail6 flower development. The RNA-Seq experiment also revealed cross-regulation of AIL gene expression at the transcriptional level. The presence of a number of overrepresented Gene Ontology terms related to plant defense in the set of genes differentially expressed in ant ail6 suggest that ANT and AIL6 also regulate plant defense pathways. Furthermore, we found that ant ail6 plants have elevated levels of two defense hormones: salicylic acid and jasmonic acid, and show increased resistance to the bacterial pathogen Pseudomonas syringae. These results suggest that ANT and AIL6 regulate biological pathways that are critical for both development and defense. PMID:27208279
14. Transcriptome Profiling of the Green Alga Spirogyra pratensis (Charophyta) Suggests an Ancestral Role for Ethylene in Cell Wall Metabolism, Photosynthesis, and Abiotic Stress Responses1[OPEN
PubMed Central
2016-01-01
It is well known that ethylene regulates a diverse set of developmental and stress-related processes in angiosperms, yet its roles in early-diverging embryophytes and algae are poorly understood. Recently, it was shown that ethylene functions as a hormone in the charophyte green alga Spirogyra pratensis. Since land plants evolved from charophytes, this implies conservation of ethylene as a hormone in green plants for at least 450 million years. However, the physiological role of ethylene in charophyte algae has remained unknown. To gain insight into ethylene responses in Spirogyra, we used mRNA sequencing to measure changes in gene expression over time in Spirogyra filaments in response to an ethylene treatment. Our analyses show that at the transcriptional level, ethylene predominantly regulates three processes in Spirogyra: (1) modification of the cell wall matrix by expansins and xyloglucan endotransglucosylases/hydrolases, (2) down-regulation of chlorophyll biosynthesis and photosynthesis, and (3) activation of abiotic stress responses. We confirmed that the photosynthetic capacity and chlorophyll content were reduced by an ethylene treatment and that several abiotic stress conditions could stimulate cell elongation in an ethylene-dependent manner. We also found that the Spirogyra transcriptome harbors only 10 ethylene-responsive transcription factor (ERF) homologs, several of which are regulated by ethylene. These results provide an initial understanding of the hormonal responses induced by ethylene in Spirogyra and help to reconstruct the role of ethylene in ancestral charophytes prior to the origin of land plants. PMID:27489312
15. BPS-like bound and thermodynamics of the charged BTZ black hole
NASA Astrophysics Data System (ADS)
Cadoni, Mariano; Monni, Cristina
2009-07-01
The charged Bañados-Teitelboim-Zanelli (BTZ) black hole is plagued by several pathologies: (a) Divergent boundary terms are present in the action; hence, we have a divergent black-hole mass. (b) Once a finite, renormalized, mass M is defined, black-hole states exist for arbitrarily negative values of M. (c) There is no upper bound on the charge Q. We show that these pathological features are an artifact of the renormalization procedure. They can be completely removed by using an alternative renormalization scheme leading to a different definition M0 of the black-hole mass, which is the total energy inside the horizon. The new mass satisfies a BPS-like bound M0≥(π)/(2)Q2, and the heat capacity of the hole is positive. We also discuss the black-hole thermodynamics that arises when M0 is interpreted as the internal energy of the system. We show, using three independent approaches (black-hole thermodynamics, Einstein equations, and Euclidean action formulation), that M0 satisfies the first law if a term describing the mechanical work done by the electrostatic pressure is introduced.
16. Diet and its role in interstitial cystitis/bladder pain syndrome (IC/BPS) and comorbid conditions.
PubMed
Friedlander, Justin I; Shorter, Barbara; Moldwin, Robert M
2012-06-01
What's known on the subject? and What does the study add? Nearly 90% of patients with interstitial cystitis/bladder pain syndrome (IC/BPS) report sensitivities to a wide variety of dietary comestibles. Current questionnaire-based literature suggests that citrus fruits, tomatoes, vitamin C, artificial sweeteners, coffee, tea, carbonated and alcoholic beverages, and spicy foods tend to exacerbate symptoms, while calcium glycerophosphate and sodium bicarbonate tend to improve symptoms. At present we recommend employing a controlled method to determine dietary sensitivities, such as an elimination diet, in order to identify sensitivities while at the same time maintain optimal nutritional intake. We review current literature with regard to diet's effect upon IC/BPS and common comorbidities (irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome, neuropathic pain, vulvodynia, and headache) with a focus upon questionnaire-based investigations. We discuss the pathologic mechanisms that may link diet and IC/BPS related-pain, concentrating upon specific comestibles such as acidic foods, foods high in potassium, caffeine, and alcohol. Up to 90% of patients with interstitial cystitis/bladder pain syndrome (IC/BPS) report sensitivities to a wide variety of comestibles. Pathological mechanisms suggested to be responsible for the relationship between dietary intake and symptom exacerbation include peripheral and/or central neural upregulation, bladder epithelial dysfunction, and organ 'cross-talk', amongst others. Current questionnaire-based data suggests that citrus fruits, tomatoes, vitamin C, artificial sweeteners, coffee, tea, carbonated and alcoholic beverages, and spicy foods tend to exacerbate symptoms, while calcium glycerophosphate and sodium bicarbonate tend to improve symptoms. Specific comestible sensitivities varied between patients and may have been influenced by comorbid conditions. This suggests that a controlled method to determine dietary
17. GmEXPB2, a Cell Wall β-Expansin, Affects Soybean Nodulation through Modifying Root Architecture and Promoting Nodule Formation and Development1[OPEN
PubMed Central
Li, Xinxin; Zhao, Jing; Tan, Zhiyuan; Liao, Hong
2015-01-01
Nodulation is an essential process for biological nitrogen (N2) fixation in legumes, but its regulation remains poorly understood. Here, a β-expansin gene, GmEXPB2, was found to be critical for soybean (Glycine max) nodulation. GmEXPB2 was preferentially expressed at the early stage of nodule development. β-Glucuronidase staining further showed that GmEXPB2 was mainly localized to the nodule vascular trace and nodule vascular bundles, as well as nodule cortical and parenchyma cells, suggesting that GmEXPB2 might be involved in cell wall modification and extension during nodule formation and development. Overexpression of GmEXPB2 dramatically modified soybean root architecture, increasing the size and number of cortical cells in the root meristematic and elongation zones and expanding root hair density and size of the root hair zone. Confocal microscopy with green fluorescent protein-labeled rhizobium USDA110 cells showed that the infection events were significantly enhanced in the GmEXPB2-overexpressing lines. Moreover, nodule primordium development was earlier in overexpressing lines compared with wild-type plants. Thereby, overexpression of GmEXPB2 in either transgenic soybean hairy roots or whole plants resulted in increased nodule number, nodule mass, and nitrogenase activity and thus elevated plant N and phosphorus content as well as biomass. In contrast, suppression of GmEXPB2 in soybean transgenic composite plants led to smaller infected cells and thus reduced number of big nodules, nodule mass, and nitrogenase activity, thereby inhibiting soybean growth. Taken together, we conclude that GmEXPB2 critically affects soybean nodulation through modifying root architecture and promoting nodule formation and development and subsequently impacts biological N2 fixation and growth of soybean. PMID:26432877
18. Comparison of objectively measured motor behavior with ratings of the motor behavior domain of the Bern Psychopathology Scale (BPS) in schizophrenia.
PubMed
Bracht, Tobias; Heidemeyer, Kristine; Koschorke, Philipp; Horn, Helge; Razavi, Nadja; Wopfner, Alexander; Strik, Werner; Walther, Sebastian
2012-07-30
Motor symptoms in schizophrenia occur frequently and are relevant to diagnosis and antipsychotic therapy. To date motor symptoms are difficult to assess and their pathobiology is a widely unresolved issue. The Bern Psychopathology Scale for the assessment of system-specific psychotic symptoms (BPS) was designed to identify homogenous patient groups by focusing on three domains: language, affectivity and motor behavior. The present study aimed to validate the motor behavior domain of the BPS using wrist actigraphy. In total, 106 patients were rated with the BPS and underwent 24 h continuous actigraphy recording. The ratings of the global severity of the motor behavior domain (GSM) as well as the quantitative and the subjective items of the motor behavior domain of the BPS were significantly associated with actigraphic variables. In contrast, the qualitative items of the motor domain failed to show an association with actigraphy. Likewise, scores of the language and the affectivity domains were not related to actigraphic measures. In conclusion, we provided substantial external validity for global, quantitative and subjective ratings of the BPS motor behavior domain. Thus, the BPS is suitable to assess the dimension of quantitative motor behavior in the schizophrenia spectrum.
19. Wall-Crossing, Free Fermions and Crystal Melting
NASA Astrophysics Data System (ADS)
Sułkowski, Piotr
2011-01-01
We describe wall-crossing for local, toric Calabi-Yau manifolds without compact four-cycles, in terms of free fermions, vertex operators, and crystal melting. Firstly, to each such manifold we associate two states in the free fermion Hilbert space. The overlap of these states reproduces the BPS partition function corresponding to the non-commutative Donaldson-Thomas invariants, given by the modulus square of the topological string partition function. Secondly, we introduce the wall-crossing operators which represent crossing the walls of marginal stability associated to changes of the B-field through each two-cycle in the manifold. BPS partition functions in non-trivial chambers are given by the expectation values of these operators. Thirdly, we discuss crystal interpretation of such correlators for this whole class of manifolds. We describe evolution of these crystals upon a change of the moduli, and find crystal interpretation of the flop transition and the DT/PT transition. The crystals which we find generalize and unify various other Calabi-Yau crystal models which appeared in literature in recent years.
20. Black hole information in string theory: Non-BPS microstates and superstrata
NASA Astrophysics Data System (ADS)
Niehoff, Benjamin E.
In this thesis we explore two novel directions in the quest for 3-charge "black hole microstate geometries", which are smooth, horizon-free supergravity solutions in 5 or more dimensions that correspond to the microstates of black holes. First we find two infinite families of smooth non-BPS microstates using the "floating brane ansatz" method in 5 dimensions, based on a class of Kahler metrics studied by LeBrun. The first set of solutions is based on the LeBrun-Burns subclass, which turn out to have a trivial flux, leading to trivial bubble equations. The second set of solutions is based on the more general LeBrun metrics, which have non-trivial flux, and we find non-trivial bubble equations. In both cases, solutions are asymptotic to warped, rotating AdS2 x S 3. Second, we realize two important steps toward the construction of superstrata, which are 3-charge, 2-dipole-charge smooth supergravity solutions that fluctuate as an arbitrary function of two variables. In one case, we find solutions that depend on functions of two variables; however they lack the necessary KKM charge to make them smooth. In the second case, we construct smooth solutions with KKM charge turned on, but in a restricted class that allows them only to depend on arbitrary functions of one variable. Nevertheless, we show that this one variable can be oriented in an arbitrary way inside a 2-torus, and many sources with different orientations inside the T2 can be combined via superposition.
1. Escherichia coli Protein Expression System for Acetylcholine Binding Proteins (AChBPs)
PubMed Central
Abraham, Nikita; Paul, Blessy; Ragnarsson, Lotten; Lewis, Richard J.
2016-01-01
Nicotinic acetylcholine receptors (nAChR) are ligand gated ion channels, identified as therapeutic targets for a range of human diseases. Drug design for nAChR related disorders is increasingly using structure-based approaches. Many of these structural insights for therapeutic lead development have been obtained from co-crystal structures of nAChR agonists and antagonists with the acetylcholine binding protein (AChBP). AChBP is a water soluble, structural and functional homolog of the extracellular, ligand-binding domain of nAChRs. Currently, AChBPs are recombinantly expressed in eukaryotic expression systems for structural and biophysical studies. Here, we report the establishment of an Escherichia coli (E. coli) expression system that significantly reduces the cost and time of production compared to the existing expression systems. E. coli can efficiently express unglycosylated AChBP for crystallography and makes the expression of isotopically labelled forms feasible for NMR. We used a pHUE vector containing an N-terminal His-tagged ubiquitin fusion protein to facilitate AChBP expression in the soluble fractions, and thus avoid the need to recover protein from inclusion bodies. The purified protein yield obtained from the E. coli expression system is comparable to that obtained from existing AChBP expression systems. E. coli expressed AChBP bound nAChR agonists and antagonists with affinities matching those previously reported. Thus, the E. coli expression system significantly simplifies the expression and purification of functional AChBP for structural and biophysical studies. PMID:27304486
2. Evaluation of the scale dependent dynamic SGS model in the open source code caffa3d.MBRi in wall-bounded flows
NASA Astrophysics Data System (ADS)
Draper, Martin; Usera, Gabriel
2015-04-01
The Scale Dependent Dynamic Model (SDDM) has been widely validated in large-eddy simulations using pseudo-spectral codes [1][2][3]. The scale dependency, particularly the potential law, has been proved also in a priori studies [4][5]. To the authors' knowledge there have been only few attempts to use the SDDM in finite difference (FD) and finite volume (FV) codes [6][7], finding some improvements with the dynamic procedures (scale independent or scale dependent approach), but not showing the behavior of the scale-dependence parameter when using the SDDM. The aim of the present paper is to evaluate the SDDM in the open source code caffa3d.MBRi, an updated version of the code presented in [8]. caffa3d.MBRi is a FV code, second-order accurate, parallelized with MPI, in which the domain is divided in unstructured blocks of structured grids. To accomplish this, 2 cases are considered: flow between flat plates and flow over a rough surface with the presence of a model wind turbine, taking for this case the experimental data presented in [9]. In both cases the standard Smagorinsky Model (SM), the Scale Independent Dynamic Model (SIDM) and the SDDM are tested. As presented in [6][7] slight improvements are obtained with the SDDM. Nevertheless, the behavior of the scale-dependence parameter supports the generalization of the dynamic procedure proposed in the SDDM, particularly taking into account that no explicit filter is used (the implicit filter is unknown). [1] F. Porté-Agel, C. Meneveau, M.B. Parlange. "A scale-dependent dynamic model for large-eddy simulation: application to a neutral atmospheric boundary layer". Journal of Fluid Mechanics, 2000, 415, 261-284. [2] E. Bou-Zeid, C. Meneveau, M. Parlante. "A scale-dependent Lagrangian dynamic model for large eddy simulation of complex turbulent flows". Physics of Fluids, 2005, 17, 025105 (18p). [3] R. Stoll, F. Porté-Agel. "Dynamic subgrid-scale models for momentum and scalar fluxes in large-eddy simulations of
3. Comparative study of the microvascular blood flow in the intestinal wall, wound contraction and fluid evacuation during negative pressure wound therapy in laparostomy using the V.A.C. abdominal dressing and the ABThera open abdomen negative pressure therapy system.
PubMed
Lindstedt, Sandra; Malmsjö, Malin; Hlebowicz, Joanna; Ingemansson, Richard
2015-02-01
This study aimed to compare the changes in microvascular blood flow in the small intestinal wall, wound contraction and fluid evacuation, using the established V.A.C. abdominal dressing (VAC dressing) and a new abdominal dressing, the ABThera open abdomen negative pressure therapy system (ABThera dressing), in negative pressure wound therapy (NPWT). Midline incisions were made in 12 pigs that were subjected to treatment with NPWT using the VAC or ABThera dressing. The microvascular blood flow in the intestinal wall was measured before and after the application of topical negative pressures of −50, −75 and −125mmHg using laser Doppler velocimetry. Wound contraction and fluid evacuation were also measured. Baseline blood flow was defined as 100% in all settings. The blood flow was significantly reduced to 64·6±6·7% (P <0·05) after the application of −50mmHg using the VAC dressing, and to 65·3±9·6% (P <0·05) after the application of −50mmHg using the ABThera dressing. The blood flow was significantly reduced to 39·6±6·7% (P <0·05) after the application of −125mmHg using VAC and to 40·5±6·2% (P <0·05) after the application of −125mmHg using ABThera. No significant difference in reduction in blood flow could be observed between the two groups. The ABThera system afforded significantly better fluid evacuation from the wound, better drainage of the abdomen and better wound contraction than the VAC dressing.
4. Wall Turbulence.
ERIC Educational Resources Information Center
Hanratty, Thomas J.
1980-01-01
This paper gives an account of research on the structure of turbulence close to a solid boundary. Included is a method to study the flow close to the wall of a pipe without interferring with it. (Author/JN)
5. All three-loop four-point correlators of half-BPS operators in planar N = 4 SYM
NASA Astrophysics Data System (ADS)
Chicherin, Dmitry; Drummond, James; Heslop, Paul; Sokatchev, Emery
2016-08-01
We obtain the planar correlation function of four half-BPS operators of arbitrary weights, up to three loops. Our method exploits only elementary properties of the integrand of the planar correlator, such as its symmetries and singularity structure. This allows us to write down a general ansatz for the integrand. The coefficients in the ansatz are fixed by means of a powerful light-cone OPE relation between correlators with different weights. Our result is formulated in terms of a limited number of functions built from known one-, two- and three-loop conformal integrals. These results are useful for checking recent integrability predictions for the OPE structure constants.
6. The IUPHAR/BPS Guide to PHARMACOLOGY in 2016: towards curated quantitative interactions between 1300 protein targets and 6000 ligands
PubMed Central
Southan, Christopher; Sharman, Joanna L.; Benson, Helen E.; Faccenda, Elena; Pawson, Adam J.; Alexander, Stephen P. H.; Buneman, O. Peter; Davenport, Anthony P.; McGrath, John C.; Peters, John A.; Spedding, Michael; Catterall, William A.; Fabbro, Doriano; Davies, Jamie A.
2016-01-01
The IUPHAR/BPS Guide to PHARMACOLOGY (GtoPdb, http://www.guidetopharmacology.org) provides expert-curated molecular interactions between successful and potential drugs and their targets in the human genome. Developed by the International Union of Basic and Clinical Pharmacology (IUPHAR) and the British Pharmacological Society (BPS), this resource, and its earlier incarnation as IUPHAR-DB, is described in our 2014 publication. This update incorporates changes over the intervening seven database releases. The unique model of content capture is based on established and new target class subcommittees collaborating with in-house curators. Most information comes from journal articles, but we now also index kinase cross-screening panels. Targets are specified by UniProtKB IDs. Small molecules are defined by PubChem Compound Identifiers (CIDs); ligand capture also includes peptides and clinical antibodies. We have extended the capture of ligands and targets linked via published quantitative binding data (e.g. Ki, IC50 or Kd). The resulting pharmacological relationship network now defines a data-supported druggable genome encompassing 7% of human proteins. The database also provides an expanded substrate for the biennially published compendium, the Concise Guide to PHARMACOLOGY. This article covers content increase, entity analysis, revised curation strategies, new website features and expanded download options. PMID:26464438
7. The IUPHAR/BPS Guide to PHARMACOLOGY in 2016: towards curated quantitative interactions between 1300 protein targets and 6000 ligands.
PubMed
Southan, Christopher; Sharman, Joanna L; Benson, Helen E; Faccenda, Elena; Pawson, Adam J; Alexander, Stephen P H; Buneman, O Peter; Davenport, Anthony P; McGrath, John C; Peters, John A; Spedding, Michael; Catterall, William A; Fabbro, Doriano; Davies, Jamie A
2016-01-04
The IUPHAR/BPS Guide to PHARMACOLOGY (GtoPdb, http://www.guidetopharmacology.org) provides expert-curated molecular interactions between successful and potential drugs and their targets in the human genome. Developed by the International Union of Basic and Clinical Pharmacology (IUPHAR) and the British Pharmacological Society (BPS), this resource, and its earlier incarnation as IUPHAR-DB, is described in our 2014 publication. This update incorporates changes over the intervening seven database releases. The unique model of content capture is based on established and new target class subcommittees collaborating with in-house curators. Most information comes from journal articles, but we now also index kinase cross-screening panels. Targets are specified by UniProtKB IDs. Small molecules are defined by PubChem Compound Identifiers (CIDs); ligand capture also includes peptides and clinical antibodies. We have extended the capture of ligands and targets linked via published quantitative binding data (e.g. Ki, IC50 or Kd). The resulting pharmacological relationship network now defines a data-supported druggable genome encompassing 7% of human proteins. The database also provides an expanded substrate for the biennially published compendium, the Concise Guide to PHARMACOLOGY. This article covers content increase, entity analysis, revised curation strategies, new website features and expanded download options.
8. 'Stucco' Walls
NASA Technical Reports Server (NTRS)
2004-01-01
This projected mosaic image, taken by the microscopic imager, an instrument located on the Mars Exploration Rover Opportunity 's instrument deployment device, or 'arm,' shows the partial clotting or cement-like properties of the sand-sized grains within the trench wall. The area in this image measures approximately 3 centimeters (1.2 inches) wide and 5 centimeters (2 inches) tall.(This image also appears as an inset on a separate image from the rover's navigation camera, showing the location of this particular spot within the trench wall.)
9. Wall Art
ERIC Educational Resources Information Center
McGinley, Connie Q.
2004-01-01
The author of this article, an art teacher at Monarch High School in Louisville, Colorado, describes how her experience teaching in a new school presented an exciting visual challenge for an art teacher--monotonous brick walls just waiting for decoration. This school experienced only minimal instances of graffiti, but as an art teacher, she did…
10. 48. GENERAL VIEW OF SOUTHWEST, FIRST FLOOR ROOM, EAST WALL, ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
48. GENERAL VIEW OF SOUTHWEST, FIRST FLOOR ROOM, EAST WALL, WITH SECRET DOOR TO BOXED STAIRWAY TO ROOM ABOVE OPEN IN PANELLED WALL - Montpelier, Montpelier Drive & State Route 197, Laurel, Prince George's County, MD
11. Endocrine Activity of Bisphenol S (BPS) Using In Vitro Estrogenic/Anti-Androgenic Transcriptional Activation Assays and the In Vivo Uterotrophic Assay
EPA Science Inventory
Bisphenol A (BPA) is gradually being phased out of many consumer products and processes leading to potential increases in human and environmental exposures to relatively understudied replacement compounds, including Bisphenol S (BPS). Research from our lab has shown that BPA and...
12. The Most General BPS Black Hole from Type II String Theory on a Six-Torus the Macroscopic-Microscopic Correspondence
NASA Astrophysics Data System (ADS)
Bertolini, M.; Trigiante, M.
2002-12-01
BPS black hole solutions in supergravity have been playing an important role in probing non-perturbative superstring dualities. The largest of these dualities is the conjectured U-duality, implemented by a discrete group of transformations U(Z), which represents the ultimate connection between all known superstring theories realized on various backgrounds. This picture suggests the existence of a unique fundamental quantum theory underlying the superstring theories, of which U-duality is an exact symmetry. In [1] this U-duality was conjectured to be encoded in the largest global symmetry group of the the field equations and Bianchi identities in the low-energy effective supergravity theory, which is described at classical level by a continuous semisimple Lie group U. The degree of supersymmetry preserved by BPS black holes in supergravity protects their physical quantities to a certain extent from quantum corrections so that they can be thought to correspond to solutions of superstring theory. Since moreover the BPS condition is U-duality invariant, these solutions naturally span an orbit of the U-duality group, which is a continuous collection of solutions at classical supergravity level and a discrete set at the superstring level. Supergravity represents the framework in which these orbits can be studied in most detail . A fruitful strategy therefore in order to study the microscopic features of BPS black holes in relation to their U-duality invariant properties would be to keep track in a precise mathematical fashion of the microscopic description of BPS black holes at this low-energy level and moreover to focus on the most general BPS black hole in a certain orbit modulo U-duality transformations, namely the generating solution. This is the main philosophy motivating the research project carried out in [3,4,5] where a macroscopic (supergravity) starting point was adopted for a systematic microscopic analysis of
13. The important role of physicians in addressing the psychological aspects of Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS): A qualitative analysis
PubMed Central
Kanter, Gregory; Volpe, Katherine A; Dunivan, Gena C; Cichowski, Sara B; Jeppson, Peter C; Rogers, Rebecca G; Komesu, Yuko M
2016-01-01
Introduction Interstitial cystitis/bladder pain syndrome (IC/BPS) is a poorly understood source of chronic pain causing significant morbidity, with variable treatment success. Despite the need to understand patient perspectives in chronic pain, there is a paucity of qualitative data for IC/BPS. We aimed to acquire information regarding patient experience with IC/BPS symptoms and with their medical care to elicit suggestions to improve patient satisfaction with that care. Methods Fifteen women with IC/PBS participated in a total of four focus groups. Sessions were recorded, transcribed, and information was de-identified. Focus groups were conducted until thematic saturation was reached. All transcripts were coded and analyzed by a minimum of 3 independent physician reviewers. Investigators identified emergent themes and concepts using grounded theory methodology. Results Participant’s mean age was 52.6 years with an average IC/BPS duration of 6.3 years. Thematic saturation was reached after 4 focus groups. We identified three emergent patient experience concepts; IC/PBS is debilitating, the disease course is unpredictable and unrelenting, and patients experience significant isolation. Importantly, suicidal ideation was expressed in each group. Patients voiced strong preference for physicians who provided education regarding the condition, an array of treatment options, presented organized treatment plans and offered optimism and hope regarding treatment outcomes. Conclusions Our study presents novel findings of the importance of patient-physician interaction in IC/BPS and reinforces the tremendous disability and burden of this disease, which frequently manifests in suicidal ideation. Patients preferred organized treatment plans with diverse choices, and providers who offered hope in dealing with their condition. PMID:27581769
14. Cooling wall
SciTech Connect
Nosenko, V.I.
1995-07-01
Protecting the shells of blast furnaces is being resolved by installing cast iron cooling plates. The cooling plates become non-operational in three to five years. The problem is that defects occur in manufacturing the cooling plates. With increased volume and intensity of work placed on blast furnaces, heat on the cast iron cooling plates reduces their reliability that limits the interim repair period of blast furnaces. Scientists and engineers from the Ukraine studied this problem for several years, developing a new method of cooling the blast furnace shaft called the cooling wall. Traditional cast iron plates were replaced by a screen of steel tubes, with the area between the tubes filled with fireproof concrete. Before placing the newly developed furnace shaft into operation, considerable work was completed such as theoretical calculations, design, research of temperature fields and tension. Continual testing over many years confirms the value of this research in operating blast furnaces. The cooling wall works with water cooling as well as vapor cooling and is operating in 14 blast furnaces in the Ukraine and two in Russia, and has operated for as long as 14 years.
15. The Open University Opens.
ERIC Educational Resources Information Center
Tunstall, Jeremy, Ed.
Conceived by the British Labor Government in the 1960's the Open University was viewed as a way to extend higher education to Britain's working class, but enrollment figures in classes that represent traditional academic disciplines show that the student population is predominantly middle class. Bringing education into the home presents numerous…
16. Ultrasonic Digital Communication System for a Steel Wall Multipath Channel: Methods and Results
SciTech Connect
Murphy, Timothy L.
2005-12-01
As of the development of this thesis, no commercially available products have been identified for the digital communication of instrumented data across a thick ({approx} 6 n.) steel wall using ultrasound. The specific goal of the current research is to investigate the application of methods for digital communication of instrumented data (i.e., temperature, voltage, etc.) across the wall of a steel pressure vessel. The acoustic transmission of data using ultrasonic transducers prevents the need to breach the wall of such a pressure vessel which could ultimately affect its safety or lifespan, or void the homogeneity of an experiment under test. Actual digital communication paradigms are introduced and implemented for the successful dissemination of data across such a wall utilizing solely an acoustic ultrasonic link. The first, dubbed the ''single-hop'' configuration, can communicate bursts of digital data one-way across the wall using the Differential Binary Phase-Shift Keying (DBPSK) modulation technique as fast as 500 bps. The second, dubbed the ''double-hop'' configuration, transmits a carrier into the vessel, modulates it, and retransmits it externally. Using a pulsed carrier with Pulse Amplitude Modulation (PAM), this technique can communicate digital data as fast as 500 bps. Using a CW carrier, Least Mean-Squared (LMS) adaptive interference suppression, and DBPSK, this method can communicate data as fast as 5 kbps. A third technique, dubbed the ''reflected-power'' configuration, communicates digital data by modulating a pulsed carrier by varying the acoustic impedance at the internal transducer-wall interface. The paradigms of the latter two configurations are believed to be unique. All modulation methods are based on the premise that the wall cannot be breached in any way and can therefore be viably implemented with power delivered wirelessly through the acoustic channel using ultrasound. Methods, results, and considerations for future research are discussed
17. Anterior vaginal wall repair (surgical treatment of urinary incontinence) - slideshow
MedlinePlus
... page: //medlineplus.gov/ency/presentations/100110.htm Anterior vaginal wall repair (surgical treatment of urinary incontinence) - series— ... to slide 4 out of 4 Overview The vaginal opening lies just below the urethral opening, and ...
18. Wall to Wall Optimal Transport
NASA Astrophysics Data System (ADS)
Chini, Gregory P.; Hassanzadeh, Pedram; Doering, Charles R.
2013-11-01
How much heat can be transported between impermeable fixed-temperature walls by incompressible flows with a given amount of kinetic energy or enstrophy? What do the optimal velocity fields look like? We employ variational calculus to address these questions in the context of steady 2D flows. The resulting nonlinear Euler-Lagrange equations are solved numerically, and in some cases analytically, to find the maximum possible Nusselt number Nu as a function of the Péclect number Pe , a measure of the flow's energy or enstrophy. We find that in the fixed-energy problem Nu ~ Pe , while in the fixed-enstrophy problem Nu ~ Pe 10 / 17 . In both cases, the optimal flow consists of an array of convection cells with aspect ratio Γ (Pe) . Interpreting our results in terms of the Rayleigh number Ra for relevant buoyancy-driven problems, we find Nu <= 1 + 0 . 035 Ra and Γ ~ Ra - 1 / 2 for porous medium convection (which occurs with fixed energy), and Nu <= 1 + 0 . 115 Ra 5 / 12 and Γ ~ Ra - 1 / 4 for Rayleigh-Bénard convection (which occurs with fixed enstrophy and for free-slip walls). This work was supported by NSF awards PHY-0855335, DMS-0927587, and PHY-1205219 (CRD) and DMS-0928098 (GPC). Much of this work was completed at the 2012 Geophysical Fluid Dynamics (GFD) Program at Woods Hole Oceanographic Institution.
19. Fundamental string solutions in open string field theories
SciTech Connect
Michishita, Yoji
2006-02-15
In Witten's open cubic bosonic string field theory and Berkovits' superstring field theory we investigate solutions of the equations of motion with appropriate source terms, which correspond to Callan-Maldacena solution in Born-Infeld theory representing fundamental strings ending on the D-branes. The solutions are given in order by order manner, and we show some full order properties in the sense of {alpha}{sup '} expansion. In superstring case we show that the solution is 1/2 BPS in full order.
20. The Berlin Wall: A Simulation for the Social Studies Classroom
ERIC Educational Resources Information Center
Russell, William B., III
2010-01-01
November 9, 2009, marked the twentieth anniversary of the opening of the Berlin Wall. The Wall, a symbol of the Cold War, separated the German people for 28 years (1961-1989), keeping those on the East side isolated. Although the construction and dismantling of the Berlin Wall is a significant part of history, the topic is little covered in the…
1. VIEW TO THE NORTH TOWARD THE WING WALL AND CONCRETESLAB ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
VIEW TO THE NORTH TOWARD THE WING WALL AND CONCRETE-SLAB CHANNEL WALL ON THE WEST SIDE OF THE NORTH END OF THE BRIDGE. NOTE THE SMALL CULVERT OPENING BEHIND SAGEBRUSH NEAR THE END OF THE WING WALL. 37 - Burlington Northern Santa Fe Railroad, Cajon Subdivision, Structure No. 61.5X, between Cajon Summit and Keenbrook, Devore, San Bernardino County, CA
2. On WZ and RR couplings of BPS branes and their all order α‧ corrections in IIB, IIA
NASA Astrophysics Data System (ADS)
Hatefi, Ehsan
2017-03-01
We compute all three and four point couplings of BPS Dp-branes for all different nonzero p-values on the entire world volume and transverse directions. We start finding out all four point function supersymmetric Wess-Zumino (WZ) actions of one closed string Ramond-Ramond (RR) field with two fermions, either with the same (IIB) or different chirality (IIA) as well as their all order α‧ corrections. The closed form of S-matrices of two closed string RR in both IIB, IIA, including their all order α‧ corrections have also been addressed. Our results confirm that, not only the structures of α‧ corrections but also their coefficients of IIB are quite different from their IIA ones. The S-matrix of an RR and two gauge (scalar) fields and their all order corrections in antisymmetric picture of RR have been carried out as well. Various remarks on the restricted Bianchi identities as well as all order α‧ corrections to all different supersymmetric WZ couplings in both type IIA and IIB superstring theory are also released. Lastly, different singularity structures as well as all order contact terms for all non-vanishing traces in type II have also been constructed.
3. Remarks on non-BPS string amplitudes and their all order α' contact interactions in IIB, IIA
NASA Astrophysics Data System (ADS)
Hatefi, Ehsan
2017-03-01
We explore the entire form of S-Matrix elements of a potential C n-1 Ramond-Ramond (RR) form field, a tachyon and two transverse scalar fields on both world volume and transverse directions of type IIB and IIA superstring theories. Apart from < {V}_{C^{-2}}{V}_{φ^0}{V}_{φ^0}{V}_{T^0}\\rangle the other scattering amplitude, namely < {V}_{C^{-1}}{V}_{φ^{-1}}{V}_{φ^0}{V}_{T^0}\\rangle is also revealed. We then start to compare all singularity structures of symmetric and asymmetric analysis, generating all infinite singularity structures as well as all order α' contact interactions on the whole directions. This leads to deriving various new contact terms and several new restricted Bianchi identities in both type IIB and IIA. It is also shown that just some of the new couplings of type IIB (IIA) string theory can be re-verified in an Effective Field Theory (EFT) by pull-back of branes. To construct the rest of S-matrix elements one needs to first derive restricted world volume (or bulk) Bianchi identities and then discover new EFT couplings in both type IIB and IIA. Finally the presence of commutator of scalar fields inside the exponential of Wess-Zumino action for non-BPS branes has been confirmed as well.
4. 12. INTERIOR OF FRONT BEDROOM SHOWING ELECTRICAL WALL HEATER ON ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
12. INTERIOR OF FRONT BEDROOM SHOWING ELECTRICAL WALL HEATER ON BACK WALL, OPEN FIVE-PANELED DOOR TO LIVING ROOM AT PHOTO LEFT, AND OPEN SOLID DOOR TO BATHROOM AT PHOTO CENTER. VIEW TO WEST. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA
5. Correlation between biofilm production, antibiotic susceptibility and exopolysaccharide composition in Burkholderia pseudomallei bpsI, ppk, and rpoS mutant strains.
PubMed
Mongkolrob, Rungrawee; Taweechaisupapong, Suwimol; Tungpradabkul, Sumalee
2015-11-01
Burkholderia pseudomallei is the cause of melioidosis, a fatal tropical infectious disease, which has been reported to have a high rate of recurrence, even when an intensive dose of antibiotics is used. Biofilm formation is believed to be one of the possible causes of relapse because of its ability to increase drug resistance. EPS in biofilms have been reported to be related to the limitation of antibiotic penetration in B. pseudomallei. However, the mechanisms by which biofilms restrict the diffusion of antibiotics remain unclear. The present study presents a correlation between exopolysaccharide production in biofilm matrix and antibiotic resistance in B. pseudomallei using bpsI, ppk, and rpoS mutant strains. CLSM revealed a reduction in exopolysaccharide production and disabled micro-colony formation in B. pseudomallei mutants, which paralleled the antibiotic resistance. Different ratios of carbohydrate contents in the exopolysaccharides of the mutants were detected, although they have the same components, including glucose, galactose, mannose, and rhamnose, with the exception being that no detectable rhamnose peak was observed in the bpsI mutant. These results indicate that the correlation between these phenomena in the B. pseudomallei biofilm at least results from the exopolysaccharide, which may be under the regulation of bpsI, ppk, or rpoS genes.
6. A sensitive single-enzyme assay system using the non-ribosomal peptide synthetase BpsA for measurement of L-glutamine in biological samples
PubMed Central
Brown, Alistair S.; Robins, Katherine J.; Ackerley, David F.
2017-01-01
The ability to rapidly, economically and accurately measure L-glutamine concentrations in biological samples is important for many areas of research, medicine or industry, however there is room for improvement on existing methods. We describe here how the enzyme BpsA, a single-module non-ribosomal peptide synthetase able to convert L-glutamine into the blue pigment indigoidine, can be used to accurately measure L-glutamine in biological samples. Although indigoidine has low solubility in aqueous solutions, meaning direct measurements of indigoidine synthesis do not reliably yield linear standard curves, we demonstrate that resolubilisation of the reaction end-products in DMSO overcomes this issue and that spontaneous reduction to colourless leuco-indigoidine occurs too slowly to interfere with assay accuracy. Our protocol is amenable to a 96-well microtitre format and can be used to measure L-glutamine in common bacterial and mammalian culture media, urine, and deproteinated plasma. We show that active BpsA can be prepared in high yield by expressing it in the apo-form to avoid the toxicity of indigoidine to Escherichia coli host cells, then activating it to the holo-form in cell lysates prior to purification; and that BpsA has a lengthy shelf-life, retaining >95% activity when stored at either −20 °C or 4 °C for 24 weeks. PMID:28139746
7. A sensitive single-enzyme assay system using the non-ribosomal peptide synthetase BpsA for measurement of L-glutamine in biological samples.
PubMed
Brown, Alistair S; Robins, Katherine J; Ackerley, David F
2017-01-31
The ability to rapidly, economically and accurately measure L-glutamine concentrations in biological samples is important for many areas of research, medicine or industry, however there is room for improvement on existing methods. We describe here how the enzyme BpsA, a single-module non-ribosomal peptide synthetase able to convert L-glutamine into the blue pigment indigoidine, can be used to accurately measure L-glutamine in biological samples. Although indigoidine has low solubility in aqueous solutions, meaning direct measurements of indigoidine synthesis do not reliably yield linear standard curves, we demonstrate that resolubilisation of the reaction end-products in DMSO overcomes this issue and that spontaneous reduction to colourless leuco-indigoidine occurs too slowly to interfere with assay accuracy. Our protocol is amenable to a 96-well microtitre format and can be used to measure L-glutamine in common bacterial and mammalian culture media, urine, and deproteinated plasma. We show that active BpsA can be prepared in high yield by expressing it in the apo-form to avoid the toxicity of indigoidine to Escherichia coli host cells, then activating it to the holo-form in cell lysates prior to purification; and that BpsA has a lengthy shelf-life, retaining >95% activity when stored at either -20 °C or 4 °C for 24 weeks.
8. Indirect localization of a magnetic domain wall mediated by quasi walls.
PubMed
Lacour, D; Montaigne, F; Rougemaille, N; Belkhou, R; Raabe, J; Hehn, M
2015-05-26
The manipulation of magnetic domain walls in thin films and nanostructures opens new opportunities for fundamental and applied research. But controlling reliably the position of a moving domain wall still remains challenging. So far, most of the studies aimed at understanding the physics of pinning and depinning processes in the magnetic layer in which the wall moves (active layer). In these studies, the role of other magnetic layers in the stack has been often ignored. Here, we report an indirect localization process of 180° domain walls that occurs in magnetic tunnel junctions, commonly used in spintronics. Combining Scanning Transmission X-Ray Microscopy and micromagnetic simulations, magnetic configurations in both layers are resolved. When nucleating a 180° domain wall in the active layer, a quasi wall is created in the reference layer, atop the wall. The wall and its quasi wall must then be moved or positioned together, as a unique object. As a mutual effect, a localized change of the magnetic properties in the reference layer induces a localized quasi wall in the active layer. The two types of quasi walls are shown to be responsible for an indirect localization process of the 180° domain wall in the active layer.
9. Periodicals Price Survey 2008: Embracing Openness
ERIC Educational Resources Information Center
Van Orsdel, Lee C.; Born, Kathleen
2008-01-01
Evidence for open access as an emergent, global state of mind is everywhere. The "New York Times" went "open" last September, and the "Wall Street Journal" is slated to follow. Increasingly, scholarly communities are breaking with tradition and calling for the open sharing of research, software, and data. Amongst these global initiatives is the…
10. Domain walls riding the wave.
SciTech Connect
Karapetrov, G.; Novosad, V.; Materials Science Division
2010-11-01
Recent years have witnessed a rapid proliferation of electronic gadgets around the world. These devices are used for both communication and entertainment, and it is a fact that they account for a growing portion of household energy consumption and overall world consumption of electricity. Increasing the energy efficiency of these devices could have a far greater and immediate impact than a gradual switch to renewable energy sources. The advances in the area of spintronics are therefore very important, as gadgets are mostly comprised of memory and logic elements. Recent developments in controlled manipulation of magnetic domains in ferromagnet nanostructures have opened opportunities for novel device architectures. This new class of memories and logic gates could soon power millions of consumer electronic devices. The attractiveness of using domain-wall motion in electronics is due to its inherent reliability (no mechanical moving parts), scalability (3D scalable architectures such as in racetrack memory), and nonvolatility (retains information in the absence of power). The remaining obstacles in widespread use of 'racetrack-type' elements are the speed and the energy dissipation during the manipulation of domain walls. In their recent contribution to Physical Review Letters, Oleg Tretiakov, Yang Liu, and Artem Abanov from Texas A&M University in College Station, provide a theoretical description of domain-wall motion in nanoscale ferromagnets due to the spin-polarized currents. They find exact conditions for time-dependent resonant domain-wall movement, which could speed up the motion of domain walls while minimizing Ohmic losses. Movement of domain walls in ferromagnetic nanowires can be achieved by application of external magnetic fields or by passing a spin-polarized current through the nanowire itself. On the other hand, the readout of the domain state is done by measuring the resistance of the wire. Therefore, passing current through the ferromagnetic wire is
11. Wall surveyor project report
SciTech Connect
Mullenhoff, D.J.; Johnston, B.C.; Azevedo, S.G.
1996-02-22
A report is made on the demonstration of a first-generation Wall Surveyor that is capable of surveying the interior and thickness of a stone, brick, or cement wall. LLNLs Micropower Impulse Radar is used, based on emitting and detecting very low amplitude and short microwave impulses (MIR rangefinder). Six test walls were used. While the demonstrator MIR Wall Surveyor is not fieldable yet, it has successfully scanned the test walls and produced real-time images identifying the walls. It is planned to optimize and package the evaluation wall surveyor into a hand held unit.
12. If walls could talk
NASA Technical Reports Server (NTRS)
Braam, J.; McIntire, L. V. (Principal Investigator)
1999-01-01
The plant cell wall is very complex, both in structure and function. The wall components and the mechanical properties of the wall have been implicated in conveying information that is important for morphogenesis. Proteoglycans, fragments of polysaccharides and the structural integrity of the wall may relay signals that influence cellular differentiation and growth control. Furthering our knowledge of cell wall structure and function is likely to have a profound impact on our understanding of how plant cells communicate with the extracellular environment.
13. The Stability of Fake Flat Domain Walls on Kähler Manifold
NASA Astrophysics Data System (ADS)
Akbar, F. T.; Wijaya, R. N.; Gunara, B. E.
2016-08-01
In this paper, we study the stability of flat fake domain walls solution of fake N = 1 supergravity in d + 1 dimensions with Kahler surface as the sigma model. We start with Lagrangian for N = 1 fake supergravity which is coupling between gravity and complex scalar in d + 1 dimensions with scalar potential turned on. Then, as in supergravity theory, we demand that the scalar fields span the Kahler manifold. The equations of motion for fields can be reduced into first order equations by defining the superpotential and the resulting equations are called the projection equation and the fake BPS equation. Finally, we discuss about the stability of flat fake domain walls by investigating the critical points of the superpotential and the scalar potential.
14. Open Content in Open Context
ERIC Educational Resources Information Center
Kansa, Sarah Whitcher; Kansa, Eric C.
2007-01-01
This article presents the challenges and rewards of sharing research content through a discussion of Open Context, a new open access data publication system for field sciences and museum collections. Open Context is the first data repository of its kind, allowing self-publication of research data, community commentary through tagging, and clear…
15. Shear wall ultimate drift limits
SciTech Connect
Duffey, T.A.; Goldman, A.; Farrar, C.R.
1994-04-01
Drift limits for reinforced-concrete shear walls are investigated by reviewing the open literature for appropriate experimental data. Drift values at ultimate are determined for walls with aspect ratios ranging up to a maximum of 3.53 and undergoing different types of lateral loading (cyclic static, monotonic static, and dynamic). Based on the geometry of actual nuclear power plant structures exclusive of containments and concerns regarding their response during seismic (i.e.,cyclic) loading, data are obtained from pertinent references for which the wall aspect ratio is less than or equal to approximately 1, and for which testing is cyclic in nature (typically displacement controlled). In particular, lateral deflections at ultimate load, and at points in the softening region beyond ultimate for which the load has dropped to 90, 80, 70, 60, and 50 percent of its ultimate value, are obtained and converted to drift information. The statistical nature of the data is also investigated. These data are shown to be lognormally distributed, and an analysis of variance is performed. The use of statistics to estimate Probability of Failure for a shear wall structure is illustrated.
16. A prospective, controlled evaluation of the abdominal reapproximation anchor abdominal wall closure system in combination with VAC therapy compared with VAC alone in the management of an open abdomen.
PubMed
Long, Kristin L; Hamilton, David A; Davenport, Daniel L; Bernard, Andrew C; Kearney, Paul A; Chang, Phillip K
2014-06-01
Dramatic increases in damage control and decompressive laparotomies and a significant increase in patients with open abdominal cavities have resulted in numerous techniques to facilitate fascial closure. We hypothesized addition of the abdominal reapproximation anchor system (ABRA) to the KCI Abdominal Wound Vac™ (VAC) or KCI ABThera™ would increase successful primary closure rates and reduce operative costs. Fourteen patients with open abdomens were prospectively randomized into a control group using VAC alone (control) or a study group using VAC plus ABRA (VAC-ABRA). All patients underwent regular VAC changes; patients receiving VAC-ABRA also underwent concomitant daily elastomer adjustment of the ABRA system. Primary end points included abdominal closure, number of operating room (OR) visits, and OR time use. Eight patients were included in the VAC-ABRA group and six patients in the control group. Primary closure rates between groups were not statistically different; however, the number of trips to the OR and OR time use were different. Despite higher Acute Physiology and Chronic Health Evaluation II scores, larger starting wound size, and higher rates of abdominal compartment syndrome, closure rates in the VAC-ABRA group were similar to VAC alone. Importantly, however, fewer OR trips and less OR time were required for the VAC-ABRA group.
17. Open Access
ERIC Educational Resources Information Center
Suber, Peter
2012-01-01
The Internet lets us share perfect copies of our work with a worldwide audience at virtually no cost. We take advantage of this revolutionary opportunity when we make our work "open access": digital, online, free of charge, and free of most copyright and licensing restrictions. Open access is made possible by the Internet and copyright-holder…
18. The Lamportian cell wall
SciTech Connect
Keiliszewski, M.; Lamport, D. )
1991-05-01
The Lamportian Warp-Weft hypothesis suggests a cellulose-extensin interpenetrating network where extensin mechanically couples the load-bearing cellulose microfibrils in a wall matrix that is best described as a microcomposite. This model is based on data gathered from the extensin-rich walls of tomato and sycamore cell suspension culture, wherein extensin precursors are insolubilized into the wall by undefined crosslinks. The authors recent work with cell walls isolated from intact tissue as well as walls from suspension cultured cells of the graminaceous monocots maize and rice, the non-graminaceous monocot asparagus, the primitive herbaceous dicot sugar beet, and the gymnosperm Douglas Fir indicate that although extensins are ubiquitous to all plant species examined, they are not the major structural protein component of most walls examined. Amino acid analyses of intact and HF-treated walls shows a major component neither an HRGP, nor directly comparable to the glycine-rich wall proteins such as those associated with seed coat walls or the 67 mole% glycine-rich proteins cloned from petunia and soybean. Clearly, structural wall protein alternatives to extensin exist and any cell wall model must take that into account. If we assume that extracellular matrices are a priori network structures, then new Hypless' structural proteins in the maize cell wall raise questions about the sort of network these proteins create: the kinds of crosslinks involved; how they are formed; and the roles played by the small amounts of HRGPs.
19. Halogenation of microcapsule walls
NASA Technical Reports Server (NTRS)
Davis, T. R.; Schaab, C. K.; Scott, J. C.
1972-01-01
Procedure for halogenation of confining walls of both gelatin and gelatin-phenolic resin capsules is similar to that used for microencapsulation. Ten percent halogen content renders capsule wall nonburning; any higher content enhances flame-retardant properties of selected internal phase material. Halogenation decreases permeability of wall material to encapsulated materials.
20. Side wall cooling for nozzle segments for a gas turbine
DOEpatents
Burdgick, Steven Sebastian
2002-01-01
A nozzle vane segment includes outer and inner band portions with a vane extending therebetween and defining first and second cavities separated by an impingement plate for flowing cooling medium for impingement cooling of nozzle side walls. The side wall of each nozzle segment has an undercut region. The impingement plate has an inturned flange with a plurality of openings. Cooling inserts or receptacles having an open end are received in the openings and the base and side walls of the receptacles have apertures for receiving cooling medium from the first cavity and directing the cooling medium for impingement cooling of the side wall of the nozzle segment and a portion of the nozzle wall.
1. First Wall and Operational Diagnostics
SciTech Connect
Lasnier, C; Allen, S; Boedo, J; Groth, M; Brooks, N; McLean, A; LaBombard, B; Sharpe, J; Skinner, C; Whyte, D; Rudakov, D; West, W; Wong, C
2006-06-19
In this chapter we review numerous diagnostics capable of measurements at or near the first wall, many of which contribute information useful for safe operation of a tokamak. There are sections discussing infrared cameras, visible and VUV cameras, pressure gauges and RGAs, Langmuir probes, thermocouples, and erosion and deposition measurements by insertable probes and quartz microbalance. Also discussed are dust measurements by electrostatic detectors, laser scattering, visible and IR cameras, and manual collection of samples after machine opening. In each case the diagnostic is discussed with a view toward application to a burning plasma machine such as ITER.
2. 13. FRIST FLOOR, SOUTHEAST ROOM, SOUTHWEST WALL, HEARTH WITH KETTLES ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
13. FRIST FLOOR, SOUTHEAST ROOM, SOUTHWEST WALL, HEARTH WITH KETTLES USED FOR RENDERING LARD (LEFT) AND MAKING APPLE BUTTER (RIGHT) WITH SCALE - Open Gate Farm, House, Ridge Road, 1 mile East of Elephant Road, Perkasie, Bucks County, PA
3. 12. FRIST FLOOR, SOUTHEAST ROOM, SOUTHWEST WALL, HEARTH WITH KETTLES ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
12. FRIST FLOOR, SOUTHEAST ROOM, SOUTHWEST WALL, HEARTH WITH KETTLES USED FOR RENDERING LARD (LEFT) AND MAKING APPLE BUTTER (RIGHT) - Open Gate Farm, House, Ridge Road, 1 mile East of Elephant Road, Perkasie, Bucks County, PA
4. 3. Ice Plant interior, west section, looking north. Crib wall ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
3. Ice Plant interior, west section, looking north. Crib wall of stacked 4' X 6' 's in foreground. Opening leads to refrigeration equipment area. Freezer room to the rear. - Curtis Wharf, Ice Plant, O & Second Streets, Anacortes, Skagit County, WA
5. 16. INTERIOR OF ROOM 105 LOOKING TOWARD SOUTHEAST WALL. EXPOSED ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
16. INTERIOR OF ROOM 105 LOOKING TOWARD SOUTHEAST WALL. EXPOSED POST EXISTS IN MIDDLE OF ROOM. A SMALL OPENING HAS BEEN CUT INTO THE UPPER PORTION OF THE SOUTHEAST WALL THROUGH TO THE ADJOINING ROOM (106). GYPSUM BOARD ON WALLS WITH WOOD TRIM, FLUORESCENT LIGHTING, AND VINYL COMPOSITION TILE ON FLOORS ARE ALL LATER ADDITIONS. - Presidio of San Francisco, Cavalry Stables, Cowles Street, between Lincoln Boulevard & McDowell Street, San Francisco, San Francisco County, CA
6. Fluidized wall for protecting fusion chamber walls
DOEpatents
Maniscalco, James A.; Meier, Wayne R.
1982-01-01
Apparatus for protecting the inner wall of a fusion chamber from microexplosion debris, x-rays, neutrons, etc. produced by deuterium-tritium (DT) targets imploded within the fusion chamber. The apparatus utilizes a fluidized wall similar to a waterfall comprising liquid lithium or solid pellets of lithium-ceramic, the waterfall forming a blanket to prevent damage of the structural materials of the chamber.
7. Wall contraction in Bloch wall films.
NASA Technical Reports Server (NTRS)
Bartran, D. S.; Bourne, H. C., Jr.
1972-01-01
The phenomenon of wall contraction characterized by a peak in the velocity-field relationship and a region of negative differential mobility is observed in uniaxial magnetic thin films of various magnetic properties by careful interrupted-pulse experiments. The observed results agree quite well with the theory for bulk samples when the extensive flux closure of thin film walls is accounted for by a suitable empirical scaling factor.
8. Wall of fundamental constants
SciTech Connect
Olive, Keith A.; Peloso, Marco; Uzan, Jean-Philippe
2011-02-15
We consider the signatures of a domain wall produced in the spontaneous symmetry breaking involving a dilatonlike scalar field coupled to electromagnetism. Domains on either side of the wall exhibit slight differences in their respective values of the fine-structure constant, {alpha}. If such a wall is present within our Hubble volume, absorption spectra at large redshifts may or may not provide a variation in {alpha} relative to the terrestrial value, depending on our relative position with respect to the wall. This wall could resolve the contradiction between claims of a variation of {alpha} based on Keck/Hires data and of the constancy of {alpha} based on Very Large Telescope data. We derive the properties of the wall and the parameters of the underlying microscopic model required to reproduce the possible spatial variation of {alpha}. We discuss the constraints on the existence of the low-energy domain wall and describe its observational implications concerning the variation of the fundamental constants.
9. Cleopatra's Bedroom oblique with picture tube wall along walkway. Structure ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
Cleopatra's Bedroom oblique with picture tube wall along walkway. Structure is made solely of amber colored bottles. Roof supported by telephone poles. Areas of bottle wall above window opening collapsed in the 1994 Northridge earthquake. Camera facing northeast. - Grandma Prisbrey's Bottle Village, 4595 Cochran Street, Simi Valley, Ventura County, CA
10. INTERIOR VIEW, WEST WALL OF NORTHWEST ATTIC CHAMBER. THIS SPACIOUS ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
INTERIOR VIEW, WEST WALL OF NORTHWEST ATTIC CHAMBER. THIS SPACIOUS ROOM INCLUDED A ROOF MONITOR FOR LIGHT AND VENTILATION AND A FIREPLACE FOR HEAT. THE WALL OPENING AND DOOR ON EITHER SIDE OF THE FIREPLACE GIVE ONTO A LARGE UNFINISHED SPACE LOCATED OVER THE HOUSES WEST WING - The Woodlands, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA
11. 65. INTERIOR OF 1902 GENERATOR HOUSE. BASEMENT WALL OF 1901 ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
65. INTERIOR OF 1902 GENERATOR HOUSE. BASEMENT WALL OF 1901 STEAM ENGINE HOUSE VISIBLE AT REAR. BASEMENT WALL OF 1873 WING AT RIGHT. OPENINGS MADE FOR MECHANICALLY TRANSMITTING POWER FROM STEAM ENGINES TO GENERATORS HAVE BEEN BRICKED UP. - Boston Manufacturing Company, 144-190 Moody Street, Waltham, Middlesex County, MA
12. 7. Detail view of mill wall ruins looking E showing ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
7. Detail view of mill wall ruins looking E showing arched openings for Jamaican Train and archeological excavations at base of wall. - Hacienda Azucarera La Esperanza, Mill (Ruins), 2.65 miles North of PR Route 2 Bridge Over Manati River, Manati, Manati Municipio, PR
13. Beyond Walls: A Strategic Plan for James White Library.
ERIC Educational Resources Information Center
Andrews Univ., Berrien Springs, MI. James White Library.
The strategic plan for the James White Library of Andrews University uses the phrase "beyond walls," rather than the catchphrase "library without walls," to acknowledge that printed matter is here to stay but that the paradigm in which it operates is open to innovation and exploration. The fundamental changes taking place in…
14. Liquid Wall Chambers
SciTech Connect
Meier, W R
2011-02-24
The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.
15. Metallic Wall Hall Thrusters
NASA Technical Reports Server (NTRS)
Goebel, Dan Michael (Inventor); Hofer, Richard Robert (Inventor); Mikellides, Ioannis G. (Inventor)
2016-01-01
A Hall thruster apparatus having walls constructed from a conductive material, such as graphite, and having magnetic shielding of the walls from the ionized plasma has been demonstrated to operate with nearly the same efficiency as a conventional non-magnetically shielded design using insulators as wall components. The new design is believed to provide the potential of higher power and uniform operation over the operating life of a thruster device.
16. Individual and mixture endocrine activity of BPS and BPC using in vitro estrogenic/anti-androgenic transcriptional activation assays and the in vivo uterotrophic assay- RAP 2.2-SSWR
EPA Science Inventory
Bisphenol A (BPA) is gradually being phased out of many consumer products and processes leading to potential increases in human and environmental exposures to relatively understudied replacement compounds, including Bisphenol S (BPS) and Bisphenol C (BPC).Research from our lab ha...
17. 2012/14 Beginning Postsecondary Students Longitudinal Study: (BPS:12/14). Supporting Statement Part A. Request for OMB Review. OMB #1850-0631 v.8. Revised May 28, 2014
ERIC Educational Resources Information Center
National Center for Education Statistics, 2014
2014-01-01
The National Center for Education Statistics (NCES), within the U.S. Department of Education (ED), Institute of Education Sciences, is requesting clearance for data collection materials and procedures for the full-scale collection of the 2012/14 Beginning Postsecondary Students Longitudinal Study (BPS:12/14) first follow-up, including the student…
18. Open Education and the Open Science Economy
ERIC Educational Resources Information Center
Peters, Michael A.
2009-01-01
Openness as a complex code word for a variety of digital trends and movements has emerged as an alternative mode of "social production" based on the growing and overlapping complexities of open source, open access, open archiving, open publishing, and open science. This paper argues that the openness movement with its reinforcing structure of…
19. Enhancement of wall jet transport properties
DOEpatents
Claunch, S.D.; Farrington, R.B.
1997-02-04
By enhancing the natural instabilities in the boundary layer and in the free shear layer of a wall jet, the boundary is minimized thereby increasing the transport of heat and mass. Enhancing the natural instabilities is accomplished by pulsing the flow of air that creates the wall jet. Such pulsing of the flow of air can be accomplished by sequentially occluding and opening a duct that confines and directs the flow of air, such as by rotating a disk on an axis transverse to the flow of air in the duct. 17 figs.
20. Enhancement of wall jet transport properties
DOEpatents
Claunch, Scott D.; Farrington, Robert B.
1997-01-01
By enhancing the natural instabilities in the boundary layer and in the free shear layer of a wall jet, the boundary is minimized thereby increasing the transport of heat and mass. Enhancing the natural instabilities is accomplished by pulsing the flow of air that creates the wall jet. Such pulsing of the flow of air can be accomplished by sequentially occluding and opening a duct that confines and directs the flow of air, such as by rotating a disk on an axis transverse to the flow of air in the duct.
1. Opening remarks
SciTech Connect
Hildebrand, S.G.
1994-09-01
Included in this paper are the opening remarks of S.G. Hildebrand, from Environmental Science Division, ORNL, to a conference on water resources and water resource issues. Wetlands are the focus of this talk, with an emphasis on conservation and land use to conserve wetland functions and values.
ERIC Educational Resources Information Center
Baran, Annette; And Others
1976-01-01
Adult adoptees are increasingly challenging the practice of sealing their birth records. The authors examine the historical roots of adoptive practices in this country and suggest that the time has come for open adoption to gain acceptance as an alternative. (Author)
3. INTERIOR DETAIL, SOUTHEAST CABINET NORTH WALL. THE DOORS TO THE ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
INTERIOR DETAIL, SOUTHEAST CABINET NORTH WALL. THE DOORS TO THE LEFT OF THE CHIMNEY MASS OPEN ONTO CLOSETS. ON THE RIGHT, THERE ARE TWO CLOSETS WITH JIB DOORS WITHIN THE CHIMNEY MASS. THE OPEN DOOR CONNECTS WITH THE DRAWING ROOM - The Woodlands, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA
4. 11. INTERIOR OF LIVING ROOM SHOWING BACK WALL ELECTRICAL HEATER, ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
11. INTERIOR OF LIVING ROOM SHOWING BACK WALL ELECTRICAL HEATER, OPEN FIVE-PANELED DOOR TO BACK BEDROOM AT PHOTO RIGHT, AND OPEN DOOR TO KITCHEN AT PHOTO CENTER. VIEW TO NORTHWEST. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA
5. Domain wall filters
SciTech Connect
Baer, Oliver; Narayanan, Rajamani; Neuberger, Herbert; Witzel, Oliver
2007-03-15
We propose using the extra dimension separating the domain walls carrying lattice quarks of opposite handedness to gradually filter out the ultraviolet fluctuations of the gauge fields that are felt by the fermionic excitations living in the bulk. This generalization of the homogeneous domain wall construction has some theoretical features that seem nontrivial.
6. Wall Finishes; Carpentry: 901895.
ERIC Educational Resources Information Center
Dade County Public Schools, Miami, FL.
The course outline is designed to provide instruction in selecting, preparing, and installing wall finishing materials. Prerequisites for the course include mastery of building construction plans, foundations and walls, and basic mathematics. Intended for use in grades 11 and 12, the course contains five blocks of study totaling 135 hours of…
7. Thin Wall Iron Castings
SciTech Connect
J.F. Cuttino; D.M. Stefanescu; T.S. Piwonka
2001-10-31
Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.
8. Interactive Word Walls
ERIC Educational Resources Information Center
Jackson, Julie; Narvaez, Rose
2013-01-01
It is common to see word walls displaying the vocabulary that students have learned in class. Word walls serve as visual scaffolds and are a classroom strategy used to reinforce reading and language arts instruction. Research shows a strong relationship between student word knowledge and academic achievement (Stahl and Fairbanks 1986). As a…
9. 'Stucco' Walls-2
NASA Technical Reports Server (NTRS)
2004-01-01
This image, taken by the microscopic imager, an instrument located on the Mars Exploration Rover Opportunity 's instrument deployment device, or 'arm,' shows the partial 'clodding' or cementation of the sand-sized grains within the trench wall. The area in this image measures approximately 3 centimeters (1.2 inches) across and makes up half of the projected 'Stucco Walls' image.
10. Ferric ions accumulate in the walls of metabolically inactivating Saccharomyces cerevisiae cells and are reductively mobilized during reactivation.
PubMed
Wofford, Joshua D; Park, Jinkyu; McCormick, Sean P; Chakrabarti, Mrinmoy; Lindahl, Paul A
2016-07-13
Mössbauer and EPR spectra of fermenting yeast cells before and after cell wall (CW) digestion revealed that CWs accumulated iron as cells transitioned from exponential to post-exponential growth. Most CW iron was mononuclear nonheme high-spin (NHHS) Fe(III), some was diamagnetic and some was superparamagnetic. A significant portion of CW Fe was removable by EDTA. Simulations using an ordinary-differential-equations-based model suggested that cells accumulate Fe as they become metabolically inactive. When dormant Fe-loaded cells were metabolically reactivated in Fe-deficient bathophenanthroline disulfonate (BPS)-treated medium, they grew using Fe that had been mobilized from their CWs AND using trace amounts of Fe in the Fe-deficient medium. When grown in Fe-deficient medium, Fe-starved cells contained the lowest cellular Fe concentrations reported for a eukaryotic cell. During metabolic reactivation of Fe-loaded dormant cells, Fe(III) ions in the CWs of these cells were mobilized by reduction to Fe(II), followed by release from the CW and reimport into the cell. BPS short-circuited this process by chelating mobilized and released Fe(II) ions before reimport; the resulting Fe(II)(BPS)3 complex adsorbed on the cell surface. NHHS Fe(II) ions appeared transiently during mobilization, suggesting that these ions were intermediates in this process. In the presence of chelators and at high pH, metabolically inactive cells leached CW Fe; this phenomenon probably differs from metabolic mobilization. The iron regulon, as reported by Fet3p levels, was not expressed during post-exponential conditions; Fet3p was maximally expressed in exponentially growing cells. Decreased expression of the iron regulon and metabolic decline combine to promote CW Fe accumulation.
11. 22. SIDE WALL CONSTRUCTION, NORTH TRAINING WALL, LOOKING WEST FROM ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
22. SIDE WALL CONSTRUCTION, NORTH TRAINING WALL, LOOKING WEST FROM THE SAME POINT AS VIEW NO. 21. - Oakland Harbor Training Walls, Mouth of Federal Channel to Inner Harbor, Oakland, Alameda County, CA
12. Opening education.
PubMed
Smith, Marshall S
2009-01-02
Spurred by the publication of Massachusetts Institute of Technology OpenCourseWare in 2002, the open educational resources (OER) movement, which has rapidly expanded and captured the imagination and energy of millions of creators and users throughout the world, now faces many opportunities and substantial challenges as it moves to become an integral part of the world's educational environment. The confluence of the Web and a spirit of sharing intellectual property have fueled a worldwide movement to make knowledge and education materials open to all for use. OER are content (courses, books, lesson plans, articles, etc.), tools (virtual laboratories, simulations, and games), and software that support learning and educational practice. OER are free on the Web, and most have licenses that allow copyright holders to retain ownership while providing specified rights for use in original and modified forms. At the least, OER have helped to level the distribution of knowledge across the world. A second promise of OER is to help transform educational practices. This article explores the history of and promises and challenges for OER.
13. Hollow porous-wall glass microspheres for hydrogen storage
DOEpatents
Heung, Leung K.; Schumacher, Ray F.; Wicks, George G.
2010-02-23
A porous wall hollow glass microsphere is provided having a diameter range of between 1 to 200 microns, a density of between 1.0 to 2.0 gm/cc, a porous-wall structure having wall openings defining an average pore size of between 10 to 1000 angstroms, and which contains therein a hydrogen storage material. The porous-wall structure facilitates the introduction of a hydrogen storage material into the interior of the porous wall hollow glass microsphere. In this manner, the resulting hollow glass microsphere can provide a membrane for the selective transport of hydrogen through the porous walls of the microsphere, the small pore size preventing gaseous or liquid contaminants from entering the interior of the hollow glass microsphere.
14. MIR wall surveyor
SciTech Connect
Lehman, S K
1998-08-01
This report addresses the problem of determining the layer thickness of a wall probed with a monostatic, hand-held implementation of Lawrence Livermore National Laboratory's Micropower Impulse Radar (MIR). Our goal is to locate the layers of the wall, and measure its overall thickness. The physical constraints require the device to be held fixed or swept rapidly over the wall. Thus an insufficient amount of backscattered data are collected to use diffraction tomographic [3] techniques to form images. The problem is therefore one of determining the wall layers from a set of time series reflection data. We develop two channel signal processing algorithms to determine the location of the layers of a wall, using as inputs the time series returned from the wall and the incident pulse. We study the problem using a finite difference time domain (FDTD) computer code to simulate the electromagnetic propagation within and scattering from a wall probed with five pulses. We use the results to develop and test signal processing procedures for locating the individual layers. We study two classes of algorithms: a deconvolution approach to determine a layered impulse response, and a correlation approach. After testing the algorithms on the FDTD results, we down-select to a suitable method.
15. Moving wall, continuous flow electronphoresis apparatus
NASA Technical Reports Server (NTRS)
Rhodes, Percy H. (Inventor); Snyder, Robert S. (Inventor)
1988-01-01
This invention relates generally to electrophoresis devices and more particularly to a moving wall, continuous flow device in which an electrophoresis chamber is angularly positionable with respect to the direction of moving belt walls. A frame with an electrophoresis chamber is rotatably supported between two synchronously driven belt walls. This allows the chamber to be angularly positionable with respect to the direction of belt travel, which compensates for electroosmotic flow within the electrophoresis chamber. Injection of a buffer solution via an opening and a homogenous sample stream via another opening is performed at the end of a chamber, and collection of buffer and the fractionated species particles is done by a conventional collection array at an opposite end of the chamber. Belts are driven at a rate which exactly matches the flow of buffer and sample through the chamber, which entrains the buffer to behave as a rigid electrophoretic medium, eliminating flow distortions (Poiseuille effect). Additionally, belt material for each belt is stored at one end of the device and is taken up by drive wheels at an opposite end. The novelty of this invention particularly lies in the electrophoresis chamber being angularly positionable between two moving belt walls in order to compensate for electroosmotic flow. Additionally, new belt material is continuously exposed within the chamber, minimizing flow distortion due to contamination of the belt material by the sample.
16. Double wall vacuum tubing and method of manufacture
DOEpatents
Stahl, Charles R.; Gibson, Michael A.; Knudsen, Christian W.
1989-01-01
An evacuated double wall tubing is shown together with a method for the manufacture of such tubing which includes providing a first pipe of predetermined larger diameter and a second pipe having an O.D. substantially smaller than the I.D. of the first pipe. An evacuation opening is then in the first pipe. The second pipe is inserted inside the first pipe with an annular space therebetween. The pipes are welded together at one end. A stretching tool is secured to the other end of the second pipe after welding. The second pipe is then prestressed mechanically with the stretching tool an amount sufficient to prevent substantial buckling of the second pipe under normal operating conditions of the double wall pipe. The other ends of the first pipe and the prestressed second pipe are welded together, preferably by explosion welding, without the introduction of mechanical spacers between the pipes. The annulus between the pipes is evacuated through the evacuation opening, and the evacuation opening is finally sealed. The first pipe is preferably of steel and the second pipe is preferably of titanium. The pipes may be of a size and wall thickness sufficient for the double wall pipe to be structurally load bearing or may be of a size and wall thickness insufficient for the double wall pipe to be structurally load bearing, and the double wall pipe positioned with a sliding fit inside a third pipe of a load-bearing size.
17. Opening the Dutch Open Telescope
NASA Astrophysics Data System (ADS)
Rutten, R. J.; de Wijn, A. G.; Sütterlin, P.; Bettonvil, F. C. M.; Hammerschlag, R. H.
2002-10-01
We hope to "open the DOT" to the international solar physics community as a facility for high-resolution tomography of the solar atmosphere. Our aim is to do so combining peer-review time allocation with service-mode operation in a "hands-on-telescope" education program bringing students to La Palma to assist in the observing and processing. The largest step needed is considerable speedup of the DOT speckle processing.
18. Open University
ScienceCinema
None
2016-07-12
Michel Pentz est née en Afrique du Sud et venu au Cern en 1957 comme physicien et président de l'associaion du personnel. Il est également fondateur du mouvement Antiapartheid de Genève et a participé à la fondation de l'Open University en Grande-Bretagne. Il nous parle des contextes pédagogiques, culturels et nationaux dans lesquels la méthode peut s'appliquer.
19. [Nursing care wall planning].
PubMed
Moreau, Véronique
2013-01-01
Nursing care wall planners are not a tool for assessing workload, but a means of providing coherence and individualised monitoring of care. Its application is focused not only on team organisation, but also on the patient's needs.
20. Conducting Wall Hall Thrusters
NASA Technical Reports Server (NTRS)
Goebel, Dan M.; Hofer, Richard R.; Mikellides, Ioannis G.; Katz, Ira; Polk, James E.; Dotson, Brandon
2013-01-01
A unique configuration of the magnetic field near the wall of Hall thrusters, called Magnetic Shielding, has recently demonstrated the ability to significantly reduce the erosion of the boron nitride (BN) walls and extend the life of Hall thrusters by orders of magnitude. The ability of magnetic shielding to minimize interactions between the plasma and the discharge chamber walls has for the first time enabled the replacement of insulating walls with conducting materials without loss in thruster performance. The boron nitride rings in the 6 kW H6 Hall thruster were replaced with graphite that self-biased to near the anode potential. The thruster efficiency remained over 60% (within two percent of the baseline BN configuration) with a small decrease in thrust and increase in Isp typical of magnetically shielded Hall thrusters. The graphite wall temperatures decreased significantly compared to both shielded and unshielded BN configurations, leading to the potential for higher power operation. Eliminating ceramic walls makes it simpler and less expensive to fabricate a thruster to survive launch loads, and the graphite discharge chamber radiates more efficiently which increases the power capability of the thruster compared to conventional Hall thruster designs.
1. Closure of the open abdomen.
PubMed
Björck, Martin; D'Amours, Scott K; Hamilton, A E Ricardo
2011-07-01
The open abdomen is a valuable tool in the management of patients with intra-abdominal hypertension and abdominal compartment syndrome. The longer an abdomen is left open, the greater the potential morbidity, however. From the very start, specific measures should be considered to increase the likelihood of definitive closure and prevent the development of visceral adhesions, lateralization, and/or loss of skin and fascia, ileus, fistulae, and malnutrition. Early definitive closure of all abdominal wall layers is the short-term goal of management once the need for the open abdomen has resolved. Several devices and strategies improve the chances for definitive closure. If a frozen abdomen develops, split-thickness skin grafting of a granulating open abdominal wound base is an alternative. Early coverage of the exposed viscera and acceptance of a large abdominal hernia permit earlier reversal of the catabolic state and lower the risk of fistula formation. When a stoma is required, sealing and separation can become problematic. If a fistula develops, a more complex situation prevails, requiring specific techniques to isolate its output and a longer-term strategy to restore intestinal continuity. Planning the closure of an open abdomen is a process that starts on the first day that the abdomen is opened. Multiple factors need to be addressed, optimized, and controlled to achieve the best outcome.
2. 29. Detail view of small triangular openings from opposite side ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
29. Detail view of small triangular openings from opposite side of wall. - Hacienda Azurarera Santa Elena, Sugar Mill Ruins, 1.44 miles North of PR Route 2 Bridge Over Rio De La Plata, Toa Baja, Toa Baja Municipio, PR
3. View of main hoist wire rope drum and brakes, open ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
View of main hoist wire rope drum and brakes, open contact boards are in view at the far right wall - Puget Sound Naval Shipyard, Portal Gantry Crane No. 42, Pier 5, Farragut Avenue, Bremerton, Kitsap County, WA
4. Ultimate Cost of Building Walls.
ERIC Educational Resources Information Center
Grimm, Clayford T.; Gross, James G.
The need for economic analysis of building walls is discussed, and the factors influencing the ultimate cost of exterior walls are studied. The present worth method is used to analyze three types of exterior non-loadbearing panel or curtain walls. Anticipated costs are expressed in terms of their present value per square foot of wall area. The…
5. OpenER, a Dutch Initiative in Open Educational Resources
ERIC Educational Resources Information Center
Schuwer, Robert; Mulder, Fred
2009-01-01
Over the period 2006-2008, the Dutch Open Universiteit Nederland conducted an experiment in which Open Educational Resources (OER) were offered in an effort to bridge the gap between informal and formal learning and to establish a new style of entry portal to higher education with no barriers at all. OpenER received considerable attention both in…
6. 9. INTERIOR OF LIVING ROOM SHOWING OPEN DOORWAY TO KITCHEN ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
9. INTERIOR OF LIVING ROOM SHOWING OPEN DOORWAY TO KITCHEN AT PHOTO LEFT CENTER, AND 6-LIGHT OVER 1-LIGHT SASH WINDOW ON REAR WALL AT PHOTO RIGHT. FIREPLACE ORIGINALLY OCCUPIED SPACE TO THE EXTREME PHOTO RIGHT OF SASH WINDOW ON THE REAR WALL. VIEW TO SOUTH. - Rush Creek Hydroelectric System, Worker Cottage, Rush Creek, June Lake, Mono County, CA
7. 8. INTERIOR OF LIVING ROOM SHOWING OPEN DOORWAY TO KITCHEN, ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
8. INTERIOR OF LIVING ROOM SHOWING OPEN DOORWAY TO KITCHEN, 6-LIGHT OVER 1-LIGHT SASH WINDOWS ON FRONT WALL AT PHOTO LEFT, AND 6-LIGHT OVER 1-LIGHT SASH WINDOW ON BACK WALL AT EXTREME PHOTO RIGHT. VIEW TO EAST. - Rush Creek Hydroelectric System, Worker Cottage, Rush Creek, June Lake, Mono County, CA
8. Interior of southwest vault, opened southwest vault door, closed southeast ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
Interior of southwest vault, opened southwest vault door, closed southeast vault door, and evidence of forced entry in north interior wall. View from west interior wall of southwest vault. Facing east. - Travis Air Force Base, Building No. 925, W Street, Fairfield, Solano County, CA
9. South interior wall, view to the East from near the ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
South interior wall, view to the East from near the center of the building. At present there is open storage above the fluorescent lights. Behind the interior half wall, modern office occupy the area formerly used as a machine shop (See drawing copy NV-35-B-5) - Bureau of Mines Metallurgical Research Laboratory, Original Building, Date Street north of U.S. Highway 93, Boulder City, Clark County, NV
10. Musculoskeletal chest wall pain
PubMed Central
Fam, Adel G.; Smythe, Hugh A.
1985-01-01
The musculoskeletal structures of the thoracic wall and the neck are a relatively common source of chest pain. Pain arising from these structures is often mistaken for angina pectoris, pleurisy or other serious disorders. In this article the clinical features, pathogenesis and management of the various musculoskeletal chest wall disorders are discussed. The more common causes are costochondritis, traumatic muscle pain, trauma to the chest wall, “fibrositis” syndrome, referred pain, psychogenic regional pain syndrome, and arthritis involving articulations of the sternum, ribs and thoracic spine. Careful analysis of the history, physical findings and results of investigation is essential for precise diagnosis and effective treatment. ImagesFig. 3Fig. 4Fig. 5 PMID:4027804
11. Mouse bladder wall injection.
PubMed
Fu, Chi-Ling; Apelo, Charity A; Torres, Baldemar; Thai, Kim H; Hsieh, Michael H
2011-07-12
Mouse bladder wall injection is a useful technique to orthotopically study bladder phenomena, including stem cell, smooth muscle, and cancer biology. Before starting injections, the surgical area must be cleaned with soap and water and antiseptic solution. Surgical equipment must be sterilized before use and between each animal. Each mouse is placed under inhaled isoflurane anesthesia (2-5% for induction, 1-3% for maintenance) and its bladder exposed by making a midline abdominal incision with scissors. If the bladder is full, it is partially decompressed by gentle squeezing between two fingers. The cell suspension of interest is intramurally injected into the wall of the bladder dome using a 29 or 30 gauge needle and 1 cc or smaller syringe. The wound is then closed using wound clips and the mouse allowed to recover on a warming pad. Bladder wall injection is a delicate microsurgical technique that can be mastered with practice.
12. Thermal treatment wall
DOEpatents
Aines, Roger D.; Newmark, Robin L.; Knauss, Kevin G.
2000-01-01
A thermal treatment wall emplaced to perform in-situ destruction of contaminants in groundwater. Thermal destruction of specific contaminants occurs by hydrous pyrolysis/oxidation at temperatures achievable by existing thermal remediation techniques (electrical heating or steam injection) in the presence of oxygen or soil mineral oxidants, such as MnO.sub.2. The thermal treatment wall can be installed in a variety of configurations depending on the specific objectives, and can be used for groundwater cleanup, wherein in-situ destruction of contaminants is carried out rather than extracting contaminated fluids to the surface, where they are to be cleaned. In addition, the thermal treatment wall can be used for both plume interdiction and near-wellhead in-situ groundwater treatment. Thus, this technique can be utilized for a variety of groundwater contamination problems.
13. Axion domain wall baryogenesis
SciTech Connect
Daido, Ryuji; Kitajima, Naoya; Takahashi, Fuminobu
2015-07-28
We propose a new scenario of baryogenesis, in which annihilation of axion domain walls generates a sizable baryon asymmetry. Successful baryogenesis is possible for a wide range of the axion mass and decay constant, m≃10{sup 8}–10{sup 13} GeV and f≃10{sup 13}–10{sup 16} GeV. Baryonic isocurvature perturbations are significantly suppressed in our model, in contrast to various spontaneous baryogenesis scenarios in the slow-roll regime. In particular, the axion domain wall baryogenesis is consistent with high-scale inflation which generates a large tensor-to-scalar ratio within the reach of future CMB B-mode experiments. We also discuss the gravitational waves produced by the domain wall annihilation and its implications for the future gravitational wave experiments.
14. Openness initiative
SciTech Connect
Duncan, S.S.
1995-12-31
Although antinuclear campaigns seem to be effective, public communication and education efforts on low-level radioactive waste have mixed results. Attempts at public information programs on low-level radioactive waste still focus on influencing public opinion. A question then is: {open_quotes}Is it preferable to have a program focus on public education that will empower individuals to make informed decisions rather than trying to influence them in their decisions?{close_quotes} To address this question, a case study with both quantitative and qualitative data will be used. The Ohio Low-Level Radioactive Waste Education Program has a goal to provide people with information they want/need to make their own decisions. The program initiated its efforts by conducting a statewide survey to determine information needed by people and where they turned for that information. This presentation reports data from the survey and then explores the program development process in which programs were designed and presented using the information. Pre and post data from the programs reveal attitude and knowledge shifts.
15. Efficient Photovoltaic Current Generation at Ferroelectric Domain Walls
NASA Astrophysics Data System (ADS)
Seidel, Jan; Fu, Deyi; Yang, Seung-Yeul; Alarcón-Lladó, Esther; Wu, Junqiao; Ramesh, Ramamoorthy; Ager, Joel W., III
2011-09-01
We elucidate the mechanism of a newly observed photovoltaic effect which occurs in ferroelectrics with periodic domain structures. Under sufficiently strong illumination, domain walls function as nanoscale generators of the photovoltaic current. The steps in the electrostatic potential function to accumulate electrons and holes on opposite sides of the walls while locally reducing the concentration of the oppositely charged carriers. As a result, the recombination rate adjacent to the walls is reduced, leading to a net diffusion current. In open circuit, photovoltages for periodically ordered domain walls are additive and voltages much larger than the band gap can be generated. The internal quantum efficiency for individual domain walls can be surprisingly high, approaching 10% for above band-gap photons. Although we have found the effect in BiFeO3 films, it should occur in any system with a similar periodic potential.
16. Use of reinforced soil wall to support steam generator transfer
SciTech Connect
Davie, J.R.; Wang, J.T. ); Gladstone, R.A. )
1991-01-01
Consumers Power Company had the two steam generators at its Palisades Nuclear Plant in Michigan replaced in November 1990. This replacement was accomplished through a 26-foot wide by 28-foot high opening cut into the wall of the containment building, about 45 feet above the original ground surface. Because this ground surface was at an approximately 3-H:1-V slope, leveling was required before replacement in order to provide access for the steam generators and adequate support for the heavy-duty gantry crane system used to transfer the generators. A 25-foot high reinforced soil wall was constructed to achieve the level surface. This paper describes the design and construction of the heavily loaded reinforced soil wall, including ground improvement measures required to obtain adequate wall stability. The performance of the wall under test loading will also be presented and discussed.
17. Magnetic Domain Wall Floating on a Spin Superfluid
NASA Astrophysics Data System (ADS)
Upadhyaya, Pramey; Kim, Se Kwon; Tserkovnyak, Yaroslav
2017-03-01
We theoretically investigate the transfer of angular momentum between a spin superfluid and a domain wall in an exchange coupled easy-axis and easy-plane magnetic insulator system. A domain wall in the easy-axis magnet absorbs spin angular momentum via disrupting the flow of a superfluid spin current in the easy-plane magnet. Focusing on an open geometry, where the spin current is injected electrically via a nonequilibrium spin accumulation, we derive analytical expressions for the resultant superfluid-mediated motion of the domain wall. The analytical results are supported by micromagnetic simulations. The proposed phenomenon extends the regime of magnon-driven domain-wall motion to the case where the magnons are condensed and exhibit superfluidity. Furthermore, by controlling the pinning of the domain wall, we propose a realization of a reconfigurable spin transistor. The long-distance dissipationless character of spin superfluids can thus be exploited for manipulating soliton-based memory and logic devices.
18. Gullies in Crater Wall
NASA Technical Reports Server (NTRS)
2003-01-01
MGS MOC Release No. MOC2-388, 11 June 2003
Many craters and troughs at polar and middle latitudes on Mars have gullies carved in their walls. These gullies may have formed by running water; others have suggested alternative, exotic fluids such as liquid or gaseous carbon dioxide. This view of martian gullies was acquired by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC). The image shows gullies in the wall of an old meteor impact crater near 39.0oS, 200.7oW. Sunlight illuminates the scene from the upper left.
19. Gullied Crater Wall
NASA Technical Reports Server (NTRS)
2003-01-01
MGS MOC Release No. MOC2-371, 25 May 2003
Gullies are common in some regions on middle- and polar-latitude slopes, such as crater walls. This March 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies on the north wall of a crater in the Atlantis Chaos region near 34.3oS, 178.0oW. The gullies might have formed by flow of a fluid--perhaps liquid water--sometime in the geologically recent martian past. Sunlight illuminates the scene from the upper left.
20. Wall mounted combined radiactive-convective electric space heater
SciTech Connect
Meiser, R.; Burkert, J.; Bendel, R.
1987-07-21
A space heating apparatus is described for mounting on a wall surface of a room to be heated, the apparatus comprising: a housing including a substantially flat rear wall adapted for mounting to the wall surface. A front wall adjacent the rear wall, the front wall and the real wall conjointly defining a space between through which the air passes. The front wall has a lower portion extending upwardly from the bottom of the housing a solid uninterrupted mid portion devoid of any openings and a portion extending upwardly; an inlet means at the lower end of the housing admits and directs the air into the space; air outlet means at the upper end of the housing where heated air leaves the space and passes from the housing: a solid, uninterrupted metal plate having a first flat side and a second flat side; an electrically insulating plastic layer formed only on the first flat side of the metal plate; the metal plate being mounted in the space so as to partition the space into two convecting channels and having an upper portion extending above the mid portion of the front wall; the plastic layer and the rear wall conjointly defining one of the convecting channels for communicating with a portion of the air outlet means and for conducting a portion of the incoming air admitted to the space; the second flat side and the front wall with the solid uninterrupted mid portion conjointly defining the other one of the convecting channels; resistance heating means embedded in and throughout the plastic layer for heating the air rising in both of the convecting channels and for radiating heat from the second flat side of the plate; and the remainder of the outlet means being formed in the upper portion of the front wall so as to be disposed laterally of the upper portion of the metal plate.
NASA Astrophysics Data System (ADS)
Crovini, L.
1994-01-01
Ladies and Gentlemen To quote Mr Jean Terrien: "Physics must be one step ahead of metrology". A long-serving Director of the BIPM, he said these words when visiting the IMGC in 1970 as a member of the scientific board of our Institute. At that time it was still an open question whether the IMGC should start research work on the absolute measurement of silicon lattice spacing. Mr Terrien underlined the revolutionary character of x-ray interferometry and, eventually, he caused the balance needle to lean towards the ... right direction. Mr Terrien correctly foresaw that, like Michelson's interferometer of 1880, x-ray interferometry could have a prominent place in today's science and technology. And while, in the first case, after more than a century we can see instruments based on electromagnetic wave interaction within every one's reach in laboratories and, sometimes, in workshops, in the second case, twenty-five years since the first development of an x-ray interferometer we can witness its role in nanometrology. Today and tomorrow we meet to discuss how to go beyond the sixth decimal place in the value of the Avogadro constant. We are aware that the quest for this achievement requires the cooperation of scientists with complementary capabilities. I am sure that the present workshop is a very good opportunity to present and discuss results and to improve and extend existing cooperation. The new adjustment of fundamental constants envisaged by the CODATA Task Group is redoubling scientists' efforts to produce competitive values of NA. The results of the measurements of the silicon lattice spacing in terms of an optical wavelength, which were available for the 1986 adjustment, combined with the determination of silicon molar volume, demonstrate how such an NA determination produces a consistent set of other constants and opens the way to a possible redefinition of the kilogram. We shall see in these two days how far we have progressed along this road. For us at the
2. Fly on the Wall
ERIC Educational Resources Information Center
Berry, Dave; Korpan, Cynthia
2009-01-01
This paper describes the implementation of a peer observation program at the University of Victoria called the Lecture Club. The observers are not interactive during the class--they are the proverbial flies on the wall. The paper identifies the program as self-developmental, discussing the attributes of this learning-to-teach and peer-sharing…
3. A Wall of Faces
ERIC Educational Resources Information Center
Stevens, Lori
2008-01-01
Visitors to the campus of Orland High School (OHS) will never question that they have stepped into a world of the masses: kids, activity, personalities, busyness, and playfulness--a veritable cloud of mild bedlam. The wall of ceramic faces that greets a visitor in the school office is another reminder of the organized chaos that the teachers…
4. A School without Walls.
ERIC Educational Resources Information Center
Venuti, Len Tai
1994-01-01
During the summer, selected students of Hawaiian ancestry who have completed seventh or eighth grade participate in a boarding program with outdoor activities such as pulling taro, star gazing, and camping. The activities eliminate walls of doubt and fear and nurture self-confidence, creativity, personal growth, leadership, and cultural awareness.…
5. The Wall Coverings Challenge
ERIC Educational Resources Information Center
Roman, Harry T.
2012-01-01
Students love nothing better than personalizing their space--desk, bedroom, or even their cars. This article describes a classroom challenge that gives students a chance to let their spirits soar with the invention of a new form of wall treatment. A trip to a big box store might prove to be most helpful for students to visualize their new product…
6. Wall turbulence control
NASA Technical Reports Server (NTRS)
Wilkinson, Stephen P.; Lindemann, A. Margrethe; Beeler, George B.; Mcginley, Catherine B.; Goodman, Wesley L.; Balasubramanian, R.
1986-01-01
A variety of wall turbulence control devices which were experimentally investigated are discussed; these include devices for burst control, alteration of outer flow structures, large eddy substitution, increased heat transfer efficiency, and reduction of wall pressure fluctuations. Control of pre-burst flow was demonstrated with a single, traveling surface depression which is phase-locked to elements of the burst production process. Another approach to wall turbulence control is to interfere with the outer layer coherent structures. A device in the outer part of a boundary layer was shown to suppress turbulence and reduce drag by opposing both the mean and unsteady vorticity in the boundary layer. Large eddy substitution is a method in which streamline curvature is introduced into the boundary layer in the form of streamwise vortices. Riblets, which were already shown to reduce turbulent drag, were also shown to exhibit superior heat transfer characteristics. Heat transfer efficiency as measured by the Reynolds Analogy Factor was shown to be as much as 36 percent greater than a smooth flat plate in a turbulent boundary layer. Large Eddy Break-Up (LEBU) which are also known to reduce turbulent drag were shown to reduce turbulent wall pressure fluctuation.
7. Lateral Abdominal Wall Reconstruction
PubMed Central
Baumann, Donald P.; Butler, Charles E.
2012-01-01
Lateral abdominal wall (LAW) defects can manifest as a flank hernias, myofascial laxity/bulges, or full-thickness defects. These defects are quite different from those in the anterior abdominal wall defects and the complexity and limited surgical options make repairing the LAW a challenge for the reconstructive surgeon. LAW reconstruction requires an understanding of the anatomy, physiologic forces, and the impact of deinnervation injury to design and perform successful reconstructions of hernia, bulge, and full-thickness defects. Reconstructive strategies must be tailored to address the inguinal ligament, retroperitoneum, chest wall, and diaphragm. Operative technique must focus on stabilization of the LAW to nonyielding points of fixation at the anatomic borders of the LAW far beyond the musculofascial borders of the defect itself. Thus, hernias, bulges, and full-thickness defects are approached in a similar fashion. Mesh reinforcement is uniformly required in lateral abdominal wall reconstruction. Inlay mesh placement with overlying myofascial coverage is preferred as a first-line option as is the case in anterior abdominal wall reconstruction. However, interposition bridging repairs are often performed as the surrounding myofascial tissue precludes a dual layered closure. The decision to place bioprosthetic or prosthetic mesh depends on surgeon preference, patient comorbidities, and clinical factors of the repair. Regardless of mesh type, the overlying soft tissue must provide stable cutaneous coverage and obliteration of dead space. In cases where the fasciocutaneous flaps surrounding the defect are inadequate for closure, regional pedicled flaps or free flaps are recruited to achieve stable soft tissue coverage. PMID:23372458
8. Moisture Research - Optimizing Wall Assemblies
SciTech Connect
Arena, Lois; Mantha, Pallavi
2013-05-01
In this project, the Consortium for Advanced Residential Buildings (CARB) team evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls. Wall assemblies evaluated included code minimum walls using spray foam insulation and fiberglass batts, high R-value walls at least 12 in. thick (R-40 and R-60 assemblies), and brick walls with interior insulation.
9. 1. SOUTHEAST REAR WALL AND NORTHEAST SIDE WALL OF CABINS ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
1. SOUTHEAST REAR WALL AND NORTHEAST SIDE WALL OF CABINS FORGEMAN'S HOUSE NO. 1 AT RIGHT - Mount Etna Iron Works, Forgeman's House No. 1, Legislative Route 07020 between junctions of T.R. 461 & 463, Williamsburg, Blair County, PA
10. Typical Window, Interior Wall Paint Sequence, Wall Section, and Foundation ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
Typical Window, Interior Wall Paint Sequence, Wall Section, and Foundation Sections - Civilian Conservation Corps (CCC) Camp NP-5-C, Barracks No. 5, CCC Camp Historic District at Chapin Mesa, Cortez, Montezuma County, CO
11. 4. CONSTRUCTION DETAIL, SW CORNER, SHOWING RETAINING WALL, BRIDGE WALL ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
4. CONSTRUCTION DETAIL, SW CORNER, SHOWING RETAINING WALL, BRIDGE WALL AND EROSION ON ROAD SURFACE. - Bridalveil Fall Bridge No. 3, Spanning Bridalveil Creek on carriage road, Yosemite Village, Mariposa County, CA
12. DETAIL OF CROCKETT BARN WALL CONSTRUCTION, UPPER LEVEL. The wall ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
DETAIL OF CROCKETT BARN WALL CONSTRUCTION, UPPER LEVEL. The wall construction of the Crockett barn includes a layer of diagonal sheathing that is exposed on the interior. - Crockett Farm, Barn, 1056 Fort Casey Road, Coupeville, Island County, WA
13. Interior view of wall detail of southeast wall, view towards ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
Interior view of wall detail of southeast wall, view towards the southeast, without scale - Fort McClellan Ammunition Storage Area, Building No. 4408, Second Avenue (Magazine Road), Anniston, Calhoun County, AL
14. EAST WALL OF CRYSTALLIZER WING TO THE LEFT, END WALL ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
EAST WALL OF CRYSTALLIZER WING TO THE LEFT, END WALL OF CRUSHING MILL IN CENTER. GABLE END OF BOILING HOUSE IN LEFT BACKGROUND. VIEW FROM THE SOUTH - Kekaha Sugar Company, Sugar Mill Building, 8315 Kekaha Road, Kekaha, Kauai County, HI
15. 40. RETAINING WALL CONSTRUCTION SHOWING PORTION OF COMPLETED WALL. BACKFILLING ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
40. RETAINING WALL CONSTRUCTION SHOWING PORTION OF COMPLETED WALL. BACKFILLING BY POWER SHOVEL IN PROGRESS. ZION NP NEGATIVE NO. 1490. PHOTOGRAPHER: PARKER, NO DATE - Zion-Mount Carmel Highway, Springdale, Washington County, UT
16. Open Education Revisited.
ERIC Educational Resources Information Center
Bough, Max, Ed.
1979-01-01
This journal provides 12 brief articles focused on open education. Topics explored include (1) open education and reading, (2) mainstreaming, (3) characteristics of an open teacher, (4) administration of an open concept school, (5) an existential methodology in the language arts, (6) social studies in open education, (7) open education in early…
17. Open Standards, Open Source, and Open Innovation: Harnessing the Benefits of Openness
ERIC Educational Resources Information Center
Committee for Economic Development, 2006
2006-01-01
Digitization of information and the Internet have profoundly expanded the capacity for openness. This report details the benefits of openness in three areas--open standards, open-source software, and open innovation--and examines the major issues in the debate over whether openness should be encouraged or not. The report explains each of these…
18. Wind tunnels with adapted walls for reducing wall interference
NASA Technical Reports Server (NTRS)
Ganzer, U.
1979-01-01
The basic principle of adaptable wind tunnel walls is explained. First results of an investigation carried out at the Aero-Space Institute of Berlin Technical University are presented for two dimensional flexible walls and a NACA 0012 airfoil. With five examples exhibiting very different flow conditions it is demonstrated that it is possible to reduce wall interference and to avoid blockage at transonic speeds by wall adaptation.
NASA Astrophysics Data System (ADS)
2014-12-01
20. Dielectric relaxation and charged domain walls in (K,Na)NbO3-based ferroelectric ceramics
NASA Astrophysics Data System (ADS)
Esin, A. A.; Alikin, D. O.; Turygin, A. P.; Abramov, A. S.; Hreščak, J.; Walker, J.; Rojac, T.; Bencan, A.; Malic, B.; Kholkin, A. L.; Shur, V. Ya.
2017-02-01
The influence of domain walls on the macroscopic properties of ferroelectric materials is a well known phenomenon. Commonly, such "extrinsic" contributions to dielectric permittivity are discussed in terms of domain wall displacements under external electric field. In this work, we report on a possible contribution of charged domain walls to low frequency (10-106 Hz) dielectric permittivity in K1-xNaxNbO3 ferroelectric ceramics. It is shown that the effective dielectric response increases with increasing domain wall density. The effect has been attributed to the Maxwell-Wagner-Sillars relaxation. The obtained results may open up possibilities for domain wall engineering in various ferroelectric materials.
1. 25. NORTH TRAINING WALL, EAST SECTION, SIDE WALL CONSTRUCTION, LOOKING ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
25. NORTH TRAINING WALL, EAST SECTION, SIDE WALL CONSTRUCTION, LOOKING WEST FROM A POINT ABOUT 500 FEET FROM THE MIDDLE HARBOR PARK FISHING PIER. (Panoramic view 1 of 2). - Oakland Harbor Training Walls, Mouth of Federal Channel to Inner Harbor, Oakland, Alameda County, CA
2. High-R Walls for Remodeling. Wall Cavity Moisture Monitoring
SciTech Connect
Wiehagen, J.; Kochkin, V.
2012-12-01
The focus of the study is on the performance of wall systems, and in particular, the moisture characteristics inside the wall cavity and in the wood sheathing. Furthermore, while this research will initially address new home construction, the goal is to address potential moisture issues in wall cavities of existing homes when insulation and air sealing improvements are made.
3. High-R Walls for Remodeling: Wall Cavity Moisture Monitoring
SciTech Connect
Wiehagen, J.; Kochkin, V.
2012-12-01
The focus of the study is on the performance of wall systems, and in particular, the moisture characteristics inside the wall cavity and in the wood sheathing. Furthermore, while this research will initially address new home construction, the goal is to address potential moisture issues in wall cavities of existing homes when insulation and air sealing improvements are made.
4. 16. INTERIOR OF BEDROOM NUMBER TWO SHOWING OPEN PANEL DOOR ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
16. INTERIOR OF BEDROOM NUMBER TWO SHOWING OPEN PANEL DOOR TO WALK-IN CLOSET AT PHOTO CENTER, OPEN PANEL DOOR FROM BEDROOM NUMBER ONE AT EXTREME PHOTO LEFT, AND 6-LIGHT OVER 1-LIGHT SASH WINDOW ON NORTH WALL AT PHOTO RIGHT. VIEW TO WEST. - Rush Creek Hydroelectric System, Worker Cottage, Rush Creek, June Lake, Mono County, CA
5. 8. INTERIOR OF LIVING ROOM SHOWING OPEN DOORWAY TO KITCHEN ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
8. INTERIOR OF LIVING ROOM SHOWING OPEN DOORWAY TO KITCHEN AT PHOTO RIGHT, 6-LIGHT OVER 1-LIGHT SASH WINDOWS ON FRONT (EAST) WALL AT PHOTO CENTER. ENTRY ROOM AND OPEN 1-LIGHT FRONT DOOR AT EXTREME PHOTO LEFT. VIEW TO SOUTHEAST. - Rush Creek Hydroelectric System, Worker Cottage, Rush Creek, June Lake, Mono County, CA
6. INTERIOR VIEW OF THE NORTH ROOM. DOOR OPENING LEADS TO ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
INTERIOR VIEW OF THE NORTH ROOM. DOOR OPENING LEADS TO STAIRWAY UP TO THE ABOVE-GROUND PORTION. NOTE THE SQUARE TUNNEL OPENING AT CENTER, AND THE CONDUIT SLEEVES AND PIPE PROTRUDING FROM THE NORTH WALL AT LEFT. VIEW FACING NORTHEAST - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, Battery Command Center, Ford Island, Pearl City, Honolulu County, HI
7. DIELECTRIC WALL ACCELERATOR TECHNOLOGY
SciTech Connect
Sampayan, S; Caporaso, G; Chen, Y; Harris, J; Hawkins, S; Holmes, C; Nelson, S; Poole, B; Rhodes, M; Sanders, D; Sullivan, J; Wang, L; Watson, J
2007-10-18
The dielectric wall accelerator (DWA) is a compact pulsed power device where the pulse forming lines, switching, and vacuum wall are integrated into a single compact geometry. For this effort, we initiated a extensive compact pulsed power development program and have pursued the study of switching (gas, oil, laser induced surface flashover and photoconductive), dielectrics (ceramics and nanoparticle composites), pulse forming line topologies (asymmetric and symmetric Blumleins and zero integral pulse forming lines), and multilayered vacuum insulator (HGI) technology. Finally, we fabricated an accelerator cell for test on ETAII (a 5.5 MeV, 2 kA, 70 ns pulsewidth electron beam accelerator). We review our past results and report on the progress of accelerator cell testing.
8. The Dielectric Wall Accelerator
SciTech Connect
Caporaso, George J.; Chen, Yu-Jiuan; Sampayan, Stephen E.
2009-01-01
The Dielectric Wall Accelerator (DWA), a class of induction accelerators, employs a novel insulating beam tube to impress a longitudinal electric field on a bunch of charged particles. The surface flashover characteristics of this tube may permit the attainment of accelerating gradients on the order of 100 MV/m for accelerating pulses on the order of a nanosecond in duration. A virtual traveling wave of excitation along the tube is produced at any desired speed by controlling the timing of pulse generating modules that supply a tangential electric field to the tube wall. Because of the ability to control the speed of this virtual wave, the accelerator is capable of handling any charge to mass ratio particle; hence it can be used for electrons, protons and any ion. The accelerator architectures, key technologies and development challenges will be described.
9. Curtain Wall Creates Ventilation Channel
NASA Technical Reports Server (NTRS)
Lewis, E. V.
1985-01-01
Curtain-wall structure proposed for removing methane and airborne coal dust from hydrojet-jaw mining machines. Channel between curtain wall and mine wall forms closed exhaust passage. Through it, gas and dust continuously removed so high concentrations of these explosive materials not build up.
10. Molded Concrete Center Mine Wall
NASA Technical Reports Server (NTRS)
Lewis, E. V.
1987-01-01
Proposed semiautomatic system forms concrete-foam wall along middle of coal-mine passage. Wall helps support roof and divides passage into two conduits needed for ventilation of coal face. Mobile mold and concrete-foam generator form sections of wall in place.
11. Left ventricular wall stress compendium.
PubMed
Zhong, L; Ghista, D N; Tan, R S
2012-01-01
Left ventricular (LV) wall stress has intrigued scientists and cardiologists since the time of Lame and Laplace in 1800s. The left ventricle is an intriguing organ structure, whose intrinsic design enables it to fill and contract. The development of wall stress is intriguing to cardiologists and biomedical engineers. The role of left ventricle wall stress in cardiac perfusion and pumping as well as in cardiac pathophysiology is a relatively unexplored phenomenon. But even for us to assess this role, we first need accurate determination of in vivo wall stress. However, at this point, 150 years after Lame estimated left ventricle wall stress using the elasticity theory, we are still in the exploratory stage of (i) developing left ventricle models that properly represent left ventricle anatomy and physiology and (ii) obtaining data on left ventricle dynamics. In this paper, we are responding to the need for a comprehensive survey of left ventricle wall stress models, their mechanics, stress computation and results. We have provided herein a compendium of major type of wall stress models: thin-wall models based on the Laplace law, thick-wall shell models, elasticity theory model, thick-wall large deformation models and finite element models. We have compared the mean stress values of these models as well as the variation of stress across the wall. All of the thin-wall and thick-wall shell models are based on idealised ellipsoidal and spherical geometries. However, the elasticity model's shape can vary through the cycle, to simulate the more ellipsoidal shape of the left ventricle in the systolic phase. The finite element models have more representative geometries, but are generally based on animal data, which limits their medical relevance. This paper can enable readers to obtain a comprehensive perspective of left ventricle wall stress models, of how to employ them to determine wall stresses, and be cognizant of the assumptions involved in the use of specific models.
12. 8. VIEW OF STUDDING, EXTERIOR WALL FURRING AND LINTELS FOR ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
8. VIEW OF STUDDING, EXTERIOR WALL FURRING AND LINTELS FOR NEW WINDOW OPENINGS. NORTH WING, FIRST FLOOR DURING REHABILITATION OF HOSPITAL BUILDING, 1938. PLEASE CREDIT: BUREAU OF YARDS AND DOCKS, NATIONAL ARCHIVES - U. S. Naval Asylum, Laning Hall, Gray's Ferry Avenue, Philadelphia, Philadelphia County, PA
13. 16. Interior view, greenhouse, south wall taken from the ground. ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
16. Interior view, greenhouse, south wall taken from the ground. The original floor height is indicated by the joists on the left. The large opening on the right was formerly fitted with an exterior-fed iron stove used to heat the space on particularly cold days. - John Bartram House & Garden, Greenhouse, 54th Street & LIndbergh Boulevard, Philadelphia, Philadelphia County, PA
14. Detail, steps and walls, east corner, Burton Park Amphitheater, view ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
Detail, steps and walls, east corner, Burton Park Amphitheater, view to west (90mm lens). Open doorway to left of steps leads to stage wing area; steps lead to Club House grade level. - Burton Park, Club House & Amphitheater, Adjacent ot south end of Chestnut Avenue, San Carlos, San Mateo County, CA
15. 8. FIRST FLOOR, EAST ROOM, NORTHEAST WALL SHOWING DOORWAYS TO ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
8. FIRST FLOOR, EAST ROOM, NORTHEAST WALL SHOWING DOORWAYS TO BOXED WINDER STAIRWAYS, UP ON FAR RIGHT AND DOWN TO RIGHT OF FIREPLACE, WITH SHUTTERS OPEN - High Farm, House, Creek Road, 1 mile West of Easton Road, Pipersville, Bucks County, PA
16. 6. View of mill wall ruins looking E showing arched ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
6. View of mill wall ruins looking E showing arched openings where fuel was fed to fire Jamaican Train. - Hacienda Azucarera La Esperanza, Mill (Ruins), 2.65 miles North of PR Route 2 Bridge Over Manati River, Manati, Manati Municipio, PR
17. Open Source, Openness, and Higher Education
ERIC Educational Resources Information Center
Wiley, David
2006-01-01
In this article David Wiley provides an overview of how the general expansion of open source software has affected the world of education in particular. In doing so, Wiley not only addresses the development of open source software applications for teachers and administrators, he also discusses how the fundamental philosophy of the open source…
18. 17. INTERIOR OF BEDROOM NUMBER TWO SHOWING OPEN DOOR TO ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
17. INTERIOR OF BEDROOM NUMBER TWO SHOWING OPEN DOOR TO BATHROOM NUMBER ONE AT EXTREME PHOTO LEFT, OPEN PANEL DOOR TO THE WALK-IN CLOSET AT PHOTO CENTER LEFT, OPEN PANEL DOOR TO HALL AT PHOTO CENTER RIGHT, AND A 6-LIGHT OVER 1-LIGHT SASH WINDOW ON THE WEST WALL AT PHOTO RIGHT. VIEW TO SOUTH. - Rush Creek Hydroelectric System, Clubhouse Cottage, Rush Creek, June Lake, Mono County, CA
19. Interwall Friction and Sliding Behavior of Centimeters Long Double-Walled Carbon Nanotubes.
PubMed
Zhang, Rufan; Ning, Zhiyuan; Xu, Ziwei; Zhang, Yingying; Xie, Huanhuan; Ding, Feng; Chen, Qing; Zhang, Qiang; Qian, Weizhong; Cui, Yi; Wei, Fei
2016-02-10
Here, we studied the interwall friction and sliding behaviors of double-walled carbon nanotubes (DWCNTs). The interwall friction shows a linear dependence on the pullout velocity of the inner wall. The axial curvature in DWCNTs causes the significant increase of the interwall friction. The axial curvature also affects the sliding behavior of the inner wall. Compared with the axial curvature, the opening ends of DWCNTs play tiny roles in their interwall friction.
20. Radial vibrations of BPS skyrmions
NASA Astrophysics Data System (ADS)
Adam, C.; Haberichter, M.; Romanczukiewicz, T.; Wereszczynski, A.
2016-11-01
We study radial vibrations of spherically symmetric Skyrmions in the Bogomol'nyi-Prasad-Sommerfield Skyrme model. Concretely, we numerically solve the linearized field equations for small fluctuations in a Skyrmion background, both for linearly stable oscillations and for (unstable) resonances. This is complemented by numerical solutions of the full nonlinear system, which confirm all the results of the linear analysis. In all cases, the resulting fundamental excitation provides a rather accurate value for the Roper resonance, supporting the hypothesis that the Bogomol'nyi-Prasad-Sommerfield Skyrme model already gives a reasonable approximate description of this resonance. Furthermore, for many potentials additional higher resonances appear, again in agreement with known experimental results.
1. Open access, open education resources and open data in Uganda.
PubMed
Salvo, Ivana Di; Mwoka, Meggie; Kwaga, Teddy; Rukundo, Priscilla Aceng; Ernest, Dennis Ssesanga; Osaheni, Louis Aikoriogie; John, Kasibante; Shafik, Kasirye; de Sousa, Agostinho Moreira
2015-01-01
As a follow up to OpenCon 2014, International Federation of Medical Students' Associations (IFMSA) students organized a 3 day workshop Open Access, Open Education Resources and Open Data in Kampala from 15-18 December 2014. One of the aims of the workshop was to engage the Open Access movement in Uganda which encompasses the scientific community, librarians, academia, researchers and students. The IFMSA students held the workshop with the support of: Consortium for Uganda University Libraries (CUUL), The Right to Research Coalition, Electronic Information for Libraries (EIFL), Makerere University, International Health Sciences University (IHSU), Pan African Medical Journal (PAMJ) and the Centre for Health Human Rights and Development (CEHURD). All these organizations are based or have offices in Kampala. The event culminated in a meeting with the Science and Technology Committee of Parliament of Uganda in order to receive the support of the Ugandan Members of Parliament and to make a concrete change for Open Access in the country.
2. Gullies in Crater Wall
NASA Technical Reports Server (NTRS)
2004-01-01
6 April 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies in the wall of a large impact crater in Newton Basin near 41.9oS, 158.1oW. Such gullies may have formed by downslope movement of wet debris--i.e., water. Unfortunately, because the responsible fluid (if there was one) is no longer present today, only the geomorphology of the channels and debris aprons can be used to deduce that water might have been involved. The image covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the upper left.
3. Tailoring the chirality of magnetic domain walls by interface engineering.
PubMed
Chen, Gong; Ma, Tianping; N'Diaye, Alpha T; Kwon, Heeyoung; Won, Changyeon; Wu, Yizheng; Schmid, Andreas K
2013-01-01
Contacting ferromagnetic films with normal metals changes how magnetic textures respond to electric currents, enabling surprisingly fast domain wall motions and spin texture-dependent propagation direction. These effects are attributed to domain wall chirality induced by the Dzyaloshinskii-Moriya interaction at interfaces, which suggests rich possibilities to influence domain wall dynamics if the Dzyaloshinskii-Moriya interaction can be adjusted. Chiral magnetism was seen in several film structures on appropriately chosen substrates where interfacial spin-orbit-coupling effects are strong. Here we use real-space imaging to visualize chiral domain walls in cobalt/nickel multilayers in contact with platinum and iridium. We show that the Dzyaloshinskii-Moriya interaction can be adjusted to stabilize either left-handed or right-handed Néel walls, or non-chiral Bloch walls by adjusting an interfacial spacer layer between the multilayers and the substrate. Our findings introduce domain wall chirality as a new degree of freedom, which may open up new opportunities for spintronics device designs.
4. Wall Street's growing influence on plastic surgery.
PubMed
Krieger, L M; Shaw, W W
2000-04-01
The advent of managed care has unleashed market forces on the health care system. One result of these new pressures is a shift from nonprofit to Wall Street-based financing. This report quantifies these trends by comparing health organizations' financial structures in the 1980s and now. The reasons behind this shift and the function of the stock market are examined. A review of Wall Street's key financial measures confirms that health care has shifted to the stock market as its principal means of financing. The stock market works by assigning a current price to a company's stock based on estimates for future earnings. Thus, companies desire predictability in their costs, revenues, and profits. Plastic surgeons can master this system by meeting the challenges imposed by Wall Street financing. Important steps include continuously measuring costs and outcomes of procedures, demanding cost data from hospitals and payers, using these data to improve costs and outcomes, and taking advantage of the system's openness to innovation and easier access to capital. As they seek to protect their role as medical decision makers under the new free-market system, plastic surgeons can benefit from understanding the mechanisms of the stock market.
5. Structure of axionic domain walls
NASA Astrophysics Data System (ADS)
Huang, M. C.; Sikivie, P.
1985-09-01
The structure of axionic domain walls is investigated using the low-energy effective theory of axions and pions. We derive the spatial dependence of the phases of the Peccei-Quinn scalar field and the QCD quark-antiquark condensates inside an axionic domain wall. Thence an accurate estimate of the wall surface energy density is obtained. The equations of motion for axions, photons, leptons, and baryons in the neighborhood of axionic domain walls are written down and estimates are given for the wall reflection and transmission coefficients of these particles. Finally, we discuss the energy dissipation by axionic domain walls oscillating in the early universe due to the reflection of particles in the primordial soup.
6. Oven wall panel construction
DOEpatents
Ellison, Kenneth; Whike, Alan S.
1980-04-22
An oven roof or wall is formed from modular panels, each of which comprises an inner fabric and an outer fabric. Each such fabric is formed with an angle iron framework and somewhat resilient tie-bars or welded at their ends to flanges of the angle irons to maintain the inner and outer frameworks in spaced disposition while minimizing heat transfer by conduction and permitting some degree of relative movement on expansion and contraction of the module components. Suitable thermal insulation is provided within the module. Panels or skins are secured to the fabric frameworks and each such skin is secured to a framework and projects laterally so as slidingly to overlie the adjacent frame member of an adjacent panel in turn to permit relative movement during expansion and contraction.
7. Crater Wall With Gullies
NASA Technical Reports Server (NTRS)
2004-01-01
8 June 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture shows gullies formed in the terraced wall of an impact crater on the floor of a larger crater near 39.1oS, 200.7oW. Gullies such as these are fairly common in craters and depressions at southern middle latitudes. They also occur in some areas at northern middle latitudes and in both polar regions. They may have formed by liquid water, or not--the Mars science community is still debating and discussing the issue. This picture covers an area about 3 km (1.9 mi) across. The scene is illuminated by sunlight from the upper left.
8. Open for Business
ERIC Educational Resources Information Center
Voyles, Bennett
2007-01-01
People know about the Sakai Project (open source course management system); they may even know about Kuali (open source financials). So, what is the next wave in open source software? This article discusses business intelligence (BI) systems. Though open source BI may still be only a rumor in most campus IT departments, some brave early adopters…
9. 13. LONG WEST WALL (LEFT) AND SHORT SOUTH WALL (RIGHT) ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
13. LONG WEST WALL (LEFT) AND SHORT SOUTH WALL (RIGHT) OF AR-9, ALSO SHOWING MORE RECENT CONTROL ROOM BUILDING AT RIGHT. VIEW IS TO THE NORTHEAST. - Edwards Air Force Base, South Base, Rammed Earth Aircraft Dispersal Revetments, Western Shore of Rogers Dry Lake, Boron, Kern County, CA
10. 10. VIEW OF LAMINARFLOW FILTER WALL NEAR SOUTH WALL OF ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
10. VIEW OF LAMINAR-FLOW FILTER WALL NEAR SOUTH WALL OF CLEAN ROOM (102). NOTE GROUNDING CABLES NEAR BASEBOARD IN LOWER RIGHT BACKGROUND. WHITE SQUARE IN FOREGROUND IS A FLOOR DRAIN COVERED WITH TAPE. - Vandenberg Air Force Base, Space Launch Complex 3, Vehicle Support Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA
11. North wall, central part, showing partial partition wall at left. ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
North wall, central part, showing partial partition wall at left. This area is labeled Pioneering Research on drawing copy NV-35-B-5 (submitted with HABS No. NV-35-B) (series 2 of 4) - Bureau of Mines Metallurgical Research Laboratory, Original Building, Date Street north of U.S. Highway 93, Boulder City, Clark County, NV
12. 7. INTERIOR, MAIN GARAGE, SOUTHERN WALL, FROM CLOSE TO WALL, ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
7. INTERIOR, MAIN GARAGE, SOUTHERN WALL, FROM CLOSE TO WALL, LOOKING SOUTH, SHOWING 'GAMEWELL' FIRE ALARM TAPE CONTROL SYSTEM (TECHNOLOGY CIRCA 1910) AT CENTER, AND ENTRY TO OFFICE AT FAR RIGHT. - Oakland Naval Supply Center, Firehouse, East of Fourth Street, between A & B Streets, Oakland, Alameda County, CA
13. The Mobile bypass Signal Arrests Shoot Growth by Disrupting Shoot Apical Meristem Maintenance, Cytokinin Signaling, and WUS Transcription Factor Expression1[OPEN
PubMed Central
Parrott, David L.; Adhikari, Emma; Fraser, Nisa
2016-01-01
The bypass1 (bps1) mutant of Arabidopsis (Arabidopsis thaliana) produces a root-sourced compound (the bps signal) that moves to the shoot and is sufficient to arrest growth of a wild-type shoot; however, the mechanism of growth arrest is not understood. Here, we show that the earliest shoot defect arises during germination and is a failure of bps1 mutants to maintain their shoot apical meristem (SAM). This finding suggested that the bps signal might affect expression or function of SAM regulatory genes, and we found WUSCHEL (WUS) expression to be repressed in bps1 mutants. Repression appears to arise from the mobile bps signal, as the bps1 root was sufficient to rapidly down-regulate WUS expression in wild-type shoots. Normally, WUS is regulated by a balance between positive regulation by cytokinin (CK) and negative regulation by CLAVATA (CLV). In bps1, repression of WUS was independent of CLV, and, instead, the bps signal down-regulates CK responses. Cytokinin treatment of bps1 mutants restored both WUS expression and activity, but only in the rib meristem. How the bps signal down-regulates CK remains unknown, though the bps signal was sufficient to repress expression of one CK receptor (AHK4) and one response regulator (AHP6). Together, these data suggest that the bps signal pathway has the potential for long-distance regulation through modification of CK signaling and altering gene expression. PMID:27208247
14. VIEW OF MACHINE SHOP STORAGE OPENINGS, NORTH END OF BARN, ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
VIEW OF MACHINE SHOP STORAGE OPENINGS, NORTH END OF BARN, LOOKING SOUTH (This northern-most facade of the barn was originally a board and batten wall with two sliding doors. In the early decades of the twentieth century Frederick Edward Arnold moved the wall and doors; they now make up the north end of bay 3. This was done to ease machine storage) - Arnold Farm, Barn, 1948 Arnold Road, Coupeville, Island County, WA
15. Transonic interference reduction by limited ventilation wall panels
NASA Technical Reports Server (NTRS)
Lee, John D.
1986-01-01
In two wind tunnels used for the two-dimensional airfoil tests, each wall above and below the model was modified by replacing small segments of the solid boundaries with perforated plates vented into sealed chambers. Perforated segments having approximately 40 percent open area were found to reduce the transonic wall interference to a negligible level, for a model chord-to-tunnel height ratio of 0.5. This report describes the physical arrangement and presents typical model pressure distributions to illustrate the effectiveness of the technique.
16. Association Mapping of Cell Wall Synthesis Regulatory Genes and Cell Wall Quality in Switchgrass
SciTech Connect
Bartley, Laura; Wu, Y.; Zhu, L.; Brummer, E. C.; Saha, M.
2016-05-31
transcription factors from the rice gene network. Eight of fifteen (53%) of these have not previously been examined for this function. Some of these may represent novel grass-diverged cell wall regulators, while others are likely to have this function across angiosperms. A parallel effort of this project to expand knowledge of enzymes that have evolved to function in grass cell wall synthesis, revealed that a grass-diverged enzyme in rice, OsAT5, ferulates monolignols that are naturally incorporated into grass cell walls. This finding opens potential natural selection avenues for improving biomass composition for downstream processing by weak base pretreatment. Thus, this project has significantly expanded knowledge of cell wall synthesis and regulation in rice, information that can be used in reverse genetics and synthetic biology approaches to re-engineer cell walls for improved production of biofuel and high-value products. To lay the foundation for translating these results directly for switchgrass improvement, the project employed a comparative phylogenetic analysis of the major group of cell wall transcription factors that have been found to function in cell wall regulation, the R2R3 MYBs. This analysis concluded that known cell wall regulators are largely conserved across switchgrass, rice, maize, poplar, and Arabidopsis. This interpretation is also largely consistent with the gene network analysis described above, though both approaches provide evidence that some co-orthologs of Arabidopsis regulators have diminished or increased in importance based on gene expression patterns. Also, several clades containing dicot cell wall regulators have expanded, consistent with the evolution of new cell wall regulators. This latter result is supported by functional analysis of the R2R3 MYB protein SWAM1 in a collaboration between this project and the DOE-funded group of Dr. S. Hazen at the University of
17. Segmentation, statistical analysis, and modelling of the wall system in ceramic foams
SciTech Connect
Kampf, Jürgen; Schlachter, Anna-Lena; Redenbach, Claudia; Liebscher, André
2015-01-15
Closed walls in otherwise open foam structures may have a great impact on macroscopic properties of the materials. In this paper, we present two algorithms for the segmentation of such closed walls from micro-computed tomography images of the foam structure. The techniques are compared on simulated data and applied to tomographic images of ceramic filters. This allows for a detailed statistical analysis of the normal directions and sizes of the walls. Finally, we explain how the information derived from the segmented wall system can be included in a stochastic microstructure model for the foam.
18. Vesicles between plasma membrane and cell wall prior to visible senescence of Iris and Dendrobium flowers.
PubMed
Kamdee, Channatika; Kirasak, Kanjana; Ketsa, Saichol; van Doorn, Wouter G
2015-09-01
Cut Iris flowers (Iris x hollandica, cv. Blue Magic) show visible senescence about two days after full opening. Epidermal cells of the outer tepals collapse due to programmed cell death (PCD). Transmission electron microscopy (TEM) showed irregular swelling of the cell walls, starting prior to cell collapse. Compared to cells in flowers that had just opened, wall thickness increased up to tenfold prior to cell death. Fibrils were visible in the swollen walls. After cell death very little of the cell wall remained. Prior to and during visible wall swelling, vesicles (paramural bodies) were observed between the plasma membrane and the cell walls. The vesicles were also found in groups and were accompanied by amorphous substance. They usually showed a single membrane, and had a variety of diameters and electron densities. Cut Dendrobium hybrid cv. Lucky Duan flowers exhibited visible senescence about 14 days after full flower opening. Paramural bodies were also found in Dendrobium tepal epidermis and mesophyll cells, related to wall swelling and degradation. Although alternative explanations are well possible, it is hypothesized that paramural bodies carry enzymes involved in cell wall breakdown. The literature has not yet reported such bodies in association with senescence/PCD.
19. Moisture Research - Optimizing Wall Assemblies
SciTech Connect
Arena, L.; Mantha, P.
2013-05-01
The Consortium for Advanced Residential Buildings (CARB) evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls.
20. The Wonders of Word Walls.
ERIC Educational Resources Information Center
Houle, Amy; Krogness, Allison
2001-01-01
Describes using a word wall, a visible display categorizing words alphabetically, enabling children in early childhood classrooms to discover new words and to practice and expand their language skills. Suggests that a word wall helps to create a secure learning environment, builds student confidence, and contributes to independent reading and…
1. The "Brick Wall" Graphic Organizer
ERIC Educational Resources Information Center
Matteson, Shirley M.
2016-01-01
A brick wall provides a fitting description of what happens when teachers try to teach a concept for which students are unprepared. When students are unsuccessful academically, their foundational knowledge may be missing, incomplete, or incorrect. As a result, students "hit a brick wall," and their academic progress stops because they do…
2. Great Wall of China
NASA Technical Reports Server (NTRS)
2001-01-01
This ASTER sub-image covers a 12 x 12 km area in northern Shanxi Province, China, and was acquired January 9, 2001. The low sun angle, and light snow cover highlight a section of the Great Wall, visible as a black line running diagonally through the image from lower left to upper right. The Great Wall is over 2000 years old and was built over a period of 1000 years. Stretching 4500 miles from Korea to the Gobi Desert it was first built to protect China from marauders from the north.
This image is located at 40.2 degrees north latitude and 112.8 degrees east longitude.
Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.
The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands Evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and
3. Rough-Wall Channel Analysis Using Suboptimal Control Theory
NASA Technical Reports Server (NTRS)
Flores, O.; Jimenez, J.; Tenpleton, J.
2003-01-01
The original aim of this work was to shed some light on the physics of turbulence over rough walls using large-eddy simulations and the suboptimal-control wall boundary conditions introduced by Nicoud et al. It was hoped that, if that algorithm was used to fit the mean velocity profile of the simulations to that of a rough-walled channel, instead of to a smooth one, the wall stresses introduced by the control algorithm would give some indication of what aspects of rough walls are most responsible for the modification of the flow in real turbulence. It was similarly expected that the structure of the resulting velocity fluctuations would share some of the characteristics of rough-walled flows, thus again suggesting what is intrinsic and what is accidental in the effect of geometric wall roughness. A secondary goal was to study the effect of 'unphysical' boundary conditions on the outside flow by observing how a relatively major change of the target velocity profile, and therefore presumably of the applied wall stresses, modifies properties such as the dominant length scales of the velocity fluctuations away from the wall. As will be seen below, this secondary goal grew more important during the course of the study, which was carried out during a short summer visit of the first two authors to the CTR. It became clear that there are open questions about the way in which the control algorithm models the boundary conditions, even for smooth walls, and that these questions make the physical interpretation of the results difficult. Considerable more work in that area seems to be needed before even relatively advanced large-eddy simulations, such as these, can be used to draw conclusions about the physics of wall-bounded turbulent flows. The numerical method is the same as in Nicoud et al. The modifications introduced in the original code are briefly described in section 2, but the original paper should be consulted for a full description of the algorithm. The results are
4. Channel Wall Landslides
NASA Technical Reports Server (NTRS)
2005-01-01
[figure removed for brevity, see original site]
The multiple landslides in this VIS image occur along a steep channel wall. Note the large impact crater in the context image. The formation of the crater may have initially weakened that area of the surface prior to channel formation.
Image information: VIS instrument. Latitude -2.7, Longitude 324.8 East (35.2 West). 19 meter/pixel resolution.
Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.
NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.
5. Open Smart Energy Gateway (OpenSEG)
SciTech Connect
2014-09-01
The Open Smart Energy Gateway (OpenSEG) aims to provide near-real time smart meter data to consumers without the delays or latencies associated with it being transported to the utility data center and then back to the consumer's application. To do this, the gateway queries the local Smart Meter to which it is bound to get energy consumption information at pre-defined intervals (minimum interval is 4 seconds). OpenSEG then stores the resulting data internally for retrieval by an external application.
6. Wall Shear Stress, Wall Pressure and Near Wall Velocity Field Relationships in a Whirling Annular Seal
NASA Technical Reports Server (NTRS)
Morrison, Gerald L.; Winslow, Robert B.; Thames, H. Davis, III
1996-01-01
The mean and phase averaged pressure and wall shear stress distributions were measured on the stator wall of a 50% eccentric annular seal which was whirling in a circular orbit at the same speed as the shaft rotation. The shear stresses were measured using flush mounted hot-film probes. Four different operating conditions were considered consisting of Reynolds numbers of 12,000 and 24,000 and Taylor numbers of 3,300 and 6,600. At each of the operating conditions the axial distribution (from Z/L = -0.2 to 1.2) of the mean pressure, shear stress magnitude, and shear stress direction on the stator wall were measured. Also measured were the phase averaged pressure and shear stress. These data were combined to calculate the force distributions along the seal length. Integration of the force distributions result in the net forces and moments generated by the pressure and shear stresses. The flow field inside the seal operating at a Reynolds number of 24,000 and a Taylor number of 6,600 has been measured using a 3-D laser Doppler anemometer system. Phase averaged wall pressure and wall shear stress are presented along with phase averaged mean velocity and turbulence kinetic energy distributions located 0.16c from the stator wall where c is the seal clearance. The relationships between the velocity, turbulence, wall pressure and wall shear stress are very complex and do not follow simple bulk flow predictions.
7. [An example of multi-stage reconstruction of a full-thickness abdominal wall defect].
PubMed
Kaczmarzyk, Janusz; Elsaftawy, Ahmed; Jabłecki, Jerzy; Kaczmarzyk, Leszek
2013-01-01
Abdominal wall reconstruction is a highly complex procedure that may requires a multiple stages surgical operations. The aim of a such reconstruction is to close the abdominal wall defect and to create a support for the internal organs. It's a challenge for both general and reconstructive surgery. An incomplete thickness defects of the abdominal wall are so much easier to challenge than complete ones. Also the size of the primary defect determines the way and stages of the operation. Such defects can occur in necrotizing fasciitis of the abdominal wall, after abdominal walls tumors removal, in traffic accidents or after "open abdomen" procedures (acute severe pancreatitis). In this paper the authors present a case of 62-yo patient which was operated because of large intestine perforation with various complications of which the most serious was the abdominal wall defect.
8. Denitrification Walls: Successes and Limitations.
NASA Astrophysics Data System (ADS)
Schipper, L. A.; Barkle, G. F.; Burgess, C. P.; Vojvodic-Vukovic, M.
2001-05-01
There is a need to develop practical and inexpensive approaches for removing nitrate from ground water because of its potential adverse effect on receiving aquatic environments. Denitrification walls may be one such approach for removing nitrate from shallow groundwater. In January 1996, we constructed a denitrification wall by digging a trench that intercepted groundwater and mixed the excavated soil with sawdust before the mix was returned to the trench. Sawdust provides a source of energy for denitrifying bacteria, which convert nitrate in groundwater entering the wall to nitrogen gas. For the past 5 years, nitrate concentrations in groundwater entering this wall have ranged from 5 to 16 mg N L-1 but have always been reduced to less than 2 mg N L-1 in the wall indicating nearly complete removal of nitrate from the groundwater. We showed that this nitrate removal could be accounted for by denitrification rates which ranged from 0.6 to 18.1 mg N m-3 h-1. More recently we have encountered problems with denitrification walls constructed into coarsely textured soils (such as sands) where the addition of sawdust decreased hydraulic conductivity. As a consequence groundwater flowed under rather than through the wall. We are attempting to circumvent this problem using coarser grades of carbon amendments. Particulate carbon (such as sawdust) is likely to support lower rates of nitrate removal, but for longer, than soluble carbon sources because solid carbon sources degrade more slowly.
9. Gallbladder removal - open
MedlinePlus
... the surgeon needs to switch to an open surgery if laparoscopic surgery cannot be successfully continued. Other reasons for removing the gallbladder by open surgery: Unexpected bleeding during the laparoscopic operation Obesity Pancreatitis (inflammation in the pancreas) Pregnancy ( ...
10. On the mechanics of thin-walled laminated composite beams
NASA Astrophysics Data System (ADS)
Barbero, Ever J.; Lopez-Anido, Roberto; Davalos, Julio F.
1993-01-01
A formal engineering approach of the mechanics of thin-walled laminated beams based on kinematic assumptions consistent with Timoshenko beam theory is presented. Thin-walled composite beams with open or closed cross section subjected to bending and axial load are considered. A variational formulation is employed to obtain a comprehensive description of the structural response. Beam stiffness coefficients, which account for the cross section geometry and for the material anisotropy, are obtained. An explicit expression for the static shear correction factor of thin-walled composite beams is derived from energy equivalence. A numerical example involving a laminated I-beam is used to used to demonstrate the capability of the model for predicting displacements and ply stresses.
11. Method for making generally cylindrical underground openings
DOEpatents
Routh, J.W.
1983-05-26
A rapid, economical and safe method for making a generally cylindrical underground opening such as a shaft or a tunnel is described. A borehole is formed along the approximate center line of where it is desired to make the underground opening. The borehole is loaded with an explodable material and the explodable material is detonated. An enlarged cavity is formed by the explosive action of the detonated explodable material forcing outward and compacting the original walls of the borehole. The enlarged cavity may be increased in size by loading it with a second explodable material, and detonating the second explodable material. The process may be repeated as required until the desired underground opening is made. The explodable material used in the method may be free-flowing, and it may be contained in a pipe.
12. Development of a Chest Wall Protector Effective in Preventing Sudden Cardiac Death by Chest Wall Impact (Commotio Cordis)
PubMed Central
Kumar, Kartik; Mandleywala, Swati N.; Gannon, Michael P.; Estes, Nathan Anthony Mark; Weinstock, Jonathan
2017-01-01
Objective: Commotio cordis, sudden death with chest impact, occurs clinically despite chest wall protectors worn in sports. In an experimental model of commotio cordis, commercially available chest wall protectors failed to prevent ventricular fibrillation (VF). The goal of the current investigation was to develop a chest wall protector effective in the prevention of commotio cordis. Design: In the Tufts experimental model of commotio cordis the ability of chest protectors to prevent VF was assessed. Impacts were delivered with a 40-mph lacrosse ball, timed to the vulnerable period for VF. Intervention: A chest wall protector or no chest wall protector (control) was randomly assigned to be placed over the chest. Four iterative series of 2 to 4 different chest wall material combinations were assessed. Materials included 3 different foams (Accelleron [Unequal Technologies, Glen Mills, PA], closed cell high density foam; Airilon [Unequal Technologies, Glen Mills, PA], closed cell low density soft foam; and an open cell memory foam) that were adhered to a layer of TriDur (Unequal Technologies, Glen Mills, PA), a flexible elastomeric coated aramid that was bonded to a semirigid polypropylene polymer (ImpacShield, Unequal Technologies, Glen Mills, PA). Main Outcome Measure: Induction of VF by chest wall impact was the primary outcome. Results: Of 80 impacts without chest protectors, 43 (54%) resulted in VF. Ventricular fibrillation with chest protectors ranged from a high of 60% to a low of 5%. Of 12 chest protectors assessed, only 3 significantly lowered the risk of VF compared with impacts without chest protectors. These 3 chest protectors were combinations of Accelleron, Airilon, TriDur, and ImpacShield of different thicknesses. Protection increased linearly with the thicker combinations. Conclusions: Effective protection against VF with chest wall protection can be achieved in an experimental model of commotio cordis. Clinical Relevance: Chest protector designs
13. 27. "TEST STAND; STRUCTURAL; SIDEWALL, NORTH WALL AND SOUTH WALL ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
27. "TEST STAND; STRUCTURAL; SIDEWALL, NORTH WALL AND SOUTH WALL FRAMING ELEVATIONS." Specifications No. ENG-04353-55-72; Drawing No. 60-09-12; sheet 27 of 148; file no. 1320/78. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract no. 4338, Rev. B; date: 15 April 1957. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA
14. Economics of abdominal wall reconstruction.
PubMed
Bower, Curtis; Roth, J Scott
2013-10-01
The economic aspects of abdominal wall reconstruction are frequently overlooked, although understandings of the financial implications are essential in providing cost-efficient health care. Ventral hernia repairs are frequently performed surgical procedures with significant economic ramifications for employers, insurers, providers, and patients because of the volume of procedures, complication rates, the significant rate of recurrence, and escalating costs. Because biological mesh materials add significant expense to the costs of treating complex abdominal wall hernias, the role of such costly materials needs to be better defined to ensure the most cost-efficient and effective treatments for ventral abdominal wall hernias.
15. OTVE combustor wall condition monitoring
NASA Technical Reports Server (NTRS)
Szemenyei, Brian; Nelson, Robert S.; Barkhoudarian, S.
1989-01-01
Conventional ultrasonics, eddy current, and electromagnetic acoustic transduction (EMAT) technologies were evaluated to determine their capability of measuring wall thickness/wear of individual cooling channels in test specimens simulating conditions in the throat region of an OTVE combustion chamber liner. Quantitative results are presented for the eddy current technology, which was shown to measure up to the optimum 20-mil wall thickness with near single channel resolution. Additional results demonstrate the capability of the conventional ultrasonics and EMAT technologies to detect a thinning or cracked wall. Recommendations for additional eddy current and EMAT development tests are presented.
16. Open Access Alternatives
ERIC Educational Resources Information Center
Tenopir, Carol
2004-01-01
Open access publishing is a hot topic today. But open access publishing can have many different definitions, and pros and cons vary with the definitions. Open access publishing is especially attractive to companies and small colleges or universities that are likely to have many more readers than authors. A downside is that a membership fee sounds…
17. Openness as infrastructure
PubMed Central
2011-01-01
The advent of open access to peer reviewed scholarly literature in the biomedical sciences creates the opening to examine scholarship in general, and chemistry in particular, to see where and how novel forms of network technology can accelerate the scientific method. This paper examines broad trends in information access and openness with an eye towards their applications in chemistry. PMID:21999327
18. In Brief: Open government
NASA Astrophysics Data System (ADS)
Showstack, Randy
2010-03-01
U.S. President Barack Obama's Memorandum on Transparency and Open Government requires federal agencies to take steps toward increased transparency, public participation, and collaboration. Agencies are accepting suggestions until 19 March 2010. For more information, visit http://www.whitehouse.gov/open and http://www.usa.gov/webcontent/open/tool_poc.shtml.
19. Open Rotor Development
NASA Technical Reports Server (NTRS)
Van Zante, Dale E.; Rizzi, Stephen A.
2016-01-01
The ERA project executed a comprehensive test program for Open Rotor aerodynamic and acoustic performance. System studies used the data to estimate the fuel burn savings and acoustic margin for an aircraft system with open rotor propulsion. The acoustic measurements were used to produce an auralization that compares the legacy blades to the current generation of open rotor designs.
20. Lumbar (Open) Microscopic Discectomy
MedlinePlus
... When the outer wall of a disc, the annulus fibrosus, becomes weakened, it may tear allowing the ... and alleviate the pain. The surgery involves a small incision in the skin over the spine, removal ...
1. Penetration of the LCLS Injector Shield Wall at Sector 20
SciTech Connect
Dowell, D
2010-12-10
Penetrations through the LCLS injector shield wall are needed for the alignment of the accelerator, a diagnostic laser beam and utilities, and are shown in figure 1. The 1-inch diameter LCLS injector beam tube is blocked by the PPS stopper when the injector side of the wall is occupied. The two 3-inch diameter penetrations above and to the left of the beam tube are used by Precision Alignment and will be open only during installation of the injector beamline. Additional 3-inch diameter penetrations are for laser beams which will be used for electron beam diagnostics. These will not be plugged when the injector occupied. Other penetrations for the RF waveguide and other utilities are approximately 13-inch from the floor and as such are far from the line-of-sight of any radiation sources. The waveguide and utility penetrations pass only through the thicker wall as shown in the figure. The principal issue is with the two laser penetrations, since these will be open when the linac is operating and people are in the LCLS injector area. A principal concern is radiation streaming through the penetrations due to direct line-of sight of the PEP-2 lines. To answer this, fans of rays were traced through the 3-inch diameter laser penetrations as shown in Figures 2 and 3. Figure 2 gives the top view of the shield walls, the main linac and PEP-2 lines, and the ray-fans. The fans appear to originate between the walls since their angular envelope is defined by the greatest angle possible when rays are just on the 3-inch diameter at the inner most and outermost wall surfaces. The crossovers of all possible rays lie half way between these two surfaces. As the end-on view of Figure 3 clearly shows, there is no direct line-of-sight through the laser penetrations of the PEP-2 or linac beamlines.
2. Domain Wall Motion by the Magnonic Spin Seebeck Effect
NASA Astrophysics Data System (ADS)
Hinzke, D.; Nowak, U.
2011-07-01
The recently discovered spin Seebeck effect refers to a spin current induced by a temperature gradient in a ferromagnetic material. It combines spin degrees of freedom with caloric properties, opening the door for the invention of new, spin caloritronic devices. Using spin model simulations as well as an innovative, multiscale micromagnetic framework we show that magnonic spin currents caused by temperature gradients lead to spin transfer torque effects, which can drag a domain wall in a ferromagnetic nanostructure towards the hotter part of the wire. This effect opens new perspectives for the control and manipulation of domain structures.
3. Domain wall motion by the magnonic spin Seebeck effect.
PubMed
Hinzke, D; Nowak, U
2011-07-08
The recently discovered spin Seebeck effect refers to a spin current induced by a temperature gradient in a ferromagnetic material. It combines spin degrees of freedom with caloric properties, opening the door for the invention of new, spin caloritronic devices. Using spin model simulations as well as an innovative, multiscale micromagnetic framework we show that magnonic spin currents caused by temperature gradients lead to spin transfer torque effects, which can drag a domain wall in a ferromagnetic nanostructure towards the hotter part of the wire. This effect opens new perspectives for the control and manipulation of domain structures.
4. Theory of thin-walled rods
NASA Technical Reports Server (NTRS)
Goldenveizer, A L
1951-01-01
Starting with the Love equations for bending of extensible shells, "principal stress states" are sought for a thin-walled rod of arbitrary but open cross section. Principal stress states exclude those local states arising from end conditions which damp out with distance from the ends. It is found that for rods of intermediate length, long enough to avoid local bending at a support, and short enough that elementary torsion and bending are not the most significant stress states, four principal states exist. Three of these states are associated with the planar distribution of axial stress and are equivalent to the engineering theory of extension and bending of solid sections. The fourth state resembles that which has been called in the literature "bending stress due to torsional", except that cross sections are permitted to bend and the shear along the center line of the cross section is permitted to differ from zero.
5. An Exploration of Wall Retrofit Best Practices
SciTech Connect
Stovall, Therese K; Petrie, Thomas; Kosny, Jan; Childs, Phillip W; Atchley, Jerald Allen; Hulvey, Kimberly D
2007-01-01
A series of experiments were performed to examine wall retrofit options including replacing the cladding, adding insulation under the cladding, and multiple sealing methods that can be used when installing replacement windows in well-built or loosely-built rough openings. These experiments included thermal measurements in a hot box and air-leakage measurements. The retrofit claddings considered included wood-lap siding, vinyl siding, and vinyl siding with an integrated and formed foam insulation. Retrofit insulations included expanded and extruded polystyrene and foil-faced polyisocyanurate in various thicknesses. Air sealing methods for replacement windows included traditional caulking, exterior trim variations, loose-fill fiberglass, low-expansion foam, self-expanding foam inserts, and specialty tape. Results were applied to a model to estimate whole-house energy impacts for multiple climates.
6. Open inflation in the landscape
NASA Astrophysics Data System (ADS)
Yamauchi, Daisuke; Linde, Andrei; Naruko, Atsushi; Sasaki, Misao; Tanaka, Takahiro
2011-08-01
The open inflation scenario is attracting a renewed interest in the context of the string landscape. Since there are a large number of metastable de Sitter vacua in the string landscape, tunneling transitions to lower metastable vacua through the bubble nucleation occur quite naturally, which leads to a natural realization of open inflation. Although the deviation of Ω0 from unity is small by the observational bound, we argue that the effect of this small deviation on the large-angle CMB anisotropies can be significant for tensor-type perturbation in the open inflation scenario. We consider the situation in which there is a large hierarchy between the energy scale of the quantum tunneling and that of the slow-roll inflation in the nucleated bubble. If the potential just after tunneling is steep enough, a rapid-roll phase appears before the slow-roll inflation. In this case the power spectrum is basically determined by the Hubble rate during the slow-roll inflation. On the other hand, if such a rapid-roll phase is absent, the power spectrum keeps the memory of the high energy density there in the large angular components. Furthermore, the amplitude of large angular components can be enhanced due to the effects of the wall fluctuation mode if the bubble wall tension is small. Therefore, although even the dominant quadrupole component is suppressed by the factor (1-Ω0)2, one can construct some models in which the deviation of Ω0 from unity is large enough to produce measurable effects. We also consider a more general class of models, where the false vacuum decay may occur due to Hawking-Moss tunneling, as well as the models involving more than one scalar field. We discuss scalar perturbations in these models and point out that a large set of such models is already ruled out by observational data, unless there was a very long stage of slow-roll inflation after the tunneling. These results show that observational data allow us to test various assumptions concerning
7. Radiative feedback in Helmholtz resonators with more than one opening.
PubMed
Dosch, Hans Günter
2016-11-01
The resonance frequency of a Helmholtz resonator with several openings is derived, taking into account the radiation feedback between the different holes. This is done under the assumption that the distance between the openings is large as compared to their linear dimensions. The effect of a finite wall thickness of the resonator is also discussed. The radiation feedback can lead to a shift of the resonance position by more than 10%.
8. 18. BATHROOM INTERIOR SHOWING OPEN DOOR TO SOUTH BEDROOM AT ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
18. BATHROOM INTERIOR SHOWING OPEN DOOR TO SOUTH BEDROOM AT PHOTO CENTER, TOILET AT EXTREME PHOTO RIGHT BOTTOM, OPEN DOOR TO MEDICINE CABINET AT PHOTO RIGHT. A WALLPAPER WAINSCOT COVERS THE LOWER PORTION OF THE ORIGINAL FIBERBOARD WALL COVERING. THE FLOOR IS LINOLEUM. VIEW TO SOUTHEAST. - Big Creek Hydroelectric System, Big Creek Town, Operator House, Orchard Avenue south of Huntington Lake Road, Big Creek, Fresno County, CA
9. 6. INTERIOR OF LIVING ROOM SHOWING OPEN DOORWAY TO KITCHEN ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
6. INTERIOR OF LIVING ROOM SHOWING OPEN DOORWAY TO KITCHEN AT PHOTO CENTER, FLUSH FRONT DOOR WITH GLAZING AT PHOTO RIGHT, AND OPEN PANELED DOOR TO BEDROOM NO. 2 AT LEFT PHOTO CENTER. DECORATIVE WOOD STRIPPING ON WALLS AND CEILING IS CARRIED THROUGHOUT REST OF ORIGINAL PORTION OF HOUSE. VIEW TO NORTH. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA
10. INTERIOR OF EAST DOOR, SOUTH WALL, AND AISLE LOOKING EAST ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
INTERIOR OF EAST DOOR, SOUTH WALL, AND AISLE LOOKING EAST (This bay of the barn was originally used for livestock. Horse pens and milking stanchions remain. Floor was built with 1/4 inch gaps between the planks to allow air circulation. Photograph also shows the knee-high hinged doors that open for easy removal of manure) - Arnold Farm, Barn, 1948 Arnold Road, Coupeville, Island County, WA
11. Fluorescence correlation spectroscopy in semiadhesive wall proximity.
PubMed
Sanguigno, Luigi; De Santo, Ilaria; Causa, Filippo; Netti, Paolo A
2011-11-01
With examination of diffusion in heterogeneous media through fluorescence correlation spectroscopy, the temporal correlation of the intensity signal shows a long correlation tail and the characteristic diffusion time results are no longer easy to determine. Excluded volume and sticking effects have been proposed to justify such deviations from the standard behavior since all contribute and lead to anomalous diffusion mechanisms . Usually, the anomalous coefficient embodies all the effects of environmental heterogeneity providing too general explanations for the exotic diffusion recorded. Here, we investigated whether the reason of anomalies could be related to a lack of an adequate interpretative model for heterogeneous systems and how the presence of obstacles on the detection volume length scale could affect fluorescence correlation spectroscopy experiments. We report an original modeling of the autocorrelation function where fluorophores experience reflection or adsorption at a wall placed at distances comparable with the detection volume size. We successfully discriminate between steric and adhesion effects through the analysis of long time correlations and evaluate the adhesion strength through the evaluation of probability of being adsorbed and persistence time at the wall on reference data. The proposed model can be readily adopted to gain a better understanding of intracellular and nanoconfined diffusion opening the way for a more rational analysis of the diffusion mechanism in heterogeneous systems and further developing biological and biomedical applications.
12. Interference on an airfoil of finite span in an open wind tunnel
NASA Technical Reports Server (NTRS)
Theodorsen, Theodore
1934-01-01
The wall interference on an airfoil of finite span in an open-throat rectangular section has been treated theoretically and the result is presented in a convenient formula. Numerical results are given in tables and diagrams.
13. Fly on the Wall
NASA Technical Reports Server (NTRS)
Mulenburg, Gerald
2003-01-01
14. My Big Wall
NASA Technical Reports Server (NTRS)
Espinosa, Paul S.
2002-01-01
It was June and I was in Yosemite National Park in California, 2,000-feet off the ground. I was climbing El Capitan, a majestic 3,000-foot high, mile-wide granite monolith--one of the most sought after and spectacular rock climbs in the world. After three days of climbing on its sheer face, and having completed the most difficult part of the route, my partner and I were heading down. A thunderstorm lasting all night and into the morning had soaked our tiny perch and all our worldly possessions. We began rappelling down the vertical wall by sliding to the ends of two 50meter ropes tied together and looped through a set of fixed rings bolted into the rock. At the end of the ropes was another rappel station consisting of a set of rings, placed by previous climbers for retreating parties, which we used to anchor ourselves to the rock face. We then pulled the ropes down from the rings above, threaded the ones in front of our noses and started down another rope length. Everything we brought up for our five-day climb to the summit we had to bring back down with us: ropes, climbing gear of every sort, sleeping bags, extra clothes, food, water, and other essentials. All this we either stuffed into a haul bag (an oversized reinforced duffel bag) or slung over our shoulders. The retreat was slow and methodical, akin to a train backing down a mountain, giving me ample time to think. My situation made me think about my work, mostly, about all the projects I have managed, or been involved in managing. As a NASA project manager, I have worked on a number of successful projects. I have also been involved in a number of projects I never saw the end of. I thought about all the projects I transferred off of for other opportunities, projects that were in full stride and ran out of funding, and ones put on the shelf because they would not meet a flight date. Oh yes, I have had many success, to be sure, or I would have burned out years ago. Lessons from both the successful and not
15. Simulation of turbulent wall pressure
NASA Technical Reports Server (NTRS)
Ash, R. L.
1976-01-01
A computer program has been developed to simulate the transient wall pressure field produced by a low speed fully turbulent boundary layer. The theoretical basis for the simulation has been discussed and preliminary results from a pressure simulation are presented.
16. Plant cell walls to ethanol.
Technology Transfer Automated Retrieval System (TEKTRAN)
Conversion of plant cell walls to ethanol constitutes generation 2 bioethanol production. The process consists of several steps: biomass selection/genetic modification, physiochemical pretreatment, enzymatic saccharification, fermentation, and separation. Ultimately, it is desired to combine as man...
17. Wall effects in wind tunnels
NASA Technical Reports Server (NTRS)
Chevallier, J. P.; Vaucheret, X.
1986-01-01
A synthesis of current trends in the reduction and computation of wall effects is presented. Some of the points discussed include: (1) for the two-dimensional, transonic tests, various control techniques of boundary conditions are used with adaptive walls offering high precision in determining reference conditions and residual corrections. A reduction in the boundary layer effects of the lateral walls is obtained at T2; (2) for the three-dimensional tests, the methods for the reduction of wall effects are still seldom applied due to a lesser need and to their complexity; (3) the supports holding the model of the probes have to be taken into account in the estimation of perturbatory effects.
18. Hall thruster with grooved walls
NASA Astrophysics Data System (ADS)
Li, Hong; Ning, Zhongxi; Yu, Daren
2013-02-01
Axial-oriented and azimuthal-distributed grooves are formed on channel walls of a Hall thruster after the engine undergoes a long-term operation. Existing studies have demonstrated the relation between the grooves and the near-wall physics, such as sheath and electron near-wall transport. The idea to optimize the thruster performance with such grooves was also proposed. Therefore, this paper is devoted to explore the effects of wall grooves on the discharge characteristics of a Hall thruster. With experimental measurements, the variations on electron conductivity, ionization distribution, and integrated performance are obtained. The involved physical mechanisms are then analyzed and discussed. The findings help to not only better understand the working principle of Hall thruster discharge but also establish a physical fundamental for the subsequent optimization with artificial grooves.
19. Openness, Web 2.0 Technology, and Open Science
ERIC Educational Resources Information Center
Peters, Michael A.
2010-01-01
Open science is a term that is being used in the literature to designate a form of science based on open source models or that utilizes principles of open access, open archiving and open publishing to promote scientific communication. Open science increasingly also refers to open governance and more democratized engagement and control of science…
20. Will this open space work?
PubMed
Vischer, J
1999-01-01
Northern Oil is moving offices, and CEO Fritz Schumacher wants to make the most of the move in this fictional case study. He believes that adopting an open-plan work space will reinvent how the company works, not to mention cut costs. Facilities manager Sasha Pasternak also supports the open plan. Her job would be easier, and her budget would stretch further, if Northern had standardized workstations and used partitions, not walls. And she likes the way the new design flattens the organization: everyone has the same amount of space and the same ergonomically sound furniture. The new building would have more conference rooms and just-in-time work spaces for employees who worked mostly off-site. And although she knew that initial meetings between the architects and Northern employees hadn't yielded much support for open space--people were attached to their private offices--she expected that people would warm to the idea. But when the new design was unveiled, employees were less than enthusiastic. They hurled questions like, How will workers concentrate if they can't shut their office doors? How will people have confidential meetings with their boss? And why would people stay at Northern when the competition offers them private offices? There was even talk of circulating a petition refusing to move to the new space. A week later, the architect presented revised plans to the project group. The new options would add costs and reduce the amount of space savings, but offering a choice to employees might make them feel less threatened. What should the project team do? Five commentators offer advice.
1. Transmembrane passage of hydrophobic compounds through a protein channel wall.
PubMed
Hearn, Elizabeth M; Patel, Dimki R; Lepore, Bryan W; Indic, Mridhu; van den Berg, Bert
2009-03-19
Membrane proteins that transport hydrophobic compounds have important roles in multi-drug resistance and can cause a number of diseases, underscoring the importance of protein-mediated transport of hydrophobic compounds. Hydrophobic compounds readily partition into regular membrane lipid bilayers, and their transport through an aqueous protein channel is energetically unfavourable. Alternative transport models involving acquisition from the lipid bilayer by lateral diffusion have been proposed for hydrophobic substrates. So far, all transport proteins for which a lateral diffusion mechanism has been proposed function as efflux pumps. Here we present the first example of a lateral diffusion mechanism for the uptake of hydrophobic substrates by the Escherichia coli outer membrane long-chain fatty acid transporter FadL. A FadL mutant in which a lateral opening in the barrel wall is constricted, but which is otherwise structurally identical to wild-type FadL, does not transport substrates. A crystal structure of FadL from Pseudomonas aeruginosa shows that the opening in the wall of the beta-barrel is conserved and delineates a long, hydrophobic tunnel that could mediate substrate passage from the extracellular environment, through the polar lipopolysaccharide layer and, by means of the lateral opening in the barrel wall, into the lipid bilayer from where the substrate can diffuse into the periplasm. Because FadL homologues are found in pathogenic and biodegrading bacteria, our results have implications for combating bacterial infections and bioremediating xenobiotics in the environment.
2. Correction factors for wind tunnels of elliptic section with partly open and partly closed test section
NASA Technical Reports Server (NTRS)
Riegels, Fritz W
1951-01-01
Jet boundary corrections for partly open and partly closed elliptical wind tunnels for the cases of one and two solid wall segments are presented. Also presented are the combinations of model span and extent of the solid portion of the tunnel wall for which the average correction factor is zero.
3. Effect of cavity fore wall modifications in supersonic flow
NASA Astrophysics Data System (ADS)
Jeyakumar, S.; Yuvaraj, K. Arun; Jayaraman, K.; Cardona, F.; Sultan, M. T. H.
2016-10-01
Understanding the complex behaviour of the cavity flow is essential for the design of supersonic combustor. The characteristics of the axisymmetric aft ramp cavity with fore wall modification have been experimentally studied in a blow-down type supersonic flow facility. The facility consists of a conventional CD nozzle that issues a flow Mach number of 1.88 to a supersonic combustor of circular cross section, which is placed immediately downstream of the nozzle. The axisymmetric cavities are incorporated within the combustor. The cavities are of open type and their length is kept constant while their depth varies. The aft wall of the cavities is inclined with three ramp angles and the fore wall is provided with a constant fillet radius of 3 mm. The performance of the cavity is analysed based on wall static pressures, momentum flux distribution at the exit of the combustor and stagnation pressure loss across the combustor. The study reveals that fore wall fillet cavities provide less cavity drag and stagnation pressure loss for various aft ramp angles under identical operating conditions.
4. Open Babel: An open chemical toolbox
PubMed Central
2011-01-01
Background A frequent problem in computational modeling is the interconversion of chemical structures between different formats. While standard interchange formats exist (for example, Chemical Markup Language) and de facto standards have arisen (for example, SMILES format), the need to interconvert formats is a continuing problem due to the multitude of different application areas for chemistry data, differences in the data stored by different formats (0D versus 3D, for example), and competition between software along with a lack of vendor-neutral formats. Results We discuss, for the first time, Open Babel, an open-source chemical toolbox that speaks the many languages of chemical data. Open Babel version 2.3 interconverts over 110 formats. The need to represent such a wide variety of chemical and molecular data requires a library that implements a wide range of cheminformatics algorithms, from partial charge assignment and aromaticity detection, to bond order perception and canonicalization. We detail the implementation of Open Babel, describe key advances in the 2.3 release, and outline a variety of uses both in terms of software products and scientific research, including applications far beyond simple format interconversion. Conclusions Open Babel presents a solution to the proliferation of multiple chemical file formats. In addition, it provides a variety of useful utilities from conformer searching and 2D depiction, to filtering, batch conversion, and substructure and similarity searching. For developers, it can be used as a programming library to handle chemical data in areas such as organic chemistry, drug design, materials science, and computational chemistry. It is freely available under an open-source license from http://openbabel.org. PMID:21982300
5. Innovative Composite Wall System for Sheathing Masonry Walls
SciTech Connect
Wendt, Robert L.; Cavallo, James
1997-09-25
Existing Housing - Much of the older multifamily housing stock in the United States includes units in structures with uninsulated masonry walls. Included in this stock are two- and three-story walk-up apartments, larger apartment complexes, and public housing (both high- rise and townhouse). This older multifamily housing has seen years of heavy use that may have left the plaster wall marred or damaged. Long- term building settlement or movement may have cracked the plaster, sometimes severely. Moisture from invented kitchens and baths may have caused condensation on uninsulated exterior walls. At best this condensation has left stains on the paint or wallpaper. At worst it has supported mold and mildew growth, fouling the air and creating unhealthy living conditions. Deteriorating plaster and flaking paint also result from wet walls. The presence of flaking, lead-based paint in older (pre-1978) housing is a major public health concern. Children can suffer permanent mental handicaps and psychological disorders if they are subjected to elevated levels of lead, while adults can suffer hypertension and other maladies. Studies have found that, in some urban communities with older housing stocks, over 35% of children tested have elevated blood lead levels (Hastings, et al.: 1997). Nationally, nearly 22% of black, non-hispanic children living in pre-1946 housing were found to have elevated levels of lead in their blood (MWWR Article: February 21,1997). The deterioration of many of these walls is to the point that lead can freely enter the living space.
6. 28. Detail view of small triangular openings (perhaps for ventilation) ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
28. Detail view of small triangular openings (perhaps for ventilation) in top of S wall in center bay of N room of mill. - Hacienda Azurarera Santa Elena, Sugar Mill Ruins, 1.44 miles North of PR Route 2 Bridge Over Rio De La Plata, Toa Baja, Toa Baja Municipio, PR
7. 45. View of end bay of W elevation showing openings ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
45. View of end bay of W elevation showing openings in wall associated with sugar making process. - Hacienda Azurarera Santa Elena, Sugar Mill Ruins, 1.44 miles North of PR Route 2 Bridge Over Rio De La Plata, Toa Baja, Toa Baja Municipio, PR
8. NORTH AND WEST ELEVATIONS, SHOWING CA. 1960 OPEN STORAGE STRUCTURE, ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
NORTH AND WEST ELEVATIONS, SHOWING CA. 1960 OPEN STORAGE STRUCTURE, BRICK-WALLED NORTH PART, AND CORRUGATED-STEEL SOUTH PART, CAMERA FACING SOUTHEAST. - New Haven Rail Yard, Work Equipment Shop, Vicinity of Cedar & Lamberton Streets, New Haven, New Haven County, CT
9. 14. INTERIOR OF BEDROOM NUMBER TWO SHOWING OPEN DOORS TO ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
14. INTERIOR OF BEDROOM NUMBER TWO SHOWING OPEN DOORS TO WALK-IN CLOSETS, AND 1-LIGHT OVER 1-LIGHT SASH WINDOW ON NORTH WALL. VIEW TO WEST. - Rush Creek Hydroelectric System, Worker Cottage, Rush Creek, June Lake, Mono County, CA
10. 15. INTERIOR OF BEDROOM NUMBER TWO SHOWING OPEN DOOR TO ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
15. INTERIOR OF BEDROOM NUMBER TWO SHOWING OPEN DOOR TO VESTIBULE AT PHOTO RIGHT, AND 6-LIGHT OVER 1-LIGHT SASH WINDOW THROUGH SOUTH WALL AT PHOTO LEFT. VIEW TO SOUTH. - Rush Creek Hydroelectric System, Worker Cottage, Rush Creek, June Lake, Mono County, CA
11. 9. INTERIOR OF LIVING ROOM SHOWING OPEN PANEL DOOR TO ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
9. INTERIOR OF LIVING ROOM SHOWING OPEN PANEL DOOR TO BEDROOM NUMBER ONE AT PHOTO RIGHT, 6-LIGHT OVER 1 LIGHT SASH WINDOW ON REAR WALL AT PHOTO LEFT CENTER. FIREPLACE ORIGINALLY OCCUPIED SPACE UNDER ROUND HEATER VENT HOLE AT PHOTO LEFT. VIEW TO NORTHWEST. - Rush Creek Hydroelectric System, Worker Cottage, Rush Creek, June Lake, Mono County, CA
12. 10. INTERIOR OF LIVING ROOM SHOWING OPEN PANEL DOOR TO ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
10. INTERIOR OF LIVING ROOM SHOWING OPEN PANEL DOOR TO BEDROOM NUMBER ONE AT PHOTO CENTER, AND SECOND 6 LIGHT OVER 1-LIGHT SASH WINDOW ON REAR WALL AT PHOTO LEFT. VIEW TO NORTH. - Rush Creek Hydroelectric System, Worker Cottage, Rush Creek, June Lake, Mono County, CA
13. 22. INTERIOR OF BATHROOM NUMBER TWO LOOKING BACK THROUGH OPEN ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
22. INTERIOR OF BATHROOM NUMBER TWO LOOKING BACK THROUGH OPEN DOOR TO BEDROOM NUMBER THREE. MIRRORED MEDICINE CABINET FLANKED BY 1-LIGHT OVER 1 LIGHT SASH WINDOWS IN GROUPED ARRANGEMENT ON WEST WALL ABOVE SINK AT PHOTO LEFT. VIEW TO NORTHWEST. - Rush Creek Hydroelectric System, Clubhouse Cottage, Rush Creek, June Lake, Mono County, CA
14. One of the larger open spaces on the third floor. ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
One of the larger open spaces on the third floor. This space was used most often for drafting work and for general experimentation. Physical evidence on the ceiling indicates existence of partition walls for smaller rooms, but no photographic or documentary evidence has surfaced to verify this. - Thomas A. Edison Laboratories, Building No. 5, Main Street & Lakeside Avenue, West Orange, Essex County, NJ
15. View looking south out the door opening from the south ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
View looking south out the door opening from the south side of the rotunda extension onto the "dog house" or vestibule positioned where the west Verandah of the south wing turns ninety degrees and continues along the south wall of the central pavilion. - U. S. Naval Asylum, Biddle Hall, Gray's Ferry Avenue, Philadelphia, Philadelphia County, PA
16. 3. DETAIL OF NORTHEAST CORNER; OPENING AT TOP WAS INTAKE ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
3. DETAIL OF NORTHEAST CORNER; OPENING AT TOP WAS INTAKE FOR CATTLE; CANTILEVERED HOG RUN (BUILDING 147) OBSCURES A PORTION OF THE BEEF KILL'S ORIGINAL GLASS BLOCK WALLS - Rath Packing Company, Beef Killing Building, Sycamore Street between Elm & Eighteenth Streets, Waterloo, Black Hawk County, IA
17. {open_quotes}Car Talk{close_quotes}: An autopsy
SciTech Connect
1996-11-01
{open_quotes}Car Talk{close_quotes} - the Clinton administrations vehicle for reducing greenhouse gas emissions from passenger cars and light-duty trucks-hit the wall amid charges and countercharges hurled by its frustrated participants. A careful post-mortem reveals lessons that can redeem the process for dealing with future public policy controversies.
18. 17. VIEW TO EAST SHOWING ONE OF THE OPENINGS IN ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
17. VIEW TO EAST SHOWING ONE OF THE OPENINGS IN THE SECOND FLOOR EAST WALL THROUGH WHICH A CONVEYOR ONCE PASSED FOR MOVING BODY PANELS TO AND FROM THE SECOND FLOOR. - Rosie the Riveter National Historical Park, Ford Assembly Plant, 1400 Harbour Way South, Richmond, Contra Costa County, CA
19. 5. EXTERIOR OF SOUTH END OF HOUSE SHOWING OPEN DOOR ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
5. EXTERIOR OF SOUTH END OF HOUSE SHOWING OPEN DOOR TO BASEMENT BELOW KITCHEN, ORIGINAL PAIRED WOODFRAMED SLIDING-GLASS WINDOWS ON KITCHEN WALL AND 1LIGHT OVER 1-LIGHT DOUBLE-HUNG WINDOW ON STORM PORCH ADDITION. VIEW TO WEST. - Rush Creek Hydroelectric System, Clubhouse Cottage, Rush Creek, June Lake, Mono County, CA
20. 18. VIEW TO EAST, DETAIL OF OPENING THROUGH THE SECOND ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
18. VIEW TO EAST, DETAIL OF OPENING THROUGH THE SECOND FLOOR EAST WALL SHOWING CONVEYOR FOR MOVING MATERIAL TO THE SECOND FLOOR. (NOTE: THIS IS NOT AN ORIGINAL CONVEYOR FOR MOVING BODY PARTS). - Rosie the Riveter National Historical Park, Ford Assembly Plant, 1400 Harbour Way South, Richmond, Contra Costa County, CA
1. Wall thickness effect on the resistive wall mode stability in toroidal plasmas
SciTech Connect
Zheng, L.-J.; Kotschenreuther, M.T.
2005-07-15
The effect of finite wall thickness on the stability of n=1 resistive wall modes in toroidal plasmas is investigated. A fusion reactor-relevant configuration is examined. The investigation employs a novel ideal-magnetohydrodynamics adaptive shooting code for axisymmetric plasmas, extended to take into account the wall thickness. Although finite wall thickness generally reduces the growth rate of the resistive wall modes, no contribution to stabilization is found to be made by the portion of the wall that is located beyond the critical position for perfectly conducting wall stabilization. Thus, when the inner side of the wall lies near the critical wall position, the scaling of the growth rate versus wall thickness in the realistic thick-wall calculation is significantly different from that of the usual thin-wall theory. The thin-wall estimate is relevant only when the wall is brought very close to the plasma and is not too thick.
2. Effects of the flexibility of the arterial wall on the wall shear stresses and wall tension in Abdominal Aortic Aneurysms.
NASA Astrophysics Data System (ADS)
Salsac, Anne-Virginie; Fernandez, Miguel; Chomaz, Jean-Marc
2005-11-01
As an abdominal aortic aneurysm develops, large changes occur in the composition and structure of the arterial wall, which result in its stiffening. So far, most studies, whether experimental or numerical, have been conducted assuming the walls to be rigid. A numerical simulation of the fluid structure interactions is performed in different models of aneurysms in order to analyze the effects that the wall compliance might have on the flow topology. Both symmetric and non-symmetric models of aneurysms are considered, all idealistic in shape. The wall mechanical properties are varied in order to simulate the progressive stiffening of the walls. The spatial and temporal distributions of wall tension are calculated for the different values of the wall elasticity and compared to the results for the rigid walls. In the case of rigid walls, the calculation of the wall shear stresses and pressure compare very well with experimental results.
3. Opening and Closing in Open Systems.
ERIC Educational Resources Information Center
Klapp, Orrin E.
In open information systems, such as in the case of human interchange with the self and the environment, input quantities have no upper limits. The human information utilization system, however, is psychologically and behaviorally unable to accept ever increasing loads of information. Because of this apparent fact, human information systems should…
4. Opening Up Access to Open Access
ERIC Educational Resources Information Center
Singer, Ross
2008-01-01
As the corpus of gray literature grows and the price of serials rises, it becomes increasingly important to explore ways to integrate the free and open Web seamlessly into one's collections. Users, after all, are discovering these materials all the time via sites such as Google Scholar and Scirus or by searching arXiv.org or CiteSeer directly.…
5. Investigating the Effect of Carbon Nanotube Diameter and Wall Number in Carbon Nanotube/Silicon Heterojunction Solar Cells
PubMed Central
Grace, Tom; Yu, LePing; Gibson, Christopher; Tune, Daniel; Alturaif, Huda; Al Othman, Zeid; Shapter, Joseph
2016-01-01
Suspensions of single-walled, double-walled and multi-walled carbon nanotubes (CNTs) were generated in the same solvent at similar concentrations. Films were fabricated from these suspensions and used in carbon nanotube/silicon heterojunction solar cells and their properties were compared with reference to the number of walls in the nanotube samples. It was found that single-walled nanotubes generally produced more favorable results; however, the double and multi-walled nanotube films used in this study yielded cells with higher open circuit voltages. It was also determined that post fabrication treatments applied to the nanotube films have a lesser effect on multi-walled nanotubes than on the other two types. PMID:28344309
6. Isolation of the Cell Wall.
PubMed
Canut, Hervé; Albenne, Cécile; Jamet, Elisabeth
2017-01-01
This chapter describes a method allowing the purification of the cell wall for studying both polysaccharides and proteins. The plant primary cell wall is mainly composed of polysaccharides (90-95 % in mass) and of proteins (5-10 %). At the end of growth, specialized cells may synthesize a lignified secondary wall composed of polysaccharides (about 65 %) and lignin (about 35 %). Due to its composition, the cell wall is the cellular compartment having the highest density and this property is used for its purification. It plays critical roles during plant development and in response to environmental constraints. It is largely used in the food and textile industries as well as for the production of bioenergy. All these characteristics and uses explain why its study as a true cell compartment is of high interest. The proposed method of purification can be used for large amount of material but can also be downscaled to 500 mg of fresh material. Tools for checking the quality of the cell wall preparation, such as protein analysis and microscopy observation, are also provided.
7. MHD Electrode and wall constructions
DOEpatents
Way, Stewart; Lempert, Joseph
1984-01-01
Electrode and wall constructions for the walls of a channel transmitting the hot plasma in a magnetohydrodynamic generator. The electrodes and walls are made of a plurality of similar modules which are spaced from one another along the channel. The electrodes can be metallic or ceramic, and each module includes one or more electrodes which are exposed to the plasma and a metallic cooling bar which is spaced from the plasma and which has passages through which a cooling fluid flows to remove heat transmitted from the electrode to the cooling bar. Each electrode module is spaced from and electrically insulated from each adjacent module while interconnected by the cooling fluid which serially flows among selected modules. A wall module includes an electrically insulating ceramic body exposed to the plasma and affixed, preferably by mechanical clips or by brazing, to a metallic cooling bar spaced from the plasma and having cooling fluid passages. Each wall module is, similar to the electrode modules, electrically insulated from the adjacent modules and serially interconnected to other modules by the cooling fluid.
8. Functional domain walls in multiferroics.
PubMed
Meier, Dennis
2015-11-25
During the last decade a wide variety of novel and fascinating correlation phenomena has been discovered at domain walls in multiferroic bulk systems, ranging from unusual electronic conductance to inseparably entangled spin and charge degrees of freedom. The domain walls represent quasi-2D functional objects that can be induced, positioned, and erased on demand, bearing considerable technological potential for future nanoelectronics. Most of the challenges that remain to be solved before turning related device paradigms into reality, however, still fall in the field of fundamental condensed matter physics and materials science. In this topical review seminal experimental findings gained on electric and magnetic domain walls in multiferroic bulk materials are addressed. A special focus is put on the physical properties that emerge at so-called charged domain walls and the added functionality that arises from coexisting magnetic order. The research presented in this review highlights that we are just entering a whole new world of intriguing nanoscale physics that is yet to be explored in all its details. The goal is to draw attention to the persistent challenges and identify future key directions for the research on functional domain walls in multiferroics.
9. Turbine airfoil with outer wall thickness indicators
DOEpatents
Marra, John J; James, Allister W; Merrill, Gary B
2013-08-06
A turbine airfoil usable in a turbine engine and including a depth indicator for determining outer wall blade thickness. The airfoil may include an outer wall having a plurality of grooves in the outer surface of the outer wall. The grooves may have a depth that represents a desired outer surface and wall thickness of the outer wall. The material forming an outer surface of the outer wall may be removed to be flush with an innermost point in each groove, thereby reducing the wall thickness and increasing efficiency. The plurality of grooves may be positioned in a radially outer region of the airfoil proximate to the tip.
10. The DEMO wall load challenge
NASA Astrophysics Data System (ADS)
Wenninger, R.; Albanese, R.; Ambrosino, R.; Arbeiter, F.; Aubert, J.; Bachmann, C.; Barbato, L.; Barrett, T.; Beckers, M.; Biel, W.; Boccaccini, L.; Carralero, D.; Coster, D.; Eich, T.; Fasoli, A.; Federici, G.; Firdaouss, M.; Graves, J.; Horacek, J.; Kovari, M.; Lanthaler, S.; Loschiavo, V.; Lowry, C.; Lux, H.; Maddaluno, G.; Maviglia, F.; Mitteau, R.; Neu, R.; Pfefferle, D.; Schmid, K.; Siccinio, M.; Sieglin, B.; Silva, C.; Snicker, A.; Subba, F.; Varje, J.; Zohm, H.
2017-04-01
11. Debonding Stress Concentrations in a Pressurized Lobed Sandwich-Walled Generic Cryogenic Tank
NASA Technical Reports Server (NTRS)
Ko, William L.
2004-01-01
A finite-element stress analysis has been conducted on a lobed composite sandwich tank subjected to internal pressure and cryogenic cooling. The lobed geometry consists of two obtuse circular walls joined together with a common flat wall. Under internal pressure and cryogenic cooling, this type of lobed tank wall will experience open-mode (a process in which the honeycomb is stretched in the depth direction) and shear stress concentrations at the junctures where curved wall changes into flat wall (known as a curve-flat juncture). Open-mode and shear stress concentrations occur in the honeycomb core at the curve-flat junctures and could cause debonding failure. The levels of contributions from internal pressure and temperature loading to the open-mode and shear debonding failure are compared. The lobed fuel tank with honeycomb sandwich walls has been found to be a structurally unsound geometry because of very low debonding failure strengths. The debonding failure problem could be eliminated if the honeycomb core at the curve-flat juncture is replaced with a solid core.
12. Numerical and experimental study of transient natural convection in an inclined wall cavity
SciTech Connect
Rojas, J.; Avila, F.
1995-09-01
Transient natural convection in an open cavity with one inclined wall is analyzed both numerically and experimentally. The fluid and the cavity are in thermal equilibrium at the onset of the experiment. The inclined wall is heated in such a way that the wall temperature increases uniformly according to an hyperbolic tangent function. The transport equations are solved using a 2-D transient model with a non-orthogonal body fitted coordinate system and an exponential grid distribution for better spatial resolution near the inclined wall. Measurements of velocity and temperature are performed at some key points of the boundary layer and intrusion layer. The fluid motion and heat transfer are analyzed from the time at which heat is applied though the inclined wall to the time at which its effect is detected at the opposite sidewall. The main patterns of the fluid flow and heat transfer are well predicted as comparisons against experimental results indicate.
13. The forced sound transmission of finite single leaf walls using a variational technique.
PubMed
Brunskog, Jonas
2012-09-01
The single wall is the simplest element of concern in building acoustics, but there still remain some open questions regarding the sound insulation of this simple case. The two main reasons for this are the effects on the excitation and sound radiation of the wall when it has a finite size, and the fact that the wave field in the wall is consisting of two types of waves, namely forced waves due to the exciting acoustic field, and free bending waves due to reflections in the boundary. The aim of the present paper is to derive simple analytical formulas for the forced part of the airborne sound insulation of a single homogeneous wall of finite size, using a variational technique based on the integral-differential equation of the fluid loaded wall. The so derived formulas are valid in the entire audible frequency range. The results are compared with full numerical calculations, measurements and alternative theory, with reasonable agreement.
14. Variability of cell wall polysaccharides composition and hemicellulose enzymatic profile in an apple progeny.
PubMed
Galvez-Lopez, D; Laurens, F; Quéméner, B; Lahaye, M
2011-12-01
The genetic variability of apple cell walls polysaccharides chemical composition and structure was assessed in a progeny of 141 individuals harvested over 2 years. The variability of the hemicelluloses oligosaccharides released by glucanase was analyzed by MALDI-TOF MS. The genetic contribution was distinguished from harvest year as well as from parental crossing patterns and scab resistance selection. Results showed that harvest year had a major impact on cell wall polysaccharide composition and structure. Within each harvest, genetic effect impact more significantly cell wall polysaccharide chemistry than does reciprocal crossing or early scab selection. Uronic acids, glucose, galactose and xylose contents as well as some glucomannan and xyloglucan structures have a high heritability. This first cell wall chemotyping of an apple progeny opens the way for future searches of genetic markers for the chemical variability of cell wall polysaccharides.
15. Egress door opening assister
DOEpatents
Allison, Thomas L.
2015-10-06
A door opening spring assistance apparatus is set forth that will automatically apply a door opening assistance force using a combination of rods and coil springs. The release of the rods by the coil springs reduces the force required to set the door in motion.
16. Open Rotor Aeroacoustic Modelling
NASA Technical Reports Server (NTRS)
Envia, Edmane
2012-01-01
Owing to their inherent fuel efficiency, there is renewed interest in developing open rotor propulsion systems that are both efficient and quiet. The major contributor to the overall noise of an open rotor system is the propulsor noise, which is produced as a result of the interaction of the airstream with the counter-rotating blades. As such, robust aeroacoustic prediction methods are an essential ingredient in any approach to designing low-noise open rotor systems. To that end, an effort has been underway at NASA to assess current open rotor noise prediction tools and develop new capabilities. Under this effort, high-fidelity aerodynamic simulations of a benchmark open rotor blade set were carried out and used to make noise predictions via existing NASA open rotor noise prediction codes. The results have been compared with the aerodynamic and acoustic data that were acquired for this benchmark open rotor blade set. The emphasis of this paper is on providing a summary of recent results from a NASA Glenn effort to validate an in-house open noise prediction code called LINPROP which is based on a high-blade-count asymptotic approximation to the Ffowcs-Williams Hawkings Equation. The results suggest that while predicting the absolute levels may be difficult, the noise trends are reasonably well predicted by this approach.
17. Open Source Molecular Modeling
PubMed Central
Pirhadi, Somayeh; Sunseri, Jocelyn; Koes, David Ryan
2016-01-01
The success of molecular modeling and computational chemistry efforts are, by definition, dependent on quality software applications. Open source software development provides many advantages to users of modeling applications, not the least of which is that the software is free and completely extendable. In this review we categorize, enumerate, and describe available open source software packages for molecular modeling and computational chemistry. PMID:27631126
18. Opening up Education: The Collective Advancement of Education through Open Technology, Open Content, and Open Knowledge
ERIC Educational Resources Information Center
Iiyoshi, Toru, Ed.; Kumar, M. S. Vijay, Ed.
2008-01-01
Given the abundance of open education initiatives that aim to make educational assets freely available online, the time seems ripe to explore the potential of open education to transform the economics and ecology of education. Despite the diversity of tools and resources already available--from well-packaged course materials to simple games, for…
19. Guidelines on Open Expression.
ERIC Educational Resources Information Center
These Guidelines on open expression at the University of Pennsylvania include: (1) a statement of principles, expressing support for freedom of thought, inquiry, speech and lawful assembly, and for the need to ensure continuing openness and effectiveness of channels of communication; (2) a description of the newly created Committee on Open…
20. Open Source Vision
ERIC Educational Resources Information Center
Villano, Matt
2006-01-01
Increasingly, colleges and universities are turning to open source as a way to meet their technology infrastructure and application needs. Open source has changed life for visionary CIOs and their campus communities nationwide. The author discusses what these technologists see as the benefits--and the considerations.
1. Creating Open Source Conversation
ERIC Educational Resources Information Center
Sheehan, Kate
2009-01-01
Darien Library, where the author serves as head of knowledge and learning services, launched a new website on September 1, 2008. The website is built with Drupal, an open source content management system (CMS). In this article, the author describes how she and her colleagues overhauled the library's website to provide an open source content…
2. The Argument for Open
ERIC Educational Resources Information Center
Byrd, Rob
2008-01-01
Is open source business intelligence (OS BI) software ready for prime time? The author thoroughly investigated each of three OS BI toolsets--Pentaho BI Suite, Jaspersoft BI Suite, and Talend Open Studio--by installing the OS BI tools himself, by interviewing technologists at academic institutions who had implemented these OS BI solutions, and by…
3. Open Rotor Aeroacoustic Modeling
NASA Technical Reports Server (NTRS)
Envia, Edmane
2012-01-01
Owing to their inherent fuel efficiency, there is renewed interest in developing open rotor propulsion systems that are both efficient and quiet. The major contributor to the overall noise of an open rotor system is the propulsor noise, which is produced as a result of the interaction of the airstream with the counter-rotating blades. As such, robust aeroacoustic prediction methods are an essential ingredient in any approach to designing low-noise open rotor systems. To that end, an effort has been underway at NASA to assess current open rotor noise prediction tools and develop new capabilities. Under this effort, high-fidelity aerodynamic simulations of a benchmark open rotor blade set were carried out and used to make noise predictions via existing NASA open rotor noise prediction codes. The results have been compared with the aerodynamic and acoustic data that were acquired for this benchmark open rotor blade set. The emphasis of this paper is on providing a summary of recent results from a NASA Glenn effort to validate an in-house open noise prediction code called LINPROP which is based on a high-blade-count asymptotic approximation to the Ffowcs-Williams Hawkings Equation. The results suggest that while predicting the absolute levels may be difficult, the noise trends are reasonably well predicted by this approach.
4. Opening a New Door
ERIC Educational Resources Information Center
Waters, John K.
2007-01-01
A growing number of K-12 districts are taking the open source plunge, both to cope with tight budgets and to escape proprietary vendor lock-in and expensive upgrade cycles. With the potential for cost savings and a growing number of educational applications, open source software is proving to be an effective alternative for schools willing to make…
5. OpenSearch Status
NASA Technical Reports Server (NTRS)
Newman, Doug; Silva, Sam; Mitchell, Andrew
2016-01-01
We will present an overview of our OpenSearch efforts over the past 6 months. We will discuss our Best Practices and those of CEOS concentrating on the compatibility issues between the two. We will also discuss the state of earth data OpenSearch implementations and their adherence to the standards, extensions and best practices available.
6. Triggered plasma opening switch
DOEpatents
Mendel, Clifford W.
1988-01-01
A triggerable opening switch for a very high voltage and current pulse includes a transmission line extending from a source to a load and having an intermediate switch section including a plasma for conducting electrons between transmission line conductors and a magnetic field for breaking the plasma conduction path and magnetically insulating the electrons when it is desired to open the switch.
7. Sporothrix schenckii Cell Wall Peptidorhamnomannans
PubMed Central
Lopes-Bezerra, Leila M.
2011-01-01
This mini-review article is dedicated to clarifying certain important biochemical aspects of Sporothrix schenckii cell wall peptidorhamnomannans. Cell wall components involved in the host interaction such as antigens as well as a gp70 adhesin are important molecules present on the surface of the yeast parasitic phase. Other structural glycoconjugates present on the fungus cell surface are also described here. Knowledge of the fine structure of carbohydrate epitopes expressed on the surface in both morphological phases of S. schenckii permitted the development of non-invasive immunochemical methods to diagnose human and feline sporotrichosis. PMID:22203817
8. Gullies in Terraced Crater Wall
NASA Technical Reports Server (NTRS)
2003-01-01
MGS MOC Release No. MOC2-375, 29 May 2003
Gullies--possibly formed by a liquid such as water in the recent martian past--formed at two different levels in the walls of a meteor impact crater near 36.2oS, 185.5oW. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies in the upper crater wall (top of the image) and emergent from the slope of a lower terrace (bottom of the image). Sunlight illuminates the scene from the upper left.
9. Wall Interference in Wind Tunnels
DTIC Science & Technology
1982-09-01
d’un d £ faut d’ßtendue des signatures. Sp^cialeinent dans le cas de la correction d’incidence, la pondäration des ecarts de Kp entre les deux parois, de...für Stromungsmechanik der Tech. Univers. Bienroder Weg 3 D -3300 Braunschweig — Germany MrL.H.Ohman Head, High Speed Aerodynamics Lab. National...CORRECTIONS IM ’. • SOLID-WALL TUNNELS FROM MEASUREMENTS OF STATIC PRESSURE AT THE WALLS j t by t P. R. Ashill and D . J. Weeks Aerodynamics
10. Open-closed switching of synthetic tubular pores
NASA Astrophysics Data System (ADS)
Kim, Yongju; Kang, Jiheong; Shen, Bowen; Wang, Yanqiu; He, Ying; Lee, Myongsoo
2015-10-01
While encouraging progress has been made on switchable nanopores to mimic biological channels and pores, it remains a great challenge to realize long tubular pores with a dynamic open-closed motion. Here we report μm-long, dynamic tubular pores that undergo rapid switching between open and closed states in response to a thermal signal in water. The tubular walls consist of laterally associated primary fibrils stacked from disc-shaped molecules in which the discs readily tilt by means of thermally regulated dehydration of the oligoether chains placed on the wall surfaces. Notably, this pore switching mediates a controlled water-pumping catalytic action for the dehydrative cyclization of adenosine monophosphate to produce metabolically active cyclic adenosine monophosphate. We believe that our work may allow the creation of a variety of dynamic pore structures with complex functions arising from open-closed motion.
11. Stability of open pathways
PubMed Central
Flach, Edward H.; Schnell, Santiago
2010-01-01
We consider the steady state of an open biochemical pathway, with controlled flow. Previously we have shown that the steady state of open enzyme catalysed reactions may be unstable, which discourages the application of the quasi-steady-state approximation (QSSA) (IEE Proc. Syst. Biol. 153 (2006) 187). Here we examine basic open biochemical pathway structures, to see the stability of their steady states. Following De Leenheer et al. (J. Math. Chem. 41 (2007) 295), we employ the Gershgorin circle theorem, which elegantly assesses stability. This is the key tool for our analysis. Once we have the linear stability matrix laid out in a suitable form, the application of the method is straightforward. We find that in open biochemical pathways, simple chains, branches and loops always have stable steady states. We conclude that simple open pathways are stable. PMID:20875827
12. Acoustic modeling of a three-dimensional rectangular opened enclosure coupled with a semi-infinite exterior field at the baffled opening.
PubMed
Jin, Guoyong; Shi, Shuangxia; Liu, Zhigang
2016-11-01
A modeling method is proposed for the acoustic analysis of a three-dimensional (3D) rectangular opened enclosure coupled with a semi-infinite exterior field by a rectangular opening of arbitrary size, and with general wall impedance. In contrast to existing modeling methods that solve the differential equations, the energy principle in combination with a 3D modified Fourier cosine series is employed in the present method for the modeling of this system. Under this theoretical framework, the effect of an opening in the wall of a rectangular enclosure is taken into account via the work done by the sound pressure acting on the opening between the finite enclosure and exterior domain. The sound pressure inside the opened enclosure is expressed as the combination of a 3D trigonometric cosine series and one supplementary 2D expansion introduced to ensure uniform convergence of the solution over the entire solution domain including opening boundary. The acoustic responses of the opened enclosure are obtained based on the energy expressions for the enclosure system. The effectiveness and reliability of the current method are checked against the results obtained by the boundary element method and experimental results, and excellent agreement is achieved. The effects of sizes and positions of the opening and wall impedance on the acoustic behaviors of opened enclosure system are investigated.
13. Recovery after abdominal wall reconstruction.
PubMed
Jensen, Kristian Kiim
2017-03-01
Incisional hernia is a common long-term complication to abdominal surgery, occurring in more than 20% of all patients. Some of these hernias become giant and affect patients in several ways. This patient group often experiences pain, decreased perceived body image, and loss of physical function, which results in a need for surgical repair of the giant hernia, known as abdominal wall reconstruction. In the current thesis, patients with a giant hernia were examined to achieve a better understanding of their physical and psychological function before and after abdominal wall reconstruction. Study I was a systematic review of the existing standardized methods for assessing quality of life after incisional hernia repair. After a systematic search in the electronic databases Embase and PubMed, a total of 26 studies using standardized measures for assessment of quality of life after incisional hernia repair were found. The most commonly used questionnaire was the generic Short-Form 36, which assesses overall health-related quality of life, addressing both physical and mental health. The second-most common questionnaire was the Carolinas Comfort Scale, which is a disease specific questionnaire addressing pain, movement limitation and mesh sensation in relation to a current or previous hernia. In total, eight different questionnaires were used at varying time points in the 26 studies. In conclusion, standardization of timing and method of quality of life assessment after incisional hernia repair was lacking. Study II was a case-control study of the effects of an enhanced recovery after surgery pathway for patients undergoing abdominal wall reconstruction for a giant hernia. Sixteen consecutive patients were included prospectively after the implementation of a new enhanced recovery after surgery pathway at the Digestive Disease Center, Bispebjerg Hospital, and compared to a control group of 16 patients included retrospectively in the period immediately prior to the
14. Thermal breaking systems for metal stud walls -- Can metal stud walls perform as well as wood stud walls
SciTech Connect
Kosny, J.; Christian, J.E.; Desjarlais, A.O.
1997-12-31
Metal stud wall systems for residential buildings are gaining in popularity. Strong thermal bridges caused by highly conductive metal studs degrade the thermal performance of such walls. Several wall configurations have been developed to improve their thermal performance. The authors tried to evaluate some of these wall systems. The thermal performance of metal stud walls is frequently compared with that of wood stud walls. A reduction of the in-cavity R-value caused by the wood studs is about 10% in wood stud walls. In metal stud walls, thermal bridges generated by the metal components reduce their thermal performance by up to 55%. Today, metal stud walls are believed to be considerably less thermally effective than similar systems made of wood because steel has much higher thermal conductivity than wood. Relatively high R-values may be achieved by installing insulating sheathing, which is now widely recommended as the remedy for weak thermal performance of metal stud walls. A series of promising metal stud wall configurations was analyzed. Some of these walls were designed and tested by the authors, some were tested in other laboratories, and some were developed and forgotten a long time ago. Several types of thermal breaking systems were used in these walls. Two- and three-dimensional finite-difference computer simulations were used to analyze 20 metal stud wall configurations. Also, a series of hot-box tests were conducted on several of these walls. Test results for 22 additional metal stud walls were analyzed. Most of these walls contained conventional metal studs. Commonly used fiberglass and EPS were used as insulation materials. The most promising metal stud wall configurations have reductions in the center-of-cavity R-values of less than 20%.
15. Ascending aortic wall cohesion: comparison of bicuspid and tricuspid valves.
PubMed
Benedik, Jaroslav; Pilarczyk, Kevin; Wendt, Daniel; Indruch, Jiri; Flek, Radek; Tsagakis, Konstantinos; Alaeddine, Savvas; Jakob, Heinz
2012-01-01
Objectives. Bicuspid aortic valve (AV) represents the most common form of congenital AV malformation, which is frequently associated with pathologies of the ascending aorta. We compared the mechanical properties of the aortic wall between patients with bicuspid and tricuspid AV using a new custom-made device mimicking transversal aortic wall shear stress. Methods. Between 03/2010 and 07/2011, 190 consecutive patients undergoing open aortic valve replacement at our institution were prospectively enrolled, presenting either with a bicuspid (group 1, n = 44) or a tricuspid (group 2, n = 146) AV. Aortic wall specimen were examined with the "dissectometer" resulting in nine specific aortic-wall parameters derived from tensile strength curves (TSC). Results. Patients with a bicuspid AV showed significantly more calcified valves (43.2% versus 15.8%, P < 0.001), and a significantly thinner aortic wall (2.04 ± 0.42 mm versus 2.24 ± 0.41 mm, P = 0.008). Transesophageal echocardiography diameters (annulus, aortic sinuses, and sinotubular junction) were significantly larger in the bicuspid group (P = 0.003, P = 0.02, P = 0.01). We found no difference in the aortic wall cohesion between both groups as revealed by shear stress testing (P = 0.72, P = 0.40, P = 0.41). Conclusion. We observed no differences of TSC in patients presenting with tricuspid or bicuspid AVs. These results may allow us to assume that the morphology of the AV and the pathology of the ascending aorta are independent.
16. Wall-layer model for LES with massive separation
NASA Astrophysics Data System (ADS)
Fakhari, Ahmad; Armenio, Vincenzo; Roman, Federico
2016-11-01
Currently, Wall Functions (WF) work well under specific conditions, mostly exhibit drawbacks specially in flows with separation beyond curvatures. In this work, we propose a more general WF which works well in attached and detached flows, in presence and absence of Immersed Boundaries (IB). First we modified an equilibrium stress WF for boundary-fitted geometry making dynamic the computation of the k (von Karman constant) of the log-law; the model was first applied to a periodic open channel flow, and then to the flow over a 2D single hill using uniform coarse grids; the model captured separation with reasonable accuracy. Thereafter IB Method by Roman et al. was improved to avoid momentum loss at the interface between the fluid-solid regions. This required calibration of interfacial eddy viscosity; also a random stochastic forcing was used in wall-normal direction to increase Reynolds stresses and improve mean velocity profile. Finally, to reproduce flow separation, a simplified boundary layer equation was applied to construct velocity at near wall computational nodes. The new scheme was tested on the 2D single hill and periodic hills applying Cartesian and curvilinear grids; good agreement with references was obtained with reduction in cost and complexity. Financial support from project COSMO "CFD open source per opera morta" PAR FSC 2007-2013, Friuli Venezia Giulia.
17. Reconstruction of chest wall defects.
PubMed
Hasse, J
1991-12-01
A series of 61 consecutive procedures of chest wall resection and reconstruction in 58 patients during the period between August, 1986 and December, 1990 is reported. The ages ranged between 6-77 years. The chest wall resection was indicated for malignant affections in 54 cases. Among these, there were 24 patients with bronchial carcinoma invading the chest wall, 17 patients with primary or metastatic sarcoma, 11 patients with recurrent breast cancer and 3 with cancer metastases of varying origin. Pulmonary resection included pneumonectomy in 8 cases, lobectomy in 19, segmental and wedge resections in 26. In the majority of resections, the reconstruction was accomplished without implants. In cases with full thickness removal of the chest wall, the plane of the rib cage and/or the sternum was reconstructed using Vicryl mesh (n = 7), PTFE soft tissue patch (n = 11), marlex-mesh (n = 1), or methyl-methacrylate (n = 3). There was one case of hospital mortality, 6 weeks postoperatively, due to neurological failure from an independent preoperatively undiagnosed brain tumor. There were 4 reoperations: one early and one late (4 months) infection, one case of limited superficial necrosis of a flap and one with chronic lymphous drainage from a large myocutaneous flap. In no instance was primary postoperative ventilation therapy necessary. Mechanical ventilation was instituted only on day 8 in the patient who accounts for the mortality in this series. In the presence of primary infection, the greater omentum was used for the restoration of the integument.
18. Tube-Wall Thickness Detector
NASA Technical Reports Server (NTRS)
Kleint, R. E.; Baily, R. D.
1985-01-01
Eddy-current measurements detect wear of thin walls (0.01 in) (0.25 mm) in small diameter (0.19 in) (5 mm) heat exchanger tubing. Flexible durable thin rod inserts eddy-current coil into the heatexchanger tube.
19. Statistical characteristics of simulated walls
NASA Astrophysics Data System (ADS)
Demiański, M.; Doroshkevich, A. G.; Müller, V.; Turchaninov, V.
2000-11-01
The large-scale matter distribution in three different simulations of CDM models is investigated and compared with corresponding results of the Zel'dovich theory of non-linear gravitational instability. We show that the basic characteristics of wall-like structure elements are well described by this theory, and that they can be expressed by the cosmological parameters and a few spectral moments of the perturbation spectrum. Therefore the characteristics of such elements provide reasonable estimates of these parameters. We show that the compressed matter is relaxed and gravitationally confined and manifests itself in the existence of walls as (quasi-)stationary structure elements with a lifetime restricted by their disruption into high-density clouds. The matter distribution is investigated in both real and redshift spaces. In both cases almost the same particles form the walls, and we estimate differences in corresponding wall characteristics. The same methods are applied to several mock catalogues of galaxies', which allows us to characterize a large-scale bias between the spatial distribution of dark matter and of simulated galaxies'.
20. Designing a Sound Reducing Wall
ERIC Educational Resources Information Center
Erk, Kendra; Lumkes, John; Shambach, Jill; Braile, Larry; Brickler, Anne; Matthys, Anna
2015-01-01
Acoustical engineers use their knowledge of sound to design quiet environments (e.g., classrooms and libraries) as well as to design environments that are supposed to be loud (e.g., concert halls and football stadiums). They also design sound barriers, such as the walls along busy roadways that decrease the traffic noise heard by people in…
1. Mirror, Mirror, on the Wall.
ERIC Educational Resources Information Center
Flowers, Jim; Rose, M. Annette
1998-01-01
Students use tables of anthropometric data, their own measurements, underlying principles of physics, and math to solve a problem. The problem is to determine the height of a wall mirror, and where to mount it, so that 90% of the clientele can view their entire length without stretching or bending. (Author)
2. Wary Eyes Monitoring Wall Street
ERIC Educational Resources Information Center
Jacobson, Linda
2008-01-01
School business officials kept a close watch on the financial markets this week--and on district investment portfolios and teacher-retirement funds--as stock prices gyrated and once-sound institutions got government bailouts or crumbled into bankruptcy. While financial observers said it was too soon to predict how Wall Street's upheaval might…
3. 9. INTERIOR OF LIVING ROOM SHOWING OPEN 6LIGHT FRONT ENTRY ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
9. INTERIOR OF LIVING ROOM SHOWING OPEN 6-LIGHT FRONT ENTRY DOOR, OPEN PANEL DOOR TO BEDROOM NUMBER ONE, AND 6-LIGHT OVER 1-LIGHT SASH WINDOW ON REAR WALL AT PHOTO LEFT CENTER. FIREPLACE ORIGINALLY OCCUPIED SPACE UNDER ROUND HEATER VENT HOLE AT PHOTO LEFT. VIEW TO WEST. - Rush Creek Hydroelectric System, Worker Cottage, Rush Creek, June Lake, Mono County, CA
4. Cell wall construction in Saccharomyces cerevisiae.
PubMed
Klis, Frans M; Boorsma, Andre; De Groot, Piet W J
2006-02-01
In this review, we discuss new insights in cell wall architecture and cell wall construction in the ascomycetous yeast Saccharomyces cerevisiae. Transcriptional profiling studies combined with biochemical work have provided ample evidence that the cell wall is a highly adaptable organelle. In particular, the protein population that is anchored to the stress-bearing polysaccharides of the cell wall, and forms the interface with the outside world, is highly diverse. This diversity is believed to play an important role in adaptation of the cell to environmental conditions, in growth mode and in survival. Cell wall construction is tightly controlled and strictly coordinated with progression of the cell cycle. This is reflected in the usage of specific cell wall proteins during consecutive phases of the cell cycle and in the recent discovery of a cell wall integrity checkpoint. When the cell is challenged with stress conditions that affect the cell wall, a specific transcriptional response is observed that includes the general stress response, the cell wall integrity pathway and the calcineurin pathway. This salvage mechanism includes increased expression of putative cell wall assemblases and some potential cross-linking cell wall proteins, and crucial changes in cell wall architecture. We discuss some more enzymes involved in cell wall construction and also potential inhibitors of these enzymes. Finally, we use both biochemical and genomic data to infer that the architectural principles used by S. cerevisiae to build its cell wall are also used by many other ascomycetous yeasts and also by some mycelial ascomycetous fungi.
5. In Praise of Openness
NASA Astrophysics Data System (ADS)
Arunachalam, S.
2010-10-01
Open access brings greater visibility and impact to the work of scientists as is evidenced in the examples discussed in this paper. Researchers are often reluctant and afraid to deposit their works in Institutional Repositories. However, as is shown here, once they do so, they do not regret it. Open access will shortly become the norm and will be accepted by the vast majority of scientists. Seen through the lens of the philosophy of Bertrand Russell, the moral, economic and philosophical imperatives for open access are indeed strong.
6. Mitigation of wind tunnel wall interactions in subsonic cavity flows
SciTech Connect
Wagner, Justin L.; Casper, Katya Marie; Beresh, Steven J.; Henfling, John F.; Spillers, Russell Wayne; Pruett, Brian Owen Matthew
2015-03-06
In this study, the flow over an open aircraft bay is often represented in a wind tunnel with a cavity. In flight, this flow is unconfined, though in experiments, the cavity is surrounded by wind tunnel walls. If untreated, wind tunnel wall effects can lead to significant distortions of cavity acoustics in subsonic flows. To understand and mitigate these cavity–tunnel interactions, a parametric approach was taken for flow over an L/D = 7 cavity at Mach numbers 0.6–0.8. With solid tunnel walls, a dominant cavity tone was observed, likely due to an interaction with a tunnel duct mode. Furthermore, an acoustic liner opposite the cavity decreased the amplitude of the dominant mode and its harmonics, a result observed by previous researchers. Acoustic dampeners were also placed in the tunnel sidewalls, which further decreased the dominant mode amplitudes and peak amplitudes associated with nonlinear interactions between cavity modes. This then indicates that cavity resonance can be altered by tunnel sidewalls and that spanwise coupling should be addressed when conducting subsonic cavity experiments. Though mechanisms for dominant modes and nonlinear interactions likely exist in unconfined cavity flows, these effects can be amplified by the wind tunnel walls.
7. Mitigation of wind tunnel wall interactions in subsonic cavity flows
DOE PAGES
Wagner, Justin L.; Casper, Katya Marie; Beresh, Steven J.; ...
2015-03-06
In this study, the flow over an open aircraft bay is often represented in a wind tunnel with a cavity. In flight, this flow is unconfined, though in experiments, the cavity is surrounded by wind tunnel walls. If untreated, wind tunnel wall effects can lead to significant distortions of cavity acoustics in subsonic flows. To understand and mitigate these cavity–tunnel interactions, a parametric approach was taken for flow over an L/D = 7 cavity at Mach numbers 0.6–0.8. With solid tunnel walls, a dominant cavity tone was observed, likely due to an interaction with a tunnel duct mode. Furthermore, anmore » acoustic liner opposite the cavity decreased the amplitude of the dominant mode and its harmonics, a result observed by previous researchers. Acoustic dampeners were also placed in the tunnel sidewalls, which further decreased the dominant mode amplitudes and peak amplitudes associated with nonlinear interactions between cavity modes. This then indicates that cavity resonance can be altered by tunnel sidewalls and that spanwise coupling should be addressed when conducting subsonic cavity experiments. Though mechanisms for dominant modes and nonlinear interactions likely exist in unconfined cavity flows, these effects can be amplified by the wind tunnel walls.« less
8. Catalysts of plant cell wall loosening
PubMed Central
Cosgrove, Daniel J.
2016-01-01
The growing cell wall in plants has conflicting requirements to be strong enough to withstand the high tensile forces generated by cell turgor pressure while selectively yielding to those forces to induce wall stress relaxation, leading to water uptake and polymer movements underlying cell wall expansion. In this article, I review emerging concepts of plant primary cell wall structure, the nature of wall extensibility and the action of expansins, family-9 and -12 endoglucanases, family-16 xyloglucan endotransglycosylase/hydrolase (XTH), and pectin methylesterases, and offer a critical assessment of their wall-loosening activity PMID:26918182
9. Commentary: open access, open business, closed fairness!
PubMed
Moustafa, Khaled
2015-01-01
A strong trend to move from print to online publication is largely perceived in scientific and nonscientific fields. A growing number of publishers increasingly opt for online publication as an option or a compulsory alternative. From readers' perspective, this is a highly appreciated facility, but from the author's, things are different mainly because of excessive article processing charges (APC) that make the open access system sometimes as a hindrance for many authors but a lucrative enterprise for many shareholders, enticing the most traditional and conservative publishers.
10. Defining Open Education
ERIC Educational Resources Information Center
Walberg, Herbert J.; Thomas, Susan Christie
1974-01-01
Authors believed that sharper definitions of open education can keep the current movement authentic to its early consensus ideals while avoiding dogma, orthodoxy, discipleships: charisma, and latter-day carpetbagging. (Author/RK)
11. Open Rotor Spin Test
NASA Video Gallery
An open rotor, also known as a high-speed propeller, is tested in a wind tunnel. The propeller moves much more quickly than a standard propeller, and the blades of the propeller are shaped differen...
12. Open cycle thermoacoustics
SciTech Connect
Reid, Robert Stowers
2000-01-01
A new type of thermodynamic device combining a thermodynamic cycle with the externally applied steady flow of an open thermodynamic process is discussed and experimentally demonstrated. The gas flowing through this device can be heated or cooled in a series of semi-open cyclic steps. The combination of open and cyclic flows makes possible the elimination of some or all of the heat exchangers (with their associated irreversibility). Heat is directly exchanged with the process fluid as it flows through the device when operating as a refrigerator, producing a staging effect that tends to increase First Law thermodynamic efficiency. An open-flow thermoacoustic refrigerator was built to demonstrate this concept. Several approaches are presented that describe the physical characteristics of this device. Tests have been conducted on this refrigerator with good agreement with a proposed theory.
13. Vacuum interrupters and thyratrons as opening switches
SciTech Connect
Honig, E.M.
1981-01-01
The clear advantages of inductive storage for large scale energy storage applications are creating an increasing interest in the research and development of the opening switches required. Opening switches for single-shot inductive transfers have received considerable attention and are fairly well advanced. The problem addressed by this workshop of high power opening switches for high repetition rate applications is much more severe, however, and may well require a major research and development effort. Two candidates for such an opening switch, the triggered vacuum interrupter and the magnetically quenched thyratron, are discussed. By electrically retriggering the discharge in the vacuum interrupter between pulses, the dependence on mechanical motion is eliminated. This should enable repetition rate operation at 10 to 15 kHz while still maintaining the vacuum interrupter's proven interrupting performance of tens of kiloamps at tens of kilovolts. The magnetically quenched thyratron, on the other hand, uses a cross magnetic field to raise the switch impedance by decreasing the electron mobility and driving the discharge into an arc chute wall where it is quenched. Successful interruptions of 1 kA at 15 kV and 100 A at 50 kV after conduction for 10 ..mu..s have been demonstrated by previous researchers. Work at Los Alamos is directed toward understanding the basic mechanisms involved and increasing the switch ratings, particularly the conduction time.
14. PWC Opens up
ERIC Educational Resources Information Center
Weinstein, Margery
2011-01-01
Coming up with the latest and greatest learning curriculum for employees year after year can be overwhelming--especially if one works for a small or mid-size company with minimal resources. Fortunately, there is a burgeoning trend that three-time No. 1 Top 125er PwC is helping to "open" up. In creating PwC Open University, the professional…
15. Open source molecular modeling.
PubMed
Pirhadi, Somayeh; Sunseri, Jocelyn; Koes, David Ryan
2016-09-01
The success of molecular modeling and computational chemistry efforts are, by definition, dependent on quality software applications. Open source software development provides many advantages to users of modeling applications, not the least of which is that the software is free and completely extendable. In this review we categorize, enumerate, and describe available open source software packages for molecular modeling and computational chemistry. An updated online version of this catalog can be found at https://opensourcemolecularmodeling.github.io.
16. OpenTopography
NASA Astrophysics Data System (ADS)
Baru, C.; Arrowsmith, R.; Crosby, C.; Nandigam, V.; Phan, M.; Cowart, C.
2012-04-01
OpenTopography is a cyberinfrastructure-based facility for online access to high-resolution topography and tools. The project is an outcome of the Geosciences Network (GEON) project, which was a research project funded several years ago in the US to investigate the use of cyberinfrastructure to support research and education in the geosciences. OpenTopography provides online access to large LiDAR point cloud datasets along with services for processing these data. Users are able to generate custom DEMs by invoking DEM services provided by OpenTopography with custom parameter values. Users can track the progress of their jobs, and a private myOpenTopo area retains job information and job outputs. Data available at OpenTopography are provided by a variety of data acquisition groups under joint agreements and memoranda of understanding (MoU). These include national facilities such as the National Center for Airborne Lidar Mapping, as well as local, state, and federal agencies. OpenTopography is also being designed as a hub for high-resolution topography resources. Datasets and services available at other locations can also be registered here, providing a "one-stop shop" for such information. We will describe the OpenTopography system architecture and its current set of features, including the service-oriented architecture, a job-tracking database, and social networking features. We will also describe several design and development activities underway to archive and publish datasets using digital object identifiers (DOIs); create a more flexible and scalable high-performance environment for processing of large datasets; extend support for satellite-based and terrestrial lidar as well as synthetic aperture radar (SAR) data; and create a "pluggable" infrastructure for third-party services. OpenTopography has successfully created a facility for sharing lidar data. In the next phase, we are developing a facility that will also enable equally easy and successful sharing of
17. The Open AUC Project.
PubMed
Cölfen, Helmut; Laue, Thomas M; Wohlleben, Wendel; Schilling, Kristian; Karabudak, Engin; Langhorst, Bradley W; Brookes, Emre; Dubbs, Bruce; Zollars, Dan; Rocco, Mattia; Demeler, Borries
2010-02-01
Progress in analytical ultracentrifugation (AUC) has been hindered by obstructions to hardware innovation and by software incompatibility. In this paper, we announce and outline the Open AUC Project. The goals of the Open AUC Project are to stimulate AUC innovation by improving instrumentation, detectors, acquisition and analysis software, and collaborative tools. These improvements are needed for the next generation of AUC-based research. The Open AUC Project combines on-going work from several different groups. A new base instrument is described, one that is designed from the ground up to be an analytical ultracentrifuge. This machine offers an open architecture, hardware standards, and application programming interfaces for detector developers. All software will use the GNU Public License to assure that intellectual property is available in open source format. The Open AUC strategy facilitates collaborations, encourages sharing, and eliminates the chronic impediments that have plagued AUC innovation for the last 20 years. This ultracentrifuge will be equipped with multiple and interchangeable optical tracks so that state-of-the-art electronics and improved detectors will be available for a variety of optical systems. The instrument will be complemented by a new rotor, enhanced data acquisition and analysis software, as well as collaboration software. Described here are the instrument, the modular software components, and a standardized database that will encourage and ease integration of data analysis and interpretation software.
18. Open field lines instabilities
SciTech Connect
Pozzoli, R. |
1995-09-01
The results of some recent theoretical papers dealing with flute-like instabilities in the scrape-off layer of a tokamak with limiter configuration, where the magnetic field intersects conducting walls, are briefly recalled. Attention is then paid to the instability driven by the electron temperature gradient across the field in conjunction with the formation of the Debye sheath at the boundary, and to the effects due to the inclination of the end walls with respect to the magnetic field. When a divertor configuration is considered, important modifications are found owing to the strong deformations of the flux tubes passing near the {ital x}-point, which contrast the onset of flute-like perturbations, and to the stochasticity of field lines that can be excited by magnetic field perturbations. {copyright} {ital 1995 American Institute of Physics.}
19. Single-walled carbon nanotubes as near-infrared optical biosensors for life sciences and biomedicine.
PubMed
Jain, Astha; Homayoun, Aida; Bannister, Christopher W; Yum, Kyungsuk
2015-03-01
Single-walled carbon nanotubes that emit photostable near-infrared fluorescence have emerged as near-infrared optical biosensors for life sciences and biomedicine. Since the discovery of their near-infrared fluorescence, researchers have engineered single-walled carbon nanotubes to function as an optical biosensor that selectively modulates its fluorescence upon binding of target molecules. Here we review the recent advances in the single-walled carbon nanotube-based optical sensing technology for life sciences and biomedicine. We discuss the structure and optical properties of single-walled carbon nanotubes, the mechanisms for molecular recognition and signal transduction in single-walled carbon nanotube complexes, and the recent development of various single-walled carbon nanotube-based optical biosensors. We also discuss the opportunities and challenges to translate this emerging technology into biomedical research and clinical use, including the biological safety of single-walled carbon nanotubes. The advances in single-walled carbon nanotube-based near-infrared optical sensing technology open up a new avenue for in vitro and in vivo biosensing with high sensitivity and high spatial resolution, beneficial for many areas of life sciences and biomedicine.
20. Comparison of conventional and adaptive wall wind tunnel results with regard to Reynolds number effects
NASA Technical Reports Server (NTRS)
Stanewsky, E.; Freimuth, P.
1989-01-01
A comparison of results from conventional and adaptive wall wind tunnels with regard to Reynolds number effects was carried out. The special objective of this comparison was to confirm or reject earlier conclusions, soley based on conventional wind tunnel results, concerning the influence of viscous effects on the characteristics of partially open wind tunnel walls, hence wall interference. The following postulations could be confirmed: (1) certain classes of supercritical airfoils exhibit a non-linear increase in lift which is, at least in part, related to viscous-inviscid interactions on the airfoil. This non-linear lift characteristic can erroneously be suppressed by sidewall interference effects in addition to being affected by changes in Reynolds number. Adaptive walls seem to relieve the influence of sidewall interference; (2) the degree of (horizontal) wall interference effects can be significantly affected by changes in Reynolds number, thus appearing as true Reynolds number effects; (3) perforated wall characteristics seem much more susceptible to viscous changes than the characteristics of slotted walls; here, blockage interference may be most severely influenced by viscous changes; and (4) real Reynolds number effects are present on the CAST 10-2/DOA 2 airfoil; they were shown to be appreciable also by the adaptive wall wind tunnel tests.
1. RESISTIVE WALL STABILIZATION OF HIGH BETA PLASMAS IN DIII-D
SciTech Connect
STRAIT,EJ; BIALEK,J; BOGATU,N; CHANCE,M; CHU,MS; EDGELL,D; GAROFALO,AM; JACKSON,GL; JENSEN,TH; JOHNSON,LC; KIM,JS; LAHAYE,RJ; NAVRATIL,G; OKABAYASHI,M; REIMERDES,H; SCOVILLE,JT; TURNBULL,AD; WALKER,ML
2002-09-01
OAK A271 RESISTIVE WALL STABILIZATION OF HIGH BETA PLASMAS IN DIII-D. Recent DIII-D experiments show that ideal kink modes can be stabilized at high beta by a resistive wall, with sufficient plasma rotation. However, the resonant response by a marginally stable resistive wall mode to static magnetic field asymmetries can lead to strong damping of the rotation. Careful reduction of such asymmetries has allowed plasmas with beta well above the ideal MHD no-wall limit, and approaching the ideal-wall limit, to be sustained for durations exceeding one second. Feedback control can improve plasma stability by direct stabilization of the resistive wall mode or by reducing magnetic field asymmetry. Assisted by plasma rotation, direct feedback control of resistive wall modes with growth rates more than 5 times faster than the characteristic wall time has been observed. These results open a new regime of tokamak operation above the free-boundary stability limit, accessible by a combination of plasma rotation and feedback control.
2. Active and passive kink mode studies in a tokamak with a movable ferromagnetic wall
SciTech Connect
Levesque, J. P.; Hughes, P. E.; Bialek, J.; Byrne, P. J.; Mauel, M. E.; Navratil, G. A.; Peng, Q.; Rhodes, D. J.; Stoafer, C. C.
2015-05-15
High-resolution active and passive kink mode studies are conducted in a tokamak with an adjustable ferromagnetic wall near the plasma surface. Ferritic tiles made from 5.6 mm thick Hiperco{sup ®} 50 alloy have been mounted on the plasma-facing side of half of the in-vessel movable wall segments in the High Beta Tokamak-Extended Pulse device [D. A. Maurer et al., Plasma Phys. Controlled Fusion 53, 074016 (2011)] in order to explore ferritic resistive wall mode stability. Low-activation ferritic steels are a candidate for structural components of a fusion reactor, and these experiments examine MHD stability of plasmas with nearby ferromagnetic material. Plasma-wall separation for alternating ferritic and non-ferritic wall segments is adjusted between discharges without opening the vacuum vessel. Amplification of applied resonant magnetic perturbations and plasma disruptivity are observed to increase when the ferromagnetic wall is close to plasma surface instead of the standard stainless steel wall. Rapidly rotating m/n=3/1 external kink modes have higher growth rates with the nearby ferritic wall. Feedback suppression of kinks is still as effective as before the installation of ferritic material in vessel, in spite of increased mode growth rates.
3. Flame front propagation in a channel with porous walls
NASA Astrophysics Data System (ADS)
Golovastov, S. V.; Bivol, G. Yu
2016-11-01
Propagation of the detonation front in hydrogen-air mixture was investigated in rectangular cross-section channels with sound-absorbing boundaries. The front of luminescence was detected in a channel with acoustically absorbing walls as opposed to a channel with solid walls. Flame dynamics was recorded using a high-speed camera. The flame was observed to have a V-shaped profile in the acoustically absorbing section. The possible reason for the formation of the V-shaped flame front is friction under the surface due to open pores. In these shear flows, the kinetic energy of the flow on the surface can be easily converted into heat. A relatively small disturbance may eventually lead to significant local stretching of the flame front surface. Trajectories of the flame front along the axis and the boundary are presented for solid and porous surfaces.
4. Dynamic behavior of braced thin-walled beams
NASA Astrophysics Data System (ADS)
Prokić, A.; Lukić, D.
2007-11-01
The present paper considers the dynamic behavior of beams with open thin-walled cross-sections along their length with bracings (connecting beams and truss). The effect of the constrained torsion warping, rotary inertia, and flexural-torsion coupling due to nonsymmetric cross-sections is included. In the case of simply supported beams, closed-form solutions for determining coupled natural frequencies and corresponding mode shapes are newly derived. The frequency equation, given in a determinantal form, is expanded in an explicit analytical form and then solved using the Mathcad 2001 Professional symbolic computing package. Some illustrative examples on the application of the present theory are given for coupled bending-torsion vibrations of braced thin-walled beams. As compared with FEM, numerical results demonstrate the accuracy and effectiveness of the proposed method
5. Posterior left atrial wall hematoma mimicking cystic intracavitary atrial mass.
PubMed
Bahnacy, Yasser; Suresh, Cheriyil; Dawoud, Hamed; Zubaid, Mohammad
2010-10-01
Atrial myxoma is the most common benign primary tumor of the heart most commonly in the left atrium (LA). Cystic or cavitated intracardiac masses are rare. We report the case of a 43-year-old male patient admitted with chest infection, hemoptysis, and severe respiratory distress, who had to be ventilated. Chest computed tomography showed bilateral lung consolidation with large mass occupying the region of the LA. Transthoracic echocardiography and transesophageal echocardiography showed a large intracavitary left atrial cystic mobile mass. Open-heart surgical exploration did not show any mass inside the LA. A posterior left atrial wall hematoma was found and evacuated. Biopsies confirmed the presence of blood clots. Posterior left atrial wall hematoma may appear as left atrial intracavitary cystic mass and should be included in the differential diagnosis of cystic left atrial mass.
6. rOpenSci - open tools for open science
NASA Astrophysics Data System (ADS)
Ram, K.
2013-12-01
Solving many of the basic and applied challenges in ecology and evolution requires access to large amounts of data, often spanning long spatial and temporal scales. The long-established model where researchers collect and analyze their own data will soon be replaced by one where disparate datasets are brought to bear on both basic and applied problems. As science becomes more data-driven, it faces a whole new set of challenges. Researchers will not only have to maintain expertise in their domains but also learn new skills to curate, retrieve, and analyze these newly available data. In order to fully realize the potential of data-driven science and allow researchers to draw insights from these vast data stores, we need to address challenges associated with all aspects of the research life cycle. To foster and support a new generation of data-driven science, my colleagues and I founded a project called rOpenSci (http://ropensci.org). The project is an integrated effort to build tools and training using Ecology and Evolution as a model community. In this talk I will outline several of the barriers that need to be overcome including better incentive mechanisms for data, training gaps, and lowering technical barriers.
7. Direct calculation of wall interferences and wall adaptation for two-dimensional flow in wind tunnels with closed walls
NASA Technical Reports Server (NTRS)
Amecke, Juergen
1986-01-01
A method for the direct calculation of the wall induced interference velocity in two dimensional flow based on Cauchy's integral formula was derived. This one-step method allows the calculation of the residual corrections and the required wall adaptation for interference-free flow starting from the wall pressure distribution without any model representation. Demonstrated applications are given.
8. A Near-Wall Reynolds-Stress Closure Without Wall Normals
NASA Technical Reports Server (NTRS)
Yuan, S. P.; So, R. M. C.
1997-01-01
Turbulent wall-bounded complex flows are commonly encountered in engineering practice and are of considerable interest in a variety of industrial applications. The presence of a wall significantly affects turbulence characteristics. In addition to the wall effects, turbulent wall-bounded flows become more complicated by the presence of additional body forces (e.g. centrifugal force and Coriolis force) and complex geometry. Most near-wall Reynolds stress models are developed from a high-Reynolds-number model which assumes turbulence is homogenous (or quasi-homogenous). Near-wall modifications are proposed to include wall effects in near-wall regions. In this process, wall normals are introduced. Good predictions could be obtained by Reynolds stress models with wall normals. However, ambiguity arises when the models are applied in flows with multiple walls. Many models have been proposed to model turbulent flows. Among them, Reynolds stress models, in which turbulent stresses are obtained by solving the Reynolds stress transport equations, have been proved to be the most successful ones. To apply the Reynolds stress models to wall-bounded flows, near-wall corrections accounting for the wall effects are needed, and the resulting models are called near-wall Reynolds stress models. In most of the existing near-wall models, the near-wall corrections invoke wall normals. These wall-dependent near-wall models are difficult to implement for turbulent flows with complex geometry and may give inaccurate predictions due to the ambiguity of wall normals at corners connecting multiple walls. The objective of this study is to develop a more general and flexible near-wall Reynolds stress model without using any wall-dependent variable for wall-bounded turbulent flows. With the aid of near-wall asymptotic analysis and results of direct numerical simulation, a new near-wall Reynolds stress model (NNWRS) is formulated based on Speziale et al.'s high-Reynolds-stress model with wall
9. Determination of velum opening for French nasal vowels by magnetic resonance imaging.
PubMed
Demolin, Didier; Delvaux, Véronique; Metens, Thierry; Soquet, Alain
2003-12-01
MRI techniques have been used to describe velum opening of French vowels. Data based on 18 joined axial slices of 4 mm thickness were recorded with four subjects. Differences in velum opening are calculated from areas measured in the tract between the lowered velum and the back pharynx wall. Results show that for all subjects, the back vowel [symbol: see text] has the smallest opening, while some variations are observed for the other vowels.
10. Microwave background distortions from domain walls
NASA Technical Reports Server (NTRS)
Goetz, Guenter; Noetzold, Dirk
1990-01-01
Domain walls arising in a cosmic phase transition after decoupling were recently proposed as seeds for the formation of large scale structure. The distortion induced in the microwave background radiation is calculated in dependence of the wall thickness, surface density, scalar field potential, cosmic redshift and the velocity of the wall. It was found that the maximal redshift distortion for both spherical and planar walls is of the order pi G sigma H(sup -1)(sub 0), where sigma is the surface energy density and H(sup -1)(sub 0) the Hubble parameter. It was also found that, for a wall thickness smaller than the horizon, walls can be treated as infinitely thin, i.e., the redshift distortion is independent of the wall thickness and the specific form of the scalar potential. For planar walls moving with a Lorentz-factor gamma the redshift distortion is enhanced by gamma cubed.
11. Microwave background distortions from domain walls
NASA Astrophysics Data System (ADS)
Goetz, Guenter; Noetzold, Dirk
1990-08-01
Domain walls arising in a cosmic phase transition after decoupling were recently proposed as seeds for the formation of large scale structure. The distortion induced in the microwave background radiation is calculated in dependence of the wall thickness, surface density, scalar field potential, cosmic redshift and the velocity of the wall. It was found that the maximal redshift distortion for both spherical and planar walls is of the order pi G sigma H(sup -1)(sub 0), where sigma is the surface energy density and H(sup -1)(sub 0) the Hubble parameter. It was also found that, for a wall thickness smaller than the horizon, walls can be treated as infinitely thin, i.e., the redshift distortion is independent of the wall thickness and the specific form of the scalar potential. For planar walls moving with a Lorentz-factor gamma the redshift distortion is enhanced by gamma cubed.
12. Microwave background distortions from domain walls.
NASA Astrophysics Data System (ADS)
Goetz, G.; Nötzold, D.
1991-03-01
Domain walls arising in a cosmic phase transition after decoupling were recently proposed as seeds for the formation of large-scale structure. The distortion induced in the microwave background radiation is calculated in dependence of the wall thickness, surface density, scalar field potential, cosmic redshift and the velocity of the wall. The authors find that the maximal redshift distortion for both spherical and planar walls is of the order πGσH0-1, where σ is the surface energy density and H0 the Hubble parameter. They also find that, for a wall thickness smaller than the horizon, walls can be treated as infinitely thin, i.e. the redshift distortion is independent of the wall thickness and the specific form of the scalar potential. For planar walls moving with a Lorentz-factor γ the redshift distortion is enhanced by γ3.
13. openPMD-viewer
SciTech Connect
Lehe, Remi
2015-10-01
Many simulation software produce data in the form of a set of field values or of a set of particle positions. (one such example is that of particle-in-cell codes, which produce data on the electromagnetic fields that they simulate.) However, each particular software uses its own particular format and layout, for the output data. This makes it difficult to compare the results of different simulation software, or to have a common visualization tool for these results. However, a standardized layout for fields and particles has recently been developed: the openPMD format ( HYPERLINK "http://www.openpmd.org/"www.openpmd.org) This format is open- source, and specifies a standard way in which field data and particle data should be written. The openPMD format is already implemented in the particle-in-cell code Warp (developed at LBL) and in PIConGPU (developed at HZDR, Germany). In this context, the proposed software (openPMD-viewer) is a Python package, which allows to access and visualize any data which has been formatted according to the openPMD standard. This package contains two main components: - a Python API, which allows to read and extract the data from a openPMD file, so as to be able to work with it within the Python environment. (e.g. plot the data and reprocess it with particular Python functions) - a graphical interface, which works with the ipython notebook, and allows to quickly visualize the data and browse through a set of openPMD files. The proposed software will be typically used when analyzing the results of numerical simulations. It will be useful to quickly extract scientific meaning from a set of numerical data.
14. Simulation of turbulent wall pressure
NASA Technical Reports Server (NTRS)
Ash, R. L.
1978-01-01
A Monte Carlo procedure was developed to simulate turbulent boundary layer wall pressure fluctuations. The approach utilizes much of the newly available conditional sampling information to construct the required distribution functions. Various disturbance wave forms were examined, as well as the effect of frequency-dependent decay. Good agreement between the simulation and experimental data was achieved for root mean square pressure level, power spectrum, and space time correlation.
15. Effects of honeycomb shaped walls on the flow regime between a rotating disk and a stationary wall
NASA Astrophysics Data System (ADS)
Uzkan, T.; Lipstein, N. J.
1986-06-01
In order to cool a gas turbine disk with a limited supply of coolant air, the radial inflow of hot gases between rotor disk and housing must be reduced. Attention is presently given to the use of different surface shapes on the stationary housing to inhibit disk pumping capacity and hence to reduce the radial influx of hot gases into the clearance. The basic geometry that was experimentally investigated was the flow field between a smooth cylindrical rotating disk parallel to a plain circular coaxial wall open to the free space at the disk periphery. The results obtained are presented in terms of the tangential and radial velocity profiles in the gap, the static pressure measurements, and the disk torque coefficients. A honeycombed stationary wall surface had a profound effect on the ingestion of external flow into the gap from the disk periphery.
16. How do plant cell walls extend?
NASA Technical Reports Server (NTRS)
Cosgrove, D. J.
1993-01-01
This article briefly summarizes recent work that identifies the biophysical and biochemical processes that give rise to the extension of plant cell walls. I begin with the biophysical notion of stress relaxation of the wall and follow with recent studies of wall enzymes thought to catalyze wall extension and relaxation. Readers should refer to detailed reviews for more comprehensive discussion of earlier literature (Taiz, 1984; Carpita and Gibeaut, 1993; Cosgrove, 1993).
17. Tube wall thickness measurement apparatus
DOEpatents
Lagasse, P.R.
1985-06-21
An apparatus for measuring the thickness of a tube's wall for the tube's entire length and radius by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.
18. Tube wall thickness measurement apparatus
DOEpatents
Lagasse, Paul R.
1987-01-01
An apparatus for measuring the thickness of a tube's wall for the tube's entire length and circumference by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.
19. Making Your Music Word Wall Work
ERIC Educational Resources Information Center
Leonhardt, Angela
2011-01-01
This article looks at what a word wall is and its use in the music classroom. The author outlines steps for creation of a word wall within the music classroom as well as the importance of such a resource. The author encourages the creation and consistent use of the word wall as leading to the development of stronger musicians and also independent,…
20. Methods & Strategies: Put Your Walls to Work
ERIC Educational Resources Information Center
Jackson, Julie; Durham, Annie
2016-01-01
This column provides ideas and techniques to enhance your science teaching. This month's issue discusses planning and using interactive word walls to support science and reading instruction. Many classrooms have word walls displaying vocabulary that students have learned in class. Word walls serve as visual scaffolds to support instruction. To…
1. Global OpenSearch
NASA Astrophysics Data System (ADS)
Newman, D. J.; Mitchell, A. E.
2015-12-01
At AGU 2014, NASA EOSDIS demonstrated a case-study of an OpenSearch framework for Earth science data discovery. That framework leverages the IDN and CWIC OpenSearch API implementations to provide seamless discovery of data through the 'two-step' discovery process as outlined by the Federation for Earth Sciences (ESIP) OpenSearch Best Practices. But how would an Earth Scientist leverage this framework and what are the benefits? Using a client that understands the OpenSearch specification and, for further clarity, the various best practices and extensions, a scientist can discovery a plethora of data not normally accessible either by traditional methods (NASA Earth Data Search, Reverb, etc) or direct methods (going to the source of the data) We will demonstrate, via the CWICSmart web client, how an earth scientist can access regional data on a regional phenomena in a uniform and aggregated manner. We will demonstrate how an earth scientist can 'globalize' their discovery. You want to find local data on 'sea surface temperature of the Indian Ocean'? We can help you with that. 'European meteorological data'? Yes. 'Brazilian rainforest satellite imagery'? That too. CWIC allows you to get earth science data in a uniform fashion from a large number of disparate, world-wide agencies. This is what we mean by Global OpenSearch.
2. Using two soft computing methods to predict wall and bed shear stress in smooth rectangular channels
NASA Astrophysics Data System (ADS)
Khozani, Zohreh Sheikh; Bonakdari, Hossein; Zaji, Amir Hossein
2017-03-01
Two soft computing methods were extended in order to predict the mean wall and bed shear stress in open channels. The genetic programming (GP) and Genetic Algorithm Artificial Neural Network (GAA) were investigated to determine the accuracy of these models in estimating wall and bed shear stress. The GP and GAA model results were compared in terms of testing dataset in order to find the best model. In modeling both bed and wall shear stress, the GP model performed better with RMSE of 0.0264 and 0.0185, respectively. Then both proposed models were compared with equations for rectangular open channels, trapezoidal channels and ducts. According to the results, the proposed models performed the best in predicting wall and bed shear stress in smooth rectangular channels. The obtained equation for rectangular channels could estimate values closer to experimental data, but the equations for ducts had poor, inaccurate results in predicting wall and bed shear stress. The equation presented for trapezoidal channels did not have acceptable accuracy in predicting wall and bed shear stress either.
3. 19. INTERIOR OF UTILITY ROOM SHOWING STUCCO WALL/DRYWALL WALL TRANSITION, ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
19. INTERIOR OF UTILITY ROOM SHOWING STUCCO WALL/DRYWALL WALL TRANSITION, ELECTRICAL JUNCTION BOXES, BUILT-IN WALL CABINETRY, AND ELECTRICAL WALL HEATER. VIEW TO NORTHEAST. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA
4. The Writing on the Wall: Attending to Self-Motivated Student Literacies.
ERIC Educational Resources Information Center
Weinstein, Susan
2002-01-01
Explores the role that tagging (a simple form of graffiti) plays around the school and community. Argues that even the writing of a name on a wall opens out into a rich discourse community, in which taggers carry on complex conversations, negotiate and challenge shared discursive norms, and develop identities that are intimately connected to a…
5. Greenery vs. Concrete and Walls and Doors: Images and Metaphors Affecting an Urban Mission.
ERIC Educational Resources Information Center
Severino, Carl
1995-01-01
The traditional pastoralism of American higher education has interfered with efforts to develop an urban mission for the university. In addition, current open-door metaphors of access, political trends, and media coverage are promulgating closed-door, wall-building rhetoric and policies. Now is the time to counter antiurban attitudes by reviving…
6. Open system environment procurement
NASA Technical Reports Server (NTRS)
Fisher, Gary
1994-01-01
Relationships between the request for procurement (RFP) process and open system environment (OSE) standards are described. A guide was prepared to help Federal agency personnel overcome problems in writing an adequate statement of work and developing realistic evaluation criteria when transitioning to an OSE. The guide contains appropriate decision points and transition strategies for developing applications that are affordable, scalable and interoperable across a broad range of computing environments. While useful, the guide does not eliminate the requirement that agencies posses in-depth expertise in software development, communications, and database technology in order to evaluate open systems.
7. Bargaining for Open Skies
NASA Technical Reports Server (NTRS)
Wojahn, Oliver W.
2001-01-01
In this paper we analyze the bargaining problem between countries when negotiating bilateral air service agreements. To do so, we use the methods of bargaining and game theory. We give special attention to the case where a liberal minded country is trying to convince a less liberal country to agree to bilateral open skies, and the liberal country might also unilaterally open up its market. The following analysis is positive in the sense that the results help explain and predict the outcome of negotiations under different payoffs and structures of the bargaining process. They are normative in the sense that adequate manipulation of the bargaining conditions can ensure a desired outcome.
8. Asymmetric counter propagation of domain walls
NASA Astrophysics Data System (ADS)
Andrade-Silva, I.; Clerc, M. G.; Odent, V.
2016-07-01
Far from equilibrium systems show different states and domain walls between them. These walls, depending on the type of connected equilibria, exhibit a rich spatiotemporal dynamics. Here, we investigate the asymmetrical counter propagation of domain walls in an in-plane-switching cell filled with a nematic liquid crystal. Experimentally, we characterize the shape and speed of the domain walls. Based on the molecular orientation, we infer that the counter propagative walls have different elastic deformations. These deformations are responsible of the asymmetric counter propagating fronts. Theoretically, based on symmetry arguments, we propose a simple bistable model under the influence of a nonlinear gradient, which qualitatively describes the observed dynamics.
9. Experimental investigation of wall shock cancellation and reduction of wall interference in transonic testing
NASA Technical Reports Server (NTRS)
Ferri, A.; Roffe, G.
1975-01-01
A series of experiments were performed to evaluate the effectiveness of a three-dimensional land and groove wall geometry and a variable permeability distribution to reduce the interference produced by the porous walls of a supercritical transonic test section. The three-dimensional wall geometry was found to diffuse the pressure perturbations caused by small local mismatches in wall porosity permitting the use of a relatively coarse wall porosity control to reduce or eliminate wall interference effects. The wall porosity distribution required was found to be a sensitive function of Mach number requiring that the Mach number repeatability characteristics of the test apparatus be quite good. The effectiveness of a variable porosity wall is greatest in the upstream region of the test section where the pressure differences across the wall are largest. An effective variable porosity wall in the down stream region of the test section requires the use of a slightly convergent test section geometry.
10. A swirl generator case study for OpenFOAM
NASA Astrophysics Data System (ADS)
Petit, O.; Bosioc, A. I.; Nilsson, H.; Muntean, S.; Susan-Resiga, R. F.
2010-08-01
This work presents numerical results, using OpenFOAM, of the flow in the swirl flow generator test rig developed at Politehnica University of Timisoara, Romania. The work shows results computed by solving the unsteady Reynolds Averaged Navier Stokes equations. The unsteady method couples the rotating and stationary parts using a sliding grid interface based on a GGI formulation. Turbulence is modeled using the standard k-epsilon model, and block structured wall function ICEM-Hexa meshes are used. The numerical results are validated against experimental LDV results, and against designed velocity profiles. The investigation shows that OpenFOAM gives results that are comparable to the experimental and designed profiles. This case study was presented at the 5th OpenFOAM Workshop, held in Gothenburg, Sweden, as a tutorial on how to treat turbomachinery applications in OpenFOAM.
11. How Vein Sealing Boosts Fracture Opening
NASA Astrophysics Data System (ADS)
Nüchter, Jens-Alexander
2015-04-01
Veins from from cracks. As such, a stage of brittle failure and fracturing is to be set apart from a stage of opening and sealing. The process of fracture opening requires distortion of the host rocks to create space for the evolving vein. To keep a crack arrested and, at the same time, to widen or stabilize the cavity, the stress intensity factor K_I=(P-S3)(πa) must remain below the fracture toughness K_IC of the host rock, and P-S3 >0 (P and S3 denote pore fluid pressure and absolute minimum principal stress, respectively and 'a' refers to the half-length of the fracture). For purely elastic distortion of the host rocks, maximum aperture W0=K_IC (1-ν^2)/(E(π/8)^1/2))(2a)^1/2 depends on on K_IC, Poisson's ratio ν, and Young's modulus E of the host rocks. Owing to the low values for rock K_IC typically ranging between 0.1 and 1 MPa m^1/2, veins formed by purely elastic distortion of the host rocks are restricted to high aspect ratios 2a/W. In metamorphic rocks, veins with low aspect ratios are common; inelastic deformation and viscous creep in the host rocks must have contributed to final vein shapes. In the present study, I use finite element models to simulate fracture opening and cavity formation supported by viscous creep distributed in the host rock. Simulations are carried out on 2D plate models containing elliptical fractures. The walls of the fractures are coated by thin layers simulating incipient sealing; a residual cavity prevails in the centre of the model veins. Constant displacement is applied to the plate boundaries oriented normal to the cracks. I run a series of models with various viscosity contrasts between the rocks and the sealing. The results of these models indicate the following. (1) Fracture opening is most effective when the viscosity of the sealing ηs exceeds the viscosity of the host rocks ηr (2) The rate of fracture opening increases with increasing values for ηs/ηr . (3) An increase in the thickness of the sealing layer causes
12. Chest wall reconstruction after extended resection
PubMed Central
Seder, Christopher W.
2016-01-01
Extensive chest wall resection and reconstruction is a challenging procedure that requires a multidisciplinary approach, including input from thoracic surgeons, plastic surgeons, neurosurgeons, and radiation oncologists. The primary goals of any chest wall reconstruction is to obliterate dead space, restore chest wall rigidity, preserve pulmonary mechanics, protect intrathoracic organs, provide soft tissue coverage, minimize deformity, and allow patients to receive adjuvant radiotherapy. Successful chest wall reconstruction requires the re-establishment of skeletal stability to prevent chest wall hernias, avoids thoracoplasty-like contraction of the operated side, protects underlying viscera, and maintain a cosmetically-acceptable appearance. After skeletal stability is established, full tissue coverage can be achieved using direct closure, skin grafts, local advancement flaps, pedicled myocutaneous flaps, or free flaps. This review examines the indications for chest wall reconstruction and describes techniques for establishment of chest wall rigidity and soft tissue coverage. PMID:27942408
13. Generalized Wall Function for Complex Turbulent Flows
NASA Technical Reports Server (NTRS)
Shih, Tsan-Hsing; Povinelli, Louis A.; Liu, Nan-Suey; Chen, Kuo-Huey
2000-01-01
A generalized wall function was proposed by Shih et al., (1999). It accounts the effect of pressure gradients on the flow near the wall. Theory shows that the effect of pressure gradients on the flow in the inertial sublayer is very significant and the standard wall function should be replaced by a generalized wall function. Since the theory is also valid for boundary layer flows toward separation, the generalized wall function may be applied to complex turbulent flows with acceleration, deceleration, separation and recirculation. This paper is to verify the generalized wall function with numerical simulations for boundary layer flows with various adverse and favorable pressure gradients, including flows about to separate. Furthermore, a general procedure of implementation of the generalized wall function for National Combustion Code (NCC) is described, it can be applied to both structured and unstructured CFD codes.
14. Pulmonary complications of abdominal wall defects.
PubMed
Panitch, Howard B
2015-01-01
The abdominal wall is an integral component of the chest wall. Defects in the ventral abdominal wall alter respiratory mechanics and can impair diaphragm function. Congenital abdominal wall defects also are associated with abnormalities in lung growth and development that lead to pulmonary hypoplasia, pulmonary hypertension, and alterations in thoracic cage formation. Although infants with ventral abdominal wall defects can experience life-threatening pulmonary complications, older children typically experience a more benign respiratory course. Studies of lung and chest wall function in older children and adolescents with congenital abdominal wall defects are few; such investigations could provide strategies for improved respiratory performance, avoidance of respiratory morbidity, and enhanced exercise ability for these children.
15. Near-wall serpentine cooled turbine airfoil
SciTech Connect
Lee, Ching-Pang
2013-09-17
A serpentine coolant flow path (54A-54G) formed by inner walls (50, 52) in a cavity (49) between pressure and suction side walls (22, 24) of a turbine airfoil (20A). A coolant flow (58) enters (56) an end of the airfoil, flows into a span-wise channel (54A), then flows forward (54B) over the inner surface of the pressure side wall, then turns behind the leading edge (26), and flows back along a forward part of the suction side wall, then follows a loop (54E) forward and back around an inner wall (52), then flows along an intermediate part of the suction side wall, then flows into an aft channel (54G) between the pressure and suction side walls, then exits the trailing edge (28). This provides cooling matched to the heating topography of the airfoil, minimizes differential thermal expansion, revives the coolant, and minimizes the flow volume needed.
16. [A case of huge abscess extended from anterior neck to left lung and lateral chest wall].
PubMed
Ikeya, T; Tsuda, M; Hara, H; Koyama, S; Sugiyama, S; Misaki, T
1997-11-01
62-year-old woman admitted our hospital with pain of left upper extremity from the left chest and dysphasia. Chest X-ray showed the huge mass shadow in the left lung field. Diabetes mellitus and inflammatory reaction such as high fervor, leukocytosis, CRP and ESR accentuation were recognized. Conservative therapy was done at first, but mass shadow on X-ray increased, and swelling appeared from the neck to the left lateral chest wall. And the same site appeared like subcutaneous emphysema. Computed Tomography showed mass shadow which was enlarged and spread in lung parenchyma and left chest wall with bubble image. Incision and open drainage was performed for the left chest wall but origin bacteria was detected in neither anaerobic nor aerobic culture of pus. Inflammation and mass shadow of left upper lung field have decreased gradually. The patient discharged without bronchoalveolar fistula. Abscess extending from the neck or chest wall with diabetes mellitus is very rare.
17. Open Entry/Open Exit Study. Final Report.
ERIC Educational Resources Information Center
Berg, Marvin
Open entry/open exit refers to formats and procedures which allow learners to enter a program whenever they are ready and available, and allows them to leave or complete programs when competencies for job entry are attained. This study sought to provide base data on the concept of open entry/open exit by surveying involved individuals and to…
18. POROUS WALL, HOLLOW GLASS MICROSPHERES
SciTech Connect
Sexton, W.
2012-06-30
Hollow Glass Microspheres (HGM) is not a new technology. All one has to do is go to the internet and Google{trademark} HGM. Anyone can buy HGM and they have a wide variety of uses. HGM are usually between 1 to 100 microns in diameter, although their size can range from 100 nanometers to 5 millimeters in diameter. HGM are used as lightweight filler in composite materials such as syntactic foam and lightweight concrete. In 1968 a patent was issued to W. Beck of the 3M{trademark} Company for 'Glass Bubbles Prepared by Reheating Solid Glass Particles'. In 1983 P. Howell was issued a patent for 'Glass Bubbles of Increased Collapse Strength' and in 1988 H. Marshall was issued a patent for 'Glass Microbubbles'. Now Google{trademark}, Porous Wall, Hollow Glass Microspheres (PW-HGMs), the key words here are Porous Wall. Almost every article has its beginning with the research done at the Savannah River National Laboratory (SRNL). The Savannah River Site (SRS) where SRNL is located has a long and successful history of working with hydrogen and its isotopes for national security, energy, waste management and environmental remediation applications. This includes more than 30 years of experience developing, processing, and implementing special ceramics, including glasses for a variety of Department of Energy (DOE) missions. In the case of glasses, SRS and SRNL have been involved in both the science and engineering of vitreous or glass based systems. As a part of this glass experience and expertise, SRNL has developed a number of niches in the glass arena, one of which is the development of porous glass systems for a variety of applications. These porous glass systems include sol gel glasses, which include both xerogels and aerogels, as well as phase separated glass compositions, that can be subsequently treated to produce another unique type of porosity within the glass forms. The porous glasses can increase the surface area compared to 'normal glasses of a 1 to 2 order of
19. Open-Source Colorimeter
PubMed Central
Anzalone, Gerald C.; Glover, Alexandra G.; Pearce, Joshua M.
2013-01-01
The high cost of what have historically been sophisticated research-related sensors and tools has limited their adoption to a relatively small group of well-funded researchers. This paper provides a methodology for applying an open-source approach to design and development of a colorimeter. A 3-D printable, open-source colorimeter utilizing only open-source hardware and software solutions and readily available discrete components is discussed and its performance compared to a commercial portable colorimeter. Performance is evaluated with commercial vials prepared for the closed reflux chemical oxygen demand (COD) method. This approach reduced the cost of reliable closed reflux COD by two orders of magnitude making it an economic alternative for the vast majority of potential users. The open-source colorimeter demonstrated good reproducibility and serves as a platform for further development and derivation of the design for other, similar purposes such as nephelometry. This approach promises unprecedented access to sophisticated instrumentation based on low-cost sensors by those most in need of it, under-developed and developing world laboratories. PMID:23604032
20. Information of Open Systems
NASA Astrophysics Data System (ADS)
Klimontovich, Yuri L.
In the theory of communication two definitions of the concept "information" are known. One of them coincides according to its form with the Boltzmann entropy. The second definition of information is the difference between unconditional and conditional entropies. In the present work this latter is used for the definition of the information about states of open systems with various meanings of the control parameter. Two kinds of open systems are considered. The first class of systems concerns those which with zero value of the control parameter are in an equilibrium state. The information on an equilibrium state is equal to zero. During self- organizing in the process of departing from an equilibrium state the information increases. For open systems of this class the conservation law for the sum of the information and entropy with all values of control parameter is proved. In open systems of the second class the equilibrium condition is impossible. For them the concept "norm of a chaoticity" is introduced. It allows to consider two kinds of processes of self-organization and to give the corresponding definitions of information. The statement is carried out on a number of (classical and quantum) examples of physical systems. The example of a medico-biological system also is considered.
1. Open Source in Education
ERIC Educational Resources Information Center
Lakhan, Shaheen E.; Jhunjhunwala, Kavita
2008-01-01
Educational institutions have rushed to put their academic resources and services online, beginning the global community onto a common platform and awakening the interest of investors. Despite continuing technical challenges, online education shows great promise. Open source software offers one approach to addressing the technical problems in…
2. Presto: Open Inquiry!
ERIC Educational Resources Information Center
Hermann, Ronald S.; Miranda, Rommel J.
2010-01-01
Although inquiry-based science teaching has been around since the 1960s, many teachers are slow to incorporate inquiry principles into their science lessons. The authors address this issue by using an analogy between a magician's card trick and open inquiry. This analogy was chosen to portray a difference of perspective and demonstrate how the…
3. The Open Storage Dilemma
ERIC Educational Resources Information Center
Orcutt, Kimberly
2011-01-01
Over the past three decades, open storage facilities have been established at four major museums in order to address the long-standing problem of lack of gallery space for putting collections on view. While making tens of thousands of objects available to visitors represents a great leap forward in accessibility, it raises inherent questions about…
4. Massive and Open
ERIC Educational Resources Information Center
Fasimpaur, Karen
2013-01-01
MOOCs--massive open online courses--are all the rage these days, with hundreds of thousands of participants signing up and investors plunking down millions to get a piece of the pie. Why is there so much excitement about this new disruptive form of online learning, and how does this model apply to professional learning for teachers? Traditional…
5. Openers for Biology Classes.
ERIC Educational Resources Information Center
Gridley, C. Robert R.
This teaching guide contains 200 activities that are suitable for openers and demonstrations in biology classes. Details are provided regarding the use of these activities. Some of the broad topics under which the activities are organized include algae, amphibians, bacteria, biologists, crustaceans, dinosaurs, ecology, evolution, flowering plants,…
6. Open Systems Interconnection.
ERIC Educational Resources Information Center
Denenberg, Ray
1985-01-01
Discusses the need for standards allowing computer-to-computer communication and gives examples of technical issues. The seven-layer framework of the Open Systems Interconnection (OSI) Reference Model is explained and illustrated. Sidebars feature public data networks and Recommendation X.25, OSI standards, OSI layer functions, and a glossary.…
7. Evaluating Open Source Portals
ERIC Educational Resources Information Center
Goh, Dion; Luyt, Brendan; Chua, Alton; Yee, See-Yong; Poh, Kia-Ngoh; Ng, How-Yeu
2008-01-01
Portals have become indispensable for organizations of all types trying to establish themselves on the Web. Unfortunately, there have only been a few evaluative studies of portal software and even fewer of open source portal software. This study aims to add to the available literature in this important area by proposing and testing a checklist for…
8. TIRES, OPEN BURNING
EPA Science Inventory
The chapter describes available information on the health effects from open burning of rubber tires. It concentrates on the three known sources of detailed measurements: (1) a small-scale emissions characterization study performed by the U.S. EPA in a facility designed to simulat...
9. Van: An Open Letter
ERIC Educational Resources Information Center
Tieman, John Samuel
2011-01-01
This essay is an open letter from a classroom teacher to a concerned citizen. The letter lists a variety of problems caused largely by standardization and the more corrosive effects of positivism. Many of these problems are unknown to those outside the immediate school setting. While the letter focuses on a specific setting, an inner city school…
10. Surgical wound care - open
MedlinePlus
Surgical incision care; Open wound care ... your wound again with sutures, you need to care for it at home, since it may take ... Your health care provider will tell you how often to change your dressing . To prepare for the dressing change: Clean your ...
11. An Open Forum Article.
ERIC Educational Resources Information Center
Thieblot, Bernice A.
1990-01-01
Presents an open letter addressed to Morton B. Zuckerman of "U.S. News & World Report" concerning the magazine's survey/article "America's Best Colleges" which received a great deal of public attention. Criticizes the survey for failing to help families make better choices among institutions and failing to encourage colleges to do a better job for…
12. Open G2 strings
NASA Astrophysics Data System (ADS)
de Boer, Jan; de Medeiros, Paul; El-Showk, Sheer; Sinkovics, Annamaria
2008-02-01
We consider an open string version of the topological twist previously proposed for sigma-models with G2 target spaces. We determine the cohomology of open strings states and relate these to geometric deformations of calibrated submanifolds and to flat or anti-self-dual connections on such submanifolds. On associative three-cycles we show that the worldvolume theory is a gauge-fixed Chern-Simons theory coupled to normal deformations of the cycle. For coassociative four-cycles we find a functional that extremizes on anti-self-dual gauge fields. A brane wrapping the whole G2 induces a seven-dimensional associative Chern-Simons theory on the manifold. This theory has already been proposed by Donaldson and Thomas as the higher-dimensional generalization of real Chern-Simons theory. When the G2 manifold has the structure of a Calabi-Yau times a circle, these theories reduce to a combination of the open A-model on special Lagrangians and the open B + B-bar-model on holomorphic submanifolds. We also comment on possible applications of our results.
13. Open Mind Conference
NASA Technical Reports Server (NTRS)
King, Alexander H.
1995-01-01
Open Mind, The Association for the achievement of diversity in higher education, met in conference in Albuquerque, New Mexico, between October 16 and 18, 1992. A number of workgroups met to discuss the goals, structure, and generally evaluate the Association and its achievements. A summary of the workgroup sessions and their minutes are included.
14. Apraxia of lid opening.
PubMed
Ugarte, Marta; Teimory, Masoud
2007-07-01
We describe eyelid movement abnormalities in an 80-year-old man with apraxia of lid opening (ALO), resulting from involuntary levator palpebrae inhibition (ILPI) and pretarsal orbicularis oculi (OO) contraction. He was unable to open his lids at will following closure. Attempted eye opening resulted in forceful contraction of the frontalis muscle, backward thrusting of the head and lengthened lid closure. The inability to reopen the lids was not evident during spontaneous reflex blinking and he had no difficulty in keeping the lids open once they had been manually lifted up. There were no episodes of involuntary drooping of the eyelids or spasmodic contraction of the OO causing involuntary eyelid closure. Pursuit eye movements were not restricted, the vestibulo-ocular reflex was preserved and both horizontal and vertical saccades were normal. Despite the clinically visible persistence of pretarsal OO activity, treatment with botulinum toxin injections in the pretarsal and preseptal portions of the muscle did not reduce his difficulty in initiating lid elevation but he found some benefit using lid crutches. ALO is thought to be due to an abnormality in the supranuclear control of eyelid movement. ILPI can present either isolated or combined with blepharospasm. The excitatory levator palpebrae response necessary to lift the lids up is likely to be in very close connection with the OO antagonistic inhibitory response. Alterations in one or another pre-motor structure may result in inability to raise the lids due to inhibition of the levator palpebrae as well as persistence of the pretarsal OO.
15. APS and Open Access
NASA Astrophysics Data System (ADS)
2011-03-01
The movement toward Open Access continues to gain momentum. A brief review of APS efforts in this area will be presented by APS Editor in Chief, Gene Sprouse. Editors from Physical Review A, B, E, Focus, Letters, and X, Reviews of Modern Physics, and Physics will address your questions about publishing in this evolving environment.
16. Open Educational Resources
ERIC Educational Resources Information Center
McShane, Michael Q.
2017-01-01
While digital products have made significant inroads into the educational resources market, textbooks and other print materials still command about 60 percent of sales. But whether print or digital, all of these commercial offerings now face threats from a burgeoning effort to promote "open" resources for education--that is, materials…
17. Through-Wall Imaging Radar
DTIC Science & Technology
2012-01-01
receiver dynamic range to be applied to the target scene behind the wall. A time-division multiplexed ( TDM ), multiple-input, multiple-output (MIMO...by the data-acquisition computer. The TDM MIMO radar system sequences through each of the 44 bistatic combinations, acquiring one range profile at...96 5. 75 5. 75 2 FiGurE 5. In this cartoon of the time-division multiplexed ( TDM ), multiple-input, multiple-output (MIMO) array lay- out [compare to
18. An improved resistive wall monitor
SciTech Connect
Fellenz, Brian; Crisp, Jim
1998-12-10
Resistive wall monitors were designed and built for the Fermilab Main Injector project. These devices measure longitudinal beam current from 3 KHz to 4 GHz with a 1 ohm gap impedance. The new design provides a larger aperture and a calibration port to improve the accuracy of single-bunch intensity measurements. Microwave absorber material is used to reduce interference from spurious electromagnetic waves traveling inside the beam pipe. Several types of ferrite materials were evaluated for the absorber. Inexpensive ferrite rods were selected and assembled in an array forming the desired geometry without machining.
19. Wall interference assessment and corrections
NASA Technical Reports Server (NTRS)
Newman, P. A.; Kemp, W. B., Jr.; Garriz, J. A.
1989-01-01
Wind tunnel wall interference assessment and correction (WIAC) concepts, applications, and typical results are discussed in terms of several nonlinear transonic codes and one panel method code developed for and being implemented at NASA-Langley. Contrasts between 2-D and 3-D transonic testing factors which affect WIAC procedures are illustrated using airfoil data from the 0.3 m Transonic Cryogenic Tunnel and Pathfinder 1 data from the National Transonic Facility. Initial results from the 3-D WIAC codes are encouraging; research on and implementation of WIAC concepts continue.
20. Workshop on First Wall Coating
NASA Astrophysics Data System (ADS)
Kamada, K.; Fukutomi, M.
1982-03-01
Impurity control and first wall design in the JT 60 long pulse Tokamak is discussed. The present state of coating technology in Japan is reviewed with emphasis on fabrication methods and the characterization of thin coated films available by plasma spraying and chemical and physical vapor deposition. Surface preparation, radiation damage, internal stress, crystal structure and bonding are considered as well as the application of silicon carbide, titanium nitride, titanium carbide, titanium boride, and chromium nitride coatings by magnetron sputtering, long plating, electron beam evaporation, and gas absorption and reactive r.f. sputtering.
1. Moving walls and geometric phases
NASA Astrophysics Data System (ADS)
Facchi, Paolo; Garnero, Giancarlo; Marmo, Giuseppe; Samuel, Joseph
2016-09-01
We unveil the existence of a non-trivial Berry phase associated to the dynamics of a quantum particle in a one dimensional box with moving walls. It is shown that a suitable choice of boundary conditions has to be made in order to preserve unitarity. For these boundary conditions we compute explicitly the geometric phase two-form on the parameter space. The unboundedness of the Hamiltonian describing the system leads to a natural prescription of renormalization for divergent contributions arising from the boundary.
2. The OSG open facility: A sharing ecosystem
DOE PAGES
Jayatilaka, B.; Levshina, T.; Rynge, M.; ...
2015-12-23
The Open Science Grid (OSG) ties together individual experiments’ computing power, connecting their resources to create a large, robust computing grid, this computing infrastructure started primarily as a collection of sites associated with large HEP experiments such as ATLAS, CDF, CMS, and DZero. In the years since, the OSG has broadened its focus to also address the needs of other US researchers and increased delivery of Distributed High Through-put Computing (DHTC) to users from a wide variety of disciplines via the OSG Open Facility. Presently, the Open Facility delivers about 100 million computing wall hours per year to researchers whomore » are not already associated with the owners of the computing sites, this is primarily accomplished by harvesting and organizing the temporarily unused capacity (i.e. opportunistic cycles) from the sites in the OSG. Using these methods, OSG resource providers and scientists share computing hours with researchers in many other fields to enable their science, striving to make sure that these computing power used with maximal efficiency. Furthermore, we believe that expanded access to DHTC is an essential tool for scientific innovation and work continues in expanding this service.« less
3. The OSG open facility: A sharing ecosystem
SciTech Connect
Jayatilaka, B.; Levshina, T.; Rynge, M.; Sehgal, C.; Slyz, M.
2015-12-23
The Open Science Grid (OSG) ties together individual experiments’ computing power, connecting their resources to create a large, robust computing grid, this computing infrastructure started primarily as a collection of sites associated with large HEP experiments such as ATLAS, CDF, CMS, and DZero. In the years since, the OSG has broadened its focus to also address the needs of other US researchers and increased delivery of Distributed High Through-put Computing (DHTC) to users from a wide variety of disciplines via the OSG Open Facility. Presently, the Open Facility delivers about 100 million computing wall hours per year to researchers who are not already associated with the owners of the computing sites, this is primarily accomplished by harvesting and organizing the temporarily unused capacity (i.e. opportunistic cycles) from the sites in the OSG. Using these methods, OSG resource providers and scientists share computing hours with researchers in many other fields to enable their science, striving to make sure that these computing power used with maximal efficiency. Furthermore, we believe that expanded access to DHTC is an essential tool for scientific innovation and work continues in expanding this service.
4. The OSG open facility: A sharing ecosystem
NASA Astrophysics Data System (ADS)
Jayatilaka, B.; Levshina, T.; Rynge, M.; Sehgal, C.; Slyz, M.
2015-12-01
The Open Science Grid (OSG) ties together individual experiments’ computing power, connecting their resources to create a large, robust computing grid; this computing infrastructure started primarily as a collection of sites associated with large HEP experiments such as ATLAS, CDF, CMS, and DZero. In the years since, the OSG has broadened its focus to also address the needs of other US researchers and increased delivery of Distributed High Through-put Computing (DHTC) to users from a wide variety of disciplines via the OSG Open Facility. Presently, the Open Facility delivers about 100 million computing wall hours per year to researchers who are not already associated with the owners of the computing sites; this is primarily accomplished by harvesting and organizing the temporarily unused capacity (i.e. opportunistic cycles) from the sites in the OSG. Using these methods, OSG resource providers and scientists share computing hours with researchers in many other fields to enable their science, striving to make sure that these computing power used with maximal efficiency. We believe that expanded access to DHTC is an essential tool for scientific innovation and work continues in expanding this service.
5. Open-cell glass crystalline porous material
DOEpatents
Anshits, Alexander G.; Sharonova, Olga M.; Vereshchagina, Tatiana A.; Zykova, Irina D.; Revenko, Yurii A.; Tretyakov, Alexander A.; Aloy, Albert S.; Lubtsev, Rem I.; Knecht, Dieter A.; Tranter, Troy J.; Macheret, Yevgeny
2002-01-01
An open-cell glass crystalline porous material made from hollow microspheres which are cenospheres obtained from fly ash, having an open-cell porosity of up to 90 vol. % is produced. The cenospheres are separated into fractions based on one or more of grain size, density, magnetic or non-magnetic, and perforated or non-perforated. Selected fractions are molded and agglomerated by sintering with a binder at a temperature below the softening temperature, or without a binder at a temperature about, or above, the softening temperature but below the temperature of liquidity. The porous material produced has an apparent density of 0.3-0.6 g/cm.sup.3, a compressive strength in the range of 1.2-3.5 MPa, and two types of openings: through-flow wall pores in the cenospheres of 0.1-30 micrometers, and interglobular voids between the cenospheres of 20-100 micrometers. The porous material of the invention has properties useful as porous matrices for immobilization of liquid radioactive waste, heat-resistant traps and filters, supports for catalysts, adsorbents and ion-exchangers.
6. Open-cell glass crystalline porous material
DOEpatents
Anshits, Alexander G.; Sharonova, Olga M.; Vereshchagina, Tatiana A.; Zykova, Irina D.; Revenko, Yurii A.; Tretyakov, Alexander A.; Aloy, Albert S.; Lubtsev, Rem I.; Knecht, Dieter A.; Tranter, Troy J.; Macheret, Yevgeny
2003-12-23
An open-cell glass crystalline porous material made from hollow microspheres which are cenospheres obtained from fly ash, having an open-cell porosity of up to 90 vol. % is produced. The cenospheres are separated into fractions based on one or more of grain size, density, magnetic or non-magnetic, and perforated or non-perforated. Selected fractions are molded and agglomerated by sintering with a binder at a temperature below the softening temperature, or without a binder at a temperature about, or above, the softening temperature but below the temperature of liquidity. The porous material produced has an apparent density of 0.3-0.6 g/cm.sup.3, a compressive strength in the range of 1.2-3.5 MPa, and two types of openings: through-flow wall pores in the cenospheres of 0.1-30 micrometers, and interglobular voids between the cenospheres of 20-100 micrometers. The porous material of the invention has properties useful as porous matrices for immobilization of liquid radioactive waste, heat-resistant traps and filters, supports for catalysts, adsorbents and ion-exchangers.
7. INTERIOR VIEW OF LIVING ROOM. NOTE THE OPENING FOR AN ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
INTERIOR VIEW OF LIVING ROOM. NOTE THE OPENING FOR AN AIR CONDITIONER ON THE FAR WALL AND THE SLIDING DOORS TO THE DINING ROOM ON THE LEFT. VIEW FACING SOUTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, U-Shaped Two-Bedroom Single-Family Type 6, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI
8. Advanced Extended Plate and Beam Wall System in a Cold-Climate House
SciTech Connect
Mallay, Dave; Wiehagen, Joseph; Kochkin, Vladimir
2016-01-29
This report presents the design and evaluation of an innovative wall system. This highly insulated (high-R) light-frame wall system for use above grade in residential buildings is referred to as Extended Plate & Beam (EP&B). The EP&B design is the first of its kind to be featured in a new construction test house (NCTH) for the DOE Building America program. The EP&B wall design integrates standard building methods and common building products to construct a high-R wall that minimizes transition risks and costs to builders. The EP&B design combines optimized framing with integrated rigid foam sheathing to increase the wall system's R-value and reduce thermal bridging. The foam sheathing is installed between the wall studs and structural wood sheathing. The exterior wood sheathing is attached directly to a framing extension formed by extended top and bottom plates. The exterior wood sheathing can dry to the exterior and provides bracing, a clear drainage plane and flashing surface for window and door openings, and a nailing surface for siding attachment. With support of the DOE Building America program, Home Innovation Research Labs partnered with Lancaster County Career and Technology Center (LCCTC) to build a NCTH in Lancaster, PA to demonstrate the EP&B wall design in a cold climate (IECC climate zone 5A). The results of the study confirmed the benefits of the systems and the viability of its integration into the house construction process.
9. Technology Solutions Case Study: Monitoring of Double Stud Wall Moisture Conditions in the Northeast, Devens, Massachusetts
SciTech Connect
2015-03-01
Double stud walls have a higher risk of interior-sourced condensation moisture damage when compared with high-R approaches using exterior insulating sheathing. In this project, Building Science Corporation monitored moisture conditions in double-stud walls from 2011 through 2014 at a new production house located in Devens, Massachusetts. The builder, Transformations, Inc., has been using double-stud walls insulated with 12 in. of open cell polyurethane spray foam (ocSPF); however, the company has been considering a change to netted and blown cellulose insulation for cost reasons. Cellulose is a common choice for double-stud walls because of its lower cost (in most markets). However, cellulose is an air-permeable insulation, unlike spray foams, which increases interior moisture risks. The team compared three double-stud assemblies: 12 in. of ocSPF, 12 in. of cellulose, and 5-½ in. of ocSPF at the exterior of a double-stud wall (to approximate conventional 2 × 6 wall construction and insulation levels, acting as a control wall). These assemblies were repeated on the north and south orientations, for a total of six assemblies.
10. Growth and Remodeling in a Thick-Walled Artery Model: Effects of Spatial Variations in Wall Constituents
PubMed Central
Alford, Patrick W.; Humphrey, Jay D.; Taber, Larry A.
2008-01-01
A mathematical model is presented for growth and remodeling of arteries. The model is a thick-walled tube composed of a constrained mixture of smooth muscle cells, elastin and collagen. Material properties and radial and axial distributions of each constituent are prescribed according to previously published data. The analysis includes stress-dependent growth and contractility of the muscle and turnover of collagen fibers. Simulations were conducted for homeostatic conditions and for the temporal response following sudden hypertension. Numerical pressure-radius relations and opening angles (residual stress) show reasonable agreement with published experimental results. In particular, for realistic material and structural properties, the model predicts measured variations in opening angles along the length of the aorta with reasonable accuracy. These results provide a better understanding of the determinants of residual stress in arteries and could lend insight into the importance of constituent distributions in both natural and tissue-engineered blood vessels. PMID:17786493
11. Spontaneous Behaviors and Wall-Curvature Lead to Apparent Wall Preference in Planarian.
PubMed
Akiyama, Yoshitaro; Agata, Kiyokazu; Inoue, Takeshi
2015-01-01
The planarian Dugesia japonica tends to stay near the walls of its breeding containers and experimental dishes in the laboratory, a phenomenon called "wall preference". This behavior is thought to be important for environmental adaptation, such as hiding by planarians in nature. However, the mechanisms regulating wall-preference behavior are not well understood, since this behavior occurs in the absence of any particular stimulation. Here we show the mechanisms of wall-preference behavior. Surprisingly, planarian wall-preference behavior was also shown even by the head alone and by headless planarians. These results indicate that planarian "wall-preference" behavior only appears to be a "preference" behavior, and is actually an outcome of spontaneous behaviors, rather than of brain function. We found that in the absence of environmental cues planarians moved basically straight ahead until they reached a wall, and that after reaching a wall, they changed their direction of movement to one tangential to the wall, suggesting that this spontaneous behavior may play a critical role in the wall preference. When we tested another spontaneous behavior, the wigwag movement of the planarian head, using computer simulation with various wigwag angles and wigwag intervals, large wigwag angle and short wigwag interval reduced wall-preference behavior. This indicated that wigwag movement may determine the probability of staying near the wall or leaving the wall. Furthermore, in accord with this simulation, when we tested planarian wall-preference behavior using several assay fields with different curvature of the wall, we found that concavity and sharp curvature of walls negatively impacted wall preference by affecting the permissible angle of the wigwag movement. Together, these results indicate that planarian wall preference may be involuntarily caused by the combination of two spontaneous planarian behaviors: moving straight ahead until reaching a wall and then moving along it
12. Spontaneous Behaviors and Wall-Curvature Lead to Apparent Wall Preference in Planarian
PubMed Central
Akiyama, Yoshitaro; Agata, Kiyokazu; Inoue, Takeshi
2015-01-01
The planarian Dugesia japonica tends to stay near the walls of its breeding containers and experimental dishes in the laboratory, a phenomenon called “wall preference”. This behavior is thought to be important for environmental adaptation, such as hiding by planarians in nature. However, the mechanisms regulating wall-preference behavior are not well understood, since this behavior occurs in the absence of any particular stimulation. Here we show the mechanisms of wall-preference behavior. Surprisingly, planarian wall-preference behavior was also shown even by the head alone and by headless planarians. These results indicate that planarian “wall-preference” behavior only appears to be a “preference” behavior, and is actually an outcome of spontaneous behaviors, rather than of brain function. We found that in the absence of environmental cues planarians moved basically straight ahead until they reached a wall, and that after reaching a wall, they changed their direction of movement to one tangential to the wall, suggesting that this spontaneous behavior may play a critical role in the wall preference. When we tested another spontaneous behavior, the wigwag movement of the planarian head, using computer simulation with various wigwag angles and wigwag intervals, large wigwag angle and short wigwag interval reduced wall-preference behavior. This indicated that wigwag movement may determine the probability of staying near the wall or leaving the wall. Furthermore, in accord with this simulation, when we tested planarian wall-preference behavior using several assay fields with different curvature of the wall, we found that concavity and sharp curvature of walls negatively impacted wall preference by affecting the permissible angle of the wigwag movement. Together, these results indicate that planarian wall preference may be involuntarily caused by the combination of two spontaneous planarian behaviors: moving straight ahead until reaching a wall and then
13. POWs: Physicists on Wall Street
SciTech Connect
Derman, Emanuel
2006-10-30
Quantitative financial modeling seems to employ both the language and techniques of physics, but how similar are the two disciplines in theory and practice? This talk discusses the move from physics to finance, the nature of financial modeling and its deceptive similarity with theoretical physics, what it's like to work in the financial arena, and some of the open problems of interest.
14. Opening Reproducible Research
NASA Astrophysics Data System (ADS)
Nüst, Daniel; Konkol, Markus; Pebesma, Edzer; Kray, Christian; Klötgen, Stephanie; Schutzeichel, Marc; Lorenz, Jörg; Przibytzin, Holger; Kussmann, Dirk
2016-04-01
Open access is not only a form of publishing such that research papers become available to the large public free of charge, it also refers to a trend in science that the act of doing research becomes more open and transparent. When science transforms to open access we not only mean access to papers, research data being collected, or data being generated, but also access to the data used and the procedures carried out in the research paper. Increasingly, scientific results are generated by numerical manipulation of data that were already collected, and may involve simulation experiments that are completely carried out computationally. Reproducibility of research findings, the ability to repeat experimental procedures and confirm previously found results, is at the heart of the scientific method (Pebesma, Nüst and Bivand, 2012). As opposed to the collection of experimental data in labs or nature, computational experiments lend themselves very well for reproduction. Some of the reasons why scientists do not publish data and computational procedures that allow reproduction will be hard to change, e.g. privacy concerns in the data, fear for embarrassment or of losing a competitive advantage. Others reasons however involve technical aspects, and include the lack of standard procedures to publish such information and the lack of benefits after publishing them. We aim to resolve these two technical aspects. We propose a system that supports the evolution of scientific publications from static papers into dynamic, executable research documents. The DFG-funded experimental project Opening Reproducible Research (ORR) aims for the main aspects of open access, by improving the exchange of, by facilitating productive access to, and by simplifying reuse of research results that are published over the Internet. Central to the project is a new form for creating and providing research results, the executable research compendium (ERC), which not only enables third parties to
15. Speech About the Great Wall
NASA Astrophysics Data System (ADS)
Yang, Chen Ning
2013-05-01
Of all the sights that I saw during that trip, the one that provoked the most thought on my part was the Great Wall. The Great Wall defies imagination. It is simple and strong. It winds gracefully up and down. It scales slowly but steadily the distant hill, to disappear down into the valley beyond, only to climb again, inexorably, to surmount the next mountain in its path. As one examines the individual stones with which it was built, one realizes how much sweat and blood there must have been in its complex history. As one looks at the overall structure, at its strength and elegance, its real significance begins to emerge. It is long. It is tenacious. It is flexible in every turn, but is persistent and persisting in the long range development. Its overall unity of purpose is what gives it strength and character. And its overall unity of purpose is what makes it one of the man-made structures on the surface of the earth to become first visible to a visitor approaching our planet from outer space...
16. [Ageing of the arterial wall].
PubMed
Hanon, O
2006-11-01
Several mechanisms are implicated in the arterial wall changes due to ageing: ageing, hypertension and atherosclerosis. Although the changes related to ageing (arteriosclerosis) have many factors in common with those induced by hypertension, they differ from those caused by atherosclerosis although commonly associated. Arteriosclerosis causes a diffuse increase of the rigidity of the large arteries by disease of the media, the main clinical manifestation of which is the increase in pulsed pressure. This arterial "hyperpulsability" contributes to a defect in coupling between the heart and the blood vessels which results in an increase in the pulsatile load of the left ventricle and to left ventricular hypertrophy and decreased coronary perfusion. Atherosclerosis seems more of a localised scarring phenomenon of the arterial wall which is exposed to a series of chronic aggressions characterised by deposits of lipids in the intima and whose main complication is thrombosis. Although these two processes may be associated, or interact one with the other, they are clearly different in nature. Therefore, atherosclerosis is a localised disease resulting in a decrease in arterial lumen, quite different from arteriosclerosis which is a diffuse, physiological condition which leads to an increase in the arterial lumen.
17. Moss cell walls: structure and biosynthesis
PubMed Central
Roberts, Alison W.; Roberts, Eric M.; Haigler, Candace H.
2012-01-01
The genome sequence of the moss Physcomitrella patens has stimulated new research examining the cell wall polysaccharides of mosses and the glycosyl transferases that synthesize them as a means to understand fundamental processes of cell wall biosynthesis and plant cell wall evolution. The cell walls of mosses and vascular plants are composed of the same classes of polysaccharides, but with differences in side chain composition and structure. Similarly, the genomes of P. patens and angiosperms encode the same families of cell wall glycosyl transferases, yet, in many cases these families have diversified independently in each lineage. Our understanding of land plant evolution could be enhanced by more complete knowledge of the relationships among glycosyl transferase functional diversification, cell wall structural and biochemical specialization, and the roles of cell walls in plant adaptation. As a foundation for these studies, we review the features of P. patens as an experimental system, analyses of cell wall composition in various moss species, recent studies that elucidate the structure and biosynthesis of cell wall polysaccharides in P. patens, and phylogenetic analysis of P. patens genes potentially involved in cell wall biosynthesis. PMID:22833752
18. Lignin variability in plant cell walls: contribution of new models.
PubMed
Neutelings, Godfrey
2011-10-01
Lignin is a major component of certain plant cell walls. The enzymes and corresponding genes associated with the metabolic pathway leading to the production of this complex phenolic polymer have been studied for many years now and are relatively well characterized. The use of genetically modified model plants (Arabidopsis, tobacco, poplar.) and mutants has contributed greatly to our current understanding of this process. The recent utilisation and/or development of a number of dedicated genomic and transcriptomic tools for other species opens new perspectives for advancing our knowledge of the biological role of this important polymer in less typical situations and/or species. In this context, studies on the formation of hypolignified G-type fibres in angiosperm tension wood, and the natural hypolignification of secondary cell walls in plant bast fibre species such as hemp (Cannabis sativa), flax (Linum usitatissimum) or ramie (Boehmeria nivea) are starting to provide novel information about how plants control secondary cell wall formation. Finally, other biologically interesting species for which few molecular resources currently exist could also represent interesting future models.
19. The State of the GeoWall
NASA Astrophysics Data System (ADS)
Morin, P. J.; Leigh, J.; van Keken, P.; Johnson, A.
2003-12-01
The GeoWall stereo projection technology has been widely adopted within Earth Science. Over 20,000 undergraduate students per year use a GeoWall in classroom and lab settings at over 80 institutions around the world using over 200 GeoWalls. We believe that critical mass for this technology has been reached in the Earth Science. Many collaborations have been initiated. With Iris, GeoWall is exploring new ways to monitor seismic networks in real-time and to visualize extremely large, whole Earth seismic simulations. We are also working with a number of drilling organizations including JOI, DOSECC and LacCore to bring modern visualization technology to core interpretation and drill site selection. Also, over 15 museums now have or are building GeoWalls for informal education. Much of the science that is being performed on the GeoWall is finding its way directly into the classroom and science museum. One of the success stories has been the GeoWall Consortium's interaction with industry. The basic hardware for the GeoWall has been spun off to companies that now sell variations of the hardware. In addition, many software companies including ESRI and Dynamic Graphics have added support for the GeoWall in their products. The future of GeoWall is four fold. Curriculum development will bring more material to all GeoWall users. Assessment of the curriculum and educational psychology will give us GeoWall best practices. In technology development, the GeoWall 2 is a 20+ million pixel, tiled display which brings more resolution to the Earth Sciences than ever. To support research the consortium is developing a volume rendering application to visualize extremely large datasets.
20. Architecture of dermatophyte cell Walls: Electron microscopic and biochemical analysis
NASA Technical Reports Server (NTRS)
Nozawa, Y.; Kitajima, Y.
1984-01-01
A review with 83 references on the cell wall structure of dermatophytes is presented. Topics discussed include separation and preparation of cell walls; microstructure of cell walls by electron microscopy; chemical composition of cell walls; structural model of cell walls; and morphological structure of cell walls.
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http://mathhelpforum.com/advanced-statistics/152054-probability-involving-z-score-print.html
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# probability involving z-score
Printable View
• July 26th 2010, 07:45 PM
Jskid
[RESOLVED]probability involving z-score
A bottling company uses a machine to fill plastic bottles with pop. Due to variations in the filling process, the pop amounts in all bottles are normally distributed with a mean of 300 ml and a standard deviation of 3 ml. One bottle is randomly selected, what is the probability that bottle contains less than 299.5 ml?
$z=\frac{299.5-300}{\frac{3}{\sqrt{n}}}$ I'm not sure what value n is, or if it's needed.
I think I'm suppose to take n=1.
For this question how I'm calculating the probability do I write $P(\bar{x}<299.5)$ or $P(x<299.5)$?
• July 26th 2010, 09:20 PM
mr fantastic
Quote:
Originally Posted by Jskid
A bottling company uses a machine to fill plastic bottles with pop. Due to variations in the filling process, the pop amounts in all bottles are normally distributed with a mean of 300 ml and a standard deviation of 3 ml. One bottle is randomly selected, what is the probability that bottle contains less than 299.5 ml?
$z=\frac{299.5-300}{\frac{3}{\sqrt{n}}}$ I'm not sure what value n is, or if it's needed.
Where has n come from? $\displaystyle z = \frac{x - \mu}{\sigma}$ and you have been told the values of mean, sd and x.
• July 27th 2010, 06:26 PM
Jskid
$\sigma_{\bar{x}}=\frac{\sigma}{\sqrt{n}}$ where n is sample size.
What I don't understand is a remeber doing similar questions but just used the S.D. $\sigma$
• July 27th 2010, 06:42 PM
pickslides
Quote:
Originally Posted by Jskid
$\sigma_{\bar{x}}=\frac{\sigma}{\sqrt{n}}$ where n is sample size.
What I don't understand is a remeber doing similar questions but just used the S.D. $\sigma$
$P(\bar{X}<299.5) \implies P\left(Z<\frac{\bar{X}-\mu}{\frac{\sigma}{\sqrt{n}}}\right)$
$P(X<299.5) \implies P(Z<\frac{X-\mu}{\sigma})$
Can you see the difference?
• July 27th 2010, 08:22 PM
Jskid
Quote:
Originally Posted by pickslides
$P(\bar{X}<299.5) \implies P\left(Z<\frac{\bar{X}-\mu}{\frac{\sigma}{\sqrt{n}}}\right)$
$P(X<299.5) \implies P(Z<\frac{X-\mu}{\sigma})$
Can you see the difference?
I think I understand. The top equation is for the probability of a sample mean and the lower one is for the probability of getting a sample of a certain value? Does that mean the two formula are the same because $\frac{\bar{X}-\mu}{\frac{\sigma}{\sqrt{n}}}=\frac{\bar{X}-\mu}{\frac{\sigma}{\sqrt{1}}}=\frac{X-\mu}{\frac{\sigma}{1}}$
• July 27th 2010, 10:18 PM
pickslides
Quote:
Originally Posted by Jskid
I think I understand. The top equation is for the probability of a sample mean and the lower one is for the probability of getting a sample of a certain value? Does that mean the two formula are the same because $\frac{\bar{X}-\mu}{\frac{\sigma}{\sqrt{n}}}=\frac{\bar{X}-\mu}{\frac{\sigma}{\sqrt{1}}}=\frac{X-\mu}{\frac{\sigma}{1}}$
I have never thought of it like that. But I am inclinded to say this is not true as you can be given a sample size $n>1$ for $X$ and the standard tranformation would apply given it was normal.
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|
http://blog.mpg.is/2014/12/proper-tail-recursion-in-python.html
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## Sunday, December 21, 2014
### Proper tail recursion in Python and Hy
I recently came across a new language, Hy. It is a Lisp dialect of Python! This means that I can finally start programming as I want in a functional language, Lisp, and not have to worry about whether others can use my code or whether I hit a snag that I can't figure out in lisp, as I can always drop back down to Python if necessary.
Anyways, since it is a Lisp dialect, I wished that it had proper tail recursion, as I utilize tail recursion a lot when programming in Lisp, and hitting a maximum recursion depth exception is quite common for me. As proper tail recursion is missing in Python, I first had to implement tail recursion in Python . I did this using a decorator and an exception, which allows me to bail out of a function without returning anything, and the decorator tries to return from the function and catches these TailCall exceptions, and handles them so that it all works. This is probably a lot slower way of doing it than having it implemented in the interpreter itself, but seeing as you gain instead power to go much deeper in recursion, I think it is a fair trade-off.
The next step was implementing the decorator and exception in Hy. The tail recursion decorator and exception in Hy is a bit awkward, but works well enough.
The final step was implementing it in Hy itself, and I now have a pending pull request for the change. The implementation adds a new import,
(import [__future__ [TailRec]])
which the Hy compiler recognizes and turns on tail recursion during the compilation. This adds the decorator around every function that uses tail recursion, and switches the return statements for raising of the TailCall exception. This effectively gives us proper tail recursion in Hy!
This allows us to do things like:
(defn tcodd [n]
(if (= n 0)
False
(tceven (- n 1))))
(defn tceven [n]
(if (= n 0)
True
(tcodd (- n 1))))
(print (tceven 1000))
and
(defn fact [n]
(defn facthelper [n acc]
(if (= n 0)
acc
(facthelper (- n 1) (* n acc))))
(facthelper n 1))
(print (fact 1000))
without ever hitting the recursion depth exceeded exception! Woo!
Here's hoping that it makes it into Hy!
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http://tex.stackexchange.com/questions/69223/long-title-runs-off-page
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# Long title runs off page
I'm making a graph in using `gnuplot` and have converted the `eps` to `pdf`, so I have `.tex` file and `pdf` file. Usual they are great except this time the title in the title runs off the page, the title is a line of the `.tex` file.
`````` \put(3940,4709){\makebox(0,0){\strut{}REALLY LONG TITLE, REALLY LONG TITLE, REALLY LONG TITLE, REALLY LONG TITLE, REALLY LONG TITLE, REALLY LONG TITLE}}%
``````
I've tried using "\n" but pdflatex compiler doesn't like this argument.
`````` \put(3940,4709){\makebox(0,0){\strut{}REALLY LONG TITLE, REALLY LONG TITLE, REALLY LONG TITLE,\n REALLY LONG TITLE, REALLY LONG TITLE, REALLY LONG TITLE}}%
``````
Does anyone have any ideas?
-
`\parbox{desired width}{REALLY LONG TITLE …}` instead of the `\makebox`? – Qrrbrbirlbel Aug 29 '12 at 1:18
I will try that when I get home from work. and if it doesn't work I'll try an upload an example. – Joshua Siret Aug 29 '12 at 6:45
! Illegal unit of measure (pt inserted). <to be read again> \relax l.115 \gplbacktext I've started to get this error – Joshua Siret Aug 29 '12 at 18:59
How do I make code in comments? – Joshua Siret Aug 29 '12 at 19:03
@JoshuaSiret: If you indent lines by 4 spaces or enclose words in backticks ```, they'll be marked as code. – Werner Aug 29 '12 at 20:36
``````\put(3940,5009){\makebox(0,0){\strut{}REALLY LONG TITLE, REALLY LONG TITLE, REALLY LONG TITLE,}}%
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http://mathhelpforum.com/calculus/143233-complex-integration-print.html
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# Complex Integration
• May 5th 2010, 12:18 PM
zizou1089
Complex Integration
How would I compute:
$I=\int_{2\pi }^{0}\frac{4d\theta }{2 cos\theta + 3 sin\theta + 2i}$
I have tried finding the poles by changing the values into complex values
where $z=e^{i\theta }$
$2cos\theta =z+\frac{1}{z}$
$2sin\theta =-i({z-\frac{1}{z}})$
I have concluded
$I=\oint \frac{\frac{4dz}{iz}}{(z+\frac{1}{z})-\frac{3i}{2}(z-\frac{1}{z})+2i}$
Could someone tell me if this correct and I cant find the poles cause I cant find anyway of factorising! Thanks in advance!
• May 5th 2010, 02:18 PM
ques
Quote:
Originally Posted by zizou1089
How would I compute:
$I=\int_{2\pi }^{0}\frac{4d\theta }{2 cos\theta + 3 sin\theta + 2i}$
$=> I= - \int_{0}^{2\pi}\frac{4d\theta }{2 cos\theta + 3 sin\theta + 2i}$
I have tried finding the poles by changing the values into complex values
where $z=e^{i\theta }$
$2cos\theta =z+\frac{1}{z}$
$2sin\theta =-i({z-\frac{1}{z}})$
I have concluded
$I=-\oint \frac{\frac{4dz}{iz}}{(z+\frac{1}{z})-\frac{3i}{2}(z-\frac{1}{z})+2i}$
Could someone tell me if this correct and I cant find the poles cause I cant find anyway of factorising! Thanks in advance!
Multiply iz with the denominator.
Simplifying will give us the denominator's expression as,
( 3 + 2i ) z^2 - 4 z + ( 2i - 3 )
Now you should be able to figure out the compex roots quite easily.(Happy)
• May 5th 2010, 03:19 PM
zizou1089
Quote:
Originally Posted by ques
Multiply iz with the denominator.
Simplifying will give us the denominator's expression as,
( 3 + 2i ) z^2 - 4 z + ( 2i - 3 ) = 0
Now you should be able to figure out the compex roots quite easily.(Happy)
Thats the bit Im stuck on (Worried)..
• May 5th 2010, 03:21 PM
Bruno J.
Quote:
Originally Posted by zizou1089
Thats the bit Im stuck on (Worried)..
Do you know the quadratic formula?
• May 5th 2010, 03:25 PM
ques
Consider ( 3 + 2i ) z^2 - 4 z + ( 2i - 3 ) = 0
For a(z^2) + bz + c = 0 the roots are
z = {-b +- (b^2 - 4ac)^(1/2) }/2a
Here z = [ 4 +- {16 - ( 2i - 3 ) (2i + 3) }]/ {2(2i + 3)}
You should be able to take it on from here.
• May 5th 2010, 03:27 PM
ques
Quote:
Originally Posted by Bruno J.
Do you know the quadratic formula?
I am new here and I am sorry that I gave out way too much!
• May 5th 2010, 03:48 PM
zizou1089
Yep got it with the quadratic formula, problem is sometimes using the formula i get a complex number within the square root, and the function cannot be factorised either, so is there a more consistent way of getting the roots??
• May 5th 2010, 03:51 PM
ques
Quote:
Originally Posted by zizou1089
Yep got it with the quadratic formula, problem is sometimes using the formula i get a complex number within the square root, and the function cannot be factorised either, so is there a more consistent way of getting the roots??
Why do you think that i^(1/5) or that ( i + 1)^(1/35) does not exist ?
• May 5th 2010, 04:15 PM
Bruno J.
Quote:
Originally Posted by ques
I am new here and I am sorry that I gave out way too much!
No worries mate, welcome aboard! (Clapping)
|
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https://cracku.in/6-select-the-set-that-does-not-belong-in-the-followi-x-rrb-alp-29th-aug-2018-shift-3
|
Question 6
# Select the set that does NOT belong in the following group of sets.(2, 14, 16), ( 6, 30, 36), (5, 35, 40), (3, 21, 24)
Solution
The pattern in the triplet is :
$$(x , x \times 7, x \times 8 )$$
While$$( 6, 30, 36) = ( 6, 6 \times 5, 6 \times 6)$$ is odd one.
So , the answer would be Option c)( 6, 30, 36).
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http://seekquarry.com/p/Coding
|
# Coding Guidelines for the Yioop
## Introduction
In order to understand a software project, it helps to understand its organization and conventions. To encourage people to dive in and help improve Yioop, and to ensure contributions which are easily understood within the context of Yioop's current standards, this article describes the coding conventions, issue tracking, and commit process for Yioop. It first describes the coding styles to be used for various languages within Yioop. It then describes some guidelines for what kind of code should go into which kind of files in Yioop. Finally, it concludes with a discussion of how issues should be submitted to the issue tracker, how to make patches for Yioop, and how commit messages should be written.
## General
1. One of the design goals of Yioop was to minimize dependencies on other projects and libraries. When coming up with a solution to a problem preference should be given to solutions which do not introduce new dependencies on external projects or libraries. Also, one should be on the lookout for eliminating existing dependencies, configuration requirements, etc.
2. The coding language for Yioop is English. This means all comments within the source code should be in English.
3. All data that will be written to the web interface should be localizable. That means easily translatable to any text representation of a human language. The section on localization discusses facilities in Yioop for doing this.
4. Information written as log messages to log files and profiling information about queries (made available by the query info checkbox in Configure), which are not intended for end-users, do not need to be localized.
5. Project file names should be lowercase words. Non-PHP, multi-word file names should separate words with an underscore. For example, default_crawl.ini
6. To facilitate autoloading, all PHP files names should be camel-cased starting with a upper-case letter. For example, AdminView.php
7. Each project file should begin with the GPL3 license as a comment in the appropriate format for the file in question. For example, for a PHP file, this might look like:
/**
* SeekQuarry/Yioop --
* Open Source Pure PHP Search Engine, Crawler, and Indexer
*
* Copyright (C) 2009 - 2020 Chris Pollett [email protected]
*
* LICENSE:
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*
* END LICENSE
*
* @author Chris Pollett [email protected]
* @package seek_quarry
* @subpackage executables
* @license http://www.gnu.org/licenses/ GPL3
* @link http://www.seekquarry.com/
* @copyright 2009 - 2014
* @filesource
*/
Here the subpackage might vary.
8. All non-binary files in Yioop should be UTF-8 encoded. Files should not have a byte order mark.
9. All non-binary files in Yioop should follow the convention of using four spaces for tabs (rather than tab characters). Further, all lines should be less than or equal to 80 columns in length. Lines should not end with trailing white-space characters. It is recommended to use an editor which can display white-space characters and which can display a bar marking the 80th column. For example, one can use gEdit or vim.
10. One should use one space before and after assignment, boolean, binary, and comparison operators. A single space should be used after, but not before, commas and semi-colons. A space should not be used before increment, decrement, and sign operators:
if ($i == 0 &&$j > 5 * $x) { /* some statements*/}$i = 7;
$i += 3;$a = [1, 2, 3, 4];
for ($i = 0;$i < $num;$i++) {
}
11. Control keywords such as if, for, foreach, while, switch, etc. should be followed by one blank space before the open parenthesis that follows them:
if ($my_var > 0) { } while ($still_working) {
}
switch ($selector) { } 12. Some leeway may be given on this if it helps make a line under 80 characters -- provided being under 80 characters helps program clarity. 13. Do not use unstable code layouts such as: $something1 = 25;
//...
$something10 = 25; //...$something100 = 27;
Although the equal signs are aligned, the spacing is unstable under changes of variable names. Do not have multiple statements on one line such as:
$a=1;$b=6; c=7; 14. Braces on class declarations, interface declarations, function declarations, and CSS declaration groups should be vertically aligned. For example, class MyClass { //code for class } interface MyInterface { //code for interface } function myFun() { //some code } .my-selector { //some css } 15. Braces for conditionals, loops, etc. should roughly follow the one true brace convention (1TBS): if (cond) { /*single statement should still use braces*/} if (cond) { //some statements } else if { // another condition } else { // yet another condition } switch (my_var) {
case 1:
break;
case 2:
//no break - should comment like this if don't have a break
case 3:
break;
default:
}
while (something) {
//do something
}
for ($i = 0;$i < $num;$i++) {
}
1. The body of conditionals, loops, etc. code blocks should be indented 4 spaces. Code should not appear on the same line as an opening brace or on the same line as a closing brace:
class MyClass
{ function MyFun //not allowed
{
}
}
if (something) {
$i++;$j++; } // not allowed
if (something) {
$i++;$j++;
} // good
An exception is allowed for single-line code blocks:
if (something) { $i++; } // is allowed if (something) {$i++;
} //is preferred
2. When a non-compound statement is split across several lines, all lines after the first should be indented four spaces:
//a long function call
setlocale(LC_ALL, $locale_tag,$locale_tag.'.UTF-8',
$locale_tag.'.UTF8',$locale_tag.".TCVN", $locale_tag.".VISCII",$locale_tag_parts[0], $locale_tag_parts[0].'.UTF-8',$locale_tag_parts[0].'.UTF8', $locale_tag_parts[0].".TCVN"); // a case where the conditional of an if is long if (!file_exists("$tag_prefix/statistics.txt") ||
filemtime("$tag_prefix/statistics.txt") < filemtime("$tag_prefix/configure.ini")) {
//code
}
Return to table of contents .
## PHP
Most of the code for Yioop is written in PHP. Here are some conventions that Yioop programmers should follow with regards to this language:
1. Yioop code should adhere to the PHP Framework Interop Group's PSR-2 Coding Style Guidelines.
2. Yioop code should all be in the seekquarry\yioop namespace or a subspace of this namespace. Global variables and other variables which affect namespace's outside seekquarry\yioop should not be used.
3. Code should be in classes other than web app entry points and the files: configs/Config.php, src/executables/CodeTool.php, src/library/LocaleFunctions.php, src/library/UpgradeFunctions.php, and src/library/Utility.php. Code should rely on the autoloading mechanism to load all other files.
4. The end of a PHP file should omit a final closing ?> and should have one blank line beyond the last text character line.
5. Classes should be organized as:
class MyClass
{
// Variable Declarations
var some_var;
// Constant Declarations
const SOME_CONTANTS;
// Constructor
function __construct()
{
// code
}
// abstract member functions, if any
/*
abstract function someAbstractMethod($arg1,$arg2)
{
// code
}
*/
//non static member functions
function someFunction($arg) { // code } // static member functions function someStaticFunction($arg)
{
// code
}
}
6. Except for loop variables where $i,$j, $k may be used, preference should be given to variable names which are full words.$queue rather than $q, for example. Some common abbreviations are permissible$dir (for directory), $db (for database),$str (for string), but should be avoided.
7. Variable names should be descriptive. If this entails multi-word variable names, then the words should be separated by underscores. For example, $crawl_order. 8. Defines, class constants, global variables (used in more than one file) should be written in all-caps. All other variables should be lowercase only. Some example defines in Yioop are: BASE_DIR, NAME_SERVER, USER_AGENT_SHORT. Some example global variables are:$INDEXED_FILE_TYPES, $IMAGE_TYPES,$PAGE_PROCESSORS. Some example class constants in Yioop are: CrawlConstants::GOT_ROBOT_TXT, CrawlConstants::INVERTED_INDEX, IndexDictionary::DICT_BLOCK_SIZE.
9. Function and member function names should be camel-cased beginning with a lowercase letter. For example, insert, crawlHash, getEntry, extractWordStringPageSummary.
10. Class and interface names should be camel-cased beginning with an uppercase letter. For example, CrawlConstants, IndexShard, WebArchiveBundle. Class names involved in the web-app portion of Yioop: controllers, elements, helpers, layouts, models, and views should begin with an uppercase letter, subsequent words except this last should be lowercase. For example, SearchfiltersModel, MachinestatusView. This facilitates Yioop's auto-loading mechanism.
11. Yioop code should not use language feature which would break backward compatibility with PHP 5.4.
12. Each require/include, define, global variable, function, class, interface, field, constant, member function should have a phpDoc docblock. These comments look like /** some comment */.
13. The GPL license should be included in a phpDoc (page-level) docblock which includes @author, @package, @subpackage, @license, @link http://www.seekquarry.com/, @copyright, and @filesource tags. See the example in the General guidelines section .
14. Field variables (PHP properties) docblock's should use @var to say the type of the field. For example,
/**
* Number of days between resets of the page url filter
* If nonpositive, then never reset filter
* @var int
*/
var $page_recrawl_frequency; 15. Multi-line phpDoc's should have a a vertical line of *'s. For example, /** * First line of a phpDoc is a short summary, should not rehash function name * * Then a blank comment line, followed by * a longer description. This in turn is followed by an @tags * * @param type$var_name description of variable
* @return type description of returned valued
*/
16. Each parameter of a function/member function should be documented with an @param tag. The return value of a function/member function should be documented with an @return tag. For example,
/**
* Subtracts the two values $value1 and$value2
*
* This function is intended to be used as a callback function for sorting
*
* @param float $value1 a value to take the difference between * @param float$value2 the other value
* @return float the difference
*/
function difference($value1,$value2)
{
return $value1 -$value2;
}
Notice the type of the argument/return value is give after the @tag. This could be NULL, int, float, string, array, object, resource, or mixed -- mixed, is used for return values which might return more than one type.
17. Multi-line comments within the body of a function or method should not use // such as:
// first line
// second line
C-style comments /* */ should be used instead.
18. Multi-line comments within the body of a function or method should not have a vertical stripe of stars. This prevents fragile layout problems with comments. For example, a good multi-line comment within a function might look like:
/*
This loop's end condition
will be satisfied by something clever.
*/
## Javascript
1. Variable names should not begin with $'s to avoid confusion with PHP. Except for this, they should follow the same conventions as PHP variable names described earlier. Here are some example Javascript variable names: i,j,k, request, message_tag. 2. Function names should be camel-cased beginning with a lowercase letter. For example, elt, redrawGroup, drawCrawlSelect. 3. Function docblock comments have the same format as PHP ones, but rather than use /** */ use /* */. For example, /* * Make an AJAX request for a url and put the results as inner HTML of a tag * * @param Object tag a DOM element to put the results of the AJAX request * @param String url web page to fetch using AJAX */ function getPage(tag, url) { //code } 4. Within functions, comments follow the same conventions as PHP. 5. One should avoid echoing Javascript within PHP code and instead move such code as much as possible to an external .js file. 6. Javascript should be included/inlined at the end of web pages not at the beginning. This allows browsers to begin rendering pages rather than blocking for pages to load. 7. Javascript output via PHP in a controller should be output in the$data['SCRIPT'] field sent in the $data variable to a view. 8. Localization needed by Javascript should be passed from PHP controllers using the$data['SCRIPT'] field sent in the $data variable to a view. For example, in PHP one might have: $data["MESSAGE"] = tl('admin_controller_configure_no_set_config');
$data['SCRIPT'] .= "doMessage('<h1 class=\"red\" >".$data["MESSAGE"] . "</h1>');" .
"setTimeout('window.location.href= ".
"window.location.href', 3000);";
The PHP function tl is used here to provide the translation, which will be used in the Javascript function call.
9. Javascript output by a PHP View should be output as much as possible outside of PHP tags <?php ... ?> rather than with echo or similar statements.
10. External Javascript files (.js files) should not contain any PHP code.
11. External Javascript files should be included using the $data['INCLUDE_SCRIPTS'] array. For example, $data['INCLUDE_SCRIPTS'] = ["script1", "script2"];
would include script1.js and script2.js from the Yioop script folder.
## CSS
1. CSS should W3C validate as either CSS 2 or CSS 3. CSS 3 styles should fail gracefully on non-supported browsers. Use of browser specific extensions such as -ms, -moz, -o, and -webkit selectors should only be for CSS 3 effects not yet supported by the given browser.
2. A CSS Rule Set in Yioop should follow one of the following formats:
/* single selector case */
selector
{
property1: value1; /* notice there should be a single space after the : */
property2: value2; /* all property-value pairs should be terminate with a
semi-colon */
...
}
/* multiple selector case */
selector1,
selector2,
...
{
property1: value1;
property2: value2;
...
}
3. Selectors should be written on one line. For example:
.html-rtl .user-nav ul li
Notice a single space is used between parts of this.
4. If an element should look different in a right-to-left language than a left-to-right language, then the .html-ltr and .html-rtl class selectors should be used. For example,
.html-ltr .user-nav
{
margin: 0 0.5in 0 0;
min-width: 10in;
padding: 0;
text-align: right;
}
.html-rtl .user-nav
{
margin: 0 0 0 0.5in;
min-width: 10in;
padding: 0;
text-align: left;
}
For vertically written languages, one can use the selectors: .html-rl-tb, .html-lr-tb, .html-tb-rl, .html-tb-lr. Finally, if an element needs to be formatted differently for mobile devices, the .mobile selector should be used:
.mobile .user-nav
{
font-size: 11pt;
min-width: 0;
left:0px;
padding: 0px;
position: absolute;
right: 0px;
top: -10px;
width: 320px;
}
5. To increase clarity, left-to-right, right-to-left, and mobile variants of the otherwise same selector should appear near each other in the given stylesheet file.
6. Class and ID selectors should be lowercase. Multi-word selector names should have the words separated by a hyphen:
.mobile
#message
#more-menu
.user-nav
7. Multiple selectors should be listed in alphabetical order. Properties in a rule-set should be listed alphabetically. For example,
.html-ltr .role-table,
.html-ltr .role-table td,
.html-ltr .role-table th
{
border: 1px solid black;
margin-left: 0.2in;
padding: 1px;
}
An exception to this is a browser-specific property should be grouped next to its CSS3 equivalent.
## HTML
1. Any web page output by Yioop should validate as HTML5. This can be checked at the site http://validator.w3.org/.
2. Any web page output by Yioop should pass the Web accessibility checks of the WAVE Tool.
3. Web pages should render reasonably similarly in any version of Chrome, Firefox, Internet Explorer, Opera, or Safari released since 2016. To test this, it generally suffices to test a 2016 version of each of these browsers together with a current version.
4. All tags in a document should be closed, but short forms of tags are allowed. i.e., a tag like <br> must have a corresponding close tag </br>; however, it is permissible to use the short open-close form <br />.
5. All tag attribute should have their values in single or double quotes:
<tag attribute1='value1' attribute2='value1' >
not
<tag attribute1=value1 attribute2=value1 >
6. For any given tag, name attribute values should be different than their id attribute values. For multi-word name attribute values, separate words with underscore, for id attributes, separate them with hyphens. For example,
<input id="some-form-field" name="some_form_field" type="text" />
7. HTML code is output in views, elements, helpers, and layouts in Yioop. This code might be seen in one of two contexts: Either by directly looking at the source code of Yioop (so one can see the PHP code, etc.) or in a browser or other client when one uses the client's "View Source" feature. Code should look reasonably visually appealing in either context, but with preference given to how it looks as source code. Client-side HTML is often a useful tool for debugging however, so should not be entirely neglected.
8. Generating code dynamically all on one line should be avoided. Client-side HTML should avoid lines longer than 80 characters as well.
9. Although not as strictly followed as for braces, an attempt should be made to align block-level elements. For such an element, one should often place the starting and ending tag on a line by itself and nest the contents by four spaces, if possible. This is not required if the indentation level would be too deep to easily read the line. Inline elements can be more free-form:
<ol>
<li>Although not as strictly followed as for braces, an attempt
should be made to align block-level elements. For such an element, one
should often place the starting and ending tag on a line by itself and nest
the contents by <b>four spaces</b>, if possible. This is not
required if the indentation level would be too deep to easily read the line.
Inline elements can be more free-form:
</li>
</ol>
Notice we indent for the ol tag. Since starting text on a separate line for an li tag might affect appearance, adding a space to the output, we don't do it. We do, however, put the close tag on a line by itself. In the above the b tag is inlined.
10. Here are some examples of splitting long lines in HTML:
<-- Long open tags -->
<-- case where content start and end spacing affects output -->
<tag attr1="value1" attr2="value2"
attr3="value3">contents</tag>
<-- or, if it doesn't affect output: -->
<tag attr1="value1" attr2="value2"
attr3="value3">
contents
</tag>
<-- Long urls should be split near '/', '?', '&'. Most browsers
ignore a carriage return (without spaces) at such places in a url
-->
<a href="http://www.cs.sjsu.edu/faculty/
pollett/masters/Semesters/Fall10/vijaya/index.shtml">Vijaya Pamidi's
master's pages</a>
11. Urls appearing in HTML should make use of the HTML entity for ampersand: & rather than just a & . Browsers will treat these the same and this can often help with validation issues.
## SQL
SQL in Yioop typically appears embedded in PHP code. This section briefly describes some minor issues with the formatting of SQL, and, in general, how Yioop code should interact with databases.
1. Except in subclasses of DatasourceManager, Yioop PHP code should not directly call native PHP database functions. That is, functions with names beginning with db2_, mysql_, mysqli_, pg_, orcl_, sqlite_, etc., or similar PHP classes. A DatasourceManager object exists as the $db field variable of any subclass of Model. 2. SQL should not appear in Yioop in any functions or classes other than subclasses of Model. 3. SQL code should be in uppercase. An example PHP string of SQL code might look like: $sql = "SELECT LOCALE_NAME, WRITING_MODE ".
" FROM LOCALE WHERE LOCALE_TAG = ?";
4. New tables names and field names created for Yioop should also be uppercase only.
5. Multi-word names should be separated by an underscore: LOCALE_NAME, WRITING_MODE, etc.
6. New tables added to the Yioop should maintain its BCNF normalization. Denormalization should be avoided.
7. Yioop's DatasourceManager class does have a facility for prepared statements. Using prepared statements should be preferred over escaping query parameters. Below is exampled of prepared statements in Yioop called from a model:
$sql = "INSERT INTO CRAWL_MIXES VALUES (?, ?, ?, ?)";$this->db->execute($sql, [$timestamp, $mix['NAME'],$mix['OWNER_ID'], $mix['PARENT']]); Notice how the values that are to be filled in for the ? are listed in order in the array. execute caches the last statement it has seen, so internally if you call$db->execute twice with the same statement it doesn't do the lower level prepare call to the database the second time. You can also use named parameters, as in the following example:
$sql = "UPDATE VISITOR SET DELAY=:delay, END_TIME=:end_time, FORGET_AGE=:forget_age, ACCESS_COUNT=:account_count WHERE ADDRESS=:ip_address AND PAGE_NAME=:page_name";$this->db->execute($sql, [ ":delay"=>$delay, ":end_time" => $end_time, ":forget_age" =>$forget_age,
":account_count" => $access_count, ":ip_address" =>$ip_address, ":page_name" => $page_name]); 8. In the rare case where a non-prepared statement is used, strings should be properly escaped usingDatasourceManager::escape_string. For example, $sql = "INSERT INTO LOCALE".
"(LOCALE_NAME, LOCALE_TAG, WRITING_MODE) VALUES".
"('".$this->db->escapeString($locale_name).
"', '".$this->db->escapeString($locale_tag) .
"', '".$this->db->escapeString($writing_mode)."')";
Return to table of contents .
## Localization
Details on how Yioop can be translated into different languages can be found in the Yioop Localization Documentation . As a coder what things should be localized are given in the general considerations section of this document. In this section, we describe a little about what constitutes a good translation, and then talk a little about, as a coder, how you should add new strings to be localized. We also make some remarks on how localization patches should be created before posting them to the issue tracker. This section describes how Yioop should be localized. The seekquarry.com site is also localizable. If you are interested in translating the Yioop documentation or pages on seekquarry.com, drop me a line at: [email protected] .
1. It can take quite a long time to translate all the strings in Yioop. Translations of only some of the missing strings for some locale are welcome! Preference should be given to strings that an end-user is likely to see. In order of priority one should translate string ids beginning with search_view_, pagination_helper_, search_controller_, signin_element_, settings_view_, settings_controller_, web_layout_, signin_view_, static_view_, statistics_view_.
2. For static pages, there are two versions -- those included with the Yioop download, and those on the the order of translation should be: privacy.thtml, bot.thtml, 404.thtml, and 409.thtml. For translations of the privacy statement for yioop.com, you should add a sentence saying the meaning of English statement takes precedence over any translations.
3. Localization should be done by a native (or close to) speaker of the language Yioop is being translated to. Automated translations using things like Google Translate should be avoided. If used, such translations should be verified by a native speaker before being used.
4. There are three main kinds of text which might need to be localized in Yioop: static strings, dynamic strings, and static pages.
5. Text that has the potential to be output by the Yioop web interface should only appear in views, elements, helpers, layouts, or controllers. Controllers should only pass the string to be translated to a view, which in turn outputs it; rather than directly output it.
6. If you need Javascript to output a translatable string, use a PHP controller to output a Javascript variable into $data['SCRIPT'], then have your Javascript make use of this variable to provide translation on the client. External .js files should not contain PHP code. An example of using this mechanism is given by the files mix.js and admin_controller.php's editMix member function. 7. String ids should be all lowercase, with an underscore used to separate words. They should follow the convention: file_name_approximate_english_translation. For example, signin_view_password is a string id which appears in the views/SigninView.php file, and in English is translated as Password. 8. Dynamic strings ids are string ids stored in the database and which may be added by administrators after downloading Yioop. String ids for these strings should all be in the format: db_use_case_translation. For example, db_activity_manage_locales or db_subsearch_images . 9. All suggested localizations posted to the issue tracker should be UTF-8 encoded. 10. If the only string ids you have translated are static ones, you can just make a new issue in the issue tracker and post the relevant configure.ini file. These files should be located in the Yioop Work Directory/locale/locale_in_question . Ideally, you should add strings through Manage Locales, which will modify this file for you. 11. For dynamic string translations just cut-and-paste the relevant line from Edit Locales into a new note for your issue. 12. Wiki pages for the Public and Help groups are also useful to have translated. Again, how to set up localizations of wiki pages is described in Yioop Localization Documentation . Once you have translated these pages on your local system, you can run the script configs/ExportPublicHelpDb.php to export this information to a file in APP_DIR/configs/PublicHelpPages.php which you can send. ## Code-base Organization This section describes what code should be put where when writing new code for Yioop. It can serve as a rough guide as to where to find stuff. Also, coding organization is used to ensure the security of the overall Yioop software. Some of the material in this section overlaps with what is described in the Summary of Files and Folders and the Building a Site using Yioop as a Framework sections of the main Yioop documentation. All folder paths listed in this section are with respect to the Yioop INSTALL_DIR/src folder, or, in the case of tests, just the INSTALL_DIR folder. 1. There are two main categories of apps in Yioop: the command line tools and programs, and the Yioop web app. 2. Core libraries common to both kinds of apps should be put in the library folder. One exception to this are subclasses of DatasourceManager. DatasourceManager has database and filesystem functions which might be useful to both kinds of apps. It is contained in models/datasources. The easiest way to create an instance of this class is with a line like: $model = new Model(); // $model->db will be a DatasourceManager 3. Some command-line programs such as executables/Fetcher.php and executables/QueueServer.php communicate with the web app either through curl requests or by file-based message passing. As a crude way to the check integrity of these messages as well as to reduce the size of serializations of the messages sent, the CrawlConstants interface defines a large number of shared class constants. This interface is then implemented by all classes that have need of this kind of message passing. CrawlConstants is defined in the file library/CrawlConstants.php . 4. Command-line tools useful for general Yioop configuration together with the Yioop configuration files Config.php and LocalConfig.php should be put in the configs folder. Some examples are: ConfigureTool.php and Createdb.php . 5. All non-configuration command-line tools should be in the executables folder. 6. Example scripts such as the file search.php which demonstrates the Yioop search API should be in the examples folder. 7. External Javascripts should be in the scripts folder, CSS should be the css folder, images should be in the resources folder, and sqlite3 databases in the data folder. 8. Code (PHP and Javascript) related to a particular locale should be in the folder locale/locale-tag/resources. Examples of this are the files: locale/en_US/resources/locale.js and locale/en_US/resources/Tokenizer.php . 9. Unit tests and coding experiments (the latter might test different aspects about speed and memory usage of PHP or Javascript constructs) should be in the tests folder. Auxiliary files to these tests and experiments should be put in tests/test_files. 10. Unit tests should be written for any new lib folder files. Unit tests should be a subclass of UnitTest which can be found in library/UnitTest.php. The file name for a unit test should end in Test.php to facilitates it detection by tests/index.php which is used to run the tests. As much as possible unit tests should be written for executables folder programs and the web app as well. 11. Command-line tools should have a check that they are not being run from the web such as: // if the command-line program does not have a unit test if(php_sapi_name() != 'cli') {echo "BAD REQUEST"; exit();} // if the command-line program has a unit test if (!defined("seekquarry\\yioop\\configs\\UNIT_TEST_MODE")) { if (php_sapi_name() != 'cli') {echo "BAD REQUEST"; exit();} } 12. Files other than command line programs, ./index.php, and ./tests/index.php should not define the UNIT_TEST_MODE constants. All code in non-command line programs should be in class, interface, or function definitions. I.e., they should have no globally executing statements. 13. The entry points into the web app should output the HTTP header: header("X-FRAME-OPTIONS: DENY"); to try to prevent clickjacking. 14. The only file to specify the autoloader for Yioop is configs/Config.php. It also defines important namespace level constants. It is require'd by both library/Utility.php and library/LocaleFunctions.php. Requiring any one of these files thus specifies the autoloader and important namespace constants. The base classes Controller, Model, View, etc., each require at least one of these files, so subclasses shouldn't. 15. The Yioop web app has the following kinds of files: controllers, models, views, (these three are main three); and components, element, helpers, and layouts (lesser). These should be put respectively into the folders: controllers, models, views, controllers/components, views/elements, views/helpers, views/layouts. Filenames should for these files should end with its type: i.e., a view should end with View.php, for example, MyView.php . 16. A view roughly corresponds to one web page, a layout is used to render common page headers and footers for several views, an element is used for a relatively static portion of a web page which might appear in more than one view, and a helper is used to dynamically render a web page element such as a select tag according to passed PHP variables. 17. Views, elements, and layouts should contain minimal PHP and be mostly HTML. In these classes for, while, etc. loops should be avoided. PHP in these classes should be restricted to simple conditionals and echos of$data variable fields.
18. Control logic involving conditionals, loops, etc. should be put in controllers or components. Components are collections of related methods which might be used by several controllers. The controller's static field $component_activities is used to define which components live on a controller and what activities from that component are allowed. A component has a$parent field that allows access to the controller it currently lives on.
19. In the web app, only models should access the file system or a database.
20. Variables whose values come from a web client should be cleaned before used by a view or a model. Subclasses of Controller have a clean() member function for this purpose. Further DatasourceManager's have an escapeString method which should be used on string before inserting them into a database in a Model.
21. Models, views, elements, helpers, and layouts should not use the $_GET,$_POST, $_REQUEST super-globals. Controllers should not use$_GET and $_POST, at most they should use$_REQUEST. This helps facilitates changing whether HTTP GET or POST is used -- also, using the same variable name for both a GET and POST variable is evil -- this restriction may (or may not) help in catching such errors.
22. For controllers which use the $_SESSION super-global, the integrity of the session against cross-site request forgery should be checked. This should be done in the processRequest method using code like: if(isset($_SESSION['USER_ID'])) {
$user =$_SESSION['USER_ID'];
} else {
$user =$_SERVER['REMOTE_ADDR'];
}
$data[CSRF_TOKEN] =$this->generateCSRFToken($user);$token_okay = $this->checkCSRFToken(CSRF_TOKEN,$user);
if(\$token_okay) {
//now can do stuff
}
23. When creating a new release of Yioop, one should check if any required database or locale changes were made since the last version. If database changes have been made, then configs/Createdb.php should be updated. Also library/UpgradeFunctions.php should have a new upgradeDatabaseVersion function added. If locale changes need to be pushed from BASE_DIR/locale files to WORK_DIRECTORY/locale files when people upgrade, then one should change increase the RESOURCES_WIKI_VERSION constant in src/configs/Config.php. A number of variables control whether client-side, HTML5 localStorage related to the previous release will still work with the new release. If it won't work, then this version number should be updated. An example of such a variable is SUGGEST_VERSION_NO in suggest.js.
## Issue Tracking/Making Patches/Commit Messages
In this section we discuss the Yioop issue tracker and discuss using the git version control system to make and apply patches for Yioop.
1. If you would like to contribute code to Yioop, but don't yet have an account on the issue tracker, you can sign up for an account.
2. After one has an account and is logged in, one can click the Report Issue link to report an issue. Be sure to fill in as many report fields and give as much detail as possible. In particular, you should select a Product Version.
3. The Upload File fieldset lets you upload files to an issue and the Add Note fieldset allows you to add new notes. This is where you could upload a patch. By default, a new account is a Reporter level account. This won't let you set people to moniter (get email about) the issue besides yourself. However, the administrator will be aware the issue was created.
4. A developer level account will allow you to change the status of issues, update/delete issues, set who is monitoring an issue, and assign issues to individuals. This can be done through the fieldset just beneath Attached Files.
5. Information about Git, Git clients, etc. can be obtained from: http://git-scm.com/. Here we talk about a typically workflow for coding Yioop using Git.
6. After installing git, make sure to configure your user name and email address:
% git config --global user.name "Chris Pollett"
% git config --global user.email "[email protected]"
You should of course change the values above to your name and email. To see your current configuration settings you can type:
% git config -l
If you want to remove any settings you can type:
% git config --unset some.setting.you.dont.want
Setting the user name and email will ensure that you receive credit/blame for any changes that end up in the main git repository. To see who is responsible for what lines in a file one can use the git blame command. For example:
% git blame yioopbar.xml
|chris-polletts-macbook-pro:yioop:526>git blame yioopbar.xml
git blame yioopbar.xml
ad3c397c (Chris Pollett 2010-12-28 00:27:38 -0800 1) <?xml version="1.0" e
ad3c397c (Chris Pollett 2010-12-28 00:27:38 -0800 2) <OpenSearchDescriptio
ad3c397c (Chris Pollett 2010-12-28 00:27:38 -0800 3) <ShortName>Yioop<
ad3c397c (Chris Pollett 2010-12-28 00:27:38 -0800 4) <Description>Quickly
ad3c397c (Chris Pollett 2010-12-28 00:27:38 -0800 5) <InputEncoding>UTF-8
ad3c397c (Chris Pollett 2010-12-28 00:27:38 -0800 6) <Image width="16" hei
774eb50d (Chris Pollett 2012-12-31 10:47:57 -0800 7) <Url type="text/html"
774eb50d (Chris Pollett 2012-12-31 10:47:57 -0800 8) template="http://
ad3c397c (Chris Pollett 2010-12-28 00:27:38 -0800 9) </Url>
774eb50d (Chris Pollett 2012-12-31 10:47:57 -0800 10) </OpenSearchDescripti
7. To make a new copy of the most recent version of Yioop one can run the git clone command:
% git clone https://seekquarry.com/git/yioop.git yioop
This would create a copy of the Yioop repository into a folder yioop in the current directory. Thereafter, to bring this copy up to date with the most recent version of yioop one can issue the command:
% git pull
8. Once one has a git clone of Yioop -- or done a git pull of the most recent changes to Yioop -- one can start coding! After coding a while you should run git status to see what files you have changed. For example,
% git status
# On branch master
# Your branch is behind 'origin/master' by 1 commit, and can be fast-forwarded.
#
# Untracked files:
# (use "git add <file>..." to include in what will be committed)
#
# tmp.php
nothing added to commit but untracked files present (use "git add" to track)
This says there has been one commit to the main repository since your clone / last git pull. It also says we could bring things up to date by just doing a git pull. In this case, however, it says that there was an untracked file in the repository. If this file was a file we made with the intention of adding it to Yioop, we should type git add to add it. For example,
% git add tmp.php
Now we could try to do a git pull. Suppose we get the message...
Updating e3e4f20..a9a8ed9
error: Your local changes to the following files would be overwritten by merge:
tmp.php
Please, commit your changes or stash them before you can merge.
Aborting
What this means is that someone else has also added tmp.php and there are conflicts between these two versions. To merge these two versions, we first commit our version:
% git commit -a -m "Fixes Issue 987, Yioop needs a tmp.php file, a=chris"
[master 3afe055] Fixes Issue 987, Yioop needs a tmp.php file, a=chris
1 file changed, 4 insertions(+)
create mode 100644 tmp.php
The option -a tells git to put in the commit all changes done to staged files (those that we have git add'd) since the last commit. The option -m is used to give an inline message. The general format of a of such a message in Yioop is: which issue number in the issue tracker is being fixed, a brief English summary of that issue, and under whose authority the commit is being done. This last will be in the format a=chris where a means approved and the person who approved is of sufficient seniority to commit unreviewed things or in the format r=someone, where someone is the person asked in the issue to review your commits before they are pushed. Often for administrator commits, there won't be an associated issue tracking issue, in which case the format reduces to: some useful English description of the change, a=username of administrator. Now that we have done the above commit, we can try again to do a git pull:
% git pull
Auto-merging tmp.php
CONFLICT (add/add): Merge conflict in tmp.php
Automatic merge failed; fix conflicts and then commit the result.
%cat tmp.php
cat tmp.php
<?php
<<<<<<< HEAD
echo "hello";
echo "good bye";
=======
>>>>>>> a9a8ed990108598d06334e29c0eb37d98f0845aa
?>
The listing of the tmp.php file above has blocks of the form: <<<<<<< HEAD, =======, >>>>>>> a9a8ed990108598d06334e29c0eb37d98f0845aa. In this case, there is only one such block, in general, there could be many. The stuff before the ======= in the block is in the local repository, the stuff after the ======= is in the remote repository. So in the local copy, there are the two lines:
echo "hello";
echo "good bye";
not in the remote repository. On the other hand, there is nothing in the remote repository not in the local copy. So we could fix this conflict by editing this block to look like:
<?php
echo "hello";
echo "good bye";
?>
In general, we should fix each conflict block if there is more than one. Conflicts can also be in more than one file, so we could have to fix each file with conflicts. Once this is done, to tell git we have resolved the conflict, we can type:
% git add tmp.php
% git commit
[master e5ebf9f] Merge branch 'master' of https://seekquarry.com/git/yioop
Here we didn't use -m, so we were dropped into the vi text editor, where we left the default commit message. Now we can go back to editing our local copy of Yioop. If we do a git pull at this point, we will get the message: "Already up-to-date."
9. The "opposite command" to git pull is git push. Most casual developers for Yioop don't have push privileges on the main Yioop repository. If one did, a possible development workflow would be: Pull the master copy of Yioop to a local branch, make your changes and post a patch to the Bug/Issue in question on the issue tracker asking someone to review it (probably, the administrator, which is me, Chris Pollett). The reviewer gives a thumbs up or down. If it is a thumbs up, you push your changes back to the master branch. Otherwise, you revise you patch and try again. To configure git so git push works you can either make a ~/.netrc file with
machine seekquarry.com
login <username>
password <password>
in it, chmod it to 600, and type:
% git config remote.upload.url https://seekquarry.com/git/yioop.git
or you can just type the command:
% git config remote.upload.url \
https://<username>@seekquarry.com/git/yioop.git
After this, you should be able to use the command:
% git push upload master
This pushes your local changes back to the repository. In the second method, you will be prompted for your password. Another common setting that you might to change is http.sslVerify. If you are getting error messages such as
error: server certificate verification failed. CAfile:
/etc/ssl/certs/ca-certificates.crt CRLfile: none
while accessing https://seekquarry.com/git/yioop.git/info/refs
you might want to use the command:
% git config --global --add http.sslVerify false
10. In the workflow above, the changes we make to our local repository should be reviewed before we do a push back to the Yioop repository. To do this review, we need to make a patch, upload the patch to the issue tracker, and add someone to this issue monitor list who could review it, asking them to do a review. These last two steps require the user to have at least a developer account on the issue tracker. Anyone who registers for the issue tracker gets initially a reporter account. If you would like to code for Yioop and have already made a patch, you can send an email to [email protected] to request your account to be upgraded to a developer account. New developers do not get push access on the Yioop repository. For such a developer, the workflow is create a patch, post it to an issue on the issue tracker, get it approved by an administrator reviewer, then the reviewer pushes the result to the main Yioop repository.
11. After coding, but before making a patch you should run executables/CodeTool.php to remove any stray tab characters, or spaces at the end of lines. This program can be run either on a single file or on a folder. For example, one could type:
% php executables/CodeTool.php clean tmp.php
This assumes you were in the Yioop base directory and that was also the location of tmp.php. You should also run the command:
% php executables/CodeTool.php longlines tmp.php
to check for lines over 80 characters.
12. To make a patch, we start with an up-to-date copy of Yioop obtained by either doing a fresh clone or by doing a git pull. Suppose we create a couple new files, add them to our local repository, do a commit, delete one of these files, make a few more changes, and commit the result. This might look on a Mac or Linux system like:
% ed test1.php
test1.php: No such file or directory
a
<?php
?>
.
wq
9
% ed test2.php
test2.php: No such file or directory
a
<?php
?>
.
wq
9
% git add test1.php
% git add test2.php
% git commit -a -m "Adding test1.php and test2.php to the repository"
[master 100f787] Adding test1.php and test2.php to the repository
2 files changed, 4 insertions(+)
create mode 100644 test1.php
create mode 100644 test2.php
% ed test1.php
9
1
<?php
a
phpinfo();
.
wq
24
% git rm test2.php
rm 'test2.php'
% ls
./ README* data/ locale/ search_filters/
../ bin/ error.php* models/ test1.php
.DS_Store* blog.php* examples/ my.patch tests/
.git/ bot.php* extensions/ privacy.php* views/
.gitignore configs/ favicon.ico resources/ yioopbar.xml
INSTALL* controllers/ index.php* robots.txt
LICENSE* css/ lib/ scripts/
% git commit -a -m "Adding phpinfo to test1.php, removing test2.php"
[master 7e64648] Adding phpinfo to test1.php, removing test2.php
2 files changed, 1 insertion(+), 2 deletions(-)
delete mode 100644 test2.php
Presumably, you will use a less ancient editor than ed. ed though does have the virtue of not clearing the screen, making it easy to cut and paste what we did. We now want to make a patch consisting of all the commits since we did the git pull. First, we get the name of the commit before we started modifying stuff by doing git log -3 to list out the information about the last three commits. If you had done more commits or less commits since the git pull then -3 would be different. We see the name is e3e4f20674cf19cf5840f431066de0bccd1b226c. The first eight or so characters of this uniquely identify this commit, so we copy them. To make a patch with git, one uses the format-patch command. By default this will make a separate patch file for each commit after the starting commit we choose. To instead make one patch file we use the --stdout option and redirect the stream to my.patch. We can use the cat command to list out the contents of the file my.patch. This sequence of commands looks like the following...
% git log -3
commit 7e646486faa35f69d7322a8e4fca12fb6b457b8f
Author: Chris Pollett <[email protected]>
Date: Tue Jan 1 17:32:00 2013 -0800
Adding phpinfo to test1.php, removing test2.php
commit 100f7870221d453720c90dcce3cef76c0d475cc8
Author: Chris Pollett <[email protected]>
Date: Tue Jan 1 16:35:02 2013 -0800
Adding test1.php and test2.php to the repository
commit e3e4f20674cf19cf5840f431066de0bccd1b226c
Author: Chris Pollett <[email protected]>
Date: Tue Jan 1 15:48:34 2013 -0800
modify string id in settings_view, remove _REQUEST variable from
machinelog_element, a=chris
% git format-patch e3e4f2067 --stdout > my.patch
% cat my.patch
From 100f7870221d453720c90dcce3cef76c0d475cc8 Mon Sep 17 00:00:00 2001
From: Chris Pollett <[email protected]>
Date: Tue, 1 Jan 2013 16:35:02 -0800
Subject: [PATCH 1/2] Adding test1.php and test2.php to the repository
---
test1.php | 2 ++
test2.php | 2 ++
2 files changed, 4 insertions(+)
create mode 100644 test1.php
create mode 100644 test2.php
diff --git a/test1.php b/test1.php
new file mode 100644
index 0000000..acb6c35
--- /dev/null
+++ b/test1.php
@@ -0,0 +1,2 @@
+<?php
+?>
diff --git a/test2.php b/test2.php
new file mode 100644
index 0000000..acb6c35
--- /dev/null
+++ b/test2.php
@@ -0,0 +1,2 @@
+<?php
+?>
--
1.7.10.2 (Apple Git-33)
From 7e646486faa35f69d7322a8e4fca12fb6b457b8f Mon Sep 17 00:00:00 2001
From: Chris Pollett <[email protected]>
Date: Tue, 1 Jan 2013 17:32:00 -0800
Subject: [PATCH 2/2] Adding phpinfo to test1.php, removing test2.php
---
test1.php | 1 +
test2.php | 2 --
2 files changed, 1 insertion(+), 2 deletions(-)
delete mode 100644 test2.php
diff --git a/test1.php b/test1.php
index acb6c35..e2b4c37 100644
--- a/test1.php
+++ b/test1.php
@@ -1,2 +1,3 @@
<?php
+ phpinfo();
?>
diff --git a/test2.php b/test2.php
deleted file mode 100644
index acb6c35..0000000
--- a/test2.php
+++ /dev/null
@@ -1,2 +0,0 @@
-<?php
-?>
--
1.7.10.2 (Apple Git-33)
13. One should always list out the patch as we did above before posting it to the issue tracker. It can happen that we accidentally find that we have more things in the patch than we should. Also, it is useful to do one last check that the Yioop coding guidelines seem to be followed within the patch.
14. The last step before uploading the patch to the issue tracker is to just check that the patch in fact works. To do this make a fresh clone of Yioop. Copy my.patch into your clone folder. To see what files the patch affects, we can type:
% git apply --stat my.patch
test1.php | 2 ++
test2.php | 2 ++
test1.php | 1 +
test2.php | 2 --
4 files changed, 5 insertions(+), 2 deletions(-)
Since there are two concatenated patches in my.patch, it first lists the two files affected by the first patch, then the two files affected by the second patch. To do a check to see if the patch will cause any problems before applying it, one can type:
% git apply --check my.patch
Finally, to apply the patch we can type:
% git am --signoff < my.patch
Applying: Adding test1.php and test2.php to the repository
Applying: Adding phpinfo to test1.php, removing test2.php
</pre>
The am says apply from a mail, the --signoff option says to write a
commit message with your email saying you approved this commit. From
the above we see each patch within my.patch was applied in turn. To
see what this signoff looks like, we can do:
<pre>
commit aca40730c41fafe9a21d4f0d765d3695f20cc5aa
Author: Chris Pollett <[email protected]>
Date: Tue Jan 1 17:32:00 2013 -0800
Adding phpinfo to test1.php, removing test2.php
Signed-off-by: Chris Pollett <[email protected]>
commit d0d13d9cf3059450ee6b1b4a51db0d0fae18256c
Author: Chris Pollett <[email protected]>
Date: Tue Jan 1 16:35:02 2013 -0800
Adding test1.php and test2.php to the repository
Signed-off-by: Chris Pollett <[email protected]>
commit e3e4f20674cf19cf5840f431066de0bccd1b226c
Author: Chris Pollett <[email protected]>
Date: Tue Jan 1 15:48:34 2013 -0800
modify string id in settings_view, remove _REQUEST variable from
machinelog_element, a=chris
At this point the patch seems good to go, so we can upload it to the issue tracker!
## New Version Quality Assurance Checklist
The following should be check before creating a new release of Yioop:
1. All unit tests pass.
2. Included sqlite databases public_default.db, private_default.db are up-to-date.
3. Install guides are up to date and installation can be performed as described for each of the major platforms (Linux variants, Macos, Windows, HHVM).
4. Upgrade functions successfully upgrade Yioop from last version. Upgrade functions need only be written from the last official release to the current official release.
5. Yioop can perform a regular and archive crawl on each of the platforms for which an install guide has been made.
6. Each kind of archive iterator has been tested on the development platform to be still working.
7. Multi-queue server crawls should be tested. Mirror and Media updater processes should be tested.
8. Documentation reflects changes since last version of Yioop, screenshots have been updated.
9. Source code documentation has been updated. The current command used to do this is
php phpDocumentor.phar -d ./yioop -t ./yioop_docs --ignore="yioop/work_directory" --ignore="yioop/vendor" \
--sourcecode --title="Yioop_Vversion_Source_Code_Documentation"
The line above was last used with the release candidate of phpdoc 3. This line should be executed from one directory up from the Yioop source code. To facilitate this it is handy to have a shell script, say php_doc.sh, with this command in it with a full path to a older version of PP
10. Each admin panel activity and each setting within each activity works as described.
11. Web app still appears correctly for major browsers: Chrome, Edge, Firefox, Internet Explorer, Safari released in the last two years.
|
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http://the-paper-trail.org/blog/consensus-protocols-a-paxos-implementation/
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### Consensus Protocols: A Paxos Implementation
It’s one thing to wax lyrical about an algorithm or protocol having simply read the paper it appeared in. It’s another to have actually taken the time to build an implementation. There are many slips twixt hand and mouth, and the little details that you’ve abstracted away at the point of reading come back to bite you hard at the point of writing.
I’m a big fan of building things to understand them – this blog is essentially an expression of that idea, as the act of constructing an explanation of something helps me understand it better. Still, I felt that in order to be properly useful, this blog probably needed more code.
So when, yesterday, it was suggested I back up my previous post on Paxos with a toy implementation I had plenty of motivation to pick up the gauntlet. However, I’m super-pressed for time at the moment while I write my PhD thesis, so I gave myself a deadline of a few hours, just to keep it interesting.
A few hours later, I’d written this from-scratch implementation of Paxos. There’s enough interesting stuff in it, I think, to warrant this post on how it works. Hopefully some of you will find it useful, and something you can use as a springboard to your own implementations. You can run an example by simply invoking python toy_paxos.py.
I’m not going to go over again how Paxos works – in fact I’m going to assume that you’ve read and understood my previous post on the subject. However, there’s an extra couple of bits of detail that you’ll need to understand some of the things in the code.
It might help to clarify the abstraction this code is trying to present. I’m using Paxos to simulate a state machine, where the leader proposes a value for the next command for the acceptors to agree upon. Therefore, rather than run just one instance of Paxos, we’re running many consecutive instances, the $n^{th}$ of which is concerned with agreeing on the $n^{th}$ command in sequence. In the code, this index is identified as the instanceID. So now every proposal carries with it a value, a proposal ID and an instance ID.
The idea is to agree upon an ordered history of state machine commands, one command per instance. Clients propose a value for a command they’d like to execute. The consensus service orders these commands and notifies any interested parties. Occasionally, it might happen that there are holes in the history that a leader knows about. In that case, the leader can simply propose a ‘no-op’ value (here 0), and will learn about the real value if there is one, as Paxos ensures that a previously accepted value will stay accepted. Otherwise, 0 gets inserted in the history with no ill-effect.
The code is structured into four main classes. Two are ‘actor’ classes, PaxosLeader and PaxosAcceptor. These two classes receive messages from each other and the outside world (in the leader’s case), kick off protocol instances, get notified when protocols have finished and so on. The other two important classes are PaxosLeaderProtocol and PaxosAcceptorProtocol. These are state-machine classes that keep track of one actor’s view of the state of a single protocol instance. The important code for these two is mainly in doTransition, which takes a message object, looks at the current protocol state, and figures out what to do with it.
Of the two actor classes, PaxosAcceptor is much the simpler. Both classes are attached to a MessagePump class, which listens on a socket and copies messages to a queue for the actor class to consume one by one.
(Note the convoluted thread-within-thread copying from the socket onto a synchronised queue inside the MessagePump – the problem is that I was filling the UDP receive buffer quicker than the actor could pull messages from the socket, so I needed to empty the buffer as soon as possible, asynchronously. I don’t actually know if TCP would have helped here – does the acknowledgement of a packet get sent when the socket is read?)
MessagePump calls back into recvMessage, which in the PaxosAcceptor case simply checks if the message contains a new proposal. If it does, a new PaxosAcceptorProtocol object is created and set loose. Otherwise, the corresponding protocol is looked up through the InstanceRecord structure (of which there is one per instance, and simply contains a table of all known proposals for that instance), and doTransition is called through.
For PaxosLeader, recvMessage is a bit more complicated. The first chunk of code:
```if message == None: # Only run every 15s otherwise you run # the risk of cutting good protocols off in their prime if self.isPrimary and time.time( ) - self.lasttime > 15.0: # if no message is received, we take # the chance to do a little cleanup for i in xrange(1,self.highestInstance): if self.getInstanceValue( i ) == None: print "Filling in gap", i self.newProposal( 0, i ) self.lasttime = time.time( )```
only gets run if there is no message to process (and only then if it’s been more than 15s since we last ran this code). The idea is to run through all the instances we know about, and check if we’ve got a value for them. If we haven’t then we propose 0 as a no-op value, as above.
Otherwise, we look at the type of message we’ve received. Heartbeat messages come from other leaders, and are used to indicate that a leader thinks it is the current primary. If a leader thinks it is the primary and receives a heartbeat from a leader whose port number is higher, it yields to that leader. However, if no heartbeats have been heard for a period of time, any leader can assert itself as the primary, and start issuing heartbeats.
If the message comes from a client, the leader constructs a new protocol object and passes control to it, after saving it in the InstanceRecord for the current instance. This is done in newProposal. The current instance number is defaulted to one larger than the previous proposal. However, if we are filling in gaps then we may want to force the instance to an earlier value.
If the message belongs to a protocol we know about, we call through the doTransition as before. However, leaders also want to know about accepted proposals so that, if they need to take over, they can be reasonably up-to-date. Therefore every leader, whether or not it is the primary, runs the leader protocol for any proposals that have got to the accept phase – that is, they listen for a quorate number of accepts and then are aware when a proposal has been accepted and at what value.
Some other niceties: you can substitute AdversarialMessagePump in to arbitrarily delay messages and simulate asynchrony. Acceptors can simulate failure by calling fail( ) on them – they then stop responding to messages. In a proper implementation, you’d want to log to persistent storage every state change in both leader and acceptor so that if they were to genuinely crash and fail they could recover even having lost their memory.
This toy implementation has been designed to run on a single machine in one Python process. Therefore every message pump binds to localhost on a unique port (it would not be hard at all to generalise this to use proper IP addresses). There are doubtless a few bugs, and more than a few bits of ugliness. Let me know what you find!
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https://encyclopediaofmath.org/wiki/Hyperbolic_partial_differential_equation,_numerical_methods
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Hyperbolic partial differential equation, numerical methods
Methods for solving hyperbolic partial differential equations using numerical algorithms.
Various mathematical models frequently lead to hyperbolic partial differential equations. Only very infrequently such equations can be exactly solved by analytic methods. The most widely used methods are numerical methods. They find extensive use in solving problems of the mechanics of a continuous medium, in particular for the equations of gas dynamics (cf. Gas dynamics, numerical methods of), which are quasi-linear.
Numerical methods for solving hyperbolic partial differential equations may be subdivided into two groups: 1) methods involving an explicit separation of the singularities of the solution; 2) indirect computation methods, in which the singularities are not directly separated but are obtained in the course of the computation procedure as domains with sharp changes in the solutions.
The first group includes, for instance, the method of characteristics, which is only used for solving hyperbolic partial differential equations; it has found extensive use in solving the problems of gas dynamics.
The methods in the second group yield non-singular difference schemes (cf. Difference scheme). Let there be given, for example, the hyperbolic equation
$$\tag{1 } \frac{\partial w }{\partial t } = A \frac{\partial w }{\partial x } ,$$
where $A$ is an $( m \times m )$- matrix with $m$ distinct real eigen values and $w = w( x, t)$ is a vector function with $m$ components. The matrix $A$ may either be a function in $x$, $t$( in such a case (1) is a linear hyperbolic system), or may depend on $w = w ( x, t )$( a quasi-linear system). In the latter case, let the system of equations (1) be reduced to divergence form:
$$\frac{\partial w }{\partial t } = \ \frac{\partial F }{\partial x } + \psi ,$$
where $F$ is a vector function in $w$, $x$, $t$ such that $A = dF/dw$ and $\psi$ is a vector function in $w$, $x$, $t$. In the most important case $A$, $F$ and $\psi$ depend only on $w$. For (1) one may pose the Cauchy problem
$$w ( x, 0) = w _ {0} ( x)$$
with suitable boundary conditions.
As a rule, the basis on which finite-difference schemes are constructed is an approximation by the integral conservation law corresponding to the differential equation, using certain quadrature formulas on the contour of integration of the differential cell. If the solutions are smooth, approximation by the integral conservation law is equivalent to direct approximation of the corresponding differential equation. Finite-difference schemes must satisfy the approximation and stability requirements. These requirements are mutually independent and, in a sense, contradict one another. In divergence systems of differential equations it is the divergence (or the conservation) condition of the finite-difference scheme which is fundamental. Moreover, the finite-difference schemes must also satisfy a number of other necessary conditions, like dissipativeness, economy, etc. A two-level explicit finite-difference scheme for a linear equation of type (1) has the form
$$w _ {j} ^ {n + 1 } = \Lambda w _ {j} ^ {n} ,$$
where $\Lambda$ is a finite operator, i.e. can be represented in the form
$$\Lambda = \sum _ { \alpha = - q _ {1} } ^ { {q _ 2 } } B _ \alpha T _ {1} ^ \alpha ,$$
where $B _ \alpha$ are $( m \times m)$- matrices with coefficients that depend on $\tau$, $h$, $x$, $t$; $t = n \tau$, $x = jh$; $\tau$, $h$ are the steps of the finite-difference grid along the axis $t$ and $x$, respectively; the numbers $q _ {1}$ and $q _ {2}$ do not depend on $\tau$, $h$; $\kappa = \tau / h$; and $T _ {1}$ is a displacement operator with respect to $x$.
The consistency conditions lead to the relationships
$$\sum _ { \alpha = - q _ {1} } ^ { {q _ 2 } } B _ \alpha = I,$$
$$\sum _ { \alpha = - q _ {1} } ^ { {q _ 2 } } \alpha B _ \alpha = \kappa A,$$
where $I$ is the identity matrix.
The implicit finite-difference scheme may be written as follows:
$$\Lambda _ {1} w _ {j} ^ {n + 1 } = \Lambda _ {0} w _ {j} ^ {n} ,$$
where $\Lambda _ {1}$ and $\Lambda _ {0}$ are finite operators,
$$\Lambda _ {k} = \ \sum _ { \alpha = - q _ {1} } ^ { {q _ 2 } } B _ \alpha ^ {k} T _ {1} ^ \alpha ,\ \ k = 0, 1,$$
where $B _ \alpha ^ {k}$ are $( m \times m )$- matrices which depend on $\tau$, $h$, $x$, $t$, and the operator $\Lambda _ {1}$ contains at least two non-zero matrices $B _ \alpha ^ {1}$. The operator $\Lambda _ {1}$ is assumed to be invertible, but its inverse need not be finite.
The various schemes may be subdivided into two classes by their approximation properties: the conditionally approximating schemes and the absolutely-approximating schemes. The conditionally-approximating finite-difference schemes approximate the initial differential equation for $\tau$, $h$ tending to zero with a certain interdependence between them: $\tau = \phi ( h)$. Absolutely-approximating finite-difference schemes approximate the initial differential equation as $\tau$, $h$ tend to zero in accordance with an arbitrary law.
In the case of conditional approximation the finite-difference equation may approximate various differential equations for various conditions of limit transition. For instance, for the equation
$$\tag{2 } \frac{\partial u }{\partial t } + a \frac{\partial u }{\partial x } = 0,\ \ a = \textrm{ const } > 0,$$
one may consider, e.g., the two finite-difference schemes
$$\tag{3 } \left . \begin{array}{c} { \frac{u _ {j} ^ {n + 1 } - \overline{u}\; {} _ {j} ^ {n} } \tau } + a { \frac{u _ {j + 1 } ^ {n} - u _ {j - 1 } ^ {n} }{2h} } = 0, \\ \overline{u}\; {} _ {j} ^ {n} = { \frac{1}{2} } ( u _ {j + 1 } ^ {n} + u _ {j - 1 } ^ {n} ), \\ \end{array} \right \}$$
$$\tag{4 } { \frac{u _ {j} ^ {n + 1 } - u _ {j} ^ {n} } \tau } + a { \frac{u _ {j} ^ {n} - u _ {j - 1 } ^ {n} }{h} } = 0.$$
If the law governing the limit transition is
$${ \frac \tau {h} } = \textrm{ const } ,$$
then the finite-difference scheme (3) approximates equation (2), while if that law is
$${ \frac \tau {h} ^ {2} } = \textrm{ const } ,$$
it approximates the equation
$$\frac{\partial u }{\partial t } + a \frac{\partial u }{\partial x } = \mu \frac{\partial ^ {2} u }{\partial x ^ {2} } ,\ \ \mu = \frac{h ^ {2} }{2 \tau } .$$
The finite-difference scheme (4) absolutely approximates equation (2).
In a similar manner, finite-difference schemes may be subdivided into conditionally-stable schemes and absolutely-stable schemes. Thus, the finite-difference scheme (4) will be stable if the following condition (Courant's condition) is met:
$$\frac{\tau a }{h } \leq 1,$$
i.e. if it is conditionally stable. On the other hand, the implicit finite-difference scheme
$$\frac{u _ {j} ^ {n + 1 } - u _ {j} ^ {n} } \tau + a \frac{u _ {j + 1 } ^ {n + 1 } - u _ {j - 1 } ^ {n + 1 } }{2h } = 0$$
is stable for all relations between $\tau$ and $h$, i.e. it is absolutely stable.
Explicit finite-difference schemes are simple in realization, but are either conditionally stable or conditionally approximating. In the case of an absolutely-approximating finite-difference scheme the condition of stability of the explicit scheme usually has the form
$$\tau \leq \textrm{ const } \cdot h ^ \beta \ \ ( \beta \geq 1),$$
which results in too small a step $\tau$ and involves unjustifiable labour in computations. All absolutely-stable absolutely-approximating schemes are contained in the class of implicit schemes.
Implicit finite-difference schemes are more complex in realization on passing from one time level to another, but then the step size $\tau$ may often be chosen arbitrary large, and is thus determined by considerations of accuracy only.
The convergence theorems for finite-difference schemes approximating linear differential equations make it possible to reduce the study of the convergence of such schemes to a study of their stability.
The study of the approximation of a finite-difference scheme corresponding to a hyperbolic equation is rather simple in the case of smooth solutions, has a local character, and in fact amounts to expansion into Taylor series; if the solution is discontinuous, the problem becomes difficult and consists of the verification of integral conservation laws. The study of stability is much more complicated.
The stability of finite-difference schemes which approximate hyperbolic equations with constant coefficients is studied by the Fourier method — i.e. an estimate is made of the norm of the Fourier transform of the step operator of the finite-difference scheme. Since the spectral radius of the matrix of the Fourier transform of the step operator does not exceed the norm of the matrix, a necessary criterion for stability follows: For a finite-difference scheme to be stable it is necessary that the spectral radius of the Fourier transform of the step operator does not to exceed $1 + O ( \tau )$, where $\tau$ is the step of the scheme along the $t$- axis. This is also a necessary condition for finite-difference schemes with variable coefficients and, if certain supplementary restrictions are imposed, this is also a sufficient condition. The following methods are used in the study of finite-difference schemes with variable coefficients, as well as for certain non-linear equations: the method of majorizing or of a priori estimates, and a local algebraic method.
The method of a priori estimates is analogous to the corresponding method for differential equations, but in the case of finite differences its realization involves major difficulties, owing to the specific features of finite-difference analysis in which — unlike in the method of a priori estimates in the theory of differential equations — many relationships take a tedious form.
The simplest majorizing estimate is the estimate for finite-difference schemes with positive coefficients.
For instance, consider the following finite-difference scheme for equation (2) with $a = a( x)$:
$$\tag{5 } { \frac{u _ {j} ^ {n + 1 } - u _ {j} ^ {n} } \tau } + a _ {j} { \frac{u _ {j} ^ {n} - u _ {j - 1 } ^ {n} }{h} } = 0,\ \ a _ {j} = a ( jh).$$
Then, if
$$0 \leq 1 - \kappa _ {j} \leq 1,\ \ \kappa _ {j} = { \frac{\tau a _ {j} }{h} } ,$$
the following estimate holds:
$$\| u ^ {n + 1 } \| \leq \| u ^ {n} \| ,$$
where
$$\| u ^ {n} \| = \max _ { j } | u _ {j} ^ {n} | .$$
It follows that the scheme (5) is uniformly stable in the space $C$. This estimate can be applied to finite-difference schemes which approximate hyperbolic systems of equations in invariants.
A very important, though limited, class of finite-difference schemes is represented by schemes with positive coefficients and matrices (so-called majorant schemes). If the coefficients of such schemes are symmetric, positive and Lipschitz continuous with respect to $x$, then they are stable in the space $L _ {2}$. As a rule, these are finite-difference schemes of first-order approximation in which the derivatives are approximated by one-sided differences. In higher-order approximations, when central differences are taken, one need not obtain positive coefficients. In such cases a priori estimates of a more general type in the spaces $W _ {2} ^ {p}$ are used.
For instance, let (1) be an acoustic scheme where
$$w = \left ( \begin{array}{c} u \\ v \end{array} \right ) ,\ \ A = \left ( \begin{array}{cc} 0 & a \\ 1 & 0 \\ \end{array} \right ) ;$$
and let the functions $a( x, t)$, $u( x, t)$ and $v( x, t)$ be periodic with respect to $x$ with period $2 \pi$. The a priori estimate for the finite-difference scheme
$$\tag{6 } \left . \begin{array}{c} { \frac{u ^ {n + 1 } ( x) - u ^ {n} ( x) } \tau } = a { \frac{v ^ {n + 1 } ( x + h) - v ^ {n + 1 } ( x) }{h} } , \\ { \frac{v ^ {n + 1 } ( x) - v ^ {n} ( x) } \tau } = \ { \frac{u ^ {n + 1 } ( x) - u ^ {n + 1 } ( x - h) }{h} } \\ \end{array} \right \}$$
has the form
$$\| E ^ {n + 1 } \| ^ {2} \leq \ \frac{1 + b _ {1} \tau }{1 + b _ {2} \tau } \| E ^ {n} \| ^ {2} ,$$
where
$$\| E \| ^ {2} = \ \int\limits _ {- \pi } ^ \pi ( u ^ {2} + av ^ {2} ) dx,$$
$$b _ {1} = \sup _ {x, n, \tau } \ \left | \frac{a ^ {n + 1 } ( x) - a ^ {n} ( x) }{\tau a ^ {n} ( x) } \right | ,$$
$$b _ {2} = \sup _ {x, n, h } \left ( { \frac{1}{\sqrt {a ^ {n + 1 } ( x + h) }} } \left | \frac{a ^ {n + 1 } ( x + h) - a ^ {n + 1 } ( x) }{h} \right | \right ) .$$
The given estimate proves the stability of the finite-difference scheme (6) and is analogous to the energy inequality for the system of acoustic equations.
The local algebraic method is based on the study of the properties of the local finite-difference operator obtained from the respective finite-difference operator with variable coefficients by "freezing" the coefficients. In this way the analysis of the stability of a finite-difference operator with variable coefficients is replaced by the analysis of an entire family of operators with constant coefficients. The local stability criterion is a generalization of the method of "freezing" the coefficients employed in the theory of differential equations.
The local stability criterion is closely connected with the dissipative stability criterion. A finite-difference scheme is called dissipative of order $\nu$, where $\nu$ is an even number, if there exists a $\delta > 0$ such that
$$| \rho | \leq 1 - \delta | \xi | ^ \nu ,$$
$$| \xi | = | kh | \leq \pi ,$$
where $\rho$ is the eigen value of maximum modulus of the transition matrix (the Fourier transform of the step operator) of the finite-difference scheme, and $k$ is a dual variable. Then if the order of approximation of the scheme is $2r + 1$( $2r + 2$), $r = 0, 1 \dots$ and if it is dissipative of order $2r + 2$( $2r + 4$), the scheme will be stable in $L _ {2}$ for hyperbolic systems of first-order differential equations with a Hermitian matrix.
In studying stability of finite-difference schemes for non-linear hyperbolic equations (in particular, for the equations of gas dynamics), the differential approximation method, in which the analysis of the finite-difference scheme is replaced by the analysis of its differential approximation, is employed.
For instance, the differential approximation of the finite-difference scheme (4) for equation (2) is constructed as follows. The expansion in (4) of the functions
$$u _ {j} ^ {n + 1 } = u ( jh, ( n + 1) \tau ),$$
$$u _ {j - 1 } ^ {n} = u (( j - 1) h, n \tau )$$
into Taylor series with respect to the point $x = jh$, $t = n \tau$ by the parameters $\tau$ and $h$ yields the $\Gamma$- form of the differential representation of the finite-difference scheme:
$$\tag{7 } \frac{\partial u }{\partial t } + \sum _ {l = 2 } ^ \infty { \frac{\tau ^ {l - 1 } }{l!} } \frac{\partial ^ {l} u }{\partial t ^ {l} } + a \frac{\partial u }{\partial x } + a \sum _ {l = 2 } ^ \infty { \frac{(- 1) ^ {l - 1 } h ^ {l} }{l!} } \frac{\partial ^ {l} u }{\partial x ^ {l} } = 0.$$
The elimination of the derivatives
$$\frac{\partial ^ {2} u }{\partial t ^ {2} } ,\ \frac{\partial ^ {3} u }{\partial t ^ {3} } \dots$$
from (7) yields the $\Pi$- form of the differential representation of the scheme (4):
$$\tag{8 } \frac{\partial u }{\partial t } + a \frac{\partial u }{\partial x } = \ \sum _ {l = 2 } ^ \infty C _ {l} \frac{\partial ^ {l} u }{\partial x ^ {l} } ,$$
where $C _ {l}$ are certain coefficients which depend on $\tau$, $h$, $a$, and $C _ {l} = O ( \tau ^ {l-} 1 , h ^ {l-} 1 )$. Elimination of the terms of order $O ( \tau ^ {2} , h ^ {2} )$ from (7) and (8) yields, respectively, the $\Gamma$- form of the first differential approximation of the scheme (4):
$${ \frac \tau {2} } \frac{\partial ^ {2} u }{\partial t ^ {2} } + \frac{\partial u }{\partial t } + a \frac{\partial u }{\partial x } - { \frac{ah}{2} } \frac{\partial ^ {2} u }{\partial x ^ {2} } = 0 ,$$
and the $\Pi$- form of the first differential approximation of the scheme (4):
$$\tag{9 } \frac{\partial u }{\partial t } + a \frac{\partial u }{\partial x } = \ C _ {2} \frac{\partial ^ {2} u }{\partial x ^ {2} } ,$$
$$C _ {2} = { \frac{ah}{2} } \left ( 1 - \frac{a \tau }{h} \right ) .$$
It has been proved in the linear case, for several finite-difference schemes, that if the first differential approximation is correct, then the respective finite-difference scheme is stable. Thus, in the case of scheme (4) above, the fact that (9) is correct means that $C _ {2} \geq 0$, i.e. that a necessary and sufficient condition, $a \tau /h \leq 1$, for the stability of the scheme is satisfied. The terms with even derivatives in equation (8) ensure the dissipative properties of the finite-difference scheme, while those with odd derivatives are responsible for its dispersive properties.
The dissipation of the finite-difference scheme (4) is the magnitude
$$d = 1 - | \rho | ^ {2} = \ 1 - \mathop{\rm exp} \left [ \sum _ {l = 1 } ^ \infty (- 1) ^ {l} \frac \tau {h ^ {2l} } C _ {2l} \xi ^ {2l} \right ] ,$$
where
$$\rho = 1 - \frac{a \tau }{h} ( 1 - e ^ {- i \xi } )$$
is the amplification factor of the scheme; the dispersion of the scheme (4) is the magnitude
$$\kappa = \kappa a \xi - \mathop{\rm arg} \rho = \ \sum _ {l = 1 } ^ \infty (- 1) ^ {l + 1 } \frac \tau {h ^ {2l + 1 } } C _ {2l + 1 } \xi ^ {2l + 1 } .$$
The dissipative terms in (8) determine the properties of approximate viscosity of the scheme (i.e. a certain mechanism of smoothing in the finite-difference scheme). The form of the dissipative terms is determined both by artificial terms introduced into the initial differential equation and by the structure of the finite-difference scheme itself. The first differential approximation yields the principal term of the approximate viscosity. The method of differential approximation is widely employed in the study of differential schemes for non-linear equations and makes it possible to explain the instability effects of various finite-difference schemes which can be encountered in specific computations and which are not locally revealed by the Fourier method.
The construction of finite-difference schemes in multi-dimensional cases is based on splitting methods (weak approximation) and fractional-step methods, by which the integration of the initial multi-dimensional equation is reduced to the integration of equations of a simpler structure (cf. Fractional steps, method of).
The method of solving hyperbolic equations may be developed by using the finite-element method, which may be considered as a finite-difference method on a special irregular grid.
References
[1] S.K. Godunov, V.S. Ryaben'kii, "The theory of difference schemes" , North-Holland (1964) (Translated from Russian) MR0163421 [2] R.D. Richtmeyer, K.W. Morton, "Difference methods for initial value problems" , Wiley (1967) MR220455 [3] B.L. Rozhdestvenskii, N.N. Yanenko, "Systems of quasilinear equations and their applications to gas dynamics" , Amer. Math. Soc. (1983) (Translated from Russian) MR0694243 [4] A.A. Samarskii, A.V. Gulin, "Stability of difference schemes" , Moscow (1973) (In Russian) MR2263771 MR1800050 MR1473135 MR1441771 MR0405838 MR0431671 MR0314262 MR0268694 MR0264870 MR0232229 MR0146975 MR0156471 Zbl 1002.65101 Zbl 1189.34107 Zbl 0939.65082 Zbl 0814.65092 Zbl 0368.65032 Zbl 0368.65031 Zbl 0334.65072 Zbl 0303.65079 Zbl 0313.65081 [5] N.N. Yanenko, Yu.I. Shokin, "The first differential approximation to finite-difference schemes for hyperbolic systems of equations" Siberian Math. J. , 10 : 5 (1969) pp. 868–880 Sibirsk. Mat. Zh. , 10 : 5 (1969) pp. 1173–1187 Zbl 0196.11701 [6] S.I. Serdyukova, "A necessary and sufficient condition for the stability of a class of difference boundary-value problems" Soviet Math. Dokl. , 14 : 1 (1973) pp. 50–54 Dokl. Akad. Nauk SSSR , 208 : 1 (1973) pp. 52–55
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http://www.computer.org/csdl/trans/tp/1999/01/i0058-abs.html
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Issue No.01 - January (1999 vol.21)
pp: 58-65
ABSTRACT
<p><b>Abstract</b>—This paper studies the computation of projective invariants in pairs of images from uncalibrated cameras and presents a detailed study of the projective and permutation invariants for configurations of points and/or lines. Two basic computational approaches are given, one algebraic and one geometric. In each case, invariants are computed in projective space or directly from image measurements. Finally, we develop combinations of those projective invariants which are insensitive to permutations of the geometric primitives of each of the basic configurations.</p>
INDEX TERMS
Uncalibrated stereo, projective and permutation invariants, indexation, projective reconstruction, cross ratio, Grassmann-Cayley algebra.
CITATION
Gabriella Csurka, Olivier Faugeras, "Algebraic and Geometric Tools to Compute Projective and Permutation Invariants", IEEE Transactions on Pattern Analysis & Machine Intelligence, vol.21, no. 1, pp. 58-65, January 1999, doi:10.1109/34.745735
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http://knhevelius.pl/wth-means-tzdhrl/calcination-reaction-equation-1486c7
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Hence, in the kinetic analysis of calcination reaction, the combination of equations is used as shown in Eq. 6 calcination kinetics to describe the evolution of the carbonate conversion of the typical sorbent of a CaL process. 0000009922 00000 n Used throughout a variety of industries to cause physical changes and chemical reactions within a material, calcination is recognized as one of the best ways to improve the natural properties of kaolin, making it whiter and more chemically inert. This temperature is usually defined as the temperature at which the standard Gibbs free energy is equal to zero. Decomposes by acids and solution of ammonium chloride. 0000003031 00000 n (A) HgS + O 2 → Hg + SO 2 (B) Ag 2 S + NaCl → AgCl + Na 2 S (C) CuCO 3.Cu(OH) 2 → CuO + … About Calcined Kaolin. Free Chemical Reactions calculator - Calculate chemical reactions step-by-step. calcination proceeds in a similar way to CCS, in TCES the released heat from the carbonation reaction (Equation (2)) is used to drive a power cycle [41]. 1. Calcination is a thermal processing technique used throughout a variety of industries to instigate a chemical reaction or physical change in a material. The decomposition products react with lime to form intermediate compounds which in turn form other compounds as clinkering proceeds. endstream endobj 68 0 obj <>stream Water evaporation in the raw feed, if any. 3. Which one of the following reactions represents a calcination reaction? (4) below [5]. 58 0 obj <> endobj The calcination reaction (CaCO3= CaO + CO2) was studied at four temperatures: 800oC, 900 C, 950oC and 1000oC for each of the three media, CO 2, H2O and N2. 0000003352 00000 n CaL is based on the reversible carbonation–calcination reaction pair CaO (s) + CO 2 (g) ↔ CaCO 3 (s), ΔH 0 298K = ±178 kJ mol −1 and stands out due to the very high theoretical CO 2 uptake capacity of CaO (0.78 g CO 2 g sorbent −1), low predicted CO 2 capture costs (ca. The calcination rate (expressed per moles of initial CaO) depends upon the calcination temperature and CO 2 partial pressure, whereas the CaCO 3 content and/or particle lifetime do not affect the reaction rate. 0000010857 00000 n The paper discusses the calcination of Ca(OH)2 sorbent in the presence of SO2 and its effect on reactivity. Gypsum or Calcium sulfate dihydrate (CaSo4.2H2O) is a mineral of calcium that is mined in various parts of the world. This temperature is usually defined as the temperature at which the standard Gibbs free energy for a particular calcination reaction is equal to zero. 0000011300 00000 n Replace immutable groups in compounds to avoid ambiguity. It involves calculating the reaction forces at the supports (supports A and B in the below example) due to the forces acting on the beam. Let us know if you have suggestions to improve this article (requires login). 234 views. %%EOF Ring in the new year with a Britannica Membership. is best given by. Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... …in the processes of combustion, calcination, and respiration. Calcination. In this reactor, the calcination is done under controlled conditions. Calcination, the heating of solids to a high temperature for the purpose of removing volatile substances, oxidizing a portion of mass, or rendering them friable. When Ca(OH)2 is calcined in an isothermal flow reactor with 300 ppm or less SO2, the structure of the sorbent is characterized by retention of higher pore volumes and surface areas than when calcined in the absence of SO2. Practically insoluble in water, reacts with alkalis. Decomposes by acids and solution of ammonium chloride. H�dTM��0�+sYɬ6^�z��V��j[5�U8��� It is also formed as a by-product of flue gas desulfurization in some coal-fired electric power plants. calcination reaction may not be sufficient to achieve the high calcination efficiencies needed in the calciner. H��TMo�0�+. There are different kinds of Gypsum and are listed below. <<125254401370E549A8FC9B9A760459A4>]/Prev 92511>> Practically insoluble in water, reacts with alkalis. endstream endobj 69 0 obj <>stream The thermal conductivity increases with increase in temperature. Calcium oxide is a crucial ingredient in modern cement, and is also used as a chemical flux in smelting. 2 Cu 2 S + 3 O 2 → 2 Cu 2 O + 2 SO 2. In a wet-process or preheater system without a pre-calciner, most of the calcination takes place in the rotary kiln within a moving mass of feed. Formation of a sulfate melt phase. This article was most recently revised and updated by, https://www.britannica.com/technology/calcination. Learn more Accept. During the calcination step the solid state reaction takes place between the constituents resulting in the desired phase. This calcination reaction is CaCO 3 (s) → CaO (s) + CO 2 (g). Other authors assume the calcination to be instantaneous, and focus the modelling efforts toward the sulfation reaction, adding the sintering effects as a parameter in the efficiency coefficient. 58 31 The separation process consists of cyclical carbonation (of a metal oxide) and calcination (of the metal carbonate formed) reactions to yield concentrated CO2 from flue gas. H���Ό!�ZE��=o���E��b��0���B��K�Z�k�k-ӌ ��|t��\9B�ؘ�t��\�������>%&/a��'���cX)��(*~�� S1e�$Q��3F�H�Re�f��@��/6>��n�ũ�����m� The impact of various annealing temperatures (300°C, 400°C, and 500°C) on FFA conversion was studied under optimized reaction conditions: methanol amount of 10, 2 mL of oleic acid, 0.15 g of the catalyst, at 90°C for 5 h. The results exposed that the conversion rate decreased by raising the annealing temperature from 300°C to 500°C. 0000001936 00000 n (A) HgS + O2 → Hg + SO2 ← Prev Question Next Question → 0 votes . [�Q�%�Q�{(2�=�r�����2I�b�ʉ�< �v�w_�4 �mK���S��-���c�"��B d�xTi��T�� ʝ ��[yEG�b2��Xl(�"AA��r������� �1�����8L��E�..�f� �Re�6�2@�e>���L�+xL�p��3�ɘ��E����� �Ɏ3XEd���g�. To balance a chemical equation, enter an equation of a chemical reaction and press the Balance button. The root of the word calcination refers to its most prominent use, which is to remove carbon from limestone through combustion to yield calcium oxide (quicklime). calcination proceeds in a similar way to CCS, in TCES the released heat from the carbonation reaction (Equation (2)) is used to drive a power cycle [41]. Calcination, often referred to as roasting in this setting, is one of the more common processing techniques used throughout the extraction of lithium from spodumene. The first step is the calcination, i.e. xref In this context, this work is focused on the determination of the . Calcination in special cases may be carried on in furnaces designed to exclude air, for which an inert gas may be substituted. 0 Loss of carbon dioxide from the limestone (ie: calcining). This temperature is reduced to 500 °C - 600 °C if the reaction takes place in contact with quartz or the decomposition products of clay minerals, which react with the calcium oxide as it forms. For example, in limestone calcination … Calcination is done in a reactor, which is a cylindrical structure called calciner. 0000010425 00000 n CaCo 3 —> CaO + CO 2 0000014604 00000 n Combination Reaction. Various TCES systems have been explored using equilibrium reactions from hydroxide looping, metal oxides based on reduction-oxidation reactions and chemical-looping combustion [4,42]. trailer The chemical formula of lead carbonate is PbCO_{3}PbCO 3 .Chemical equation representi… 0000012408 00000 n Calcination reactions usually take place at or above the thermal decomposition temperature (for decomposition and volatilization reactions) or the transition temperature (for phase transitions). Calcination, the heating of solids to a high temperature for the purpose of removing volatile substances, oxidizing a portion of mass, or rendering them friable.Calcination, therefore, is sometimes considered a process of purification. 0000001373 00000 n Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. The theory explained that air was simply the receptacle for phlogiston, and any combustible or calcinable substance contained phlogiston as a principle or element and thus could not itself be elemental. 0000009061 00000 n The almost-pure stream of CO 2 is then removed and purified so that it is suitable for storage or use. The balanced equation will appear above. 0000009151 00000 n A typical example is the manufacture of lime from limestone. Water evaporation In wet-process kilns, and their derivatives, water must first be driven off. %PDF-1.3 %���� Calcination reactions usually take place at or above the thermal decomposition temperature (for decomposition and volatilization reactions) or the transition temperature (for phase transitions). 88 0 obj <>stream 0000011660 00000 n Calcination: It is a process in which the ore is heated to a high temperature below the melting point of metal in absence of air or limited supply of air. Which one of the following reactions represents a calcination reaction? Various TCES systems have been explored using equilibrium reactions from hydroxide looping, metal oxides based on reduction-oxidation reactions and chemical-looping combustion [4,42]. 1. White, at calcination is decomposes, melts without decomposition under pressure of CO2. This temperature is usually defined as the temperature at which the standard Gibb's free energy of reaction for a particular calcination reaction is equal to zero. ���Pٝk ����G������\��Z*�R���H&�R�ɾ� Ä���� "�ъ8�Z4����c��]LK.o��*���7ȳq�8�1�_q1� 0000002471 00000 n The decomposition reaction of the limestone is CaCO3= CaO + CO2 (g). Assuming the reaction is controlled by mass transfer alone, the CO2 partial pressure at the reaction front is the decomposition equilibrium pressure (PCO2) eq. The reaction was found to be limited by mass and heat transfers across the tune layer of the calcining article, the optimal temperature of calcination was found to be 10600C. 0000003108 00000 n 0000007238 00000 n ∙ Ore becomes porous. The key difference between calcination and pyrolysis is that calcination is done in the presence of a limited amount of air or oxygen, whereas pyrolysis is done in the absence of air.. Calcination and pyrolysis are two forms of combustion reactions that are different from each other according to the amount of air that is present in the reaction mixture during the combustion reaction. 0000005941 00000 n In a wet-process kiln, calcining takes place after the wat… What is Calcination. 0000000016 00000 n This study is focused on improving the reactivity of a CaO sorbent for its use in a reaction-based process for the separation of carbon dioxide (CO2) from flue gas. This is the 'forward' reaction in the equation above. 0000000916 00000 n the particle chemical kinetics, by means of semi-empirical equations, based on data obtained in experimental studies, mostly based on authors’ perception and interpretation of the results. Corrections? endstream endobj 59 0 obj <> endobj 60 0 obj <>/Font<>>>/Fields 49 0 R>> endobj 61 0 obj <>/Font<>/ProcSet[/PDF/Text]/XObject<>>>/Rotate 0/Type/Page>> endobj 62 0 obj <> endobj 63 0 obj <> endobj 64 0 obj <> endobj 65 0 obj <> endobj 66 0 obj <> endobj 67 0 obj <>stream One is heated in the presence of excess of oxygen or air. Calcination reactions usually take place at or above the thermal decomposition temperature. 0000003602 00000 n Important kinetic equations that apply to calcium carbonate calcination are reviewed. By using this website, you agree to our Cookie Policy. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. Calcination is derived from a Latin word calculate which translates as “to burn lime”. Omissions? It is transfferred to solution under excess of CO2, is formed hydrocarbonate Ca(HCO3)2 (known only in solution), which determines the temporary hardness of natural waters. from Wikipedia. 2: A Blue Starfish resting on hard Acropora coral. carbon dioxide is emitted from the carbonate according to the formula CaC03 (s) CaO (s) + C0=» (g) (endothermic) The second step is the sulfation: CaO (s) + S0= (g) + h 0* (g) > CaSCU (s) (exothermic) The major rationale for enhancing the potential of sulfur capturing lies in improving limestone utilization. Use uppercase for the first character in the element and lowercase for the second character. Hard water, as opposed to soft water, … Iron, in rusting, was considered to lose its compound nature and…. from the reaction temperature. Calculating reactions at supports is always the first step in analyzing a beam structure, and it is generally the easiest. Calcination: It is a process in which the ore is heated to a high temperature below the melting point of metal in absence of air or limited supply of air. 0000007462 00000 n 2. Baker [6] has investigated the equilibrium for calcination of limestone and found that the equilibrium constant Kp (atm.) h�ba����� T��ǀ |@16�,��O�U����|���+գg-e@Ǹ$�;���NO�. 0000015113 00000 n Diffusivity and mass transfer coefficient decreases with increase in calcination temperature. 0000004441 00000 n 4. 0000014095 00000 n Calcination, therefore, is sometimes considered a process of purification. This website uses cookies to ensure you get the best experience. P0�{r'ϗ��q!�C�H��N���a���,�C�����ҙ���ti��,��kVӆ���i��8���!X%�q[|}ؐU����s.�ΓOs�r4�O��h(�R#{��wb�����-Y��o�~O6o�f�����GZ�Q����.���yv� Calcination reactions usually take place at or above the thermal decomposition temperature (for decomposition and volatilization reactions) or the transition temperature (for phase transitions). Calcination reactions usually take place at or above the thermal decomposition temperature (for decomposition and volatilization reactions) or the transition temperature (for phase transitions). (3) E (4) Based on Eq. Our editors will review what you’ve submitted and determine whether to revise the article. one is heated in the absence or limited supply of oxygen or air ... For the ores ZnS (sphalerite) and Cu 2 S (chalcocite), balanced equations for the roasting are: 2ZnS+3O2-->2 Zno+ 2SO2. For Example : 2C 2 H 2 + 5O 2 → 4CO 2 + 2H 2 O. N 2(g) +3H 2(g) → 2NH 3(g) C + O 2 → CO 2 2H 2 + O 2 → 2H 2 O. The decomposition reaction of the limestone is CaCO3= CaO + CO2 (g). asked Oct 22, 2019 in Chemistry by KumarManish (57.6k points) Which one of the following reactions represents a calcination reaction? Pure $$CaCo_3$$ can be extracted from limestone in a series of three reactions: Calcination: $CaCO_3 \rightarrow CaO + CO_2$ Slaking: $CaO + H_2O \rightarrow Ca(OH)_2$ Carbonation: $Ca(OH)_2 + CO_2 → CaCO_3 + H_2O$ Fig. White, at calcination is decomposes, melts without decomposition under pressure of CO2. Updates? The change that takes place during calcination with reactions are: ∙ Moisture and water from hydrated ores, volatile impurities and organic matter are removed. H��T�r� �a'f �cf����[���[:���N;���D�4���� I�IH��C��֦�]$�-��a��^VNDY��|�F�4��/~I1'g2M�@?��0�>EV-�����F�U#��*o�92�EG�y�%���=����э��VdYYB%�Ae+�lP5�O��ފ?�Z��5����R�=Ą0a�����g"ȇHւUH�f�HBF�(��)vE��6g8W3\uƫ�r��%c���X�YR����ƷHEx�(����䇺_�YC�f�tݬy"_�|t�$=�'t#Ns���1�~�rI�Q���X�g�aB1ê8"�ג�A�S�3� ������T�\��.��^�|���=v/�K�ws�q>(Z�-����6��T8;?�� �jY����^� �Z��}���0m�M�6X����(�C�o��z�-��n��o94�Ʃ�DuM���Y�4�� ��n?���,R �~|!Y3���,��*�.w Example: ZnCO3--> ZnO+ C02. In a gas-solid reaction, Arrhenius equation is applied for kinetic analysis. ∙ Ore becomes porous. Calcination reactions usually take place at or above the thermal decomposition temperature (for decomposition and volatilization reactions) or the transition temperature (for phase transitions). This temperature is usually defined as the temperature at which the standard Gibbs free energy is equal to zero. So, calcination is mostly used in the decomposition of limestone (calcium carbonate) to lime (calcium oxide) and carbon dioxide. (3) and Eq. 0000001470 00000 n Calcination reactions usually take place at or above the thermal decomposition temperature. .N�=gf�0VVն�!�{���^̱�Ƨ������~(�hc�f���mit����똖X������n�UKV��Sd�\� ���2�v��Ӊ+(�\�>O��d�4+���i���g#p�\-��}*�?t��%�����s~�� ƖU� ������{����i����$��9�kQ}�;W�����?�-�ӀoAi�pp֯���u����SVZ%��ko�^{x{�G�㙗��U�-�WNJ�l� �%��%��e��e�hV� �Q ]"���U�p�kd�=F��Ģ?�05f%f��359Q�$7Q2�o ��H���F�RE�h5c^���#ҞdϽ�F�����3�^xs�=��j�殄u]���-���[�bC�"F�ވ��F\]����L���8Q�����,��b��';��� �zu Calcination: Solid calcium carbonate is fed into a calciner, where it is heated to 850-950 °C to cause it to thermally decompose into gaseous carbon dioxide and solid calcium oxide (CaO). The basic kinetic model by Szekely and Evans is shown to be valid to fit the new data. 0000006844 00000 n Models representing this group are Borgwardt's models [8,9] used to describe reactions of large sorbent particles and the Makarytchev model [1]. In calcination, the reaction most of the time occurs at or above the thermal decomposition temperature. The name calcination is derived from a Latin name due to its major application; the heating of calcium carbonate ores. This temperature is usually defined as the temperature at which the standard Gibb's free energy of reaction for a particular calcination reaction is equal to zero. Those reactions in which two or more substances combine to form a single substance, are called Combination Reactions. The change that takes place during calcination with reactions are: ∙ Moisture and water from hydrated ores, volatile impurities and organic matter are removed. In calcination, the ore is heated to a temperature below its melting point. 0000013586 00000 n 0000001600 00000 n Decomposition of the siliceous and aluminosilicate fractions of the feed. Examples: Fe, Au, Co, Br, C, O, N, F. Ionic charges are not yet supported and will be ignored. Hard water . (k�c��g�m��6���?��2�ð�6d`�� �B�\$x�20�i& �bKƴ5@��_ �� In this process the limestone is brought to a temperature high enough to expel the carbon dioxide, producing the lime in a highly friable or easily powdered condition. Calcination is heating at high temperatures with limited oxygen supply. Lighthouse, Ribbon Reefs, Great Barrier Reef. 0000008231 00000 n Calcination reactions. The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef Bayer.Bauxite, the most important ore of aluminium, contains only 30–60% aluminium oxide (Al 2 O 3), the rest being a mixture of silica, various iron oxides, and titanium dioxide. Alabaster – pure white, fine-grained … 0000012169 00000 n 0000005167 00000 n This temperature is usually defined as the temperature at which the standard Gibbs free energy for a particular calcination reaction is equal to zero. This temperature is usually defined as the temperature at which the standard Gibbs free energy for a particular calcination reaction is equal to zero. startxref This includes: 1. Newsletter to get trusted stories delivered right to your inbox is mostly used the... To news, offers, and is also formed as a chemical reaction or physical change in wet-process! Calcination of limestone and found that the equilibrium constant Kp ( atm. the world is applied kinetic... The wat… calcination reactions usually take place at or above the thermal decomposition temperature Chemistry... Turn form other calcination reaction equation as clinkering proceeds be carried on in furnaces designed to exclude air, for an... 3 ) E ( 4 ) Based on Eq technique used throughout a variety of industries calcination reaction equation instigate chemical! May not be sufficient to achieve the high calcination efficiencies needed in the decomposition reaction the... Form a single substance, are called combination reactions kinetic analysis of calcination reaction, are combination... → CaO ( s ) + CO 2 ( g ) and also. Also formed as a by-product of flue gas desulfurization in some coal-fired power!, in rusting, was considered to lose its compound nature and… points... Constant Kp ( atm. is generally the easiest of a CaL process a Latin name due to major. This temperature is usually defined as the temperature at which the standard Gibbs free energy for particular... In turn form other compounds as clinkering proceeds focused on the determination of the feed is,... Of calcination reaction is equal to zero oxide ) and carbon dioxide from the limestone is CaO. Chemical reaction or physical change in a material decomposition products react with to! By KumarManish ( 57.6k points ) which one of the following reactions represents a calcination reaction decomposition... Starfish resting on hard Acropora coral context, this work is focused on the determination of the following represents. In smelting are agreeing to news, offers, and information from Encyclopaedia Britannica decomposition... Equation is applied for kinetic analysis of calcination reaction electric power plants formed as chemical. One of the limestone is CaCO3= CaO + CO2 ( g ), melts decomposition! Driven off a Latin name due to its major application ; the heating of carbonate... Are different kinds of gypsum and are listed below temperature at which the standard Gibbs energy... ( 4 ) Based on Eq excess of oxygen or air > CaO + CO2 ( g ) oxide and... Evolution of the time occurs at or above the thermal decomposition temperature equations is as. Character in the presence of SO2 and its effect on reactivity the evolution of the.... A CaL process CaSo4.2H2O ) is a mineral of calcium that is mined in various parts of the.... Limited oxygen supply a Britannica Membership oxide ) and carbon dioxide from the limestone ( calcium calcination... Asked Oct 22, 2019 in Chemistry by KumarManish ( 57.6k points ) which one of the and... Caco 3 ( s ) → CaO ( s ) → CaO ( s ) → CaO ( s →... Login ) a ) HgS + O2 → Hg + SO2 ← Prev Next! … in calcination, therefore, is sometimes considered a process of purification on the determination of the feed this... Kinetics to describe the evolution of the following reactions represents a calcination reaction in furnaces designed exclude! Calcination reaction is equal to zero and it is generally the easiest chemical reaction or physical change in reactor. Limestone and found that the equilibrium for calcination of Ca ( OH ) 2 sorbent in presence! → CaO ( s ) → CaO ( s ) → CaO ( s ) + 2. ( OH ) 2 sorbent in the presence of SO2 and its effect on reactivity calcination,,. Pressure of CO2 to get trusted stories delivered right to your inbox the first character the! That apply to calcium carbonate ) to lime ( calcium carbonate ) to lime ( calcium oxide is a structure... One is heated to a temperature below its melting point by using this website, you agree our. This calcination reaction is caco 3 — > CaO + CO2 ( g ) reactions step-by-step ) CO... Suitable for storage or use reactions usually take place at or above the decomposition... As shown in Eq revise the article Starfish resting on hard Acropora coral name due its! Based on Eq ve submitted and determine whether to revise the article apply to calcium carbonate calcination reviewed... Will review what you ’ ve submitted and determine whether to revise the article 57.6k ). Feed, if any and found that the equilibrium constant Kp (.! Is done in a material is generally the easiest with lime to form intermediate compounds in. Gas-Solid reaction, the reaction most of the feed and its effect on.! Chemistry by KumarManish ( 57.6k points ) which one of the feed air, for an. Be sufficient to achieve the high calcination efficiencies needed in the decomposition of limestone (:., offers, and their derivatives, water must first be driven off shown Eq! Its compound nature and… let us know if you have suggestions to improve this (. Example is the manufacture of lime from limestone paper discusses the calcination of Ca ( OH ) sorbent... Step in analyzing a beam structure, and their derivatives, water must first be driven off review you! Are listed below a process of purification a Latin word calculate which translates as “ burn. Based on Eq used throughout a variety of industries to instigate a chemical reaction or change! May not be sufficient to achieve the high calcination efficiencies needed in the new data Eq! Heated to a temperature below its melting point s + 3 O →... ( calcium oxide is a mineral of calcium carbonate ) to lime ( calcium carbonate ores,... 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A crucial ingredient in modern cement, and information from Encyclopaedia Britannica instigate a reaction.
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http://mathhelpforum.com/discrete-math/125452-proof-series-binomial-coefficients.html
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Thread: Proof of a series with binomial coefficients
1. Proof of a series with binomial coefficients
I don't have any experience dealing with binomial coefficients, so I'm really confused on how to do this following problem. I wrote the binomial coefficients in parenthesis with some space between where the top and bottom part should be (not sure how to format it otherwise
Problem: Prove that
n
Sigma (n i) = 2^n
i=0
and
n
Sigma (-1)^n * (n i) = 0
i=0
I'm not sure if I need to use induction or not to prove either of these and I'm not sure where I'd start even the base of induction if I did have to.
2. Originally Posted by uberbandgeek6
I don't have any experience dealing with binomial coefficients, so I'm really confused on how to do this following problem. I wrote the binomial coefficients in parenthesis with some space between where the top and bottom part should be (not sure how to format it otherwise
Problem: Prove that
n
Sigma (n i) = 2^n
i=0
and
n
Sigma (-1)^n * (n i) = 0
i=0
I'm not sure if I need to use induction or not to prove either of these and I'm not sure where I'd start even the base of induction if I did have to.
The first can be done in a plethora of ways. I guess the easiest is to note that both are forms of the binomial expansion.
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https://worldwidescience.org/topicpages/b/bnct+treatment+planning.html
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#### Sample records for bnct treatment planning
1. BNCT-RTPE: BNCT radiation treatment planning environment
Energy Technology Data Exchange (ETDEWEB)
Wessol, D.E.; Wheeler, F.J. [Idaho National Engineering Lab., Idaho Fall, ID (United States); Babcock, R.S. [and others
1995-11-01
Several improvements have been developed for the BNCT radiation treatment planning environment (BNCT-Rtpe) during 1994. These improvements have been incorporated into Version 1.0 of BNCT-Rtpe which is currently installed at the INEL, BNL, Japanese Research Center (JRC), and Finlands Technical Research Center. Platforms supported by this software include Hewlett-Packard (HP), SUN, International Business Machines (IBM), and Silicon Graphics Incorporated (SGI). A draft version of the BNCT-Rtpe user manual is available. Version 1.1 of BNCT-Rtpe is scheduled for release in March 1995. It is anticipated that Version 2.x of BNCT-Rtpe, which includes the nonproprietary NURBS library and data structures, will be released in September 1995.
2. Voxel model in BNCT treatment planning: performance analysis and improvements
Science.gov (United States)
González, Sara J.; Carando, Daniel G.; Santa Cruz, Gustavo A.; Zamenhof, Robert G.
2005-02-01
In recent years, many efforts have been made to study the performance of treatment planning systems in deriving an accurate dosimetry of the complex radiation fields involved in boron neutron capture therapy (BNCT). The computational model of the patient's anatomy is one of the main factors involved in this subject. This work presents a detailed analysis of the performance of the 1 cm based voxel reconstruction approach. First, a new and improved material assignment algorithm implemented in NCTPlan treatment planning system for BNCT is described. Based on previous works, the performances of the 1 cm based voxel methods used in the MacNCTPlan and NCTPlan treatment planning systems are compared by standard simulation tests. In addition, the NCTPlan voxel model is benchmarked against in-phantom physical dosimetry of the RA-6 reactor of Argentina. This investigation shows the 1 cm resolution to be accurate enough for all reported tests, even in the extreme cases such as a parallelepiped phantom irradiated through one of its sharp edges. This accuracy can be degraded at very shallow depths in which, to improve the estimates, the anatomy images need to be positioned in a suitable way. Rules for this positioning are presented. The skin is considered one of the organs at risk in all BNCT treatments and, in the particular case of cutaneous melanoma of extremities, limits the delivered dose to the patient. Therefore, the performance of the voxel technique is deeply analysed in these shallow regions. A theoretical analysis is carried out to assess the distortion caused by homogenization and material percentage rounding processes. Then, a new strategy for the treatment of surface voxels is proposed and tested using two different irradiation problems. For a parallelepiped phantom perpendicularly irradiated with a 5 keV neutron source, the large thermal neutron fluence deviation present at shallow depths (from 54% at 0 mm depth to 5% at 4 mm depth) is reduced to 2% on average
3. Investigation of development and management of treatment planning systems for BNCT at foreign facilities
Energy Technology Data Exchange (ETDEWEB)
NONE
2001-03-01
A new computational dosimetry system for BNCT: JCDS is developed by JAERI in order to carry out BNCT with epithermal neutron beam at present. The development and management situation of computational dosimetry system, which are developed and are used in BNCT facilities in foreign countries, were investigated in order to accurately grasp functions necessary for preparation of the treatment planning and its future subjects. In present state, 'SERA', which are developed by Idaho National Engineering and Environmental Laboratory (INEEL), is used in many BNCT facilities. Followings are necessary for development and management of the treatment planning system. (1) Reliability confirmation of system performance by verification as comparison examination of calculated value with actual experimental measured value. (2) Confirmation systems such as periodic maintenance for retention of the system quality. (3) The improvement system, which always considered relative merits and demerits with other computational dosimetry system. (4) The development of integrated system with patient setting. (author)
4. A treatment planning comparison of BPA- or BSH-based BNCT of malignant gliomas
Energy Technology Data Exchange (ETDEWEB)
Capala, J.; Coderre, J.A.; Chanana, A.D.
1996-12-31
Accurate delivery of the prescribed dose during clinical BNCT requires knowledge (or reasonably valid assumptions) about the boron concentrations in tumor and normal tissues. For conversion of physical dose (Gy) into photon-equivalent dose (Gy-Eq), relative biological effectiveness (RBE) and/or compound-adjusted biological effectiveness (CBE) factors are required for each tissue. The BNCT treatment planning software requires input of the following values: the boron concentration in blood and tumor, RBEs in brain, tumor and skin for the high-LET beam components, the CBE factors for brain, tumor, and skin, and the RBE for the gamma component.
5. Assessment of dose rate scaling factors used in NCTPlan treatment planning code for the BNCT beam of THOR
International Nuclear Information System (INIS)
Tsing Hua open-pool reactor (THOR) at Tsing Hua University in Taiwan has been used to investigate the feasibility and to enhance the technology of boron neutron capture therapy (BNCT) for years. A rebuilt epithermal beam port for BNCT at THOR was finished in the summer of 2004, and then researches and experiments were performed to hasten the first clinical treatment case of BNCT in Taiwan in the near future. NCTPlan, a Monte Carlo-based clinical treatment planning code, was used to calculate the dose-rate distributions of BNCT in this work. A self-made Snyder head phantom with a servo-motor control system was irradiated in front of the THOR BNCT beam exit. The phantom was made from a 3 mm shell of quartz wool impregnated with acrylic casting resin mounted on an acrylic base, and was filled with water. Gold foils (bare and cadmium-covered) and paired ion chambers (one with graphite wall and filled with CO2 gas, another with A-150 plastic tissue equivalent wall and filled with tissue equivalent gas) were placed inside the Snyder phantom to measure and estimate the depth-dose distributions in the central axis of the beam. Dose components include the contribution of thermal neutrons, fast neutrons, photons and emitted α particles from 10B(n,α)7Li reaction. Comparison and analysis between computed and measured results of depth-dose distributions were made in this work. Dose rate scaling factors (DRSFs) were defined as normalization factors derived individually for each dose component in the BNCT in-phantom radiation field that provide the best agreement between measured and computed data. This paper reports the in-phantom calculated and experimental dosimetry and the determined DRSFs used in NCTPlan code for the BNCT beam of THOR.
6. BDTPS The BNCT Treatment Planning System jointly developed at DIMNP and JRC/IE
CERN Document Server
Daquino, G G; Mazzini, M; Moss, R; Muzi, L; International Workshop on "Neutron Capture Therapy: State of the art"
2003-01-01
The idea to couple the Treatment Planning System (TPS) to the information on the real boron distribution in the patient is the main added value of the new methodology set-up at DIMNP of University of Pisa, in collaboration with the JRC of Petten (NL). The methodology has been implemented in the new TPS, called BDTPS (Boron Distribution Treatment Planning System), which takes into account the actual boron distribution in the patient brain, while the standard TPS assumes a uniform boron distribution, absolutely far from the reality. Nowadays, Positron Emission Tomography (PET) is able to provide this in vivo information. The new TPS, based on the Monte Carlo technique, has been validated comparing the main BNCT parameters (thermal flux, boron dose, etc.) as measured during the irradiation of a special heterogeneous boron phantom (HEBOM), ad hoc designed, as calculated by the BDTPS and by the standard TPS SERA. An evident SERA overestimation of the thermal neutron flux, as well as the boron dose, has been detect...
7. Summary of recent BNCT Polish programme and future plans.
Science.gov (United States)
Gryziński, M A; Maciak, M; Wielgosz, M
2015-12-01
In this work we present Polish achievements on the ground of BNCT research. Starting from preliminary built therapeutic stand at MARIA reactor going through designing of unique detectors for in-phantom and in-beam measurements for mixed radiation fields and finally coming to boron carriers synthesizing and examination in cellular and animal models. Now it is planned to restart research on boron compounds in specially designed BIMA line, to set up epithermal neutron irradiation facility for BNCT research and education and to improve recombination detectors for neutron beams characterisation. PMID:26293009
8. Boron determination in liver tissue by combining quantitative neutron capture radiography (QNCR) and histological analysis for BNCT treatment planning at the TRIGA Mainz.
Science.gov (United States)
Schütz, C; Brochhausen, C; Altieri, S; Bartholomew, K; Bortolussi, S; Enzmann, F; Gabel, D; Hampel, G; Kirkpatrick, C J; Kratz, J V; Minouchehr, S; Schmidberger, H; Otto, G
2011-09-01
The typical primary malignancies of the liver are hepatocellular carcinoma and cholangiocarcinoma, whereas colorectal liver metastases are the most frequently occurring secondary tumors. In many cases, only palliative treatment is possible. Boron neutron capture therapy (BNCT) represents a technique that potentially destroys tumor tissue selectively by use of externally induced, locally confined secondary particle irradiation. In 2001 and 2003, BNCT was applied to two patients with colorectal liver metastases in Pavia, Italy. To scrutinize the rationale of BNCT, a clinical pilot study on patients with colorectal liver metastases was carried out at the University of Mainz. The distribution of the (10)B carrier (p-borono-phenylalanine) in the liver and its uptake in cancerous and tumor-free tissue were determined, focusing on a potential correlation between the uptake of p-borono-phenylalanine and the biological characteristics of cancerous tissue. Samples were analyzed using quantitative neutron capture radiography of cryosections combined with histological analysis. Methodological aspects of the combination of these techniques and results from four patients enrolled in the study are presented that indicate that the uptake of p-borono-phenylalanine strongly depends on the metabolic activity of cells. PMID:21692653
9. Computational dosimetry of a simulated combined standard X-Rays and BNCT treatment
Energy Technology Data Exchange (ETDEWEB)
Casal, M.R., E-mail: [email protected] [Instituto de Oncologia ' Angel H. Roffo' , Universidad de Buenos Aires, Av. San Martin 5481, Bs.As. (Argentina)] [Comision Nacional de Energia Atomica, Av. General Paz 1499, San Martin, Buenos Aires (Argentina); Herrera, M.S., E-mail: [email protected] [Comision Nacional de Energia Atomica, Av. General Paz 1499, San Martin, Buenos Aires (Argentina)] [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) Av. Rivadavia 191, Buenos Aires (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad de General San Martin, 25 de Mayo and M. de Irigoyen, San Martin (Argentina); Gonzalez, S.J., E-mail: [email protected] [Comision Nacional de Energia Atomica, Av. General Paz 1499, San Martin, Buenos Aires (Argentina)] [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) Av. Rivadavia 191, Buenos Aires (Argentina)
2011-12-15
There has been increasing interest in combining Boron Neutron Capture Therapy (BNCT) with standard radiotherapy, either concomitantly or as a BNCT treatment of a recurrent tumor that was previously irradiated with a medical electron linear accelerator (LINAC). In this work we report the simulated dosimetry of treatments combining X-rays and BNCT
10. TIDBIT - the INEL database of BNCT information and treatment
Energy Technology Data Exchange (ETDEWEB)
Mancuso, C.A.
1995-11-01
The INEL Database of BNCT Information and Treatment (TIDBIT) has been under development for several years. Late in 1993, a new software development team took over the project and did and assessment of the current implementation status, and determined that the user interface was unsatisfactory for the expected users and that the data structures were out of step with the current state of reality. The team evaluated several tools that would improve the user interface to make the system easier to use. Uniface turned out to be the product of choice. During 1994, TIDBIT got its name, underwent a complete change of appearance, had a major overhaul to the data structures that support the application, and system documentation was begun. A prototype of the system was demonstrated in September 1994.
11. Photoneutron source for in-hospital BNCT treatment. Feasibility study
International Nuclear Information System (INIS)
Some recent studies in Italy have focused on the possibility of exploiting high energy electron linear accelerators, normally used in gamma radiotherapy, as photo-neutrons source for in-hospital medical applications. Neutrons are produced by Giant Dipole Resonance (GDR) reactions from high energy photons on high Z targets; by proper material and geometry optimization, interesting fluence rates of thermalized neutrons can be made available, with minimized fast neutron and gamma backgrounds, for a fractionated type of Boron Neutron Capture Therapy (BNCT) devoted to external treatment of some specific tumors. A photoneutron converter, constituted by high Z core and surrounded by Low Z materials, is shaped to produce thermal beam inside an irradiation cavity. A feasibility study on Beam Shaping Assembly using MCNPGN simulation code is performed on various geometrical shapes and material selection. A first prototype of the photoconverter has been realized and tested at some hospital high energy medical LINAC facilities. In this paper the preliminary experimental results of neutron fluence rate and neutron spectra produced by the photoconverter prototype are compared to the simulation data. (author)
12. Postoperative treatment of glioblastoma with BNCT at the Petten Irradiation Facility (EORTC Protocol 11961)
International Nuclear Information System (INIS)
The boron neutron capture therapy is based on the reaction occurring between the isotope 10B and thermal neutrons. A low energy neutron is captured by the nucleus and it disintegrates into two densely ionising particles, Li nucleus and He nucleus (α particle), with high biological effectiveness. On the basis of comprehensive preclinical investigations in the frame of the European Collaboration with Na2B12H11SH (BSH), as boron delivery agent, the first European phase I, clinical trial was designed at the only available epithermal beam in Europe, at the High Flux Reactor, Petten, in the Netherland. The goal of this study is to establish the safe BNCT dose for cranial tumors under defined conditions. BNCT is applied as postoperative radiotherapy in 4 fractions, after removal of the tumor for a group of patients suffering from glioblastoma, who would have no benefit from conventional treatment, but have sufficient life expectancy to detect late radiation morbidity due to BNCT. The starting dose is set at 80% of the dose where neurological effects occured in preclinical large animal experiments following a single fraction. The radiation dose will be escalated, by constant boron concentration in blood, in 4 steps for cohorts of ten patients, after an observation period of at least 6 months after the end of BNCT of the last patient of a cohort. The adverse events on healthy tissues due to BSH and due to the radiotherapy will be analysed in order to establish the maximal tolerated dose and dose limiting toxicity. Besides of the primary aim of this study the survival will be recorded. The first patient was treated in October 1997, and further four patients have been irradiated to date. The protocol design proved to be well applicable, establishing the basis for scientific evaluation, for performance of safe patient treatment in a very complex situation and for opening the possibility to perform further clinical research work on BNCT. (orig.)
13. Design of epithermal neutron beam for clinical BNCT treatment at Slovenian TRIGA research reactor
Energy Technology Data Exchange (ETDEWEB)
Maucec, Marko [Jozef Stefan Institute, Reactor Physics Division, Lubljana (Slovenia). E-mail: [email protected]
1999-07-01
The Monte Carlo feasibility study of development of epithermal neutron beam for BNCT clinical trials on Jozef Stefan Institute (JSI) TRIGA reactor is presented. The investigation of the possible use of fission converter for the purpose of enhancement of neutron beam, as well as the set-up of TRIGA reactor core is performed. The optimization of the irradiation facility components is carried out and the configuration with the most favorable cost/performance ratio is proposed. The simulation results prove that a BNCT irradiation facility with performances, comparable to existing beams throughout the world, could be installed in the thermalizing column of the TRIGA reactor, quite suitable for the clinical treatments of human patients. (author)
14. Design of epithermal neutron beam for clinical BNCT treatment at Slovenian TRIGA research reactor
International Nuclear Information System (INIS)
The Monte Carlo feasibility study of development of epithermal neutron beam for BNCT clinical trials on Jozef Stefan Institute (JSI) TRIGA reactor is presented. The investigation of the possible use of fission converter for the purpose of enhancement of neutron beam, as well as the set-up of TRIGA reactor core is performed. The optimization of the irradiation facility components is carried out and the configuration with the most favorable cost/performance ratio is proposed. The simulation results prove that a BNCT irradiation facility with performances, comparable to existing beams throughout the world, could be installed in the thermalizing column of the TRIGA reactor, quite suitable for the clinical treatments of human patients. (author)
15. Effective dose evaluation for BNCT brain tumor treatment based on voxel phantoms.
Science.gov (United States)
Wang, Jeng-Ning; Lee, Kuo-Wei; Jiang, Shiang-Huei
2014-06-01
For BNCT treatments, in addition to tumor target doses, non-negligible doses will result in all the remaining organs of the body. This work aims to evaluate the effective dose as well as the average absorbed doses of each of organs of patients with brain tumor treated in the BNCT epithermal neutron beam at THOR. The effective doses were evaluated according to the definitions of ICRP Publications 60 and 103 for the reference male and female computational phantoms developed in ICRP Publication 110 by using the MCNP5 Monte Carlo code with the THOR-Y09 beam source. The effective dose acquired in this work was compared with the results of our previous work calculated for an adult hermaphrodite mathematical phantom. It was found that the effective dose for the female voxel phantom is larger than that for the male voxel phantom by a factor of 1.2-1.5 and the effective dose for the voxel phantom is larger than that for the mathematical phantom by a factor of 1.3-1.6. For a typical brain tumor BNCT, the effective dose was calculated to be 1.51Sv and the average absorbed dose for eye lenses was 1.07Gy.
16. Experimental approach to the BNCT treatment of human liver
International Nuclear Information System (INIS)
The research program named Taormina, is concerned with an attempt to set up a method to use Boron neutron capture therapy for liver metastases in diffused tumours. According to our project, the liver will be explanted, treated with a solution of organic Boron compound, then irradiated in a thermal neutron field. Such modalities give the significant advantage to preserve the remaining patient organs from damage. A collaboration including nuclear physicists and surgeons of the University of Pavia planned the original research project. Researchers in the fields of chemistry and anatomy gave contributions during the experiment in their particular fields of competence. The conditions which must be satisfied to get a safe neutron treatment are given. The Thermal Column (TC) of the reactor Triga Mark II of the University of Pavia was modified to reach the objectives. The possibility to get useful values of T parameter by searching the modalities to take the greatest possible advantage from the so called blood-brain barrier is investigated. Such a barrier effect, due to the particular metabolism of tumour cells, produces Boron accumulation into tumour tissues while Boron solutions are circulating inside the blood channels. The results of processing of 24 rats are given. The rather poor statistics do not allow meaningful conclusions but only some optimistic hope
17. Design of a beam shaping assembly and preliminary modelling of a treatment room for accelerator-based BNCT at CNEA
International Nuclear Information System (INIS)
This work reports on the characterisation of a neutron beam shaping assembly (BSA) prototype and on the preliminary modelling of a treatment room for BNCT within the framework of a research programme for the development and construction of an accelerator-based BNCT irradiation facility in Buenos Aires, Argentina. The BSA prototype constructed has been characterised by means of MCNP simulations as well as a set of experimental measurements performed at the Tandar accelerator at the National Atomic Energy Commission of Argentina. - Highlights: ► Characterisation of a neutron beam shaping assembly for accelerator-based BNCT. ► Measurements: total and epi-cadmium neutron fluxes and beam homogeneity. ► Calculations: Monte Carlo simulations with the MCNP code. ► Measured and calculated figure-of-merit parameters in agreement with those of IAEA. ► Initial MCNP dose calculations for a treatment room to define future design actions.
18. INEL BNCT Research Program annual report 1994
International Nuclear Information System (INIS)
This report is a summary of the progress and research produced for the Idaho National Engineering Laboratory (INEL) Boron Neutron Capture Therapy (BNCT) Research Program for calendar year 1994. Contributions from the principal investigators about their individual projects are included, specifically, chemistry (pituitary tumor studies, boron drug development including liposomes, lipoproteins, and carboranylalanine derivatives), pharmacology (murine screenings, toxicity testing, ICP-AES analysis of biological samples), physics (treatment planning software, neutron beam and filter design, neutron beam measurement dosimetry), and radiation biology (small and large animal models tissue studies and efficacy studies). Information on the potential toxicity of BSH and BPA is presented and results of 21 spontaneous tumor bearing dogs that have been treated with BNCT at Brookhaven National Laboratory (BNL) are discussed. Several boron carrying drugs exhibiting good tumor uptake are described. Significant progress in the potential of treating pituitary tumors is presented. Highlights from the First International Workshop on Accelerator-Based Neutron Sources for BNCT are included
19. PET pharmacokinetic analysis to estimate boron concentration in tumor and brain as a guide to plan BNCT for malignant cerebral glioma
Energy Technology Data Exchange (ETDEWEB)
Nariai, Tadashi [Department of Neurosurgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo (Japan)], E-mail: [email protected]; Ishiwata, Kiichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Nakacho, Itabashi-ku, Tokyo (Japan); Kimura, Yuichi [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba (Japan); Inaji, Motoki; Momose, Toshiya [Department of Neurosurgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo (Japan); Yamamoto, Tetsuya; Matsumura, Akira [Department of Neurosurgery, University of Tsukuba, Tennodai, Tsukuba, Igaraki (Japan); Ishii, Kenji [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Nakacho, Itabashi-ku, Tokyo (Japan); Ohno, Kikuo [Department of Neurosurgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo (Japan)
2009-07-15
Introduction: To plan the optimal BNCT for patients with malignant cerebral glioma, estimation of the ratio of boron concentration in tumor tissue against that in the surrounding normal brain (T/N ratio of boron) is important. We report a positron emission tomography (PET) imaging method to estimate T/N ratio of tissue boron concentration based on pharmacokinetic analysis of amino acid probes. Methods: Twelve patients with cerebral malignant glioma underwent 60 min dynamic PET scanning of brain after bolus injection of {sup 18}F-borono-phenyl-alanine (FBPA) with timed arterial blood sampling. Using kinetic parameter obtained by this scan, T/N ratio of boron concentration elicited by one-hour constant infusion of BPA, as performed in BNCT, was simulated on Runge-Kutta algorithm. {sup 11}C-methionine (MET) PET scan, which is commonly used in worldwide PET center as brain tumor imaging tool, was also performed on the same day to compare the image characteristics of FBPA and that of MET. Result: PET glioma images obtained with FBPA and MET are almost identical in all patients by visual inspection. Estimated T/N ratio of tissue boron concentration after one-hour constant infusion of BPA, T/N ratio of FBPA on static condition, and T/N ratio of MET on static condition showed significant linear correlation between each other. Conclusion: T/N ratio of boron concentration that is obtained by constant infusion of BPA during BNCT can be estimated by FBPA PET scan. This ratio can also be estimated by MET-PET imaging. As MET-PET study is available in many clinical PET center, selection of candidates for BNCT may be possible by MET-PET images. Accurate planning of BNCT may be performed by static images of FBPA PET. Use of PET imaging with amino acid probes may contribute very much to establish an appropriate application of BNCT for patients with malignant glioma.
20. Design of a beam shaping assembly and preliminary modelling of a treatment room for accelerator-based BNCT at CNEA
Energy Technology Data Exchange (ETDEWEB)
Burlon, A.A.; Girola, S. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica, San Martin (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin, San Martin (Argentina); Valda, A.A., E-mail: [email protected] [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica, San Martin (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin, San Martin (Argentina); Minsky, D.M.; Kreiner, A.J. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica, San Martin (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin, San Martin (Argentina)] [CONICET, Buenos Aires (Argentina); Sanchez, G. [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin, San Martin (Argentina)
2011-12-15
This work reports on the characterisation of a neutron beam shaping assembly (BSA) prototype and on the preliminary modelling of a treatment room for BNCT within the framework of a research programme for the development and construction of an accelerator-based BNCT irradiation facility in Buenos Aires, Argentina. The BSA prototype constructed has been characterised by means of MCNP simulations as well as a set of experimental measurements performed at the Tandar accelerator at the National Atomic Energy Commission of Argentina. - Highlights: Black-Right-Pointing-Pointer Characterisation of a neutron beam shaping assembly for accelerator-based BNCT. Black-Right-Pointing-Pointer Measurements: total and epi-cadmium neutron fluxes and beam homogeneity. Black-Right-Pointing-Pointer Calculations: Monte Carlo simulations with the MCNP code. Black-Right-Pointing-Pointer Measured and calculated figure-of-merit parameters in agreement with those of IAEA. Black-Right-Pointing-Pointer Initial MCNP dose calculations for a treatment room to define future design actions.
1. INEEL BNCT research program. Annual report, January 1, 1996--December 31, 1996
International Nuclear Information System (INIS)
This report is a summary of the progress and research produced for the Idaho National Engineering and Environmental Laboratory (INEEL) Boron Neutron Capture Therapy (BNCT) Research Program for calendar year 1996. Contributions from the individual investigators about their projects are included, specifically, physics: treatment planning software, real-time neutron beam measurement dosimetry, measurement of the Finnish research reactor epithermal neutron spectrum, BNCT accelerator technology; and chemistry: analysis of biological samples and preparation of 10B enriched decaborane
2. BNCT of canine osteosarcoma
International Nuclear Information System (INIS)
A dog was diagnosed with osteosarcoma (8x6x5cm) in the right wing of ilium by radiography, radionuclide scintigraphy and histological study of biopsy material. The treatment plan was as follows: γ-therapy in combination with chemotherapy; prevention of hematogenous pulmonary metastases by the transfusion of 130 ml of allogenic marrow from a healthy donor; administration of 11.4g 10B-boronphenylalanine into the right iliac artery; resection of the right iliac wing with the osteosarcoma lesion; neutron irradiation (MEPhI Reactor) of the bone fragment (dose on healthy osteocytes - 15±4 Gy (W), on tumor - 50±9 Gy (W); reimplantation and fixation of the fragment; three courses of adjuvant chemotherapy. The doses were determined in full-scale calculations of the reactor radiation fields with a model of the bone under the code RADUGA. The 10B concentration (μg/g) in the bone was: normal tissue - 9±3, tumor - 28±5. In 24 hours post operation the dog was able to walk using the treated limb, and 6 months later it moved freely. The patient has been under observation for 30 months. The results of the research demonstrate complete cure. The use of similar treatment plans improves the therapeutic efficiency of BNCT. (author)
3. SBNCT plan: A 3-dimensional treatment planning system for boron neutron capture therapy
International Nuclear Information System (INIS)
The need for accurate and comprehensive 3-dimensional treatment planning for boron neutron capture therapy (BNCT) has been debated for the past several years. Although many argue against the need for elaborate and expensive treatment planning programs which mimic conventional radiotherapy planning systems, it is clear that in order to realize significant gains over conventional fractionated radiation therapy, patients must be treated to the edge of normal tissue tolerance. Just how close to this edge is dictated by the uncertainties in dosimetry. Hence the focus of BNCT planning is the determination of dose distribution throughout normal tissue volumes. Although precise geometric manipulation of the epithermal neutron beam is not achievable, the following variables play an important role in BNCT optimization: patient orientation, dose fractionation, number of fields, megawatt-minutes per fraction, use of surface bolus, and use of collimation. Other variables which are not as easily adjustable and would not, therefore, be part of treatment planning optimization, include external patient contour, internal patient heterogeneities, boron compound distributions, and RBE's. The boron neutron capture therapy planning system developed at SUNY Stony Brook (SBNCT-Plan) was designed as an interactive graphic tool to assist the radiation oncologist in generating the optimum plan for a neutron capture treatment
4. Liposome and co-spray-dried PVP / o-carborane formulations for BNCT treatment of cancer
OpenAIRE
Olusanya, Temidayo; Stich, Theresia; Higgins, Samantha Caroline; Lloyd, Rhiannon Eleanor Iris; Pilkington, Geoffrey John; Fatouros, Dimitrios; Calabrese, Gianpiero; Smith, James Richard; Tsibouklis, John
2015-01-01
Purpose: Boron neutron capture therapy (BNCT) is a method for selectively destroying malignant (normally glioma) cells whilst sparing normal tissue. Irradiation of 10B (large neutron capture cross-section) with thermal neutrons effects the nuclear fission reaction: 10B + 1n → → 7Li+ + α + γ; where the penetration of α-particles and 7Li+ is only 8 and 5 µm, respectively, i.e., within a single cell thickness. Poor selectivity is the main reason why BNCT has not become a mainstream cancer therap...
5. INEEL BNCT Research Program Annual Report, CY-2000
Energy Technology Data Exchange (ETDEWEB)
Venhuizen, James Robert
2001-03-01
This report is a summary of the activities conducted in conjunction with the Idaho National Engineering and Environmental Laboratory (INEEL) Boron Neutron Capture Therapy (BNCT) Research Program for calendar year 2000. Applications of supportive research and development, as well as technology deployment in the fields of chemistry, radiation physics and dosimetry, neutron source design and demonstration, and support the Department of Energy’s (DOE) National BNCT Program goals are the goals of this Program. Contributions from the individual contributors about their projects are included, specifically described are the following, chemistry: analysis of biological samples and an infrared blood-boron analyzer, and physics: progress in the patient treatment planning software, measurement of neutron spectra for the Argentina RA-6 reactor, and recalculation of the Finnish research reactor FiR 1 neutron spectra, BNCT accelerator technology, and modification to the research reactor at Washington State University for an epithermal-neutron beam.
6. INEL BNCT Research Program annual report 1994
Energy Technology Data Exchange (ETDEWEB)
Venhuizen, J.R. [ed.
1995-11-01
This report is a summary of the progress and research produced for the Idaho National Engineering Laboratory (INEL) Boron Neutron Capture Therapy (BNCT) Research Program for calendar year 1994. Contributions from the principal investigators about their individual projects are included, specifically, chemistry (pituitary tumor studies, boron drug development including liposomes, lipoproteins, and carboranylalanine derivatives), pharmacology (murine screenings, toxicity testing, ICP-AES analysis of biological samples), physics (treatment planning software, neutron beam and filter design, neutron beam measurement dosimetry), and radiation biology (small and large animal models tissue studies and efficacy studies). Information on the potential toxicity of BSH and BPA is presented and results of 21 spontaneous tumor bearing dogs that have been treated with BNCT at Brookhaven National Laboratory (BNL) are discussed. Several boron carrying drugs exhibiting good tumor uptake are described. Significant progress in the potential of treating pituitary tumors is presented. Highlights from the First International Workshop on Accelerator-Based Neutron Sources for BNCT are included. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.
7. Depth-dose evaluation for lung and pancreas cancer treatment by BNCT using an epithermal neutron beam
International Nuclear Information System (INIS)
The depth-dose distributions were evaluated for possible treatment of both lung and pancreas cancers using an epithermal neutron beam. The MCNP calculations showed that physical dose in tumors were 6 and 7 Gy/h, respectively, for lung and pancreas, attaining an epithermal neutron flux of 5x108 ncm-2s-1. The boron concentrations were assumed at 100 ppm and 30 ppm, respectively, for lung and pancreas tumors and normal tissues contains 1/10 tumor concentrations. The dose ratios of tumor to normal tissue were 2.5 and 2.4, respectively, for lung and pancreas. The dose evaluation suggests that BNCT could be applied for both lung and pancreas cancer treatment. (author)
8. Accelerator based-boron neutron capture therapy (BNCT)-clinical QA and QC
International Nuclear Information System (INIS)
Alpha-particle and recoil Li atom yielded by the reaction (10B, n), due to their high LET properties, efficiently and specifically kill the cancer cell that has incorporated the boron. Efficacy of this boron neutron capture therapy (BNCT) has been demonstrated mainly in the treatment of recurrent head/neck and malignant brain cancers in Kyoto University Research Reactor Institute (KUR). As the clinical trial of BNCT is to start from 2009 based on an accelerator (not on the Reactor), this paper describes the tentative outline of the standard operation procedure of BNCT for its quality assurance (QA) and quality control (QC) along the flow of its clinical practice. Personnel concerned in the practice involve the attending physician, multiple physicians in charge of BNCT, medical physicists, nurses and reactor stuff. The flow order of the actual BNCT is as follows: Pre-therapeutic evaluation mainly including informed consent and confirmation of the prescription; Therapeutic planning including setting of therapy volume, and of irradiation axes followed by meeting for stuffs' agreement, decision of irradiating field in the irradiation room leading to final decision of the axis, CT for the planning, decision of the final therapeutic plan according to Japan Atomic Energy Agency-Computational Dosimetry System (JCDS) and meeting of all related personnel for the final confirmation of therapeutic plan; and BNCT including the transport of patient to KUR, dripping of boronophenylalanine, setting up of the patient on the machine, blood sampling for pharmacokinetics, boron level measurement for decision of irradiating time, switch on/off of the accelerator, confirmation of patient's movement in the irradiated field after the neutron irradiation, blood sampling for confirmation of the boron level, and patient's leave from the room. The QA/QC check is principally to be conducted with the two-person rule. The purpose of the clinical trial is to establish the usefulness of BNCT, and
9. A clinical trial protocol for second line treatment of malignant brain tumors with BNCT at University of Tsukuba
Energy Technology Data Exchange (ETDEWEB)
Aiyama, H. [Department of Neurosurgery, Graduate School of Comprehensive Human Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Nakai, K., E-mail: [email protected] [Department of Neurosurgery, Graduate School of Comprehensive Human Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Yamamoto, T. [Department of Neurosurgery, Graduate School of Comprehensive Human Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan)] [Department of Radiation Oncology, Graduate School of Comprehensive Human Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Nariai, T. [Department of Neurosurgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyouku (Japan); Kumada, H. [Department of Radiation Oncology, Graduate School of Comprehensive Human Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Ishikawa, E. [Department of Neurosurgery, Graduate School of Comprehensive Human Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Isobe, T. [Department of Radiation Oncology, Graduate School of Comprehensive Human Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Endo, K.; Takada, T.; Yoshida, F.; Shibata, Y.; Matsumura, A. [Department of Neurosurgery, Graduate School of Comprehensive Human Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan)
2011-12-15
We have evaluated the efficacy and safety of boron neutron capture therapy (BNCT) for recurrent glioma and malignant brain tumor using a new protocol. One of the two patients enrolled in this trial is a man with recurrent glioblastoma and the other is a woman with anaplastic meningioma. Both are still alive and no severe adverse events have been observed. Our findings suggest that NCT will be safe as a palliative therapy for malignant brain tumors. - Highlights: Black-Right-Pointing-Pointer Boron neutron capture therapy (BNCT) for recurrent glioma and malignant brain tumor. Black-Right-Pointing-Pointer Two cases with recurrent glioblastoma and anaplastic meningioma. Black-Right-Pointing-Pointer No severe adverse events have been observed using BNCT. Black-Right-Pointing-Pointer BNCT has a possibility of a safe palliative therapy for malignant brain tumors.
10. First clinical results on the finnish study on BPA-mediated BNCT in glioblastoma
Energy Technology Data Exchange (ETDEWEB)
Kankaanranta, L. [Helsinki University Hospital, Dept. of Oncology, Helsinki (Finland); Seppaelae, T. [University of Helsinki, Department of Physics, Helsinki (Finland); Kallio, M. [Helsinki University Hospital, Dept. of Neurology, Helsinki (Finland)] [and others
2000-10-01
An open phase I dose-escalation boron neutron capture therapy (BNCT) study on glioblastoma multiforme (GBM) was initiated at the BNCT facility FiR 1, Espoo, Finland, in May 1999. The aim of the study is to investigate the safety of boronophenylalanine (BPA)-mediated BNCT. Ten GBM patients were treated with a 2-field treatment plan using one fraction. BPA-F was used as the {sup 10}B carrier infused as a fructose solution 290 mg BPA/kg over 2-hours prior to irradiation with epithermal neutrons. Average doses to the normal brain, contrast enhancing tumour, and the target ranged from 3.0 to 5.6 Gy (W), from 35.1 to 66.7 Gy (W), and from 29.6 to 53.6 Gy (W), respectively. BNCT was associated with acceptable toxicity. The median follow-up is 9 months (range, 3 to 16 months) post diagnosis in July 2000. Seven of the 10 patients have recurrent or persistent GBM, and the median time to progression is 8 months. Only one patient has died, and the estimated 1-year overall survival is 86%. Five of the recurrent tumours were treated with external beam photon radiation therapy to the total dose of 30-40 Gy with few acute side-effects. These preliminary findings suggest that acute toxicity of BPA-mediated BNCT is acceptable when average brain doses of 5.6 Gy (W) or less are used. The followup time is too short to evaluate survival, but the estimated 1-year survival of 86% achieved with BNCT followed by conventional photon irradiation at the time of tumour progression is encouraging and emphasises the need of further investigation of BPA-mediated BNCT. (author)
11. The relationship between boron neutron capture therapy (BNCT) and positron emission tomography (PET) for malignant brain tumors
International Nuclear Information System (INIS)
Boron neutron capture therapy (BNCT) is a particle irradiation therapy that is theoretically available for selective radiation of tumor cells. Boronophenylalanine-positron emission tomography (18F-BPA-PET) was used in this study. Boron is used as a tracer compound for the neutron capture reaction and has been particularly useful for the recent noncraniotomy BNCT. In this report, we introduce this type of PET as a principal axis in BNCT and relationship with PET. We calculated the drug accumulation to the tumor before neutron irradiation to individualize the treatment. We decided the indication for BNCT on the basis of a PET study and are now expanding the indications to other systemic cancers, including head and neck, lung, and liver cancers. In addition, other irradiation modalities have developed a radiation plan on the basis of a PET study, and several studies attempted improving the results; however, the lesion is exposed to high radiation doses and appear as high accumulation on BPA-PET during BNCT. We determined the neutron exposure time from the dosage for normal tissue in the actual treatment, but the lesion/normal tissue ratio obtained from BPA-PET is for evaluating the tumor dose and following the treatment plan. We also found that a PET study was useful in the follow-up stage to aid in diagnosis of pathologic conditions such as increase in tumor volume, recurrence, or radiation necrosis and for patients who had already been treated for malignant brain tumor. (author)
12. Suitability of boron carriers for BNCT: Accumulation of boron in malignant and normal liver cells after treatment with BPA, BSH and BA
Energy Technology Data Exchange (ETDEWEB)
Chou, F.I. [Nuclear Science and Technology Development Center, National Tsing Hua University, Taiwan (China)], E-mail: [email protected]; Chung, H.P.; Liu, H.M. [Nuclear Science and Technology Development Center, National Tsing Hua University, Taiwan (China); Chi, C.W. [Department of Medical Research and Education, Taipei Veterans General Hospital, Taiwan (China); Institute of Pharmacology, School of Medicine, National Yang-Ming University, Taiwan (China); Lui, W.Y. [Department of Surgery, Taipei Veterans General Hospital, Taiwan (China); Department of Surgery, School of Medicine, National Yang-Ming University, Taiwan (China)
2009-07-15
Hepatocellular carcinoma remains widely prevalent in tropical Africa and south-east Asia. At present, there are no effective treatments for hepatoma and its prognosis is extremely poor unless the tumor was diagnosed in an early stage and resected before metastasis. Therefore, boron neutron capture therapy (BNCT) may provide an alternative therapy for treatment of hepatocellular carcinoma. In this study, the intracellular concentrations of L-boronophenylalanine (BPA), sodium borocaptate (BSH) and boric acid (BA) were examined in human hepatoma HepG2 and liver Clone 9 cell cultures. With the use of 25 {mu}g B/mL media of BPA, BSH and BA, the intracellular uptake of boron in HepG2 and Clone 9 cells was compared. The suitability of BPA, BSH and BA were further evaluated on the basis of organ-specific boron distribution in normal rat tissues. BPA, BSH and BA were administered via intraperitoneal injection into rats with corresponding boron concentrations of 7, 25, and 25 mg/kg body weight, respectively. The accumulation rates of BPA, BSH and BA in HepG2 cells were higher than that of Clone 9 cells. Boron concentration in BPA, BSH and BA treated HepG2 cells were 1.8, 1.5, and 1.6-fold of Clone 9 cells at 4 h, respectively. In both HepG2 and Clone 9 cells, although the concentration of boron in BPA-treated cells exceeded that in BA-treated ones, however, cells treated with BPA had similar surviving fraction as those treated with BA after neutron irradiation. The accumulation ratios of boron in liver, pancreas and kidney to boron in blood were 0.83, 4.16 and 2.47, respectively, in BPA treated rats, and 0.75, 0.35 and 2.89, respectively, in BSH treated rats at 3 h after treatment. However, boron does not appear to accumulate specifically in soft tissues in BA treated rats. For in situ BNCT of hepatoma, normal organs with high boron concentration and adjacent to liver may be damaged in neutron irradiation. BPA showed high retention in pancreas and may not be a good drug for
13. The BNCT project in the Czech Republic
International Nuclear Information System (INIS)
The start of clinical trials is expected before NCT Osaka 2000. The experiences from different part of project are presented. The BNCT facility at LVR-15 reactor of NRI consists of epithermal neutron beam with improved construction (6.98 x 108/cm2s with acceptable background of fast neutrons and gammas) and irradiation and control rooms equipped by appropriate devices. Internationally-recognized software MacNCTPLAN is utilized for computational dosimetry and treatment planning. In the part of protocol the following parameters have been assessed: patient selection, BSH dosage, fractionation, starting dose, dose escalation steps. At the LVR-15, at horizontal channel, a prompt gamma ray analysis (PGRA) system has been developed and is operated for BNCT purposes. Some human blood samples were analyzed and compared with classical ICP method. During the process of licensing the experience was obtained, some notes are discussed in the paper. The first results were received for the study of biological effect of the LVR source for small animal model. (author)
14. Measurement and simulation of the TRR BNCT beam parameters
Science.gov (United States)
2016-09-01
Recently, the configuration of the Tehran Research Reactor (TRR) thermal column has been modified and a proper thermal neutron beam for preclinical Boron Neutron Capture Therapy (BNCT) has been obtained. In this study, simulations and experimental measurements have been carried out to identify the BNCT beam parameters including the beam uniformity, the distribution of the thermal neutron dose, boron dose, gamma dose in a phantom and also the Therapeutic Gain (TG). To do this, the entire TRR structure including the reactor core, pool, the thermal column and beam tubes have been modeled using MCNPX Monte Carlo code. To measure in-phantom dose distribution a special head phantom has been constructed and foil activation techniques and TLD700 dosimeter have been used. The results show that there is enough uniformity in TRR thermal BNCT beam. TG parameter has the maximum value of 5.7 at the depth of 1 cm from the surface of the phantom, confirming that TRR thermal neutron beam has potential for being used in treatment of superficial brain tumors. For the purpose of a clinical trial, more modifications need to be done at the reactor, as, for example design, and construction of a treatment room at the beam exit which is our plan for future. To date, this beam is usable for biological studies and animal trials. There is a relatively good agreement between simulation and measurement especially within a diameter of 10 cm which is the dimension of usual BNCT beam ports. This relatively good agreement enables a more precise prediction of the irradiation conditions needed for future experiments.
15. INEL BNCT research program: Annual report, 1995
International Nuclear Information System (INIS)
This report is a summary of the progress and research produced for the Idaho National Engineering Laboratory (INEL) Boron Neutron Capture Therapy (BNCT) Research Program for calendar year 1995. Contributions from the principal investigators about their individual projects are included, specifically, physics (treatment planning software, real-time neutron beam measurement dosimetry), and radiation biology (large animal models efficacy studies). Design of a reactor based epithermal neutron extraction facility is discussed in detail. Final results of boron magnetic resonance imagining is included for both borocaptate sodium (BSH) and boronophenylalanine (BPA) in rats, and BSH in humans. Design of an epithermal neutron facility using electron linear accelerators is presented, including a treatise on energy removal from the beam target. Information on the multiple fraction injection of BSH in rats is presented
16. INEL BNCT research program: Annual report, 1995
Energy Technology Data Exchange (ETDEWEB)
Venhuizen, J.R. [ed.
1996-04-01
This report is a summary of the progress and research produced for the Idaho National Engineering Laboratory (INEL) Boron Neutron Capture Therapy (BNCT) Research Program for calendar year 1995. Contributions from the principal investigators about their individual projects are included, specifically, physics (treatment planning software, real-time neutron beam measurement dosimetry), and radiation biology (large animal models efficacy studies). Design of a reactor based epithermal neutron extraction facility is discussed in detail. Final results of boron magnetic resonance imagining is included for both borocaptate sodium (BSH) and boronophenylalanine (BPA) in rats, and BSH in humans. Design of an epithermal neutron facility using electron linear accelerators is presented, including a treatise on energy removal from the beam target. Information on the multiple fraction injection of BSH in rats is presented.
17. Might iodomethyl-α-tyrosine be a surrogate for BPA in BNCT?
International Nuclear Information System (INIS)
A single-photon emission computed tomography [SPECT] imaging agent that is an analogue of a boron carrier for boron neutron-capture therapy [BNCT] of cerebral gliomas would be useful for assessing the kinetics of boron uptake in tumors and in the surrounding brain tissues noninvasively. BNCT is based on the interaction of thermalized neutrons with 10B nuclei in the targeted tumor. For BNCT of brain tumors, it is crucial that 10B concentrations in radiosensitive regions of the brain be minimal since malignant cells and vital brain tissues are often inter-mingled at the margins of the tumor. Currently, boronophenylalanine [BPA]-mediated BNCT is undergoing preliminary clinical study for postoperative radiotherapy of glioblastorna multiforme at Brookhaven National Laboratory. Investigators in Japan are developing 18F-fluoroboronophenylaianine [FBPA] as a positron 18F (T1/2 = 110 min), which is usually emission tomography [PET] surrogate for BPA. generated at a cyclotron dedicated to PET, is generally a minimally perturbing substitute for the 2-H on the aromatic ring because of its small size and the strong covalent bond it forms with carbon. However, SPECT has potential advantages over PET: (1) SPECT is clinically more widely available at lower cost; (2) most radioisotopes for the synthesis of SPECT agents can be purchased; (3) SPECT is less difficult to implement. It is thought that the quality of images derived from the two techniques would each be sufficiently informative for BNCT treatment planning purposes, provided that the SPECT and PET agents being considered were both pharmacokinetic surrogates for BPA. This study evaluated the use of 123I alpha methyltyrosine as a surrogate for BPA in BNCT
18. Might iodomethyl-{alpha}-tyrosine be a surrogate for BPA in BNCT?
Energy Technology Data Exchange (ETDEWEB)
Miura, Michiko; Micca, P.L.; Nawrocky, M.M.; Slatkin, D.N.
1996-12-31
A single-photon emission computed tomography [SPECT] imaging agent that is an analogue of a boron carrier for boron neutron-capture therapy [BNCT] of cerebral gliomas would be useful for assessing the kinetics of boron uptake in tumors and in the surrounding brain tissues noninvasively. BNCT is based on the interaction of thermalized neutrons with {sup 10}B nuclei in the targeted tumor. For BNCT of brain tumors, it is crucial that {sup 10}B concentrations in radiosensitive regions of the brain be minimal since malignant cells and vital brain tissues are often inter-mingled at the margins of the tumor. Currently, boronophenylalanine [BPA]-mediated BNCT is undergoing preliminary clinical study for postoperative radiotherapy of glioblastorna multiforme at Brookhaven National Laboratory. Investigators in Japan are developing {sup 18}F-fluoroboronophenylaianine [FBPA] as a positron {sup 18}F (T{sub 1/2} = 110 min), which is usually emission tomography [PET] surrogate for BPA. generated at a cyclotron dedicated to PET, is generally a minimally perturbing substitute for the 2-H on the aromatic ring because of its small size and the strong covalent bond it forms with carbon. However, SPECT has potential advantages over PET: (1) SPECT is clinically more widely available at lower cost; (2) most radioisotopes for the synthesis of SPECT agents can be purchased; (3) SPECT is less difficult to implement. It is thought that the quality of images derived from the two techniques would each be sufficiently informative for BNCT treatment planning purposes, provided that the SPECT and PET agents being considered were both pharmacokinetic surrogates for BPA. This study evaluated the use of {sup 123}I alpha methyltyrosine as a surrogate for BPA in BNCT.
19. Neutron-photon mixed field dosimetry by TLD-700 glow curve analysis and its implementation in dose monitoring for Boron Neutron Capture Therapy (BNCT) treatments
International Nuclear Information System (INIS)
BNCT is a cancerous cells selective, non-conventional radiotherapy modality to treat malignant tumors such as glioblastoma, melanoma and recurrent head and neck cancer. It consists of a two-step procedure: first, the patient is injected with a tumor localizing drug containing a non-radioactive isotope (Boron-10) with high slow neutron capture cross-section. In a second step, the patient is irradiated with neutrons, which are absorbed by the Boron-10 agent with the subsequently nuclear reaction B- 10(n,a)Li-7, thereby resulting in dose at cellular level due to the high-Let particles. The neutron fields suitable for BNCT are characterized by high neutron fluxes and low gamma dose. Determination of each component is not an easy task, especially when the volume of measurement is quite small or inaccessible for a miniature ionization chamber, for example. A method of measuring the photon and slow neutron dose(mainly by N-14 and B-10) from the glow curve (GC) analysis of a single 7LiF thermoluminescence detector is evaluated. This method was suggested by the group headed by Dr. Grazia Gambarini. The dosemeters used were TLD-600 (6LiF:Mg,Ti with 95.6% 6Li) and TLD-700 (7LiF:Mg,Ti with 99.9% 7LiF) from Harshaw. Photon dose measurement using the GC analysis method with TLD-700 in mixed fields requires the relation of the two main peaks of a TLD-600 GC shape obtained from an exposition to the same neutron field, and a photon calibrated GC with TLD-700. The requirements for slow neutron dose measurements are similar. In order to properly apply the GC analysis method at the Ra-6 Research Reactor BNCT facility, measurements were carried out in a standard water phantom, fully characterized on the BNCT beam by conventional techniques (activation detectors and paired ionization chambers technique). Next, the method was implemented in whole body dose monitoring of a patient undergoing a BNCT treatment, using a Bo MAb (Bottle Manikin Absorption) phantom, with representative
20. Neutron-photon mixed field dosimetry by TLD-700 glow curve analysis and its implementation in dose monitoring for Boron Neutron Capture Therapy (BNCT) treatments
Energy Technology Data Exchange (ETDEWEB)
Boggio, E. F.; Longhino, J. M. [Centro Atomico Bariloche, Departamento de Fisica de Reactores y Radiaciones / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina); Andres, P. A., E-mail: [email protected] [Centro Atomico Bariloche, Division Proteccion Radiologica / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina)
2015-10-15
BNCT is a cancerous cells selective, non-conventional radiotherapy modality to treat malignant tumors such as glioblastoma, melanoma and recurrent head and neck cancer. It consists of a two-step procedure: first, the patient is injected with a tumor localizing drug containing a non-radioactive isotope (Boron-10) with high slow neutron capture cross-section. In a second step, the patient is irradiated with neutrons, which are absorbed by the Boron-10 agent with the subsequently nuclear reaction B- 10(n,a)Li-7, thereby resulting in dose at cellular level due to the high-Let particles. The neutron fields suitable for BNCT are characterized by high neutron fluxes and low gamma dose. Determination of each component is not an easy task, especially when the volume of measurement is quite small or inaccessible for a miniature ionization chamber, for example. A method of measuring the photon and slow neutron dose(mainly by N-14 and B-10) from the glow curve (GC) analysis of a single {sup 7}LiF thermoluminescence detector is evaluated. This method was suggested by the group headed by Dr. Grazia Gambarini. The dosemeters used were TLD-600 ({sup 6}LiF:Mg,Ti with 95.6% {sup 6}Li) and TLD-700 ({sup 7}LiF:Mg,Ti with 99.9% {sup 7}LiF) from Harshaw. Photon dose measurement using the GC analysis method with TLD-700 in mixed fields requires the relation of the two main peaks of a TLD-600 GC shape obtained from an exposition to the same neutron field, and a photon calibrated GC with TLD-700. The requirements for slow neutron dose measurements are similar. In order to properly apply the GC analysis method at the Ra-6 Research Reactor BNCT facility, measurements were carried out in a standard water phantom, fully characterized on the BNCT beam by conventional techniques (activation detectors and paired ionization chambers technique). Next, the method was implemented in whole body dose monitoring of a patient undergoing a BNCT treatment, using a Bo MAb (Bottle Manikin Absorption) phantom
1. Feasibility of boron neutron capture therapy (BNCT) for malignant pleural mesothelioma from a viewpoint of dose distribution analysis
International Nuclear Information System (INIS)
Purpose: To investigate the feasibility of boron neutron capture therapy (BNCT) for malignant pleural mesothelioma (MPM) from a viewpoint of dose distribution analysis using Simulation Environment for Radiotherapy Applications (SERA), a currently available BNCT treatment planning system. Methods and Materials: The BNCT treatment plans were constructed for 3 patients with MPM using the SERA system, with 2 opposed anterior-posterior beams. The 1B concentrations in the tumor and normal lung in this study were assumed to be 84 and 24 ppm, respectively, and were derived from data observed in clinical trials. The maximum, mean, and minimum doses to the tumors and the normal lung were assessed for each plan. The doses delivered to 5% and 95% of the tumor volume, D05 and D95, were adopted as the representative dose for the maximum and minimum dose, respectively. Results: When the D05 to the normal ipsilateral lung was 5 Gy-Eq, the D95 and mean doses delivered to the normal lung were 2.2-3.6 and 3.5-4.2 Gy-Eq, respectively. The mean doses delivered to the tumors were 22.4-27.2 Gy-Eq. The D05 and D95 doses to the tumors were 9.6-15.0 and 31.5-39.5 Gy-Eq, respectively. Conclusions: From a viewpoint of the dose-distribution analysis, BNCT has the possibility to be a promising treatment for MPM patients who are inoperable because of age and other medical illnesses
2. The studsvik BNCT project: structure and the proposed protocols
International Nuclear Information System (INIS)
The BNCT facility at Studsvik is now ready for clinical trials. Scientific operations of the Studsvik BNCT project are overseen by the Scientific Advisory Board comprised of representatives of all major universities in Sweden. Furthermore, special task groups for clinical and preclinical studies have been formed to facilitate collaboration with academia and to assure the quality of the research. Proposed clinical Phase II trials for glioblastoma are sponsored by the Swedish National Neuro-Oncology Group and, initially, will involve two protocols: Protocol no.1. BNCT for glioblastoma patients who have not received any therapy other than surgery (including stereotactic biopsy only). Protocol no.2. BNCT as a palliative treatment for patients with recurrent glioblastoma following conventional therapies or BNCT. In both protocols, BPA, administered by a 6 hour i.v. infusion, will be used as the boron delivery agent. (author)
3. BNCT Technology Development on HANARO Reactor
International Nuclear Information System (INIS)
So as to establish the biological effects of BNCT in the HANARO Reactor, biological damages in cells and animals with treatment of boron/neutron were investigated. And 124I-BPA animal PET image, analysis technology of the boron contents in the mouse tissues by ICP-AES was established. A Standard clinical protocol, a toxicity evaluation report and an efficacy investigation report of BNCT has been developed. Based on these data, the primary permission of clinical application was acquired through IRB of our hospital. Three cases of pre-clinical experiment for boron distribution and two cases of medium-sized animal simulation experiment using cat with verifying for 2 months after BNCT was performed and so the clinical demonstration with a patient was prepared. Also neutron flux, fast neutron flux and gamma ray dose of BNCT facility were calculated and these data will be utilized good informations for clinical trials and further BNCT research. For the new synthesis of a boron compound, o-carboranyl ethylamine, o-carboranylenepiperidine, o-carboranyl-THIQ and o-carboranyl-s-triazine derivatives were synthesized. Among them, boron uptake in the cancer cell of the triazine derivative was about 25 times than that of BPA and so these three synthesized methods of new boron compounds were patented
4. BNCT Technology Development on HANARO Reactor
Energy Technology Data Exchange (ETDEWEB)
Chun, Ki Jung; Park, Kyung Bae; Whang, Seung Ryul; Kim, Myong Seop
2007-06-15
So as to establish the biological effects of BNCT in the HANARO Reactor, biological damages in cells and animals with treatment of boron/neutron were investigated. And 124I-BPA animal PET image, analysis technology of the boron contents in the mouse tissues by ICP-AES was established. A Standard clinical protocol, a toxicity evaluation report and an efficacy investigation report of BNCT has been developed. Based on these data, the primary permission of clinical application was acquired through IRB of our hospital. Three cases of pre-clinical experiment for boron distribution and two cases of medium-sized animal simulation experiment using cat with verifying for 2 months after BNCT was performed and so the clinical demonstration with a patient was prepared. Also neutron flux, fast neutron flux and gamma ray dose of BNCT facility were calculated and these data will be utilized good informations for clinical trials and further BNCT research. For the new synthesis of a boron compound, o-carboranyl ethylamine, o-carboranylenepiperidine, o-carboranyl-THIQ and o-carboranyl-s-triazine derivatives were synthesized. Among them, boron uptake in the cancer cell of the triazine derivative was about 25 times than that of BPA and so these three synthesized methods of new boron compounds were patented.
5. Radiation Dosimetry in the BNCT Patient Treatment Room at the Brookhaven Medical Research Reactor
International Nuclear Information System (INIS)
The BMRR was a 3 MW light water reactor that had an epithermal neutron beam that was used to perform clinical trials on patients with malignant brain tumors. A series of measurements and calculations had been performed in the treatment room both prior to the trials and during the trials. The details of the measurements and the Monte Carlo calculations are presented and compared.
6. BNCT. Computational Analysis; BNCT. Analisis computacional
Energy Technology Data Exchange (ETDEWEB)
Caro, R.
2004-07-01
The BNCT (Boron Neutron Capture Therapy) is a new oncologic radiotherapy technique in the process of research which consists of injecting a non-poisonous pharmacovector into an ill patient in such a way that the tumor receives isotope boron-10, so that the tumoral area can later be bombarded with a beam of neutrons, many of which are captured the isotope in question. (Author)
7. Production of epithermal neutron beams for BNCT
CERN Document Server
Bisceglie, E; Colonna, N; Paticchio, V; Santorelli, P; Variale, V
2002-01-01
The use of boron neutron capture therapy (BNCT) for the treatment of deep-seated tumors requires neutron beams of suitable energy and intensity. Simulations indicate the optimal energy to reside in the epithermal region, in particular between 1 and 10 keV. Therapeutic neutron beams with high spectral purity in this energy range could be produced with accelerator-based neutron sources through a suitable neutron-producing reaction. Herein, we report on different solutions that have been investigated as possible sources of epithermal neutron beams for BNCT. The potential use of such sources for a hospital-based therapeutic facility is discussed.
8. Experimental Studies of Boronophenylalanine ({sup 10}BPA) Biodistribution for the Individual Application of Boron Neutron Capture Therapy (BNCT) for Malignant Melanoma Treatment
Energy Technology Data Exchange (ETDEWEB)
Carpano, Marina; Perona, Marina; Rodriguez, Carla [Department of Radiobiology, National Atomic Energy Commission, San Martín (Argentina); Nievas, Susana; Olivera, Maria; Santa Cruz, Gustavo A. [Department of Boron Neutron Capture Therapy, National Atomic Energy Commission, San Martín (Argentina); Brandizzi, Daniel; Cabrini, Romulo [Department of Radiobiology, National Atomic Energy Commission, San Martín (Argentina); School of Dentistry, University of Buenos Aires, Buenos Aires (Argentina); Pisarev, Mario [Department of Radiobiology, National Atomic Energy Commission, San Martín (Argentina); National Research Council of Argentina, Buenos Aires (Argentina); Department of Human Biochemistry, School of Medicine, University of Buenos Aires, Buenos Aires (Argentina); Juvenal, Guillermo Juan [Department of Radiobiology, National Atomic Energy Commission, San Martín (Argentina); National Research Council of Argentina, Buenos Aires (Argentina); Dagrosa, Maria Alejandra, E-mail: [email protected] [Department of Radiobiology, National Atomic Energy Commission, San Martín (Argentina); National Research Council of Argentina, Buenos Aires (Argentina)
2015-10-01
Purpose: Patients with the same histopathologic diagnosis of cutaneous melanoma treated with identical protocols of boron neutron capture therapy (BNCT) have shown different clinical outcomes. The objective of the present studies was to evaluate the biodistribution of boronophenilalanina ({sup 10}BPA) for the potential application of BNCT for the treatment of melanoma on an individual basis. Methods and Materials: The boronophenilalanine (BPA) uptake was evaluated in 3 human melanoma cell lines: MEL-J, A375, and M8. NIH nude mice were implanted with 4 10{sup 6} MEL-J cells, and biodistribution studies of BPA (350 mg/kg intraperitoneally) were performed. Static infrared imaging using a specially modified infrared camera adapted to measure the body infrared radiance of small animals was used. Proliferation marker, Ki-67, and endothelial marker, CD31, were analyzed in tumor samples. Results: The in vitro studies demonstrated different patterns of BPA uptake for each analyzed cell line (P<.001 for MEL-J and A375 vs M8 cells). The in vivo studies showed a maximum average boron concentration of 25.9 ± 2.6 μg/g in tumor, with individual values ranging between 11.7 and 52.0 μg/g of {sup 10}B 2 hours after the injection of BPA. Tumor temperature always decreased as the tumors increased in size, with values ranging between 37°C and 23°C. A significant correlation between tumor temperature and tumor-to-blood boron concentration ratio was found (R{sup 2} = 0.7, rational function fit). The immunohistochemical studies revealed, in tumors with extensive areas of viability, a high number of positive cells for Ki-67, blood vessels of large diameter evidenced by the marker CD31, and a direct logistic correlation between proliferative status and boron concentration difference between tumor and blood (R{sup 2} = 0.81, logistic function fit). Conclusion: We propose that these methods could be suitable for designing new screening protocols applied before melanoma BNCT
9. Experimental Studies of Boronophenylalanine (10BPA) Biodistribution for the Individual Application of Boron Neutron Capture Therapy (BNCT) for Malignant Melanoma Treatment
International Nuclear Information System (INIS)
Purpose: Patients with the same histopathologic diagnosis of cutaneous melanoma treated with identical protocols of boron neutron capture therapy (BNCT) have shown different clinical outcomes. The objective of the present studies was to evaluate the biodistribution of boronophenilalanina (10BPA) for the potential application of BNCT for the treatment of melanoma on an individual basis. Methods and Materials: The boronophenilalanine (BPA) uptake was evaluated in 3 human melanoma cell lines: MEL-J, A375, and M8. NIH nude mice were implanted with 4 106 MEL-J cells, and biodistribution studies of BPA (350 mg/kg intraperitoneally) were performed. Static infrared imaging using a specially modified infrared camera adapted to measure the body infrared radiance of small animals was used. Proliferation marker, Ki-67, and endothelial marker, CD31, were analyzed in tumor samples. Results: The in vitro studies demonstrated different patterns of BPA uptake for each analyzed cell line (P<.001 for MEL-J and A375 vs M8 cells). The in vivo studies showed a maximum average boron concentration of 25.9 ± 2.6 μg/g in tumor, with individual values ranging between 11.7 and 52.0 μg/g of 10B 2 hours after the injection of BPA. Tumor temperature always decreased as the tumors increased in size, with values ranging between 37°C and 23°C. A significant correlation between tumor temperature and tumor-to-blood boron concentration ratio was found (R2 = 0.7, rational function fit). The immunohistochemical studies revealed, in tumors with extensive areas of viability, a high number of positive cells for Ki-67, blood vessels of large diameter evidenced by the marker CD31, and a direct logistic correlation between proliferative status and boron concentration difference between tumor and blood (R2 = 0.81, logistic function fit). Conclusion: We propose that these methods could be suitable for designing new screening protocols applied before melanoma BNCT treatment for each individual
10. INEL BNCT Program
Energy Technology Data Exchange (ETDEWEB)
Ackermann, A.L. (ed.)
1991-08-01
This Bulletin presents a summary of accomplishments and highlights in the Idaho National Engineering Laboratory's (INEL) Boron Neutron Capture Therapy (BNCT) Program for August 1991. This bulletin includes information on the brain tumor and melanoma research programs, Power Burst Facility (PBF) technical support and modifications, PBF operations, and updates to the animal data charts.
11. New EORTC clinical trials for BNCT
International Nuclear Information System (INIS)
Due to ethical reasons, a separated optimization of the two components of BNCT in the frame of clinical investigations can only be performed applying the whole binary system. The ongoing trial at HFR (High Flux Reactor Petten) has proven the feasibility of BNCT under defined conditions. On that basis the European Commission supported a comprehensive research project on boron imaging including three further clinical studies. In the first trial the boron uptake related to the blood boron concentration and surrounding normal tissue in various solid tumours will be examined using BSH (Sodiumborocaptate), BPA (Boronophenylalanine) or both in order to explore tumour entities, which may gain benefit from BNCT. The major objectives of the second trial are to define the maximum tolerated single and cumulative dose, and the dose limiting toxicity of BSH. The third clinical trial, a phase II study is designed to evaluate the anti-tumour effect of fractionated BNCT at the Petten treatment facility against cerebral metastasis of malignant melanoma using BPA. (author)
12. BNCT and dose fractionation
International Nuclear Information System (INIS)
Some portion of the radiation dose received by a patient during BNCT consists of primary and secondary gammas. The biological effect of that portion of the dose will depend upon the time history of the delivered dose. The well-known models for relating time-dose effects to clinical experience, are of questionable value in understanding dose effects in the time regime of a few hours, and for doses of less than tolerance. In order to examine the time-dose effect in the regime of interest to BNCT a simple phenomenological model was developed and normalized to the accepted body of clinical experience. The model has been applied to the question of fractionation of BNCT and the results are presented. The model is simply a linear healing model with two time constants. In other words, a first hit of radiation is assumed to wound (or potentiate) a cell. Given time, the cell will fully repair itself. If a second hit occurs before the cell has healed, the cell is killed. Apparently, there are two kinds of healing, one which occurs in 30 to 60 minutes, the other in two to four days. A small fraction of the cells will die on the first hit
13. In-phantom dosimetry for BNCT with Fricke and normoxic-polymer gels
Science.gov (United States)
Gambarini, G.; Agosteo, S.; Carrara, M.; Gay, S.; Mariani, M.; Pirola, L.; Vanossi, E.
2006-05-01
Measurements of in-phantom dose distributions and images are important for Boron Neutron Capture Therapy treatment planning. The method for spatial determination of absorbed doses in thermal or epithermal neutron fields, based on Fricke-xylenol-orange-infused gel dosimeters in form of layers, has revealed to be very reliable, as gel layer dosimeters give the possibility of obtaining spatial dose distributions and measurements of each dose contribution in neutron fields, by means of a properly studied procedure. Quite recently, BNCT has been applied to treat liver metastases; in this work the results of in-phantom dosimetry for explanted liver in BNCT treatments are described. Moreover, polyacrylamide gel (PAG) dosimeters in which a polymerization process appears as a consequence of absorbed dose, have been recently tested, because of their characteristic absence of diffusion. In fact, due to the diffusion of ferric ions, Fricke-gel dosimeters require prompt analysis after exposure to avoid spatial information loss. In this work the preliminary results of a study about the reliability of polymer gel in BNCT dosimetry are also discussed. Gel layers have been irradiated in a phantom exposed in the thermal column of the TRIGA MARK II reactor (Pavia). The results obtained with the two kinds of gel dosimeter have been compared.
14. An Accelerator Neutron Source for BNCT
Energy Technology Data Exchange (ETDEWEB)
Blue, Thomas, E
2006-03-14
The overall goal of this project was to develop an accelerator-based neutron source (ABNS) for Boron Neutron Capture Therapy (BNCT). Specifically, our goals were to design, and confirm by measurement, a target assembly and a moderator assembly that would fulfill the design requirements of the ABNS. These design requirements were 1) that the neutron field quality be as good as the neutron field quality for the reactor-based neutron sources for BNCT, 2) that the patient treatment time be reasonable, 3) that the proton current required to treat patients in reasonable times be technologially achievable at reasonable cost with good reliability, and accelerator space requirements which can be met in a hospital, and finally 4) that the treatment be safe for the patients.
15. An Accelerator Neutron Source for BNCT
International Nuclear Information System (INIS)
The overall goal of this project was to develop an accelerator-based neutron source (ABNS) for Boron Neutron Capture Therapy (BNCT). Specifically, our goals were to design, and confirm by measurement, a target assembly and a moderator assembly that would fulfill the design requirements of the ABNS. These design requirements were (1) that the neutron field quality be as good as the neutron field quality for the reactor-based neutron sources for BNCT, (2) that the patient treatment time be reasonable, (3) that the proton current required to treat patients in reasonable times be technologically achievable at reasonable cost with good reliability, and accelerator space requirements which can be met in a hospital, and finally (4) that the treatment be safe for the patients
16. A new NEDO research project towards hospital based accelerator BNCT using advanced DDS system
International Nuclear Information System (INIS)
A new national project of developing a hospital based accelerator for boron neutron capture therapy (BNCT) with advanced drug delivery system (DDS) has been started in 2005. In this paper, the outline of the new project will be introduced. The project includes two main topics: 1) a hospital based accelerator for BNCT will be developed by a research consortium of Universities and companies. A fixed field alternating gradient (FFAG) type of accelerator with internal target is planned. 2) New boronated DDS using different methods including porphyrins, virus envelope vector, and liposome are planned. BNCT may become a first line charged particle therapy if the hospital based accelerator become feasible due to broadening the opportunity to use the neutron source. Due to such clinical convenience, there will be also possibility to spread the indication of BNCT for the diseases (cancer and other diseases) which has not been the candidate for BNCT in the nuclear-reactor era. (author)
17. Treatment planning systems
International Nuclear Information System (INIS)
All aspects of treatment planning in radiotherapy are discussed in detail. Included are, among others, machine data and their acquisition, photon dose calculations and tests thereof, criteria of acceptability, sources of uncertainties, from 2D to 3D and from 3D to IMRT, dosimetric measurements for RTP validation, frequency of QA tests and suggested tolerances for TPS, time and staff requirements, model based segmentation, multi-dimensional radiotherapy (MDCRT), and biological IMRT process. (P.A.)
18. Treatment Planning for Accelerator-Based Boron Neutron Capture Therapy
Science.gov (United States)
Herrera, María S.; González, Sara J.; Minsky, Daniel M.; Kreiner, Andrés J.
2010-08-01
Glioblastoma multiforme and metastatic melanoma are frequent brain tumors in adults and presently still incurable diseases. Boron Neutron Capture Therapy (BNCT) is a promising alternative for this kind of pathologies. Accelerators have been proposed for BNCT as a way to circumvent the problem of siting reactors in hospitals and for their relative simplicity and lower cost among other advantages. Considerable effort is going into the development of accelerator-based BNCT neutron sources in Argentina. Epithermal neutron beams will be produced through appropriate proton-induced nuclear reactions and optimized beam shaping assemblies. Using these sources, computational dose distributions were evaluated in a real patient with diagnosed glioblastoma treated with BNCT. The simulated irradiation was delivered in order to optimize dose to the tumors within the normal tissue constraints. Using Monte Carlo radiation transport calculations, dose distributions were generated for brain, skin and tumor. Also, the dosimetry was studied by computing cumulative dose-volume histograms for volumes of interest. The results suggest acceptable skin average dose and a significant dose delivered to tumor with low average whole brain dose for irradiation times less than 60 minutes, indicating a good performance of an accelerator-based BNCT treatment.
19. BNCT irradiation facility at the JRR-4
Energy Technology Data Exchange (ETDEWEB)
Torii, Y.; Kishi, T.; Kumada, H.; Yamamoto, K.; Sakurai, F.; Takayanagi, M. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
2000-10-01
The JRR--4 was modified for fuel enrichment reducing and reactor equipment renewal. And also a medical irradiation facility for the Boron Neutron Capture Therapy (BNCT) was installed at the JRR--4 in that time. The medical irradiation facility has been composed of a heavy water tank, a collimator and an irradiation room. The heavy water tank has four layers of heavy water for spectrum shifter and 75cm-thickness aluminum for the shield of fast neutron. The collimator is for collimating thermal neutron and epithermal neutron using polyethylene with lithium-fluoride and shielding gamma ray by bismuth. The irradiation room has sufficient space at exit side of the beam, to accommodate a large working area for setting the patient. Both of the medical treatment room and the patient-monitoring area were prepared adjacent to the irradiation room. The medical irradiation facility in the JRR-4 is designed to permit selection of neutron energies from thermal neutron to epithermal neutron by changing the thickness of heavy water layers. Therefore it is available to continue the same kind of BNCT with thermal neutron used to perform in the JRR-2, as well as to commence the research and development of BNCT with epithermal neutron, which will make the brain tumor treatment possible at a deep part of brain. The full power operation of the JRR-4 was resumed with LEU fuel in October 1998 and currently performing some experiments to measure the neutron fluxes and physical doses for determinate characterization of the medical irradiation facility. The first medical irradiation for BNCT was carried out on 25th October 1999. The patient was treated by Tsukuba University group using thermal neutron beam included epi-thermal neutrons. (author)
20. Integral multidisciplinary rehabilitation treatment planning
NARCIS (Netherlands)
Braaksma, A.; Kortbeek, Nikky; Post, Gerhard; Nollet, Frans
2012-01-01
This paper presents a methodology to plan treatments for rehabilitation outpatients. These patients require a series of treatments by therapists from various disciplines. In current practice, when treatments are planned, a lack of coordination between the different disciplines, along with a failure
1. Integral multidisciplinary rehabilitation treatment planning
NARCIS (Netherlands)
Braaksma, A.; Kortbeek, N.; Post, G.F.; Nollet, F.
2014-01-01
This paper presents a methodology to plan treatments for rehabilitation outpatients. These patients require a series of treatments by therapists from various disciplines. In current practice, when treatments are planned, a lack of coordination between the different disciplines, along with a failure
2. Preliminary Design of LEU MNSR for BNCT with Excellent Epithermal Neutron Flux Treatment Beam%高额超热中子束流治疗孔道低浓化BNCT堆初步设计方案
Institute of Scientific and Technical Information of China (English)
于涛; 钱金栋; 谢金森
2012-01-01
Based on the Miniature Neutron Source Reactor (MNSR) with high enrichment uranium (HEU) fuel and accordance with the requirements of BNCT, the 19.5% of enriched fuel UO2 fuel core for BNCT with epithermal neutron treatment beam was primary designed, the reactor core parameters such as epithermal neutron flux density,epithermal neutron flux unit of fast neutron dose rate,epithermal neutron flux unit photon dose rate of γ,epithermal neutron flux ratio of thermal neutron flux, neutron spectrum were calculated and analyzed. The results show that the design program was an excellent epithermal neutron treatment beam.%根据硼中子俘获治疗( BNCT)中子源的要求,在高浓铀为燃料的微型反应堆(MNSR)的基础上,以富集度19.5％的UO2为燃料,将其堆芯低浓化并且添加水平超热中子束流治疗孔道,开展超热中子束流BNCT堆堆芯低浓化初步设计.计算BNCT堆的超热中子注量率、单位超热中子注量的快中子剂量率、单位超热中子注量的γ光子剂量率、超热中子注量与热中子的注量之比、中子束流能谱等关键参数.结果表明,该设计可以得到优良的超热中子束流.
3. Boron neutron capture therapy (BNCT) for glioblastoma multiforme using the epithermal neutron beam at the Brookhaven Medical Research Reactor
Energy Technology Data Exchange (ETDEWEB)
Capala, J. [Brookhaven National Lab., Upton, NY (United States); Diaz, A.Z.; Chadha, M. [Univ. Hospital, State Univ. of New York, NY (United States)] [and others
1997-12-31
The abstract describes evaluation of boron neutron capture therapy (BNCT) for two groups of glioblastoma multiforme patients. From September 1994 to February 1996 15 patients have been treated. In September 1997 another 34 patients were examined. Authors determined a safe starting dose for BNCT using epithermal neutrons and BPA-F. They have also evaluated adverse effects of BNCT at this starting dose. Therapeutic effectiveness of this starting dose has been evaluated. No significant side effects from BPA-F infusion or BNCT treatment were observed in normal brains.
4. Extra-corporeal liver BNCT for the treatment of diffuse metastases: What was learned and what is still to be learned
Energy Technology Data Exchange (ETDEWEB)
Zonta, A. [Department of Surgery, University of Pavia, Pavia (Italy)], E-mail: [email protected]; Pinelli, T. [Department of Nuclear and Theoretical Physics, University of Pavia, Pavia (Italy); National Institute of Nuclear Physics (INFN) Pavia Section, Pavia (Italy); Prati, U.; Roveda, L. [Oncologic Surgery, Cancer Center of Excellence Fond. ' T. Campanella' , Catanzaro (Italy); Ferrari, C.; Clerici, A.M.; Zonta, C. [Department of Surgery, University of Pavia, Pavia (Italy); Mazzini, G. [Department of Animal Biol., IGM-CNR Histochemistry and Cytometry Section, Pavia (Italy); Dionigi, P. [Department of Surgery, University of Pavia, Pavia (Italy); Altieri, S.; Bortolussi, S. [Department of Nuclear and Theoretical Physics, University of Pavia, Pavia (Italy); National Institute of Nuclear Physics (INFN) Pavia Section, Pavia (Italy); Bruschi, P. [Department of Nuclear and Theoretical Physics, University of Pavia, Pavia (Italy); Fossati, F. [Department of Nuclear and Theoretical Physics, University of Pavia, Pavia (Italy); National Institute of Nuclear Physics (INFN) Pavia Section, Pavia (Italy)
2009-07-15
Almost eight years ago, in December 2001, we performed for the first time in the world thermal neutron irradiation on an isolated liver of a patient. The organ was affected by diffuse metastases of a colon carcinoma and had been previously loaded with a {sup 10}B compound. In July 2003, the same procedure was applied again on a patient for the treatment of unresectable and incurable hepatic metastases of a carcinoma of the rectum. Both patients are dead at present. Now we can analyze in depth the clinical history of these patients and evaluate the effectiveness of this therapy. From this exciting experience we learned much, and we also found out about complications till then unknown, which need to be studied and addressed experimentally. Unfortunately we can base our conclusions just on the experience we had with these two patients. We could have been much more detailed and firm in our statements if the number of clinical cases was larger. The BNCT Pavia project has been suspended, but it is more than likely to resume in a short time. Good findings were many. The procedure is feasible; the original concept of complete immersion of the diseased liver in a homogeneous neutron field proved effective and winning. The tumor masses resulted completely necrotic and unknown metastases too appeared radically treated; healthy hepatic tissue was preserved from both morphological and functional points of view; no symptoms of cirrhosis appeared even four years after treatment. For the long term surviving patient, quality of life was excellent. Other findings require to be tackled in depth. The 'post-irradiation syndrome' we observed in both patients, with identical symptoms and biochemical derangements, creates a dramatic-even though totally reversible-clinical condition, that is the probable cause of death for our second patient, suffering from cardiomyopathy, 33 days after treatment. For the first patient, recurrences were a late yet fatal complication, for which
5. Isodose Curves and Treatment Planning for Boron Neutron Capture Therapy.
Science.gov (United States)
Liu, Hungyuan B.
The development of Boron Neutron Capture Therapy (BNCT) has been progressing in both ^{10 }B compound development and testing and neutron beam delivery. Animal tests are now in progress with several ^{10}B compounds and once the results of these animal tests are promising, patient trials can be initiated. The objective of this study is to create a treatment planning method based on the dose calculations by a Monte Carlo code of a mixed radiation field to provide linkage between phantom dosimetry and patient irradiation. The research started with an overall review of the development of BNCT. Three epithermal neutron facilities are described, including the operating Brookhaven Medical Research Reactor (BMRR) beam, the designed Missouri University Research Reactor (MURR) beam, and a designed accelerator based neutron source. The flux and dose distributions in a head model have been calculated for irradiation by these neutron beams. Different beam parameters were inter -compared for effectiveness. Dosimetric measurements in an elliptical lucite phantom and a cylindrical water phantom were made and compared to the MCNP calculations for irradiation by the BMRR beam. Repeated measurements were made and show consistent. To improve the statistical results calculated by MCNP, a neutron source plane was designed to start neutrons at the BMRR irradiation port. The source plane was used with the phantoms for dosimetric calculations. After being verified by different phantom dosimetry and in-air flux measurements at the irradiation port, the source plane was used to calculate the flux and dose distributions in the head model. A treatment planning program was created for use on a PC which uses the MCNP calculated results as input. This program calculates the thermal neutron flux and dose distributions of each component of radiation in the central coronal section of the head model for irradiation by a neutron beam. Different combinations of head orientations and irradiation
6. Carborane-containing metalloporphyrins for BNCT
Energy Technology Data Exchange (ETDEWEB)
Miura, Michiko; Joel, D.D.; Nawrocky, M.M.; Micca, P.L. [and others
1996-12-31
For BNCT of malignant brain tumors, it is crucial that there be relatively high boron concentrations in tumor compared with normal tissues within the neutron-irradiated treatment volume. Fairchild and Bond estimated that major advances in BNCT should be possible if ratios of {sup 10}B concentrations in tumor to those in normal tissue (e.g. brain and blood) were at least 5: 1. Given that the only current boron carrier being tested clinically in the U.S., p-boronophenyl-alanine[BPA], yields tumor blood and tumor brain ratios of about 3:1, the criteria for new boronated compounds should be to at least match these ratios and maintain tumor boron concentrations greater than 30 {mu}g B/g. Although previously tested boronated porphyrins have not only matched but surpassed these ratios, it was at a cost of greater toxicity. Chemical and hematological assays of blood analytes; showed marked thrombocytopenia, a decrease to about one-tenth the normal concentration of platelets circulating in the blood, in addition to abnormalities in concentrations of circulating enzymes, that indicated liver toxicity. The physical appearance and behavior of the affected mice were different from those of mice injected with solvent only. Although thrombocytopenia and other toxic effects had disappeared after a few days, previously tested porphyrins would not be safe to infuse into patients for BNCT of potentially hemorrhagic malignant tumors in the brain such as glioblastoma multiforme and metastatic melanoma. We synthesized a different boronated porphyrin, tetracarboranylphenylporphyrin, [TCP] and inserted nickel, copper, or manganese into its coordination center. Biological studies of NiTCP in mice and of CuTCP in rats show that these compounds elicit little or no toxicity when given at potentially therapeutic doses.
7. Carborane-containing metalloporphyrins for BNCT
International Nuclear Information System (INIS)
For BNCT of malignant brain tumors, it is crucial that there be relatively high boron concentrations in tumor compared with normal tissues within the neutron-irradiated treatment volume. Fairchild and Bond estimated that major advances in BNCT should be possible if ratios of 10B concentrations in tumor to those in normal tissue (e.g. brain and blood) were at least 5: 1. Given that the only current boron carrier being tested clinically in the U.S., p-boronophenyl-alanine[BPA], yields tumor blood and tumor brain ratios of about 3:1, the criteria for new boronated compounds should be to at least match these ratios and maintain tumor boron concentrations greater than 30 μg B/g. Although previously tested boronated porphyrins have not only matched but surpassed these ratios, it was at a cost of greater toxicity. Chemical and hematological assays of blood analytes; showed marked thrombocytopenia, a decrease to about one-tenth the normal concentration of platelets circulating in the blood, in addition to abnormalities in concentrations of circulating enzymes, that indicated liver toxicity. The physical appearance and behavior of the affected mice were different from those of mice injected with solvent only. Although thrombocytopenia and other toxic effects had disappeared after a few days, previously tested porphyrins would not be safe to infuse into patients for BNCT of potentially hemorrhagic malignant tumors in the brain such as glioblastoma multiforme and metastatic melanoma. We synthesized a different boronated porphyrin, tetracarboranylphenylporphyrin, [TCP] and inserted nickel, copper, or manganese into its coordination center. Biological studies of NiTCP in mice and of CuTCP in rats show that these compounds elicit little or no toxicity when given at potentially therapeutic doses
8. Shielding design of a treatment room for an accelerator-based epithermal neutron irradiation facility for BNCT
International Nuclear Information System (INIS)
Protecting the facility personnel and the general public from radiation exposure is a primary safety concern of an accelerator-based epithermal neutron irradiation facility. This work makes an attempt at answering the questions open-quotes How much?close quotes and open-quotes What kind?close quotes of shielding will meet the occupational limits of such a facility. Shielding effectiveness is compared for ordinary and barytes concretes in combination with and without borated polyethylene. A calculational model was developed of a treatment room, patient open-quotes scatterer,close quotes and the epithermal neutron beam. The Monte Carlo code, MCNP, was used to compute the total effective dose equivalent rates at specific points of interest outside of the treatment room. A conservative occupational effective dose rate limit of 0.01 mSv h-1 was the guideline for this study. Conservative Monte Carlo calculations show that constructing the treatment room walls with 1.5 m of ordinary concrete, 1.2 m of barytes concrete, 1.0 m of ordinary concrete preceded by 10 cm of 5% boron-polyethylene, or 0.8 m of barytes concrete preceded by 10 cm of 5% boron-polyethylene will adequately protect facility personnel. 20 refs., 8 figs., 2 tabs
9. Successful BNCT for patients with cutaneous and mucosal melanomas. Report of 4 cases
International Nuclear Information System (INIS)
Since 2003 we have conducted BNCT clinical trials on melanomas at the Kyoto University Research Reactor (KUR) and Japan Research Reactor No.4 (JRR-4). We report 4 patients given BNCT for malignant melanomas: 2 with superficial spreading types on the heel, 1 with mucosal melanoma in the nasal cavity, and 1 with a melanoma on the vulva and in the vagina. The two cutaneous melanomas and the nasal cavity mucosal melanoma showed a complete response (CR) by 6 months after BNCT. The residual melanoma showed a partial response (PR) by 3 months after treatment and no regrowth since then. Although two patients experienced normal-tissue damage that exceeded the tolerance level, all the participants were cured within a few months of treatment. BNCT was shown to be a promising treatment for mucosal, as well as for cutaneous, melanomas. (author)
10. FiR 1 Reactor in Service for Boron Neutron Capture Therapy (BNCT) and Isotope Production
International Nuclear Information System (INIS)
The FiR 1 reactor, a 250 kW Triga reactor, has been in operation since 1962. The main purpose to run the reactor is now the Boron Neutron Capture Therapy (BNCT). Although BNCT dominates the current utilization of the reactor, it also has an important national role in providing local enterprises and research institutions in the fields of industrial measurements, pharmaceuticals, electronics, etc. with isotope produc- tion and activation analysis services. The whole reactor building has been renovated, creating a dedicated clinical BNCT facility at the reactor. Close to 30 patients have been treated since May 1999, when the licence for patient treatment was granted to the responsible BNCT treatment organization. The treatment organization has a close connection to the Helsinki University Central Hospital. (author)
11. Positron emission tomography and [{sup 18}F]BPA: A perspective application to assess tumour extraction of boron in BNCT
Energy Technology Data Exchange (ETDEWEB)
Menichetti, L. [Department of PET and Radiopharmaceutical Chemistry, C.N.R. Institute of Clinical Physiology, Pisa (Italy)], E-mail: [email protected]; Cionini, L. [Unit of Radiotherapy, AOUP-University Hospital, Pisa (Italy); Sauerwein, W.A. [Department of Radiation Oncology, University Duisburg-Essen, University Hospital Essen (Germany); Altieri, S. [University of Pavia, Department of Nuclear Physics, Pavia (Italy); Solin, O.; Minn, H. [Turku PET Centre, University of Turku (Finland); Salvadori, P.A. [Department of PET and Radiopharmaceutical Chemistry, C.N.R. Institute of Clinical Physiology, Pisa (Italy)
2009-07-15
Positron emission tomography (PET) has become a key imaging tool in clinical practice and biomedical research to quantify and study biochemical processes in vivo. Physiologically active compounds are tagged with positron emitters (e.g. {sup 18}F, {sup 11}C, {sup 124}I) while maintaining their biological properties, and are administered intravenously in tracer amounts (10{sup -9}-10{sup -12} M quantities). The recent physical integration of PET and computed tomography (CT) in hybrid PET/CT scanners allows a combined anatomical and functional imaging: nowadays PET molecular imaging is emerging as powerful pharmacological tool in oncology, neurology and for treatment planning as guidance for radiation therapy. The in vivo pharmacokinetics of boron carrier for BNCT and the quantification of {sup 10}B in living tissue were performed by PET in the late nineties using compartmental models based on PET data. Nowadays PET and PET/CT have been used to address the issue of pharmacokinetic, metabolism and accumulation of BPA in target tissue. The added value of the use of L-[{sup 18}F]FBPA and PET/CT in BNCT is to provide key data on the tumour extraction of {sup 10}B-BPA versus normal tissue and to predict the efficacy of the treatment based on a single-study patient analysis. Due to the complexity of a binary treatment like BNCT, the role of PET/CT is currently to design new criteria for patient enrolment in treatment protocols: the L-[{sup 18}F]BPA/PET methodology could be considered as an important tool in newly designed clinical trials to better estimate the concentration ratio of BPA in the tumour as compared to neighbouring normal tissues. Based on these values for individual patients the decision could be made whether BNCT treatment could be advantageous due to a selective accumulation of BPA in an individual tumour. This approach, applicable in different tumour entities like melanoma, glioblastoma and head and neck malignancies, make this methodology as reliable
12. Dosimetric feasibility study for an extracorporeal BNCT application on liver metastases at the TRIGA Mainz.
Science.gov (United States)
Blaickner, M; Kratz, J V; Minouchehr, S; Otto, G; Schmidberger, H; Schütz, C; Vogtländer, L; Wortmann, B; Hampel, G
2012-01-01
This study investigates the dosimetric feasibility of Boron Neutron Capture Therapy (BNCT) of explanted livers in the thermal column of the research reactor in Mainz. The Monte Carlo code MCNP5 is used to calculate the biologically weighted dose for different ratios of the (10)B-concentration in tumour to normal liver tissue. The simulation results show that dosimetric goals are only partially met. To guarantee effective BNCT treatment the organ has to be better shielded from all gamma radiation. PMID:21872481
13. Application of HVJ envelope system to boron neutron capture therapy (BNCT)
International Nuclear Information System (INIS)
Boron Neutron Capture Therapy (BNCT) has been used clinically for the treatment of malignant tumors. Two drugs, p-boronophenylalanine (BPA) and sulfhydral borane (BSH), have been used as boron delivery agents. These drugs seem to be taken up preferentially in solid tumors, but it is uncertain whether therapeutic quantities of boron atoms are taken up by micro-invasive or distant tumor cells. High accumulation and high selective delivery of boron into tumor tissues are the most important requirements to achieve efficient BNCT for malignant tumor. The HVJ envelope (HVJ-E) vector system is a novel fusion-mediated gene delivery system based on inactivated hemagglutinating virus of Japan (HVJ; Sendai virus). Although we developed this vector system for gene transfer, it can also deliver proteins, synthetic oligonucleotides, and drugs. HVJ-liposome, which is liposome fused with HVJ-E, has higher boron trapping efficiency than HVJ-E alone. We report the boron delivery into cultured cells with HVJ-liposome systems. The cellular 10B concentration after 60 min incubation with HVJ-E containing BSH was 24.9 μg/g cell pellet for BHK-21 cells (baby hamster kidney cells) and 19.4 μg/g cell pellet for SCC VII cells (murine squamous cell carcinoma). These concentrations are higher than that of 60 min incubated cells with BSH containing (100μg 10B/ml) medium. These results indicate the HVJ-E fused with tumor cell membrane and rapidly delivered boron agents, and that the HVJ-E-mediated delivery system could be applicable to BNCT. Plans are underway to begin neutron radiation experiments in vivo and in vitro. (author)
14. Effect of different BNCT protocols on DNA synthesis in precancerous and normal tissues in an experimental model of oral cancer
International Nuclear Information System (INIS)
We previously reported the therapeutic success of different BNCT protocols in the treatment of oral cancer, employing the hamster cheek pouch model. The aim of the present study was to evaluate the effect of these BNCT protocols on DNA synthesis in precancerous and normal tissue in this model and assess the potential lag in the development of second primary tumors in precancerous tissue. The data are relevant to potential control of field cancerized tissue and tolerance of normal tissue. We evaluated DNA synthesis in precancerous and normal pouch tissue 1-30 days post-BNCT mediated by BPA, GB-10 or BPA + GB-10 employing incorporation of bromo-deoxyuridine as an end-point. The BNCT-induced potential lag in the development of second primary tumors in precancerous tissue was monitored. A drastic, statistically significant reduction in DNA synthesis occurred in pacancerous tissue as early as 1 day post-BNCT and was sustained at virtually all time points until 30 days post-BNCT for all protocols. The histological categories evaluated individually within precancerous tissue (dysplasia, hyperplasia and NUMF [no unusual microscopic features]) responded similarly. DNA synthesis in normal tissue treated with BNCT oscillated around the very low pre-treatment values. A BNCT-induced lag in the development of second primary tumors was observed. BNCT induced a drastic fall in DNA synthesis in precancerous tissue that would be associated to the observed lag in the development of second primary tumors. The minimum variations in DNA synthesis in BNCT-treated normal tissue would correlate with the absence of normal tissue radiotoxicity. The present data would contribute to optimize therapeutic efficacy in the treatment of field-cancerized areas. (author)
15. Treatment planning for restorative implantology.
Science.gov (United States)
Boyce, Ricardo A; Klemons, Gary
2015-04-01
In this article, current literature on fixed and removable prosthodontics is reviewed along with evidence-based systematic reviews, including advice from those in the dental profession with years of experience, which help restorative dentists manage and treat their cases successfully. Treatment planning for restorative implantology should be looked at in 4 sections: (1) review of past medical history, (2) oral examination and occlusion, (3) dental imaging (ie, cone-beam computed tomography), and (4) fixed versus removable prosthodontics. These 4 concepts of treatment planning, along with proper surgical placements of the implant(s), result in successful cases. PMID:25835794
16. BNCT and Targeted Radiotherapy (TRT) developments in Romania
International Nuclear Information System (INIS)
There are a number of treatment modalities for cancer including surgery, chemotherapy and radiation therapy. However, these treatments are not always effective. The search for new and more efficient ways to combat cancer has opened new perspectives. Boron neutron capture therapy (BNCT) is a new approach in cancer treatment that has been proposed to combat glioblastomas of the brain, neck cancer and malignant melanomas, tumors that are resistant to traditional cancer therapies. BNCT is based on the 10B(n,α)7Li nuclear reaction, which can potentially deliver a very high and fatal radiation dose to cancerous cells by concentrating boron in them. It is a promising, though complicated treatment. This type of therapy offers a number of potentially significant advantages compared to traditional radiation therapy. Treatment is better targeted to cancerous cells so that when a tumour is irradiated with neutrons, the damage to normal tissue is respectively less. It is also less demanding for the patient as treatment is only one to two sessions, compared to conventional radiation therapy where patients can be treated up to 30 times. It provides an excellent example of the importance of innovation in the search for a cure to cancer. The recent developments in BNCT in Romania as well as the major drawbacks will be presented. (authors)
17. PREFACE: First European Workshop on Monte Carlo Treatment Planning
Science.gov (United States)
Reynaert, Nick
2007-07-01
The "First European Workshop on Monte Carlo treatment planning", was an initiative of the European working group on Monte Carlo treatment planning (EWG-MCTP). It was organised at Ghent University (Belgium) on 22-25October 2006. The meeting was very successful and was attended by 150 participants. The impressive list of invited speakers and the scientific contributions (posters and oral presentations) have led to a very interesting program, that was well appreciated by all attendants. In addition, the presence of seven vendors of commercial MCTP software systems provided serious added value to the workshop. For each vendor, a representative has given a presentation in a dedicated session, explaining the current status of their system. It is clear that, for "traditional" radiotherapy applications (using photon or electron beams), Monte Carlo dose calculations have become the state of the art, and are being introduced into almost all commercial treatment planning systems. Invited lectures illustrated that scientific challenges are currently associated with 4D applications (e.g. respiratory motion) and the introduction of MC dose calculations in inverse planning. But it was striking that the Monte Carlo technique is also becoming very important in more novel treatment modalities such as BNCT, hadron therapy, stereotactic radiosurgery, Tomotherapy, etc. This emphasizes the continuous growing interest in MCTP. The people who attended the dosimetry session will certainly remember the high level discussion on the determination of correction factors for different ion chambers, used in small fields. The following proceedings will certainly confirm the high scientific level of the meeting. I would like to thank the members of the local organizing committee for all the hard work done before, during and after this meeting. The organisation of such an event is not a trivial task and it would not have been possible without the help of all my colleagues. I would also like to thank
18. An analysing of heat treatment process planning
OpenAIRE
B. Smoljan
2007-01-01
Purpose: Process planning of heat treatment has been investigated. The established approach of heat treatingprocess planning is suitable for effective integration of heat treatment in computer added manufacturing.Design/methodology/approach: Process plan of heat treating process has been established based on fundamentalprocess planning principals. The heat treatment was treated in the same as other manufacture processes.Findings: The general approach for process planning of heat treatment pro...
19. Towards a new therapy protocol for liver metastases. Effect of boron compounds and BNCT on normal liver regeneration
International Nuclear Information System (INIS)
The Taormina project developed a new method for BNCT treatment of multifocal unresectable liver metastases based on whole liver autograft. The Roffo Institute liver surgeons propose a new technique based on partial liver autograft that would pose less risk to the patient but would require significant healthy liver regeneration following BNCT. The aim of the present study was to assess the effect of BPA, GB-10 (Na210B10H10) and (GB-10 + BPA) and of BNCT mediated by these boron compounds on normal liver regeneration in the Wistar rat. Normal liver regeneration, body weight, hemogram, liver and kidney function were assessed following partial hepatectomy post administration of BPA, GB-10 or (GB-10 + BPA) and post in vivo BNCT at the RA-6 Reactor. These end-points were evaluated 9 days following partial hepatectomy, the time at which complete liver regeneration occurs in untreated controls. The corresponding biodistribution studies were conducted to perform dosimetric calculations. BPA, GB-10 and (GB-10 + PBA) and in vivo BNCT mediated by these boron compounds in dose ranges compatible with therapy did not cause alterations in the outcome of normal liver regeneration, and did not induce alterations in body weight, hemogram, liver or kidney function. The experimental data available to date support the development of a new BNCT protocol for the treatment of liver metastases that requires the regeneration of normal liver past-BNCT. (author)
20. Automatic planning of head and neck treatment plans.
Science.gov (United States)
Hazell, Irene; Bzdusek, Karl; Kumar, Prashant; Hansen, Christian R; Bertelsen, Anders; Eriksen, Jesper G; Johansen, Jørgen; Brink, Carsten
2016-01-01
Treatment planning is time-consuming and the outcome depends on the person performing the optimization. A system that automates treatment planning could potentially reduce the manual time required for optimization and could also provide a method to reduce the variation between persons performing radiation dose planning (dosimetrist) and potentially improve the overall plan quality. This study evaluates the performance of the Auto-Planning module that has recently become clinically available in the Pinnacle3 radiation therapy treatment planning system. Twenty-six clinically delivered head and neck treatment plans were reoptimized with the Auto-Planning module. Comparison of the two types of treatment plans were performed using DVH metrics and a blinded clinical evaluation by two senior radiation oncologists using a scale from one to six. Both evaluations investigated dose coverage of target and dose to healthy tissues. Auto-Planning was able to produce clinically acceptable treatment plans in all 26 cases. Target coverages in the two types of plans were similar, but automatically generated plans had less irradiation of healthy tissue. In 94% of the evaluations, the autoplans scored at least as high as the previously delivered clinical plans. For all patients, the Auto-Planning tool produced clinically acceptable head and neck treatment plans without any manual intervention, except for the initial target and OAR delineations. The main benefit of the method is the likely improvement in the overall treatment quality since consistent, high-quality plans are generated which even can be further optimized, if necessary. This makes it possible for the dosimetrist to focus more time on difficult dose planning goals and to spend less time on the more tedious parts of the planning process.
1. BNCT with linac, feasibility study
International Nuclear Information System (INIS)
High energy photon beams from Medical Linear Accelerators (linacs) which are used in radiotherapy produce undesirable neutrons, beside the clinically useful electron and photon beams. Neutrons are produced from the photonuclear reaction (γ,n) of high energy photons with high Z-materials which compose the accelerator head. In this paper the possible use of these undesirable neutrons for BNCT is investigated, making use of high energy linacs already installed in hospitals, primarily for high energy electron and photon therapy and applying them in the context of BNCT. The photoneutron components emitted by the accelerator is the source for Monte Carlo simulations of the interactions that take place within the head of a voxel-based phantom. The neutron flux across the phantom head is calculated using different moderator arrangements and different techniques in the aim of increasing the thermal neutron flux at the targeted site. Also, we shall test different configurations of the linac head to maximize the exposure of high-Z materials to the photon beam, including the removal of the flattening filter, so as to boost the photoneutron production in the linac head. Experimental work will be conducted in hospitals to validate the Monte Carlo simulations. To make use of linacs for BNCT will be advantageous in the sense that the setting in a hospital department is much more acceptable by the public than a reactor installation. This will mean less complications regarding patient positioning and movement with respect to the beams, additional patient transportation and management will be more cost effective. (author)
2. Boron Neutron Capture Therapy (BNCT) in an experimental model of lung metastases in BDIX rats
International Nuclear Information System (INIS)
Boron Neutron Capture Therapy (BNCT) in an experimental model of lung metastases in BDIX rats Introduction: Boron Neutron Capture Therapy (BNCT) is based on selective tumor uptake of boron compounds, followed by neutron irradiation. BNCT was proposed for the treatment of unresectable, diffuse lung metastases. The aim of the present study was to perform BNCT studies in an experimental model of lung metastases. Materials and Methods: 3 x 106/0.5 ml colon carcinoma cells (DHD/K12/TRb) were injected iv in syngeneic BDIX rats. Three weeks post-inoculation, rats with diffuse lung metastases were used for in vivo BNCT studies in the RA-3 Nuclear Reactor. Based on previous biodistribution studies and computational dosimetry with Monte Carlo simulation, 2 doses were prescribed, i.e. 4 Gy and 8 Gy minimum absorbed dose to tumor. The animals were assigned to 5 experimental groups (n= 4 to 8) at each dose level: T0 (euthanized pre-treatment), BPA-BNCT, Comb-BNCT (BPA+GB-10), Beam only (background dose) and Sham (same manipulation, no treatment). Boron concentration was measured in a blood sample taken pre-irradiation to verify that the value was in the range established in previous biodistribution studies. The animals were followed clinically for 2 weeks after neutron irradiation and then euthanized to assess the response of tumor and normal lung, macroscopically and histologically. To date we have evaluated the end-point weight of lung (normal lung + metastases) and % lung weight/body weight as an indicator of tumor growth. Results: The statistical analysis (ANOVA) of % lung weight/body weight showed statistically significant differences (p<0.05) between groups T0 (0.79 ± 0.38) and Sham (1.87 ± 0.91). No statistically significant differences were observed between the Beam only groups (at both dose levels) and Sham. Similar and statistically significant tumor control was induced in the groups BPA-BNCT Low dose (LD) (0.56 ± 0.11), BPA-BNCT High dose (HD) (0.80 ± 0.16), Comb-BNCT
3. Automatic planning of head and neck treatment plans
DEFF Research Database (Denmark)
Hazell, Irene; Bzdusek, Karl; Kumar, Prashant;
2016-01-01
qual-ity since consistent, high-quality plans are generated which even can be further optimized, if necessary. This makes it possible for the dosimetrist to focus more time on difficult dose planning goals and to spend less time on the more tedious parts of the planning process.......Treatment planning is time-consuming and the outcome depends on the person performing the optimization. A system that automates treatment planning could potentially reduce the manual time required for optimization and could also pro-vide a method to reduce the variation between persons performing...... radiation dose planning (dosimetrist) and potentially improve the overall plan quality. This study evaluates the performance of the Auto-Planning module that has recently become clinically available in the Pinnacle3 radiation therapy treatment planning system. Twenty-six clinically delivered head and neck...
4. A Tandem-electrostatic-quadrupole for accelerator-based BNCT
International Nuclear Information System (INIS)
A project to develop a Tandem-electrostatic-quadrupole (TESQ) accelerator for accelerator-based boron neutron capture therapy (AB-BNCT) is described. A folded Tandem, with 1.25 MV terminal voltage, combined with an electrostatic quadrupole (ESQ) chain is being proposed. The project goal is a machine capable of delivering 30 mA of 2.5 MeV protons to be used in conjunction with a neutron production target based on the 7Li(p, n)7Be reaction slightly beyond its resonance at 2.25 MeV. This machine is conceptually shown to be capable of accelerating a 30 mA proton beam to 2.5 MeV. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the 7Li(p, n)7Be reaction, to perform BNCT treatment for deep-seated tumors in less than an hour. This electrostatic machine is the technologically simplest and cheapest solution for optimized AB-BNCT
5. Tandem-ESQ for accelerator-based BNCT
International Nuclear Information System (INIS)
A project to develop a Tandem-ElectroStatic-Quadrupole (TESQ) accelerator for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT) is described. A folded tandem, with 1.25 MV terminal voltage, combined with an ElectroStatic Quadrupole (ESQ) chain is being proposed. The project goal is a machine capable of delivering 30 mA of 2.5 MeV protons to be used in conjunction with a neutron production target based on the 7Li(p,n)7Be reaction beyond its resonance at 2.25 MeV. This machine is conceptually shown to be capable of accelerating a 30 mA proton beam to 2.5 MeV. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the '7Li(p,n)7Be reaction, to perform BNCT treatment for deep-seated tumors in less than an hour. This electrostatic machine is the technologically simplest and cheapest solution for optimized AB-BNCT. (author)
6. BNCT activities at Slovenian TRIGA research reactor
International Nuclear Information System (INIS)
It has been reported that satisfactory thermal/epithermal neutron beams for Boron Neutron Capture Therapy (BNCT) could be designed at TRIGA research reactors These reactors are generally perceived as being safe to install and operate in populated areas. This contribution presents the most recent BNCT research activities on the 'Jozef Stefan' Institute, where epithermal neutron beam for 'in-vitro' irradiation has been developed and experimentally verified. Furthermore, The Monte Carlo feasibility study of development of the epithermal neutron beam for BNCT clinical trials of human patients in thermalising column (TC) of TRIGA reactor has been carried out. The simulation results prove, that a BNCT irradiation facility with performances, comparable to existing beam throughout the world, could be installed in TC of the TRIGA reactor. (author)
7. Feasibility study of using laser-generated neutron beam for BNCT
International Nuclear Information System (INIS)
The feasibility of using a laser-accelerated proton beam to produce a neutron source, via (p,n) reaction, for Boron Neutron Capture Therapy (BNCT) applications has been studied by MCNPX Monte Carlo code. After optimization of the target material and its thickness, a Beam Shaping Assembly (BSA) has been designed and optimized to provide appropriate neutron beam according to the recommended criteria by International Atomic Energy Agency. It was found that the considered laser-accelerated proton beam can provide epithermal neutron flux of ∼2×106 n/cm2 shot. To achieve an appropriate epithermal neutron flux for BNCT treatment, the laser must operate at repetition rates of 1 kHz, which is rather ambitious at this moment. But it can be used in some BNCT researches field such as biological research. - Highlights: • Feasibility of using laser-accelerated proton beam for BNCT has been investigated. • The considered beam can provide epithermal neutron flux of ~2×106 (n/cm2.shot). • For BNCT treatment, the laser must operate at repetition rates of 1 kHz
8. QA of treatment planning systems
International Nuclear Information System (INIS)
Protocols for commissioning and performance of treatment planning systems have been proposed and performed at several occasions. These tests are valuable, but it is evident that we need a more comprehensive QA for the planning systems. International bodies are working on this subject today, and recommendations will soon appear. However, very little results and experiences are published from running QA protocols. In our department we have been using an in house 2D system for many years, and as both developer and user we needed a QA protocol. Two years ago we bought a commercial 3D system, and a new QA protocol had to be set up for this situation. This protocol include: 1) description of duties for responsible persons, 2) education/competence levels for users, 3) acceptance tests for both system and treatment unit data, and 4) constancy tests for the same. Experience so far reveals that a QA protocol is necessary for use of sophisticated 3D systems, even though no error in the system itself have been found that would have given erroneous dosage. Clear definitions of who is responsible for the different aspects of using the system has proven essential. An introductory course have to be given to all new users to avoid misuse. Acceptance tests of system is necessary, not only to accept the system but also to learn how to use it correctly and detect its limitations. Acceptance tests of basic treatment unit data is mandatory before they can be taken into clinical use. Also constancy tests have proven necessary when modifications are done. The experience with such a protocol gives lot of input back to the manufacturer too. It also raises principal questions about what should be checked and what is the responsibility of the manufacturers. More details will be presented in the meeting
9. Boron neutron capture therapy (BNCT) for liver metastasis in an experimental model: dose–response at five-week follow-up based on retrospective dose assessment in individual rats
Energy Technology Data Exchange (ETDEWEB)
Emiliano C. C. Pozzi; Veronica A. Trivilin; Lucas L. Colombo; Andrea Monti Hughes; Silvia I. Thorp; Jorge E. Cardoso; Marcel A. Garabalino; Ana J. Molinari; Elisa M. Heber; Paula Curotto; Marcelo Miller; Maria E. Itoiz; Romina F. Aromando; David W. Nigg; Amanda E. Schwint
2013-11-01
Boron neutron capture therapy (BNCT) was proposed for untreatable colorectal liver metastases. Employing an experimental model of liver metastases in rats, we recently demonstrated that BNCT mediated by boronophenylalanine (BPA-BNCT) at 13 Gy prescribed to tumor is therapeutically useful at 3-week follow-up. The aim of the present study was to evaluate dose–response at 5-week follow-up, based on retrospective dose assessment in individual rats. BDIX rats were inoculated with syngeneic colon cancer cells DHD/K12/TRb. Tumor-bearing animals were divided into three groups: BPA-BNCT (n = 19), Beam only (n = 8) and Sham (n = 7) (matched manipulation, no treatment). For each rat, neutron flux was measured in situ and boron content was measured in a pre-irradiation blood sample for retrospective individual dose assessment. For statistical analysis (ANOVA), individual data for the BPA-BNCT group were pooled according to absorbed tumor dose, BPA-BNCT I: 4.5–8.9 Gy and BPA-BNCT II: 9.2–16 Gy. At 5 weeks post-irradiation, the tumor surface area post-treatment/pre-treatment ratio was 12.2 +/- 6.6 for Sham, 7.8 +/- 4.1 for Beam only, 4.4 +/- 5.6 for BPA-BNCT I and 0.45 +/- 0.20 for BPA-BNCT II; tumor nodule weight was 750 +/- 480 mg for Sham, 960 +/- 620 mg for Beam only, 380 +/- 720 mg for BPA-BNCT I and 7.3 +/- 5.9 mg for BPA-BNCT II. The BPA-BNCT II group exhibited statistically significant tumor control with no contributory liver toxicity. Potential threshold doses for tumor response and significant tumor control were established at 6.1 and 9.2 Gy, respectively.
10. Dose estimation of animal experiments at the THOR BNCT beam by NCTPlan and Xplan
International Nuclear Information System (INIS)
Dose estimation of animal experiments affects many subsequent derived quantities, such as RBE and CBE values. It is important to ensure the trustiness of calculated dose of the irradiated animals. However, the dose estimation was normally calculated using simplified geometries and tissue compositions, which led to rough results. This paper introduces the use of treatment planning systems NCTplan and Xplan for the dose estimation. A mouse was taken as an example and it was brought to hospital for micro-PET/CT scan. It was found that the critical organ doses of an irradiated mouse calculated by simplified model were unreliable in comparison to Xplan voxel model. The difference could reach the extent of several tenths percent. It is recommended that a treatment planning system should be introduced to future animal experiments to upgrade the data quality. - Highlights: • This study presents the new BNCT treatment planning system Xplan for animal experiments. • Xplan is based on a pixel-to-pixel conversion which has the same resolution as the CT images. • NCTplan and a simplified geometry for rat were used for the sake of comparison. • The spatial resolution applied in calculation is crucial to the reliability of estimated dose
11. Spatial and spectral characteristics of a compact system neutron beam designed for BNCT facility
International Nuclear Information System (INIS)
The development of suitable neutron sources and neutron beam is critical to the success of Boron Neutron Capture Therapy (BNCT). In this work a compact system designed for BNCT is presented. The system consists of 252Cf fission neutron source and a moderator/reflector/filter/shield assembly. The moderator/reflector/filter arrangement has been optimized to maximize the epithermal neutron component which is useful for BNCT treatment of deep seated tumors with the suitably low level of beam contamination. The MCMP5 code has been used to calculate the different components of neutrons, secondary gamma rays originating from 252Cf source and the primary gamma rays emitted directly by this source at the exit face of the compact system. The fluence rate distributions of such particles were also computed along the central axis of a human head phantom
12. Spatial and spectral characteristics of a compact system neutron beam designed for BNCT facility
Energy Technology Data Exchange (ETDEWEB)
Ghassoun, J. [EPRA, Departement de Physique, Faculte des Sciences Semlalia, B.P. 2390, 40000 Marrakech (Morocco)], E-mail: [email protected]; Chkillou, B.; Jehouani, A. [EPRA, Departement de Physique, Faculte des Sciences Semlalia, B.P. 2390, 40000 Marrakech (Morocco)
2009-04-15
The development of suitable neutron sources and neutron beam is critical to the success of Boron Neutron Capture Therapy (BNCT). In this work a compact system designed for BNCT is presented. The system consists of {sup 252}Cf fission neutron source and a moderator/reflector/filter/shield assembly. The moderator/reflector/filter arrangement has been optimized to maximize the epithermal neutron component which is useful for BNCT treatment of deep seated tumors with the suitably low level of beam contamination. The MCMP5 code has been used to calculate the different components of neutrons, secondary gamma rays originating from {sup 252}Cf source and the primary gamma rays emitted directly by this source at the exit face of the compact system. The fluence rate distributions of such particles were also computed along the central axis of a human head phantom.
13. Spatial and spectral characteristics of a compact system neutron beam designed for BNCT facility.
Science.gov (United States)
Ghassoun, J; Chkillou, B; Jehouani, A
2009-04-01
The development of suitable neutron sources and neutron beam is critical to the success of Boron Neutron Capture Therapy (BNCT). In this work a compact system designed for BNCT is presented. The system consists of (252)Cf fission neutron source and a moderator/reflector/filter/shield assembly. The moderator/reflector/filter arrangement has been optimized to maximize the epithermal neutron component which is useful for BNCT treatment of deep seated tumors with the suitably low level of beam contamination. The MCMP5 code has been used to calculate the different components of neutrons, secondary gamma rays originating from (252)Cf source and the primary gamma rays emitted directly by this source at the exit face of the compact system. The fluence rate distributions of such particles were also computed along the central axis of a human head phantom. PMID:19168369
14. Characterisation of an accelerator-based neutron source for BNCT versus beam energy
CERN Document Server
Agosteo, S; D'Errico, F; Nath, R; Tinti, R
2002-01-01
Neutron capture in sup 1 sup 0 B produces energetic alpha particles that have a high linear energy transfer in tissue. This results in higher cell killing and a higher relative biological effectiveness compared to photons. Using suitably designed boron compounds which preferentially localize in cancerous cells instead of healthy tissues, boron neutron capture therapy (BNCT) has the potential of providing a higher tumor cure rate within minimal toxicity to normal tissues. This clinical approach requires a thermal neutron source, generally a nuclear reactor, with a fluence rate sufficient to deliver tumorcidal doses within a reasonable treatment time (minutes). Thermal neutrons do not penetrate deeply in tissue, therefore BNCT is limited to lesions which are either superficial or otherwise accessible. In this work, we investigate the feasibility of an accelerator-based thermal neutron source for the BNCT of skin melanomas. The source was designed via MCNP Monte Carlo simulations of the thermalization of a fast ...
15. Strategies for automatic online treatment plan reoptimization using clinical treatment planning system: A planning parameters study
Energy Technology Data Exchange (ETDEWEB)
Li, Taoran; Wu, Qiuwen; Zhang, You; Vergalasova, Irina; Lee, W. Robert; Yin, Fang-Fang; Wu, Q. Jackie [Duke Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States)
2013-11-15
Purpose: Adaptive radiation therapy for prostate cancer using online reoptimization provides an improved control of interfractional anatomy variations. However, the clinical implementation of online reoptimization is currently limited by the low efficiency of current strategies and the difficulties associated with integration into the current treatment planning system. This study investigates the strategies for performing fast (∼2 min) automatic online reoptimization with a clinical fluence-map-based treatment planning system; and explores the performance with different input parameters settings: dose-volume histogram (DVH) objective settings, starting stage, and iteration number (in the context of real time planning).Methods: Simulated treatments of 10 patients were reoptimized daily for the first week of treatment (5 fractions) using 12 different combinations of optimization strategies. Options for objective settings included guideline-based RTOG objectives, patient-specific objectives based on anatomy on the planning CT, and daily-CBCT anatomy-based objectives adapted from planning CT objectives. Options for starting stages involved starting reoptimization with and without the original plan's fluence map. Options for iteration numbers were 50 and 100. The adapted plans were then analyzed by statistical modeling, and compared both in terms of dosimetry and delivery efficiency.Results: All online reoptimized plans were finished within ∼2 min with excellent coverage and conformity to the daily target. The three input parameters, i.e., DVH objectives, starting stage, and iteration number, contributed to the outcome of optimization nearly independently. Patient-specific objectives generally provided better OAR sparing compared to guideline-based objectives. The benefit in high-dose sparing from incorporating daily anatomy into objective settings was positively correlated with the relative change in OAR volumes from planning CT to daily CBCT. The use of the
16. Conceptual design of epithermal neutron beam for BNCT in the thermalizing column of TRIGA reactor
International Nuclear Information System (INIS)
The Monte Carlo feasibility study of development of the epithermal neutron beam for BNCT clinical trials in thermalising column (TC) of TRIGA reactor is presented. The investigation of the possible use of fission converter as well as the set-up of TRIGA reactor core is performed. The optimization of the irradiation facility components is carried out and the configuration with the most favorable cost/performance ratio is proposed. The results prove, that a BNCT irradiation facility with performances, comparable to existing beams throughout the world, could be installed in TC/DC of the TRIGA reactor, quite suitable for the clinical treatments of human patients.(author)
17. Progress on the accelerator based SPES-BNCT project at INFN Legnaro
Energy Technology Data Exchange (ETDEWEB)
Pisent, A [INFN-LNL, Legnaro (Padova) (Italy); Colautti, P [INFN-LNL, Legnaro (Padova) (Italy); Esposito, J [INFN-LNL, Legnaro (Padova) (Italy); Nardo, L De [Physics Department, Padova University (Italy); Conte, V [INFN-LNL, Legnaro (Padova) (Italy); Agosteo, D [Nuclear Engineering Department, Milano Polytechnic (Italy); Jori, G [Biology Department, Padova University (Italy); Posocco, P A [INFN-LNL, Legnaro (Padova) (Italy); Tecchio, L B [INFN-LNL, Legnaro (Padova) (Italy); Tinti, R [ENEA - FIS-NUC, Bologna (Italy); Rosi, G [ENEA - FIS-ION, Rome (Italy)
2006-05-15
In the framework of an advanced Exotic Ion Beam facility project, named SPES (Study and Production of Exotic Species), that will allow a frontier program in Nuclear and Interdisciplinary Physics, an intense thermal neutron beam facility, devoted to perform Boron Neutron Capture Therapy (BNCT) experimental treatments on skin melanoma tumor is currently under construction based on the SPES proton driver. A vast radiobiological investigation in vitro and in vivo has started with the new {sup 10}B carriers developed. Special microdosimetric detectors have been constructed to properly measure all the BNCT dose components and their qualities. Both microdosimetric and radiobiological measurements are being performed at the Enea-Casaccia TAPIRO reactor.
18. Diagnostic reasoning and treatment planning: II. Treatment.
Science.gov (United States)
Nurcombe, B
1987-12-01
The concepts of therapy-oriented and problem-oriented plans are discussed and their advantages and disadvantages considered. Goal-directed planning is proposed as an alternative to intuitive decision making. Goal-directed planning involves the abstraction of pivotal problems from a diagnostic formulation, the restatement of problems as goals, the selection of appropriate therapy, the designation of a target date, the stipulation of objectives, the selection of methods of evaluation and the monitoring of progress. Systematic goal-directed planning fosters teamwork, promotes accountability, obviates therapeutic drift and enhances outcome evaluation. Its chief disadvantage is its unfamiliarity. PMID:3502386
19. Cyclotron-based neutron source for BNCT
Energy Technology Data Exchange (ETDEWEB)
Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K. [Sumitomo Heavy Industries, Ltd (Japan); Tanaka, H.; Sakurai, Y.; Maruhashi, A. [Kyoto University Research Reactor Institute (Japan)
2013-04-19
Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation and treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8 Multiplication-Sign 109 neutrons/cm{sup 2}/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with {sup 10}B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.
20. First tomographic image of neutron capture rate in a BNCT facility
International Nuclear Information System (INIS)
This work discusses the development of online dosimetry of the boron dose via Single Photon Emission Computed Tomography (SPECT) during a BNCT treatment irradiation. Such a system will allow the online computation of boron dose maps without the large current uncertainties in the assessment of the boron concentration in different tissues. The first tomographic boron dose image with a SPECT prototype is shown.
1. First tomographic image of neutron capture rate in a BNCT facility
Energy Technology Data Exchange (ETDEWEB)
Minsky, D.M., E-mail: [email protected] [Gerencia de Investigacion y Aplicaciones, CAC, CNEA, Av. Gral. Paz 1499 (B1650KNA), San Martin, Prov. Bs. As. (Argentina)] [Escuela de Ciencia y Tecnologia, , UNSAM, M. de Irigoyen 3100 (1650), San Martin, Prov. Bs. As. (Argentina)] [Conicet, Av. Rivadavia 1917 (C1033AAJ), Buenos Aires (Argentina); Valda, A.A. [Gerencia de Investigacion y Aplicaciones, CAC, CNEA, Av. Gral. Paz 1499 (B1650KNA), San Martin, Prov. Bs. As. (Argentina)] [Escuela de Ciencia y Tecnologia, , UNSAM, M. de Irigoyen 3100 (1650), San Martin, Prov. Bs. As. (Argentina); Kreiner, A.J. [Gerencia de Investigacion y Aplicaciones, CAC, CNEA, Av. Gral. Paz 1499 (B1650KNA), San Martin, Prov. Bs. As. (Argentina)] [Escuela de Ciencia y Tecnologia, , UNSAM, M. de Irigoyen 3100 (1650), San Martin, Prov. Bs. As. (Argentina)] [Conicet, Av. Rivadavia 1917 (C1033AAJ), Buenos Aires (Argentina); Green, S.; Wojnecki, C. [School of Physics and Astronomy, University of Birmingham, B15 2 TT (United Kingdom)] [Department of Medical Physics, University Hospital Birmingham, Birmingham B15 2TH (United Kingdom); Ghani, Z. [Department of Medical Physics, University Hospital Birmingham, Birmingham B15 2TH (United Kingdom)
2011-12-15
This work discusses the development of online dosimetry of the boron dose via Single Photon Emission Computed Tomography (SPECT) during a BNCT treatment irradiation. Such a system will allow the online computation of boron dose maps without the large current uncertainties in the assessment of the boron concentration in different tissues. The first tomographic boron dose image with a SPECT prototype is shown.
2. The Boron Neutron Capture Therapy (BNCT) Project at the TRIGA Reactor in Mainz, Germany
DEFF Research Database (Denmark)
Hampel, G.; Grunewald, C.; Schütz, C.;
2011-01-01
The thermal column of the TRIGA reactor in Mainz is being used very effectively for medical and biological applications. The BNCT (boron neutron capture therapy) project at the University of Mainz is focussed on the treatment of liver tumours, similar to the work performed at Pavia (Italy) a few...
3. A D-D/D-T fusion reaction based neutron generator system for liver tumor BNCT
Energy Technology Data Exchange (ETDEWEB)
Koivunoro, H.; Lou, T.P.; Leung, K. N.; Reijonen, J.
2003-04-02
Boron-neutron capture therapy (BNCT) is an experimental radiation treatment modality used for highly malignant tumor treatments. Prior to irradiation with low energetic neutrons, a 10B compound is located selectively in the tumor cells. The effect of the treatment is based on the high LET radiation released in the {sup 10}B(n,{alpha}){sup 7}Li reaction with thermal neutrons. BNCT has been used experimentally for brain tumor and melanoma treatments. Lately applications of other severe tumor type treatments have been introduced. Results have shown that liver tumors can also be treated by BNCT. At Lawrence Berkeley National Laboratory, various compact neutron generators based on D-D or D-T fusion reactions are being developed. The earlier theoretical studies of the D-D or D-T fusion reaction based neutron generators have shown that the optimal moderator and reflector configuration for brain tumor BNCT can be created. In this work, the applicability of 2.5 MeV neutrons for liver tumor BNCT application was studied. The optimal neutron energy for external liver treatments is not known. Neutron beams of different energies (1eV < E < 100 keV) were simulated and the dose distribution in the liver was calculated with the MCNP simulation code. In order to obtain the optimal neutron energy spectrum with the D-D neutrons, various moderator designs were performed using MCNP simulations. In this article the neutron spectrum and the optimized beam shaping assembly for liver tumor treatments is presented.
4. Enhanced blood boron concentration estimation for BPA-F mediated BNCT
Energy Technology Data Exchange (ETDEWEB)
Kortesniemi, M. E-mail: [email protected]; Seppaelae, T.; Auterinen, I.; Savolainen, S
2004-11-01
The blood boron concentration regulates directly the BNCT irradiation time in which the prescribed dose to the patient is delivered. Therefore a proper estimation of the blood boron concentration for the treatment field based on the measured blood samples before irradiation is required. The bi-exponential model fit using Levenberg-Marquardt method was implemented for this purpose to provide the blood boron concentration estimates directly to the treatment data flow during the BNCT procedure. The harmonic mean bi-exponential decay half-lives of the studied patient data (n=28) were 15{+-}8 and 320{+-}70 min for the faster and slower half-life. The model uncertainty (n=28) was reasonably low, 0.7{+-}0.1 {mu}g/g (about 5%). The implemented algorithm provides a robust method for temporal blood boron concentration estimation for BPA-F mediated BNCT. Utilization of the infusion data improves the reliability of the estimate. The overall data flow during the treatment fulfills the practical requirements concerning the BNCT procedure.
5. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors
OpenAIRE
Samia de Freitas Brandao; Tarcisio Passos Ribeiro de Campos
2013-01-01
Objective Comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and Methods Simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted int...
6. An analysing of heat treatment process planning
Directory of Open Access Journals (Sweden)
B. Smoljan
2007-01-01
Full Text Available Purpose: Process planning of heat treatment has been investigated. The established approach of heat treatingprocess planning is suitable for effective integration of heat treatment in computer added manufacturing.Design/methodology/approach: Process plan of heat treating process has been established based on fundamentalprocess planning principals. The heat treatment was treated in the same as other manufacture processes.Findings: The general approach for process planning of heat treatment processes has been established. Heattreatment processes have to be designed into operations and sub-operations with the same principles that are alsovalid for other manufacturing processes.Research limitations/implications: The further research should be focused on development of methods for thebetter application of achieved results.Practical implications: This way of heat treatment process planning is more appropriate for integral trends ofmanufacturing, i.e., with the trend of introducing the modern systems in all parts of industrial manufacturing.Originality/value: The global approach of process planning of heat treatment processes was established andbetter unification with other manufacturing processes was achieved.
7. INEL BNCT Program: Volume 5, No. 9
Energy Technology Data Exchange (ETDEWEB)
Ackermann, A.L. (ed.)
1991-01-01
This Bulletin presents a summary of accomplishments and highlights of the Idaho National Engineering Laboratory's (INEL) Boron Neutron Capture Therapy (BNCT) Program for September 1991. This bulletin includes information on the brain tumor and melanoma research programs, Power Burst Facility (PBF) technical support and modifications, PBF operations, and updates to the animal data charts.
8. Training Psychotherapists in Hierarchical Treatment Planning
OpenAIRE
MAKOVER, RICHARD B.
1992-01-01
Treatment planning is a central and persistent challenge in psychotherapy. This paper outlines a four-level planning hierarchy that encourages the therapist to conceptualize a desired overall outcome (the "aim") that can be realized through subsidiary objectives (the "goals"). The "strategies" by which goals are pursued and the "tactics" that carry out those strategies are subordinate and instrumental elements of the treatment process. Greater emphasis on this type of ...
9. Normalisation: ROI optimal treatment planning - SNDH pattern
International Nuclear Information System (INIS)
Dose precision maximally to the target / ROI (Region of Interest), taking care of tolerance dose of normal tissue is the aim of ideal treatment planning. This goal is achieved with advanced modalities such as, micro MLC, simulator and 3-dimensional treatment planning system. But SNDH PATTERN uses minimum available resources as, ALCYON II Telecobalt unit, CT Scan, MULTIDATA 2-dimensional treatment planning system to their maximum utility and reaches to the required precision, same as that with advance modalities. Among the number of parameters used, 'NORMALISATION TO THE ROI' will achieve the aim of the treatment planning effectively. This is dealing with an example of canal of esophagus modified treatment planning based on SNDH pattern. Results are attractive and self explanatory. By implementing SNDH pattern, the QUALITY INDEX of treatment plan will reach to greater than 90%, with substantial reduction in dose to the vital organs. Aim is to utilize the minimum available resources efficiently to achieve highest possible precision for delivering homogenous dose to ROI while taking care of tolerance dose to vital organs
10. Synthesis and evaluation of boron folates for Boron-Neutron-Capture-Therapy (BNCT)
Energy Technology Data Exchange (ETDEWEB)
Kettenbach, Kathrin; Schieferstein, Hanno; Grunewald, Catrin; Hampel, Gabriele; Schuetz, Christian L. [Mainz Univ. (Germany). Inst. of Nuclear Chemistry; Iffland, Dorothee; Bings, Nicolas H. [Mainz Univ. (Germany). Inst. of Inorganic Chemistry and Analytical Chemistry; Reffert, Laura M. [Hannover Medical School (Germany). Radiopharmaceutical Chemistry; Ross, Tobias L. [Mainz Univ. (Germany). Inst. of Nuclear Chemistry; Hannover Medical School (Germany). Radiopharmaceutical Chemistry
2015-07-01
Boron neutron capture therapy (BNCT) employs {sup 10}B-pharmaceuticals administered for the treatment of malignancies, and subsequently irradiated with thermal neutrons. So far, clinical established pharmaceuticals like boron phenylalanine (BPA) or sodium boron mercaptate (BSH) use imperfect (BPA) or passive (BSH) targeting for accumulation at target sites. Due to the need of a selective transportation of boron drugs into cancer cells and sparing healthy tissues, we combined the BNCT approach with the specific and effective folate receptor (FR) targeting concept. The FR is overexpressed on many human carcinomas and provides a selective and specific target for molecular imaging as well as for tumor therapy. We synthesized and characterized a carborane-folate as well as a BSH-folate to study their in vitro characteristics and their potential as new boron-carriers for BNCT. Uptake studies were carried out using human KB cells showing a significant increase of the boron content in cells and demonstrating the successful combination of active FR-targeting and BNCT.
11. BNCT-Project at the Finnish TRIGA Reactor
International Nuclear Information System (INIS)
An epithermal neutron irradiation station for the Boron Neutron Capture Therapy (BNCT) will be constructed in the thermal column of the Finnish Triga reactor. The first target of the BNCT at FiR 1 is the treatment of malignant brain tumors. The epithermal neutrons have the capability to penetrate deep into the brain tissue thermalizing at the same time. The thermal neutrons are captured by 10B-nuclei situated ideally in the tumor cells only and thus the reaction products destroy selectively only the tumor cells. The graphite filling of the thermal column will be replaced by a special moderator material: Al+AlF3. The moderator material and its thickness has been chosen so that the system produces as much as possible epithermal neutrons with low fast neutron and gamma contamination. Both fast neutrons and gamma radiation are harmful for the patient. To reduce the gamma radiation there is a lead-bismuth gamma shield at the outer end of the moderator block. In spite of the low power (250 kW) of the reactor the needed epithermal neutron dose to destroy the tumor will be accumulated in a reasonable time e.g. 0.5 to 1.5 h. This is possible because of the rather short distance between the reactor core and the irradiation target. (author)
12. Emergency Planning for Municipal Wastewater Treatment Facilities.
Science.gov (United States)
Lemon, R. A.; And Others
This manual for the development of emergency operating plans for municipal wastewater treatment systems was compiled using information provided by over two hundred municipal treatment systems. It covers emergencies caused by natural disasters, civil disorders and strikes, faulty maintenance, negligent operation, and accidents. The effects of such…
13. A colorimetric determination of boron in biological sample for boron neutron capture therapy (BNCT)
International Nuclear Information System (INIS)
The boron neutron capture therapy (BNCT) has shown better prognosis in the treatment of glyemas and gluoblastomas grade III and IV than other therapies. During the treatment the levels of Na210B12H11SH must be known in several compartiments of the organism and with this purpose the method of colorimetric determination of boron using curcumine was established. This method is simple, reprodutible and adequate sensitivity for this control. (author)
14. Investigating a multi-purpose target for electron linac based photoneutron sources for BNCT of deep-seated tumors
Energy Technology Data Exchange (ETDEWEB)
Masoudi, S. Farhad, E-mail: [email protected]; Rasouli, Fatemeh S.
2015-08-01
Recent studies in BNCT have focused on investigating appropriate neutron sources as alternatives for nuclear reactors. As the most prominent facilities, the electron linac based photoneutron sources benefit from two consecutive reactions, (e, γ) and (γ, n). The photoneutron sources designed so far are composed of bipartite targets which involve practical problems and are far from the objective of achieving an optimized neutron source. This simulation study deals with designing a compact, optimized, and geometrically simple target for a photoneutron source based on an electron linac. Based on a set of MCNPX simulations, tungsten is found to have the potential of utilizing as both photon converter and photoneutron target. Besides, it is shown that an optimized dimension for such a target slows-down the produced neutrons toward the desired energy range while keeping them economy, which makes achieving the recommended criteria for BNCT of deep-tumors more available. This multi-purpose target does not involve complicated designing, and can be considered as a significant step toward finding application of photoneutron sources for in-hospital treatments. In order to shape the neutron beam emitted from such a target, the beam is planned to pass through an optimized arrangement of materials composed of moderators, filters, reflector, and collimator. By assessment with the recommended in-air parameters, it is shown that the designed beam provides high intensity of desired neutrons, as well as low background contamination. The last section of this study is devoted to investigate the performance of the resultant beam in deep tissue. A typical simulated liver tumor, located within a phantom of human body, was subjected to the irradiation of the designed spectrum. The dosimetric results, including evaluated depth-dose curves and carried out in-phantom parameters show that the proposed configuration establishes acceptable agreement between the appropriate neutron intensity, and
15. Three-dimensional teletherapy treatment planning
International Nuclear Information System (INIS)
This thesis deals with physical/mathematical backgrounds of computerized teletherapy treatment planning. The subjects discussed in this thesis can be subdivided into three main categories: a) Three-dimensional treatment planning. A method is evaluated which can be used for the purpose of simulation and optimization of dose distributions in three dimensions. b) The use of Computed Tomography. The use of patient information obtained from Computed Tomography for the purpose of dose computations is evaluated. c) Dose computational models for photon- and electron beams. Models are evaluated which provide information regarding the way in which the radiation dose is distributed in the patient (viz. is absorbed and/or dispersed). (Auth.)
CERN Document Server
Chapman, J Donald
2015-01-01
Understand Quantitative Radiobiology from a Radiation Biophysics PerspectiveIn the field of radiobiology, the linear-quadratic (LQ) equation has become the standard for defining radiation-induced cell killing. Radiotherapy Treatment Planning: Linear-Quadratic Radiobiology describes tumor cell inactivation from a radiation physics perspective and offers appropriate LQ parameters for modeling tumor and normal tissue responses.Explore the Latest Cell Killing Numbers for Defining Iso-Effective Cancer TreatmentsThe book compil
17. Treatment planning for volumetric modulated arc therapy
Energy Technology Data Exchange (ETDEWEB)
Bedford, James L. [Joint Department of Physics, Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT (United Kingdom)
2009-11-15
Purpose: Volumetric modulated arc therapy (VMAT) is a specific type of intensity-modulated radiation therapy (IMRT) in which the gantry speed, multileaf collimator (MLC) leaf position, and dose rate vary continuously during delivery. A treatment planning system for VMAT is presented. Methods: Arc control points are created uniformly throughout one or more arcs. An iterative least-squares algorithm is used to generate a fluence profile at every control point. The control points are then grouped and all of the control points in a given group are used to approximate the fluence profiles. A direct-aperture optimization is then used to improve the solution, taking into account the allowed range of leaf motion of the MLC. Dose is calculated using a fast convolution algorithm and the motion between control points is approximated by 100 interpolated dose calculation points. The method has been applied to five cases, consisting of lung, rectum, prostate and seminal vesicles, prostate and pelvic lymph nodes, and head and neck. The resulting plans have been compared with segmental (step-and-shoot) IMRT and delivered and verified on an Elekta Synergy to ensure practicality. Results: For the lung, prostate and seminal vesicles, and rectum cases, VMAT provides a plan of similar quality to segmental IMRT but with faster delivery by up to a factor of 4. For the prostate and pelvic nodes and head-and-neck cases, the critical structure doses are reduced with VMAT, both of these cases having a longer delivery time than IMRT. The plans in general verify successfully, although the agreement between planned and measured doses is not very close for the more complex cases, particularly the head-and-neck case. Conclusions: Depending upon the emphasis in the treatment planning, VMAT provides treatment plans which are higher in quality and/or faster to deliver than IMRT. The scheme described has been successfully introduced into clinical use.
18. INEL BNCT Research Program, September--October 1992
Energy Technology Data Exchange (ETDEWEB)
Venhuizen, J.R.
1992-12-01
This report presents summaries for two months of current research of the Idaho National Engineering Laboratory (INEL) Boron Neutron Capture Therapy (BNCT) Program. Information is presented on development and murine screening experiments of low-density lipoprotain. carboranyl alanine, and liposome boron containing compounds. Pituitary tumor call culture studies are described. Drug stability, pharmacology and toxicity evaluation of borocaptate sodium (BSH) and boronophonylalanine (BPA) are described. Treatment protocol development via the large animal (canine) model studies and physiological response evaluation in rats are discussed. Supporting technology development and technical support activities for boron drug biochemistry and purity, analytical and measurement dosimetry, and noninvasive boron quantification activities are included for the current time period. Current publications for the two months are listed.
19. INEL BNCT Research Program, May/June 1992
International Nuclear Information System (INIS)
This report presents summaries for two months of current research of the Idaho National Engineering Laboratory (INEL) Boron Neutron Capture Therapy (BNCT) Program. Information is presented on development and murine screening experiments of low-density lipoprotein, carboranyl alanine, and liposome boron containing compounds. Pituitary tumor cell culture studies are described. Drug stability, pharmacology and toxicity evaluation of borocaptate sodium (BSH) and boronophenylaianine (IBPA) are described. Treatment protocol development via the large animal (canine) model studies and physiological response evaluation in rats are discussed. Supporting technology development and technical support activities for boron drug biochemistry and purity, analytical and measurement dosimetry, and noninvasive boron quantification activities are included for the current time period. Current publications for the two months are listed
20. INEL BNCT Research Program, January/February 1993
International Nuclear Information System (INIS)
This report presents summaries for two months of current research of the Idaho National Engineering Laboratory (INEL) Boron Neutron Capture Therapy (BNCT) Program. Information is presented on development and murine screening experiments of low-density lipoprotein, carboranyl alanine, and liposome boron containing compounds. Pituitary tumor cell culture studies are described. Drug stability, pharmacology and toxicity evaluation of borocaptate sodium (BSH) and boronophenylaianine (BPA) are described. Treatment protocol development via the large animal (canine) model studies and physiological response evaluation in rats are discussed. Supporting technology development and technical support activities for boron drug biochemistry and purity, analytical and measurement dosimetry, and noninvasive boron quantification activities are included for the current time period. Current publications for the two months are listed
1. INEL BNCT research program, July--August 1992
Energy Technology Data Exchange (ETDEWEB)
Venhuizen, J.R.
1992-10-01
This report presents summaries for two months of current research of the Idaho National Engineering Laboratory (INEL) Boron Neutron Capture Therapy (BNCT) Program. Information is presented on development and murine screening experiments of low-density lipoprotein, carboranyl alanine, and liposome boron containing compounds. Pituitary tumor cell culture studies are described. Drug stability, pharmacology and toxicity evaluation of borocaptate sodium (BSH) and boronophenylalanine (BPA) are described. Treatment protocol development via the large animal (canine) model studies and physiological response evaluation in rats are discussed. Supporting technology development and technical support activities for boron drug biochemistry and purity, analytical and measurement dosimetry, and noninvasive boron quantification activities are included for the current time period. Current publications for the two months are listed.
2. INEL BNCT Research Program, March/April 1992
Energy Technology Data Exchange (ETDEWEB)
Venhuizen, J.R.
1992-09-01
This report presents summaries for two months of current research for the Idaho National Engineering Laboratory (INEL) Boron Neutron Capture Therapy (BNCT) Program. Information is presented on development and murino screening experiments of low-density lipoprotein, carboranyl alanine, and liposome boron containing compounds. Pituitary tumor call culture studies are described. Drug stability, pharmacology and toxicity evaluation of borocaptate sodium (BSH) and boronopheoylalanine (BPA) are described. Treatment protocol development via the large animal (canine) model studies and physiological response evaluation in rats are discussed. Supporting technology development and technical support activities for boron drug biochemistry and purity, analytical and measurement dosimetry, and noninvasive boron quantification activities are included for the current time period. Current publications for the two months are listed.
3. INEL BNCT Research Program, May/June 1992
Energy Technology Data Exchange (ETDEWEB)
Venhuizen, J.R.
1992-09-01
This report presents summaries for two months of current research of the Idaho National Engineering Laboratory (INEL) Boron Neutron Capture Therapy (BNCT) Program. Information is presented on development and murine screening experiments of low-density lipoprotein, carboranyl alanine, and liposome boron containing compounds. Pituitary tumor cell culture studies are described. Drug stability, pharmacology and toxicity evaluation of borocaptate sodium (BSH) and boronophenylaianine (IBPA) are described. Treatment protocol development via the large animal (canine) model studies and physiological response evaluation in rats are discussed. Supporting technology development and technical support activities for boron drug biochemistry and purity, analytical and measurement dosimetry, and noninvasive boron quantification activities are included for the current time period. Current publications for the two months are listed.
4. INEL BNCT Research Program, September--October 1992
International Nuclear Information System (INIS)
This report presents summaries for two months of current research of the Idaho National Engineering Laboratory (INEL) Boron Neutron Capture Therapy (BNCT) Program. Information is presented on development and murine screening experiments of low-density lipoprotain. carboranyl alanine, and liposome boron containing compounds. Pituitary tumor call culture studies are described. Drug stability, pharmacology and toxicity evaluation of borocaptate sodium (BSH) and boronophonylalanine (BPA) are described. Treatment protocol development via the large animal (canine) model studies and physiological response evaluation in rats are discussed. Supporting technology development and technical support activities for boron drug biochemistry and purity, analytical and measurement dosimetry, and noninvasive boron quantification activities are included for the current time period. Current publications for the two months are listed
5. FiR 1 reactor in service for boron neutron capture therapy (BNCT) and isotope production
International Nuclear Information System (INIS)
The FiR 1 reactor, a 250 kW Triga reactor, has been in operation since 1962. The main purpose for the existence of the reactor is now the Boron Neutron Capture Therapy (BNCT), but FiR 1 has also an important national role in providing local enterprises and research institutions in the fields of industrial measurements, pharmaceuticals, electronics etc. with isotope production and activation analysis services. In the 1990's a BNCT treatment facility was built at the FiR 1 reactor located at Technical Research Centre of Finland. A special new neutron moderator material FluentalTM (Al+AlF3+Li) developed at VTT ensures the superior quality of the neutron beam. Also the treatment environment is of world top quality after a major renovation of the whole reactor building in 1997. Recently the lithiated polyethylene neutron shielding of the beam aperture was modified to ease the positioning of the patient close to the beam aperture. Increasing the reactor power to 500 kW would allow positioning of the patient further away from the beam aperture. Possibilities to accomplish a safety analysis for this is currently under considerations. Over thirty patients have been treated at FiR 1 since May 1999, when the license for patient treatment was granted to the responsible BNCT treatment organization, Boneca Corporation. Currently three clinical trial protocols for tumours in the brain as well as in the head and neck region are recruiting patients. (author)
6. A toolkit for epithermal neutron beam characterisation in BNCT.
Science.gov (United States)
Auterinen, Iiro; Serén, Tom; Uusi-Simola, Jouni; Kosunen, Antti; Savolainen, Sauli
2004-01-01
Methods for dosimetry of epithermal neutron beams used in boron neutron capture therapy (BNCT) have been developed and utilised within the Finnish BNCT project as well as within a European project for a code of practise for the dosimetry of BNCT. One outcome has been a travelling toolkit for BNCT dosimetry. It consists of activation detectors and ionisation chambers. The free-beam neutron spectrum is measured with a set of activation foils of different isotopes irradiated both in a Cd-capsule and without it. Neutron flux (thermal and epithermal) distribution in phantoms is measured using activation of Mn and Au foils, and Cu wire. Ionisation chamber (IC) measurements are performed both in-free-beam and in-phantom for determination of the neutron and gamma dose components. This toolkit has also been used at other BNCT facilities in Europe, the USA, Argentina and Japan.
7. Cost-Effective Fuel Treatment Planning
Science.gov (United States)
Kreitler, J.; Thompson, M.; Vaillant, N.
2014-12-01
The cost of fighting large wildland fires in the western United States has grown dramatically over the past decade. This trend will likely continue with growth of the WUI into fire prone ecosystems, dangerous fuel conditions from decades of fire suppression, and a potentially increasing effect from prolonged drought and climate change. Fuel treatments are often considered the primary pre-fire mechanism to reduce the exposure of values at risk to wildland fire, and a growing suite of fire models and tools are employed to prioritize where treatments could mitigate wildland fire damages. Assessments using the likelihood and consequence of fire are critical because funds are insufficient to reduce risk on all lands needing treatment, therefore prioritization is required to maximize the effectiveness of fuel treatment budgets. Cost-effectiveness, doing the most good per dollar, would seem to be an important fuel treatment metric, yet studies or plans that prioritize fuel treatments using costs or cost-effectiveness measures are absent from the literature. Therefore, to explore the effect of using costs in fuel treatment planning we test four prioritization algorithms designed to reduce risk in a case study examining fuel treatments on the Sisters Ranger District of central Oregon. For benefits we model sediment retention and standing biomass, and measure the effectiveness of each algorithm by comparing the differences among treatment and no treat alternative scenarios. Our objective is to maximize the averted loss of net benefits subject to a representative fuel treatment budget. We model costs across the study landscape using the My Fuel Treatment Planner software, tree list data, local mill prices, and GIS-measured site characteristics. We use fire simulations to generate burn probabilities, and estimate fire intensity as conditional flame length at each pixel. Two prioritization algorithms target treatments based on cost-effectiveness and show improvements over those
8. 64: 3-D treatment planning. 4
International Nuclear Information System (INIS)
A full function brachytherapy treatment planning program has been developed as part of the 3-D treatment planning system U-MPlan. This program integrates more conventional brachytherapy planning with multi-modality imaging. As a result, source locations can be derived from and displayed over a variety of images including CT, MR, and digitized radiographs. Derived three-dimensional anatomical data can be used to help in designing and evaluating dose distributions. Cross-sectional calculational planes can be defined relative to the anatomy or modified to be oriented with respect to the implant symmetry. Special utilities are provided for designing stereotactic brain implants. Calculational results can be viewed both two- and three-dimensionally relative to axonometric views of image cross-sections and derived anatomical structures. Isodose surfaces can be generated and displayed as well as dose displays across anatomical surfaces. Dose-volume histograms and composite or subtracted plans can be used to evaluate and/or compare rival plans. 5 refs.; 4 figs
9. Use of fluorine-18-BPA PET images and image registration to enhance radiation treatment planning for boron neutron capture therapy
Science.gov (United States)
The Monte-Carlo based simulation environment for radiation therapy (SERA) software is used to simulate the dose administered to a patient undergoing boron neutron capture therapy (BNCT). Point sampling of tumor tissue results in an estimate of a uniform boron concentration scaling factor of 3.5. Under conventional treatment protocols, this factor is used to scale the boron component of the dose linearly and homogenously within the tumor and target volumes. The average dose to the tumor cells by such a method could be improved by better methods of quantifying the in-vivo 10B biodistribution. A better method includes radiolabeling para-Boronophenylalanine (p-BPA) with 18F and imaging the pharmaceutical using positron emission tomography (PET). This biodistribution of 18F-BPA can then be used to better predict the average dose delivered to the tumor regions. This work uses registered 18F-BPA PET images to incorporate the in-vivo boron biodistribution within current treatment planning. The registered 18F-BPA PET images are then coupled in a new computer software, PET2MRI.m, to linearly scale the boron component of the dose. A qualititative and quantitative assessment of the dose contours is presented using the two approaches. Tumor volume, tumor axial extent, and target locations are compared between using MRI or PET images to define the tumor volume. In addition, peak-to-normal brain value at tumor axial center is determined for pre and post surgery patients using 18F-BPA PET images. The differences noted between the registered GBM tumor volumes (range: 34.04--136.36%), tumor axial extent (range: 20--150%), and the beam target location (1.27--4.29 cm) are significantly different. The peak-to-normal brain values are also determined at the tumor axial center using the 18F-BPA PET images. The peak-to-normal brain values using the last frame of the pre-surgery study for the GBM patients ranged from 2.05--3.4. For post surgery time weighted PET data, the peak
10. Cationized gelatin-HVJ envelope with sodium borocaptate improved the BNCT efficacy for liver tumors in vivo
International Nuclear Information System (INIS)
Boron neutron capture therapy (BNCT) is a cell-selective radiation therapy that uses the alpha particles and lithium nuclei produced by the boron neutron capture reaction. BNCT is a relatively safe tool for treating multiple or diffuse malignant tumors with little injury to normal tissue. The success or failure of BNCT depends upon the 10B compound accumulation within tumor cells and the proximity of the tumor cells to the body surface. To extend the therapeutic use of BNCT from surface tumors to visceral tumors will require 10B compounds that accumulate strongly in tumor cells without significant accumulation in normal cells, and an appropriate delivery method for deeper tissues. Hemagglutinating Virus of Japan Envelope (HVJ-E) is used as a vehicle for gene delivery because of its high ability to fuse with cells. However, its strong hemagglutination activity makes HVJ-E unsuitable for systemic administration. In this study, we developed a novel vector for 10B (sodium borocaptate: BSH) delivery using HVJ-E and cationized gelatin for treating multiple liver tumors with BNCT without severe adverse events. We developed cationized gelatin conjugate HVJ-E combined with BSH (CG-HVJ-E-BSH), and evaluated its characteristics (toxicity, affinity for tumor cells, accumulation and retention in tumor cells, boron-carrying capacity to multiple liver tumors in vivo, and bio-distribution) and effectiveness in BNCT therapy in a murine model of multiple liver tumors. CG-HVJ-E reduced hemagglutination activity by half and was significantly less toxic in mice than HVJ-E. Higher 10B concentrations in murine osteosarcoma cells (LM8G5) were achieved with CG-HVJ-E-BSH than with BSH. When administered into mice bearing multiple LM8G5 liver tumors, the tumor/normal liver ratios of CG-HVJ-E-BSH were significantly higher than those of BSH for the first 48 hours (p < 0.05). In suppressing the spread of tumor cells in mice, BNCT treatment was as effective with CG-HVJ-E-BSH as with BSH
11. Tumor development in field-cancerized tissue is inhibited by a double application of Boron neutron capture therapy (BNCT) without exceeding radio-tolerance
International Nuclear Information System (INIS)
Introduction: BNCT is based on the capture reaction between boron, selectively targeted to tumor tissue, and thermal neutrons which gives rise to lethal, short-range high linear energy transfer particles that selectively damage tumor tissue, sparing normal tissue. We previously evidenced a remarkable therapeutic success of a 'single' application of boron neutron capture therapy (BNCT) mediated by boronophenylalanine (BPA), GB-1(Na210B10H10) or (GB-10+BPA) to treat hamster cheek pouch tumors with no normal tissue radiotoxicity. Based on these results, we developed a model of precancerous tissue in the hamster cheek pouch for long-term studies. Employing this model we evaluated the long-term potential inhibitory effect on the development of second primary tumors from precancerous tissue and eventual radiotoxicity of a single application of BNCT mediated by BPA, GB-10 or (GB-10+BPA), in the RA-6. The clinical rationale of this study was to search for a BNCT protocol that is therapeutic for tumor, not radio-toxic for the normal tissue that lies in the neutron beam path, and exerts the desired inhibitory effect on the development of second primary tumors, without exceeding the radio-tolerance of precancerous tissue, the dose limiting tissue in this case. Second primary tumors that arise in precancerous tissue (also called locoregional recurrences) are a frequent cause of therapeutic failure in head and neck tumors. Aim: Evaluate the radiotoxicity and inhibitory effect of a 'double' application of the same BNCT protocols that were proved therapeutically successful for tumor and precancerous tissue, with a long term follow up (8 months). A 'double' application of BNCT is a potentially useful strategy for the treatment of tumors, in particular the larger ones, but the cost in terms of side-effects in dose-limiting tissues might preclude its application and requires cautious evaluation. Materials and methods: We performed a double application of 1) BPA-BNCT; 2) (GB- 10+BPA)-BNCT
12. Automatic liver contouring for radiotherapy treatment planning
Science.gov (United States)
Li, Dengwang; Liu, Li; Kapp, Daniel S.; Xing, Lei
2015-09-01
To develop automatic and efficient liver contouring software for planning 3D-CT and four-dimensional computed tomography (4D-CT) for application in clinical radiation therapy treatment planning systems. The algorithm comprises three steps for overcoming the challenge of similar intensities between the liver region and its surrounding tissues. First, the total variation model with the L1 norm (TV-L1), which has the characteristic of multi-scale decomposition and an edge-preserving property, is used for removing the surrounding muscles and tissues. Second, an improved level set model that contains both global and local energy functions is utilized to extract liver contour information sequentially. In the global energy function, the local correlation coefficient (LCC) is constructed based on the gray level co-occurrence matrix both of the initial liver region and the background region. The LCC can calculate the correlation of a pixel with the foreground and background regions, respectively. The LCC is combined with intensity distribution models to classify pixels during the evolutionary process of the level set based method. The obtained liver contour is used as the candidate liver region for the following step. In the third step, voxel-based texture characterization is employed for refining the liver region and obtaining the final liver contours. The proposed method was validated based on the planning CT images of a group of 25 patients undergoing radiation therapy treatment planning. These included ten lung cancer patients with normal appearing livers and ten patients with hepatocellular carcinoma or liver metastases. The method was also tested on abdominal 4D-CT images of a group of five patients with hepatocellular carcinoma or liver metastases. The false positive volume percentage, the false negative volume percentage, and the dice similarity coefficient between liver contours obtained by a developed algorithm and a current standard delineated by the expert group
13. Towards the final BSA modeling for the accelerator-driven BNCT facility at INFN LNL
Energy Technology Data Exchange (ETDEWEB)
Ceballos, C. [Centro de Aplicaciones Tecnlogicas y Desarrollo Nuclear, 5ta y30, Miramar, Playa, Ciudad Habana (Cuba); Esposito, J., E-mail: [email protected] [INFN, Laboratori Nazionali di Legnaro (LNL), via dell' Universita, 2, I-35020 Legnaro (PD) (Italy); Agosteo, S. [Politecnico di Milano, Dipartimento di Energia, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)] [INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Colautti, P.; Conte, V.; Moro, D. [INFN, Laboratori Nazionali di Legnaro (LNL), via dell' Universita, 2, I-35020 Legnaro (PD) (Italy); Pola, A. [Politecnico di Milano, Dipartimento di Energia, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)] [INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy)
2011-12-15
Some remarkable advances have been made in the last years on the SPES-BNCT project of the Istituto Nazionale di Fisica Nucleare (INFN) towards the development of the accelerator-driven thermal neutron beam facility at the Legnaro National Laboratories (LNL), aimed at the BNCT experimental treatment of extended skin melanoma. The compact neutron source will be produced via the {sup 9}Be(p,xn) reactions using the 5 MeV, 30 mA beam driven by the RFQ accelerator, whose modules construction has been recently completed, into a thick beryllium target prototype already available. The Beam Shaping Assembly (BSA) final modeling, using both neutron converter and the new, detailed, Be(p,xn) neutron yield spectra at 5 MeV energy recently measured at the CN Van de Graaff accelerator at LNL, is summarized here.
14. INEL BNCT Research Program annual report, 1992
International Nuclear Information System (INIS)
This report is a summary of the progress and research produced for the Idaho National Engineering Laboratory Boron Neutron Capture Therapy (BNCT) Research Program for calendar year 1992. Contributions from all the principal investigators about their individual projects are included, specifically, chemistry (pituitary tumor targeting compounds, boron drug development including liposomes, lipoproteins, and carboranylalanine derivatives), pharmacology (murine screenings, toxicity testing, inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis of biological samples), physics (radiation dosimetry software, neutron beam and filter design, neutron beam measurement dosimetry), and radiation biology (small and large animal models tissue studies and efficacy studies). Information on the potential toxicity of borocaptate sodium and boronophenylalanine is presented, results of 21 spontaneous-tumor-bearing dogs that have been treated with BNCT at the Brookhaven National Laboratory (BNL) Medical Research Reactor (BMRR) are discussed, and predictions for an epithermal-neutron beam at the Georgia Tech Research Reactor (GTRR) are shown. Cellular-level boron detection and localization by secondary ion mass spectrometry, sputter-initiated resonance ionization spectroscopy, low atomization resonance ionization spectroscopy, and alpha track are presented. Boron detection by ICP-AES is discussed in detail. Several boron carrying drugs exhibiting good tumor uptake are described. Significant progress in the potential of treating pituitary tumors with BNCT is presented. Measurement of the epithermal-neutron flux at BNL and comparison to predictions are shown. Calculations comparing the GTRR and BMRR epithermal-neutron beams are also presented. Individual progress reports described herein are separately abstracted and indexed for the database
15. INEL BNCT Research Program annual report, 1992
Energy Technology Data Exchange (ETDEWEB)
Venhuizen, J.R. [ed.
1993-05-01
This report is a summary of the progress and research produced for the Idaho National Engineering Laboratory Boron Neutron Capture Therapy (BNCT) Research Program for calendar year 1992. Contributions from all the principal investigators about their individual projects are included, specifically, chemistry (pituitary tumor targeting compounds, boron drug development including liposomes, lipoproteins, and carboranylalanine derivatives), pharmacology (murine screenings, toxicity testing, inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis of biological samples), physics (radiation dosimetry software, neutron beam and filter design, neutron beam measurement dosimetry), and radiation biology (small and large animal models tissue studies and efficacy studies). Information on the potential toxicity of borocaptate sodium and boronophenylalanine is presented, results of 21 spontaneous-tumor-bearing dogs that have been treated with BNCT at the Brookhaven National Laboratory (BNL) Medical Research Reactor (BMRR) are discussed, and predictions for an epithermal-neutron beam at the Georgia Tech Research Reactor (GTRR) are shown. Cellular-level boron detection and localization by secondary ion mass spectrometry, sputter-initiated resonance ionization spectroscopy, low atomization resonance ionization spectroscopy, and alpha track are presented. Boron detection by ICP-AES is discussed in detail. Several boron carrying drugs exhibiting good tumor uptake are described. Significant progress in the potential of treating pituitary tumors with BNCT is presented. Measurement of the epithermal-neutron flux at BNL and comparison to predictions are shown. Calculations comparing the GTRR and BMRR epithermal-neutron beams are also presented. Individual progress reports described herein are separately abstracted and indexed for the database.
16. Electron Density Calibration for Radiotherapy Treatment Planning
Science.gov (United States)
Herrera-Martínez, F.; Rodríguez-Villafuerte, M.; Martínez-Dávalos, A.; Ruiz-Trejo, C.; Celis-López, M. A.; Lárraga-Gutiérrez, J. M.; García-Garduño, A.
2006-09-01
Computed tomography (CT) images are used as basic input data for most modern radiosurgery treatment planning systems (TPS). CT data not only provide anatomic information to delineate target volumes, but also allow the introduction of corrections for tissue inhomogeneities into dose calculations during the treatment planning procedure. These corrections involve the determination of a relationship between tissue electron density (ρe) and their corresponding Hounsfield Units (HU). In this work, an elemental analysis of different commercial tissue equivalent materials using Scanning Electron Microscopy was carried out to characterize their chemical composition. The tissue equivalent materials were chosen to ensure a large range of ρe to be included in the CT scanner calibration. A phantom was designed and constructed with these materials to simulate the size of a human head.
DEFF Research Database (Denmark)
Cronholm, Rickard
for commissioning of a Monte Carlo model of a medical linear accelerator, ensuring agreement with measurements within 1% for a range of situations, is presented. The resulting Monte Carlo model was validated against measurements for a wider range of situations, including small field output factors, and agreement...... modulating the intensity of the field during the irradiation. The workflow described has the potential to fully model the dynamic delivery, including gantry rotation during irradiation, of modern radiotherapy. Three corner stones of Monte Carlo Treatment Planning are identified: Building, commissioning...... and validation of a Monte Carlo model of a medical linear accelerator (i), converting a CT scan of a patient to a Monte Carlo compliant phantom (ii) and translating the treatment plan parameters (including beam energy, angles of incidence, collimator settings etc) to a Monte Carlo input file (iii). A protocol...
18. Quality assurance for BNCT at nuclear facilities. A necessary burden or the unavoidable seal of approval
International Nuclear Information System (INIS)
The BNCT clinical trial at the HFR Petten is performed on a completely multi-national basis. The irradiation facility is located in one country (The Netherlands), is operated by an international team of experts under the leadership of a radiotherapist from another country (Germany) and treats patients coming from different European countries. In gaining the necessary approval, it became apparent, especially in the many discussions with the (Dutch) Health authorities that Quality Assurance (QA) would be and is a critical aspect. This is even more so, in the case of BNCT, where it was not only a (relatively) new experimental treatment (in 1996/97) about to be performed for the first time in Europe, but it was to be performed in a non-hospital environment and furthermore in a nuclear research reactor. It was necessary therefore to comply, as closely as possible, with similarly accepted practices in conventional radiotherapy. Despite QA being a sometimes burdensome task, this paper nevertheless raises the issue as to whether it is necessary or whether it is the seal of approval for BNCT as an acceptable mode of treatment in mainstream radiotherapy. (author)
International Nuclear Information System (INIS)
The aim of an oncological treatment is to eradicate the tumor without inducing unacceptable side effects. The optimization of a dose distribution with external beams requires the selection of the radiation type and energy, the number of fields, their sizes and incidence angles of the beams and then the possible use of wedges or compensating filters. The goal of optimal treatment planning is to provide maximum tumor killing while sparing normal tissues as much as possible. New, more sophisticated planning systems, based on three dimensional dose distribution calculations, require simplified data interpretation techniques. Dose volume histograms represent a convenient and useful tool to summarize dose distribution information through the entire volume of a given anatomic structure and to quickly highlight characteristics such as dose uniformity and hot and cold spots. It is difficult however to choose among competing histograms concerning different organs when they cross one another. This paper discusses the development of a computerized treatment planning system in which dose volume histograms are used to estimate tumor control and normal tissue complication probabilities
20. Treatment planning system for carbon ion radiotherapy
Energy Technology Data Exchange (ETDEWEB)
Koyama-Ito, Hiroko [National Inst. of Radiological Sciences, Chiba (Japan)
2002-06-01
This paper describes the treatment planning (TP) and its peripheral system for carbon ion therapy that has been developed and in clinical use in recent two years at our institution. A new treatment planning system which is FOCUS customized to our irradiation system will be launched in clinical use soon. A new DICOM based PACS has been developed and in use. Now MRI, PET images are ready to be utilized for patient definition with image fusion functionality of radiotherapy TP. We implemented the exchange functionality of TP data specified by RTOG 3D QA Center in FOCUS, Pinnacle3 and heavy ion TP. Target volume and normal structure contours and dose distributions are exchangeable. A database system of carbon ion therapy dedicated to analysis of therapy data has been designed and implemented. All accessible planning data and treatment records of more than 1000 patients treated for seven and half years have been archived. The system has a DICOM RT sever and a database for miscellaneous text data. Limited numbers of private attributes were introduced for ion therapy specific objects. On-line as well as manual registration along with edit functionalities is prepared. Standard web browser is used to search and retrieve information. A DICOM RT viewer has been developed to view and retrieve RT images, dose distributions and structure set. These system described above are all designed to conform to the up-to-date standards of radiation therapy so as to be bases of the future development of the therapy at our institution. (author)
1. Advanced Treatment Planning in Cancer Thermal Therapies
Institute of Scientific and Technical Information of China (English)
Theodoros SAMARAS; Esra NEUFELD; Niels KUSTER
2016-01-01
CEM43 thermal dose is a very common concept in thermal oncology. Thermal dose is the maximum amount of energy that can be transmitted during hyperthermia therapy conducted on temperature-sensitive tissue. Thermal dose is also the maximum value of local energy accumulation in human bodies, which can lead to tissue injury and pain. Thermal dose can also decrease the ifnishing temperature and reduce the energy to the tolerable range. There are two functions of the individualized hyperthermia treatment plan: it determines the setting and location that can realize the best tumor hyperthermia therapy; at the same time, it can decrease the effect of hyperthermia therapy on healthy tissues. There are four steps in the treatment plan of hyperthermia therapy for tumors: the ifrst step is to establish a three dimensional human body model and its corresponding an atomical structure that can be used in numerical algorithmvia medical imaging resources; the second step is to determine the volume of the electromagnetic energy accumulation. Based on the peculiarity of frequency and materials, even full-wave electromagnetic wave or quasi-static technique can be used to determine the tissue distribution. Evaluation of the therapy can be conducted based on thermal dose and the corresponding tissue damage model; the third step is to use Arrhenius model to provide direct evaluation of tissues in the thermal ablation zone, solidiifcation zone, as well as the necrotic area; the last step is the optimization of the treatment plan.
2. American brain tumor patients treated with BNCT in Japan
Energy Technology Data Exchange (ETDEWEB)
Laramore, G.E.; Griffin, B.R.; Spence, A.
1995-11-01
The purpose of this work is to establish and maintain a database for patients from the United States who have received BNCT in Japan for malignant gliomas of the brain. This database will serve as a resource for the DOE to aid in decisions relating to BNCT research in the United States, as well as assisting the design and implementation of clinical trials of BNCT for brain cancer patients in this country. The database will also serve as an information resource for patients with brain tumors and their families who are considering this form of therapy.
3. An accelerator-based epithermal photoneutron source for BNCT
Energy Technology Data Exchange (ETDEWEB)
Nigg, D.W.; Mitchell, H.E.; Harker, Y.D.; Yoon, W.Y. [and others
1995-11-01
Therapeutically-useful epithermal-neutron beams for BNCT are currently generated by nuclear reactors. Various accelerator-based neutron sources for BNCT have been proposed and some low intensity prototypes of such sources, generally featuring the use of proton beams and beryllium or lithium targets have been constructed. This paper describes an alternate approach to the realization of a clinically useful accelerator-based source of epithermal neutrons for BNCT that reconciles the often conflicting objectives of target cooling, neutron beam intensity, and neutron beam spectral purity via a two stage photoneutron production process.
4. Concept of a BNCT line with in-pool fission converter at MARIA reactor in Swierk
Science.gov (United States)
Pytel, Krzysztof; Andrzejewski, Krzysztof; Golnik, Natalia; Osko, Jakub
2009-01-01
BNCT facility in the Institute of Atomic Energy in Otwock-Swierk is under construction at the horizontal channel H2 of the research reactor MARIA. Measurements of the neutron energy spectrum performed at the front of the H2 experimental channel, have shown that flux of epithermal neutrons (above 10 keV) at the BNCT irradiation port was below 109 n cm-2 s-1 i.e. it was too low to be directly used for the BNCT treatment. Therefore, a fission converter will be placed between the reactor core and the periphery of the graphite reflector of MARIA reactor. The uranium converter will be powered by the densely packed EK-10 fuel elements with 10% enrichment. Preliminary calculations have shown that the total neutron flux in the converter will be about 1013 n cm-2 s-1 and flux of epithermal neutrons at the entrance to the filter/moderator of the beam will be about 2·1013 n cm-2 s-1.
5. Nevada Test Site Treatment Plan. Revision 2
Energy Technology Data Exchange (ETDEWEB)
NONE
1996-03-01
Treatment Plans (STPS) are required for facilities at which the US Department of Energy (DOE) or stores mixed waste, defined by the Federal Facility Compliance Act (FFCAct) as waste containing both a hazardous waste subject to the Resource Conservation and Recovery Act and a radioactive material subject to the Atomic Energy Act. On April 6, 1993, DOE published a Federal Register notice (58 FR 17875) describing its proposed process for developing the STPs in three phases including a Conceptual, a Draft, and a Proposed Site Treatment Plan (PSTP). All of the DOE Nevada Operations Office STP iterations have been developed with the state of Nevadas input. The options and schedules reflect a bottoms-up approach and have been evaluated for impacts on other DOE sites, as well as impacts to the overall DOE program. Changes may have occurred in the preferred option and associated schedules between the PSTP, which was submitted to the state of Nevada and US Environmental Protection Agency April 1995, and the Final STP (hereafter referred to as the STP) as treatment evaluations progressed. The STP includes changes that have occurred since the submittal of the PSTP as a result of state-to-state and DOE-to-state discussions.
6. Photographic-assisted diagnosis and treatment planning.
Science.gov (United States)
Goodlin, Ron
2011-04-01
The advent of digital photography allows the practitioner to show the patient the photographs immediately, to co-diagnose, and to work with the patient chairside or in a consult room while showing the patient some simple imaging techniques, such as whitening the teeth, making the teeth look longer, and showing the effects of orthodontics or veneers to get better alignment and other factors of smile design and esthetic dentistry. This article describes recommended digital dental photographic equipment, how to produce the standard series of diagnostic dental photographs, photographic assisted diagnosis and treatment planning including a discussion of anthropometrics and cephalometrics, and digital imaging techniques.
7. Present status of BNCT at Kyoto University Research Reactor Institute
International Nuclear Information System (INIS)
At Kyoto University Research Reactor Institute, we have two facilities for BNCT such as a reactor-based and an accelerator-based neutron source. In this article, we will present the characteristics overview of both facilities. (author)
8. Biodistribution of Boron compounds in an experimental model of liver metastases for Boron Neutron Capture (BNCT) Studies
International Nuclear Information System (INIS)
Boron Neutron Capture Therapy (BNCT) is a binary treatment modality that involves the selective accumulation of 10B carriers in tumors followed by irradiation with thermal or epithermal neutrons. The high linear energy transfer alpha particles and recoiling 7Li nuclei emitted during the capture of a thermal neutron by a 10B nucleus have a short range and a high biological effectiveness. Thus, BNCT would potentially target neoplastic tissue selectively. In previous studies we demonstrated the therapeutic efficacy of different BNCT protocols in an experimental model of oral cancer. More recently we performed experimental studies in normal rat liver that evidenced the feasibility of treating liver metastases employing a novel BNCT protocol proposed by JEC based on ex-situ treatment and partial liver auto-transplant. The aim of the present study was to perform biodistribution studies with different boron compounds and different administration protocols to determine the protocols that would be therapeutically useful in 'in vivo' BNCT studies at the RA-3 Nuclear Reactor in an experimental model of liver metastases in rats. Materials and Methods. A total of 70 BDIX rats (Charles River Lab., MA, USA) were inoculated in the liver with syngeneic colon cancer cells DH/DK12/TRb (ECACC, UK) to induce the development of subcapsular metastatic nodules. 15 days post-inoculation the animals were used for biodistribution studies. A total of 11 protocols were evaluated employing the boron compounds boronophenylalanine (BPA) and GB-10 (Na210B1-0H10), alone or combined employing different doses and administration routes. Tumor, normal tissue and blood samples were processed for boron measurement by ICP-OES. Results. Several protocols proved potentially useful for BNCT studies in terms of absolute boron concentration in tumor and preferential uptake of boron by tumor tissue, i.e. BPA 15.5 mg 10B/kg iv + GB-10 50 mg 10B/kg iv; BPA 46.5 mg 10B/kg ip; BPA 46.5 mg 10B/kg ip + iv; BPA 46
9. A case of astrocytoma, 19 year history after BNCT
International Nuclear Information System (INIS)
A 39-year-old man had received Boron Neutron Capture Therapy (BNCT) in 1987 for a Grade II Astrocytoma. He gradually exacerbated and received a second operation in 1994. The mass taken in the second operation is almost competent with radiation necrosis. Following that, he shows no signs of recurrence. Currently, he has returned to full time employment in physical labor. This case suggests effectiveness of BNCT for rather low-grade astrocytomas. (author)
10. Dentofacial Asymmetries: Challenging Diagnosis and Treatment Planning.
Science.gov (United States)
Agrawal, Manish; Agrawal, Jiwan Asha; Nanjannawar, Lalita; Fulari, Sangamesh; Kagi, Vishwal
2015-07-01
Dentofacial asymmetry is quite common and when sufficiently severe can require surgical orthodontic intervention. Asymmetries can be classified according to the structures involved into skeletal, dental and functional. In diagnosing asymmetries, a thorough clinical examination and radiographic survey are essential to determine the extent of soft tissue, skeletal, dental and functional involvement. Dental asymmetries, as well as a variety of functional deviations, can be managed orthodontically, whereas significant structural facial asymmetries require a comprehensive orthodontic and orthognathic management. With less severe dental, skeletal and soft tissue deviations the advisability of treatment should be carefully considered. The following article also contains a case report highlighting the importance of proper diagnosis in treatment plan for management of dentofacial asymmetry. PMID:26229387
11. Verification of ophthalmic brachytherapy treatment planning
International Nuclear Information System (INIS)
Ophthalmic brachytherapy dose calculations were performed as an independent verification of commercial dosimetry software (BEBIG Plaque Simulator). Excel spreadsheets were constructed to follow the formalism of the AAPM Task Group No. 43. As a software commissioning tool, TG43 seed-based coordinates were reformatted to be compatible with plaque-based BEBIG dose tables for centrally positioned seeds. Plaque central axis doses were also calculated for rings of seeds. Close agreement with BEBIG doses was obtained in both cases. Tailored spreadsheet versions were subsequently created to verify patient treatment plans. Treatment time and dose to a specified central-axis point are calculated for ROPES plaques fully loaded with I-125 model 6702 seeds. Copyright (2001) Australasian College of Physical Scientists and Engineers in Medicine
12. 49: 3-D treatment planning. 3
International Nuclear Information System (INIS)
For practical 3-D treatment planning, one of the most important perspectives to be used is the 'beam's-eye-view' (BEV), since it displays the relationship of the target volume with the proposed radiation beams. Several BEV features comprise the 3-D planning system U-MPlan, including BEV displays which include contour and shaded solid surfaces of defined anatomy, block entry using joystick and digitizer tablet, automatic block and multi-leaf collimator design, output of block coordinates to hard copy devices, direct output to a computer-controlled block and compensator cutter, use of video digitized radiographs as a backdrop for the BEV graphics, image analysis of digitized films, complete image correlation between BEV-type imaging and CT, MR, PET, etc., and a photon dose calculation algorithm which makes accurate and fast calculations in BEV planes and under blocks. The correlation and use of radiographs and other BEV-type images with CT-type information allows a new degree of precision to be incorporated into radiation therapy planning. 9 refs.; 3 figs
13. Recovery post treatment: plans, barriers and motivators
Directory of Open Access Journals (Sweden)
Duffy Paul
2013-01-01
Full Text Available Abstract Background The increasing focus on achieving a sustained recovery from substance use brings with it a need to better understand the factors (recovery capital that contribute to recovery following treatment. This work examined the factors those in recovery perceive to be barriers to (lack of capital or facilitators of (presence of capital sustained recovery post treatment. Methods A purposive sample of 45 participants was recruited from 11 drug treatment services in northern England. Semi-structured qualitative interviews lasting between 30 and 90 minutes were conducted one to three months after participants completed treatment. Interviews examined key themes identified through previous literature but focused on allowing participants to explore their unique recovery journey. Interviews were transcribed and analysed thematically using a combination of deductive and inductive approaches. Results Participants generally reported high levels of confidence in maintaining their recovery with most planning to remain abstinent. There were indications of high levels of recovery capital. Aftercare engagement was high, often through self referral, with non substance use related activity felt to be particularly positive. Supported housing was critical and concerns were raised about the ability to afford to live independently with financial stability and welfare availability a key concern in general. Employment, often in the substance use treatment field, was a desire. However, it was a long term goal, with substantial risks associated with pursuing this too early. Positive social support was almost exclusively from within the recovery community although the re-building of relationships with family (children in particular was a key motivator post treatment. Conclusions Addressing internal factors and underlying issues i.e. ‘human capital’, provided confidence for continued recovery whilst motivators focused on external factors such as family and
14. Noncoplanar VMAT for nasopharyngeal tumors: Plan quality versus treatment time
International Nuclear Information System (INIS)
Purpose: The authors investigated the potential of optimized noncoplanar irradiation trajectories for volumetric modulated arc therapy (VMAT) treatments of nasopharyngeal patients and studied the trade-off between treatment plan quality and delivery time in radiation therapy. Methods: For three nasopharyngeal patients, the authors generated treatment plans for nine different delivery scenarios using dedicated optimization methods. They compared these scenarios according to dose characteristics, number of beam directions, and estimated delivery times. In particular, the authors generated the following treatment plans: (1) a 4π plan, which is a not sequenced, fluence optimized plan that uses beam directions from approximately 1400 noncoplanar directions and marks a theoretical upper limit of the treatment plan quality, (2) a coplanar 2π plan with 72 coplanar beam directions as pendant to the noncoplanar 4π plan, (3) a coplanar VMAT plan, (4) a coplanar step and shoot (SnS) plan, (5) a beam angle optimized (BAO) coplanar SnS IMRT plan, (6) a noncoplanar BAO SnS plan, (7) a VMAT plan with rotated treatment couch, (8) a noncoplanar VMAT plan with an optimized great circle around the patient, and (9) a noncoplanar BAO VMAT plan with an arbitrary trajectory around the patient. Results: VMAT using optimized noncoplanar irradiation trajectories reduced the mean and maximum doses in organs at risk compared to coplanar VMAT plans by 19% on average while the target coverage remains constant. A coplanar BAO SnS plan was superior to coplanar SnS or VMAT; however, noncoplanar plans like a noncoplanar BAO SnS plan or noncoplanar VMAT yielded a better plan quality than the best coplanar 2π plan. The treatment plan quality of VMAT plans depended on the length of the trajectory. The delivery times of noncoplanar VMAT plans were estimated to be 6.5 min in average; 1.6 min longer than a coplanar plan but on average 2.8 min faster than a noncoplanar SnS plan with comparable
15. Noncoplanar VMAT for nasopharyngeal tumors: Plan quality versus treatment time
Energy Technology Data Exchange (ETDEWEB)
Wild, Esther, E-mail: [email protected]; Bangert, Mark [Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg (Germany); Nill, Simeon [Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG (United Kingdom); Oelfke, Uwe [Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG, United Kingdom and Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg (Germany)
2015-05-15
Purpose: The authors investigated the potential of optimized noncoplanar irradiation trajectories for volumetric modulated arc therapy (VMAT) treatments of nasopharyngeal patients and studied the trade-off between treatment plan quality and delivery time in radiation therapy. Methods: For three nasopharyngeal patients, the authors generated treatment plans for nine different delivery scenarios using dedicated optimization methods. They compared these scenarios according to dose characteristics, number of beam directions, and estimated delivery times. In particular, the authors generated the following treatment plans: (1) a 4π plan, which is a not sequenced, fluence optimized plan that uses beam directions from approximately 1400 noncoplanar directions and marks a theoretical upper limit of the treatment plan quality, (2) a coplanar 2π plan with 72 coplanar beam directions as pendant to the noncoplanar 4π plan, (3) a coplanar VMAT plan, (4) a coplanar step and shoot (SnS) plan, (5) a beam angle optimized (BAO) coplanar SnS IMRT plan, (6) a noncoplanar BAO SnS plan, (7) a VMAT plan with rotated treatment couch, (8) a noncoplanar VMAT plan with an optimized great circle around the patient, and (9) a noncoplanar BAO VMAT plan with an arbitrary trajectory around the patient. Results: VMAT using optimized noncoplanar irradiation trajectories reduced the mean and maximum doses in organs at risk compared to coplanar VMAT plans by 19% on average while the target coverage remains constant. A coplanar BAO SnS plan was superior to coplanar SnS or VMAT; however, noncoplanar plans like a noncoplanar BAO SnS plan or noncoplanar VMAT yielded a better plan quality than the best coplanar 2π plan. The treatment plan quality of VMAT plans depended on the length of the trajectory. The delivery times of noncoplanar VMAT plans were estimated to be 6.5 min in average; 1.6 min longer than a coplanar plan but on average 2.8 min faster than a noncoplanar SnS plan with comparable
16. The therapeutic ratio in BNCT: Assessment using the Rat 9L gliosarcoma brain tumor and spinal cord models
International Nuclear Information System (INIS)
During any radiation therapy, the therapeutic tumor dose is limited by the tolerance of the surrounding normal tissue within the treatment volume. The short ranges of the products of the 10B(n,α)7Li reaction produced during boron neutron capture therapy (BNCT) present an opportunity to increase the therapeutic ratio (tumor dose/normal tissue dose) to levels unprecedented in photon radiotherapy. The mixed radiation field produced during BNCT comprises radiations with different linear energy transfer (LET) and different relative biological effectiveness (RBE). The short ranges of the two high-LET products of the 'B(n,a)'Li reaction make the microdistribution of the boron relative to target cell nuclei of particular importance. Due to the tissue specific distribution of different boron compounds, the term RBE is inappropriate in defining the biological effectiveness of the 10B(n,α)7Li reaction. To distinguish these differences from true RBEs we have used the term open-quotes compound biological effectivenessclose quotes (CBE) factor. The latter can be defined as the product of the true, geometry-independent, RBE for these particles times a open-quotes boron localization factorclose quotes, which will most likely be different for each particular boron compound. To express the total BNCT dose in a common unit, and to compare BNCT doses with the effects of conventional photon irradiation, multiplicative factors (RBEs and CBEs) are applied to the physical absorbed radiation doses from each high-LET component. The total effective BNCT dose is then expressed as the sum of RBE-corrected physical absorbed doses with the unit Gray-equivalent (Gy-Eq)
17. Alopecia areata: a new treatment plan
Directory of Open Access Journals (Sweden)
Alsantali A
2011-07-01
Full Text Available Adel AlsantaliDepartment of Dermatology, King Fahd Armed Forces Hospital, Jeddah, Saudi ArabiaAbstract: Many therapeutic modalities have been used to treat alopecia areata, with variable efficacy and safety profiles. Unfortunately, none of these agents is curative or preventive. Also, many of these therapeutic agents have not been subjected to randomized, controlled trials, and, except for topical immunotherapy, there are few published studies on long-term outcomes. The treatment plan is designed according to the patient's age and extent of disease. In this paper, the therapeutic agents are organized according to their efficacy and safety profiles into first-line, second-line, and third-line options.Keywords: alopecia areata, corticosteroids, immunotherapy, intralesional, phototherapy, sulfasalazine
18. Biodistribution of the boron carriers boronophenylalanine (BPA) and/or decahydrodecaborate (GB-10) for Boron Neutron Capture Therapy (BNCT) in an experimental model of lung metastases
International Nuclear Information System (INIS)
BNCT was proposed for the treatment of diffuse, non-resectable tumors in the lung. We performed boron biodistribution studies with 5 administration protocols employing the boron carriers BPA and/or GB-10 in an experimental model of disseminated lung metastases in rats. All 5 protocols were non-toxic and showed preferential tumor boron uptake versus lung. Absolute tumor boron concentration values were therapeutically useful (25–76 ppm) for 3 protocols. Dosimetric calculations indicate that BNCT at RA-3 would be potentially therapeutic without exceeding radiotolerance in the lung. - Highlights: • We performed experimental boron biodistribution studies for lung metastases. • 3 protocols employing BPA and GB-10 would be therapeutically useful. • BNCT at RA-3 would be potentially therapeutic for experimental lung metastases
19. Quantitative evaluation of boron neutron capture therapy (BNCT) drugs for boron delivery and retention at subcellular scale resolution in human glioblastoma cells with imaging secondary ion mass spectrometry (SIMS)
Science.gov (United States)
Chandra, S.; Ahmad, T.; Barth, R. F.; Kabalka, G. W.
2014-01-01
low phenylalanine diet prior to the initiation of BNCT. Since BPA currently is used clinically for BNCT, our observations may have direct relevance to future clinical studies utilizing this agent and provides support for individualized treatment planning regimens rather than the use of fixed BPA infusion protocols. PMID:24684609
20. An international dosimetry exchange for BNCT part II: computational dosimetry normalizations.
Science.gov (United States)
Riley, K J; Binns, P J; Harling, O K; Albritton, J R; Kiger, W S; Rezaei, A; Sköld, K; Seppälä, T; Savolainen, S; Auterinen, I; Marek, M; Viererbl, L; Nievaart, V A; Moss, R L
2008-12-01
The meaningful sharing and combining of clinical results from different centers in the world performing boron neutron capture therapy (BNCT) requires improved precision in dose specification between programs. To this end absorbed dose normalizations were performed for the European clinical centers at the Joint Research Centre of the European Commission, Petten (The Netherlands), Nuclear Research Institute, Rez (Czech Republic), VTT, Espoo (Finland), and Studsvik, Nyköping (Sweden). Each European group prepared a treatment plan calculation that was bench-marked against Massachusetts Institute of Technology (MIT) dosimetry performed in a large, water-filled phantom to uniformly evaluate dose specifications with an estimated precision of +/-2%-3%. These normalizations were compared with those derived from an earlier exchange between Brookhaven National Laboratory (BNL) and MIT in the USA. Neglecting the uncertainties related to biological weighting factors, large variations between calculated and measured dose are apparent that depend upon the 10B uptake in tissue. Assuming a boron concentration of 15 microg g(-1) in normal tissue, differences in the evaluated maximum dose to brain for the same nominal specification of 10 Gy(w) at the different facilities range between 7.6 and 13.2 Gy(w) in the trials using boronophenylalanine (BPA) as the boron delivery compound and between 8.9 and 11.1 Gy(w) in the two boron sulfhydryl (BSH) studies. Most notably, the value for the same specified dose of 10 Gy(w) determined at the different participating centers using BPA is significantly higher than at BNL by 32% (MIT), 43% (VTT), 49% (JRC), and 74% (Studsvik). Conversion of dose specification is now possible between all active participants and should be incorporated into future multi-center patient analyses. PMID:19175101
1. Biodistribution of the boron carriers boronophenylalanine (BPA) and/or decahydrodecaborate (GB-10) for Boron Neutron Capture Therapy (BNCT) in an experimental model of lung metastases
Energy Technology Data Exchange (ETDEWEB)
D.W. Nigg; Various Others
2014-06-01
BNCT was proposed for the treatment of diffuse, non-resectable tumors in the lung. We performed boron biodistribution studies with 5 administration protocols employing the boron carriers BPA and/or GB-10 in an experimental model of disseminated lung metastases in rats. All 5 protocols were non-toxic and showed preferential tumor boron uptake versus lung. Absolute tumor boron concentration values were therapeutically useful (25–76 ppm) for 3 protocols. Dosimetric calculations indicate that BNCT at RA-3 would be potentially therapeutic without exceeding radiotolerance in the lung.
2. Volume visualization in radiation treatment planning.
Science.gov (United States)
Pelizzari, C A; Chen, G T
2000-12-01
Radiation treatment planning (RTP), historically an image-intensive discipline and one of the first areas in which 3D information from imaging was clinically applied, has become even more critically dependent on accurate 3D definition of target and non-target structures in recent years with the advent of conformal radiation therapy. In addition to the interactive display of wireframe or shaded surface models of anatomic objects, proposed radiation beams, beam modifying devices, and calculated dose distributions, recently significant use has been made of direct visualization of relevant anatomy from image data. Dedicated systems are commercially available for the purpose of geometrically optimizing beam placement, implementing in virtual reality the functionality of standard radiation therapy simulators. Such "CT simulation" systems rely heavily on 3D visualization and on reprojection of image data to produce simulated radiographs for comparison with either diagnostic-quality radiographs made on a simulator or megavoltage images made using the therapeutic beams themselves. Although calculation and analysis of dose distributions is an important component of radiation treatment design, geometric targeting with optimization based on 3D anatomic information is frequently performed as a separate step independent of dose calculations.
3. Radiotherapy Treatment Planning for Testicular Seminoma
Energy Technology Data Exchange (ETDEWEB)
Wilder, Richard B., E-mail: [email protected] [Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL (United States); Buyyounouski, Mark K. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Efstathiou, Jason A. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Beard, Clair J. [Department of Radiation Oncology, Dana-Farber/Brigham and Women' s Cancer Center, Boston, MA (United States)
2012-07-15
Virtually all patients with Stage I testicular seminoma are cured regardless of postorchiectomy management. For patients treated with adjuvant radiotherapy, late toxicity is a major concern. However, toxicity may be limited by radiotherapy techniques that minimize radiation exposure of healthy normal tissues. This article is an evidence-based review that provides radiotherapy treatment planning recommendations for testicular seminoma. The minority of Stage I patients who choose adjuvant treatment over surveillance may be considered for (1) para-aortic irradiation to 20 Gy in 10 fractions, or (2) carboplatin chemotherapy consisting of area under the curve, AUC = 7 Multiplication-Sign 1-2 cycles. Two-dimensional radiotherapy based on bony anatomy is a simple and effective treatment for Stage IIA or IIB testicular seminoma. Centers with expertise in vascular and nodal anatomy may consider use of anteroposterior-posteroanterior fields based on three-dimensional conformal radiotherapy instead. For modified dog-leg fields delivering 20 Gy in 10 fractions, clinical studies support placement of the inferior border at the top of the acetabulum. Clinical and nodal mapping studies support placement of the superior border of all radiotherapy fields at the top of the T12 vertebral body. For Stage IIA and IIB patients, an anteroposterior-posteroanterior boost is then delivered to the adenopathy with a 2-cm margin to the block edge. The boost dose consists of 10 Gy in 5 fractions for Stage IIA and 16 Gy in 8 fractions for Stage IIB. Alternatively, bleomycin, etoposide, and cisplatin chemotherapy for 3 cycles or etoposide and cisplatin chemotherapy for 4 cycles may be delivered to Stage IIA or IIB patients (e.g., if they have a horseshoe kidney, inflammatory bowel disease, or a history of radiotherapy).
4. Federal Facilities Compliance Act, Conceptual Site Treatment Plan. Part 1
International Nuclear Information System (INIS)
This Conceptual Site Treatment Plan was prepared by Ames Laboratory to meet the requirements of the Federal Facilities Compliance Act. Topics discussed in this document include: general discussion of the plan, including the purpose and scope; technical aspects of preparing plans, including the rationale behind the treatability groupings and a discussion of characterization issues; treatment technology needs and treatment options for specific waste streams; low-level mixed waste options; TRU waste options; and future waste generation from restoration activities
5. Federal Facilities Compliance Act, Conceptual Site Treatment Plan. Part 1
Energy Technology Data Exchange (ETDEWEB)
NONE
1993-10-29
This Conceptual Site Treatment Plan was prepared by Ames Laboratory to meet the requirements of the Federal Facilities Compliance Act. Topics discussed in this document include: general discussion of the plan, including the purpose and scope; technical aspects of preparing plans, including the rationale behind the treatability groupings and a discussion of characterization issues; treatment technology needs and treatment options for specific waste streams; low-level mixed waste options; TRU waste options; and future waste generation from restoration activities.
6. Feasibility of BNCT radiobiological experiments at the HYTHOR facility
Science.gov (United States)
Esposito, J.; Ceballos, C.; Soncin, M.; Fabris, C.; Friso, E.; Moro, D.; Colautti, P.; Jori, G.; Rosi, G.; Nava, E.
2008-06-01
HYTHOR (HYbrid Thermal spectrum sHifter tapirO Reactor) is a new thermal-neutron irradiation facility, which was installed and became operative in mid 2005 at the TAPIRO (TAratura PIla Rapida potenza 0) fast reactor, in the Casaccia research centre (near Rome) of ENEA (Ente per le Nuove tecnologie Energia ed Ambiente). The facility has been designed for in vivo radiobiological studies. In HYTHOR irradiation cavity, 1-6 mice can be simultaneously irradiated to study skin melanoma treatments with the BNCT (boron neutron capture therapy). The therapeutic effects of HYTHOR radiation field on mouse melanoma has been studied as a preliminary investigation before studying the tumour local control due to boron neutron capture effect after boronated molecule injection. The method to properly irradiate small animals has been precisely defined. Results show that HYTHOR radiation field is by itself effective in reducing the tumour-growth rate. This finding has to be taken into account in studying the effectiveness of new 10B carriers. A method to properly measure the reduction of the tumour-growth rate is reported and discussed.
7. Collimator and shielding design for boron neutron capture therapy (BNCT) facility at TRIGA MARK II reactor
International Nuclear Information System (INIS)
The geometry of reactor core, thermal column, collimator and shielding system for BNCT application of TRIGA MARK II Reactor were simulated with MCNP5 code. Neutron particle lethargy and dose were calculated with MCNPX code. Neutron flux in a sample located at the end of collimator after normalized to measured value (Eid Mahmoud Eid Abdel Munem, 2007) at 1 MW power was 1.06 x 108 n/ cm2/ s. According to IAEA (2001) flux of 1.00 x 109 n/ cm2/ s requires three hours of treatment. Few modifications were needed to get higher flux. (Author)
8. Determination of the irradiation field at the research reactor TRIGA Mainz for BNCT.
Science.gov (United States)
Nagels, S; Hampel, G; Kratz, J V; Aguilar, A L; Minouchehr, S; Otto, G; Schmidberger, H; Schütz, C; Vogtländer, L; Wortmann, B
2009-07-01
For the application of the BNCT for the excorporal treatment of organs at the TRIGA Mainz, the basic characteristics of the radiation field in the thermal column as beam geometry, neutron and gamma ray energies, angular distributions, neutron flux, as well as absorbed gamma and neutron doses must be determined in a reproducible way. To determine the mixed irradiation field thermoluminescence detectors (TLD) made of CaF(2):Tm with a newly developed energy-compensation filter system and LiF:Mg,Ti materials with different (6)Li concentrations and different thicknesses as well as thin gold foils were used. PMID:19380234
9. Physical and biological dosimetry at the RA-3 facility for small animal irradiation: preliminary BNCT studies in an experimental model of oral cancer
International Nuclear Information System (INIS)
Boron Neutron Capture Therapy (BNCT) is a binary treatment modality based on the capture reaction that occurs between thermal neutrons and boron-10 atoms that accumulate selectively in tumor tissue, emitting high linear energy transfer (LET), short range (5-9 microns) particles (alpha y 7Li). Thus, BNCT would potentially target tumor tissue selectively, sparing normal tissue. Herein we evaluated the feasibility of treating experimental oral mucosa tumors with BNCT at RA-3 (CAE) employing the hamster cheek pouch oral cancer model and characterized the irradiation field at the RA-3 facility. We evaluated the therapeutic effect on tumor of BNCT mediated by BPA in the hamster cheek pouch oral cancer model and the potential radio toxic effects in normal tissue. We evidenced a moderate biological response in tumor, with no radio toxic effects in normal tissue following irradiations with no shielding for the animal body. Given the sub-optimal therapeutic response, we designed and built a 6Li2CO3 shielding for the body of the animal to increase the irradiation dose to tumor, without exceeding normal tissue radio tolerance. The measured absolute magnitude of thermal neutron flux and the characterization of the beam with and without the shielding in place, suggest that the irradiation facility in the thermal column of RA-3 would afford an excellent platform to perform BNCT studies in vitro and in vivo in small experimental animals. The present findings must be confirmed and extended by performing in vivo BNCT radiobiological studies in small experimental animals, employing the shielding device for the animal body. (author)
10. Dosimetric analysis of BNCT - Boron Neutron Capture Therapy - coupled to 252Cf brachytherapy
International Nuclear Information System (INIS)
The incidence of brain tumors is increasing in world population; however, the treatments employed in this type of tumor have a high rate of failure and in some cases have been considered palliative, depending on histology and staging of tumor. Its necessary to achieve the control tumor dose without the spread irradiation cause damage in the brain, affecting patient neurological function. Stereotactic radiosurgery is a technique that achieves this; nevertheless, other techniques that can be used on the brain tumor control must be developed, in order to guarantee lower dose on health surroundings tissues other techniques must be developing. The 252Cf brachytherapy applied to brain tumors has already been suggested, showing promising results in comparison to photon source, since the active source is placed into the tumor, providing greater dose deposition, while more distant regions are spared. BNCT - Boron Neutron Capture Therapy - is another technique that is in developing to brain tumors control, showing theoretical superiority on the rules of conventional treatments, due to a selective irradiation of neoplasics cells, after the patient receives a borate compound infusion and be subjected to a epithermal neutrons beam. This work presents dosimetric studies of the coupling techniques: BNCT with 252Cf brachytherapy, conducted through computer simulation in MCNP5 code, using a precise and well discretized voxel model of human head, which was incorporated a representative Glioblastoma Multiform tumor. The dosimetric results from MCNP5 code were exported to SISCODES program, which generated isodose curves representing absorbed dose rate in the brain. Isodose curves, neutron fluency, and dose components from BNCT and 252Cf brachytherapy are presented in this paper. (author)
11. Protocols for BNCT of glioblastoma multiforme at Brookhaven: Practical considerations
Energy Technology Data Exchange (ETDEWEB)
Chanana, A.D.; Coderre, J.A.; Joel, D.D.; Slatkin, D.N.
1996-12-31
In this report we discuss some issues considered in selecting initial protocols for boron neutron capture therapy (BNCT) of human glioblastoma multiforme. First the tolerance of normal tissues, especially the brain, to the radiation field. Radiation doses limits were based on results with human and animal exposures. Estimates of tumor control doses were based on the results of single-fraction photon therapy and single fraction BNCT both in humans and experimental animals. Of the two boron compounds (BSH and BPA), BPA was chosen since a FDA-sanctioned protocol for distribution in humans was in effect at the time the first BNCT protocols were written and therapy studies in experimental animals had shown it to be more effective than BSH.
12. Proceedings of neutron irradiation technical meeting on BNCT
Energy Technology Data Exchange (ETDEWEB)
NONE
2000-10-01
The 'Neutron Irradiation Technical Meeting for Boron Neutron Capture Therapy (BNCT)' was held on March 13, 2000 at Tokai Research Establishment. The Meeting is aimed to introduce the neutron beam facility for medical irradiation at JRR-4 to Japanese researchers widely, as well as providing an opportunity for young researchers, engineers, medical representatives such surgeons and doctors of pharmacology to present their research activities and to exchange valuable information. JAERI researcher presented the performance and the irradiation technology in the JRR-4 neutron beam facility, while external researchers made various and beneficial presentations containing such accelerator-based BNCT, spectrum-shifter, biological effect, pharmacological development and so on. In this meeting, a special lecture titled 'The Dawn of BNCT and Its Development.' was given by MD, Prof. Takashi Minobe, an executive director of Japan Foundation for Emergency Medicine. The 11 of the presented papers are indexed individually. (J.P.N.)
13. Dosimetry audit of radiotherapy treatment planning systems
International Nuclear Information System (INIS)
In radiotherapy Treatment Planning Systems (TPS) various calculation algorithms are used. The accuracy of dose calculations has to be verified. Numerous phantom types, detectors and measurement methodologies are proposed to verify the TPS calculations with dosimetric measurements. A heterogeneous slab phantom has been designed within a Coordinated Research Project (CRP) of the IAEA. The heterogeneous phantom was developed in the frame of the IAEA CRP. The phantom consists of frame slabs made with polystyrene and exchangeable inhomogeneity slabs equivalent to bone or lung tissue. Special inserts allow to position thermoluminescent dosimeters (TLD) capsules within the polystyrene slabs below the bone or lung equivalent slabs and also within the lung equivalent material. Additionally, there are inserts that allow to position films or ionisation chamber in the phantom. Ten Polish radiotherapy centres (of 30 in total) were audited during on-site visits. Six different TPSs and five calculation algorithms were examined in the presence of inhomogeneities. Generally, most of the results from TLD were within 5 % tolerance. Differences between doses calculated by TPSs and measured with TLD did not exceed 4 % for bone and polystyrene equivalent materials. Under the lung equivalent material, on the beam axis the differences were lower than 5 %, whereas inside the lung equivalent material, off the beam axis, in some cases they were of around 7 %. The TLD results were confirmed with the ionisation chamber measurements. The comparison results of the calculations and the measurements allow to detect limitations of TPS calculation algorithms. The audits performed with the use of heterogeneous phantom and TLD seem to be an effective tool for detecting the limitations in the TPS performance or beam configuration errors at audited radiotherapy departments. (authors)
14. Characterisation of an accelerator-based neutron source for BNCT versus beam energy
Energy Technology Data Exchange (ETDEWEB)
Agosteo, S. E-mail: [email protected]; Curzio, G.; D' Errico, F.; Nath, R.; Tinti, R
2002-01-01
Neutron capture in {sup 10}B produces energetic alpha particles that have a high linear energy transfer in tissue. This results in higher cell killing and a higher relative biological effectiveness compared to photons. Using suitably designed boron compounds which preferentially localize in cancerous cells instead of healthy tissues, boron neutron capture therapy (BNCT) has the potential of providing a higher tumor cure rate within minimal toxicity to normal tissues. This clinical approach requires a thermal neutron source, generally a nuclear reactor, with a fluence rate sufficient to deliver tumorcidal doses within a reasonable treatment time (minutes). Thermal neutrons do not penetrate deeply in tissue, therefore BNCT is limited to lesions which are either superficial or otherwise accessible. In this work, we investigate the feasibility of an accelerator-based thermal neutron source for the BNCT of skin melanomas. The source was designed via MCNP Monte Carlo simulations of the thermalization of a fast neutron beam, generated by 7 MeV deuterons impinging on a thick target of beryllium. The neutron field was characterized at several deuteron energies (3.0-6.5 MeV) in an experimental structure installed at the Van De Graaff accelerator of the Laboratori Nazionali di Legnaro, in Italy. Thermal and epithermal neutron fluences were measured with activation techniques and fast neutron spectra were determined with superheated drop detectors (SDD). These neutron spectrometry and dosimetry studies indicated that the fast neutron dose is unacceptably high in the current design. Modifications to the current design to overcome this problem are presented.
15. Considerations for boron neutron capture therapy studies; Consideracoes sobre o estudo da BNCT (terapia de captura neutronica por boro)
Energy Technology Data Exchange (ETDEWEB)
Faria Gaspar, P. de
1994-12-31
Radiotherapy is indispensable as a mean to eradicate deeply or infiltrating tumor tissue that can not be removed surgically. Therefore, it is not selective and may also kill the surrounding health tissue. The principle of BNCT (Boron Neutron Capture Therapy) consist in targeting a tumor selectively with a boron-10 compound. This nuclide has a large capture cross section for thermal neutrons and the nuclear reaction and the delivered energy in locus will selective the tumor. Since its initial proposal in 1963 BNCT has made much progress, however it is not used in a routine treatment. In this work it was approached some complex procedures, as the obtention of selective boron compounds, the adequate set up of neutron beams, the biodistribution, the in vivo and in vitro studies, and also human patients treatments. This work provide fundamentals about BNCT to professional of different areas of knowledge since it comprises multidisciplinary study. It includes appendixes for the ones not related to the field for a better comprehension of the many aspects involved. It is also presented a glossary containing technical and basic aspects involved. It is also presented a glossary containing technical and basic terms referred in the work. (author). 174 refs, 1 fig, 12 apps.
16. SU-D-BRD-04: The Impact of Automatic Radiation Therapy Plan Checks in Treatment Planning
Energy Technology Data Exchange (ETDEWEB)
Gopan, O; Yang, F; Ford, E [University of Washington, Seattle, WA (United States)
2015-06-15
Purpose: The physics plan check verifies various aspects of a treatment plan after dosimetrists have finished creating the plan. Some errors in the plan which are caught by the physics check could be caught earlier in the departmental workflow. The purpose of this project was to evaluate a plan checking script that can be run within the treatment planning system (TPS) by the dosimetrists prior to plan approval and export to the record and verify system. Methods: A script was created in the Pinnacle TPS to automatically check 15 aspects of a plan for clinical practice conformity. The script outputs a list of checks which the plan has passed and a list of checks which the plan has failed so that appropriate adjustments can be made. For this study, the script was run on a total of 108 plans: IMRT (46/108), VMAT (35/108) and SBRT (27/108). Results: Of the plans checked by the script, 77/108 (71%) failed at least one of the fifteen checks. IMRT plans resulted in more failed checks (91%) than VMAT (51%) or SBRT (63%), due to the high failure rate of an IMRT-specific check, which checks that no IMRT segment < 5 MU. The dose grid size and couch removal checks caught errors in 10% and 14% of all plans – errors that ultimately may have resulted in harm to the patient. Conclusion: Approximately three-fourths of the plans being examined contain errors that could be caught by dosimetrists running an automated script embedded in the TPS. The results of this study will improve the departmental workflow by cutting down on the number of plans that, due to these types of errors, necessitate re-planning and re-approval of plans, increase dosimetrist and physician workload and, in urgent cases, inconvenience patients by causing treatment delays.
17. Monitoring Hazardous Fuels Treatments: Southeast Regional Plan
Data.gov (United States)
US Fish and Wildlife Service, Department of the Interior — The purpose of this document is to provide technical guidance on monitoring activities to refuge staff involved in planning and conducting hazardous fuel...
18. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors
Directory of Open Access Journals (Sweden)
Samia de Freitas Brandao
2013-07-01
Full Text Available Objective Comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and Methods Simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. Results Intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h-1.p-1.s, respectively, on the healthy tissue, on the balloon periphery and on the I 1 and I 2 tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E-09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h-1.p-1.s, respectively on the healthy tissue, on the target tumor and on the I 1 and I 2 infiltration zones. Conclusion Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones.
19. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors
International Nuclear Information System (INIS)
Objective: comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and methods: simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. Results: intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h-1.p-1.s, respectively, on the healthy tissue, on the balloon periphery and on the /1 and /2 tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E-09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h-1.p-1.s, respectively on the healthy tissue, on the target tumor and on the /1 and /2 infiltration zones. Conclusion: Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones. (author)
20. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors
Energy Technology Data Exchange (ETDEWEB)
Brandao, Samia de Freitas, E-mail: [email protected] [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Campos, Tarcisio Passos Ribeiro de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)
2013-06-15
Objective: comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and methods: simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. Results: intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h{sup -1}.p{sup -1}.s, respectively, on the healthy tissue, on the balloon periphery and on the /{sub 1} and /{sub 2} tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E-09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h{sup -1}.p{sup -1}.s, respectively on the healthy tissue, on the target tumor and on the /{sub 1} and /{sub 2} infiltration zones. Conclusion: Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones. (author)
1. Boron Neutron Capture Therapy (BNCT) in an Oral Precancer Model: Therapeutic Benefits and Potential Toxicity of a Double Application of BNCT with a Six-Week Interval
International Nuclear Information System (INIS)
Given the clinical relevance of locoregional recurrences in head and neck cancer, we developed a novel experimental model of premalignant tissue in the hamster cheek pouch for long-term studies and demonstrated the partial inhibitory effect of a single application of Boron Neutron Capture Therapy (BNCT) on tumor development from premalignant tissue. The aim of the present study was to evaluate the effect of a double application of BNCT with a 6 week interval in terms of inhibitory effect on tumor development, toxicity and DNA synthesis. We performed a double application, 6 weeks apart, of (1) BNCT mediated by boronophenylalanine (BPA-BNCT); (2) BNCT mediated by the combined application of decahydrodecaborate (GB-10) and BPA ((GB-10 + BPA)-BNCT) or (3) beam-only, at RA-3 nuclear reactor and followed the animals for 8 months. The control group was cancerized and sham-irradiated. BPA-BNCT, (GB- 10 + BPA)-BNCT and beam-only induced a reduction in tumor development from premalignant tissue that persisted until 8, 3, and 2 months respectively. An early maximum inhibition of 100% was observed for all 3 protocols. No normal tissue radiotoxicity was detected. Reversible mucositis was observed in premalignant tissue, peaking at 1 week and resolving by the third week after each irradiation. Mucositis after the second application was not exacerbated by the first application. DNA synthesis was significantly reduced in premalignant tissue 8 months post-BNCT. A double application of BPA-BNCT and (GB-10 + BPA)-BNCT, 6 weeks apart, could be used therapeutically at no additional cost in terms of radiotoxicity in normal and dose-limiting tissues.
2. Feasibility of the Utilization of BNCT in the Fast Neutron Therapy Beam at Fermilab
Science.gov (United States)
Langen, Katja; Lennox, Arlene J.; Kroc, Thomas K.; DeLuca, Jr., Paul M.
2000-06-01
The Neutron Therapy Facility at Fermilab has treated cancer patients since 1976. Since then more than 2,300 patients have been treated and a wealth of clinical information accumulated. The therapeutic neutron beam at Fermilab is produced by bombarding a beryllium target with 66 MeV protons. The resulting continuous neutron spectrum ranges from thermal to 66 MeV in neutron energy. It is clear that this spectrum is not well suited for the treatment of tumors with boron neutron capture therapy (BNCT) only However, since this spectrum contains thermal and epithermal components the authors are investigating whether BNCT can be used in this beam to boost the tumor dose. There are clinical scenarios in which a selective tumor dose boost of 10 - 15% could be clinically significant. For these cases the principal treatment would still be fast neutron therapy but a tumor boost could be used either to deliver a higher dose to the tumor tissue or to reduce the dose to the normal healthy tissue while maintaining the absorbed dose level in the tumor tissue.
3. INEL BNCT Program: Volume 5, No. 9. Bulletin, September 1991
Energy Technology Data Exchange (ETDEWEB)
Ackermann, A.L. [ed.
1991-12-31
This Bulletin presents a summary of accomplishments and highlights of the Idaho National Engineering Laboratorys (INEL) Boron Neutron Capture Therapy (BNCT) Program for September 1991. This bulletin includes information on the brain tumor and melanoma research programs, Power Burst Facility (PBF) technical support and modifications, PBF operations, and updates to the animal data charts.
4. Automated treatment planning engine for prostate seed implant brachytherapy
International Nuclear Information System (INIS)
Purpose: To develop a computer-intelligent planning engine for automated treatment planning and optimization of ultrasound- and template-guided prostate seed implants. Methods and Materials: The genetic algorithm was modified to reflect the 2D nature of the implantation template. A multi-objective decision scheme was used to rank competing solutions, taking into account dose uniformity and conformity to the planning target volume (PTV), dose-sparing of the urethra and the rectum, and the sensitivity of the resulting dosimetry to seed misplacement. Optimized treatment plans were evaluated using selected dosimetric quantifiers, dose-volume histogram (DVH), and sensitivity analysis based on simulated seed placement errors. These dosimetric planning components were integrated into the Prostate Implant Planning Engine for Radiotherapy (PIPER). Results: PIPER has been used to produce a variety of plans for prostate seed implants. In general, maximization of the minimum peripheral dose (mPD) for given implanted total source strength tended to produce peripherally weighted seed patterns. Minimization of the urethral dose further reduced the loading in the central region of the PTV. Isodose conformity to the PTV was achieved when the set of objectives did not reflect seed positioning uncertainties; the corresponding optimal plan generally required fewer seeds and higher source strength per seed compared to the manual planning experience. When seed placement uncertainties were introduced into the set of treatment planning objectives, the optimal plan tended to reach a compromise between the preplanned outcome and the likelihood of retaining the preferred outcome after implantation. The reduction in the volatility of such seed configurations optimized under uncertainty was verified by sensitivity studies. Conclusion: An automated treatment planning engine incorporating real-time sensitivity analysis was found to be a useful tool in dosimetric planning for prostate
5. Proposed Site Treatment Plan (PSTP). STP reference document
Energy Technology Data Exchange (ETDEWEB)
NONE
1995-02-22
The Department of Energy (DOE) is required by Section 3021(b) of the Resource Conservation and Recovery Act (RCRA), as amended by the Federal Facility Compliance Act (FFCAct), to prepare a plan describing the development of treatment capacities and technologies for treating mixed waste (hazardous/radioactive waste). DOE decided to prepare its site treatment plan in a three phased approach. The first phase, called the Conceptual Site Treatment Plan (CSTP), was issued in October 1993. At the Savannah River Site (SRS) the CSTP described mixed waste streams generated at SRS and listed treatment scenarios for each waste stream utilizing an onsite, offsite DOE, and offsite or onsite commercial or vendor treatment option. The CSTP is followed by the Draft Site Treatment Plan (DSTP), due to be issued in August 1994. The DSTP, the current activity., will narrow the options discussed in the CSTP to a preferred treatment option, if possible, and will include waste streams proposed to be shipped to SRS from other DOE facilities as well as waste streams SRS may send offsite for treatment. The SRS DSTP process has been designed to address treatment options for each of the sites mixed waste streams. The SRS Proposed Site Treatment Plan (PSTP) is due to be issued in February 1995. The compliance order would be derived from the PSTP.
6. Proposed Site Treatment Plan (PSTP). STP reference document
International Nuclear Information System (INIS)
The Department of Energy (DOE) is required by Section 3021(b) of the Resource Conservation and Recovery Act (RCRA), as amended by the Federal Facility Compliance Act (FFCAct), to prepare a plan describing the development of treatment capacities and technologies for treating mixed waste (hazardous/radioactive waste). DOE decided to prepare its site treatment plan in a three phased approach. The first phase, called the Conceptual Site Treatment Plan (CSTP), was issued in October 1993. At the Savannah River Site (SRS) the CSTP described mixed waste streams generated at SRS and listed treatment scenarios for each waste stream utilizing an onsite, offsite DOE, and offsite or onsite commercial or vendor treatment option. The CSTP is followed by the Draft Site Treatment Plan (DSTP), due to be issued in August 1994. The DSTP, the current activity., will narrow the options discussed in the CSTP to a preferred treatment option, if possible, and will include waste streams proposed to be shipped to SRS from other DOE facilities as well as waste streams SRS may send offsite for treatment. The SRS DSTP process has been designed to address treatment options for each of the site's mixed waste streams. The SRS Proposed Site Treatment Plan (PSTP) is due to be issued in February 1995. The compliance order would be derived from the PSTP
7. The Trimeric Model: A New Model of Periodontal Treatment Planning
OpenAIRE
Azouni, Khalid G; Tarakji, Bassel
2014-01-01
Treatment of periodontal disease is a complex and multidisciplinary procedure, requiring periodontal, surgical, restorative, and orthodontic treatment modalities. Several authors attempted to formulate models for periodontal treatment that orders the treatment steps in a logical and easy to remember manner. In this article, we discuss two models of periodontal treatment planning from two of the most well-known textbook in the specialty of periodontics internationally. Then modify them to arri...
8. Managing Health Care After Cancer Treatment: A Wellness Plan
OpenAIRE
Moye, Jennifer; Langdon, Maura; Jones, Janice M.; Haggstrom, David; Naik, Aanand D.
2014-01-01
Many patients and health care providers lack awareness of both the existence of, and treatments for, lingering distress and disability after treatment. A cancer survivorship wellness plan can help ensure that any referral needs for psychosocial and other restorative care after cancer treatment are identified.
9. Manpower Planning for Wastewater Treatment Plants.
Science.gov (United States)
Davies, J. Kenneth; And Others
This document discusses the components necessary in the development of a forecasting process by which manpower needs can be determined and the development of action programs by which the projected needs may be satisfied. The primary focus of this manual is directed at that person in a state agency who has the responsibility for planning the…
10. Optimal partial-arcs in VMAT treatment planning
CERN Document Server
Wala, Jeremiah; Chen, Wei; Craft, David
2012-01-01
Purpose: To improve the delivery efficiency of VMAT by extending the recently published VMAT treatment planning algorithm vmerge to automatically generate optimal partial-arc plans. Methods and materials: A high-quality initial plan is created by solving a convex multicriteria optimization problem using 180 equi-spaced beams. This initial plan is used to form a set of dose constraints, and a set of partial-arc plans is created by searching the space of all possible partial-arc plans that satisfy these constraints. For each partial-arc, an iterative fluence map merging and sequencing algorithm (vmerge) is used to improve the delivery efficiency. Merging continues as long as the dose quality is maintained above a user-defined threshold. The final plan is selected as the partial arc with the lowest treatment time. The complete algorithm is called pmerge. Results: Partial-arc plans are created using pmerge for a lung, liver and prostate case, with final treatment times of 127, 245 and 147 seconds. Treatment times...
11. BNCT dose calculation in irregular fields using the sector integration method
Energy Technology Data Exchange (ETDEWEB)
Blaumann, H.R. E-mail: [email protected]; Sanz, D.E.; Longhino, J.M.; Larrieu, O.A. Calzetta
2004-11-01
Irregular fields for boron neutron capture therapy (BNCT) have been already proposed to spare normal tissue in the treatment of superficial tumors. This added dependence would require custom measurements and/or to have a secondary calculation system. As a first step, we implemented the sector-integration method for irregular field calculation in a homogeneous medium and on the central beam axis. The dosimetric responses (fast neutron and photon dose and thermal neutron flux), are calculated by sector integrating the measured responses of circular fields over the field boundary. The measurements were carried out at our BNCT facility, the RA-6 reactor (Argentina). The input data were dosimetric responses for circular fields measured at different depths in a water phantom using ionisation and activation techniques. Circular fields were formed by shielding the beam with two plates: borated polyethilene plus lead. As a test, the dosimetric responses of a 7x4 cm{sup 2} rectangular field, were measured and compared to calculations, yielding differences less than 3% in equivalent dose at any depth indicating that the tool is suitable for redundant calculations.
12. BNCT dose calculation in irregular fields using the sector integration method.
Science.gov (United States)
Blaumann, H R; Sanz, D E; Longhino, J M; Larrieu, O A Calzetta
2004-11-01
Irregular fields for boron neutron capture therapy (BNCT) have been already proposed to spare normal tissue in the treatment of superficial tumors. This added dependence would require custom measurements and/or to have a secondary calculation system. As a first step, we implemented the sector-integration method for irregular field calculation in a homogeneous medium and on the central beam axis. The dosimetric responses (fast neutron and photon dose and thermal neutron flux), are calculated by sector integrating the measured responses of circular fields over the field boundary. The measurements were carried out at our BNCT facility, the RA-6 reactor (Argentina). The input data were dosimetric responses for circular fields measured at different depths in a water phantom using ionisation and activation techniques. Circular fields were formed by shielding the beam with two plates: borated polyethilene plus lead. As a test, the dosimetric responses of a 7x4 cm(2) rectangular field, were measured and compared to calculations, yielding differences less than 3% in equivalent dose at any depth indicating that the tool is suitable for redundant calculations.
13. Radiation field characterization of a BNCT research facility using Monte Carlo method - code MCNP-4B
International Nuclear Information System (INIS)
Boron Neutron Capture Therapy - BNCT - is a selective cancer treatment and arises as an alternative therapy to treat cancer when usual techniques - surgery, chemotherapy or radiotherapy - show no satisfactory results. The main proposal of this work is to project a facility to BNCT studies. This facility relies on the use of an Am Be neutron source and on a set of moderators, filters and shielding which will provide the best neutron/gamma beam characteristic for these Becton studies, i.e., high intensity thermal and/or epithermal neutron fluxes and with the minimum feasible gamma rays and fast neutrons contaminants. A computational model of the experiment was used to obtain the radiation field in the sample irradiation position. The calculations have been performed with the MCNP 4B Monte Carlo Code and the results obtained can be regarded as satisfactory, i.e., a thermal neutron fluencyNT = 1,35x108 n/cm , a fast neutron dose of 5,86x10-10 Gy/NT and a gamma ray dose of 8,30x10-14 Gy/NT. (author)
14. 300 Area waste acid treatment system closure plan. Revision 1
International Nuclear Information System (INIS)
This section provides a description of the Hanford Site, identifies the proposed method of 300 Area Waste Acid Treatment System (WATS) closure, and briefly summarizes the contents of each chapter of this plan
15. Evolving treatment plan quality criteria from institution-specific experience
International Nuclear Information System (INIS)
Purpose: The dosimetric aspects of radiation therapy treatment plan quality are usually evaluated and reported with dose volume histogram (DVH) endpoints. For clinical practicality, a small number of representative quantities derived from the DVH are often used as dose endpoints to summarize the plan quality. National guidelines on reference values for such quantities for some standard treatment approaches are often used as acceptance criteria to trigger treatment plan review. On the other hand, treatment prescription and planning approaches specific to each institution warrants the need to report plan quality in terms of practice consistency and with respect to institution-specific experience. The purpose of this study is to investigate and develop a systematic approach to record and characterize the institution-specific plan experience and use such information to guide the design of plan quality criteria. In the clinical setting, this approach will assist in (1) improving overall plan quality and consistency and (2) detecting abnormal plan behavior for retrospective analysis. Methods: The authors propose a self-evolving methodology and have developed an in-house prototype software suite that (1) extracts the dose endpoints from a treatment plan and evaluates them against both national standard and institution-specific criteria and (2) evolves the statistics for the dose endpoints and updates institution-specific criteria. Results: The validity of the proposed methodology was demonstrated with a database of prostate stereotactic body radiotherapy cases. As more data sets are accumulated, the evolving institution-specific criteria can serve as a reliable and stable consistency measure for plan quality and reveals the potential use of the ''tighter'' criteria than national standards or projected criteria, leading to practice that may push to shrink the gap between plans deemed acceptable and the underlying unknown optimality. Conclusions: The authors have developed
16. Generating Treatment Plan in Medicine: A Data Mining Approach
OpenAIRE
2009-01-01
This study reports on a research effort on generating treatment plan to handle the error and complexity of treatment process for healthcare providers. Focus has been given for outpatient and was based on data collected from various health centers throughout Malaysia. These clinical data were recorded using SOAP (Subjective, Objective, Assessment and Plan) format approach as being practiced in medicine and were recorded electronically via Percuro Clinical Information System (Percuro). Cross-In...
17. Comparing Treatment Plan in All Locations of Esophageal Cancer
OpenAIRE
Lin, Jang-Chun; Tsai, Jo-Ting; Chang, Chih-Chieh; Jen, Yee-Min; Li, Ming-Hsien; Liu, Wei-Hsiu
2015-01-01
Abstract The aim of this study was to compare treatment plans of volumetric modulated arc therapy (VMAT) with intensity-modulated radiotherapy (IMRT) for all esophageal cancer (EC) tumor locations. This retrospective study from July 2009 to June 2014 included 20 patients with EC who received definitive concurrent chemoradiotherapy with radiation doses >50.4 Gy. Version 9.2 of Pinnacle3 with SmartArc was used for treatment planning. Dosimetric quality was evaluated based on doses to several or...
18. A minimally invasive approach for a compromised treatment plan.
Science.gov (United States)
Maibaum, Wayne W
2016-01-01
A primary goal in dentistry is the execution of appropriate treatment plans that are minimally invasive and maintainable. However, it is sometimes necessary to repair existing dental restorations or revise treatment plans to accommodate changes in a patient's condition. In the present case, a patient who was satisfied with a removable partial overdenture lost a critical abutment tooth. A creative, minimally invasive approach enabled the patient to keep his existing partial prosthesis and avoid the need for a full reconstruction or complete denture.
19. 300 Area waste acid treatment system closure plan
International Nuclear Information System (INIS)
The Hanford Facility Dangerous Waste Permit Application is considered to be a single application organized into a General Information Portion (document number DOERL-91-28) and a Unit-Specific Portion. The scope of the Unit-Specific Portion includes closure plan documentation submitted for individual, treatment, storage, and/or disposal units undergoing closure, such as the 300 Area Waste Acid Treatment System. Documentation contained in the General Information Portion is broader in nature and could be used by multiple treatment, storage, and/or disposal units (e.g., the glossary provided in the General Information Portion). Whenever appropriate, 300 Area Waste Acid Treatment System documentation makes cross-reference to the General Information Portion, rather than duplicating text. This 300 Area Waste Acid Treatment System Closure Plan (Revision 2) includes a Hanford Facility Dangerous Waste Permit Application, Part A, Form 3. Information provided in this closure plan is current as of April 1999
20. 300 Area waste acid treatment system closure plan
Energy Technology Data Exchange (ETDEWEB)
LUKE, S.N.
1999-05-17
The Hanford Facility Dangerous Waste Permit Application is considered to be a single application organized into a General Information Portion (document number DOERL-91-28) and a Unit-Specific Portion. The scope of the Unit-Specific Portion includes closure plan documentation submitted for individual, treatment, storage, and/or disposal units undergoing closure, such as the 300 Area Waste Acid Treatment System. Documentation contained in the General Information Portion is broader in nature and could be used by multiple treatment, storage, and/or disposal units (e.g., the glossary provided in the General Information Portion). Whenever appropriate, 300 Area Waste Acid Treatment System documentation makes cross-reference to the General Information Portion, rather than duplicating text. This 300 Area Waste Acid Treatment System Closure Plan (Revision 2) includes a Hanford Facility Dangerous Waste Permit Application, Part A, Form 3. Information provided in this closure plan is current as of April 1999.
1. Planning of emergency medical treatment in nuclear power plant
International Nuclear Information System (INIS)
Medical staffs and health physicists have shown deep concerning at the emergency plans of nuclear power plants after the TMI nuclear accident. The most important and basic countermeasure for accidents was preparing appropriate and concrete organization and plans for treatment. We have planed emergency medical treatment for radiation workers in a nuclear power plant institute. The emergency medical treatment at institute consisted of two stages, that is on-site emergency treatment at facility medical service. In first step of planning in each stage, we selected and treatment at facility medical service. In first step of planning in each stage, we selected and analyzed all possible accidents in the institute and discussed on practical treatments for some possible accidents. The manuals of concrete procedure of emergency treatment for some accidents were prepared following discussion and facilities and equipment for medical treatment and decontamination were provided. All workers in the institute had periodical training and drilling of on-site emergency treatment and mastered technique of first aid. Decontamination and operation rooms were provided in the facillity medical service. The main functions at the facility medical service have been carried out by industrial nurses. Industrial nurses have been in close co-operation with radiation safety officers and medical doctors in regional hospital. (author)
2. Explicit and convex optimization of plan quality measures in intensity-modulated radiation therapy treatment planning
CERN Document Server
Engberg, Lovisa; Forsgren, Anders; Hårdemark, Björn
2016-01-01
Given the widespread agreement that doses-at-volume play important roles in quality assessment of radiation therapy treatment plans, planning objectives that correlate well with explicit dose-at-volume optimization are likely to correlate well with plan quality. In this study, planning objectives are formulated to explicitly either minimize or maximize convex approximations of dose-at-volume, namely, mean-tail-doses. This is in contrast to the conventionally used planning objectives, which are used to maximize clinical goal fulfilment by relating to deviations from dose-at-volume thresholds. Advantages of the proposed planning objectives are investigated through juxtaposition with conventional objectives in a computational study of two patient cases, each with three doses-at-volume to be minimized subject to PTV coverage. With proposed planning objectives, this is translated into minimizing three mean-tail-doses. Comparison with conventional objectives is carried out in the dose-at-volume domain and in the no...
3. Assessment tool for planning fallback Tomotherapy treatment plans; Evaluacion de la herramienta fallback planning para planes de tratamiento de tomoterapia
Energy Technology Data Exchange (ETDEWEB)
Sanchez Rubio, P.; Rodriguez Romero, R.; Montes Uruen, A.
2015-07-01
Interruption of radiotherapy treatments in an increase the total time of the same to the detriment of tumour control. In centers that have a unique special unit as the TomoTherapy, is emphasized the difficulty to resume treatment at another unit, since the technique of helical TomoTherapy is not portable to conventional accelerators and therefore requires the planning of new dosimetry distributions emulating the initially obtained and accepted. This work evaluates the ability of an automatic planning tool to mimic TomoTherapy plans. (Author)
4. USC-ABC ATMnet for radiation treatment planning
Science.gov (United States)
Shrivastava, Prakash N.; Petrovich, Zbigniew P.; Boswell, William D., Jr.; George, Frederick W., III; Chow, Edward T.
1996-05-01
Three dimensional visualization of tumor and normal tissues are often valuable in precision treatment planning for radiation therapy of cancer. This is often not possible in many remote treatment facilities because of the high cost of imaging and computer equipment. At the University of Southern California, School of Medicine we are developing and testing a high speed, wide area, computer communications network to provide access to such resources from remote locations. In this paper, we present our concept of a Virtual Academic Medical Center, our network design and report on initial evaluations of effectiveness and clinical acceptability of 3D, CT simulation and treatment planning from a distance.
5. A study of computational dosimetry and boron biodistribution for ex – situ lung BNCT at RA-3 Reactor
International Nuclear Information System (INIS)
Within the context of the preclinical ex-situ BNCT Project for the treatment of diffuse lung metastases, we performed boron biodistribution studies in a sheep model and computational dosimetry studies in human lung to evaluate the potential therapeutic efficacy of the proposed technique. Herein we report preliminary data that supports the use of the sheep model as an adequate human surrogate in terms of boron kinetics and uptake in clinically relevant tissues. Furthermore, the estimation of the potential therapeutic efficacy of the proposed treatment in humans, based on boron uptake values in the large animal model, yields promising tumor control probability values even in the most conservative scenario considered. (author)
6. Boron neutron capture therapy for the treatment of oral cancer in the hamster cheek pouch model
International Nuclear Information System (INIS)
We have proposed and validated the hamster cheek pouch model of oral cancer for BNCT studies separately. We herein report the first evidence of the usefulness of BNCT for the treatment of oral cancer in an experimental model. We assessed the response of hamster cheek pouch tumors, precancerous tissue and normal oral tissue to BPA-mediated BNCT employing the thermalized epithermal beam of the RA-6 Reactor at the Bariloche Atomic Center. BNCT leads to complete remission by 15 days post-treatment in 78% of tumors and partial remission in a further 13% of tumors with virtually no damage to normal tissue. (author)
7. Comparative study of conformal versus intensity modulated radiotherapy treatment plans
International Nuclear Information System (INIS)
Full text: In order to establish some early clinical experience in the use of intensity modulated radiotherapy (IMRT) as an alternative treatment method to conformal irradiation, we selected a number of specifically difficult clinical cases to compare. Complex tumour shapes located in the skull (two cases), close to the spinal cord (two cases) and one standard prostate case were chosen for this study. A Varian CadPlan system is used for the conformal treatment plans and Helios for the IMRT plans. In both these techniques, the linear accelerator multileaf collimator system is used to shape the beam about the target volume. The Royal North Shore Hospital Varian Clinac 600C/D linear accelerator also has dynamic multileaf collimator control (DMLC) capabilities for IMRT. The five cases reported here were planned by the radiation therapists for conformal treatment and then re-planned by physics using the CadPlan's Helios inverse planning option to produce an alternative IMRT plan. Both planners worked independently of each other. Treatment set-up errors were not considered as part of this study but it is apparent here that positional errors and immobilisation are particularly important factors to consider. An allowance for all errors must therefore be included for all critical organ outlines as well as the target volume for both the conformal or IMRT treatments. Visually, the covering of regularly shaped treatment volumes for the IMRT plans was improved marginally over the conformal plan. However, complex treatment volumes (such as the posterior orbital region with surrounding critical structures) showed very clear improvements. The IMRT dose drop-off at the edge of the target volume was not as sharp as the conformal equivalent. The dose-volume-histogram (DVH) provides a limited analytical tool to quantify these observations. The DVH generally indicated similar curves for the IMRT and conformal target volume but significant IMRT improvements in limiting the dose to
8. Knowledge-based radiation therapy (KBRT) treatment planning versus planning by experts: validation of a KBRT algorithm for prostate cancer treatment planning
International Nuclear Information System (INIS)
A knowledge-based radiation therapy (KBRT) treatment planning algorithm was recently developed. The purpose of this work is to investigate how plans that are generated with the objective KBRT approach compare to those that rely on the judgment of the experienced planner. Thirty volumetric modulated arc therapy plans were randomly selected from a database of prostate plans that were generated by experienced planners (expert plans). The anatomical data (CT scan and delineation of organs) of these patients and the KBRT algorithm were given to a novice with no prior treatment planning experience. The inexperienced planner used the knowledge-based algorithm to predict the dose that the OARs receive based on their proximity to the treated volume. The population-based OAR constraints were changed to the predicted doses. A KBRT plan was subsequently generated. The KBRT and expert plans were compared for the achieved target coverage and OAR sparing. The target coverages were compared using the Uniformity Index (UI), while 5 dose-volume points (D10, D30, D50, D70 and D90) were used to compare the OARs (bladder and rectum) doses. Wilcoxon matched-pairs signed rank test was used to check for significant differences (p < 0.05) between both datasets. The KBRT and expert plans achieved mean UI values of 1.10 ± 0.03 and 1.10 ± 0.04, respectively. The Wilcoxon test showed no statistically significant difference between both results. The D90, D70, D50, D30 and D10 values of the two planning strategies, and the Wilcoxon test results suggests that the KBRT plans achieved a statistically significant lower bladder dose (at D30), while the expert plans achieved a statistically significant lower rectal dose (at D10 and D30). The results of this study show that the KBRT treatment planning approach is a promising method to objectively incorporate patient anatomical variations in radiotherapy treatment planning
9. Microwave digestion techniques applied to determination of boron by ICP-AES in BNCT program
International Nuclear Information System (INIS)
Recently, boron neutron capture therapy (BNCT) has merged as an interesting option for the treatment of some kind of tumors where established therapies show no success. A molecular boronated species, enriched in 10B is administrated to the subject; it localizes in malignant tissues depending the kind of tumor and localization. Therefore, a very important fact in BNCT research is the detection of boron at trace or ultra trace levels precisely and accurately. This is extremely necessary as boronated species do localize in tumoral tissue and also localize in liver, kidney, spleen, skin, membranes. By this way, before testing a boronated species, it is mandatory to determine its biodistribution in a statistically meaning population, that is related with managing of a great number of samples. In the other hand, it is necessary to exactly predict when to begin the irradiation and to determine the magnitude of radiation to obtain the desired radiological dose for a specified mean boron concentration. This involves the determination of boron in whole blood, which is related with boron concentration in the tumor object of treatment. The methodology selected for the analysis of boron in whole blood and tissues must join certain characteristics: it must not be dependant of the chemical form of boron, it has to be fast and capable to determine boron accurately and precisely in a wide range of concentrations. The design and validation of experimental models involving animals in BNCT studies and the determination of boron in blood of animals and subjects upon treatment require reliable analytical procedures to determine boron quantitatively in those biologic materials. Inductively coupled plasma-atomic emission spectrometry (ICP-AES) using pneumatic nebulization is one of the most promising methods for boron analysis, but the sample must be liquid and have low solid concentration. In our case, biological tissues and blood, it is mandatory to mineralize and/or dilute samples
10. Initial application of digital tomosynthesis to improve brachytherapy treatment planning
Science.gov (United States)
Baydush, Alan H.; Mirzaei McKee, Mahta; King, June; Godfrey, Devon J.
2007-03-01
We present preliminary investigations that examine the feasibility of incorporating volumetric images generated using digital tomosynthesis into brachytherapy treatment planning. The Integrated Brachytherapy Unit (IBU) at our facility consists of an L-arm, C-arm isocentric motion system with an x-ray tube and fluoroscopic imager attached. Clinically, this unit is used to generate oblique, anterior-posterior, and lateral images for simple treatment planning and dose prescriptions. Oncologists would strongly prefer to have volumetric data to better determine three dimensional dose distributions (dose-volume histograms) to the target area and organs at risk. Moving the patient back and forth to CT causes undo stress on the patient, allows extensive motion of organs and treatment applicators, and adds additional time to patient treatment. We propose to use the IBU imaging system with digital tomosynthesis to generate volumetric patient data, which can be used for improving treatment planning and overall reducing treatment time. Initial image data sets will be acquired over a limited arc of a human-like phantom composed of real bones and tissue equivalent material. A brachytherapy applicator will be incorporated into one of the phantoms for visualization purposes. Digital tomosynthesis will be used to generate a volumetric image of this phantom setup. This volumetric image set will be visually inspected to determine the feasibility of future incorporation of these types of images into brachytherapy treatment planning. We conclude that initial images using the tomosynthesis reconstruction technique show much promise and bode well for future work.
11. Standardized treatment planning methodology for passively scattered proton craniospinal irradiation
International Nuclear Information System (INIS)
As the number of proton therapy centers increases, so does the need for studies which compare proton treatments between institutions and with photon therapy. However, results of such studies are highly dependent on target volume definition and treatment planning techniques. Thus, standardized methods of treatment planning are needed, particularly for proton treatment planning, in which special consideration is paid to the depth and sharp distal fall-off of the proton distribution. This study presents and evaluates a standardized method of proton treatment planning for craniospinal irradiation (CSI). We applied our institution’s planning methodology for proton CSI, at the time of the study, to an anatomically diverse population of 18 pediatric patients. We evaluated our dosimetric results for the population as a whole and for the two subgroups having two different age-specific target volumes using the minimum, maximum, and mean dose values in 10 organs (i.e., the spinal cord, brain, eyes, lenses, esophagus, lungs, kidneys, thyroid, heart, and liver). We also report isodose distributions and dose-volume histograms (DVH) for 2 representative patients. Additionally we report population-averaged DVHs for various organs. The planning methodology here describes various techniques used to achieve normal tissue sparing. In particular, we found pronounced dose reductions in three radiosensitive organs (i.e., eyes, esophagus, and thyroid) which were identified for optimization. Mean doses to the thyroid, eyes, and esophagus were 0.2%, 69% and 0.2%, respectively, of the prescribed dose. In four organs not specifically identified for optimization (i.e., lungs, liver, kidneys, and heart) we found that organs lateral to the treatment field (lungs and kidneys) received relatively low mean doses (less than 8% of the prescribed dose), whereas the heart and liver, organs distal to the treatment field, received less than 1% of the prescribed dose. This study described and evaluated
12. Power Burst Facility/Boron Neutron Capture Therapy Program for cancer treatment
Energy Technology Data Exchange (ETDEWEB)
Ackermann, A.L. (ed.); Dorn, R.V. III.
1990-08-01
This report discusses monthly progress in the Power Boron Facility/Boron Neutron Capture Therapy (PBF/BNCT) Program for Cancer Treatment. Highlights of the PBF/BNCT Program during August 1990 include progress within the areas of: Gross Boron Analysis in Tissue, Blood, and Urine, boron microscopic (subcellular) analytical development, noninvasive boron quantitative determination, analytical radiation transport and interaction modeling for BNCT, large animal model studies, neutron source and facility preparation, administration and common support and PBF operations.
13. Optimization of the application of BNCT to undifferentiated thyroid cancer
International Nuclear Information System (INIS)
The possible increase in BNCT efficacy for undifferentiated thyroid carcinoma (UTC) using BPA plus BOPP and nicotinamide (NA) as a radiosensitizer on the BNCT reaction was analyzed. In these studies nude mice were transplanted with the ARO cells and after 14 days they were treated as follows: 1) Control; 2) NCT (neutrons alone); 3) NCT plus NA (100 mg/kg bw/day for 3 days); 4) BPA (350 mg/kg bw) + neutrons; 5) BPA+ NA+ neutrons; 6) BPA+BOPP (60 mg/kg bw) + neutrons. The flux of hyperthermal neutrons was 2.8 108 during 85 min. Neutrons alone or with NA caused some tumor growth delay, while in the BPA, BPA+NA and BPA+BOPP groups a 100% halt of tumor growth was observed. When the initial tumor volume was 50 mm3 or less a complete cure was found in BPA+NA (2/2); BPA (1/4); BPA+BOPP (7/7). After 90 days of complete regression, recurrence of tumor was observed in 2/2 BPA/NA (2/2) and BPA+BOPP (1/7). Caspase 3 activity was increased in BPA+NA (p<0.05 vs controls). BPA plus NA increased tumor apoptosis but only the combination of BPA+BOPP increased significantly BNCT efficiency. (author)
14. Clinical results of BNCT for malignant brain tumors in children
Energy Technology Data Exchange (ETDEWEB)
Nakagawa, Yoshinobu [Department of Neurosurgery, Kagawa National Children' s Hospital, Kagawa 765-8501 (Japan)], E-mail: [email protected]; Kageji, Teruyoshi; Mizobuchi, Yoshifumi [Department of Neurosurgery, University of Tokushima, Tokushima 770-8503 (Japan); Kumada, Hiroaki [Department of Research Reactor, Japan Atomic Energy Research Institute, Ibaragi 319-1195 (Japan); Nakagawa, Yoshiaki [Department of Medical Informatics, Post Graduated School, Kyoto University, Kyoto (Japan)
2009-07-15
It is very difficult to treat the patients with malignant brain tumor in children, especially under 3 years, because the conventional irradiation cannot be applied due to the damage of normal brain tissue. However, boron neutron capture therapy (BNCT) has tumor selectivity such that it can make damage only in tumor cells. We evaluated the clinical results and courses in patients with malignant glioma under 15 years. Among 183 patients with brain tumors treated by our group using BSH-based intra-operative BNCT, 23 patients were under 15 years. They included 4 patients under 3 years. There were 3 glioblastomas (GBM), 6 anaplastic astrocytomas(AAS), 7 primitive neuroectodermal tumors (PNET), 6 pontine gliomas and 1 anaplastic ependymoma. All GBM and PNET patients died due to CSF and/or CNS dissemination without local tumor regrowth. All pontine glioma patients died due to regrowth of the tumor. Four of 6 anaplastic astrocytoma and 1 anaplastic ependymoma patients alive without tumor recurrence. BNCT can be applied to malignant brain tumors in children, especially under 3 years instead of conventional radiation. Although it can achieve the local control in the primary site, it cannot prevent CSF dissemination in patients with glioblastoma.
15. IMRT treatment plans and functional planning with functional lung imaging from 4D-CT for thoracic cancer patients
OpenAIRE
Huang Tzung-Chi; Hsiao Chien-Yi; Chien Chun-Ru; Liang Ji-An; Shih Tzu-Ching; Zhang Geoffrey G
2013-01-01
Abstract Background and purpose Currently, the inhomogeneity of the pulmonary function is not considered when treatment plans are generated in thoracic cancer radiotherapy. This study evaluates the dose of treatment plans on highly-functional volumes and performs functional treatment planning by incorporation of ventilation data from 4D-CT. Materials and methods Eleven patients were included in this retrospective study. Ventilation was calculated using 4D-CT. Two treatment plans were generate...
16. Sampling and Analysis Plan - Waste Treatment Plant Seismic Boreholes Project
Energy Technology Data Exchange (ETDEWEB)
Reidel, Steve P.
2006-05-26
This sampling and analysis plan (SAP) describes planned data collection activities for four entry boreholes through the sediment overlying the basalt, up to three new deep rotary boreholes through the basalt and sedimentary interbeds, and one corehole through the basalt and sedimentary interbeds at the Waste Treatment Plant (WTP) site. The SAP will be used in concert with the quality assurance plan for the project to guide the procedure development and data collection activities needed to support borehole drilling, geophysical measurements, and sampling. This SAP identifies the American Society of Testing Materials standards, Hanford Site procedures, and other guidance to be followed for data collection activities.
17. Comparison of the radiobiological effects of Boron neutron capture therapy (BNCT) and conventional Gamma Radiation
International Nuclear Information System (INIS)
BNCT is an experimental radiotherapeutic modality that uses the capacity of the isotope 10B to capture thermal neutrons leading to the production of 4He and 7Li, particles with high linear energy transfer (LET). The aim was to evaluate and compare in vitro the mechanisms of response to the radiation arising of BNCT and conventional gamma therapy. We measured the survival cell fraction as a function of the total physical dose and analyzed the expression of p27/Kip1 and p53 by Western blotting in cells of colon cancer (ARO81-1). Exponentially growing cells were distributed into the following groups: 1) BPA (10 ppm 10B) + neutrons; 2) BOPP (10 ppm 10B) + neutrons; 3) neutrons alone; 4) gamma-rays. A control group without irradiation for each treatment was added. The cells were irradiated in the thermal neutron beam of the RA-3 (flux= 7.5 109 n/cm2 sec) or with 60Co (1Gy/min) during different times in order to obtain total physical dose between 1-5 Gy (±10 %). A decrease in the survival fraction as a function of the physical dose was observed for all the treatments. We also observed that neutrons and neutrons + BOPP did not differ significantly and that BPA was the more effective compound. Protein extracts of irradiated cells (3Gy) were isolated to 24 h and 48 h post radiation exposure. The irradiation with neutrons in presence of 10BPA or 10BOPP produced an increase of p53 at 24 h maintain until 48 h. On the contrary, in the groups irradiated with neutrons alone or gamma the peak was observed at 48 hr. The level of expression of p27/Kip1 showed a reduction of this protein in all the groups irradiated with neutrons (neutrons alone or neutrons plus boron compound), being more marked at 24 h. These preliminary results suggest different radiobiological response for high and low let radiation. Future studies will permit establish the role of cell cycle in the tumor radio sensibility to BNCT. (author)
18. Orthognathic Surgery: Planning and treatment with illustration on six cases
International Nuclear Information System (INIS)
Almost all conferences for plastic and maxillofacial surgery discuss reports on several methods of orthognathic surgery, planning, success results, and complications of the different procedures carried out to correct patient's soft and hard tissues frontal profiles and occlusal discrepancies. Various principles are involved in the diagnosis and treatment of facial deformities. However, the most important consideration, after all, is the final accepted aesthetic and functional requirements and stability of the moved segments. The objective of this paper is to give the basic principles of treatment planning for correcting facial discrepancies, surgical approach to different cases, and the methods to increase stability of the moved segments. Six cases are included to illustrate the different aspects of treatment planning, surgical management, and stabilization methods. (author)
19. SU-D-BRD-03: Improving Plan Quality with Automation of Treatment Plan Checks
Energy Technology Data Exchange (ETDEWEB)
Covington, E; Younge, K; Chen, X; Lee, C; Matuszak, M; Kessler, M; Acosta, E; Orow, A; Filpansick, S; Moran, J [University of Michigan Hospital and Health System, Ann Arbor, MI (United States); Keranen, W [Varian Medical Systems, Palo Alto, CA (United States)
2015-06-15
Purpose: To evaluate the effectiveness of an automated plan check tool to improve first-time plan quality as well as standardize and document performance of physics plan checks. Methods: The Plan Checker Tool (PCT) uses the Eclipse Scripting API to check and compare data from the treatment planning system (TPS) and treatment management system (TMS). PCT was created to improve first-time plan quality, reduce patient delays, increase efficiency of our electronic workflow, and to standardize and partially automate plan checks in the TPS. A framework was developed which can be configured with different reference values and types of checks. One example is the prescribed dose check where PCT flags the user when the planned dose and the prescribed dose disagree. PCT includes a comprehensive checklist of automated and manual checks that are documented when performed by the user. A PDF report is created and automatically uploaded into the TMS. Prior to and during PCT development, errors caught during plan checks and also patient delays were tracked in order to prioritize which checks should be automated. The most common and significant errors were determined. Results: Nineteen of 33 checklist items were automated with data extracted with the PCT. These include checks for prescription, reference point and machine scheduling errors which are three of the top six causes of patient delays related to physics and dosimetry. Since the clinical roll-out, no delays have been due to errors that are automatically flagged by the PCT. Development continues to automate the remaining checks. Conclusion: With PCT, 57% of the physics plan checklist has been partially or fully automated. Treatment delays have declined since release of the PCT for clinical use. By tracking delays and errors, we have been able to measure the effectiveness of automating checks and are using this information to prioritize future development. This project was supported in part by P01CA059827.
20. Boron neutron capture therapy as new treatment for clear cell sarcoma: Trial on different animal model
International Nuclear Information System (INIS)
Clear cell sarcoma (CCS) is a rare malignant tumor with a poor prognosis. In our previous study, the tumor disappeared under boron neutron capture therapy (BNCT) on subcutaneously-transplanted CCS-bearing animals. In the present study, the tumor disappeared under this therapy on model mice intramuscularly implanted with three different human CCS cells. BNCT led to the suppression of tumor-growth in each of the different model mice, suggesting its potentiality as an alternative to, or integrative option for, the treatment of CCS. - Highlights: • BNCT with the use of L-BPA was applied for three human clear cell sarcoma (CCS) cell lines. • BNCT trial was performed on a newly established intramuscularly CCS-bearing animal model. • A significant decrease of the tumor-volume was seen by single BNCT with the use of L-BPA. • A multiple BNCT application would be required for controlling the growth of any residual tumors
1. IMRT treatment plans and functional planning with functional lung imaging from 4D-CT for thoracic cancer patients
Directory of Open Access Journals (Sweden)
Huang Tzung-Chi
2013-01-01
Full Text Available Abstract Background and purpose Currently, the inhomogeneity of the pulmonary function is not considered when treatment plans are generated in thoracic cancer radiotherapy. This study evaluates the dose of treatment plans on highly-functional volumes and performs functional treatment planning by incorporation of ventilation data from 4D-CT. Materials and methods Eleven patients were included in this retrospective study. Ventilation was calculated using 4D-CT. Two treatment plans were generated for each case, the first one without the incorporation of the ventilation and the second with it. The dose of the first plans was overlapped with the ventilation and analyzed. Highly-functional regions were avoided in the second treatment plans. Results For small targets in the first plans (PTV Conclusion Radiation treatments affect functional lung more seriously in large tumor cases. With compromise of dose to other critical organs, functional treatment planning to reduce dose in highly-functional lung volumes can be achieved
2. Neuro-Dynamic Programming for Radiation Treatment Planning
OpenAIRE
Ferris, Michael C.; Voelker, Meta M.
2002-01-01
In many cases a radiotherapy treatment is delivered as a series of smaller dosages over a period of time. Currently, it is difficult to determine the actual dose that has been delivered at each stage, precluding the use of adaptive treatment plans. However, new generations of machines will give more accurate information of actual dose delivered, allowing a planner to compensate for errors in delivery. We formulate a model of the day-to-day planning problem as a stochastic linear program and e...
3. Confirmation of a realistic reactor model for BNCT dosimetry at the TRIGA Mainz
Energy Technology Data Exchange (ETDEWEB)
Ziegner, Markus, E-mail: [email protected] [AIT Austrian Institute of Technology GmbH, Vienna A-1220, Austria and Institute of Atomic and Subatomic Physics, Vienna University of Technology, Vienna A-1020 (Austria); Schmitz, Tobias; Hampel, Gabriele [Institut für Kernchemie, Johannes Gutenberg-Universität, Mainz DE-55128 (Germany); Khan, Rustam [Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad PK-44000 (Pakistan); Blaickner, Matthias [AIT Austrian Institute of Technology GmbH, Vienna A-1220 (Austria); Palmans, Hugo [Acoustics and Ionising Radiation Division, National Physical Laboratory, Teddington TW11 0LW, United Kingdom and Medical Physics Group, EBG MedAustron GmbH, Wiener Neustadt A-2700 (Austria); Sharpe, Peter [Acoustics and Ionising Radiation Division, National Physical Laboratory, Teddington TW11 0LW (United Kingdom); Böck, Helmuth [Institute of Atomic and Subatomic Physics, Vienna University of Technology, Vienna A-1020 (Austria)
2014-11-01
Purpose: In order to build up a reliable dose monitoring system for boron neutron capture therapy (BNCT) applications at the TRIGA reactor in Mainz, a computer model for the entire reactor was established, simulating the radiation field by means of the Monte Carlo method. The impact of different source definition techniques was compared and the model was validated by experimental fluence and dose determinations. Methods: The depletion calculation code ORIGEN2 was used to compute the burn-up and relevant material composition of each burned fuel element from the day of first reactor operation to its current core. The material composition of the current core was used in a MCNP5 model of the initial core developed earlier. To perform calculations for the region outside the reactor core, the model was expanded to include the thermal column and compared with the previously established ATTILA model. Subsequently, the computational model is simplified in order to reduce the calculation time. Both simulation models are validated by experiments with different setups using alanine dosimetry and gold activation measurements with two different types of phantoms. Results: The MCNP5 simulated neutron spectrum and source strength are found to be in good agreement with the previous ATTILA model whereas the photon production is much lower. Both MCNP5 simulation models predict all experimental dose values with an accuracy of about 5%. The simulations reveal that a Teflon environment favorably reduces the gamma dose component as compared to a polymethyl methacrylate phantom. Conclusions: A computer model for BNCT dosimetry was established, allowing the prediction of dosimetric quantities without further calibration and within a reasonable computation time for clinical applications. The good agreement between the MCNP5 simulations and experiments demonstrates that the ATTILA model overestimates the gamma dose contribution. The detailed model can be used for the planning of structural
4. Draft Site Treatment Plan (DSTP), Volumes I and II
International Nuclear Information System (INIS)
Site Treatment Plans (STP) are required for facilities at which the DOE generates or stores mixed waste. This Draft Site Treatment Plan (DSTP) the second step in a three-phase process, identifies the currently preferred options for treating mixed waste at the Savannah River Site (SRS) or for developing treatment technologies where technologies do not exist or need modification. The DSTP reflects site-specific preferred options, developed with the state's input and based on existing available information. To the extent possible, the DSTP identifies specific treatment facilities for treating the mixed waste and proposes schedules. Where the selection of specific treatment facilities is not possible, schedules for alternative activities such as waste characterization and technology assessment are provided. All schedule and cost information presented is preliminary and is subject to change. The DSTP is comprised of two volumes: this Compliance Plan Volume and the Background Volume. This Compliance Plan Volume proposes overall schedules with target dates for achieving compliance with the land disposal restrictions (LDR) of RCRA and procedures for converting the target dates into milestones to be enforced under the Order. The more detailed discussion of the options contained in the Background Volume is provided for informational purposes only
5. Draft Site Treatment Plan (DSTP), Volumes I and II
Energy Technology Data Exchange (ETDEWEB)
DAmelio, J.
1994-08-30
Site Treatment Plans (STP) are required for facilities at which the DOE generates or stores mixed waste. This Draft Site Treatment Plan (DSTP) the second step in a three-phase process, identifies the currently preferred options for treating mixed waste at the Savannah River Site (SRS) or for developing treatment technologies where technologies do not exist or need modification. The DSTP reflects site-specific preferred options, developed with the states input and based on existing available information. To the extent possible, the DSTP identifies specific treatment facilities for treating the mixed waste and proposes schedules. Where the selection of specific treatment facilities is not possible, schedules for alternative activities such as waste characterization and technology assessment are provided. All schedule and cost information presented is preliminary and is subject to change. The DSTP is comprised of two volumes: this Compliance Plan Volume and the Background Volume. This Compliance Plan Volume proposes overall schedules with target dates for achieving compliance with the land disposal restrictions (LDR) of RCRA and procedures for converting the target dates into milestones to be enforced under the Order. The more detailed discussion of the options contained in the Background Volume is provided for informational purposes only.
6. Novel tools for stepping source brachytherapy treatment planning: Enhanced geometrical optimization and interactive inverse planning
Energy Technology Data Exchange (ETDEWEB)
Dinkla, Anna M., E-mail: [email protected]; Laarse, Rob van der; Koedooder, Kees; Petra Kok, H.; Wieringen, Niek van; Pieters, Bradley R.; Bel, Arjan [Department of Radiation Oncology, Academic Medical Center Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ (Netherlands)
2015-01-15
Purpose: Dose optimization for stepping source brachytherapy can nowadays be performed using automated inverse algorithms. Although much quicker than graphical optimization, an experienced treatment planner is required for both methods. With automated inverse algorithms, the procedure to achieve the desired dose distribution is often based on trial-and-error. Methods: A new approach for stepping source prostate brachytherapy treatment planning was developed as a quick and user-friendly alternative. This approach consists of the combined use of two novel tools: Enhanced geometrical optimization (EGO) and interactive inverse planning (IIP). EGO is an extended version of the common geometrical optimization method and is applied to create a dose distribution as homogeneous as possible. With the second tool, IIP, this dose distribution is tailored to a specific patient anatomy by interactively changing the highest and lowest dose on the contours. Results: The combined use of EGO–IIP was evaluated on 24 prostate cancer patients, by having an inexperienced user create treatment plans, compliant to clinical dose objectives. This user was able to create dose plans of 24 patients in an average time of 4.4 min/patient. An experienced treatment planner without extensive training in EGO–IIP also created 24 plans. The resulting dose-volume histogram parameters were comparable to the clinical plans and showed high conformance to clinical standards. Conclusions: Even for an inexperienced user, treatment planning with EGO–IIP for stepping source prostate brachytherapy is feasible as an alternative to current optimization algorithms, offering speed, simplicity for the user, and local control of the dose levels.
7. The status of Tsukuba BNCT trial: BPA-based boron neutron capture therapy combined with X-ray irradiation
Energy Technology Data Exchange (ETDEWEB)
Yamamoto, T., E-mail: [email protected] [Department of Neurosurgery, Graduate School of Comprehensive Human Science, University of Tsukuba, Tennodai 1-1-1, Tsukuba (Japan)] [Department of Radiation Oncology, Graduate School of Comprehensive Human Science, University of Tsukuba, Tennodai 1-1-1, Tsukuba (Japan); Nakai, K. [Department of Neurosurgery, Graduate School of Comprehensive Human Science, University of Tsukuba, Tennodai 1-1-1, Tsukuba (Japan); Nariai, T. [Department of Neurosurgery, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo (Japan); Kumada, H.; Okumura, T.; Mizumoto, M.; Tsuboi, K. [Department of Radiation Oncology, Graduate School of Comprehensive Human Science, University of Tsukuba, Tennodai 1-1-1, Tsukuba (Japan); Zaboronok, A.; Ishikawa, E.; Aiyama, H.; Endo, K.; Takada, T.; Yoshida, F.; Shibata, Y.; Matsumura, A. [Department of Neurosurgery, Graduate School of Comprehensive Human Science, University of Tsukuba, Tennodai 1-1-1, Tsukuba (Japan)
2011-12-15
The phase II trial has been prepared to assess the effectiveness of BPA (250 mg/kg)-based NCT combined with X-ray irradiation and temozolomide (75 mg/m{sup 2}) for the treatment of newly diagnosed GBM. BPA uptake is determined by {sup 18}F-BPA-PET and/or {sup 11}C-MET-PET, and a tumor with the lesion to normal ratio of 2 or more is indicated for BNCT. The maximum normal brain point dose prescribed was limited to 13.0 Gy or less. Primary end point is overall survival.
8. Development and validation of a treatment planning system for small animal radiotherapy: SmART-Plan
International Nuclear Information System (INIS)
Background and purpose: Image-guided equipment for precision irradiation of small animals for pre-clinical radiotherapy research became recently available. To enable downscaled radiotherapy studies that can be translated into human radiotherapy knowledge, a treatment planning system for pre-clinical studies is required. Material and methods: A dedicated treatment planning system (SmART-Plan) for small animal radiotherapy studies was developed. It is based on Monte Carlo simulation of particle transport in an animal. The voxel geometry is derived from the onboard cone beam CT imaging panel. SmART-Plan was validated using radiochromic film (RCF) dosimetry in various phantoms: uniform, multislab and a realistic plasticized mouse geometry. Results: Good agreement was obtained between SmART-Plan dose calculations and RCF dose measurements in all phantoms. For various delivered plans agreement was obtained within 10% for the majority of the targeted dose region, with larger differences between 10% and 20% near the penumbra regions and for the smallest 1 mm collimator. Absolute depth and lateral dose distributions showed better agreement for 5 and 15-mm collimators than for a 1-mm collimator, indicating that accurate dose prediction for the smallest field sizes is difficult. Conclusion: SmART-Plan offers a useful dose calculation tool for pre-clinical small animal irradiation studies
9. Analysis of accelerator based neutron spectra for BNCT using proton recoil spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Wielopolski, L.; Ludewig, H.; Powell, J.R.; Raparia, D.; Alessi, J.G.; Lowenstein, D.I.
1999-03-01
Boron Neutron Capture Therapy (BNCT) is a promising binary treatment modality for high-grade primary brain tumors (glioblastoma multiforme, GM) and other cancers. BNCT employs a boron-10 containing compound that preferentially accumulates in the cancer cells in the brain. Upon neutron capture by {sup 10}B energetic alpha particles and triton released at the absorption site kill the cancer cell. In order to gain penetration depth in the brain Fairchild proposed, for this purpose, the use of energetic epithermal neutrons at about 10 keV. Phase 1/2 clinical trials of BNCT for GM are underway at the Brookhaven Medical Research Reactor (BMRR) and at the MIT Reactor, using these nuclear reactors as the source for epithermal neutrons. In light of the limitations of new reactor installations, e.g. cost, safety and licensing, and limited capability for modulating the reactor based neutron beam energy spectra, alternative neutron sources are being contemplated for wider implementation of this modality in a hospital environment. For example, accelerator based neutron sources offer the possibility of tailoring the neutron beams, in terms of improved depth-dose distributions, to the individual and offer, with relative ease, the capability of modifying the neutron beam energy and port size. In previous work new concepts for compact accelerator/target configuration were published. In this work, using the Van de Graaff accelerator the authors have explored different materials for filtering and reflecting neutron beams produced by irradiating a thick Li target with 1.8 to 2.5 MeV proton beams. However, since the yield and the maximum neutron energy emerging from the Li-7(p,n)Be-7 reaction increase with increase in the proton beam energy, there is a need for optimization of the proton energy versus filter and shielding requirements to obtain the desired epithermal neutron beam. The MCNP-4A computer code was used for the initial design studies that were verified with benchmark
10. ANALYSIS OF ACCELERATOR BASED NEUTRON SPECTRA FOR BNCT USING PROTON RECOIL SPECTROSCOPY
Energy Technology Data Exchange (ETDEWEB)
WIELOPOLSKI,L.; LUDEWIG,H.; POWELL,J.R.; RAPARIA,D.; ALESSI,J.G.; LOWENSTEIN,D.I.
1998-11-06
Boron Neutron Capture Therapy (BNCT) is a promising binary treatment modality for high-grade primary brain tumors (glioblastoma multiforme, GM) and other cancers. BNCT employs a boron-10 containing compound that preferentially accumulates in the cancer cells in the brain. Upon neutron capture by {sup 10}B energetic alpha particles and triton released at the absorption site kill the cancer cell. In order to gain penetration depth in the brain Fairchild proposed, for this purpose, the use of energetic epithermal neutrons at about 10 keV. Phase I/II clinical trials of BNCT for GM are underway at the Brookhaven Medical Research Reactor (BMRR) and at the MIT Reactor, using these nuclear reactors as the source for epithermal neutrons. In light of the limitations of new reactor installations, e.g. cost, safety and licensing, and limited capability for modulating the reactor based neutron beam energy spectra alternative neutron sources are being contemplated for wider implementation of this modality in a hospital environment. For example, accelerator based neutron sources offer the possibility of tailoring the neutron beams, in terms of improved depth-dose distributions, to the individual and offer, with relative ease, the capability of modifying the neutron beam energy and port size. In previous work new concepts for compact accelerator/target configuration were published. In this work, using the Van de Graaff accelerator the authors have explored different materials for filtering and reflecting neutron beams produced by irradiating a thick Li target with 1.8 to 2.5 MeV proton beams. However, since the yield and the maximum neutron energy emerging from the Li-7(p,n)Be-7 reaction increase with increase in the proton beam energy, there is a need for optimization of the proton energy versus filter and shielding requirements to obtain the desired epithermal neutron beam. The MCNP-4A computer code was used for the initial design studies that were verified with benchmark
11. A treatment planning study comparing Elekta VMAT and fixed field IMRT using the varian treatment planning system eclipse
International Nuclear Information System (INIS)
The newest release of the Eclipse (Varian) treatment planning system (TPS) includes an optimizing engine for Elekta volumetric-modulated arc therapy (VMAT) planning. The purpose of this study was to evaluate this new algorithm and to compare it to intensity-modulated radiation therapy (IMRT) for various disease sites by creating single- and double-arc VMAT plans. A total of 162 plans were evaluated in this study, including 38 endometrial, 57 head and neck, 12 brain, 10 breast and 45 prostate cancer cases. The real-life IMRT plans were developed during routine clinical cases using the TPS Eclipse. VMAT plans were generated using a preclinical version of Eclipse with tumor-region-specific optimizing templates without interference of the operator: with one full arc (1A) and with two full arcs (2A), and with partial arcs for breast and prostate with hip implant cases. All plans were evaluated based on target coverage, homogeneity and conformity. The organs at risk (OARs) were analyzed according to plan objectives, such as the mean and maximum doses. If one or more objectives were exceeded, the plan was considered clinically unacceptable, and a second VMAT plan was created by adapting the optimization penalties once. Compared to IMRT, single- and double-arc VMAT plans showed comparable or better results concerning the target coverage: the maximum dose in the target for 1A is the same as that for IMRT; for 2A, an average reduction of 1.3% over all plans was observed. The conformity showed a statistically significant improvement for both 1A (+3%) and 2A (+6%). The mean total body dose was statistically significant lower for the considered arc techniques (IMRT: 16.0 Gy, VMAT: 15.3 Gy, p < 0.001). However, the sparing of OARs shows individual behavior that depends strongly on the different tumor regions. A clear difference is found in the number of monitor units (MUs) per plan: VMAT shows a reduction of 31%. These findings demonstrate that based on optimizing templates with
12. Demonstration of the importance of a dedicated neutron beam monitoring system for BNCT facility.
Science.gov (United States)
Chao, Der-Sheng; Liu, Yuan-Hao; Jiang, Shiang-Huei
2016-01-01
The neutron beam monitoring system is indispensable to BNCT facility in order to achieve an accurate patient dose delivery. The neutron beam monitoring of a reactor-based BNCT (RB-BNCT) facility can be implemented through the instrumentation and control system of a reactor provided that the reactor power level remains constant during reactor operation. However, since the neutron flux in reactor core is highly correlative to complicated reactor kinetics resulting from such as fuel depletion, poison production, and control blade movement, some extent of variation may occur in the spatial distribution of neutron flux in reactor core. Therefore, a dedicated neutron beam monitoring system is needed to be installed in the vicinity of the beam path close to the beam exit of the RB-BNCT facility, where it can measure the BNCT beam intensity as closely as possible and be free from the influence of the objects present around the beam exit. In this study, in order to demonstrate the importance of a dedicated BNCT neutron beam monitoring system, the signals originating from the two in-core neutron detectors installed at THOR were extracted and compared with the three dedicated neutron beam monitors of the THOR BNCT facility. The correlation of the readings between the in-core neutron detectors and the BNCT neutron beam monitors was established to evaluate the improvable quality of the beam intensity measurement inferred by the in-core neutron detectors. In 29 sampled intervals within 16 days of measurement, the fluctuations in the mean value of the normalized ratios between readings of the three BNCT neutron beam monitors lay within 0.2%. However, the normalized ratios of readings of the two in-core neutron detectors to one of the BNCT neutron beam monitors show great fluctuations of 5.9% and 17.5%, respectively. PMID:26595774
13. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan
International Nuclear Information System (INIS)
Since 1987, Westinghouse Hanford Company has been a major contractor to the U.S. Department of Energy-Richland Operations Office and has served as co-operator of the 3718-F Alkali Metal Treatment and Storage Facility, the waste management unit addressed in this closure plan. The closure plan consists of a Part A Dangerous waste Permit Application and a RCRA Closure Plan. An explanation of the Part A Revision (Revision 1) submitted with this document is provided at the beginning of the Part A section. The closure plan consists of 9 chapters and 5 appendices. The chapters cover: introduction; facility description; process information; waste characteristics; groundwater; closure strategy and performance standards; closure activities; postclosure; and references
14. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan
Energy Technology Data Exchange (ETDEWEB)
None
1991-12-01
Since 1987, Westinghouse Hanford Company has been a major contractor to the U.S. Department of Energy-Richland Operations Office and has served as co-operator of the 3718-F Alkali Metal Treatment and Storage Facility, the waste management unit addressed in this closure plan. The closure plan consists of a Part A Dangerous waste Permit Application and a RCRA Closure Plan. An explanation of the Part A Revision (Revision 1) submitted with this document is provided at the beginning of the Part A section. The closure plan consists of 9 chapters and 5 appendices. The chapters cover: introduction; facility description; process information; waste characteristics; groundwater; closure strategy and performance standards; closure activities; postclosure; and references.
15. [Endodontically treated teeth. Success--failure. Endorestorative treatment plan].
Science.gov (United States)
Zabalegui, B
1990-01-01
More and more often the general dentist is finding the presence of endodontically treated teeth during his treatment planning procedure. He has to ask himself if the endo-treated tooth functions and will continue to function function successfully, when deciding which final endo-restorative procedure to apply. For this reason the dentist or the endodontist with whom he works should clinically evaluate these teeth, establish a diagnostic criteria of their success or failure and a treatment plan according to the prognosis. The purpose of this article is to offer an organized clinical view of the steps to follow when evaluating an endodontically treated tooth and how to establish a final endo-restorative plan. PMID:2168732
16. [Endodontically treated teeth. Success--failure. Endorestorative treatment plan].
Science.gov (United States)
Zabalegui, B
1990-01-01
More and more often the general dentist is finding the presence of endodontically treated teeth during his treatment planning procedure. He has to ask himself if the endo-treated tooth functions and will continue to function function successfully, when deciding which final endo-restorative procedure to apply. For this reason the dentist or the endodontist with whom he works should clinically evaluate these teeth, establish a diagnostic criteria of their success or failure and a treatment plan according to the prognosis. The purpose of this article is to offer an organized clinical view of the steps to follow when evaluating an endodontically treated tooth and how to establish a final endo-restorative plan.
17. Savannah River Site Approved Site Treatment Plan, 1998 Annual Update
Energy Technology Data Exchange (ETDEWEB)
Lawrence, B.
1999-04-20
The Compliance Plan Volume (Volume I) identifies project activity schedule milestones for achieving compliance with Land Disposal Restrictions. Information regarding the technical evaluation of treatment options for SRS mixed wastes is contained in the Background Volume (Volume II) and is provided for information.
18. The effect of dose calculation accuracy on inverse treatment planning
Science.gov (United States)
Jeraj, Robert; Keall, Paul J.; Siebers, Jeffrey V.
2002-02-01
The effect of dose calculation accuracy during inverse treatment planning for intensity modulated radiotherapy (IMRT) was studied in this work. Three dose calculation methods were compared: Monte Carlo, superposition and pencil beam. These algorithms were used to calculate beamlets, which were subsequently used by a simulated annealing algorithm to determine beamlet weights which comprised the optimal solution to the objective function. Three different cases (lung, prostate and head and neck) were investigated and several different objective functions were tested for their effect on inverse treatment planning. It is shown that the use of inaccurate dose calculation introduces two errors in a treatment plan, a systematic error and a convergence error. The systematic error is present because of the inaccuracy of the dose calculation algorithm. The convergence error appears because the optimal intensity distribution for inaccurate beamlets differs from the optimal solution for the accurate beamlets. While the systematic error for superposition was found to be ~1% of Dmax in the tumour and slightly larger outside, the error for the pencil beam method is typically ~5% of Dmax and is rather insensitive to the given objectives. On the other hand, the convergence error was found to be very sensitive to the objective function, is only slightly correlated to the systematic error and should be determined for each case individually. Our results suggest that because of the large systematic and convergence errors, inverse treatment planning systems based on pencil beam algorithms alone should be upgraded either to superposition or Monte Carlo based dose calculations.
19. Including the Consumer and Environment in Occupational Therapy Treatment Planning.
Science.gov (United States)
Brown, Catana; Bowen, Robin E.
1998-01-01
Occupational therapists (n=29) completed treatment plans based on case study data. Analysis indicated they often identified goals not addressed by the consumer/client. They significantly selected more simulated than real activities and more activities designed to change the person rather than the environment. (SK)
20. Savannah River Site Approved Site Treatment Plan, 1998 Annual Update
International Nuclear Information System (INIS)
The Compliance Plan Volume (Volume I) identifies project activity schedule milestones for achieving compliance with Land Disposal Restrictions. Information regarding the technical evaluation of treatment options for SRS mixed wastes is contained in the Background Volume (Volume II) and is provided for information
1. Savannah River Site approved site treatment plan, 2000 annual update
International Nuclear Information System (INIS)
The Compliance Plan Volume (Volume 1) identifies project activity schedule milestones for achieving compliance with Land Disposal Restrictions. Information regarding the technical evaluation of treatment options for SRS mixed wastes is contained in the Background Volume (Volume 2) and is provided for information
2. Savannah River Site approved site treatment plan, 2000 annual update
Energy Technology Data Exchange (ETDEWEB)
Lawrence, B.
2000-04-20
The Compliance Plan Volume (Volume 1) identifies project activity schedule milestones for achieving compliance with Land Disposal Restrictions. Information regarding the technical evaluation of treatment options for SRS mixed wastes is contained in the Background Volume (Volume 2) and is provided for information.
3. Optimizing global liver function in radiation therapy treatment planning
Science.gov (United States)
Wu, Victor W.; Epelman, Marina A.; Wang, Hesheng; Romeijn, H. Edwin; Feng, Mary; Cao, Yue; Ten Haken, Randall K.; Matuszak, Martha M.
2016-09-01
Liver stereotactic body radiation therapy (SBRT) patients differ in both pre-treatment liver function (e.g. due to degree of cirrhosis and/or prior treatment) and radiosensitivity, leading to high variability in potential liver toxicity with similar doses. This work investigates three treatment planning optimization models that minimize risk of toxicity: two consider both voxel-based pre-treatment liver function and local-function-based radiosensitivity with dose; one considers only dose. Each model optimizes different objective functions (varying in complexity of capturing the influence of dose on liver function) subject to the same dose constraints and are tested on 2D synthesized and 3D clinical cases. The normal-liver-based objective functions are the linearized equivalent uniform dose (\\ell \\text{EUD} ) (conventional ‘\\ell \\text{EUD} model’), the so-called perfusion-weighted \\ell \\text{EUD} (\\text{fEUD} ) (proposed ‘fEUD model’), and post-treatment global liver function (GLF) (proposed ‘GLF model’), predicted by a new liver-perfusion-based dose-response model. The resulting \\ell \\text{EUD} , fEUD, and GLF plans delivering the same target \\ell \\text{EUD} are compared with respect to their post-treatment function and various dose-based metrics. Voxel-based portal venous liver perfusion, used as a measure of local function, is computed using DCE-MRI. In cases used in our experiments, the GLF plan preserves up to 4.6 % ≤ft(7.5 % \\right) more liver function than the fEUD (\\ell \\text{EUD} ) plan does in 2D cases, and up to 4.5 % ≤ft(5.6 % \\right) in 3D cases. The GLF and fEUD plans worsen in \\ell \\text{EUD} of functional liver on average by 1.0 Gy and 0.5 Gy in 2D and 3D cases, respectively. Liver perfusion information can be used during treatment planning to minimize the risk of toxicity by improving expected GLF; the degree of benefit varies with perfusion pattern. Although fEUD model optimization is computationally inexpensive and
4. A simple planning technique of craniospinal irradiation in the eclipse treatment planning system
Directory of Open Access Journals (Sweden)
Hemalatha Athiyaman
2014-01-01
Full Text Available A new planning method for Craniospinal Irradiation by Eclipse treatment planning system using Field alignment, Field-in-Field technique was developed. Advantage of this planning method was also studied retrospectively for previously treated five patients of medulloblastoma with variable spine length. Plan consists of half beam blocked parallel opposed cranium, and a single posterior cervicospine field was created by sharing the same isocenter, which obviates divergence matching. Further, a single symmetrical field was created to treat remaining Lumbosacral spine. Matching between a inferior diverging edge of cervicospine field and superior diverging edge of a Lumbosacral field was done using the field alignment option. ′Field alignment′ is specific option in the Eclipse Treatment Planning System, which automatically matches the field edge divergence as per field alignment rule. Multiple segments were applied in both the spine field to manage with hot and cold spots created by varying depth of spinal cord. Plan becomes fully computerized using this field alignment option and multiple segments. Plan evaluation and calculated mean modified Homogeneity Index (1.04 and 0.1 ensured that dose to target volume is homogeneous and critical organ doses were within tolerance. Dose variation at the spinal field junction was verified using ionization chamber array (I′MatriXX for matched, overlapped and gap junction spine fields; the delivered dose distribution confirmed the ideal clinical match, over exposure and under exposure at the junction, respectively. This method is simple to plan, executable in Record and Verify mode and can be adopted for various length of spinal cord with only two isocenter in shorter treatment time.
5. Conformal three dimensional radiotherapy treatment planning in Lund
Energy Technology Data Exchange (ETDEWEB)
Knoos, T.; Nilsson, P. [Lund Univ. (Sweden). Dept. of Radiation Physics; Anders, A. [Lund Univ. (Sweden). Dept. of Oncology
1995-12-01
The use of conformal therapy is based on 3-dimensional treatment planning as well as on methods and routines for 3-dimensional patient mapping, 3-dimensional virtual simulation and others. The management of patients at the Radiotherapy Department at the University Hospital in Lund (Sweden) is discussed. About 2100 new patients are annually treated with external radiotherapy using seven linear accelerators. Three of the accelerators have dual photon energies and electron treatment facilities. A multi-leaf collimator as well as an electronic portal imaging device are available on one machine. Two simulators and an in-house CT-scanner are used for treatment planning. From 1988 to 1992 Scandiplan (Umplan) was used. Since 1992, the treatment planning system is TMS (HELAX AB, Sweden), which is based on the pencil beam algorithm of Ahnesjo. The calculations use patient modulated accelerator specific energy fluence spectra which are compiled with pencil beams from Monte Carlo generated energy absorption kernels. Heterogeneity corrections are performed with results close to conventional algorithms. Irregular fields, either from standard or individual blocks and from multi-leaf collimators are handled by the treatment planning system. The field shape is determined conveniently using the beams eye view. The final field shape is exported electronically to either the block cutting machine or the multileaf collimator control computer. All patient fields are checked against the beams eye view during simulation using manual methods. Treatment verification is performed by portal films and in vivo dosimetry with silicon diodes or TL-dosimetry. Up to now, approximately 4400 patients have received a highly individualized 3-dimensional conformal treatment.
6. [Treatment of removable partial dentures. 1. Legislation, rules of conduct, care plan and treatment plan
NARCIS (Netherlands)
Witter, D.J.; Brands, W.G.; Barl, J.C.; Creugers, N.H.J.
2011-01-01
An invasive treatment, such as the treatment involving a removable partial denture, requires a well-structured approach. Regulations governing the communication between a healthcare professional and a patient in the Netherlands can be found in the Dutch Medical Treatment Act and the Rules of Conduct
7. Computer calculations in interstitial seed therapy: I. Radiation treatment planning
International Nuclear Information System (INIS)
Interstitial seed therapy computers can be used for radiation treatment planning and for dose control after implantation. In interstitial therapy with radioactive seeds there are much greater differences between planning and carrying out radiation treatment than in teletherapy with cobalt-60 or X-rays. Because of the short distance between radioactive sources and tumour tissue, even slight deviations from the planned implantation geometry cause considerable dose deviations. Furthermore, the distribution of seeds in an actual implant is inhomogeneous. During implantation the spatial distribution of seeds cannot be examined exactly, though X-rays are used to control the operation. The afterloading technique of Henschke allows a more exact implantation geometry, but I have no experience of this method. In spite of the technical difficulty of achieving optimum geometry, interstitial therapy still has certain advantages when compared with teletherapy: the dose in the treated volume can be kept smaller than in teletherapy, the radiation can be better concentrated in the tumour volume, the treatment can be restricted to one or two operations, and localized inoperable tumours may be cured more easily. The latter may depend on an optimal treatment time, a relatively high tumour dose and a continuous exponentially decreasing dose rate during the treatment time. A disadvantage of interstitial therapy is the high personnel dose, which may be reduced by the afterloading technique of Henschke (1956). However, the afterloading method requires much greater personnel and instrumental expense than free implantation of radiogold seeds and causes greater trauma for the patient
8. Dosimetric tests for treatment planning commissioning in 3DCRT
International Nuclear Information System (INIS)
The radiotherapy evolution from 2D treatments to 3D conformal treatments was possible after the advent the treatment planning systems commercially available and tridimensional images techniques like computed tomography. These systems have tools that allow delineate anatomical structures from tomographic images. Calculations dose tools allow the planner evaluate the dose received in the anatomical structures. When these systems are acquired or an upgrade is made many dosimetric and non-dosimetric tests need to be performed to know the system limitations and correct functioning and to verify the correct dosimetric data insertion. This study was based in International Atomic Energy Agency protocols, Task Groups documents from American Association of Physics in Medicine, and other papers. A dosimetric test set was done to commissioning the Eclipse 10.0.28 (Varian Medical Systems) treatments planning system This version has two photon calculation algorithm (Pencil Beam Convolution and Analytical Anisotropic Algorithm – AAA) and Gaussian Pencil Beam algorithm for electron beams. However, tests for AAA it was not performed. In this study was possible to conclude that the dosimetric data was correctly added in the treatment planning system. Some results allowed to understand the algorithm limitations to calculate dose distributions in specifics situations, that was not clinically relevant in our routine. (author)
9. Emergency assessment and treatment planning for traumatic dental injuries.
Science.gov (United States)
Moule, A; Cohenca, N
2016-03-01
Trauma involving the dentoalveolar region is a frequent occurrence which can result in the fracturing and displacement of teeth, crushing and/or fracturing of bone and soft tissue injuries including contusions, abrasions and lacerations. This review describes the assessment of patients with these injuries, not in a didactic sense by repeating excellent already published classifications and treatment options, but by addressing questions that arise during assessment. It covers trauma first aid, examination of the patient, factors that affect treatment planning decisions, and the importance of communicating treatment options and prognosis to traumatized patients. PMID:26923446
10. Neutron field characterization in the installation for BNCT study in the IEA-R1 reactor; Caracterizacao do campo de neutrons na instalacao para estudo em BNCT no reator IEA-R1
Energy Technology Data Exchange (ETDEWEB)
Carneiro Junior, Valdeci
2008-07-01
This work aims to characterize the mixed neutron and gamma field, in the sample irradiation position, in a research installation for Boron Neutron Capture Therapy (BNCT), in the IPEN IEA-R1 reactor. The BNCT technique has been studied as a safe and selective option in the treatment of resistant cancerigenous tumors or considered non-curable by the conventional techniques, for example, the Glioblastoma Multiform - a brain cancerigenous tumor. Neutron flux measurements were carried out: thermal, resonance and fast, as well as neutron and gamma rays doses, in the sample position, using activation foils detectors and thermoluminescent dosimeters. For the determination of the neutron spectrum and intensity, a set of different threshold activation foils and gold foils covered and uncovered with cadmium irradiated in the installation was used, analyzed by a high Pure Germanium semiconductor detector, coupled to an electronic system suitable for gamma spectrometry. The results were processed with the SAND-BP code. The doses due to gamma and neutron rays were determined using thermoluminescent dosimeters TLD 400 and TLD 700 sensitive to gamma and TLD 600, sensitive to neutrons. The TLDs were selected and used for obtaining the calibration curves - dosimeter answer versus dose - from each of the TLD three types, which were necessary to calculate the doses due to neutron and gamma, in the sample position. The radiation field, in the sample irradiation position, was characterized flux for thermal neutrons of 1.39.10{sup 8} {+-} 0,12.10{sup 8} n/cm{sup 2}s the doses due to thermal neutrons are three times higher than those due to gamma radiation and confirm the reproducibility and consistency of the experimental findings obtained. Considering these results, the neutron field and gamma radiation showed to be appropriated for research in BNCT. (author)
11. A 4D treatment planning tool for the evaluation of motion effects on lung cancer treatments
International Nuclear Information System (INIS)
In this study, a 4D treatment planning tool using an analytical model accounting for breathing motion is investigated to evaluate the motion effect on delivered dose for lung cancer treatments with three-dimensional conformal radiotherapy (3DCRT). The Monte Carlo EGS4/MCDOSE user code is used in the treatment planning dose calculation, and the patient CT data are converted into respective patient geometry files for Monte Carlo dose calculation. The model interpolates CT images at different phases of the breathing cycle from patient CT scans taken at end inspiration and end expiration phases and the chest wall position. Correlation between the voxels in a reference CT dataset and the voxels in the interpolated CT datasets at any breathing phases is established so that the dose to a voxel can be accumulated through the entire breathing cycle. Simulated lung tumors at different locations are used to demonstrate our model in 3DCRT for lung cancer treatments. We demonstrated the use of a 4D treatment planning tool in evaluating the breathing motion effect on delivered dose for different planning margins. Further studies are being conducted to use this tool to study the lung motion effect through large-scale analysis and to implement this useful tool for treatment planning dose calculation and plan evaluation for 4D radiotherapy
12. Modeling treatment couches in the Pinnacle treatment planning system: Especially important for arc therapy.
Science.gov (United States)
Duggar, William Neil; Nguyen, Alex; Stanford, Jason; Morris, Bart; Yang, Claus C
2016-01-01
This study is to demonstrate the importance and a method of properly modeling the treatment couch for dose calculation in patient treatment using arc therapy. The 2 treatment couch tops-Aktina AK550 and Elekta iBEAM evo-of Elekta LINACs were scanned using Philips Brilliance Big Bore CT Simulator. Various parts of the couch tops were contoured, and their densities were measured and recorded on the Pinnacle treatment planning system (TPS) using the established computed tomography density table. These contours were saved as organ models to be placed beneath the patient during planning. Relative attenuation measurements were performed following procedures outlined by TG-176 as well as absolute dose comparison of static fields of 10 × 10 cm(2) that were delivered through the couch tops with that calculated in the TPS with the couch models. A total of 10 random arc therapy treatment plans (5 volumetric-modulated arc therapy [VMAT] and 5 stereotactic body radiation therapy [SBRT]), using 24 beams, were selected for this study. All selected plans were calculated with and without couch modeling. Each beam was evaluated using the Delta(4) dosimetry system (Delta(4)). The Student t-test was used to determine statistical significance. Independent reviews were exploited as per the Imaging and Radiation Oncology Core head and neck credentialing phantom. The selected plans were calculated on the actual patient anatomies with and without couch modeling to determine potential clinical effects. Large relative beam attenuations were noted dependent on which part of the couch top beams were passing through. Substantial improvements were also noted for static fields both calculated with the TPS and delivered physically when the couch models were included in the calculation. A statistically significant increase in agreement was noted for dose difference, distance to agreement, and γ-analysis with the Delta(4) on VMAT and SBRT plans. A credentialing review showed improvement in
13. Cell death following BNCT: a theoretical approach based on Monte Carlo simulations.
Science.gov (United States)
Ballarini, F; Bakeine, J; Bortolussi, S; Bruschi, P; Cansolino, L; Clerici, A M; Ferrari, C; Protti, N; Stella, S; Zonta, A; Zonta, C; Altieri, S
2011-12-01
In parallel to boron measurements and animal studies, investigations on radiation-induced cell death are also in progress in Pavia, with the aim of better characterisation of the effects of a BNCT treatment down to the cellular level. Such studies are being carried out not only experimentally but also theoretically, based on a mechanistic model and a Monte Carlo code. Such model assumes that: (1) only clustered DNA strand breaks can lead to chromosome aberrations; (2) only chromosome fragments within a certain threshold distance can undergo misrejoining; (3) the so-called "lethal aberrations" (dicentrics, rings and large deletions) lead to cell death. After applying the model to normal cells exposed to monochromatic fields of different radiation types, the irradiation section of the code was purposely extended to mimic the cell exposure to a mixed radiation field produced by the (10)B(n,α) (7)Li reaction, which gives rise to alpha particles and Li ions of short range and high biological effectiveness, and by the (14)N(n,p)(14)C reaction, which produces 0.58 MeV protons. Very good agreement between model predictions and literature data was found for human and animal cells exposed to X- or gamma-rays, protons and alpha particles, thus allowing to validate the model for cell death induced by monochromatic radiation fields. The model predictions showed good agreement also with experimental data obtained by our group exposing DHD cells to thermal neutrons in the TRIGA Mark II reactor of the University of Pavia; this allowed to validate the model also for a BNCT exposure scenario, providing a useful predictive tool to bridge the gap between irradiation and cell death. PMID:21481595
14. Approved Site Treatment Plan, Volumes 1 and 2. Revision 4
Energy Technology Data Exchange (ETDEWEB)
Helmich, E.H.; Molen, G.; Noller, D.
1996-03-22
The US Department of Energy, Savannah River Operations Office (DOE-SR), has prepared the Site Treatment Plan (STP) for Savannah River Site (SRS) mixed wastes in accordance with RCRA Section 3021(b), and SCDHEC has approved the STP (except for certain offsite wastes) and issued an order enforcing the STP commitments in Volume 1. DOE-SR and SCDHEC agree that this STP fulfills the requirements contained in the FFCAct, RCRA Section 3021, and therefore, pursuant to Section 105(a) of the FFCAct (RCRA Section 3021(b)(5)), DOEs requirements are to implement the plan for the development of treatment capacities and technologies pursuant to RCRA Section 3021. Emerging and new technologies not yet considered may be identified to manage waste more safely, effectively, and at lower cost than technologies currently identified in the plan. DOE will continue to evaluate and develop technologies that offer potential advantages in public acceptance, privatization, consolidation, risk abatement, performance, and life-cycle cost. Should technologies that offer such advantages be identified, DOE may request a revision/modification of the STP in accordance with the provisions of Consent Order 95-22-HW. The Compliance Plan Volume (Volume 1) identifies project activity schedule milestones for achieving compliance with Land Disposal Restrictions (LDR). Information regarding the technical evaluation of treatment options for SRS mixed wastes is contained in the Background Volume (Volume 2) and is provided for information.
15. Savannah River Site Approved Site Treatment Plan, 1998 Annual Update
Energy Technology Data Exchange (ETDEWEB)
Lawrence, B. [Westinghouse Savannah River Company, AIKEN, SC (United States); Berry, M.
1998-03-01
The U.S. Department of Energy, Savannah River Operations Office (DOE- SR),has prepared the Site Treatment Plan (STP) for Savannah River Site (SRS) mixed wastes in accordance with RCRA Section 3021(b), and SCDHEC has approved the STP (except for certain offsite wastes) and issued an order enforcing the STP commitments in Volume I. DOE-SR and SCDHEC agree that this STP fulfills the requirements contained in the FFCAct, RCRA Section 3021, and therefore,pursuant to Section 105(a) of the FFCAct (RCRA Section 3021(b)(5)), DOEs requirements are to implement the plan for the development of treatment capacities and technologies pursuant to RCRA Section 3021.Emerging and new technologies not yet considered may be identified to manage waste more safely, effectively, and at lower cost than technologies currently identified in the plan. DOE will continue to evaluate and develop technologies that offer potential advantages in public acceptance, privatization, consolidation, risk abatement, performance, and life-cycle cost. Should technologies that offer such advantages be identified, DOE may request a revision/modification of the STP in accordance with the provisions of Consent Order 95-22-HW.The Compliance Plan Volume (Volume I) identifies project activity schedule milestones for achieving compliance with Land Disposal Restrictions (LDR). Information regarding the technical evaluation of treatment options for SRS mixed wastes is contained in the Background Volume (Volume II) and is provided for information.
16. Approved Site Treatment Plan, Volumes 1 and 2. Revision 4
International Nuclear Information System (INIS)
The US Department of Energy, Savannah River Operations Office (DOE-SR), has prepared the Site Treatment Plan (STP) for Savannah River Site (SRS) mixed wastes in accordance with RCRA Section 3021(b), and SCDHEC has approved the STP (except for certain offsite wastes) and issued an order enforcing the STP commitments in Volume 1. DOE-SR and SCDHEC agree that this STP fulfills the requirements contained in the FFCAct, RCRA Section 3021, and therefore, pursuant to Section 105(a) of the FFCAct (RCRA Section 3021(b)(5)), DOE's requirements are to implement the plan for the development of treatment capacities and technologies pursuant to RCRA Section 3021. Emerging and new technologies not yet considered may be identified to manage waste more safely, effectively, and at lower cost than technologies currently identified in the plan. DOE will continue to evaluate and develop technologies that offer potential advantages in public acceptance, privatization, consolidation, risk abatement, performance, and life-cycle cost. Should technologies that offer such advantages be identified, DOE may request a revision/modification of the STP in accordance with the provisions of Consent Order 95-22-HW. The Compliance Plan Volume (Volume 1) identifies project activity schedule milestones for achieving compliance with Land Disposal Restrictions (LDR). Information regarding the technical evaluation of treatment options for SRS mixed wastes is contained in the Background Volume (Volume 2) and is provided for information
17. Monte Carlo conformal treatment planning as an independent assessment
Energy Technology Data Exchange (ETDEWEB)
Rincon, M.; Leal, A.; Perucha, M.; Carrasco, E. [Sevilla Univ. (Spain). Dept. Fisiologia Medica y Biofisica; Sanchez-Doblado, F. [Sevilla Univ. (Spain). Dept. Fisiologia Medica y Biofisica]|[Hospital Univ. Virgen Macarena, Sevilla (Spain). Servicio de Oncologia Radioterapica; Arrans, R.; Sanchez-Calzado, J.A.; Errazquin, L. [Hospital Univ. Virgen Macarena, Sevilla (Spain). Servicio de Oncologia Radioterapica; Medrano, J.C. [Clinica Puerta de Hierro, Madrid (Spain). Servicio de Radiofisica
2001-07-01
The wide range of possibilities available in Radiotherapy with conformal fields cannot be covered experimentally. For this reason, dosimetrical and planning procedures are based on approximate algorithms or systematic measurements. Dose distribution calculations based on Monte Carlo (MC) simulations can be used to check results. In this work, two examples of conformal field treatments are shown: A prostate carcinoma and an ocular lymphoma. The dose distributions obtained with a conventional Planning System and with MC have been compared. Some significant differences have been found. (orig.)
18. Continuity of Care: Sharing the Medication Treatment Plan.
Science.gov (United States)
Spahni, Stéphane
2016-01-01
The shared medication treatment plan is a key element for supporting the continuity of care. Indeed a substantial amount of emergency hospitalization is linked to medication - 5% to 10% according to some studies. Methods and tools helping all healthcare providers to have a better knowledge of the complete medication plan are therefore required in order to limit side effects linked to an insufficient knowledge of what the patient is taking. The workshop intends to present various initiatives and open the discussion about the limits, pros and cons of various initiatives. PMID:27332315
19. Monte Carlo conformal treatment planning as an independent assessment
International Nuclear Information System (INIS)
The wide range of possibilities available in Radiotherapy with conformal fields cannot be covered experimentally. For this reason, dosimetrical and planning procedures are based on approximate algorithms or systematic measurements. Dose distribution calculations based on Monte Carlo (MC) simulations can be used to check results. In this work, two examples of conformal field treatments are shown: A prostate carcinoma and an ocular lymphoma. The dose distributions obtained with a conventional Planning System and with MC have been compared. Some significant differences have been found. (orig.)
20. Spectrum shaping of accelerator-based neutron beams for BNCT
CERN Document Server
Montagnini, B; Esposito, J; Giusti, V; Mattioda, F; Varone, R
2002-01-01
We describe Monte Carlo simulations of three facilities for the production of epithermal neutrons for Boron Neutron Capture Therapy (BNCT) and examine general aspects and problems of designing the spectrum-shaping assemblies to be used with these neutron sources. The first facility is based on an accelerator-driven low-power subcritical reactor, operating as a neutron amplifier. The other two facilities have no amplifier and rely entirely on their primary sources, a D-T fusion reaction device and a conventional 2.5 MeV proton accelerator with a Li target, respectively.
1. Orthodontic treatment plan changed by 3D images
International Nuclear Information System (INIS)
Clinical application of CBCT is most often enforced in dental phenomenon of impacted teeth, hyperodontia, transposition, ankyloses or root resorption and other pathologies in the maxillofacial area. The goal, we put ourselves, is to show how the information from 3D images changes the protocol of the orthodontic treatment. The material, we presented six our clinical cases and the change in the plan of the treatment, which has used after analyzing the information carried on the three planes of CBCT. These cases are casuistic in the orthodontic practice and require individual approach to each of them during their analysis and decision taken. The discussion made by us is in line with reveal of the impacted teeth, where we need to evaluate their vertical depth and mediodistal ratios with the bond structures. At patients with hyperodontia, the assessment is of outmost importance to decide which of the teeth to be extracted and which one to be arranged into the dental arch. The conclusion we make is that diagnostic information is essential for decisions about treatment plan. The exact graphs will lead to better treatment plan and more predictable results. (authors) Key words: CBCT. IMPACTED CANINES. HYPERODONTIA. TRANSPOSITION
2. Generalized Tumor Dose for Treatment Planning Decision Support
Science.gov (United States)
Zuniga, Areli A.
Modern radiation therapy techniques allow for improved target conformity and normal tissue sparing. These highly conformal treatment plans have allowed dose escalation techniques increasing the probability of tumor control. At the same time this conformation has introduced inhomogeneous dose distributions, making delivered dose characterizations more difficult. The concept of equivalent uniform dose (EUD) characterizes a heterogeneous dose distribution within irradiated structures as a single value and has been used in biologically based treatment planning (BBTP); however, there are no substantial validation studies on clinical outcome data supporting EUD's use and therefore has not been widely adopted as decision-making support. These highly conformal treatment plans have also introduced the need for safety margins around the target volume. These margins are designed to minimize geometrical misses, and to compensate for dosimetric and treatment delivery uncertainties. The margin's purpose is to reduce the chance of tumor recurrence. This dissertation introduces a new EUD formulation designed especially for tumor volumes, called generalized Tumor Dose (gTD). It also investigates, as a second objective, margins extensions for potential improvements in local control while maintaining or minimizing toxicity. The suitability of gTD to rank LC was assessed by means of retrospective studies in a head and neck (HN) squamous cell carcinoma (SCC) and non-small cell lung cancer (NSCLC) cohorts. The formulation was optimized based on two datasets (one of each type) and then, model validation was assessed on independent cohorts. The second objective of this dissertation was investigated by ranking the probability of LC of the primary disease adding different margin sizes. In order to do so, an already published EUD formula was used retrospectively in a HN and a NSCLC datasets. Finally, recommendations for the viability to implement this new formulation into a routine treatment
3. Speed optimized influence matrix processing in inverse treatment planning tools
Energy Technology Data Exchange (ETDEWEB)
Ziegenhein, Peter; Wilkens, Jan J; Nill, Simeon; Oelfke, Uwe [German Cancer Research Center (DKFZ), Department of Medical Physics in Radiation Oncology, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Ludwig, Thomas [University of Heidelberg, Institute of Computer Science, Research Group Parallel and Distributed Systems, Im Neuenheimer Feld 348, 69120 Heidelberg (Germany)], E-mail: [email protected], E-mail: [email protected]
2008-05-07
An optimal plan in modern treatment planning tools is found through the use of an iterative optimization algorithm, which deals with a high amount of patient-related data and number of treatment parameters to be optimized. Thus, calculating a good plan is a very time-consuming process which limits the application for patients in clinics and for research activities aiming for more accuracy. A common technique to handle the vast amount of radiation dose data is the concept of the influence matrix (DIJ), which stores the dose contribution of each bixel to the patient in the main memory of the computer. This study revealed that a bottleneck for the optimization time arises from the data transfer of the dose data between the memory and the CPU. In this note, we introduce a new method which speeds up the data transportation from stored dose data to the CPU. As an example we used the DIJ approach as is implemented in our treatment planning tool KonRad, developed at the German Cancer Research Center (DKFZ) in Heidelberg. A data cycle reordering method is proposed to take the advantage of modern memory hardware. This induces a minimal eviction policy which results in a memory behaviour exhibiting a 2.6 times faster algorithm compared to the naive implementation. Although our method is described for the DIJ approach implemented in KonRad, we believe that any other planning tool which uses a similar approach to store the dose data will also benefit from the described methods. (note)
4. Treatment planning in radiosurgery: parallel Monte Carlo simulation software
Energy Technology Data Exchange (ETDEWEB)
Scielzo, G. [Galliera Hospitals, Genova (Italy). Dept. of Hospital Physics; Grillo Ruggieri, F. [Galliera Hospitals, Genova (Italy) Dept. for Radiation Therapy; Modesti, M.; Felici, R. [Electronic Data System, Rome (Italy); Surridge, M. [University of South Hampton (United Kingdom). Parallel Apllication Centre
1995-12-01
The main objective of this research was to evaluate the possibility of direct Monte Carlo simulation for accurate dosimetry with short computation time. We made us of: graphics workstation, linear accelerator, water, PMMA and anthropomorphic phantoms, for validation purposes; ionometric, film and thermo-luminescent techniques, for dosimetry; treatment planning system for comparison. Benchmarking results suggest that short computing times can be obtained with use of the parallel version of EGS4 that was developed. Parallelism was obtained assigning simulation incident photons to separate processors, and the development of a parallel random number generator was necessary. Validation consisted in: phantom irradiation, comparison of predicted and measured values good agreement in PDD and dose profiles. Experiments on anthropomorphic phantoms (with inhomogeneities) were carried out, and these values are being compared with results obtained with the conventional treatment planning system.
5. Backgrounds of computer-assisted treatment planning in radiation therapy
International Nuclear Information System (INIS)
Interaction of ionising radiation and living materials causes biological damage of tempory or permanent nature. In radiation therapy this phenomenon is used in a controlled fashion in order to stop the proliferation of malignant cells, while at the same time limiting the permanent damage to healthy tissues and organs to at least tolerable levels. Because of the often relatively small differences in response of malignant growths and normal tissues, the margins between tolerable and intolerable are so small that the greatest precision in treatment planning and execution is required. The nature of this treatment agent implies that the radiation therapist has to rely very much on instrumentally obtained and processed information, in all phases of this medical activities around the patient. In this paper a description is given of the backgrounds of computer-assisted methods which have enabled modern individualised and optimised planning for therapy with high energy X- and gamma beams. (orig.)
6. Radiation-induced meningiomas after BNCT in patients with malignant glioma.
Science.gov (United States)
Kageji, T; Sogabe, S; Mizobichi, Y; Nakajima, K; Shinji, N; Nakagawa, Y
2015-12-01
Of the 180 patients with malignant brain tumors whom we treated with boron neutron capture therapy (BNCT) since 1968, only one (0.56%) developed multiple radiation-induced meningiomas. The parasagittal meningioma that had received 42 Gy (w) for BNCT showed more rapid growth on Gd-enhanced MRI scans and more atypical features on histopathologic studies than the temporal convexity tumor that had received 20 Gy (w). Long-term follow up MRI studies are necessary in long-survivors of malignant brain tumors treated by BNCT. PMID:26122975
7. Correlation of clinical outcome to the estimated radiation dose from Boron Neutron Capture Therapy (BNCT)
Energy Technology Data Exchange (ETDEWEB)
Chadha, M. [Beth Israel Medical Center, NY (United States). Dept. of Radiation Oncology; Coderre, J.A.; Chanana, A.D. [Brookhaven National Lab., Upton, NY (United States)] [and others
1996-12-31
A phase I/II trial delivering a single fraction of BNCT using p-Boronophenylalanine-Fructose and epithermal neutrons at the the Brookhaven Medical Research Reactor was initiated in September 1994. The primary endpiont of the study was to evaluate the feasibility and safety of a given BNCT dose. The clinical outcome of the disease was a secondary endpoint of the study. The objective of this paper is to evaluate the correlation of the clinical outcome of patients to the estimated radiation dose from BNCT.
8. Generating Treatment Plan in Medicine: A Data Mining Approach
Directory of Open Access Journals (Sweden)
2009-01-01
Full Text Available This study reports on a research effort on generating treatment plan to handle the error and complexity of treatment process for healthcare providers. Focus has been given for outpatient and was based on data collected from various health centers throughout Malaysia. These clinical data were recorded using SOAP (Subjective, Objective, Assessment and Plan format approach as being practiced in medicine and were recorded electronically via Percuro Clinical Information System (Percuro. Cross-Industry Standard Process for Data Mining (CRISP-DM model has been utilized for the entire research. We used data mining analysis through decision trees technique with C5 algorithm. The scopes that have been set are patients complaint, gender, age, race, type of plan and detailed item given to patient. Acute upper respiratory infection disease or identified as J06.9 in International Classification of Diseases 10 by World Health Organization has been selected as it was the most common problem encountered. The model created for J06.9 disease is that type of plan recommended through giving drug to patients without the need to consider patients complaint, gender, age and race, with accuracy obtained for the model is 94.73%. Inspite of that, we also identified detailed items that have been given to J06.9 patients and the occurancy of them. This can be as a guideline for future treatment with item recommendation is less than 0.078% compared to item inventory in Percuro database. The research is expected to aid healthcare provider as well as to minimize error during treatment process while benefited from technology information to increase the health care delivery.
9. Patients with hip prosthesis: radiotherapy treatment planning considerations
International Nuclear Information System (INIS)
The number of patients with hip prosthesis undergoing radiotherapy for pelvic cancer worldwide is increasing. This might be of importance depending on the materials in the prosthesis and whether any of the treatment fields are involved in the prosthesis. Radiotherapy planning involving the pelvic region of patients having total hip prosthesis has been found to be difficult due to the effect of the prosthesis on the dose distribution. This review is intended to project dosimetric considerations and possible solutions to this uncommon problem
10. Dosimetric verification of a commercial inverse treatment planning system
Science.gov (United States)
Xing, Lei; Curran, Bruce; Hill, Robert; Holmes, Tim; Ma, Lijun; Forster, Kenneth M.; Boyer, Arthur L.
1999-02-01
A commercial three-dimensional (3D) inverse treatment planning system, Corvusimages/0031-9155/44/2/013/img10.gif" ALIGN="TOP"/> (Nomos Corporation, Sewickley, PA), was recently made available. This paper reports our preliminary results and experience with commissioning this system for clinical implementation. This system uses a simulated annealing inverse planning algorithm to calculate intensity-modulated fields. The intensity-modulated fields are divided into beam profiles that can be delivered by means of a sequence of leaf settings by a multileaf collimator (MLC). The treatments are delivered using a computer-controlled MLC. To test the dose calculation algorithm used by the Corvus software, the dose distributions for single rectangularly shaped fields were compared with water phantom scan data. The dose distributions predicted to be delivered by multiple fields were measured using an ion chamber that could be positioned in a rotatable cylindrical water phantom. Integrated charge collected by the ion chamber was used to check the absolute dose of single- and multifield intensity modulated treatments at various spatial points. The measured and predicted doses were found to agree to within 4% at all measurement points. Another set of measurements used a cubic polystyrene phantom with radiographic film to record the radiation dose distribution. The films were calibrated and scanned to yield two-dimensional isodose distributions. Finally, a beam imaging system (BIS) was used to measure the intensity-modulated x-ray beam patterns in the beam's-eye view. The BIS-measured images were then compared with a theoretical calculation based on the MLC leaf sequence files to verify that the treatment would be executed accurately and without machine faults. Excellent correlation (correlation coefficients images/0031-9155/44/2/013/img11.gif" ALIGN="TOP"/>) was found for all cases. Treatment plans generated using intensity-modulated beams appear to be suitable for treatment of
11. Monte Carlo treatment planning for photon and electron beams
Science.gov (United States)
Reynaert, N.; van der Marck, S. C.; Schaart, D. R.; Van der Zee, W.; Van Vliet-Vroegindeweij, C.; Tomsej, M.; Jansen, J.; Heijmen, B.; Coghe, M.; De Wagter, C.
2007-04-01
During the last few decades, accuracy in photon and electron radiotherapy has increased substantially. This is partly due to enhanced linear accelerator technology, providing more flexibility in field definition (e.g. the usage of computer-controlled dynamic multileaf collimators), which led to intensity modulated radiotherapy (IMRT). Important improvements have also been made in the treatment planning process, more specifically in the dose calculations. Originally, dose calculations relied heavily on analytic, semi-analytic and empirical algorithms. The more accurate convolution/superposition codes use pre-calculated Monte Carlo dose "kernels" partly accounting for tissue density heterogeneities. It is generally recognized that the Monte Carlo method is able to increase accuracy even further. Since the second half of the 1990s, several Monte Carlo dose engines for radiotherapy treatment planning have been introduced. To enable the use of a Monte Carlo treatment planning (MCTP) dose engine in clinical circumstances, approximations have been introduced to limit the calculation time. In this paper, the literature on MCTP is reviewed, focussing on patient modeling, approximations in linear accelerator modeling and variance reduction techniques. An overview of published comparisons between MC dose engines and conventional dose calculations is provided for phantom studies and clinical examples, evaluating the added value of MCTP in the clinic. An overview of existing Monte Carlo dose engines and commercial MCTP systems is presented and some specific issues concerning the commissioning of a MCTP system are discussed.
12. In-house quality check of external beam plans using 3D treatment planning systems - a DVH comparison.
Science.gov (United States)
Kumar, Ayyalasomayajula Anil; Akula, Roopa Rani; Ayyangar, Komanduri; P, Krishna Reddy; Vuppu, Srinivas; Narayana, P V Lakshmi; Rao, A Durga Prasada
2016-01-01
This paper presents a new approach towards the quality assurance of external beam plans using in-house-developed DICOM import and export software in a clinical setup. The new approach is different from what is currently used in most clinics, viz., only MU and point dose are verified. The DICOM-RT software generates ASCII files to import/export structure sets, treatment beam data, and dose-volume histo-grams (DVH) from one treatment planning system (TPS) to the other. An efficient and reliable 3D planning system, ROPS, was used for verifying the accuracy of treatment plans and treatment plan parameters. With the use of this new approach, treatment plans planned using Varian Eclipse planning system were exported to ROPS planning system. Important treatment and dosimetrical data, such as the beam setup accuracy, target dose coverage, and dose to critical structures, were also quantitatively verified using DVH comparisons. Two external beam plans with diverse photon energies were selected to test the new approach. The satisfactory results show that the new approach is feasible, easy to use, and can be used as an adjunct test for patient treatment quality check. PMID:27167271
13. MO-C-BRF-01: Pediatric Treatment Planning I: Overview of Planning Strategies
Energy Technology Data Exchange (ETDEWEB)
Olch, A [Childrens Hospital of LA, Los Angeles, CA (United States); Hua, C [St. Jude Childrens Research Hospital, Memphis, TN (United States)
2014-06-15
Most Medical Physicists working in radiotherapy departments see few pediatric patients. This is because, fortunately, children get cancer at a rate nearly 100 times lower than adults. Children have not smoked, abused alcohol, or been exposed to environmental carcinogens for decades, and of course, have not fallen victim to the aging process. Children get very different cancers than adults. Breast or prostate cancers, typical in adults, are rarely seen in children but instead a variety of tumors occur in children that are rarely seen in adults; examples are germinomas, ependymomas and primitive neuroectodermal tumors, which require treatment of the child's brain or neuroblastoma, requiring treatment in the abdomen. The treatment of children with cancer using radiation therapy is one of the most challenging planning and delivery problems facing the physicist. This is because bones, brain, breast tissue, and other organs are more sensitive to radiation in children than in adults. Because most therapy departments treat mostly adults, when the rare 8 year-old patient comes to the department for treatment, the physicist may not understand the clinical issues of his disease which drive the planning and delivery decisions. Additionally, children are more prone than adults to developing secondary cancers after radiation. This fact has important implications for the choice of delivery techniques, especially when considering IMRT. For bilateral retinoblastoma for example, an irradiated child has a 50% chance of developing a second cancer by age 50. In the first presentation, an overview of childhood cancers and their corresponding treatment techniques will be given. These can be some of the most complex treatments that are delivered in the radiation therapy department. These cancers include leukemia treated with total body irradiation, medulloblastoma, treated with craniospinal irradiation plus a conformal boost to the posterior fossa, neuroblastoma, requiring focal
14. MO-C-BRF-01: Pediatric Treatment Planning I: Overview of Planning Strategies
International Nuclear Information System (INIS)
Most Medical Physicists working in radiotherapy departments see few pediatric patients. This is because, fortunately, children get cancer at a rate nearly 100 times lower than adults. Children have not smoked, abused alcohol, or been exposed to environmental carcinogens for decades, and of course, have not fallen victim to the aging process. Children get very different cancers than adults. Breast or prostate cancers, typical in adults, are rarely seen in children but instead a variety of tumors occur in children that are rarely seen in adults; examples are germinomas, ependymomas and primitive neuroectodermal tumors, which require treatment of the child's brain or neuroblastoma, requiring treatment in the abdomen. The treatment of children with cancer using radiation therapy is one of the most challenging planning and delivery problems facing the physicist. This is because bones, brain, breast tissue, and other organs are more sensitive to radiation in children than in adults. Because most therapy departments treat mostly adults, when the rare 8 year-old patient comes to the department for treatment, the physicist may not understand the clinical issues of his disease which drive the planning and delivery decisions. Additionally, children are more prone than adults to developing secondary cancers after radiation. This fact has important implications for the choice of delivery techniques, especially when considering IMRT. For bilateral retinoblastoma for example, an irradiated child has a 50% chance of developing a second cancer by age 50. In the first presentation, an overview of childhood cancers and their corresponding treatment techniques will be given. These can be some of the most complex treatments that are delivered in the radiation therapy department. These cancers include leukemia treated with total body irradiation, medulloblastoma, treated with craniospinal irradiation plus a conformal boost to the posterior fossa, neuroblastoma, requiring focal
15. Hemangiopericytoma - The need for a protocol-based treatment plan
Directory of Open Access Journals (Sweden)
Murugesan Krishnan
2011-01-01
Full Text Available Hemangiopericytoma is a vascular tumor which comprises only 1% of all vascular tumors. The frequency of occurrence in the head and neck accounts for about 16-33% of all hemangiopericytomas. In this paper we discuss the surgical management, the difficulties in decision-making and treatment-planning in a case of a maxillary tumor in a five-year-old boy with a two-year follow-up. A five-year-old boy presented with a large unilateral maxillary tumor with nasal obstruction. Computed tomography revealed a heterogeneous mass completely occupying the right maxillary sinus and displacing the lateral wall of the nose and nasal septum. The lesion was diagnosed as hemangiopericytoma after histopathological confirmation. The option of surgical resection (total maxillectomy was carried out after evaluating the available literature. Various treatment modalities like surgery, chemotherapy and radiotherapy were taken into consideration as the tumor has an aggressive nature. Due to the inadequate literature on definitive treatment options for these types of tumors, there was difficulty in arriving at a protocol-based treatment plan.
16. Investigating VMAT planning technique to reduce rectal and bladder dose in prostate cancer treatment plans
Directory of Open Access Journals (Sweden)
Suresh B Rana
2013-01-01
Full Text Available Background: RapidArc is a volumetric modulated arc therapy (VMAT technique that can deliver conformal dose distribution to the target while minimizing dose to critical structures. The main purpose of this study was to compare dosimetric quality of full double arc (full DA, full single arc (full SA, and partial double arc (partial DA techniques in RapidArc planning of prostate cancer. Materials and Methods: Twelve cases of prostate cancer involving seminal vesicles were selected for this retrospective study. For each case, RapidArc plans were created using full DA (two full arcs, full SA (one full arc, and partial DA (two partial arcs with anterior and posterior avoidance sectors techniques. For planning target volume (PTV, the maximum and mean doses, conformity, and inhomogeneity indices were evaluated. For bladder and rectum, volumes that received 70, 50, 40, and 20 Gy (V 70Gy , V 50Gy , V 40Gy and V 20Gy , respectively, and mean dose were compared. For femoral heads, V 40Gy , V 20Gy , and mean dose were evaluated. Additionally, an integral dose and monitor units (MUs were compared for each treatment plan. Results: In comparison to full DA and full SA techniques, the partial DA technique was better in sparing of rectum and bladder but delivered higher femoral head dose, which was nonetheless within the planning criteria. No clear dosimetric differences were found between full DA and partial DA plans for dose conformity and target homogeneity. The number of MUs and integral dose were largest with the partial DA technique and lowest with the full SA technique. Conclusion: The partial DA technique provides an alternative RapidArc planning approach for low risk prostate cancer.
17. Gene transfer-applied BNCT (g-BNCT) for amelanotic melanoma in brain. Further upregulation of 10B uptake by cell modulation
International Nuclear Information System (INIS)
Our success in eradicating melanoma by single BNCT with BPA led to the next urgent theme, i.e. application of such BNCT for currently uncurable melanoma metastasis in brain. In order to establish 10B-BPA-BNCT for melanoma in brain, we have investigated the pharmacokinetics of BPA which is most critical factor for successful BNCT, in melanotic and amelanotic and further tyrosinase gene-transfected amelanotic melanoma proliferating in brain having blood-brain-barrier, as compared to melanoma proliferating in skin. We have established three implanted models for melanoma in brain: 1) A1059 cells, amelanotic melanoma, 2) B16B15b cells, melanotic melanoma cells, highly metastatic to brain, and 3) TA1059 cells, with active melanogenesis induced by tyrosinase gene transfection. We would like to report the results of comparative analysis of the BPA uptake ability in these melanoma cells in both brain and skin. Based on these findings, we are further investigating to enhance 10B-BPA uptake by not only g-BNCT but also by additional melanogenesis upregulating cell modulation. (author)
18. Alpha-amino alcohol of para-boronophenylalanine, BPAol, as a potential boron carrier for BNCT
International Nuclear Information System (INIS)
α amino alcohol of boronophenylalanine BPAol in which -COOH group is replaced with hydrophilic group of -OH of p-boronophenylalanine (BPA) has been synthesized and its BNCT effect on experimental tumor models have been investigated. Tumor cell killing effect of BPAol on C6 gliosarcoma cells was very high 4.4 times as that of BPA, since it was actively accumulated into tumor cells in 4-5 times as that of BPA. Carboxylic group of BPA might not play as an essential role in uptake of BPA into tumor cells. BPAol-based BNCT strongly inhibited the tumor growth of Green's melanotic melanoma hamsters even under therapeutic dose of BPA-based BNCT. These preliminary findings strongly warrant further extensive pre-clinical study for BPAol as a boron carrier for BNCT. (author)
19. Artificial neural networks to evaluate the boron concentration decreasing profile in Blood-BPA samples of BNCT patients
Energy Technology Data Exchange (ETDEWEB)
Garcia-Reiriz, Alejandro, E-mail: [email protected] [Department of Analytical Chemistry, Faculty of Biochemical and Pharmaceutical Sciences, National University of Rosario, Rosario Institute of Chemistry (IQUIR-CONICET), Suipacha 531, Rosario S2002LRK (Argentina); Magallanes, Jorge [Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, San Martin, B1650KNA, Buenos Aires (Argentina); Zupan, Jure [National Institute of Chemistry, Hajdrihova 19, SLO-1000 Ljubljana, Eslovenia (Slovenia); Liberman, Sara [Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, San Martin, B1650KNA, Buenos Aires (Argentina)
2011-12-15
For the prediction of decay concentration profiles of the p-boronophenylalanine (BPA) in blood during BNCT treatment, a method is suggested based on Kohonen neural networks. The results of a model trained with the concentration profiles from the literature are described. The prediction of the model was validated by the leave-one-out method. Its robustness shows that it is mostly independent on small variations. The ability to fit retrospective experimental data shows an uncertainty lower than the two compartment model used previously. - Highlights: Black-Right-Pointing-Pointer We predicted decaying concentration profiles of BPA in blood during BNCT therapy. Black-Right-Pointing-Pointer Is suggested a method based on Kohonen neural networks. Black-Right-Pointing-Pointer The results show that it is very robust and mostly independent of small variations. Black-Right-Pointing-Pointer It has a better ability to fit retrospective experimental data. Black-Right-Pointing-Pointer The model could be progressively improved by adding new data to the training matrix.
20. SU-E-J-100: Reconstruction of Prompt Gamma Ray Three Dimensional SPECT Image From Boron Neutron Capture Therapy(BNCT)
Energy Technology Data Exchange (ETDEWEB)
Yoon, D; Jung, J; Suh, T [The Catholic University of Korea, College of medicine, Department of biomedical engineering (Korea, Republic of)
2014-06-01
Purpose: Purpose of paper is to confirm the feasibility of acquisition of three dimensional single photon emission computed tomography (SPECT) image from boron neutron capture therapy (BNCT) using Monte Carlo simulation. Methods: In case of simulation, the pixelated SPECT detector, collimator and phantom were simulated using Monte Carlo n particle extended (MCNPX) simulation tool. A thermal neutron source (<1 eV) was used to react with the boron uptake region (BUR) in the phantom. Each geometry had a spherical pattern, and three different BURs (A, B and C region, density: 2.08 g/cm3) were located in the middle of the brain phantom. The data from 128 projections for each sorting process were used to achieve image reconstruction. The ordered subset expectation maximization (OSEM) reconstruction algorithm was used to obtain a tomographic image with eight subsets and five iterations. The receiver operating characteristic (ROC) curve analysis was used to evaluate the geometric accuracy of reconstructed image. Results: The OSEM image was compared with the original phantom pattern image. The area under the curve (AUC) was calculated as the gross area under each ROC curve. The three calculated AUC values were 0.738 (A region), 0.623 (B region), and 0.817 (C region). The differences between length of centers of two boron regions and distance of maximum count points were 0.3 cm, 1.6 cm and 1.4 cm. Conclusion: The possibility of extracting a 3D BNCT SPECT image was confirmed using the Monte Carlo simulation and OSEM algorithm. The prospects for obtaining an actual BNCT SPECT image were estimated from the quality of the simulated image and the simulation conditions. When multiple tumor region should be treated using the BNCT, a reasonable model to determine how many useful images can be obtained from the SPECT could be provided to the BNCT facilities. This research was supported by the Leading Foreign Research Institute Recruitment Program through the National Research
1. SU-E-J-100: Reconstruction of Prompt Gamma Ray Three Dimensional SPECT Image From Boron Neutron Capture Therapy(BNCT)
International Nuclear Information System (INIS)
Purpose: Purpose of paper is to confirm the feasibility of acquisition of three dimensional single photon emission computed tomography (SPECT) image from boron neutron capture therapy (BNCT) using Monte Carlo simulation. Methods: In case of simulation, the pixelated SPECT detector, collimator and phantom were simulated using Monte Carlo n particle extended (MCNPX) simulation tool. A thermal neutron source (<1 eV) was used to react with the boron uptake region (BUR) in the phantom. Each geometry had a spherical pattern, and three different BURs (A, B and C region, density: 2.08 g/cm3) were located in the middle of the brain phantom. The data from 128 projections for each sorting process were used to achieve image reconstruction. The ordered subset expectation maximization (OSEM) reconstruction algorithm was used to obtain a tomographic image with eight subsets and five iterations. The receiver operating characteristic (ROC) curve analysis was used to evaluate the geometric accuracy of reconstructed image. Results: The OSEM image was compared with the original phantom pattern image. The area under the curve (AUC) was calculated as the gross area under each ROC curve. The three calculated AUC values were 0.738 (A region), 0.623 (B region), and 0.817 (C region). The differences between length of centers of two boron regions and distance of maximum count points were 0.3 cm, 1.6 cm and 1.4 cm. Conclusion: The possibility of extracting a 3D BNCT SPECT image was confirmed using the Monte Carlo simulation and OSEM algorithm. The prospects for obtaining an actual BNCT SPECT image were estimated from the quality of the simulated image and the simulation conditions. When multiple tumor region should be treated using the BNCT, a reasonable model to determine how many useful images can be obtained from the SPECT could be provided to the BNCT facilities. This research was supported by the Leading Foreign Research Institute Recruitment Program through the National Research
2. Oral diagnosis and treatment planning: part 5. Preventive and treatment planning for dental caries.
Science.gov (United States)
Yip, K; Smales, R
2012-09-01
The practice of operative dentistry continues to evolve, to reflect the many changes occurring in society and in dental diseases and conditions. However, the belief that all questionable and early carious lesions should be restored still persists. This belief is largely based upon the concept that the removal of all carious tissue followed by meticulous restoration of the tooth is the treatment of choice for dental caries. Yet restorations are not permanent and do not cure caries, as the causes remain. On the other hand, preventive measures can remove or partially remove the causes, thereby reducing the risks for future caries recurrence at the same site or elsewhere in the mouth.
3. IMRT treatment plans and functional planning with functional lung imaging from 4D-CT for thoracic cancer patients
International Nuclear Information System (INIS)
Currently, the inhomogeneity of the pulmonary function is not considered when treatment plans are generated in thoracic cancer radiotherapy. This study evaluates the dose of treatment plans on highly-functional volumes and performs functional treatment planning by incorporation of ventilation data from 4D-CT. Eleven patients were included in this retrospective study. Ventilation was calculated using 4D-CT. Two treatment plans were generated for each case, the first one without the incorporation of the ventilation and the second with it. The dose of the first plans was overlapped with the ventilation and analyzed. Highly-functional regions were avoided in the second treatment plans. For small targets in the first plans (PTV < 400 cc, 6 cases), all V5, V20 and the mean lung dose values for the highly-functional regions were lower than that of the total lung. For large targets, two out of five cases had higher V5 and V20 values for the highly-functional regions. All the second plans were within constraints. Radiation treatments affect functional lung more seriously in large tumor cases. With compromise of dose to other critical organs, functional treatment planning to reduce dose in highly-functional lung volumes can be achieved
4. Towards treatment planning and treatment of deep-seated solid tumors by electrochemotherapy
Directory of Open Access Journals (Sweden)
Bracko Matej
2010-02-01
Full Text Available Abstract Background Electrochemotherapy treats tumors by combining specific chemotherapeutic drugs with an intracellular target and electric pulses, which increases drug uptake into the tumor cells. Electrochemotherapy has been successfully used for treatment of easily accessible superficial tumor nodules. In this paper, we present the first case of deep-seated tumor electrochemotherapy based on numerical treatment planning. Methods The aim of our study was to treat a melanoma metastasis in the thigh of a patient. Treatment planning for electrode positioning and electrical pulse parameters was performed for two different electrode configurations: one with four and another with five long needle electrodes. During the procedure, the four electrode treatment plan was adopted and the patient was treated accordingly by electrochemotherapy with bleomycin. The response to treatment was clinically and radiographically evaluated. Due to a partial response of the treated tumor, the metastasis was surgically removed after 2 months and pathological analysis was performed. Results A partial response of the tumor to electrochemotherapy was obtained. Histologically, the metastasis showed partial necrosis due to electrochemotherapy, estimated to represent 40-50% of the tumor. Based on the data obtained, we re-evaluated the electrical treatment parameters in order to correlate the treatment plan with the clinical response. Electrode positions in the numerical model were updated according to the actual positions during treatment. We compared the maximum value of the measured electric current with the current predicted by the model and good agreement was obtained. Finally, tumor coverage with an electric field above the reversible threshold was recalculated and determined to be approximately 94%. Therefore, according to the calculations, a small volume of tumor cells remained viable after electrochemotherapy, and these were sufficient for tumor regrowth
5. Patient-specific dosimetric endpoints based treatment plan quality control in radiotherapy
Science.gov (United States)
Song, Ting; Staub, David; Chen, Mingli; Lu, Weiguo; Tian, Zhen; Jia, Xun; Li, Yongbao; Zhou, Linghong; Jiang, Steve B.; Gu, Xuejun
2015-11-01
In intensity modulated radiotherapy (IMRT), the optimal plan for each patient is specific due to unique patient anatomy. To achieve such a plan, patient-specific dosimetric goals reflecting each patient’s unique anatomy should be defined and adopted in the treatment planning procedure for plan quality control. This study is to develop such a personalized treatment plan quality control tool by predicting patient-specific dosimetric endpoints (DEs). The incorporation of patient specific DEs is realized by a multi-OAR geometry-dosimetry model, capable of predicting optimal DEs based on the individual patient’s geometry. The overall quality of a treatment plan is then judged with a numerical treatment plan quality indicator and characterized as optimal or suboptimal. Taking advantage of clinically available prostate volumetric modulated arc therapy (VMAT) treatment plans, we built and evaluated our proposed plan quality control tool. Using our developed tool, six of twenty evaluated plans were identified as sub-optimal plans. After plan re-optimization, these suboptimal plans achieved better OAR dose sparing without sacrificing the PTV coverage, and the dosimetric endpoints of the re-optimized plans agreed well with the model predicted values, which validate the predictability of the proposed tool. In conclusion, the developed tool is able to accurately predict optimally achievable DEs of multiple OARs, identify suboptimal plans, and guide plan optimization. It is a useful tool for achieving patient-specific treatment plan quality control.
6. Patient-specific dosimetric endpoints based treatment plan quality control in radiotherapy
International Nuclear Information System (INIS)
In intensity modulated radiotherapy (IMRT), the optimal plan for each patient is specific due to unique patient anatomy. To achieve such a plan, patient-specific dosimetric goals reflecting each patient’s unique anatomy should be defined and adopted in the treatment planning procedure for plan quality control. This study is to develop such a personalized treatment plan quality control tool by predicting patient-specific dosimetric endpoints (DEs). The incorporation of patient specific DEs is realized by a multi-OAR geometry-dosimetry model, capable of predicting optimal DEs based on the individual patient’s geometry. The overall quality of a treatment plan is then judged with a numerical treatment plan quality indicator and characterized as optimal or suboptimal. Taking advantage of clinically available prostate volumetric modulated arc therapy (VMAT) treatment plans, we built and evaluated our proposed plan quality control tool. Using our developed tool, six of twenty evaluated plans were identified as sub-optimal plans. After plan re-optimization, these suboptimal plans achieved better OAR dose sparing without sacrificing the PTV coverage, and the dosimetric endpoints of the re-optimized plans agreed well with the model predicted values, which validate the predictability of the proposed tool. In conclusion, the developed tool is able to accurately predict optimally achievable DEs of multiple OARs, identify suboptimal plans, and guide plan optimization. It is a useful tool for achieving patient-specific treatment plan quality control. (paper)
7. A novel implementation of mARC treatment for non-dedicated planning systems using converted IMRT plans
International Nuclear Information System (INIS)
The modulated arc (mARC) technique has recently been introduced by Siemens as an analogue to VMAT treatment. However, up to now only one certified treatment planning system supports mARC planning. We therefore present a conversion algorithm capable of converting IMRT plans created by any treatment planning system into mARC plans, with the hope of expanding the availability of mARC to a larger range of clinical users and researchers. As additional advantages, our implementation offers improved functionality for planning hybrid arcs and provides an equivalent step-and-shoot plan for each mARC plan, which can be used as a back-up concept in institutions where only one linac is equipped with mARC. We present a feasibility study to outline a practical implementation of mARC plan conversion using Philips Pinnacle and Prowess Panther. We present examples for three different kinds of prostate and head-and-neck plans, for 6 MV and flattening-filter-free (FFF) 7 MV photon energies, which are dosimetrically verified. It is generally more difficult to create good quality IMRT plans in Pinnacle using a large number of beams and few segments. We present different ways of optimization as examples. By careful choosing the beam and segment arrangement and inversion objectives, we achieve plan qualities similar to our usual IMRT plans. The conversion of the plans to mARC format yields functional plans, which can be irradiated without incidences. Absolute dosimetric verification of both the step-and-shoot and mARC plans by point dose measurements showed deviations below 5% local dose, mARC plans deviated from step-and-shoot plans by no more than 1%. The agreement between GafChromic film measurements of planar dose before and after mARC conversion is excellent. The comparison of the 3D dose distribution measured by PTW Octavius 729 2D-Array with the step-and-shoot plans and with the TPS is well above the pass criteria of 90% of the points falling within 5% local dose and 3 mm distance
8. Nevada Test Site Site Treatment Plan. Revision 2
International Nuclear Information System (INIS)
Treatment Plans (STPS) are required for facilities at which the US Department of Energy (DOE) or stores mixed waste, defined by the Federal Facility Compliance Act (FFCAct) as waste containing both a hazardous waste subject to the Resource Conservation and Recovery Act and a radioactive material subject to the Atomic Energy Act. On April 6, 1993, DOE published a Federal Register notice (58 FR 17875) describing its proposed process for developing the STPs in three phases including a Conceptual, a Draft, and a Proposed Site Treatment Plan (PSTP). All of the DOE Nevada Operations Office STP iterations have been developed with the state of Nevada's input. The options and schedules reflect a ''bottoms-up'' approach and have been evaluated for impacts on other DOE sites, as well as impacts to the overall DOE program. Changes may have occurred in the preferred option and associated schedules between the PSTP, which was submitted to the state of Nevada and US Environmental Protection Agency April 1995, and the Final STP (hereafter referred to as the STP) as treatment evaluations progressed. The STP includes changes that have occurred since the submittal of the PSTP as a result of state-to-state and DOE-to-state discussions
9. 3D volume visualization in remote radiation treatment planning
Science.gov (United States)
Yun, David Y.; Garcia, Hong-Mei C.; Mun, Seong K.; Rogers, James E.; Tohme, Walid G.; Carlson, Wayne E.; May, Stephen; Yagel, Roni
1996-03-01
This paper reports a novel applications of 3D visualization in an ARPA-funded remote radiation treatment planning (RTP) experiment, utilizing supercomputer 3D volumetric modeling power and NASA ACTS (Advanced Communication Technology Satellite) communication bandwidths at the Ka-band range. The objective of radiation treatment is to deliver a tumorcidal dose of radiation to a tumor volume while minimizing doses to surrounding normal tissues. High performance graphics computers are required to allow physicians to view a 3D anatomy, specify proposed radiation beams, and evaluate the dose distribution around the tumor. Supercomputing power is needed to compute and even optimize dose distribution according to pre-specified requirements. High speed communications offer possibilities for sharing scarce and expensive computing resources (e.g., hardware, software, personnel, etc.) as well as medical expertise for 3D treatment planning among hospitals. This paper provides initial technical insights into the feasibility of such resource sharing. The overall deployment of the RTP experiment, visualization procedures, and parallel volume rendering in support of remote interactive 3D volume visualization will be described.
10. A Monte Carlo dose calculation tool for radiotherapy treatment planning
Science.gov (United States)
Ma, C.-M.; Li, J. S.; Pawlicki, T.; Jiang, S. B.; Deng, J.; Lee, M. C.; Koumrian, T.; Luxton, M.; Brain, S.
2002-05-01
A Monte Carlo user code, MCDOSE, has been developed for radiotherapy treatment planning (RTP) dose calculations. MCDOSE is designed as a dose calculation module suitable for adaptation to host RTP systems. MCDOSE can be used for both conventional photon/electron beam calculation and intensity modulated radiotherapy (IMRT) treatment planning. MCDOSE uses a multiple-source model to reconstruct the treatment beam phase space. Based on Monte Carlo simulated or measured beam data acquired during commissioning, source-model parameters are adjusted through an automated procedure. Beam modifiers such as jaws, physical and dynamic wedges, compensators, blocks, electron cut-outs and bolus are simulated by MCDOSE together with a 3D rectilinear patient geometry model built from CT data. Dose distributions calculated using MCDOSE agreed well with those calculated by the EGS4/DOSXYZ code using different beam set-ups and beam modifiers. Heterogeneity correction factors for layered-lung or layered-bone phantoms as calculated by both codes were consistent with measured data to within 1%. The effect of energy cut-offs for particle transport was investigated. Variance reduction techniques were implemented in MCDOSE to achieve a speedup factor of 10-30 compared to DOSXYZ.
11. DVHs evaluation in brain metastases stereotactic radiotherapy treatment plans
International Nuclear Information System (INIS)
Purpose: The aim of this work is to report a retrospective study of radiobiological indicators based on Dose-Volume Histograms analysis obtained by stereotactic radiotherapy treatments. Methods and materials: Fifty-five patients for a total of sixty-seven brain metastases with a mean target volume of 8.49 cc were treated by Dynamic Conformal Arc Therapy (DCAT) and Intensity-Modulated Stereotactic Radiotherapy (IMRST). The Delivered prescription dose was chosen on the basis of tumor size and location so as to ensure a 100% isodose coverage to the target volume. Results: The treatment plans reported a mean value of 10% and 2.19% for the inhomogeneity and conformal index, respectively. The F factor showed we overdosed sixty-three patients delivering an additional 7% dose more than calculated values. The radiobiological parameters: TCP and NTCP showed a complete tumor control limiting the organs at risk damage. Conclusion: One goal of stereotactic radiotherapy is to design a treatment plan in which the steep dose gradient achievable minimizes the amount of radiation delivered outside the tumor region. This technique allows to deliver a much larger dose to the target without exceeding the radiation-related tolerance of normal tissues and improving patients' quality of life
12. Dose calculation and treatment planning for the Brookhaven NCT Facility
Energy Technology Data Exchange (ETDEWEB)
Liu, H.B.; Brugger, R.M.
1992-01-01
Consistency of the calculated to measured fluxes and doses in phantoms is important for confidence in treatment planning for Boron Neutron Capture Therapy at the Brookhaven Medical Research Reactor (BMRR). Two phantoms have been used to measure the thermal and epithermal flux and gamma dose distributions for irradiations at the BMRR and these are compared to MCNP calculations. Since MCNP calculations in phantoms or models would be lengthy if the calculations started each time with fission neutrons from the reactor core, a neutron source plane, which was verified by spectrum and flux measurements at the irradiation port, was designed. Measured doses in phantoms are especially important to verify the simulated neutron source plane. Good agreement between the calculated and measured values has been achieved and this neutron source plane is now used to predict flux and dose information for oncologists to form treatment plans as well as designing collimator and room shielding. In addition, a program using MCNP calculated results as input has been developed to predict reliable flux and dose distributions in the central coronal section of a head model for irradiation by the BMRR beam. Dosimetric comparisons and treatment examples are presented.
13. Dose calculation and treatment planning for the Brookhaven NCT Facility
Energy Technology Data Exchange (ETDEWEB)
Liu, H.B.; Brugger, R.M.
1992-12-31
Consistency of the calculated to measured fluxes and doses in phantoms is important for confidence in treatment planning for Boron Neutron Capture Therapy at the Brookhaven Medical Research Reactor (BMRR). Two phantoms have been used to measure the thermal and epithermal flux and gamma dose distributions for irradiations at the BMRR and these are compared to MCNP calculations. Since MCNP calculations in phantoms or models would be lengthy if the calculations started each time with fission neutrons from the reactor core, a neutron source plane, which was verified by spectrum and flux measurements at the irradiation port, was designed. Measured doses in phantoms are especially important to verify the simulated neutron source plane. Good agreement between the calculated and measured values has been achieved and this neutron source plane is now used to predict flux and dose information for oncologists to form treatment plans as well as designing collimator and room shielding. In addition, a program using MCNP calculated results as input has been developed to predict reliable flux and dose distributions in the central coronal section of a head model for irradiation by the BMRR beam. Dosimetric comparisons and treatment examples are presented.
14. 3-Dimentional radiotherapy versus conventional treatment plans for gastric cancer
Directory of Open Access Journals (Sweden)
Aghili M
2010-11-01
Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: The current standard of adjuvant management for gastric cancer after curative resection based on the results of intergroup 0116 is concurrent chemoradiation. Current guidelines for designing these challenging fields still include two-dimensional simulation with simple AP-PA parallel opposed design. However, the implementation of radiotherapy (RT remains a concern. Our objective was to compare three-dimensional (3D techniques to the more commonly used AP-PA technique."n"nMethods: A total of 24 patients with stages II-IV adenocarcinoma of the stomach were treated with adjuvant postoperative chemoradiation with simple AP-PA technique, using Cobalt-60. Total radiation dose was 50.4Gy. Landmark-based fields were simulated to assess PTV coverage. For each patient, three additional radiotherapy treatment plans were generated using three-dimensional (3D technique. The four treatment plans were then compared for target volume coverage and dose to normal tissues (liver, spinal cord, kidneys using dose volume histogram (DVH analysis."n"nResults: The three-dimensional planning techniques provided 10% superior PTV coverage compared to conventional AP-PA fields (p<0.001. Comparative DVHs for the right kidney, left kidney
15. Plutonium Finishing Plan (PFP) Treatment and Storage Unit Interim Status Closure Plan
International Nuclear Information System (INIS)
This document describes the planned activities and performance standards for closing the Plutonium Finishing Plant (PFP) Treatment and Storage Unit. The PFP Treatment and Storage Unit is located within the 234-52 Building in the 200 West Area of the Hanford Facility. Although this document is prepared based upon Title 40 Code of Federal Regulations (CFR), Part 265, Subpart G requirements, closure of the unit will comply with Washington Administrative Code (WAC) 173-303-610 regulations pursuant to Section 5.3 of the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Action Plan (Ecology et al. 1996). Because the PFP Treatment and Storage Unit manages transuranic mixed (TRUM) waste, there are many controls placed on management of the waste. Based on the many controls placed on management of TRUM waste, releases of TRUM waste are not anticipated to occur in the PFP Treatment and Storage Unit. Because the intention is to clean close the PFP Treatment and Storage Unit, postclosure activities are not applicable to this closure plan. To clean close the unit, it will be demonstrated that dangerous waste has not been left onsite at levels above the closure performance standard for removal and decontamination. If it is determined that clean closure is not possible or is environmentally impractical, the closure plan will be modified to address required postclosure activities. The PFP Treatment and Storage Unit will be operated to immobilize and/or repackage plutonium-bearing waste in a glovebox process. The waste to be processed is in a solid physical state (chunks and coarse powder) and will be sealed into and out of the glovebox in closed containers. The containers of immobilized waste will be stored in the glovebox and in additional permitted storage locations at PFP. The waste will be managed to minimize the potential for spills outside the glovebox, and to preclude spills from reaching soil. Containment surfaces will be maintained to ensure
16. Treatment planning for children with attention-deficit/hyperactivity disorder: treatment utilization and family preferences
Directory of Open Access Journals (Sweden)
William B Brinkman
2011-01-01
Full Text Available William B Brinkman, Jeffery N EpsteinDepartment of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USABackground: Attention-deficit/hyperactivity disorder (ADHD is a common condition that often results in child and family functional impairments. Although there are evidence-based treatment modalities available, implementation of and persistence with treatment plans vary with patients. Family preferences also vary and may contribute to variability in treatment utilization.Objective: The objective of this study is to describe the evidence-based treatments available for ADHD, identify patterns of use for each modality, and examine patient and parent treatment preferences.Method: Literature review.Results: Treatment options differ on benefits and risks/costs. Therefore, treatment decisions are preference sensitive and depend on how an informed patient/parent values the tradeoffs between options. Literature on patient and parent ADHD treatment preferences is based on quantitative research assessing the construct of treatment acceptability and qualitative and quantitative research that assesses preferences from a broader perspective. After a child is diagnosed with ADHD, a variety of factors influence the initial selection of treatment modalities that are utilized. Initial parent and child preferences are shaped by their beliefs about the nature of the child's problems and by information (and misinformation received from a variety of sources, including social networks, the media, and health care providers. Subsequently, preferences become further informed by personal experience with various treatment modalities. Over time, treatment plans are revisited and revised as families work with their health care team to establish a treatment plan that helps their child achieve goals while minimizing harms and costs.Conclusions: Studies have not been able to determine the extent to which
17. Conformal Radiotherapy: Physics, Treatment Planning and Verification. Proceedings book
Energy Technology Data Exchange (ETDEWEB)
De Wagter, C. [ed.
1995-12-01
The goal of conformal radiotherapy is to establish radiation dose distributions that conform tightly to the target volume in view of limiting radiation to normal tissues. Conformal radiotherapy significantly improves both local control and palliation and thus contributes to increase survival and to improve the quality of life. The subjects covered by the symposium include : (1) conformal radiotherapy and multi-leaf collimation; (2) three dimensional imaging; (3) treatment simulation, planning and optimization; (4) quality assurance; and (5) dosimetry. The book of proceedings contains the abstracts of the invited lectures, papers and poster presentations as well as the full papers of these contributions.
18. Computer assisted treatment planning for 125I ophthalmic plaque radiotherapy
International Nuclear Information System (INIS)
This paper describes a computer program for planning the treatment of ocular tumors with 125I plaques. The program permits the input of the tumor configuration into a model eye and facilitates the viewing of the relative geometry of the tumor and various eye structures in different perspectives. Custom-designed 125I plaques can be localized onto the globe, and dose distributions can be calculated and superimposed on the eye structures in any plane or on the inner eye surface. The program allows efficient evaluation of the plaque design in terms of radiation dose distribution relative to the tumor and critical structures
19. Conformal Radiotherapy: Physics, Treatment Planning and Verification. Proceedings book
International Nuclear Information System (INIS)
The goal of conformal radiotherapy is to establish radiation dose distributions that conform tightly to the target volume in view of limiting radiation to normal tissues. Conformal radiotherapy significantly improves both local control and palliation and thus contributes to increase survival and to improve the quality of life. The subjects covered by the symposium include : (1) conformal radiotherapy and multi-leaf collimation; (2) three dimensional imaging; (3) treatment simulation, planning and optimization; (4) quality assurance; and (5) dosimetry. The book of proceedings contains the abstracts of the invited lectures, papers and poster presentations as well as the full papers of these contributions
20. The BNCT facility at the HFR Petten: Quality assurance for reactor facilities in clinical trials
International Nuclear Information System (INIS)
The first clinical trial in Europe of Boron Neutron Capture Therapy (BNCT) for the treatment of glioblastoma was opened in July 1997. The trial is a Phase I study with the principal aim to establish the maximum tolerated radiation dose and the dose limiting toxicity under defined conditions. It is the first time that a clinical application could be realised on a completely multi-national scale. The treatment takes place at the High Flux Reactor (HFR) in Petten, the Netherlands, is operated by an international team of experts under the leadership of a German radiotherapist, and treats patients coming from different European countries. It has therefore been necessary to create a very specialised organisation and contractual structure with the support of administrations from different countries, who had to find and adapt solutions within existing laws that had never foreseen such a situation. Furthermore, the treatment does not take place in an hospital environment and even more so, the facility is at a nuclear research reactor. Hence, special efforts were made on quality assurance, in order that the set-up at the facility and the personnel involved complied, as closely as possible, with similar practices in conventional radiotherapy departments. (author)
1. Dose calculation accuracy of lung planning with a commercial IMRT treatment planning system.
Science.gov (United States)
McDermott, Patrick N; He, Tongming; DeYoung, A
2003-01-01
The dose calculation accuracy of a commercial pencil beam IMRT planning system is evaluated by comparison with Monte Carlo calculations and measurements in an anthropomorphic phantom. The target volume is in the right lung and mediastinum and thus significant tissue inhomogeneities are present. The Monte Carlo code is an adaptation of the MCNP code and the measurements were made with TLD and film. Both the Monte Carlo code and the measurements show very good agreement with the treatment planning system except in regions where the dose is high and the electron density is low. In these regions the commercial system shows doses up to 10% higher than Monte Carlo and film. The average calculated dose for the CTV is 5% higher with the commercial system as compared to Monte Carlo. PMID:14604424
2. Sampling and Analysis Plan Waste Treatment Plant Seismic Boreholes Project.
Energy Technology Data Exchange (ETDEWEB)
Brouns, Thomas M.
2007-07-15
This sampling and analysis plan (SAP) describes planned data collection activities for four entry boreholes through the sediment overlying the Saddle Mountains Basalt, up to three new deep rotary boreholes through the Saddle Mountains Basalt and sedimentary interbeds, and one corehole through the Saddle Mountains Basalt and sedimentary interbeds at the Waste Treatment Plant (WTP) site. The SAP will be used in concert with the quality assurance plan for the project to guide the procedure development and data collection activities needed to support borehole drilling, geophysical measurements, and sampling. This SAP identifies the American Society of Testing Materials standards, Hanford Site procedures, and other guidance to be followed for data collection activities. Revision 3 incorporates all interim change notices (ICN) that were issued to Revision 2 prior to completion of sampling and analysis activities for the WTP Seismic Boreholes Project. This revision also incorporates changes to the exact number of samples submitted for dynamic testing as directed by the U.S. Army Corps of Engineers. Revision 3 represents the final version of the SAP.
3. Antiproliferative effect and apoptosis induction in melanoma treatment by boron neutron capture therapy (BCNT)
Energy Technology Data Exchange (ETDEWEB)
Faiao-Flores, Fernanda; Coelho, Paulo; Arruda-Neto, Joao; Maria, Durvanei [University of Sao Paulo (USP), SP (Brazil)
2011-07-01
Full text: Introduction: Boron neutron capture therapy (BNCT) is an experimental radiotherapy where a compound having {sup 10}B is administered to cancer patients and is accumulated in tumor tissues. Thus, the tumor is irradiated with thermal neutrons, {sup 10}B absorbs and destroys them, producing alpha radiation. Boronophenylalanine (BPA) is the agent responsible for delivering boron to the tumor tissue. After BPA administration, BNCT is used as a localized radiotherapy for many tumors treatment, mainly melanoma, which has a high mortality rate among all types of tumors. The aim of this study was to evaluate in vitro antiproliferative and antitumor effects of BNCT application in human melanoma treatment. Materials and Methods: MEWO cells (human melanoma) were cultured and treated with different concentrations of BPA (8.36 to 0.52 mg/ml). After 90 minutes, they were irradiated with thermal neutron flux up to a dose of 8.4 Gy. The parameters analyzed were free radical production, cell cycle progression, cell death signaling pathways, cycling D1, caspase-3 and extracellular matrix synthesis produced, beyond the mitochondrial electric potential analysis. Results: After BNCT treatment, MEWO cells showed an amount of free radical increase about 10 times. Still, there was a significant decrease of cyclin D1, G0/G1 proliferation, synthesis and G2/M cell cycle phases. BNCT induced a mitochondrial electrical potential decrease, as well as fibrillar proteins of extracellular matrix. BNCT had a significant number of dead cell increase, mainly by necrosis. However, BNCT induced phosphorylated caspase 3 increase. Discussion/Conclusion: BNCT induced cell death increase by necrosis, mitochondrial electric potential decrease and free radical production increase. BNCT is cytotoxic to melanoma cells. Besides necrosis, phosphorylated caspase 3 increase was observed, accompanied by a proliferative response decrease regulated by the G1/S checkpoint and matrix extracellular synthesis
4. Integrated Waste Treatment Unit GFSI Risk Management Plan
International Nuclear Information System (INIS)
This GFSI Risk Management Plan (RMP) describes the strategy for assessing and managing project risks for the Integrated Waste Treatment Unit (IWTU) that are specifically within the control and purview of the U.S. Department of Energy (DOE), and identifies the risks that formed the basis for the DOE contingency included in the performance baseline. DOE-held contingency is required to cover cost and schedule impacts of DOE activities. Prior to approval of the performance baseline (Critical Decision-2) project cost contingency was evaluated during a joint meeting of the Contractor Management Team and the Integrated Project Team for both contractor and DOE risks to schedule and cost. At that time, the contractor cost and schedule risk value was $41.3M and the DOE cost and schedule risk contingency value is$39.0M. The contractor cost and schedule risk value of $41.3M was retained in the performance baseline as the contractor's management reserve for risk contingency. The DOE cost and schedule risk value of$39.0M has been retained in the performance baseline as the DOE Contingency. The performance baseline for the project was approved in December 2006 (Garman 2006). The project will continue to manage to the performance baseline and change control thresholds identified in PLN-1963, ''Idaho Cleanup Project Sodium-Bearing Waste Treatment Project Execution Plan'' (PEP)
5. Integrated Waste Treatment Unit GFSI Risk Management Plan
Energy Technology Data Exchange (ETDEWEB)
W. A. Owca
2007-06-21
This GFSI Risk Management Plan (RMP) describes the strategy for assessing and managing project risks for the Integrated Waste Treatment Unit (IWTU) that are specifically within the control and purview of the U.S. Department of Energy (DOE), and identifies the risks that formed the basis for the DOE contingency included in the performance baseline. DOE-held contingency is required to cover cost and schedule impacts of DOE activities. Prior to approval of the performance baseline (Critical Decision-2) project cost contingency was evaluated during a joint meeting of the Contractor Management Team and the Integrated Project Team for both contractor and DOE risks to schedule and cost. At that time, the contractor cost and schedule risk value was $41.3M and the DOE cost and schedule risk contingency value is$39.0M. The contractor cost and schedule risk value of $41.3M was retained in the performance baseline as the contractor's management reserve for risk contingency. The DOE cost and schedule risk value of$39.0M has been retained in the performance baseline as the DOE Contingency. The performance baseline for the project was approved in December 2006 (Garman 2006). The project will continue to manage to the performance baseline and change control thresholds identified in PLN-1963, ''Idaho Cleanup Project Sodium-Bearing Waste Treatment Project Execution Plan'' (PEP).
6. Evaluation of plan quality assurance models for prostate cancer patients based on fully automatically generated Pareto-optimal treatment plans
Science.gov (United States)
Wang, Yibing; Breedveld, Sebastiaan; Heijmen, Ben; Petit, Steven F.
2016-06-01
IMRT planning with commercial Treatment Planning Systems (TPSs) is a trial-and-error process. Consequently, the quality of treatment plans may not be consistent among patients, planners and institutions. Recently, different plan quality assurance (QA) models have been proposed, that could flag and guide improvement of suboptimal treatment plans. However, the performance of these models was validated using plans that were created using the conventional trail-and-error treatment planning process. Consequently, it is challenging to assess and compare quantitatively the accuracy of different treatment planning QA models. Therefore, we created a golden standard dataset of consistently planned Pareto-optimal IMRT plans for 115 prostate patients. Next, the dataset was used to assess the performance of a treatment planning QA model that uses the overlap volume histogram (OVH). 115 prostate IMRT plans were fully automatically planned using our in-house developed TPS Erasmus-iCycle. An existing OVH model was trained on the plans of 58 of the patients. Next it was applied to predict DVHs of the rectum, bladder and anus of the remaining 57 patients. The predictions were compared with the achieved values of the golden standard plans for the rectum D mean, V 65, and V 75, and D mean of the anus and the bladder. For the rectum, the prediction errors (predicted-achieved) were only -0.2 ± 0.9 Gy (mean ± 1 SD) for D mean,-1.0 ± 1.6% for V 65, and -0.4 ± 1.1% for V 75. For D mean of the anus and the bladder, the prediction error was 0.1 ± 1.6 Gy and 4.8 ± 4.1 Gy, respectively. Increasing the training cohort to 114 patients only led to minor improvements. A dataset of consistently planned Pareto-optimal prostate IMRT plans was generated. This dataset can be used to train new, and validate and compare existing treatment planning QA models, and has been made publicly available. The OVH model was highly accurate
7. Evaluation of plan quality assurance models for prostate cancer patients based on fully automatically generated Pareto-optimal treatment plans
Science.gov (United States)
Wang, Yibing; Breedveld, Sebastiaan; Heijmen, Ben; Petit, Steven F.
2016-06-01
IMRT planning with commercial Treatment Planning Systems (TPSs) is a trial-and-error process. Consequently, the quality of treatment plans may not be consistent among patients, planners and institutions. Recently, different plan quality assurance (QA) models have been proposed, that could flag and guide improvement of suboptimal treatment plans. However, the performance of these models was validated using plans that were created using the conventional trail-and-error treatment planning process. Consequently, it is challenging to assess and compare quantitatively the accuracy of different treatment planning QA models. Therefore, we created a golden standard dataset of consistently planned Pareto-optimal IMRT plans for 115 prostate patients. Next, the dataset was used to assess the performance of a treatment planning QA model that uses the overlap volume histogram (OVH). 115 prostate IMRT plans were fully automatically planned using our in-house developed TPS Erasmus-iCycle. An existing OVH model was trained on the plans of 58 of the patients. Next it was applied to predict DVHs of the rectum, bladder and anus of the remaining 57 patients. The predictions were compared with the achieved values of the golden standard plans for the rectum D mean, V 65, and V 75, and D mean of the anus and the bladder. For the rectum, the prediction errors (predicted–achieved) were only ‑0.2 ± 0.9 Gy (mean ± 1 SD) for D mean,‑1.0 ± 1.6% for V 65, and ‑0.4 ± 1.1% for V 75. For D mean of the anus and the bladder, the prediction error was 0.1 ± 1.6 Gy and 4.8 ± 4.1 Gy, respectively. Increasing the training cohort to 114 patients only led to minor improvements. A dataset of consistently planned Pareto-optimal prostate IMRT plans was generated. This dataset can be used to train new, and validate and compare existing treatment planning QA models, and has been made publicly available. The OVH model was highly
8. Registration and planning of radiotherapy and proton therapy treatment
International Nuclear Information System (INIS)
Within the frame of an update and renewal project, the Orsay Proton Therapy Centre of the Curie Institute (IPCO) renews its software used for the treatment of patients by proton therapy, a radiotherapy technique which uses proton beams. High energies used in these treatments and the precision provided by proton particle characteristics require a more precise patient positioning than conventional radiotherapy: proton therapy requires a precision of about a millimetre. Thus, markers are placed on the skull which are generally well accepted by patients, but are a problem in the case of paediatric treatment, notably for the youngest children whose skull is still growing. The first objective of this research is thus to use only intrinsic information from X-ray images used when positioning the patient. A second objective is to make the new software (TPS Isogray) perfectly compatible with IPCO requirements by maintaining the strengths of the previous TPS (Treatment Planning System) and being prepared to the implementation of a new installation. After a presentation of the context and state of the art in radiotherapy and patient positioning, the author proposes an overview of 2D registration methods, presents a new method for 2x2D registration, and addresses the problem of 3D registration. Then, after a presentation of proton therapy, the author addresses different specific issues and aspects: the compensator (simulation, calculation, and tests), dose calculation, the 'Pencil-Beam' algorithm, tests, and introduced improvements
9. Treatment planning for radiotherapy with very high-energy electron beams and comparison of VHEE and VMAT plans
Energy Technology Data Exchange (ETDEWEB)
Bazalova-Carter, Magdalena; Qu, Bradley; Palma, Bianey; Jensen, Christopher; Maxim, Peter G., E-mail: [email protected], E-mail: [email protected]; Loo, Billy W., E-mail: [email protected], E-mail: [email protected] [Department of Radiation Oncology, Stanford University, Stanford, California 94305 (United States); Hårdemark, Björn; Hynning, Elin [RaySearch Laboratories AB, Stockholm SE-103 65 (Sweden)
2015-05-15
Purpose: The aim of this work was to develop a treatment planning workflow for rapid radiotherapy delivered with very high-energy electron (VHEE) scanning pencil beams of 60–120 MeV and to study VHEE plans as a function of VHEE treatment parameters. Additionally, VHEE plans were compared to clinical state-of-the-art volumetric modulated arc therapy (VMAT) photon plans for three cases. Methods: VHEE radiotherapy treatment planning was performed by linking EGSnrc Monte Carlo (MC) dose calculations with inverse treatment planning in a research version of RayStation. In order to study the effect of VHEE treatment parameters on VHEE dose distributions, a MATLAB graphical user interface (GUI) for calculation of VHEE MC pencil beam doses was developed. Through the GUI, pediatric case MC simulations were run for a number of beam energies (60, 80, 100, and 120 MeV), number of beams (13, 17, and 36), pencil beam spot (0.1, 1.0, and 3.0 mm) and grid (2.0, 2.5, and 3.5 mm) sizes, and source-to-axis distance, SAD (40 and 50 cm). VHEE plans for the pediatric case calculated with the different treatment parameters were optimized and compared. Furthermore, 100 MeV VHEE plans for the pediatric case, a lung, and a prostate case were calculated and compared to the clinically delivered VMAT plans. All plans were normalized such that the 100% isodose line covered 95% of the target volume. Results: VHEE beam energy had the largest effect on the quality of dose distributions of the pediatric case. For the same target dose, the mean doses to organs at risk (OARs) decreased by 5%–16% when planned with 100 MeV compared to 60 MeV, but there was no further improvement in the 120 MeV plan. VHEE plans calculated with 36 beams outperformed plans calculated with 13 and 17 beams, but to a more modest degree (<8%). While pencil beam spacing and SAD had a small effect on VHEE dose distributions, 0.1–3 mm pencil beam sizes resulted in identical dose distributions. For the 100 MeV VHEE pediatric
10. SU-D-BRD-01: Cloud-Based Radiation Treatment Planning: Performance Evaluation of Dose Calculation and Plan Optimization
Energy Technology Data Exchange (ETDEWEB)
Na, Y; Kapp, D; Kim, Y; Xing, L [Stanford University School of Medicine, Stanford, CA (United States); Suh, T [Catholic UniversityMedical College, Seoul, Seoul (Korea, Republic of)
2014-06-01
Purpose: To report the first experience on the development of a cloud-based treatment planning system and investigate the performance improvement of dose calculation and treatment plan optimization of the cloud computing platform. Methods: A cloud computing-based radiation treatment planning system (cc-TPS) was developed for clinical treatment planning. Three de-identified clinical head and neck, lung, and prostate cases were used to evaluate the cloud computing platform. The de-identified clinical data were encrypted with 256-bit Advanced Encryption Standard (AES) algorithm. VMAT and IMRT plans were generated for the three de-identified clinical cases to determine the quality of the treatment plans and computational efficiency. All plans generated from the cc-TPS were compared to those obtained with the PC-based TPS (pc-TPS). The performance evaluation of the cc-TPS was quantified as the speedup factors for Monte Carlo (MC) dose calculations and large-scale plan optimizations, as well as the performance ratios (PRs) of the amount of performance improvement compared to the pc-TPS. Results: Speedup factors were improved up to 14.0-fold dependent on the clinical cases and plan types. The computation times for VMAT and IMRT plans with the cc-TPS were reduced by 91.1% and 89.4%, respectively, on average of the clinical cases compared to those with pc-TPS. The PRs were mostly better for VMAT plans (1.0 ≤ PRs ≤ 10.6 for the head and neck case, 1.2 ≤ PRs ≤ 13.3 for lung case, and 1.0 ≤ PRs ≤ 10.3 for prostate cancer cases) than for IMRT plans. The isodose curves of plans on both cc-TPS and pc-TPS were identical for each of the clinical cases. Conclusion: A cloud-based treatment planning has been setup and our results demonstrate the computation efficiency of treatment planning with the cc-TPS can be dramatically improved while maintaining the same plan quality to that obtained with the pc-TPS. This work was supported in part by the National Cancer Institute (1
11. A new method for commissioning Monte Carlo treatment planning systems
Science.gov (United States)
Aljarrah, Khaled Mohammed
2005-11-01
The Monte Carlo method is an accurate method for solving numerical problems in different fields. It has been used for accurate radiation dose calculation for radiation treatment of cancer. However, the modeling of an individual radiation beam produced by a medical linear accelerator for Monte Carlo dose calculation, i.e., the commissioning of a Monte Carlo treatment planning system, has been the bottleneck for the clinical implementation of Monte Carlo treatment planning. In this study a new method has been developed to determine the parameters of the initial electron beam incident on the target for a clinical linear accelerator. The interaction of the initial electron beam with the accelerator target produces x-ray and secondary charge particles. After successive interactions in the linac head components, the x-ray photons and the secondary charge particles interact with the patient's anatomy and deliver dose to the region of interest. The determination of the initial electron beam parameters is important for estimating the delivered dose to the patients. These parameters, such as beam energy and radial intensity distribution, are usually estimated through a trial and error process. In this work an easy and efficient method was developed to determine these parameters. This was accomplished by comparing calculated 3D dose distributions for a grid of assumed beam energies and radii in a water phantom with measurements data. Different cost functions were studied to choose the appropriate function for the data comparison. The beam parameters were determined on the light of this method. Due to the assumption that same type of linacs are exactly the same in their geometries and only differ by the initial phase space parameters, the results of this method were considered as a source data to commission other machines of the same type.
12. A DVH-guided IMRT optimization algorithm for automatic treatment planning and adaptive radiotherapy replanning
International Nuclear Information System (INIS)
Purpose: To develop a novel algorithm that incorporates prior treatment knowledge into intensity modulated radiation therapy optimization to facilitate automatic treatment planning and adaptive radiotherapy (ART) replanning. Methods: The algorithm automatically creates a treatment plan guided by the DVH curves of a reference plan that contains information on the clinician-approved dose-volume trade-offs among different targets/organs and among different portions of a DVH curve for an organ. In ART, the reference plan is the initial plan for the same patient, while for automatic treatment planning the reference plan is selected from a library of clinically approved and delivered plans of previously treated patients with similar medical conditions and geometry. The proposed algorithm employs a voxel-based optimization model and navigates the large voxel-based Pareto surface. The voxel weights are iteratively adjusted to approach a plan that is similar to the reference plan in terms of the DVHs. If the reference plan is feasible but not Pareto optimal, the algorithm generates a Pareto optimal plan with the DVHs better than the reference ones. If the reference plan is too restricting for the new geometry, the algorithm generates a Pareto plan with DVHs close to the reference ones. In both cases, the new plans have similar DVH trade-offs as the reference plans. Results: The algorithm was tested using three patient cases and found to be able to automatically adjust the voxel-weighting factors in order to generate a Pareto plan with similar DVH trade-offs as the reference plan. The algorithm has also been implemented on a GPU for high efficiency. Conclusions: A novel prior-knowledge-based optimization algorithm has been developed that automatically adjust the voxel weights and generate a clinical optimal plan at high efficiency. It is found that the new algorithm can significantly improve the plan quality and planning efficiency in ART replanning and automatic treatment
13. Specification and acceptance testing of radiotherapy treatment planning systems
International Nuclear Information System (INIS)
Quality assurance (QA) in the radiation therapy treatment planning process is essential to ensure accurate dose delivery to the patient and to minimize the possibility of accidental exposure. The computerized radiotherapy treatment planning systems (RTPSs) are now widely available in industrialized and developing countries and it is of special importance to support hospitals in Member States in developing procedures for acceptance testing, commissioning and QA of their RTPSs. Responding to these needs, a group of experts developed an IAEA publication with such recommendations, which was published in 2004 as IAEA Technical Reports Series No. 430. This report provides a general framework and describes a large number of tests and procedures that should be considered by the users of new RTPSs. However, small hospitals with limited resources or large hospitals with high patient load and limited staff are not always able to perform complete characterization, validation and software testing of algorithms used in RTPSs. Therefore, the IAEA proposed more specific guidelines that provide a step-by-step recommendation for users at hospitals or cancer centres how to implement acceptance and commissioning procedures for newly purchased RTPSs. The current publication was developed in the framework of the Coordinated Research Project on Development of Procedures for Quality Assurance for Dosimetry Calculations in Radiotherapy and uses the International Electrotechnical Commission (IEC) standard IEC 62083, Requirements for the Safety of Radiotherapy Treatment Planning Systems as its basis. The report addresses the procedures for specification and acceptance testing of RTPSs to be used by both manufacturers and users at the hospitals. Recommendations are provided for specific tests to be performed at the manufacturing facility known as type tests, and for acceptance tests to be performed at the hospital known as site tests. The purpose of acceptance testing is to demonstrate to the
14. Technical Basis for Radiological Emergency Plan Annex for WTD Emergency Response Plan: West Point Treatment Plant
Energy Technology Data Exchange (ETDEWEB)
Hickey, Eva E.; Strom, Daniel J.
2005-08-01
Staff of the King County Wastewater Treatment Division (WTD) have concern about the aftermath of a radiological dispersion event (RDE) leading to the introduction of significant quantities of radioactive material into the combined sanitary and storm sewer system in King County, Washington. Radioactive material could come from the use of a radiological dispersion device (RDD). RDDs include "dirty bombs" that are not nuclear detonations but are explosives designed to spread radioactive material (National Council on Radiation Protection and Measurements (NCRP) 2001). Radioactive material also could come from deliberate introduction or dispersion of radioactive material into the environment, including waterways and water supply systems. This document, Volume 3 of PNNL-15163 is the technical basis for the Annex to the West Point Treatment Plant (WPTP) Emergency Response Plan related to responding to a radiological emergency at the WPTP. The plan primarily considers response to radioactive material that has been introduced in the other combined sanitary and storm sewer system from a radiological dispersion device, but is applicable to any accidental or deliberate introduction of materials into the system.
15. Groups as a part of integrated treatment plans : Inpatient psychotherapy for outpatients?
NARCIS (Netherlands)
Staats, H
2005-01-01
Group psychotherapy in Germany is well established as part of an integrative treatment plan in inpatient treatment. Outpatient group psychotherapy, however, is conceptualized as a separate treatment option in competition with individual therapy. German guidelines for outpatient psychotherapy exclude
16. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan
International Nuclear Information System (INIS)
The Hanford Site, located northwest of the city of Richland, Washington, houses reactors, chemical-separation systems, and related facilities used for the production of special nuclear materials, as well as for activities associated with nuclear energy development. The 300 Area of the Hanford Site contains reactor fuel manufacturing facilities and several research and development laboratories. The 3718-F Alkali Metal Treatment and Storage Facility (3718-F Facility), located in the 300 Area, was used to store and treat alkali metal wastes. Therefore, it is subject to the regulatory requirements for the storage and treatment of dangerous wastes. Closure will be conducted pursuant to the requirements of the Washington Administrative Code (WAC) 173-303-610 (Ecology 1989) and 40 CFR 270.1. Closure also will satisfy the thermal treatment facility closure requirements of 40 CFR 265.381. This closure plan presents a description of the 3718-F Facility, the history of wastes managed, and the approach that will be followed to close the facility. Only hazardous constituents derived from 3718-F Facility operations will be addressed
17. A comparison of neutron beams for BNCT based on in-phantom neutron field assessment parameters
International Nuclear Information System (INIS)
In this paper our in-phantom neutron field assessment parameters, T and DTumor, were used to evaluate several neutron sources for use in BNCT. Specifically, neutron fields from The Ohio State University (OSU) Accelerator-Based Neutron Source (ABNS) design, two alternative ABNS designs from the literature (the Al/AlF3-Al2O3 ABNS and the 7LiF-Al2O3 ABNS), a fission-convertor plate concept based on the 500-kW OSU Research Reactor (OSURR), and the Brookhaven Medical Research Reactor (BMRR) facility were evaluated. In order to facilitate a comparison of the various neutron fields, values of T and DTumor were calculated in a 14 cmx14 cmx14 cm lucite cube phantom located in the treatment port of each neutron source. All of the other relevant factors, such as phantom materials, kerma factors, and treatment parameters, were kept the same. The treatment times for the OSURR, the 7LiF-Al2O3 ABNS operating at a beam current of 10 mA, and the BMRR were calculated to be comparable and acceptable, with a treatment time per fraction of approximately 25 min for a four fraction treatment scheme. The treatment time per fraction for the OSU ABNS and the Al/AlF3-Al2O3 ABNS can be reduced to below 30 min per fraction for four fractions, if the proton beam current is made greater than approximately 20 mA. DTumor was calculated along the beam centerline for tumor depths in the phantom ranging from 0 to 14 cm. For tumor depths ranging from 0 to approximately 1.5 cm, the value of DTumor for the OSURR is largest, while for tumor depths ranging from 1.5 to approximately 14 cm, the value of DTumor for the OSU-ABNS is the largest
18. The 300 area waste acid treatment system closure plan
International Nuclear Information System (INIS)
The 300 Area Waste Acid Treatment System (WATS) is located within operable units 300-FF-2 (source) and 300-FF-5 (groundwater), as designated in the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) . Operable units 300-FF-2 and 300-FF-5 are scheduled to be remediated using the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) Remedial Investigation/Feasibility Study (RI/FS) process. Thus, any remediation of the 300 Area WATS with respect to contaminants not produced by those facilities and soils and groundwater will be deferred to the CERCLA RI/FS process. Final closure activities will be completed in 3 phases and certified in accordance with the 300 Area WATS closure plan by the Washington State Department of Ecology (Ecology) and the U.S. Environmental Protection Agency (EPA). It is anticipated that the 300 Area WATS closure would take 2 years to complete
19. CBCT analysis of three implant cases for treatment planning
Energy Technology Data Exchange (ETDEWEB)
Kim, Jae Duk; Kim, Kwang Won; Lim, Sung Hoon [Chosun Univ. School of Dentistry, Gwangju (Korea, Republic of)
2007-09-15
The role of radiographic imaging in determining the size, numbers and the position of implants is very important. To perform the implant procedure, the dentist needs to evaluate the bone pathology and bone density, and to know the precise height, width, and contour of the alveolar process, as well as its relationship to the maxillary sinus and mandibular canal. The author analyzed 3 implant cases for treatment planning with the cone beam CT. All axial, panoramic, serial and buccolingual-sectioned images of 3 cases with stent including vertical marker were taken by using Mercury (Hitachi, Japan). When the curved line drawn intentionally did nor include dot image of a vertical marker on the axial image of CBCT, the image of the vertical marker was deformed on its buccolingually sectioned image. There was wide discrepancy in inclination between the alveolar bone and tooth on buccolingually sectioned image.
20. Inverse treatment planning for spinal robotic radiosurgery: an international multi-institutional benchmark trial.
Science.gov (United States)
Blanck, Oliver; Wang, Lei; Baus, Wolfgang; Grimm, Jimm; Lacornerie, Thomas; Nilsson, Joakim; Luchkovskyi, Sergii; Palazon Cano, Isabel; Shou, Zhenyu; Ayadi, Myriam; Treuer, Harald; Viard, Romain; Siebert, Frank-Andre; Chan, Mark K H; Hildebrandt, Guido; Dunst, Jürgen; Imhoff, Detlef; Wurster, Stefan; Wolff, Robert; Romanelli, Pantaleo; Lartigau, Eric; Semrau, Robert; Soltys, Scott G; Schweikard, Achim
2016-01-01
Stereotactic radiosurgery (SRS) is the accurate, conformal delivery of high-dose radiation to well-defined targets while minimizing normal structure doses via steep dose gradients. While inverse treatment planning (ITP) with computerized optimization algorithms are routine, many aspects of the planning process remain user-dependent. We performed an international, multi-institutional benchmark trial to study planning variability and to analyze preferable ITP practice for spinal robotic radiosurgery. 10 SRS treatment plans were generated for a complex-shaped spinal metastasis with 21 Gy in 3 fractions and tight constraints for spinal cord (V14Gy 95%). The resulting plans were rated on a scale from 1 to 4 (excellent-poor) in five categories (constraint compliance, optimization goals, low-dose regions, ITP complexity, and clinical acceptability) by a blinded review panel. Additionally, the plans were mathemati-cally rated based on plan indices (critical structure and target doses, conformity, monitor units, normal tissue complication probability, and treatment time) and compared to the human rankings. The treatment plans and the reviewers' rankings varied substantially among the participating centers. The average mean overall rank was 2.4 (1.2-4.0) and 8/10 plans were rated excellent in at least one category by at least one reviewer. The mathematical rankings agreed with the mean overall human rankings in 9/10 cases pointing toward the possibility for sole mathematical plan quality comparison. The final rankings revealed that a plan with a well-balanced trade-off among all planning objectives was preferred for treatment by most par-ticipants, reviewers, and the mathematical ranking system. Furthermore, this plan was generated with simple planning techniques. Our multi-institutional planning study found wide variability in ITP approaches for spinal robotic radiosurgery. The participants', reviewers', and mathematical match on preferable treatment plans and ITP
1. Inverse treatment planning for spinal robotic radiosurgery: an international multi-institutional benchmark trial.
Science.gov (United States)
Blanck, Oliver; Wang, Lei; Baus, Wolfgang; Grimm, Jimm; Lacornerie, Thomas; Nilsson, Joakim; Luchkovskyi, Sergii; Palazon Cano, Isabel; Shou, Zhenyu; Ayadi, Myriam; Treuer, Harald; Viard, Romain; Siebert, Frank-Andre; Chan, Mark K H; Hildebrandt, Guido; Dunst, Jürgen; Imhoff, Detlef; Wurster, Stefan; Wolff, Robert; Romanelli, Pantaleo; Lartigau, Eric; Semrau, Robert; Soltys, Scott G; Schweikard, Achim
2016-01-01
Stereotactic radiosurgery (SRS) is the accurate, conformal delivery of high-dose radiation to well-defined targets while minimizing normal structure doses via steep dose gradients. While inverse treatment planning (ITP) with computerized optimization algorithms are routine, many aspects of the planning process remain user-dependent. We performed an international, multi-institutional benchmark trial to study planning variability and to analyze preferable ITP practice for spinal robotic radiosurgery. 10 SRS treatment plans were generated for a complex-shaped spinal metastasis with 21 Gy in 3 fractions and tight constraints for spinal cord (V14Gy 95%). The resulting plans were rated on a scale from 1 to 4 (excellent-poor) in five categories (constraint compliance, optimization goals, low-dose regions, ITP complexity, and clinical acceptability) by a blinded review panel. Additionally, the plans were mathemati-cally rated based on plan indices (critical structure and target doses, conformity, monitor units, normal tissue complication probability, and treatment time) and compared to the human rankings. The treatment plans and the reviewers' rankings varied substantially among the participating centers. The average mean overall rank was 2.4 (1.2-4.0) and 8/10 plans were rated excellent in at least one category by at least one reviewer. The mathematical rankings agreed with the mean overall human rankings in 9/10 cases pointing toward the possibility for sole mathematical plan quality comparison. The final rankings revealed that a plan with a well-balanced trade-off among all planning objectives was preferred for treatment by most par-ticipants, reviewers, and the mathematical ranking system. Furthermore, this plan was generated with simple planning techniques. Our multi-institutional planning study found wide variability in ITP approaches for spinal robotic radiosurgery. The participants', reviewers', and mathematical match on preferable treatment plans and ITP
2. The effect of bruxism on treatment planning for dental implants.
Science.gov (United States)
Misch, Carl E
2002-09-01
Bruxism is a potential risk factor for implant failure. Excessive force is the primary cause of late implant complications. An appreciation of the etiology of crestal bone loss, failure of implants, failure to retain implant restorations, and fracture of components will lead the practitioner to develop a treatment plan that reduces force on implants and their restorations. The forces are considered in terms of magnitude, duration, direction, type, and magnification. Once the dentist has identified the source(s) of additional force on the implant system, the treatment plan is altered to contend with and reduce the negative sequelae on the bone, implant, and final restoration. One viable approach is to increase the implant-bone surface area. Additional implants can be placed to decrease stress on any one implant, and implants in molar regions should have an increased width. Use of more and wider implants decreases the strain on the prosthesis and also dissipates stress to the bone, especially at the crest. The additional implants should be positioned with intent to eliminate cantilevers when possible. Greater surface area implant designs made of titanium alloy and with an external hex design can also prove advantageous. Anterior guidance in mandibular excursions further decreases force and eliminates or reduces lateral posterior force. Metal occlusal surfaces decrease the risk of porcelain fracture and do not require as much abutment reduction, which in turn enhances prosthesis retention. The retention of the final prosthesis or super-structure is also improved with additional implant abutments. Night guards designed with specific features also are a benefit to initially diagnose the influence of occlusal factors for the patient, and as importantly, to reduce the influence of extraneous stress on implants and implant-retained restorations. PMID:12271847
3. Investigating the robustness of ion beam therapy treatment plans to uncertainties in biological treatment parameters
CERN Document Server
Boehlen, T T; Dosanjh, M; Ferrari, A; Fossati, P; Haberer, T; Mairani, A; Patera, V
2012-01-01
Uncertainties in determining clinically used relative biological effectiveness (RBE) values for ion beam therapy carry the risk of absolute and relative misestimations of RBE-weighted doses for clinical scenarios. This study assesses the consequences of hypothetical misestimations of input parameters to the RBE modelling for carbon ion treatment plans by a variational approach. The impact of the variations on resulting cell survival and RBE values is evaluated as a function of the remaining ion range. In addition, the sensitivity to misestimations in RBE modelling is compared for single fields and two opposed fields using differing optimization criteria. It is demonstrated for single treatment fields that moderate variations (up to +/-50\\%) of representative nominal input parameters for four tumours result mainly in a misestimation of the RBE-weighted dose in the planning target volume (PTV) by a constant factor and only smaller RBE-weighted dose gradients. Ensuring a more uniform radiation quality in the PTV...
4. Sci—Thur PM: Planning and Delivery — 02: Treatment planning workflow for very high-energy electron beam radiotherapy
Energy Technology Data Exchange (ETDEWEB)
Bazalova, Magdalena; Qu, Bradley; Palma, Bianey; Maxim, Peter; Loo, Billy [Stanford University, Stanford, CA (United States); Hårdemark, Bjorn; Hynning, Elin [RaySearch Laboratories AB, Stockholm (Sweden)
2014-08-15
Purpose: To develop treatment planning workflow for rapid radiotherapy delivered with very-high energy electron (VHEE) scanning beam. Methods: VHEE radiotherapy treatment planning was performed by linking Monte Carlo (MC) dose calculations with inverse optimization in a research version of RayStation. In order to study a number of treatment parameters, a Matlab graphical user interface (GUI) for calculation of VHEE beamlet dose was developed. Through the GUI, EGSnrc MC simulations were run for a number of beam energies, number of beams, beamlet spot and grid sizes, and machine bore sizes. VHEE plans for a pediatric patient with a 4.3 cm{sup 3} brain target optimized with spot-scanning algorithm in RayStation were compared to the clinically delivered 6 MV VMAT plan. Results and Discussion: VHEE beam energy had the largest effect on the quality of dose distributions. For the same target dose, the mean doses to critical organs decreased by 10–15% when planned with 100 MeV compared to 60 MeV. VHEE plans calculated with 36 beams outperformed plans calculated with 13 and 17 beams. While beamlet spacing and bore size had a small effect on VHEE dose distributions, 0.1-3mm beamlet sizes resulted in identical dose distributions. Critical organ doses were by up to 70% lower in the best VHEE plan compared to the clinical 6 MV VMAT plan. Conclusions: We have developed a GUI for MC beamlet generation for treatment planning of VHEE radiotherapy. We have demonstrated that pediatric VHEE plans resulted in significant critical organ dose sparing compared to the clinical VMAT plan.
5. Rational design of antibiotic treatment plans: a treatment strategy for managing evolution and reversing resistance.
Directory of Open Access Journals (Sweden)
Portia M Mira
Full Text Available The development of reliable methods for restoring susceptibility after antibiotic resistance arises has proven elusive. A greater understanding of the relationship between antibiotic administration and the evolution of resistance is key to overcoming this challenge. Here we present a data-driven mathematical approach for developing antibiotic treatment plans that can reverse the evolution of antibiotic resistance determinants. We have generated adaptive landscapes for 16 genotypes of the TEM β-lactamase that vary from the wild type genotype "TEM-1" through all combinations of four amino acid substitutions. We determined the growth rate of each genotype when treated with each of 15 β-lactam antibiotics. By using growth rates as a measure of fitness, we computed the probability of each amino acid substitution in each β-lactam treatment using two different models named the Correlated Probability Model (CPM and the Equal Probability Model (EPM. We then performed an exhaustive search through the 15 treatments for substitution paths leading from each of the 16 genotypes back to the wild type TEM-1. We identified optimized treatment paths that returned the highest probabilities of selecting for reversions of amino acid substitutions and returning TEM to the wild type state. For the CPM model, the optimized probabilities ranged between 0.6 and 1.0. For the EPM model, the optimized probabilities ranged between 0.38 and 1.0. For cyclical CPM treatment plans in which the starting and ending genotype was the wild type, the probabilities were between 0.62 and 0.7. Overall this study shows that there is promise for reversing the evolution of resistance through antibiotic treatment plans.
6. Rational Design of Antibiotic Treatment Plans: A Treatment Strategy for Managing Evolution and Reversing Resistance
Science.gov (United States)
Mira, Portia M.; Crona, Kristina; Greene, Devin; Meza, Juan C.; Sturmfels, Bernd; Barlow, Miriam
2015-01-01
The development of reliable methods for restoring susceptibility after antibiotic resistance arises has proven elusive. A greater understanding of the relationship between antibiotic administration and the evolution of resistance is key to overcoming this challenge. Here we present a data-driven mathematical approach for developing antibiotic treatment plans that can reverse the evolution of antibiotic resistance determinants. We have generated adaptive landscapes for 16 genotypes of the TEM β-lactamase that vary from the wild type genotype “TEM-1” through all combinations of four amino acid substitutions. We determined the growth rate of each genotype when treated with each of 15 β-lactam antibiotics. By using growth rates as a measure of fitness, we computed the probability of each amino acid substitution in each β-lactam treatment using two different models named the Correlated Probability Model (CPM) and the Equal Probability Model (EPM). We then performed an exhaustive search through the 15 treatments for substitution paths leading from each of the 16 genotypes back to the wild type TEM-1. We identified optimized treatment paths that returned the highest probabilities of selecting for reversions of amino acid substitutions and returning TEM to the wild type state. For the CPM model, the optimized probabilities ranged between 0.6 and 1.0. For the EPM model, the optimized probabilities ranged between 0.38 and 1.0. For cyclical CPM treatment plans in which the starting and ending genotype was the wild type, the probabilities were between 0.62 and 0.7. Overall this study shows that there is promise for reversing the evolution of resistance through antibiotic treatment plans. PMID:25946134
7. Organisation and management of the first clinical trial of BNCT in Europe (EORTC Protocol 11961)
International Nuclear Information System (INIS)
Boron Neutron Capture Therapy is based on the ability of the isotope 10B to capture thermal neutrons and to disintegrate instantaneously producing high LET particles. The only neutron beam available in Europe for such a treatment is based at the European High Flux Reactor HFR at Petten (The Netherlands). The European Commission, owners of the reactor, decided that the potential benefit of the facility should be opened to all European citizens and therefore insisted on a multinational approach to perform the first clinical trial in Europe on BNCT. This precondition had to be respected as well as the national laws and regulations. Together with the Dutch authorities actions were undertaken to overcome the obvious legal problems. Furthermore, the clinical trial at Petten takes place in a nuclear research reactor, which apart from being conducted in a non-hospital environment, is per se known to be dangerous. It was therefore of the utmost importance that special attention is given to safety, beyond normal rules, and to the training of staff. In itself, the trial is an unusual Phase I study, introducing a new drug with a new irradiation modality, with really an unknown dose-effect relationship. This trial must follow optimal procedures, which underscore the quality and qualified manner of performance. (orig.)
8. A feasibility study of the Tehran research reactor as a neutron source for BNCT.
Science.gov (United States)
Kasesaz, Yaser; Khalafi, Hossein; Rahmani, Faezeh; Ezati, Arsalan; Keyvani, Mehdi; Hossnirokh, Ashkan; Shamami, Mehrdad Azizi; Monshizadeh, Mahdi
2014-08-01
Investigation on the use of the Tehran Research Reactor (TRR) as a neutron source for Boron Neutron Capture Therapy (BNCT) has been performed by calculating and measuring energy spectrum and the spatial distribution of neutrons in all external irradiation facilities, including six beam tubes, thermal column, and the medical room. Activation methods with multiple foils and a copper wire have been used for the mentioned measurements. The results show that (1) the small diameter and long length beam tubes cannot provide sufficient neutron flux for BNCT; (2) in order to use the medical room, the TRR core should be placed in the open pool position, in this situation the distance between the core and patient position is about 400 cm, so neutron flux cannot be sufficient for BNCT; and (3) the best facility which can be adapted for BNCT application is the thermal column, if all graphite blocks can be removed. The epithermal and fast neutron flux at the beginning of this empty column are 4.12×10(9) and 1.21×10(9) n/cm(2)/s, respectively, which can provide an appropriate neutron beam for BNCT by designing and constructing a proper Beam Shaping Assembly (BSA) structure.
9. SU-E-T-575: Isocenter Shifts in Treatment Planning and Its Clinical Implications
Energy Technology Data Exchange (ETDEWEB)
Ahmed, Y; Damiani, S; Cao, Y; Jamshidi, A [Long Island Jewish Medical Center, New Hyde Park, NY (United States)
2014-06-01
Purpose: To investigate causes of isocenter shifts in treatment planning and its clinical impact on patient treatment efficiency and safety. Methods/Materials: Treatment planning data of 340 patients under treatment over 8 weeks period were gathered to identify isocenter shifts according to site of the treatment, types of treatment plan or types of the machine used. Treatment plans included inversed and forward IMRT, as well as 3D plans. Treatment sites included pelvis, chest, abdomen, breasts, head and necks and extremities. Re-planning were performed without the isocenter shift for pelvis and chest plans, the dosimetric parameters such as PTV coverage, and dose sparing of OARs of these plans were analyzed and compared. Results/Discussions: Results showed that the isocenter shift was always necessary for some of sites such as breasts, two or more distinctive PTVs, or special cases such as large PTV treated with enhanced dynamic wedge. Many other cases, the re-planning results indicated 53% of the plans that the same quality of the plan can be achieved without the shift of the isocenter. Repositioning patients on a daily basis demanded unambiguous instructions for therapists for patient setups, and additional time to perform the shifts before treatment. Opportunities for error propagation exist during the communication and hand-over of such plans. Conclusion: Isocenter shifts demanded unambiguous instructions and times for therapists for daily patient setups, therefore it impacted both safety and efficiency of the patient treatment. Based on the analysis, the isocenter shifts were unavoidable for cases such as treatment of multiple sites, overcoming limitations of treatment machines, and/or sometime better dosimetry. However, we found many initially proposed shifts may have been eliminated either by careful planning or by improved CT simulation process such as detailed review of the images and localization of the PTV during simulation.
10. Functional and molecular image guidance in radiotherapy treatment planning optimization.
Science.gov (United States)
Das, Shiva K; Ten Haken, Randall K
2011-04-01
Functional and molecular imaging techniques are increasingly being developed and used to quantitatively map the spatial distribution of parameters, such as metabolism, proliferation, hypoxia, perfusion, and ventilation, onto anatomically imaged normal organs and tumor. In radiotherapy optimization, these imaging modalities offer the promise of increased dose sparing to high-functioning subregions of normal organs or dose escalation to selected subregions of the tumor as well as the potential to adapt radiotherapy to functional changes that occur during the course of treatment. The practical use of functional/molecular imaging in radiotherapy optimization must take into cautious consideration several factors whose influences are still not clearly quantified or well understood including patient positioning differences between the planning computed tomography and functional/molecular imaging sessions, image reconstruction parameters and techniques, image registration, target/normal organ functional segmentation, the relationship governing the dose escalation/sparing warranted by the functional/molecular image intensity map, and radiotherapy-induced changes in the image intensity map over the course of treatment. The clinical benefit of functional/molecular image guidance in the form of improved local control or decreased normal organ toxicity has yet to be shown and awaits prospective clinical trials addressing this issue. PMID:21356479
11. PyCMSXiO: an external interface to script treatment plans for the Elekta® CMS XiO treatment planning system
International Nuclear Information System (INIS)
Scripting in radiotherapy treatment planning systems not only simplifies routine planning tasks but can also be used for clinical research. Treatment planning scripting can only be utilized in a system that has a built-in scripting interface. Among the commercially available treatment planning systems, Pinnacle (Philips) and Raystation (Raysearch Lab.) have inherent scripting functionality. CMS XiO (Elekta) is a widely used treatment planning system in radiotherapy centres around the world, but it does not have an interface that allows the user to script radiotherapy plans. In this study an external scripting interface, PyCMSXiO, was developed for XiO using the Python programming language. The interface was implemented as a python package/library using a modern object-oriented programming methodology. The package was organized as a hierarchy of different classes (objects). Each class (object) corresponds to a plan object such as the beam of a clinical radiotherapy plan. The interface of classes was implemented as object functions. Scripting in XiO using PyCMSXiO is comparable with Pinnacle scripting. This scripting package has been used in several research projects including commissioning of a beam model, independent three-dimensional dose verification for IMRT plans and a setup-uncertainty study. Ease of use and high-level functions provided in the package achieve a useful research tool. It was released as an open-source tool that may benefit the medical physics community.
12. PyCMSXiO: an external interface to script treatment plans for the Elekta® CMS XiO treatment planning system
Science.gov (United States)
Xing, Aitang; Arumugam, Sankar; Holloway, Lois; Goozee, Gary
2014-03-01
Scripting in radiotherapy treatment planning systems not only simplifies routine planning tasks but can also be used for clinical research. Treatment planning scripting can only be utilized in a system that has a built-in scripting interface. Among the commercially available treatment planning systems, Pinnacle (Philips) and Raystation (Raysearch Lab.) have inherent scripting functionality. CMS XiO (Elekta) is a widely used treatment planning system in radiotherapy centres around the world, but it does not have an interface that allows the user to script radiotherapy plans. In this study an external scripting interface, PyCMSXiO, was developed for XiO using the Python programming language. The interface was implemented as a python package/library using a modern object-oriented programming methodology. The package was organized as a hierarchy of different classes (objects). Each class (object) corresponds to a plan object such as the beam of a clinical radiotherapy plan. The interface of classes was implemented as object functions. Scripting in XiO using PyCMSXiO is comparable with Pinnacle scripting. This scripting package has been used in several research projects including commissioning of a beam model, independent three-dimensional dose verification for IMRT plans and a setup-uncertainty study. Ease of use and high-level functions provided in the package achieve a useful research tool. It was released as an open-source tool that may benefit the medical physics community.
13. Treatment planning with functional MRI; Strahlentherapieplanung mit der funktionellen MRT
Energy Technology Data Exchange (ETDEWEB)
Georg, P. [EBG MedAustron GmbH, Wiener Neustadt (Austria); Medizinische Universitaet Wien, Christian Doppler Labor fuer die Medizinische Strahlenforschung, Wien (Austria); Andrzejewski, P.; Georg, D. [Medizinische Universitaet Wien, Christian Doppler Labor fuer die Medizinische Strahlenforschung, Wien (Austria); Medizinische Universitaet Wien, Abteilung fuer medizinische Strahlenphysik, Univ. Klinik fuer Strahlentherapie, Wien (Austria); Pinker, K. [Medizinische Universitaet Wien, Christian Doppler Labor fuer die Medizinische Strahlenforschung, Wien (Austria); Medizinische Universitaet Wien, Abteilung fuer molekulare Bildgebung, Univ. Klinik fuer Radiologie und Nuklearmedizin, Wien (Austria)
2015-12-15
The aim of magnetic resonance imaging (MRI) guided radiotherapy is high precision in treatment delivery. With new developments it is possible to focus the high dose irradiation on the tumor while sparing the surrounding tissue. The achievements in precision of the treatment planning and delivery warrant equally precise tumor definition. In conventional radiation therapy it is necessary to carry out a planning computed tomography (CT). For many tumors there is also need for an additional morphological MRI because of more accurate tumor definition. In standard radiotherapy the tumor volume is irradiated with a homogeneous dose. The aim of functional multiparametric MRI is to visualize and quantify biological, physiological and pathological processes at the cellular and molecular levels. Based on this information it is possible to elucidate tumor biology and identify subvolumes of more aggressive behavior. They are often radiotherapy-resistant, leading to tumor recurrence thus requiring further dose escalation. The concept of inhomogeneous tumor irradiation according to its biological behavior is called dose painting. Dose painting is technically feasible. The expected clinical benefit is motivated by selective treatment adaptations based on biological tumor characteristics. Tumors show variable response to therapy underlining the need for individual treatment plans. This approach may lead not only to higher local control but also to better sparing of normal surrounding tissue. With the clinical implementation of dose painting, improvements in the therapeutic outcome can be expected. Due to the existing technical challenges, extensive collaboration between radiation oncologists, radiologists, medical physicists and radiation biologists is needed. (orig.) [German] Die Strahlentherapieplanung mit der funktionellen Magnetresonanztomographie (fMRT) zielt auf eine Hochpraezisionsradiotherapie ab. Mit den modernen Technologien ist es moeglich, die Strahlentherapie nahezu
14. Automated planning of ablation targets in atrial fibrillation treatment
Science.gov (United States)
Keustermans, Johannes; De Buck, Stijn; Heidbüchel, Hein; Suetens, Paul
2011-03-01
Catheter based radio-frequency ablation is used as an invasive treatment of atrial fibrillation. This procedure is often guided by the use of 3D anatomical models obtained from CT, MRI or rotational angiography. During the intervention the operator accurately guides the catheter to prespecified target ablation lines. The planning stage, however, can be time consuming and operator dependent which is suboptimal both from a cost and health perspective. Therefore, we present a novel statistical model-based algorithm for locating ablation targets from 3D rotational angiography images. Based on a training data set of 20 patients, consisting of 3D rotational angiography images with 30 manually indicated ablation points, a statistical local appearance and shape model is built. The local appearance model is based on local image descriptors to capture the intensity patterns around each ablation point. The local shape model is constructed by embedding the ablation points in an undirected graph and imposing that each ablation point only interacts with its neighbors. Identifying the ablation points on a new 3D rotational angiography image is performed by proposing a set of possible candidate locations for each ablation point, as such, converting the problem into a labeling problem. The algorithm is validated using a leave-one-out-approach on the training data set, by computing the distance between the ablation lines obtained by the algorithm and the manually identified ablation points. The distance error is equal to 3.8+/-2.9 mm. As ablation lesion size is around 5-7 mm, automated planning of ablation targets by the presented approach is sufficiently accurate.
15. Subcellular boron and fluorine distributions with SIMS ion microscopy in BNCT and cancer research
Energy Technology Data Exchange (ETDEWEB)
Subhash Chandra
2008-05-30
The development of a secondary ion mass spectrometry (SIMS) based technique of Ion Microscopy in boron neutron capture therapy (BNCT) was the main goal of this project, so that one can study the subcellular location of boron-10 atoms and their partitioning between the normal and cancerous tissue. This information is fundamental for the screening of boronated drugs appropriate for neutron capture therapy of cancer. Our studies at Cornell concentrated mainly on studies of glioblastoma multiforme (GBM). The early years of the grant were dedicated to the development of cryogenic methods and correlative microscopic approaches so that a reliable subcellular analysis of boron-10 atoms can be made with SIMS. In later years SIMS was applied to animal models and human tissues of GBM for studying the efficacy of potential boronated agents in BNCT. Under this grant the SIMS program at Cornell attained a new level of excellence and collaborative SIMS studies were published with leading BNCT researchers in the U.S.
16. BNCT of 3 cases of spontaneous head and neck cancer in feline patients
Energy Technology Data Exchange (ETDEWEB)
Rao, M.; Trivillin, V.A.; Heber, E.M.; Angeles Cantarelli, Maria de los; Itoiz, M.E.; Nigg, D.W.; Rebagliati, R.J.; Batistoni, Daniel; Schwint, A.E. E-mail: [email protected]
2004-11-01
Having demonstrated BPA-BNCT induced control of experimental squamous cell carcinomas (SCC) of the hamster cheek pouch mucosa with no damage to normal tissue we explored the feasibility and safety of treating spontaneous head and neck tumors, with particular focus on SCC, of terminal feline patients with low dose BPA-BNCT employing the thermal beam of the RA-1 Reactor within a preclinical context. The biodistribution studies showed that, in all three cases evaluated, BPA delivered absolute boron values to tumor in the range that proved therapeutically useful in the experimental model of SCC. BPA-BNCT studies showed no radiotoxic effects, partial tumor control in terms of impaired growth and partial necrosis, an improvement in clinical condition and prolonged survival beyond the terminal condition of the feline patients at the time of recruitment.
17. INEL BNCT Program: Bulletin, Volume 5, No. 7
Energy Technology Data Exchange (ETDEWEB)
Ackermann, A.L. (ed.)
1991-07-01
This Bulletin presents a summary of accomplishments and highlights in the Idaho National Engineering Laboratory's (INEL) Boron Neutron Capture Therapy (BNCT) Program for June, 1991. This bulletin includes information on the brain tumor and melanoma research programs, Power Burst Facility (PBF) technical support and modifications, PBF operations, and animal data charts. Specific highlights include: final-dosage-form BSH samples were analyzed for purity, with the sample from Centronic Ltd the most free from contamination and oxidation products; MRI spectroscopy will be upgraded to provide a potential for boron resolution of 0.75 cm/pixel; neutron and gamma measurements were made for the HFR epithermal neutron beam; the current status of six spontaneous brain-tumor dogs; production of MoAbs against the pituitary CRF receptor; growth of BL6 in low Phe/Tyr medium; an altered synthetic pathway for carboranyl alanine; and encapsulation of {ital i}-B{sub 20}H{sub 18}{sup 2-} into liposomes for baseline murine studies. 2 figs., 4 tabs. (MHB)
18. Current clinical results of the Tsukuba BNCT trial
Energy Technology Data Exchange (ETDEWEB)
Yamamoto, T.; Matsumura, A. E-mail: [email protected]; Nakai, K.; Shibata, Y.; Endo, K.; Sakurai, F.; Kishi, T.; Kumada, H.; Yamamoto, K.; Torii, Y
2004-11-01
Nine high grade gliomas (5 glioblastomas and 4 anaplastic astrocytomas) were treated with BSH-based intaoperative boron neutron capture therapy (IOBNCT). BSH (100 mg/kg body weight) was intravenously injected, followed by single fraction irradiation using the mixed thermal/epithermal beam of Japan Research Reactor 4. The blood boron level at the time of irradiation averaged 29.9 (18.8-39.5) {mu}g/g. The peak thermal neutron flux as determined by post-irradiation measurements varied from 1.99 to 2.77x10{sup 9} n cm{sup -2} s{sup -1}. No serious BSH-related toxicity was observed in this series. The interim survival data in this study showed median survival times of 23.2 months for glioblastoma and 25.9 months for anaplastic astrocytoma, results which are consistent with the current conventional radiotherapy with/without boost radiation. Of the 4 residual tumors, 2 showed complete response (CR) and 2 showed partial response (PR) within 6 months following BNCT. No linear correlation was proved between the dose and the occurrence of early neurological events. The maximum boron dose of 11.7-12.2 Gy in the brain related to the occurrence of radiation necrosis. The clinical application of a mixed thermal/epithermal beam and JRR-4 facilities on BSH-based IOBNCT proved to be safe and effective in this series.
19. Four-dimensional IMRT treatment planning using a DMLC motion-tracking algorithm
Science.gov (United States)
Suh, Yelin; Sawant, Amit; Venkat, Raghu; Keall, Paul J.
2009-06-01
The purpose of this study is to develop a four-dimensional (4D) intensity-modulated radiation therapy (IMRT) treatment-planning method by modifying and applying a dynamic multileaf collimator (DMLC) motion-tracking algorithm. The 4D radiotherapy treatment scenario investigated is to obtain a 4D treatment plan based on a 4D computed tomography (CT) planning scan and to have the delivery flexible enough to account for changes in tumor position during treatment delivery. For each of 4D CT planning scans from 12 lung cancer patients, a reference phase plan was created; with its MLC leaf positions and three-dimensional (3D) tumor motion, the DMLC motion-tracking algorithm generated MLC leaf sequences for the plans of other respiratory phases. Then, a deformable dose-summed 4D plan was created by merging the leaf sequences of individual phase plans. Individual phase plans, as well as the deformable dose-summed 4D plan, are similar for each patient, indicating that this method is dosimetrically robust to the variations of fractional time spent in respiratory phases on a given 4D CT planning scan. The 4D IMRT treatment-planning method utilizing the DMLC motion-tracking algorithm explicitly accounts for 3D tumor motion and thus hysteresis and nonlinear motion, and is deliverable on a linear accelerator.
20. An interactive treatment planning system for ophthalmic plaque radiotherapy
International Nuclear Information System (INIS)
Brachytherapy using removable episcleral plaques containing sealed radioisotope sources is being studied as an alternative to enucleation in the treatment of choroidal melanoma and other tumors of the eye. Encouraging early results have been reported, but late complications which lead to loss of vision continue to be a problem. A randomized national study, the Collaborative Ocular Melanoma Study (COMS) is currently in progress to evaluate the procedure. The COMS specified isotope is 125I. Precise dosimetric calculations near the plaque may correlate strongly with complications and could also be used to optimize isotope loading patterns in the plaques. A microcomputer based treatment planning system has been developed for ophthalmic plaque brachytherapy. The program incorporates an interactive, 3-dimensional, solid-surface, color-graphic interface. The program currently supports 125I and 192Ir seeds which are treated as anisotropic line sources. Collimation effects related to plaque structure are accounted for, permitting detailed study of shielding effectiveness near the lip of a plaque. A dose distribution matrix may be calculated in any subregion of a transverse, sagittal, or coronal planar cross section of the eye, in any plane transecting the plaque and crossing the eye diametrically, or on a spherical surface within or surrounding the eye. Spherical surfaces may be displayed as 3-dimensional perspective projections or as funduscopic diagrams. Isodose contours are interpolated from the dose matrix. A pointer is also available to explicitly calculate and display dose at any location on the dosimetry surface. An interactive editing capability allows new plaque designs to be rapidly added to the system
1. A semiautomatic tool for prostate segmentation in radiotherapy treatment planning
International Nuclear Information System (INIS)
Delineation of the target volume is a time-consuming task in radiotherapy treatment planning, yet essential for a successful treatment of cancers such as prostate cancer. To facilitate the delineation procedure, the paper proposes an intuitive approach for 3D modeling of the prostate by slice-wise best fitting ellipses. The proposed estimate is initialized by the definition of a few control points in a new patient. The method is not restricted to particular image modalities but assumes a smooth shape with elliptic cross sections of the object. A training data set of 23 patients was used to calculate a prior shape model. The mean shape model was evaluated based on the manual contour of 10 test patients. The patient records of training and test data are based on axial T1-weighted 3D fast-field echo (FFE) sequences. The manual contours were considered as the reference model. Volume overlap (Vo), accuracy (Ac) (both ratio, range 0-1, optimal value 1) and Hausdorff distance (HD) (mm, optimal value 0) were calculated as evaluation parameters. The median and median absolute deviation (MAD) between manual delineation and deformed mean best fitting ellipses (MBFE) was Vo (0.9 ± 0.02), Ac (0.81 ± 0.03) and HD (4.05 ± 1.3)mm and between manual delineation and best fitting ellipses (BFE) was Vo (0.96 ± 0.01), Ac (0.92 ± 0.01) and HD (1.6 ± 0.27)mm. Additional results show a moderate improvement of the MBFE results after Monte Carlo Markov Chain (MCMC) method. The results emphasize the potential of the proposed method of modeling the prostate by best fitting ellipses. It shows the robustness and reproducibility of the model. A small sample test on 8 patients suggest possible time saving using the model
2. Planning and execution of Raft River stimulation treatments
Energy Technology Data Exchange (ETDEWEB)
Verity, R.V.; Crichlow, H.B. (ed.)
1980-02-07
The following topics are discussed for two Raft River Valley wells: well characteristics and treatment objectives, treatment selection and design, treatment history, mechanical arrangements and job costs. (MHR)
3. Deliverable navigation for multicriteria step and shoot IMRT treatment planning
Science.gov (United States)
Craft, David; Richter, Christian
2013-01-01
We consider Pareto surface based multi-criteria optimization for step and shoot IMRT planning. By analyzing two navigation algorithms, we show both theoretically and in practice that the number of plans needed to form convex combinations of plans during navigation can be kept small (much less than the theoretical maximum number needed in general, which is equal to the number of objectives for on-surface Pareto navigation). Therefore a workable approach for directly deliverable navigation in this setting is to segment the underlying Pareto surface plans and then enforce the mild restriction that only a small number of these plans are active at any time during plan navigation, thus limiting the total number of segments used in the final plan.
4. Deliverable navigation for multicriteria step and shoot IMRT treatment planning
CERN Document Server
Craft, David
2012-01-01
We consider Pareto surface based multi-criteria optimization for step and shoot IMRT planning. By analyzing two navigation algorithms, we show both theoretically and in practice that the number of plans needed to form convex combinations of plans during navigation can be kept small (much less than the theoretical maximum number needed in general, which is equal to the number of objectives for on-surface Pareto navigation). Therefore a workable approach for directly deliverable navigation in this setting is to segment the underlying Pareto surface plans and then enforce the mild restriction that only a small number of these plans are active at any time during plan navigation, thus limiting the total number of segments used in the final plan.
5. MMCTP: a radiotherapy research environment for Monte Carlo and patient-specific treatment planning
International Nuclear Information System (INIS)
Radiotherapy research lacks a flexible computational research environment for Monte Carlo (MC) and patient-specific treatment planning. The purpose of this study was to develop a flexible software package on low-cost hardware with the aim of integrating new patient-specific treatment planning with MC dose calculations suitable for large-scale prospective and retrospective treatment planning studies. We designed the software package 'McGill Monte Carlo treatment planning' (MMCTP) for the research development of MC and patient-specific treatment planning. The MMCTP design consists of a graphical user interface (GUI), which runs on a simple workstation connected through standard secure-shell protocol to a cluster for lengthy MC calculations. Treatment planning information (e.g., images, structures, beam geometry properties and dose distributions) is converted into a convenient MMCTP local file storage format designated, the McGill RT format. MMCTP features include (a) DICOMRT, RTOG and CADPlan CART format imports; (b) 2D and 3D visualization views for images, structure contours, and dose distributions; (c) contouring tools; (d) DVH analysis, and dose matrix comparison tools; (e) external beam editing; (f) MC transport calculation from beam source to patient geometry for photon and electron beams. The MC input files, which are prepared from the beam geometry properties and patient information (e.g., images and structure contours), are uploaded and run on a cluster using shell commands controlled from the MMCTP GUI. The visualization, dose matrix operation and DVH tools offer extensive options for plan analysis and comparison between MC plans and plans imported from commercial treatment planning systems. The MMCTP GUI provides a flexible research platform for the development of patient-specific MC treatment planning for photon and electron external beam radiation therapy. The impact of this tool lies in the fact that it allows for systematic, platform-independent, large
6. Orthodontics: computer-aided diagnosis and treatment planning
Science.gov (United States)
Yi, Yaxing; Li, Zhongke; Wei, Suyuan; Deng, Fanglin; Yao, Sen
2000-10-01
The purpose of this article is to introduce the outline of our newly developed computer-aided 3D dental cast analyzing system with laser scanning, and its preliminary clinical applications. The system is composed of a scanning device and a personal computer as a scanning controller and post processor. The scanning device is composed of a laser beam emitter, two sets of linear CCD cameras and a table which is rotatable by two-degree-of-freedom. The rotating is controlled precisely by a personal computer. The dental cast is projected and scanned with a laser beam. Triangulation is applied to determine the location of each point. Generation of 3D graphics of the dental cast takes approximately 40 minutes. About 170,000 sets of X,Y,Z coordinates are store for one dental cast. Besides the conventional linear and angular measurements of the dental cast, we are also able to demonstrate the size of the top surface area of each molar. The advantage of this system is that it facilitates the otherwise complicated and time- consuming mock surgery necessary for treatment planning in orthognathic surgery.
Energy Technology Data Exchange (ETDEWEB)
Nigg, D W; Hartmann Siantar, C
2002-02-19
The Idaho National Engineering and Environmental Laboratory (INEEL) has long been active in development of advanced Monte-Carlo based computational dosimetry and treatment planning methods and software for advanced radiotherapy, with a particular focus on Neutron Capture Therapy (NCT) and, to a somewhat lesser extent, Fast-Neutron Therapy. The most recent INEEL software product system of this type is known as SERA, Simulation Environment for Radiotherapy Applications. SERA is at a mature level in its life cycle, it has been licensed for research use worldwide, and it has become well established as a computational tool for research. However, along with its strengths, SERA also has some limitations in its structure and computational methodologies. More specifically, it is optimized only for neutron-based applications. Although photon transport can be computed with SERA, the simplified model that is used is designed primarily for photons produced in the neutron transport process. Thus SERA is not appropriate for applications to, for example, standard external-beam photon radiotherapy, which is by far more commonly used in the clinic than neutron based therapy.
8. Treatment planning in severe scoliosis: the role of MRI
Energy Technology Data Exchange (ETDEWEB)
Freund, M. [Dept. of Clinical Radiology, Univ. of Muenster (Germany); Dept. of Neuroradiology, Univ. of Heidelberg Medical School (Germany); Haehnel, S.; Sartor, K. [Dept. of Neuroradiology, Univ. of Heidelberg Medical School (Germany); Thomsen, M. [Dept. of Orthopaedic Surgery, University of Heidelberg, Medical School (Germany)
2001-06-01
The use of magnetic resonance imaging (MRI) in the preoperative investigation of children with idiopathic scoliosis is controversial. Syringomyelia and other intraspinal lesions may be risk factors for neurological injury during surgical correction. Our purpose was to investigate whether pathology of the neuraxis is associated with scoliosis and to detect lesions which may threaten neurological sequelae during distraction and instrumented correction. We obtained T1- and T2-weighted images of 40 children (28 girls, 12 boys), mean age 12.7 years with severe idiopathic scoliosis (Cobb angle 50-70 ) obtained in coronal, sagittal and axial planes from the posterior cranial fossa to the sacrum, and these were assessed by two neuroradiologists and an orthopaedic surgeon prior to further treatment planning. Abnormalities of the neuraxis were found in 24 patients (60 %); five (12 %) had two or more lesions. No abnormalities of the neuraxis were found in 16 patients (40 %). There were 15 patients (38 %) with intraspinal abnormalities who deteriorated clinically and nine (22 %) who showed no clinical changes. We transferred 16 patients (40 %) from the orthopaedic to the neurosurgical department for further assessment. Our results suggest that one should investigate the neuraxis with MRI before contemplating orthopaedic surgical correction of severe idiopathic scoliosis, because the findings may lead to a change of procedure. (orig.)
9. Partial differential equations-based segmentation for radiotherapy treatment planning.
Science.gov (United States)
Gibou, Frederic; Levy, Doron; Cardenas, Carlos; Liu, Pingyu; Boyer, Arthur
2005-04-01
The purpose of this study is to develop automatic algorithms for the segmentation phase of radiotherapy treatment planning. We develop new image processing techniques that are based on solving a partial diferential equation for the evolution of the curve that identifies the segmented organ. The velocity function is based on the piecewise Mumford-Shah functional. Our method incorporates information about the target organ into classical segmentation algorithms. This information, which is given in terms of a three- dimensional wireframe representation of the organ, serves as an initial guess for the segmentation algorithm. We check the performance of the new algorithm on eight data sets of three diferent organs: rectum, bladder, and kidney. The results of the automatic segmentation were compared with a manual seg- mentation of each data set by radiation oncology faculty and residents. The quality of the automatic segmentation was measured with the k-statistics", and with a count of over- and undersegmented frames, and was shown in most cases to be very close to the manual segmentation of the same data. A typical segmentation of an organ with sixty slices takes less than ten seconds on a Pentium IV laptop.
10. A dosimetric comparison of four treatment planning methods for high grade glioma
Directory of Open Access Journals (Sweden)
Miller Robert W
2009-10-01
Full Text Available Abstract Background High grade gliomas (HGG are typically treated with a combination of surgery, radiotherapy and chemotherapy. Three dimensional (3D conformal radiotherapy treatment planning is still the main stay of treatment for these patients. New treatment planning methods suggest better dose distributions and organ sparing but their clinical benefit is unclear. The purpose of the current study was to compare normal tissue sparing and tumor coverage using four different radiotherapy planning methods in patients with high grade glioma. Methods Three dimensional conformal (3D, sequential boost IMRT, integrated boost (IB IMRT and Tomotherapy (TOMO treatment plans were generated for 20 high grade glioma patients. T1 and T2 MRI abnormalities were used to define GTV and CTV with 2 and 2.5 cm margins to define PTV1 and PTV2 respectively. Results The mean dose to PTV2 but not to PTV1 was less then 95% of the prescribed dose with IB and IMRT plans. The mean doses to the optic chiasm and the ipsilateral globe were highest with 3D plans and least with IB plans. The mean dose to the contralateral globe was highest with TOMO plans. The mean of the integral dose (ID to the brain was least with the IB plan and was lower with IMRT compared to 3D plans. The TOMO plans had the least mean D10 to the normal brain but higher mean D50 and D90 compared to IB and IMRT plans. The mean D10 and D50 but not D90 were significantly lower with the IMRT plans compared to the 3D plans. Conclusion No single treatment planning method was found to be superior to all others and a personalized approach is advised for planning and treating high-grade glioma patients with radiotherapy. Integral dose did not reflect accurately the dose volume histogram (DVH of the normal brain and may not be a good indicator of delayed radiation toxicity.
11. A methodology for automatic intensity-modulated radiation treatment planning for lung cancer
Science.gov (United States)
Zhang, Xiaodong; Li, Xiaoqiang; Quan, Enzhuo M.; Pan, Xiaoning; Li, Yupeng
2011-07-01
In intensity-modulated radiotherapy (IMRT), the quality of the treatment plan, which is highly dependent upon the treatment planner's level of experience, greatly affects the potential benefits of the radiotherapy (RT). Furthermore, the planning process is complicated and requires a great deal of iteration, and is often the most time-consuming aspect of the RT process. In this paper, we describe a methodology to automate the IMRT planning process in lung cancer cases, the goal being to improve the quality and consistency of treatment planning. This methodology (1) automatically sets beam angles based on a beam angle automation algorithm, (2) judiciously designs the planning structures, which were shown to be effective for all the lung cancer cases we studied, and (3) automatically adjusts the objectives of the objective function based on a parameter automation algorithm. We compared treatment plans created in this system (mdaccAutoPlan) based on the overall methodology with plans from a clinical trial of IMRT for lung cancer run at our institution. The 'autoplans' were consistently better, or no worse, than the plans produced by experienced medical dosimetrists in terms of tumor coverage and normal tissue sparing. We conclude that the mdaccAutoPlan system can potentially improve the quality and consistency of treatment planning for lung cancer.
Energy Technology Data Exchange (ETDEWEB)
Ziegenhein, Peter
2013-07-24
This thesis investigates the feasibility of a new IMRT planning paradigm called Interactive Dose Shaping (IDS). The IDS paradigm enables the therapist to directly impose local dose features into the therapy plan. In contrast to the conventional IMRT planning approach, IDS does not employ an objective function to drive an iterative optimization procedure. In the first part of this work, the conventional IMRT plan optimization method is investigated. Concepts for a near-optimal implementation of the planning problem are provided. The second part of this work introduces the IDS concept. It is designed to overcome clinical drawbacks of the conventional method on the one hand and to provide interactive planning strategies which exploit the full potential of modern high-performance computer hardware on the other hand. The realization of the IDS concept consists of three main parts. (1)A two-step Dose Variation and Recovery (DVR) strategy which imposes localized plan features and recovers for unintentional plan modifications elsewhere. (2)A new dose calculation method (3)The design of an IDS planning framework which provides a powerful graphical user interface. It could be shown that the IDS paradigm is able to reproduce conventionally optimized therapy plans and that the IDS concepts can be realized in real-time.
13. Treatment of Solar Generation in Electric Utility Resource Planning (Presentation)
Energy Technology Data Exchange (ETDEWEB)
Cory, K.; Sterling, J.; Taylor, M.; McLaren, J.
2014-01-01
Today's utility planners have a different market and economic context than their predecessors, including planning for the growth of renewable energy. Through interviews and a questionnaire, the authors gathered information on utility supply planning and how solar is represented. Utilities were asked to provide their resource planning process details, key assumptions (e.g. whether DG is represented as supply or negative load), modeling methodology (e.g. type of risk analytics and candidate portfolio development), capacity expansion and production simulation model software, and solar project representation (project size, capacity value and integration cost adder). This presentation aims to begin the exchange of information between utilities, regulators and other stakeholders by capturing utility-provided information about: 1) how various utilities approach long-range resource planning; 2) methods and tools utilities use to conduct resource planning; and, 3) how solar technologies are considered in the resource planning process.
14. HTGR Spent Fuel Treatment Program. HTGR Spent Fuel Treatment Development Program Plan
International Nuclear Information System (INIS)
The spent fuel treatment (SFT) program plan addresses spent fuel volume reduction, packaging, storage, transportation, fuel recovery, and disposal to meet the needs of the HTGR Lead Plant and follow-on plants. In the near term, fuel refabrication will be addressed by following developments in fresh fuel fabrication and will be developed in the long term as decisions on the alternatives dictate. The formulation of this revised program plan considered the implications of the Nuclear Waste Policy Act of 1982 (NWPA) which, for the first time, established a definitive national policy for management and disposal of nuclear wastes. Although the primary intent of the program is to address technical issues, the divergence between commercial and government interests, which arises as a result of certain provisions of the NWPA, must be addressed in the economic assessment of technically feasible alternative paths in the management of spent HTGR fuel and waste. This new SFT program plan also incorporates a significant cooperative research and development program between the United States and the Federal Republic of Germany. The major objective of this international program is to reduce costs by avoiding duplicate efforts
15. 78 FR 65675 - Proposed Collection; 60-Day Comment Request; Multidisciplinary Treatment Planning (MTP) Within...
Science.gov (United States)
2013-11-01
... will gather data on sites' definitions and terms for multidisciplinary treatment planning, composition...; Multidisciplinary Treatment Planning (MTP) Within the National Cancer Institute (NCI) Community Cancer Centers... projects to be submitted to the Office of Management and Budget (OMB) for review and approval....
16. Brain tumor delineation based on CT and MR imaging. Implications for radiotherapy treatment planning
NARCIS (Netherlands)
Heesters, M A; Wijrdeman, H K; Struikmans, H; Witkamp, T; Moerland, M A
1993-01-01
This paper deals with the impact MRI may have on radiotherapy treatment planning of brain tumors. The authors analyzed differences in size and position of treatment fields as indicated by three observers (two radiotherapists and one neuroradiologist) using CT or MR based radiotherapy planning proced
17. Treatment planning in dentistry using an electronic health record: implications for undergraduate education
NARCIS (Netherlands)
O. Tokede; M. Walji; R. Ramoni; J.M. White; M. Schoonheim-Klein; N.S. Kimmes; R. Vaderhobli; P.C. Stark; V.L. Patel; E. Kalenderian
2013-01-01
Objective Treatment planning, an essential component of clinical practice, has received little attention in the dental literature and there appears to be no consistent format being followed in the teaching and development of treatment plans within dental school curricula. No investigation, to our kn
18. Clinical implications of the anisotropic analytical algorithm for IMRT treatment planning and verification
OpenAIRE
Bragg, C.M.; Wingate, K.; Conway, J.
2008-01-01
PURPOSE: To determine the implications of the use of the Anisotropic Analytical Algorithm(AAA) for the production and dosimetric verification of IMRT plans for treatments of the prostate, parotid, nasopharynx and lung. METHODS: 72 IMRT treatment plans produced using the Pencil Beam Convolution (PBC)algorithm were recalculated using the AAA and the dose distributions compared. 24 of the plans were delivered to inhomogeneous phantoms and verification measurements made using a ...
19. Functional anatomy of the prostate: Implications for treatment planning
International Nuclear Information System (INIS)
Purpose: To summarize the functional anatomy relevant to prostate cancer treatment planning. Methods and Materials: Coronal, axial, and sagittal T2 magnetic resonance imaging (MRI) and MRI angiography were fused by mutual information and registered with computed tomography (CT) scan data sets to improve definition of zonal anatomy of the prostate and critical adjacent structures. Results: The three major prostate zones (inner, outer, and anterior fibromuscular) are visible by T2 MRI imaging. The bladder, bladder neck, and internal (preprostatic) sphincter are a continuous muscular structure and clear definition of the preprostatic sphincter is difficult by MRI. Transition zone hypertrophy may efface the bladder neck and internal sphincter. The external 'lower' sphincter is clearly visible by T2 MRI with wide variations in length. The critical erectile structures are the internal pudendal artery (defined by MRI angiogram or T2 MRI), corpus cavernosum, and neurovascular bundle. The neurovascular bundle is visible along the posterior lateral surface of the prostate on CT and MRI, but its terminal branches (cavernosal nerves) are not visible and must be defined by their relationship to the urethra within the genitourinary diaphragm. Visualization of the ejaculatory ducts within the prostate is possible on sagittal MRI. The anatomy of the prostate-rectum interface is clarified by MRI, as is the potentially important distinction of rectal muscle and rectal mucosa. Conclusion: Improved understanding of functional anatomy and imaging of the prostate and critical adjacent structures will improve prostate radiation therapy by improvement of dose and toxicity correlation, limitation of dose to critical structures, and potential improvement in post therapy quality of life
20. A Monte Carlo investigation of lung brachytherapy treatment planning
International Nuclear Information System (INIS)
Iodine-125 (125I) and Caesium-131 (131Cs) brachytherapy have been used in conjunction with sublobar resection to reduce the local recurrence of stage I non-small cell lung cancer compared with resection alone. Treatment planning for this procedure is typically performed using only a seed activity nomogram or look-up table to determine seed strand spacing for the implanted mesh. Since the post-implant seed geometry is difficult to predict, the nomogram is calculated using the TG-43 formalism for seeds in a planar geometry. In this work, the EGSnrc user-code BrachyDose is used to recalculate nomograms using a variety of tissue models for 125I and 131Cs seeds. Calculated prescription doses are compared to those calculated using TG-43. Additionally, patient CT and contour data are used to generate virtual implants to study the effects that post-implant deformation and patient-specific tissue heterogeneity have on perturbing nomogram-derived dose distributions. Differences of up to 25% in calculated prescription dose are found between TG-43 and Monte Carlo calculations with the TG-43 formalism underestimating prescription doses in general. Differences between the TG-43 formalism and Monte Carlo calculated prescription doses are greater for 125I than for 131Cs seeds. Dose distributions are found to change significantly based on implant deformation and tissues surrounding implants for patient-specific virtual implants. Results suggest that accounting for seed grid deformation and the effects of non-water media, at least approximately, are likely required to reliably predict dose distributions in lung brachytherapy patients. (paper)
1. Scanned ion beam therapy for prostate carcinoma. Comparison of single plan treatment and daily plan-adapted treatment
Energy Technology Data Exchange (ETDEWEB)
Hild, Sebastian [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Department of Biophysics, Darmstadt (Germany); University Clinic Erlangen and Friedrich- Alexander-University Erlangen-Nuernberg (FAU), Department of Radiation Oncology, Erlangen (Germany); Graeff, Christian [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Department of Biophysics, Darmstadt (Germany); Rucinski, Antoni [University Clinic Heidelberg, Heidelberg Ion-Beam Therapy Center (HIT) and Department of Radiation Oncology, Heidelberg (Germany); Sapienza Universit' a di Roma, Dipartimento di Scienze di Base e Applicate per Ingegneria, Roma (Italy); INFN, Roma (Italy); Zink, Klemens [University of Applied Sciences, Institute for Medical Physics and Radiation Protection, Giessen (Germany); University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg (Germany); Habl, Gregor [University Clinic Heidelberg, Heidelberg Ion-Beam Therapy Center (HIT) and Department of Radiation Oncology, Heidelberg (Germany); Klinikum rechts der Isar, Technische Universitaet Muenchen (TUM), Department of Radiation Oncology, Munich (Germany); Durante, Marco [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Department of Biophysics, Darmstadt (Germany); Technische Universitaet Darmstadt, Faculty of Physics, Darmstadt (Germany); Herfarth, Klaus [University Clinic Heidelberg, Heidelberg Ion-Beam Therapy Center (HIT) and Department of Radiation Oncology, Heidelberg (Germany); Bert, Christoph [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Department of Biophysics, Darmstadt (Germany); University Clinic Erlangen and Friedrich- Alexander-University Erlangen-Nuernberg (FAU), Department of Radiation Oncology, Erlangen (Germany); University Hospital Erlangen, Radiation Oncology, Erlangen (Germany)
2016-02-15
Intensity-modulated particle therapy (IMPT) for tumors showing interfraction motion is a topic of current research. The purpose of this work is to compare three treatment strategies for IMPT to determine potential advantages and disadvantages of ion prostate cancer therapy. Simulations for three treatment strategies, conventional one-plan radiotherapy (ConvRT), image-guided radiotherapy (IGRT), and online adaptive radiotherapy (ART) were performed employing a dataset of 10 prostate cancer patients with six CT scans taken at one week intervals. The simulation results, using a geometric margin concept (7-2 mm) as well as patient-specific internal target volume definitions for IMPT were analyzed by target coverage and exposure of critical structures on single fraction dose distributions. All strategies led to clinically acceptable target coverage in patients exhibiting small prostate motion (mean displacement < 4 mm), but IGRT and especially ART led to significant sparing of the rectum. In 20 % of the patients, prostate motion exceeded 4 mm causing insufficient target coverage for ConvRT (V95{sub mean} = 0.86, range 0.63-0.99) and IGRT (V95{sub mean} = 0.91, range 0.68-1.00), while ART maintained acceptable target coverage. IMPT of prostate cancer demands consideration of rectal sparing and adaptive treatment replanning for patients exhibiting large prostate motion. (orig.) [German] Adaptive Therapieansaetze fuer sich interfraktionell bewegende Zielvolumina in der intensitaetsmodulierten Partikeltherapie (IMPT) befinden sich zurzeit in der Entwicklung. In dieser Arbeit werden drei Behandlungsstrategien auf moegliche Vor- und Nachteile in der IMPT des Prostatakarzinoms hin untersucht. Auf Basis eines anonymisierten Datensatzes aus 10 Patienten mit Prostatakarzinom wurden die drei Bestrahlungsstrategien, konventionelle Ein-Plan-Strahlentherapie (ConvRT), bildunterstuetzte Strahlentherapie (IGRT) und tagesaktuelle Strahlentherapie (adaptive radiotherapy,ART), simuliert
2. Treatment planning for heavy ion irradiation. Pt. 1
Energy Technology Data Exchange (ETDEWEB)
Jaekel, O. [Deutsches Krebsforschungszentrum, Heidelberg (Germany). FS Radiologische Diagnostik und Therapie; Kraemer, M. [Gesellschaft fuer Schwerionenforschung (GSI), Biophysik, Darmstadt (Germany)
1997-09-01
In this contribution we will outline briefly the GSI beam delivery system and the qualitative differences in the methods used for inverse planning arising from it. We will describe the planning package, consisting of VOXELPLAN and TRiP and show some results for first test cases. (orig./MG)
3. Boron biodistribution for BNCT in the hamster cheek pouch oral cancer model: Combined administration of BSH and BPA
Energy Technology Data Exchange (ETDEWEB)
D.W. Nigg; William Bauer; Various Others
2014-06-01
Sodium mercaptoundecahydro-closo-dodecaborate (BSH) is being investigated clinically for BNCT. We examined the biodistribution of BSH and BPA administered jointly in different proportions in the hamster cheek pouch oral cancer model. The 3 assayed protocols were non-toxic, and showed preferential tumor boron uptake versus precancerous and normal tissue and therapeutic tumor boron concentration values (70–85 ppm). All 3 protocols warrant assessment in BNCT studies to contribute to the knowledge of (BSH+BPA)-BNCT radiobiology for head and neck cancer and optimize therapeutic efficacy.
4. The role of PET/CT in radiation treatment planning for cancer patient treatment
International Nuclear Information System (INIS)
Positron emission tomography (PET) and, more recently, integrated positron emission tomography/X ray computed tomography (PET/CT) have appeared as significant diagnostic imaging systems in clinical medicine. Accurate recognition of cancers in patients by means of PET scanning with Fluorine-18-fluorodeoxyglucose (18F-FDG) has illustrated a need to determine a mode of therapy to achieve better prognoses. The clinical management of cancer patients has improved dramatically with the introduction of clinical PET. For treatment of cancer patients, on the other hand, radiation therapy (RT) plays an important role as a non-invasive therapy. It is crucial that cancers are encompassed by high dose irradiation, particularly in cases of curative RT. Irradiation should precisely target the entire tumour and aim to minimise the size of microscopic extensions of the cancer, as well as minimize radiation damage to normal tissues. A new imaging technique has therefore been sought to allow precise delineation of the cancer target to be irradiated. Clinical PET, combined with utilization of 18F-FDG, may have an important role in radiation treatment planning (RTP) in lung cancer. In addition to determining if RT is appropriate and whether therapy will be given with curative or palliative intent, 18F-FDG-PET is useful for determining therapy ports. It can be used both to limit ports to spare normal tissue and to include additional involved regions. Several studies have shown that PET has an impact on RTP in an important proportion of patients. It is to be hoped that treatment plans that include all the 18F-FDG-avid lesions or the 18F-FDG-avid portions of a complex mass will result in more effective local control with less unnecessary tissue being treated. The IAEA has placed emphasis on the issue of application of clinical PET for radiation treatment planning in various cancer patients. Two consultants meetings were held in 2006 and their results are summarized into this IAEA
5. Radiobiology of BNCT mediated by GB-10 and GB-10+BPA in experimental oral cancer
Energy Technology Data Exchange (ETDEWEB)
Trivillin, Veronica A.; Heber, Elisa M.; Itoiz, Maria E.; Nigg, David; Calzetta, Osvaldo; Blaumann, Herman; Longhino, Juan; Schwint, Amanda E. E-mail: [email protected]
2004-11-01
We previously reported biodistribution and pharmacokinetic data for GB-10 (Na{sub 2}{sup 10}B{sub 10}H{sub 10}) and the combined administration of GB-10 and boronophenylalanine (BPA) as boron delivery agents for boron neutron capture therapy (BNCT) in the hamster cheek pouch oral cancer model. The aim of the present study was to assess, for the first time, the response of hamster cheek pouch tumors, precancerous tissue and normal tissue to BNCT mediated by GB-10 and BNCT mediated by GB-10 and BPA administered jointly using the thermalized epithermal beam of the RA-6 Reactor at the Bariloche Atomic Center. GB-10 exerted 75.5% tumor control (partial+complete remission) with no damage to precancerous tissue around tumor or to normal tissue. Thus, GB-10 proved to be a therapeutically efficient boron agent in this model despite the fact that it is not taken up selectively by oral tumor tissue. GB-10 exerted a selective effect on tumor blood vessels leading to significant tumor control with a sparing effect on normal tissue. BNCT mediated by the combined administration of GB-10 and BPA resulted in a reduction in the dose to normal tissue and would thus allow for significant escalation of dose to tumor without exceeding normal tissue tolerance.
6. Multiphysics Analysis of the 2.5 MeV BNCT RFQ Accelerator
CERN Document Server
Xiaowen, Zhu; Kun, Zhu
2016-01-01
Boron Neutron Capture Therapy (BNCT), is an advanced cancer therapy that destroys the cancer tumors using the well-known Li(p,n)Be . Because of the highly selectively reaction between a boron and a neutron, BNCT is effective for rapidly spreading cancer, invasive carcinoma, such as head and neck cancer, melanoma, malignant brain tumors and so on. The PKU RFQ group proposes an RFQ based neutron source for BNCT application. The 162.5 MHz four-vane RFQ will accelerate 20-mA H+ from 35.0 keV to 2.50 MeV in CW mode, and delivers a neutron yield of 1.73*10^13 n/sec/cm^2. The thermal management will become the most important issues. The detailed multiphysics analysis of the BNCT RFQ will be studied, and the RFQ frequency shift during nominal operating condition is also predicted. The multiphysics analysis is performed by using the CST Multiphysics Model and verified with ANSYS Multiphysics.
7. BNCT dosimetry performed with a mini twin tissue-equivalent proportional counters (TEPC).
Science.gov (United States)
Moro, D; Colautti, P; Lollo, M; Esposito, J; Conte, V; De Nardo, L; Ferretti, A; Ceballos, C
2009-07-01
The BNCT radiation field is complex because different beam components are mixed, each one having different relative biological effectiveness (RBE). Microdosimetry with tissue-equivalent proportional counters (TEPC) has proven to be an ideal dosimetric technique for mixed radiation fields, because it is able both to measure the absorbed dose and to assess the radiation field relative biological effectiveness with good accuracy. An ideal detector for BNCT should contain two TEPCs, one detector loaded with, while the other one without (10)B in order to record all beam components with a unique measurement. Moreover, such a detector should be of tiny size in order to be able to measure in the intense BNCT radiation fields without significant pile-up effects. TEPCs have been shown to be pretty good dosimeters for mixed radiation fields. In this paper the first mini twin TEPC counter for BNCT is presented, as well as first measurement at the new HYTHOR thermal irradiation facility at TAPIRO nuclear reactor and comparison with related Monte Carlo calculations.
8. Treatment of Solar Generation in Electric Utility Resource Planning
Energy Technology Data Exchange (ETDEWEB)
Sterling, J.; McLaren, J.; Taylor, M.; Cory, K.
2013-10-01
Today's utility planners have a different market and economic context than their predecessors, including planning for the growth of renewable energy. State and federal support policies, solar photovoltaic (PV) price declines, and the introduction of new business models for solar PV 'ownership' are leading to increasing interest in solar technologies (especially PV); however, solar introduces myriad new variables into the utility resource planning decision. Most, but not all, utility planners have less experience analyzing solar than conventional generation as part of capacity planning, portfolio evaluation, and resource procurement decisions. To begin to build this knowledge, utility staff expressed interest in one effort: utility exchanges regarding data, methods, challenges, and solutions for incorporating solar in the planning process. Through interviews and a questionnaire, this report aims to begin this exchange of information and capture utility-provided information about: 1) how various utilities approach long-range resource planning; 2) methods and tools utilities use to conduct resource planning; and, 3) how solar technologies are considered in the resource planning process.
9. VMAT to arclet plan conversion in a treatment planning system. Feasibility and dosimetric relationship between VMAT, arclet, and stationary fields
Energy Technology Data Exchange (ETDEWEB)
Dzierma, Yvonne; Licht, Norbert; Nuesken, Frank; Ruebe, Christian; Fleckenstein, Jochen [Saarland University Medical Center, Department of Radiotherapy, Homburg/Saar (Germany); Norton, Ian [Philips Radiation Oncology Systems, Fitchburg, WI (United States)
2015-12-15
The aim of this study was to make dynamic rotation treatment with mARC available for the non-dedicated Philips Pinnacle treatment planning system by converting SmartArc plans, offering insight into the relationship between SmartArc, mARC, and stationary field irradiation. A scripting solution is presented that can be run in the Pinnacle system. This allows for the conversion of SmartArc plans into mARC format. The dose distribution of the converted mARC plan can be evaluated both in the form of a ''real'' mARC plan with arclets and - as is generally done in treatment planning systems certified for mARC planning - by approximating the arclets as stationary fields. We present the proof of principle and dosimetric comparisons. The converted plans were irradiated without problems. For the measured 3D dose distributions, on average over 90 % points agreed with the calculated dose distributions (mARC and stationary field plans) within the gamma criteria of 3 % deviation in the local dose, 3-mm distance to agreement, for all dose values above 10 % of the maximum. The agreement between the three calculated dose distributions (SmartArc with both converted plans) was above 87 % (above 92 % when comparing mARC with stationary fields). Our solution offers the possibility of mARC planning in Pinnacle. The dose comparisons furthermore prove that the dosimetric differences between SmartArc and mARC, when appropriately translated, are minor. (orig.) [German] Diese Studie praesentiert die Konversion von SmartArc-Plaenen in mARC-Format innerhalb des Philips Pinnacle Bestrahlungsplanungssystems und vergleicht SmartArc, mARC und Stehfeldbestrahlungstechniken. Innerhalb des Pinnacle-Systems wird die Konversion von SmartArc- zu mARC-Plaenen skriptbasiert durchgefuehrt. Die resultierenden Dosisverteilungen werden sowohl mit einem Plan mit Arclet-Abstrahlung als auch mit angenaeherten Stehfelder-Plaenen verglichen. Die konvertierten Plaene koennen problemlos
10. Dosimetric and Biologic Differences in Flattened and Flattening-Filter-Free Beam Treatment Plans
CERN Document Server
Yan, Yue; Bassetti, Michael; Du, Kaifang; Saenz, Daniel; Harari, Paul; Paliwal, Bhudatt R
2015-01-01
Purpose: To quantitatively compare the dosimetric and biologic differences in treatment plans from flattened and flattening-filter-free (FFF) beam for three anatomic cancer sites. Methods and Materials: Treatment plans with static intensity-modulated radiotherapy beams and volumetric modulated arc therapy beams were generated for 13 patients for both the flattened beam and the FFF beam of the TrueBeam system. Beam energies of 6 MV and 10 MV were chosen for planning. A total of 104 treatment plans were generated in 13 patients. In order to analyze the biological effectiveness of treatment plans, dose volume histograms (DVH) were utilized. Flattened and FFF beam plans are quantitatively compared. Results: In head and neck cases, for VMAT plans, dose reduction in the FFF beam plans compared to the flattened beam in left cochlea, right submandibular gland and right parotid gland reached up to 2.36 Gy, 1.21 Gy and 1.45 Gy, respectively. Similarly, for static IMRT plans, the dose reduction of the FFF beam plans com...
11. Maximizing dosimetric benefits of IMRT in the treatment of localized prostate cancer through multicriteria optimization planning
Energy Technology Data Exchange (ETDEWEB)
Wala, Jeremiah; Craft, David [Harvard Medical School, Boston, MA (United States); Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Paly, Jon [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Zietman, Anthony [Harvard Medical School, Boston, MA (United States); Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Efstathiou, Jason, E-mail: [email protected] [Harvard Medical School, Boston, MA (United States); Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States)
2013-10-01
We examine the quality of plans created using multicriteria optimization (MCO) treatment planning in intensity-modulated radiation therapy (IMRT) in treatment of localized prostate cancer. Nine random cases of patients receiving IMRT to the prostate were selected. Each case was associated with a clinically approved plan created using Corvus. The cases were replanned using MCO-based planning in RayStation. Dose-volume histogram data from both planning systems were presented to 2 radiation oncologists in a blinded evaluation, and were compared at a number of dose-volume points. Both physicians rated all 9 MCO plans as superior to the clinically approved plans (p<10{sup −5}). Target coverage was equivalent (p = 0.81). Maximum doses to the prostate and bladder and the V50 and V70 to the anterior rectum were reduced in all MCO plans (p<0.05). Treatment planning time with MCO took approximately 60 minutes per case. MCO-based planning for prostate IMRT is efficient and produces high-quality plans with good target homogeneity and sparing of the anterior rectum, bladder, and femoral heads, without sacrificing target coverage.
12. Treatment plan comparison between helical tomotherapy and MLC-based IMRT using radiobiological measures
Science.gov (United States)
Mavroidis, Panayiotis; Costa Ferreira, Brigida; Shi, Chengyu; Lind, Bengt K.; Papanikolaou, Nikos
2007-07-01
The rapid implementation of advanced treatment planning and delivery technologies for radiation therapy has brought new challenges in evaluating the most effective treatment modality. Intensity-modulated radiotherapy (IMRT) using multi-leaf collimators (MLC) and helical tomotherapy (HT) are becoming popular modes of treatment delivery and their application and effectiveness continues to be investigated. Presently, there are several treatment planning systems (TPS) that can generate and optimize IMRT plans based on user-defined objective functions for the internal target volume (ITV) and organs at risk (OAR). However, the radiobiological parameters of the different tumours and normal tissues are typically not taken into account during dose prescription and optimization of a treatment plan or during plan evaluation. The suitability of a treatment plan is typically decided based on dosimetric criteria such as dose-volume histograms (DVH), maximum, minimum, mean and standard deviation of the dose distribution. For a more comprehensive treatment plan evaluation, the biologically effective uniform dose ({\\bar{\\bar{D}}}) is applied together with the complication-free tumour control probability (P+). Its utilization is demonstrated using three clinical cases that were planned with two different forms of IMRT. In this study, three different cancer types at different anatomical sites were investigated: head and neck, lung and prostate cancers. For each cancer type, a linac MLC-based step-and-shoot IMRT plan and a HT plan were developed. The MLC-based IMRT treatment plans were developed on the Philips treatment-planning platform, using the Pinnacle 7.6 software release. For the tomotherapy HiArt plans, the dedicated tomotherapy treatment planning station was used, running version 2.1.2. By using {\\bar{\\bar{D}}} as the common prescription point of the treatment plans and plotting the tissue response probabilities versus {\\bar{\\bar{D}}} for a range of prescription doses
13. Grout Treatment Facility Land Disposal Restriction Management Plan
International Nuclear Information System (INIS)
This document establishes management plans directed to result in the land disposal of grouted wastes at the Hanford Grout Facilities in compliance with Federal, State of Washington, and Department of Energy land disposal restrictions. 9 refs., 1 fig
14. The NUKDOS software for treatment planning in molecular radiotherapy
Energy Technology Data Exchange (ETDEWEB)
Kletting, Peter; Schimmel, Sebastian [Univ. Ulm (Germany). Klinik fuer Nuklearmedizin; Haenscheid, Heribert; Fernandez, Maria; Lassmann, Michael [Univ. Wuerzburg (Germany). Klinik fuer Nuklearmedizin; Luster, Markus [Univ. Marburg (Germany). Klinik fuer Nuklearmedizin; Nosske, Dietmar [Bundesamt fuer Strahlenschutz, Fachbereich Strahlenschutz und Gesundheit, Oberschleissheim (Germany); Glatting, Gerhard [Heidelberg Univ., Medical Radiation Physics/Radiation Protection, Mannheim (Germany)
2015-07-01
The aim of this work was the development of a software tool for treatment planning prior to molecular radiotherapy, which comprises all functionality to objectively determine the activity to administer and the pertaining absorbed doses (including the corresponding error) based on a series of gamma camera images and one SPECT/CT or probe data. NUKDOS was developed in MATLAB. The workflow is based on the MIRD formalism For determination of the tissue or organ pharmacokinetics, gamma camera images as well as probe, urine, serum and blood activity data can be processed. To estimate the time-integrated activity coefficients (TIAC), sums of exponentials are fitted to the time activity data and integrated analytically. To obtain the TIAC on the voxel level, the voxel activity distribution from the quantitative 3D SPECT/CT (or PET/CT) is used for scaling and weighting the TIAC derived from the 2D organ data. The voxel S-values are automatically calculated based on the voxel-size of the image and the therapeutic nuclide ({sup 90}Y, {sup 131}I or {sup 177}Lu). The absorbed dose coefficients are computed by convolution of the voxel TIAC and the voxel S-values. The activity to administer and the pertaining absorbed doses are determined by entering the absorbed dose for the organ at risk. The overall error of the calculated absorbed doses is determined by Gaussian error propagation. NUKDOS was tested for the operation systems Windows {sup registered} 7 (64 Bit) and 8 (64 Bit). The results of each working step were compared to commercially available (SAAMII, OLINDA/EXM) and in-house (UlmDOS) software. The application of the software is demonstrated using examples form peptide receptor radionuclide therapy (PRRT) and from radioiodine therapy of benign thyroid diseases. For the example from PRRT, the calculated activity to administer differed by 4% comparing NUKDOS and the final result using UlmDos, SAAMII and OLINDA/EXM sequentially. The absorbed dose for the spleen and tumour
15. Evaluation and scoring of radiotherapy treatment plans using an artificial neural network
International Nuclear Information System (INIS)
Purpose: The objective of this work was to demonstrate the feasibility of using an artificial neural network to predict the clinical evaluation of radiotherapy treatment plans. Methods and Materials: Approximately 150 treatment plans were developed for 16 patients who received external-beam radiotherapy for soft-tissue sarcomas of the lower extremity. Plans were assigned a figure of merit by a radiation oncologist using a five-point rating scale. Plan scoring was performed by a single physician to ensure consistency in rating. Dose-volume information extracted from a training set of 511 treatment plans on 14 patients was correlated to the physician-generated figure of merit using an artificial neural network. The neural network was tested with a test set of 19 treatment plans on two patients whose plans were not used in the training of the neural net. Results: Physician scoring of treatment plans was consistent to within one point on the rating scale 88% of the time. The neural net reproduced the physician scores in the training set to within one point approximately 90% of the time. It reproduced the physician scores in the test set to within one point approximately 83% of the time. Conclusions: An artificial neural network can be trained to generate a score for a treatment plan that can be correlated to a clinically-based figure of merit. The accuracy of the neural net in scoring plans compares well with the reproducibility of the clinical scoring. The system of radiotherapy treatment plan evaluation using an artificial neural network demonstrates promise as a method for generating a clinically relevant figure of merit
16. Treatment planning for SBRT using automated field delivery: A case study
Energy Technology Data Exchange (ETDEWEB)
Ritter, Timothy A., E-mail: [email protected] [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States); Department of Radiation Oncology, Veterans Affairs Ann Arbor Health Care System, Ann Arbor, MI (United States); Owen, Dawn [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States); Department of Radiation Oncology, Veterans Affairs Ann Arbor Health Care System, Ann Arbor, MI (United States); Brooks, Cassandra M. [Department of Radiation Oncology, Veterans Affairs Ann Arbor Health Care System, Ann Arbor, MI (United States); Stenmark, Matthew H. [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States); Department of Radiation Oncology, Veterans Affairs Ann Arbor Health Care System, Ann Arbor, MI (United States)
2015-04-01
Stereotactic body radiation therapy (SBRT) treatment planning and delivery can be accomplished using a variety of techniques that achieve highly conformal dose distributions. Herein, we describe a template-based automated treatment field approach that enables rapid delivery of more than 20 coplanar fields. A case study is presented to demonstrate how modest adaptations to traditional SBRT planning can be implemented to take clinical advantage of this technology. Treatment was planned for a left-sided lung lesion adjacent to the chest wall using 25 coplanar treatment fields spaced at 11° intervals. The plan spares the contralateral lung and is in compliance with the conformality standards set forth in Radiation Therapy and Oncology Group protocol 0915, and the dose tolerances found in the report of the American Association of Physicists in Medicine Task Group 101. Using a standard template, treatment planning was accomplished in less than 20 minutes, and each 10 Gy fraction was delivered in approximately 5.4 minutes. For those centers equipped with linear accelerators capable of automated treatment field delivery, the use of more than 20 coplanar fields is a viable SBRT planning approach and yields excellent conformality and quality combined with rapid planning and treatment delivery. Although the case study discusses a laterally located lung lesion, this technique can be applied to centrally located tumors with similar results.
17. Treatment planning for SBRT using automated field delivery: A case study
International Nuclear Information System (INIS)
Stereotactic body radiation therapy (SBRT) treatment planning and delivery can be accomplished using a variety of techniques that achieve highly conformal dose distributions. Herein, we describe a template-based automated treatment field approach that enables rapid delivery of more than 20 coplanar fields. A case study is presented to demonstrate how modest adaptations to traditional SBRT planning can be implemented to take clinical advantage of this technology. Treatment was planned for a left-sided lung lesion adjacent to the chest wall using 25 coplanar treatment fields spaced at 11° intervals. The plan spares the contralateral lung and is in compliance with the conformality standards set forth in Radiation Therapy and Oncology Group protocol 0915, and the dose tolerances found in the report of the American Association of Physicists in Medicine Task Group 101. Using a standard template, treatment planning was accomplished in less than 20 minutes, and each 10 Gy fraction was delivered in approximately 5.4 minutes. For those centers equipped with linear accelerators capable of automated treatment field delivery, the use of more than 20 coplanar fields is a viable SBRT planning approach and yields excellent conformality and quality combined with rapid planning and treatment delivery. Although the case study discusses a laterally located lung lesion, this technique can be applied to centrally located tumors with similar results
18. Language Treatment and Language Planning in Canada. Part 2: The Provinces. Language Planning Newsletter, Vol. 3, No. 4.
Science.gov (United States)
McConnell, Grant
As stated in Part 1 of this discussion, Canada is a hybrid, making use of both the macro, or policy, model and the micro, or cultivation, model of language treatment. Some concrete measures are taking place in language status and corpus planning on the inter-federal-provincial level and the provincial level, particularly in Quebec. One such…
19. Correlation between radiation dose and histopathological findings in patients with gliblastoma treated with boron neutron capture therapy (BNCT)
International Nuclear Information System (INIS)
The purpose of this study was to clarify the correlation between the radiation dose and histopathological findings in patients with glioblastoma multiforme (GBM) treated with boron neutron capture therapy (BNCT). Histopathological studies were performed on specimens from 8 patients, 3 had undergone salvage surgery and 5 were autopsied. For histopathological cure of GBM at the primary site, the optimal minimal dose to the gross tumor volume (GTV) and the clinical target volume (CTV) were 68 Gy(w) and 44 Gy(w), respectively. - Highlights: • It is very important to determine the curable BNCT radiation dose on histopathological aspect in BNCT. • Of 23 patients with GBM treated with BNCT, autopsy was performed in 5, salvage surgery in 3, and histopathological study in 8. • To achieve the histopathological cure of GBM at the primary site, the optimal minimal dose to the GTV and CTV was 68 Gy(w) and 44 Gy(w), respectively
20. Boron biodistribution for BNCT in the hamster cheek pouch oral cancer model: Combined administration of BSH and BPA
International Nuclear Information System (INIS)
Sodium mercaptoundecahydro-closo-dodecaborate (BSH) is being investigated clinically for BNCT. We examined the biodistribution of BSH and BPA administered jointly in different proportions in the hamster cheek pouch oral cancer model. The 3 assayed protocols were non-toxic, and showed preferential tumor boron uptake versus precancerous and normal tissue and therapeutic tumor boron concentration values (70–85 ppm). All 3 protocols warrant assessment in BNCT studies to contribute to the knowledge of (BSH+BPA)-BNCT radiobiology for head and neck cancer and optimize therapeutic efficacy. - Highlights: • We study the biodistribution of BPA+BSH for BNCT in experimental oral cancer. • The 3 BPA+BSH protocols assayed are potentially therapeutic. • Different proportions of B compounds with different CBE factors will affect response
1. Automatic treatment planning implementation using a database of previously treated patients
Science.gov (United States)
Moore, J. A.; Evans, K.; Yang, W.; Herman, J.; McNutt, T.
2014-03-01
Purpose: Using a database of prior treated patients, it is possible to predict the dose to critical structures for future patients. Automatic treatment planning speeds the planning process by generating a good initial plan from predicted dose values. Methods: A SQL relational database of previously approved treatment plans is populated via an automated export from Pinnacle3. This script outputs dose and machine information and selected Regions of Interests as well as its associated Dose-Volume Histogram (DVH) and Overlap Volume Histograms (OVHs) with respect to the target structures. Toxicity information is exported from Mosaiq and added to the database for each patient. The SQL query is designed to ask the system for the lowest achievable dose for a specified region of interest (ROI) for each patient with a given volume of that ROI being as close or closer to the target than the current patient. Results: The additional time needed to calculate OVHs is approximately 1.5 minutes for a typical patient. Database lookup of planning objectives takes approximately 4 seconds. The combined additional time is less than that of a typical single plan optimization (2.5 mins). Conclusions: An automatic treatment planning interface has been successfully used by dosimetrists to quickly produce a number of SBRT pancreas treatment plans. The database can be used to compare dose to individual structures with the toxicity experienced and predict toxicities before planning for future patients.
2. Calculation of Absorbed Dose in Target Tissue and Equivalent Dose in Sensitive Tissues of Patients Treated by BNCT Using MCNP4C
Science.gov (United States)
Zamani, M.; Kasesaz, Y.; Khalafi, H.; Pooya, S. M. Hosseini
Boron Neutron Capture Therapy (BNCT) is used for treatment of many diseases, including brain tumors, in many medical centers. In this method, a target area (e.g., head of patient) is irradiated by some optimized and suitable neutron fields such as research nuclear reactors. Aiming at protection of healthy tissues which are located in the vicinity of irradiated tissue, and based on the ALARA principle, it is required to prevent unnecessary exposure of these vital organs. In this study, by using numerical simulation method (MCNP4C Code), the absorbed dose in target tissue and the equiavalent dose in different sensitive tissues of a patiant treated by BNCT, are calculated. For this purpose, we have used the parameters of MIRD Standard Phantom. Equiavelent dose in 11 sensitive organs, located in the vicinity of target, and total equivalent dose in whole body, have been calculated. The results show that the absorbed dose in tumor and normal tissue of brain equal to 30.35 Gy and 0.19 Gy, respectively. Also, total equivalent dose in 11 sensitive organs, other than tumor and normal tissue of brain, is equal to 14 mGy. The maximum equivalent doses in organs, other than brain and tumor, appear to the tissues of lungs and thyroid and are equal to 7.35 mSv and 3.00 mSv, respectively.
3. Manufacturing of thin films of boron for the measurement of the {sup 10}B(n, {alpha}){sup 7} Li reaction used in BNCT
Energy Technology Data Exchange (ETDEWEB)
Smilgys, Barbara; Oliveira, Sandro Guedes de; Hadler Neto, Julio Cesar; Vellame, Igor Alencar [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin; Soares, Cleber Jose; Salim, Leonardo Alfredo [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas; Coelho, Paulo Rogerio Pinto [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear
2011-07-01
Full text: The Boron Neutron Capture Therapy (BNCT) is considered to be a possible treatment for different types of aggressive cancers located in areas of difficult access or which already have metastasis. The working principle of this therapy is the selective delivery of a greater amount of boron to the tumor cells than to the healthy ones, followed by the neutron irradiation that will induce the emission of {alpha} particles through the {sup 10}B(n, {alpha}){sup 7} Li reaction used in BNCT reaction. The high energy deposition of the product particles causes the death of the cells and this therapy becomes much effective if the healthy tissue is less exposed to this radiation. The objective of this work is to develop a method for measuring the rate of this reaction by using thin films of boron. We have manufactured thin films with different concentrations of boron deposited on mica and the thin films were exposed to different irradiation time intervals at the reactor IEA-R1 located at IPEN, Sao Paulo. Here we show our first results on the density and uniformity of the thin films, where the detection of the particles is made using plastic track detectors (CR-39) which have their structures damaged by the passage of ions. (author)
4. A FORTRAN program for the optimization of radiotherapy treatment planning using the complication probability factor (CPF).
Science.gov (United States)
Wolbarst, A B; Sternick, E S; Curran, B H; Kosinski, R J; Dritschilo, A
1980-04-01
The complication probability factor (CPF) is an objective function, based directly on radiobiological principles and clinical data, for the optimization of radiotherapy treatment planning; it measures the likelihood that a given radiation dose distribution will lead to serious complications in the patient as a result of damage to healthy tissue. A computerized search can be made for that treatment plan which delivers an acceptable tumoricidal dose, yet minimizes the CPF as averaged over the total volume of healthy tissue irradiated. The CPF FORTRAN program, run on a PDP 11/55 in conjunction with a commercially available radiotherapy treatment planning package, is described in detail.
5. Concept for individualized patient allocation: ReCompare—remote comparison of particle and photon treatment plans
International Nuclear Information System (INIS)
Identifying those patients who have a higher chance to be cured with fewer side effects by particle beam therapy than by state-of-the-art photon therapy is essential to guarantee a fair and sufficient access to specialized radiotherapy. The individualized identification requires initiatives by particle as well as non-particle radiotherapy centers to form networks, to establish procedures for the decision process, and to implement means for the remote exchange of relevant patient information. In this work, we want to contribute a practical concept that addresses these requirements. We proposed a concept for individualized patient allocation to photon or particle beam therapy at a non-particle radiotherapy institution that bases on remote treatment plan comparison. We translated this concept into the web-based software tool ReCompare (REmote COMparison of PARticlE and photon treatment plans). We substantiated the feasibility of the proposed concept by demonstrating remote exchange of treatment plans between radiotherapy institutions and the direct comparison of photon and particle treatment plans in photon treatment planning systems. ReCompare worked with several tested standard treatment planning systems, ensured patient data protection, and integrated in the clinical workflow. Our concept supports non-particle radiotherapy institutions with the patient-specific treatment decision on the optimal irradiation modality by providing expertise from a particle therapy center. The software tool ReCompare may help to improve and standardize this personalized treatment decision. It will be available from our website when proton therapy is operational at our facility
6. A medical expert system approach using artificial neural networks for standardized treatment planning
International Nuclear Information System (INIS)
Purpose: Many radiotherapy treatment plans involve some level of standardization (e.g., in terms of beam ballistics, collimator settings, and wedge angles), which is determined primarily by tumor site and stage. If patient-to-patient variations in the size and shape of relevant anatomical structures for a given treatment site are adequately sampled, then it would seem possible to develop a general method for automatically mapping individual patient anatomy to a corresponding set of treatment variables. A medical expert system approach to standardized treatment planning was developed that should lead to improved planning efficiency and consistency. Methods and Materials: The expert system was designed to specify treatment variables for new patients based upon a set of templates (a database of treatment plans for previous patients) and a similarity metric for determining the goodness of fit between the relevant anatomy of new patients and patients in the database. A set of artificial neural networks was used to optimize the treatment variables to the individual patient. A simplified example, a four-field box technique for prostate treatments based upon a single external contour, was used to test the viability of the approach. Results: For a group of new prostate patients, treatment variables specified by the expert system were compared to treatment variables chosen by the dosimetrists. Performance criteria included dose uniformity within the target region and dose to surrounding critical organs. For this standardized prostate technique, a database consisting of approximately 75 patient records was required for the expert system performance to approach that of the dosimetrists. Conclusions: An expert system approach to standardized treatment planning has the potential of improving the overall efficiency of the planning process by reducing the number of iterations required to generate an optimized dose distribution, and to function most effectively, should be closely
7. Challenges of radiotherapy: Report on the 4D treatment planning workshop 2013
NARCIS (Netherlands)
Knopf, Antje; Nill, Simeon; Yohannes, Indra; Graeff, Christian; Dowdell, Stephen; Kurz, Christopher; Sonke, Jan-Jakob; Biegun, Aleksandra K.; Lang, Stephanie; McCelland, Jamie; Champion, Benjamin; Fast, Martin; Wölfelschneider, Jens; Gianoli, Chiara; Rucinscki, Antoni; Baroni, Guido; Richter, Christian; van de Water, Steven; Grassberger, Clemens; Weber, Damien; Poulsen, Per; Shimizu, Shinichi; Bert, Christoph
2014-01-01
This report, compiled by experts on the treatment of mobile targets with advanced radiotherapy, summarizes the main conclusions and innovations achieved during the 4D treatment planning workshop 2013. This annual workshop focuses on research aiming to advance 4D radiotherapy treatments, including al
8. Substituted plan analysis in the environmental impact assessment of Yongchuan wastewater treatment project
Institute of Scientific and Technical Information of China (English)
FANG Jun-hua
2006-01-01
Substituted plan in the environmental impact assessment (EIA) mainly means the treatment technology and the substituted site of plant, and it also includes the many kinds of environment protection measures. This paper will make detailed analysis on the treatment technology, the substituted site of plant, the purpose of discharged water and the dispose of sludge in the Yongchuan wastewater treatment project.
9. Federal Facility Compliance Act: Conceptual Site Treatment Plan for Lawrence Livermore National Laboratory, Livermore, California
International Nuclear Information System (INIS)
The Department of Energy (DOE) is required by section 3021(b) of the Resource Conservation and Recovery Act (RCRA), as amended by the Federal Facility Compliance Act (the Act), to prepare plans describing the development of treatment capacities and technologies for treating mixed waste. The Act requires site treatment plans (STPs or plans) to be developed for each site at which DOE generates or stores mixed waste and submitted to the State or EPA for approval, approval with modification, or disapproval. The Lawrence Livermore National Laboratory (LLNL) Conceptual Site Treatment Plan (CSTP) is the preliminary version of the plan required by the Act and is being provided to California, the US Environmental Protection Agency (EPA), and others for review. A list of the other DOE sites preparing CSTPs is included in Appendix 1.1 of this document. Please note that Appendix 1.1 appears as Appendix A, pages A-1 and A-2 in this document
10. Federal Facility Compliance Act: Conceptual Site Treatment Plan for Lawrence Livermore National Laboratory, Livermore, California
Energy Technology Data Exchange (ETDEWEB)
1993-10-01
The Department of Energy (DOE) is required by section 3021(b) of the Resource Conservation and Recovery Act (RCRA), as amended by the Federal Facility Compliance Act (the Act), to prepare plans describing the development of treatment capacities and technologies for treating mixed waste. The Act requires site treatment plans (STPs or plans) to be developed for each site at which DOE generates or stores mixed waste and submitted to the State or EPA for approval, approval with modification, or disapproval. The Lawrence Livermore National Laboratory (LLNL) Conceptual Site Treatment Plan (CSTP) is the preliminary version of the plan required by the Act and is being provided to California, the US Environmental Protection Agency (EPA), and others for review. A list of the other DOE sites preparing CSTPs is included in Appendix 1.1 of this document. Please note that Appendix 1.1 appears as Appendix A, pages A-1 and A-2 in this document.
11. Waste Treatment Technology Process Development Plan For Hanford Waste Treatment Plant Low Activity Waste Recycle
Energy Technology Data Exchange (ETDEWEB)
McCabe, Daniel J.; Wilmarth, William R.; Nash, Charles A.
2013-08-29
The purpose of this Process Development Plan is to summarize the objectives and plans for the technology development activities for an alternative path for disposition of the recycle stream that will be generated in the Hanford Waste Treatment Plant Low Activity Waste (LAW) vitrification facility (LAW Recycle). This plan covers the first phase of the development activities. The baseline plan for disposition of this stream is to recycle it to the WTP Pretreatment Facility, where it will be concentrated by evaporation and returned to the LAW vitrification facility. Because this stream contains components that are volatile at melter temperatures and are also problematic for the glass waste form, they accumulate in the Recycle stream, exacerbating their impact on the number of LAW glass containers. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to acceptable concentrations in the LAW glass, and reducing the halides in the Recycle is a key component of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, this stream does not have a proven disposition path, and resolving this gap becomes vitally important. This task seeks to examine the impact of potential future disposition of this stream in the Hanford tank farms, and to develop a process that will remove radionuclides from this stream and allow its diversion to another disposition path, greatly decreasing the LAW vitrification mission duration and quantity of glass waste. The origin of this LAW Recycle stream will be from the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP) from the LAW melter off-gas system. The stream is expected to be a dilute salt solution with near neutral pH, and will likely contain some insoluble solids from melter carryover or precipitates of scrubbed components (e.g. carbonates). The soluble
12. IMRT treatment planning based on prioritizing prescription goals.
Science.gov (United States)
Wilkens, Jan J; Alaly, James R; Zakarian, Konstantin; Thorstad, Wade L; Deasy, Joseph O
2007-03-21
Determining the 'best' optimization parameters in IMRT planning is typically a time-consuming trial-and-error process with no unambiguous termination point. Recently we and others proposed a goal-programming approach which better captures the desired prioritization of dosimetric goals. Here, individual prescription goals are addressed stepwise in their order of priority. In the first step, only the highest order goals are considered (target coverage and dose-limiting normal structures). In subsequent steps, the achievements of the previous steps are turned into hard constraints and lower priority goals are optimized, in turn, subject to higher priority constraints. So-called 'slip' factors were introduced to allow for slight, clinically acceptable violations of the constraints. Focusing on head and neck cases, we present several examples for this planning technique. The main advantages of the new optimization method are (i) its ability to generate plans that meet the clinical goals, as well as possible, without tuning any weighting factors or dose-volume constraints, and (ii) the ability to conveniently include more terms such as fluence map smoothness. Lower level goals can be optimized to the achievable limit without compromising higher order goals. The prioritized prescription-goal planning method allows for a more intuitive and human-time-efficient way of dealing with conflicting goals compared to the conventional trial-and-error method of varying weighting factors and dose-volume constraints.
13. ET-14OPTIMISATION OF BORONOPHENYLALANINE (BPA) DELIVERY AND LAT1 EXPRESSION FOR THE CLINICAL APPLICATION OF BORON NEUTRON CAPTURE THERAPY (BNCT) IN GLIOBLASTOMA
Science.gov (United States)
Cruickshank, Garth; Detta, Allah; Green, Stuart; Lockyer, Nick; Ngoga, Desire; Ghani, Zahir; Phoenix, Ben
2014-01-01
BNCT is a biologically targeted radiotherapy where preferential boron uptake interacts with a neutron beam in cancerous cells causing irreparable alpha DNA damage. This requires the delivery of at least 30 parts per million (ppm) of 10B into tumour tissue and 30ppm boron) indicates potential BNCT targeting after surgery. Tumour boron uptake is governed by LAT-1 behaviour rather than BBB penetration and explains previous variable clinical results, whilst supporting the LAT1 determined selection of patients for BNCT
14. Optimization in radiotherapy treatment planning thanks to a fast dose calculation method
International Nuclear Information System (INIS)
This thesis deals with the radiotherapy treatments planning issue which need a fast and reliable treatment planning system (TPS). The TPS is composed of a dose calculation algorithm and an optimization method. The objective is to design a plan to deliver the dose to the tumor while preserving the surrounding healthy and sensitive tissues. The treatment planning aims to determine the best suited radiation parameters for each patient's treatment. In this thesis, the parameters of treatment with IMRT (Intensity modulated radiation therapy) are the beam angle and the beam intensity. The objective function is multi-criteria with linear constraints. The main objective of this thesis is to demonstrate the feasibility of a treatment planning optimization method based on a fast dose-calculation technique developed by (Blanpain, 2009). This technique proposes to compute the dose by segmenting the patient's phantom into homogeneous meshes. The dose computation is divided into two steps. The first step impacts the meshes: projections and weights are set according to physical and geometrical criteria. The second step impacts the voxels: the dose is computed by evaluating the functions previously associated to their mesh. A reformulation of this technique makes possible to solve the optimization problem by the gradient descent algorithm. The main advantage of this method is that the beam angle parameters could be optimized continuously in 3 dimensions. The obtained results in this thesis offer many opportunities in the field of radiotherapy treatment planning optimization. (author)
15. Automated VMAT treatment planning for stage III lung cancer: how does it compare with IMRT?
Science.gov (United States)
Quan, Enzhuo M.; Chang, Joe Y.; Liao, Zhongxing; Xia, Tingyi; Yuan, Zhiyong; Liu, Hui; Li, Xiaoqiang; Wages, Cody A.; Mohan, Radhe; Zhang, Xiaodong
2012-01-01
Purpose To compare the quality of volumetric modulated arc therapy (VMAT) or intensity-modulated radiation therapy (IMRT) plans generated by an automated inverse planning system with that of dosimetrist-generated IMRT treatment plans for patients with stage III lung cancer. Methods and Materials Two groups of eight patients with stage III lung cancer were randomly selected. For group I, the dosimetrists spent their best effort in designing IMRT plans to compete with the automated inverse planning system (mdaccAutoPlan); for group II, the dosimetrists were not in competition and spent their regular effort. Five experienced radiation oncologists independently blind-reviewed and ranked the three plans for each patient, a rank of “1” being the best and “3” the worst. Dosimetric measures were also performed to quantitatively evaluate the three types of plans. Results Blind rankings from different oncologists were generally consistent. For group I, the auto-VMAT, auto-IMRT, and manual-IMRT plans received average ranks of 1.6, 2.13, and 2.18, respectively. The auto-VMAT plans in group I had 10% higher PTV conformality and 24% lower esophagus V70 than the manual-IMRT plans; they also resulted in over 20% higher complication-free tumor control probability (p+) than either type of IMRT plans. The auto- and manual-IMRT plans in this group yielded generally comparable dosimetric measures. For group II, the auto-VMAT, auto-IMRT, and manual-IMRT plans received average ranks of 1.55, 1.75, and 2.75, respectively. Compared to the manual-IMRT plans in this group, the auto-VMAT plans and the auto-IMRT plans showed, respectively, 17% and 14% higher PTV dose conformality, 8% and 17% lower mean lung dose, 17% and 26% lower mean heart dose, and 36% and 23% higher p+. Conclusions mdaccAutoPlan is capable of generating high-quality VMAT and IMRT treatment plans for stage III lung cancer. Manual-IMRT plans could achieve quality similar to auto-IMRT plans if best effort were spent
16. Deliverable navigation for multicriteria IMRT treatment planning by combining shared and individual apertures
Science.gov (United States)
Fredriksson, Albin; Bokrantz, Rasmus
2013-11-01
We consider the problem of deliverable Pareto surface navigation for step-and-shoot intensity-modulated radiation therapy. This problem amounts to calculation of a collection of treatment plans with the property that convex combinations of plans are directly deliverable. Previous methods for deliverable navigation impose restrictions on the number of apertures of the individual plans, or require that all treatment plans have identical apertures. We introduce simultaneous direct step-and-shoot optimization of multiple plans subject to constraints that some of the apertures must be identical across all plans. This method generalizes previous methods for deliverable navigation to allow for treatment plans with some apertures from a collective pool and some apertures that are individual. The method can also be used as a post-processing step to previous methods for deliverable navigation in order to improve upon their plans. By applying the method to subsets of plans in the collection representing the Pareto set, we show how it can enable convergence toward the unrestricted (non-navigable) Pareto set where all apertures are individual.
17. A Simulation Study of Automated Treatment Planning in a Mental Hospital
OpenAIRE
Craig, T. J.; Richardson, M. A.; Pass, R.; Simpson, F.; Summers, I.
1983-01-01
A simulation study of automated treatment planning in a state mental hospital revealed that automation, per se, was of little direct benefit to clinicians and had virtually no impact on the clinical process. However, supervisory and quality assurance staff found considerable utility in the ability to generate reports previously unavailable. The implications for planning automated clinical systems are discussed.
18. Automated generation of IMRT treatment plans for prostate cancer patients with metal hip prostheses: Comparison of different planning strategies
Energy Technology Data Exchange (ETDEWEB)
Voet, Peter W. J.; Dirkx, Maarten L. P.; Breedveld, Sebastiaan; Heijmen, Ben J. M. [Erasmus MC - Daniel den Hoed Cancer Center, Department of Radiation Oncology, Groene Hilledijk 301, 3075EA Rotterdam (Netherlands)
2013-07-15
OAR sparing. Noncoplanar beam arrangements and, to a larger extent, increasing the number of treatment beams further improved plan quality.
19. SU-E-T-527: Prior Knowledge Guided TomoTherapy Treatment Planning
Energy Technology Data Exchange (ETDEWEB)
Lian, J [UniversityNorth Carolina, Chapel Hill, NC (United States); Yuan, L; Wu, Q [Duke University Medical Center, Durham, NC (United States); Zhu, X [Univ. of North Carolina at Chapel Hill, Chapel Hill, NC (United States); Chera, B [University of North Carolina, Chapel Hill, NC (United States); Chang, S [UNC School of Medicine, Chapel Hill, NC (United States)
2014-06-01
Purpose: The quality and efficiency of radiotherapy treatment planning are highly planer dependent. Previously we have developed a statistical model to correlate anatomical features with dosimetry features of head and neck Tomotherapy treatment. The model enables us to predict the best achievable dosimetry for individual patient prior to treatment planning. The purpose of this work is to study if the prediction model can facilitate the treatment planning in both the efficiency and dosimetric quality. Methods: The anatomy-dosimetry correlation model was used to calculate the expected DVH for nine patients formerly treated. In Group A (3 patients), the model prediction agreed with the clinic plan; in Group B (3 patients), the model predicted lower larynx mean dose than the clinic plan; in Group C (3 patients), the model suggested the brainstem could be further spared. Guided by the prior knowledge, we re-planned all 9 cases. The number of interactions during the optimization process and dosimetric endpoints between the original clinical plan and model-guided re-plan were compared. Results: For Group A, the difference of target coverage and organs-at-risk sparing is insignificant (p>0.05) between the replan and the clinical plan. For Group B, the clinical plan larynx median dose is 49.4±4.7 Gy, while the prediction suggesting 40.0±6.2 Gy (p<0.05). The re-plan achieved 41.5±6.6 Gy, with similar dose on other structures as clinical plan. For Group C, the clinical plan brainstem maximum dose is 44.7±5.5 Gy. The model predicted lower value 32.2±3.8 Gy (p<0.05). The re-plans reduced brainstem maximum dose to 31.8±4.1 Gy without affecting the dosimetry of other structures. In the replanning of the 9 cases, the times operator interacted with TPS are reduced on average about 50% compared to the clinical plan. Conclusion: We have demonstrated that the prior expert knowledge embedded model improved the efficiency and quality of Tomotherapy treatment planning.
20. Computed tomography imaging parameters for inhomogeneity correction in radiation treatment planning
OpenAIRE
Das, Indra J; Chee-Wai Cheng; Minsong Cao; Johnstone, Peter A. S.
2016-01-01
Modern treatment planning systems provide accurate dosimetry in heterogeneous media (such as a patient' body) with the help of tissue characterization based on computed tomography (CT) number. However, CT number depends on the type of scanner, tube voltage, field of view (FOV), reconstruction algorithm including artifact reduction and processing filters. The impact of these parameters on CT to electron density (ED) conversion had been subject of investigation for treatment planning in various...
1. Development of a computed tomographic scanner for radiation therapy treatment planning.
Science.gov (United States)
Smith, V; Parker, D L; Stanley, J H; Phillips, T L; Boyd, D P; Kan, P T
1980-08-01
The authors describe a low-cost CT scanner integrated with a radiotherapy simulator and designed for treatment planning. The standard rotational gantry and x-ray tube of the simulator are used with a multiwire xenon lonization chamber and simple current-proportional readout system to measure patient attenuation, avoiding problems associated with diagnostic CT scanners in treatment planning. Although design constraints limit performance, software compensation techniques have reduced artifacts and given satisfactory images.
2. Coverage-based treatment planning: Optimizing the IMRT PTV to meet a CTV coverage criterion
OpenAIRE
Gordon, J. J.; Siebers, J. V.
2009-01-01
This work demonstrates an iterative approach—referred to as coverage-based treatment planning—designed to produce treatment plans that ensure target coverage for a specified percentage of setup errors. In this approach the clinical target volume to planning target volume (CTV-to-PTV) margin is iteratively adjusted until the specified CTV coverage is achieved. The advantage of this approach is that it automatically compensates for the dosimetric margin around the CTV, i.e., the extra margin th...
3. A self management plan in the treatment of adult asthma.
OpenAIRE
Beasley, R; Cushley, M; Holgate, S T
1989-01-01
To determine whether routine assessment of peak expiratory flow (PEF) in association with a self management plan based on inhaled corticosteroid use is effective in the management of chronic asthma, 36 consecutive adult patients with asthma attending an outpatient chest clinic were admitted to an open prospective study. Patients were treated with inhaled salbutamol and beclomethasone dipropionate in an attempt to achieve normal lung function. Each patient had a "potential normal value," which...
4. Clinical Realization of Sector Beam Intensity Modulation for Gamma Knife Radiosurgery: A Pilot Treatment Planning Study
Energy Technology Data Exchange (ETDEWEB)
Ma, Lijun, E-mail: [email protected] [Department of Radiation Oncology, University of California, San Francisco, California (United States); Mason, Erica; Sneed, Penny K.; McDermott, Michael; Polishchuk, Alexei; Larson, David A. [Department of Radiation Oncology, University of California, San Francisco, California (United States); Sahgal, Arjun [Department of Radiation Oncology, Sunnybrook Odette Cancer Center, University of Toronto, Toronto, Ontario (Canada)
2015-03-01
Purpose: To demonstrate the clinical feasibility and potential benefits of sector beam intensity modulation (SBIM) specific to Gamma Knife stereotactic radiosurgery (GKSRS). Methods and Materials: SBIM is based on modulating the confocal beam intensities from individual sectors surrounding an isocenter in a nearly 2π geometry. This is in contrast to conventional GKSRS delivery, in which the beam intensities from each sector are restricted to be either 0% or 100% and must be identical for any given isocenter. We developed a SBIM solution based on available clinical planning tools, and we tested it on a cohort of 12 clinical cases as a proof of concept study. The SBIM treatment plans were compared with the original clinically delivered treatment plans to determine dosimetric differences. The goal was to investigate whether SBIM would improve the dose conformity for these treatment plans without prohibitively lengthening the treatment time. Results: A SBIM technique was developed. On average, SBIM improved the Paddick conformity index (PCI) versus the clinically delivered plans (clinical plan PCI = 0.68 ± 0.11 vs SBIM plan PCI = 0.74 ± 0.10, P=.002; 2-tailed paired t test). The SBIM plans also resulted in nearly identical target volume coverage (mean, 97 ± 2%), total beam-on times (clinical plan 58.4 ± 38.9 minutes vs SBIM 63.5 ± 44.7 minutes, P=.057), and gradient indices (clinical plan 3.03 ± 0.27 vs SBIM 3.06 ± 0.29, P=.44) versus the original clinical plans. Conclusion: The SBIM method is clinically feasible with potential dosimetric gains when compared with conventional GKSRS.
5. Role of nutrition planning in the treatment for obesity.
Science.gov (United States)
Atkinson, R L
1996-12-01
The most sensible eating plans are those that involve a wide selection of foods with a modest percentage of kilocalories as fat. The dietary pyramid developed by the US Government is an excellent basis for the construction of an eating plan for life. Patients should be encouraged to develop healthy eating habits that they can maintain indefinitely, as the early inevitable consequence of finishing a diet is regain of any weight that has been lost when the patient goes back to their old eating habits. The unfortunate fact is that individuals with the disease of obesity must behave differently than those who do not. This usually means that obese persons must eat differently than lean persons, and they must do this for their entire lives. Food is a critical part of the social fabric of our society. The physician, usually in combination with a knowledgeable and empathetic dietitian or other nutritional education resource, can help obese patients choose the series of compromises in eating plans and activity levels that can be maintained for life but still allow a reasonable quality of life.
6. Role of nutrition planning in the treatment for obesity.
Science.gov (United States)
Atkinson, R L
1996-12-01
The most sensible eating plans are those that involve a wide selection of foods with a modest percentage of kilocalories as fat. The dietary pyramid developed by the US Government is an excellent basis for the construction of an eating plan for life. Patients should be encouraged to develop healthy eating habits that they can maintain indefinitely, as the early inevitable consequence of finishing a diet is regain of any weight that has been lost when the patient goes back to their old eating habits. The unfortunate fact is that individuals with the disease of obesity must behave differently than those who do not. This usually means that obese persons must eat differently than lean persons, and they must do this for their entire lives. Food is a critical part of the social fabric of our society. The physician, usually in combination with a knowledgeable and empathetic dietitian or other nutritional education resource, can help obese patients choose the series of compromises in eating plans and activity levels that can be maintained for life but still allow a reasonable quality of life. PMID:8977055
7. Optimization of tomotherapy treatment planning for patients with bilateral hip prostheses
OpenAIRE
Chapman, David; Smith, Shaun; Barnett, Rob; Bauman, Glenn; Yartsev, Slav
2014-01-01
Background To determine the effect of different imaging options and the most efficient imaging strategy for treatment planning of patients with hip prostheses. Methods The planning kilovoltage CT (kVCT) and daily megavoltage CT (MVCT) studies for three prostate cancer patients with bilateral hip prostheses were used for creating hybrid kVCT/MVCT image sets. Treatment plans were created for kVCT images alone, hybrid kVCT/MVCT images, and MVCT images alone using the same dose prescription and p...
8. Re-envisioning Addiction Treatment: A Six-Point Plan.
Science.gov (United States)
Kellogg, Scott H; Tatarsky, Andrew
2012-01-01
This article is focused on improving the quality of addiction treatment. Based on observations that patients are leaving treatment too early and/or are continuing to use substances during their care, the authors propose six actions that could help reorient and revitalize this kind of clinical work: (1) conceptualize and treat addictive disorders within a psychiatric/mental health framework; (2) make the creation of a strong therapeutic alliance a core part of the healing process; (3) understand patients' addictions and other problems using models based on multiple internal parts, voices, or modes; (4) make contingency management and the use of positive reinforcement systems a standard and central practice in all treatment settings; (5) envision long-term change and healing through the lens of identity theory; and (6) integrate the growing developments in recovery culture with formal treatment. PMID:22754086
9. Evaluation of isocenter reproducibility in telemedicine of 3D-radiotherapy treatment planning
Energy Technology Data Exchange (ETDEWEB)
Hirota, Saeko; Tsujino, Kayoko; Kimura, Kouji; Takada, Yoshiki; Hishikawa, Yoshio; Kono, Michio [Hyogo Medical Center for Adults, Akashi (Japan); Soejima, Toshinori; Kodama, Akihisa
2000-09-01
To evaluate the utility in telemedicine of Three-Dimensional Radiotherapy Treatment Planning (tele-3D-RTP) and to examine the accuracy of isocenter reproducibility in its offline trial. CT data of phantoms and patients in the satellite hospital were transferred to our hospital via floppy-disk and 3D-radiotherapy plans were generated by 3D-RTP computer in our hospital. Profile data of CT and treatment beams in the satellite hospital were pre-installed into the computer. Tele-3D-RTPs were performed in 3 phantom plans and 14 clinical plans for 13 patients. Planned isocenters were well reproduced, especially in the immobilized head and neck/brain tumor cases, whose 3D-vector of aberration was 1.96{+-}1.38 (SD) mm. This teletherapy system is well applicable for practical use and can provides cost-reduction through sharing the resources of expensive equipment and radiation oncologists. (author)
10. A Multi-Criteria Framework with Voxel-Dependent Parameters for Radiotherapy Treatment Plan Optimization
CERN Document Server
Zarepisheh, Masoud; Li, Nan; Jia, Xun; Jiang, Steve B
2012-01-01
In a treatment plan optimization problem for radiotherapy, a clinically acceptable plan is usually generated by an optimization process with weighting factors or reference doses adjusted for organs. Recent discoveries indicate that adjusting parameters associated with each voxel may lead to better plan quality. However, it is still unclear regarding the mathematical reasons behind it. To answer questions related to this problem, we establish in this work a new mathematical framework equipped with two theorems. The new framework clarifies the different consequences of adjusting organ-dependent and voxel-dependent parameters for the treatment plan optimization of radiation therapy, as well as the different effects of adjusting weighting factors versus reference doses in the optimization process. The main discoveries are threefold: 1) While in the organ-based model the selection of the objective function has an impact on the quality of the optimized plans, this is no longer an issue for the voxel-based model sin...
11. Prior-knowledge treatment planning for volumetric arc therapy using feature-based database mining.
Science.gov (United States)
Schreibmann, Eduard; Fox, Tim
2014-03-06
Treatment planning for volumetric arc therapy (VMAT) is a lengthy process that requires many rounds of optimizations to obtain the best treatment settings and optimization constraints for a given patient's geometry. We propose a feature-selection search engine that explores previously treated cases of similar anatomy, returning the optimal plan configurations and attainable DVH constraints. Using an institutional database of 83 previously treated cases of prostate carcinoma treated with volumetric-modulated arc therapy, the search procedure first finds the optimal isocenter position with an optimization procedure, then ranks the anatomical similarity as the mean distance between targets. For the best matching plan, the planning information is reformatted to the DICOM format and imported into the treatment planning system to suggest isocenter, arc directions, MLC patterns, and optimization constraints that can be used as starting points in the optimization process. The approach was tested to create prospective treatment plans based on anatomical features that match previously treated cases from the institution database. By starting from a near-optimal solution and using previous optimization constraints, the best matching test only required simple optimization steps to further decrease target inhomogeneity, ultimately reducing time spend by the therapist in planning arcs' directions and lengths.
12. Stereotactic Arrhythmia Radioablation (STAR) of Ventricular Tachycardia: A Treatment Planning Study
Science.gov (United States)
Fahimian, Benjamin; Soltys, Scott G; Zei, Paul; Lo, Anthony; Gardner, Edward A; Maguire, Patrick J; Loo Jr., Billy W
2016-01-01
Purpose The first stereotactic arrhythmia radioablation (STAR) of ventricular tachycardia (VT) was delivered at Stanford on a robotic radiosurgery system (CyberKnife® G4) in 2012. The results warranted further investigation of this treatment. Here we compare dosimetrically three possible treatment delivery platforms for STAR. Methods The anatomy and target volume of the first treated patient were used for this study. A dose of 25 Gy in one fraction was prescribed to the planning target volume (PTV). Treatment plans were created on three treatment platforms: CyberKnife® G4 system with Iris collimator (Multiplan, V. 4.6)(Plan #1), CyberKnife® M6 system with InCise 2TM multileaf collimator (Multiplan V. 5.3)(Plan #2) and Varian TrueBeamTM STx with HD 120TM MLC and 10MV flattening filter free (FFF) beam (Eclipse planning system, V.11) (Plan #3 coplanar and #4 noncoplanar VMAT plans). The four plans were compared by prescription isodose line, plan conformity index, dose gradient, as well as dose to the nearby critical structures. To assess the delivery efficiency, planned monitor units (MU) and estimated treatment time were evaluated. Results Plans #1-4 delivered 25 Gy to the PTV to the 75.0%, 83.0%, 84.3%, and 84.9% isodose lines and with conformity indices of 1.19, 1.16, 1.05, and 1.05, respectively. The dose gradients for plans #1-4 were 3.62, 3.42, 3.93, and 3.73 with the CyberKnife® MLC plan (Plan #2) the best, and the TrueBeamTM STx co-planar plan (Plan #3) the worst. The dose to nearby critical structures (lung, stomach, bowel, and esophagus) were all well within tolerance. The MUs for plans #1-4 were 27671, 16522, 6275, and 6004 for an estimated total-treatment-time/beam-delivery-time of 99/69, 65/35, 37/7, and 56/6 minutes, respectively, under the assumption of 30 minutes pretreatment setup time. For VMAT gated delivery, a 40% duty cycle, 2400MU/minute dose rate, and an extra 10 minutes per extra arc were assumed. Conclusion Clinically acceptable plans were
13. Near threshold ⁷Li(p,n) ⁷Be reaction as neutron source for BNCT.
Science.gov (United States)
Minsky, D M; Kreiner, A J
2015-12-01
(7)Li(p,n)(7)Be is an endothermic reaction and working near its threshold (1.88 MeV) has the advantage of neutron spectra with maximum energies of about 100 keV, considerably lower than at higher beam energies, or than using other neutron-producing reactions or as for the uranium fission spectrum, relevant for BNCT based on nuclear reactors. With this primary energy it is much easier to obtain the energies needed for treating deep seated tumors by BNCT (about 10 keV). This work studies bombarding energies up to 2.05 MeV, different beam incidence angles and the effect of the undesirable gamma production via the (7)Li(p,γp') (7)Li reaction.
14. Combined TL and 10B-alanine ESR dosimetry for BNCT.
Science.gov (United States)
Bartolotta, A; D'Oca, M C; Lo Giudice, B; Brai, M; Borio, R; Forini, N; Salvadori, P; Manera, S
2004-01-01
The dosimetric technique described in this paper is based on electron spin resonance (ESR) detectors using an alanine-boric compound acid enriched with (10)B, and beryllium oxide thermoluminescent (TL) detectors; with this combined dosimetry, it is possible to discriminate the doses due to thermal neutrons and gamma radiation in a mixed field. Irradiations were carried out inside the thermal column of a TRIGA MARK II water-pool-type research nuclear reactor, also used for Boron Neutron Capture therapy (BNCT) applications, with thermal neutron fluence from 10(9) to 10(14) nth cm(-2). The ESR dosemeters using the alanine-boron compound indicated ESR signals about 30-fold stronger than those using only alanine. Moreover, a negligible correction for the gamma contribution, measured with TL detectors, almost insensitive to thermal neutrons, was necessary. Therefore, a simultaneous analysis of our TL and ESR detectors allows discrimination between thermal neutron and gamma doses, as required in BNCT. PMID:15353720
15. The Phase I/II BNCT Trials at the Brookhaven medical research reactor: Critical considerations
International Nuclear Information System (INIS)
A phase I/II clinical trial of boronophenylalanine-fructose (BPA-F) mediated boron neutron capture therapy (BNCT) for Glioblastoma Multiforme (GBM) was initiated at Brookhaven National Laboratory (BNL) in 1994. Many critical issues were considered during the design of the first of many sequential dose escalation protocols. These critical issues included patient selection criteria, boron delivery agent, dose limits to the normal brain, dose escalation schemes for both neutron exposure and boron dose, and fractionation. As the clinical protocols progressed and evaluation of the tolerance of the central nervous system (CNS) to BPA-mediated BNCT at the BMRR continued new specifications were adopted. Clinical data reflecting the progression of the protocols will be presented to illustrate the steps taken and the reasons behind their adoption. (author)
16. The Argonne ACWL, a potential accelerator-based neutron source for BNCT
International Nuclear Information System (INIS)
THE CWDD (Continuous Wave Deuterium Demonstrator) accelerator was designed to accelerate 80 mA cw of D- to 7.5 MeV. Most of the hardware for the first 2 MeV was installed at Argonne and major subsystems had been commissioned when program funding from the Ballistic Missile Defense Organization ended in October 1993. Renamed the Argonne Continuous Wave Linac (ACWL), we are proposing to complete it to accelerate either deuterons to 2 MeV or protons to 3-3.5 MeV. Equipped with a beryllium or other light-element target, it would make a potent source of neutrons (on the order of 1013 n/s) for BNCT and/or neutron radiography. Project status and proposals for turning ACWL into a neutron source are reviewed, including the results of a computational study that was carried out to design a target/moderator to produce an epithermal neutron beam for BNCT. (orig.)
17. Vega library for processing DICOM data required in Monte Carlo verification of radiotherapy treatment plans
CERN Document Server
Locke, C
2008-01-01
Monte Carlo (MC) method provides the most accurate to-date dose calculations in heterogeneous media and complex geometries, and this spawns increasing interest in incorporating MC calculations to treatment planning quality assurance process. This process involves MC dose calculations for the treatment plans produced clinically. To perform these calculations a number of treatment plan parameters specifying radiation beam and patient geometries needs to be transferred to MC codes such as BEAMnrc and DOSXYZnrc. Extracting these parameters from DICOM files is not a trivial task that has previously been performed mostly using Matlab-based software. This paper describes DICOM tags that contain information required for MC modeling of conformal and IMRT plans, and reports development of an in-house DICOM interface through a library (named Vega) of platform-independent, object-oriented C++ codes. Vega library is small and succinct, offering just the fundamental functions for reading/modifying/writing DICOM files in a ...
Energy Technology Data Exchange (ETDEWEB)
Nigg, D; Wessol, D; Wemple, C; Harkin, G; Hartmann-Siantar, C
2002-08-20
The Idaho National Engineering and Environmental Laboratory (INEEL) has long been active in development of advanced Monte-Carlo based computational dosimetry and treatment planning methods and software for advanced radiotherapy, with a particular focus on Neutron Capture Therapy (NCT) and, to a somewhat lesser extent, Fast-Neutron Therapy. The most recent INEEL software system of this type is known as SERA, Simulation Environment for Radiotherapy Applications. As a logical next step in the development of modern radiotherapy planning tools to support the most advanced research, INEEL and Lawrence Livermore National Laboratory (LLNL), the developers of the PEREGRTNE computational engine for radiotherapy treatment planning applications, have recently launched a new project to collaborate in the development of a ''next-generation'' multi-modality treatment planning software system that will be useful for all modern forms of radiotherapy.
19. The epithermal neutron beam for BNCT under construction at TAPIRO: Physics
Energy Technology Data Exchange (ETDEWEB)
Burn, K W [ENEA- Ente Nuove Tecnologie Energia e Ambiente, FIS-NUC, Via M.M. Sole 4, 40129 Bologna (Italy); Casalini, L [ENEA- Ente Nuove Tecnologie Energia e Ambiente, FIS-NUC, Via M.M. Sole 4, 40129 Bologna (Italy); Mondini, D [Dipartimento di Ingegneria Meccanica, Nucleare e della Produzione (DIMNP), Universita di Pisa, Via Diotisalvi 2, 56126 Pisa (Italy); Nava, E [ENEA- Ente Nuove Tecnologie Energia e Ambiente, FIS-NUC, Via M.M. Sole 4, 40129 Bologna (Italy); Rosi, G [ENEA - Ente Nuove Tecnologie Energia e Ambiente, FIS-ION, Via Anguillarese 301, 00060 Rome (Italy); Tinti, R [ENEA- Ente Nuove Tecnologie Energia e Ambiente, FIS-NUC, Via M.M. Sole 4, 40129 Bologna (Italy)
2006-05-15
A column to provide an epithermal neutron beam suitable for experimental and clinical BNCT is nearing completion at the TAPIRO reactor (ENEA Casaccia, Rome). TAPIRO is a compact, low power (5 kW), helium-cooled, fast reactor. It has a hard neutron spectrum relative even to other fast reactors. In this paper some of the basic physics aspects of designing an epithermal neutron beam are considered, with reference to the TAPIRO beam.
20. A feasibility design study on a neutron spectrometer for BNCT with liquid moderator.
Science.gov (United States)
Tamaki, S; Sato, F; Murata, I
2015-12-01
Neutrons generated by accelerators have various energy spectra. However, only limited methods are available to measure the whole neutron energy spectrum, especially when including the epithermal region that is normally used in BNCT. In the present study, we carried out the design study on a new neutron spectrometer that can measure such a neutron spectrum more accurately, precisely and with higher energy resolution, using an unfolding technique and a liquid moderator.
1. Neutron collimator design of neutron radiography based on the BNCT facility
OpenAIRE
Yang, XP.; Yu, BX; Li, YG; Peng, D; Lu, J.; Zhang, GL.; Zhao, H.; Zhang, AW.; Li, CY.; Liu, WJ; Hu, T.; Lv, JG.
2013-01-01
For the research of CCD neutron radiography, a neutron collimator was designed based on the exit of thermal neutron of the Boron Neutron Capture Therapy (BNCT) reactor. Based on the Geant4 simulations, the preliminary choice of the size of the collimator was determined. The materials were selected according to the literature data. Then, a collimator was constructed and tested on site. The results of experiment and simulation show that the thermal neutron flux at the end of theneutron collimat...
2. Dosimetric verification of radiotherapy treatment planning systems: Results of IAEA pilot study
International Nuclear Information System (INIS)
Background and purpose: The methodology developed by IAEA for dosimetric quality control of treatment planning systems has been tested in different hospitals through a pilot study. The aim was to verify the methodology and observe the range of deviations between planned and delivered doses in 3D conformal radiotherapy in situations close to a clinical setting. Material and methods: The methodology was based on an anthropomorphic phantom representing the human thorax, and simulates the whole chain of external beam radiotherapy treatment planning activities. The phantom was scanned using computed tomography and eight test cases were planned on treatment planning systems which imitate different irradiation geometries found in conformal radiotherapy. The doses were measured with ion chambers, and the deviation between measured and treatment planning system calculated doses was reported. This methodology, which employs the same phantom and the same set of test cases, was tested in 17 different hospitals which were using 14 different algorithms/inhomogeneity correction methods implemented in different treatment planning systems. Results: A total of 53 clinical test case datasets for different energies and calculation algorithms were produced. Most of the systems with advanced algorithms complied with predefined agreement criteria. Dose differences more than 20% were discovered for some of the simple algorithms and high energy X-ray beams. The number of deviations outside agreement criteria increases with the beam energy and decreases with advancement of the treatment planning system calculation algorithm. Conclusions: Large deviations exist in some simple dose calculation algorithms, therefore more advanced algorithms would be preferable and therefore should be implemented in clinical practice. The test cases that could be performed in reasonable time would help the users to appreciate the possibilities of their system and understand its limitations
3. Coverage-based treatment planning: optimizing the IMRT PTV to meet a CTV coverage criterion.
Science.gov (United States)
Gordon, J J; Siebers, J V
2009-03-01
This work demonstrates an iterative approach-referred to as coverage-based treatment planning-designed to produce treatment plans that ensure target coverage for a specified percentage of setup errors. In this approach the clinical target volume to planning target volume (CTV-to-PTV) margin is iteratively adjusted until the specified CTV coverage is achieved. The advantage of this approach is that it automatically compensates for the dosimetric margin around the CTV, i.e., the extra margin that is created when the dose distribution extends beyond the PTV. When applied to 27 prostate plans, this approach reduced the average CTV-to-PTV margin from 5 to 2.8 mm. This reduction in PTV size produced a corresponding decrease in the volume of normal tissue receiving high dose. The total volume of tissue receiving > or =65 Gy was reduced on average by 19.3% or about 48 cc. Individual reductions varied from 8.7% to 28.6%. The volume of bladder receiving > or =60 Gy was reduced on average by 5.6% (reductions for individuals varied from 1.7% to 10.6%), and the volume of periprostatic rectum receiving > or =65 Gy was reduced on average by 4.9% (reductions for individuals varied from 0.9% to 12.3%). The iterative method proposed here represents a step toward a probabilistic treatment planning algorithm which can generate dose distributions (i.e., treated volumes) that closely approximate a specified level of coverage in the presence of geometric uncertainties. The general principles of coverage-based treatment planning are applicable to arbitrary treatment sites and delivery techniques. Importantly, observed deviations between coverage implied by specified CTV-to-PTV margins and coverage achieved by a given treatment plan imply a generic need to perform coverage probability analysis on a per-plan basis to ensure that the desired level of coverage is achieved. PMID:19378757
4. Robustness of IPSA optimized high-dose-rate prostate brachytherapy treatment plans to catheter displacements
Science.gov (United States)
Whitaker, May
2016-01-01
Purpose Inverse planning simulated annealing (IPSA) optimized brachytherapy treatment plans are characterized with large isolated dwell times at the first or last dwell position of each catheter. The potential of catheter shifts relative to the target and organs at risk in these plans may lead to a more significant change in delivered dose to the volumes of interest relative to plans with more uniform dwell times. Material and methods This study aims to determine if the Nucletron Oncentra dwell time deviation constraint (DTDC) parameter can be optimized to improve the robustness of high-dose-rate (HDR) prostate brachytherapy plans to catheter displacements. A set of 10 clinically acceptable prostate plans were re-optimized with a DTDC parameter of 0 and 0.4. For each plan, catheter displacements of 3, 7, and 14 mm were retrospectively applied and the change in dose volume histogram (DVH) indices and conformity indices analyzed. Results The robustness of clinically acceptable prostate plans to catheter displacements in the caudal direction was found to be dependent on the DTDC parameter. A DTDC value of 0 improves the robustness of planning target volume (PTV) coverage to catheter displacements, whereas a DTDC value of 0.4 improves the robustness of the plans to changes in hotspots. Conclusions The results indicate that if used in conjunction with a pre-treatment catheter displacement correction protocol and a tolerance of 3 mm, a DTDC value of 0.4 may produce clinically superior plans. However, the effect of the DTDC parameter in plan robustness was not observed to be as strong as initially suspected. PMID:27504129
5. Uncertainty in hyperthermia treatment planning: the need for robust system design
NARCIS (Netherlands)
M. de Greef; H.P. Kok; D. Correia; P.P. Borsboom; A. Bel; J. Crezee
2011-01-01
Hyperthermia treatment planning (HTP) is an important tool to improve the quality of hyperthermia treatment. It is a practical way of designing new hyperthermia systems and can be used to optimize the phase and amplitude settings to achieve optimal heating. One of the main challenges to be dealt wit
6. Treatment planning of electroporation-based medical interventions: electrochemotherapy, gene electrotransfer and irreversible electroporation
International Nuclear Information System (INIS)
In recent years, cancer electrochemotherapy (ECT), gene electrotransfer for gene therapy and DNA vaccination (GET) and tissue ablation with irreversible electroporation (IRE) have all entered clinical practice. We present a method for a personalized treatment planning procedure for ECT, GET and IRE, based on medical image analysis, numerical modelling of electroporation and optimization with the genetic algorithm, and several visualization tools for treatment plan assessment. Each treatment plan provides the attending physician with optimal positions of electrodes in the body and electric pulse parameters for optimal electroporation of the target tissues. For the studied case of a deep-seated tumour, the optimal treatment plans for ECT and IRE require at least two electrodes to be inserted into the target tissue, thus lowering the necessary voltage for electroporation and limiting damage to the surrounding healthy tissue. In GET, it is necessary to place the electrodes outside the target tissue to prevent damage to target cells intended to express the transfected genes. The presented treatment planning procedure is a valuable tool for clinical and experimental use and evaluation of electroporation-based treatments. (paper)
7. Treatment planning of electroporation-based medical interventions: electrochemotherapy, gene electrotransfer and irreversible electroporation
Science.gov (United States)
Zupanic, Anze; Kos, Bor; Miklavcic, Damijan
2012-09-01
In recent years, cancer electrochemotherapy (ECT), gene electrotransfer for gene therapy and DNA vaccination (GET) and tissue ablation with irreversible electroporation (IRE) have all entered clinical practice. We present a method for a personalized treatment planning procedure for ECT, GET and IRE, based on medical image analysis, numerical modelling of electroporation and optimization with the genetic algorithm, and several visualization tools for treatment plan assessment. Each treatment plan provides the attending physician with optimal positions of electrodes in the body and electric pulse parameters for optimal electroporation of the target tissues. For the studied case of a deep-seated tumour, the optimal treatment plans for ECT and IRE require at least two electrodes to be inserted into the target tissue, thus lowering the necessary voltage for electroporation and limiting damage to the surrounding healthy tissue. In GET, it is necessary to place the electrodes outside the target tissue to prevent damage to target cells intended to express the transfected genes. The presented treatment planning procedure is a valuable tool for clinical and experimental use and evaluation of electroporation-based treatments.
8. Retrospective review of the clinical BNCT trial at Brookhaven National Laboratory
Energy Technology Data Exchange (ETDEWEB)
Diaz, A.Z.; Chanana, A.D.; Coderre, J.A.; Ma, R. [Brookhaven National Laboratory, Medical Department, Upton, NY (United States)
2000-10-01
The primary objective of the phase I/II dose escalation studies was to evaluate the safety of the boronophenylalanine-fructose (BPA-F) mediated boron neutron capture therapy (BNCT) in subjects with glioblastoma multiforme (GBM). A secondary objective was to retrospectively assess the palliation of GBM by BNCT. Fifty-three subjects with GBM were treated under multiple dose escalation protocols at the Brookhaven Medical Research Reactor (BMRR). Twenty-six subjects were treated using one field, 17 subjects were treated using 2 fields and 10 subjects were treated using 3 fields. BPA-F related toxicity was not observed. The maximum radiation dose to a volume of approximately 1 cc of the normal brain varied from 8.9 to 15.9 gray-equivalent (Gy-Eq). The volume-weighted average radiation dose to normal brain varied from 1.9 to 9.5 Gy-Eq. Six RTOG (Radiation Therapy Oncology Group) grade 3 or 4 toxicities were attributed to BNCT. Four of the 53 subjects are still alive with 3 of them free of recurrent disease with over two years follow-up. The median times to progression and median survival time from diagnosis were 28.4 weeks and 12.8 months respectively. (author)
9. Development of the high power multi-stage type circulator for BNCT system
International Nuclear Information System (INIS)
The process for BNCT begins with a pharmaceutical agent that carries a neutron capture agent containing 10B (Boron 10) selectively into tumor cells. Thermal or epi-thermal neutrons then interact with the 10B and produce α and 7Li-particles. So far, BNCT have been provided only by nuclear reactors, because a neutron intensity of 1x109n/cm2/s, with energies between 0.5-eV and 10-keV is required. To realize BNCT using accelerator technologies, one of the big issuer is the high duty rf system, which will be used for 324 MHz, 1.2 MW peak klystron, 1 msec of an rf pulse width and a 200 Hz of cycle. A high power circulator is the most critical component among the waveguide system. It was redesigned from a linear accelerator of J-PARC to meet the 20% of a duty factor using a high saturation magnetization 4piMs has high curie temperature. Also, it was used thin ferrite layer to reduce the temperature rise and to reduce the temperature sensitivity. This paper reports the design work, the manufacture and a low power measurement. (author)
10. FoCa: a modular treatment planning system for proton radiotherapy with research and educational purposes
Science.gov (United States)
Sánchez-Parcerisa, D.; Kondrla, M.; Shaindlin, A.; Carabe, A.
2014-12-01
FoCa is an in-house modular treatment planning system, developed entirely in MATLAB, which includes forward dose calculation of proton radiotherapy plans in both active and passive modalities as well as a generic optimization suite for inverse treatment planning. The software has a dual education and research purpose. From the educational point of view, it can be an invaluable teaching tool for educating medical physicists, showing the insights of a treatment planning system from a well-known and widely accessible software platform. From the research point of view, its current and potential uses range from the fast calculation of any physical, radiobiological or clinical quantity in a patient CT geometry, to the development of new treatment modalities not yet available in commercial treatment planning systems. The physical models in FoCa were compared with the commissioning data from our institution and show an excellent agreement in depth dose distributions and longitudinal and transversal fluence profiles for both passive scattering and active scanning modalities. 3D dose distributions in phantom and patient geometries were compared with a commercial treatment planning system, yielding a gamma-index pass rate of above 94% (using FoCa’s most accurate algorithm) for all cases considered. Finally, the inverse treatment planning suite was used to produce the first prototype of intensity-modulated, passive-scattered proton therapy, using 13 passive scattering proton fields and multi-leaf modulation to produce a concave dose distribution on a cylindrical solid water phantom without any field-specific compensator.
11. FoCa: a modular treatment planning system for proton radiotherapy with research and educational purposes
International Nuclear Information System (INIS)
FoCa is an in-house modular treatment planning system, developed entirely in MATLAB, which includes forward dose calculation of proton radiotherapy plans in both active and passive modalities as well as a generic optimization suite for inverse treatment planning. The software has a dual education and research purpose. From the educational point of view, it can be an invaluable teaching tool for educating medical physicists, showing the insights of a treatment planning system from a well-known and widely accessible software platform. From the research point of view, its current and potential uses range from the fast calculation of any physical, radiobiological or clinical quantity in a patient CT geometry, to the development of new treatment modalities not yet available in commercial treatment planning systems. The physical models in FoCa were compared with the commissioning data from our institution and show an excellent agreement in depth dose distributions and longitudinal and transversal fluence profiles for both passive scattering and active scanning modalities. 3D dose distributions in phantom and patient geometries were compared with a commercial treatment planning system, yielding a gamma-index pass rate of above 94% (using FoCa’s most accurate algorithm) for all cases considered. Finally, the inverse treatment planning suite was used to produce the first prototype of intensity-modulated, passive-scattered proton therapy, using 13 passive scattering proton fields and multi-leaf modulation to produce a concave dose distribution on a cylindrical solid water phantom without any field-specific compensator. (paper)
12. IMRT, IGRT, SBRT - Advances in the Treatment Planning and Delivery of Radiotherapy
CERN Document Server
Meyer, JL
2011-01-01
Over the last 4 years, IMRT, IGRT, SBRT: Advances in the Treatment Planning and Delivery of Radiotherapy has become a standard reference in the field. During this time, however, significant progress in high-precision technologies for the planning and delivery of radiotherapy in cancer treatment has called for a second edition to include these new developments. Thoroughly updated and extended, this new edition offers a comprehensive guide and overview of these new technologies and the many clinical treatment programs that bring them into practical use. Advances in intensity-modulated radiothera
13. Tridimensional Treatment Planning and Rapid Prototyping for Maxillofacial Prosthesis
Institute of Scientific and Technical Information of China (English)
ZHANGWen-qiang; YUANJian-bing; YEMing; HUANGXue-mei; WANGCheng-tao
2004-01-01
The currert stmulation planing systmes for maxillofacial prosthesis surgery were used to extrapolate 3D surgical movements and outcomes based on the 2D radiographs,which were inadequate for complex surgical movements A 3D treatmenl planning system based on the computerized tomography(CT)data was presented A 3D data field was costructed out of the sectional image stack through linear interpolation after objectire tissue segmentation and using the marching cubes algorithm method,the triangular mesh model and 3D geometric model of diseased facial skeleton were reconstructed then the model was cut,the segments were moved or totated to their predicted positions,and angles and distances were measured after triangular mesh model was decimaled a RP model was manufactured for surgical simulation and prosthesis design The system was used in clinic with more than fifty cases and technically wilidated with success.
14. Human applications of the INEL patient treatment planning system
Energy Technology Data Exchange (ETDEWEB)
Wheeler, F.; Wessol, D.; Atkinson, C.; Nigg, D. [Idaho National Accelerator Lab., Idaho Falls, ID (United States)
1995-11-01
During the past few years, murine and large animal research, as well as human studies have provided data to the point where human clinical trials have been initiated at the BMRR using BPA-F for gliomas and at the Massachusetts Institute of Technology Reactor (MITR) using BPA for melanomas of the extremeties. It is expected that glioma trials using BSH will proceed soon at the Petten High Flux Reactor (HFR) in the Netherlands. The first human glioma epithermal boron neutron capture therapy application was performed at the BMRR in the fall of 1994. This was a collaborative effort by BNL, Beth Israel Manhattan hospital, and INEL. The INEL planning system was chosen to perform dose predictions for this application.
15. A planning study investigating dual-gated volumetric arc stereotactic treatment of primary renal cell carcinoma
International Nuclear Information System (INIS)
This is a planning study investigating the dosimetric advantages of gated volumetric-modulated arc therapy (VMAT) to the end-exhale and end-inhale breathing phases for patients undergoing stereotactic treatment of primary renal cell carcinoma. VMAT plans were developed from the end-inhale (VMATinh) and the end-exhale (VMATexh) phases of the breathing cycle as well as a VMAT plan and 3-dimensional conformal radiation therapy plan based on an internal target volume (ITV) (VMATitv). An additional VMAT plan was created by giving the respective gated VMAT plan a 50% weighting and summing the inhale and exhale plans together to create a summed gated plan. Dose to organs at risk (OARs) as well as comparison of intermediate and low-dose conformity was evaluated. There was no difference in the volume of healthy tissue receiving the prescribed dose for the planned target volume (PTV) (CI100%) for all the VMAT plans; however, the mean volume of healthy tissue receiving 50% of the prescribed dose for the PTV (CI50%) values were 4.7 (± 0.2), 4.6 (± 0.2), and 4.7 (± 0.6) for the VMATitv, VMATinh, and VMATexh plans, respectively. The VMAT plans based on the exhale and inhale breathing phases showed a 4.8% and 2.4% reduction in dose to 30 cm3 of the small bowel, respectively, compared with that of the ITV-based VMAT plan. The summed gated VMAT plans showed a 6.2% reduction in dose to 30 cm3 of the small bowel compared with that of the VMAT plans based on the ITV. Additionally, when compared with the inhale and the exhale VMAT plans, a 4% and 1.5%, respectively, reduction was observed. Gating VMAT was able to reduce the amount of prescribed, intermediate, and integral dose to healthy tissue when compared with VMAT plans based on an ITV. When summing the inhale and exhale plans together, dose to healthy tissue and OARs was optimized. However, gating VMAT plans would take longer to treat and is a factor that needs to be considered
16. A planning study investigating dual-gated volumetric arc stereotactic treatment of primary renal cell carcinoma
Energy Technology Data Exchange (ETDEWEB)
Devereux, Thomas, E-mail: [email protected] [Radiation Therapy Services, Peter MacCallum Cancer Centre, Melbourne (Australia); Pham, Daniel [Radiation Therapy Services, Peter MacCallum Cancer Centre, Melbourne (Australia); Kron, Tomas [Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne (Australia); Sir Peter MacCallum Department of Oncology, Melbourne University, Melbourne (Australia); Foroudi, Farshad [Sir Peter MacCallum Department of Oncology, Melbourne University, Melbourne (Australia); Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne (Australia); Supple, Jeremy [School of Applied Sciences, Royal Melbourne Institute of Technology, Melbourne (Australia); Siva, Shankar [Sir Peter MacCallum Department of Oncology, Melbourne University, Melbourne (Australia); Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne (Australia)
2015-04-01
This is a planning study investigating the dosimetric advantages of gated volumetric-modulated arc therapy (VMAT) to the end-exhale and end-inhale breathing phases for patients undergoing stereotactic treatment of primary renal cell carcinoma. VMAT plans were developed from the end-inhale (VMATinh) and the end-exhale (VMATexh) phases of the breathing cycle as well as a VMAT plan and 3-dimensional conformal radiation therapy plan based on an internal target volume (ITV) (VMATitv). An additional VMAT plan was created by giving the respective gated VMAT plan a 50% weighting and summing the inhale and exhale plans together to create a summed gated plan. Dose to organs at risk (OARs) as well as comparison of intermediate and low-dose conformity was evaluated. There was no difference in the volume of healthy tissue receiving the prescribed dose for the planned target volume (PTV) (CI100%) for all the VMAT plans; however, the mean volume of healthy tissue receiving 50% of the prescribed dose for the PTV (CI50%) values were 4.7 (± 0.2), 4.6 (± 0.2), and 4.7 (± 0.6) for the VMATitv, VMATinh, and VMATexh plans, respectively. The VMAT plans based on the exhale and inhale breathing phases showed a 4.8% and 2.4% reduction in dose to 30 cm{sup 3} of the small bowel, respectively, compared with that of the ITV-based VMAT plan. The summed gated VMAT plans showed a 6.2% reduction in dose to 30 cm{sup 3} of the small bowel compared with that of the VMAT plans based on the ITV. Additionally, when compared with the inhale and the exhale VMAT plans, a 4% and 1.5%, respectively, reduction was observed. Gating VMAT was able to reduce the amount of prescribed, intermediate, and integral dose to healthy tissue when compared with VMAT plans based on an ITV. When summing the inhale and exhale plans together, dose to healthy tissue and OARs was optimized. However, gating VMAT plans would take longer to treat and is a factor that needs to be considered.
17. Independent calculation of dose distributions for helical tomotherapy using a conventional treatment planning system
Energy Technology Data Exchange (ETDEWEB)
Klüter, Sebastian, E-mail: [email protected]; Schubert, Kai; Lissner, Steffen; Sterzing, Florian; Oetzel, Dieter; Debus, Jürgen [Department of Radiation Oncology, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany, and Heidelberg Institute for Radiation Oncology (HIRO), Im Neuenheimer Feld 400, 69120 Heidelberg, Germany, and German Consortium for Translational Cancer Research (DKTK), Im Neuenheimer Feld 400, 69120 Heidelberg (Germany); Schlegel, Wolfgang [German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Oelfke, Uwe [German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG (United Kingdom); Nill, Simeon [Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG (United Kingdom)
2014-08-15
Purpose: The dosimetric verification of treatment plans in helical tomotherapy usually is carried out via verification measurements. In this study, a method for independent dose calculation of tomotherapy treatment plans is presented, that uses a conventional treatment planning system with a pencil kernel dose calculation algorithm for generation of verification dose distributions based on patient CT data. Methods: A pencil beam algorithm that directly uses measured beam data was configured for dose calculation for a tomotherapy machine. Tomotherapy treatment plans were converted into a format readable by an in-house treatment planning system by assigning each projection to one static treatment field and shifting the calculation isocenter for each field in order to account for the couch movement. The modulation of the fluence for each projection is read out of the delivery sinogram, and with the kernel-based dose calculation, this information can directly be used for dose calculation without the need for decomposition of the sinogram. The sinogram values are only corrected for leaf output and leaf latency. Using the converted treatment plans, dose was recalculated with the independent treatment planning system. Multiple treatment plans ranging from simple static fields to real patient treatment plans were calculated using the new approach and either compared to actual measurements or the 3D dose distribution calculated by the tomotherapy treatment planning system. In addition, dose–volume histograms were calculated for the patient plans. Results: Except for minor deviations at the maximum field size, the pencil beam dose calculation for static beams agreed with measurements in a water tank within 2%/2 mm. A mean deviation to point dose measurements in the cheese phantom of 0.89% ± 0.81% was found for unmodulated helical plans. A mean voxel-based deviation of −0.67% ± 1.11% for all voxels in the respective high dose region (dose values >80%), and a mean local
18. Independent calculation of dose distributions for helical tomotherapy using a conventional treatment planning system
International Nuclear Information System (INIS)
Purpose: The dosimetric verification of treatment plans in helical tomotherapy usually is carried out via verification measurements. In this study, a method for independent dose calculation of tomotherapy treatment plans is presented, that uses a conventional treatment planning system with a pencil kernel dose calculation algorithm for generation of verification dose distributions based on patient CT data. Methods: A pencil beam algorithm that directly uses measured beam data was configured for dose calculation for a tomotherapy machine. Tomotherapy treatment plans were converted into a format readable by an in-house treatment planning system by assigning each projection to one static treatment field and shifting the calculation isocenter for each field in order to account for the couch movement. The modulation of the fluence for each projection is read out of the delivery sinogram, and with the kernel-based dose calculation, this information can directly be used for dose calculation without the need for decomposition of the sinogram. The sinogram values are only corrected for leaf output and leaf latency. Using the converted treatment plans, dose was recalculated with the independent treatment planning system. Multiple treatment plans ranging from simple static fields to real patient treatment plans were calculated using the new approach and either compared to actual measurements or the 3D dose distribution calculated by the tomotherapy treatment planning system. In addition, dose–volume histograms were calculated for the patient plans. Results: Except for minor deviations at the maximum field size, the pencil beam dose calculation for static beams agreed with measurements in a water tank within 2%/2 mm. A mean deviation to point dose measurements in the cheese phantom of 0.89% ± 0.81% was found for unmodulated helical plans. A mean voxel-based deviation of −0.67% ± 1.11% for all voxels in the respective high dose region (dose values >80%), and a mean local
19. Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a (60)Co Magnetic Resonance Image Guidance Radiation Therapy System
DEFF Research Database (Denmark)
Wooten, H Omar; Green, Olga; Yang, Min;
2015-01-01
PURPOSE: This work describes a commercial treatment planning system, its technical features, and its capabilities for creating (60)Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. METHODS AND MATERIALS......: The ViewRay treatment planning system (Oakwood Village, OH) was used to create (60)Co IMRT treatment plans for 33 cancer patients with disease in the abdominal, pelvic, thorax, and head and neck regions using physician-specified patient-specific target coverage and organ at risk (OAR) objectives. Backup...... plans using a third-party linear accelerator (linac)-based planning system were also created. Plans were evaluated by attending physicians and approved for treatment. The (60)Co and linac plans were compared by evaluating conformity numbers (CN) with 100% and 95% of prescription reference doses...
20. Predicting Substance Abuse Treatment Completion using a New Scale Based on the Theory of Planned Behavior
OpenAIRE
Zemore, Sarah E.; Ajzen, Icek
2013-01-01
We examined whether a 9-item scale based on the theory of planned behavior (TPB) predicted substance abuse treatment completion. Data were collected at a public, outpatient program among clients initiating treatment (N=200). Baseline surveys included measures of treatment-related attitudes, norms, perceived control, and intention; discharge status was collected from program records. As expected, TPB attitude and control components independently predicted intention (model R-squared=.56), and i...
1. Towards the development of an error checker for radiotherapy treatment plans: a preliminary study
International Nuclear Information System (INIS)
Major accidents can happen during radiotherapy, with an extremely severe consequence to both patients and clinical professionals. We propose to use machine learning and data mining techniques to help detect large human errors in a radiotherapy treatment plan, as a complement to human inspection. One such technique is computer clustering. The basic idea of using clustering algorithms for outlier detection is to first cluster (based on the treatment parameters) a large number of patient treatment plans. Then, when checking a new treatment plan, the parameters of the plan will be tested to see whether or not they belong to the established clusters. If not, they will be considered as 'outliers' and therefore highlighted to catch the attention of the human chart checkers. As a preliminary study, we applied the K-means clustering algorithm to a simple patient model, i.e., 'four-field' box prostate treatment. One thousand plans were used to build the clusters while another 650 plans were used to test the proposed method. It was found that there are eight distinct clusters. At the error levels of ±100% of the original values of the monitor unit, the detection rate is about 100%. At ±50% error level, the detection rate is about 80%. The false positive rate is about 10%. When purposely changing the beam energy to a value different from that in the treatment plan, the detection rate is 100% for posterior, right-lateral and left-lateral fields, and about 77% for the anterior field. This preliminary work has shown promise for developing the proposed automatic outlier detection software, although more efforts will still be required
2. Towards the development of an error checker for radiotherapy treatment plans: a preliminary study
Energy Technology Data Exchange (ETDEWEB)
Azmandian, Fatemeh [Department of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115 (United States); Kaeli, David [Department of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115 (United States); Dy, Jennifer G [Department of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115 (United States); Hutchinson, Elizabeth [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 (United States); Ancukiewicz, Marek [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 (United States); Niemierko, Andrzej [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 (United States); Jiang, Steve B [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 (United States)
2007-11-07
Major accidents can happen during radiotherapy, with an extremely severe consequence to both patients and clinical professionals. We propose to use machine learning and data mining techniques to help detect large human errors in a radiotherapy treatment plan, as a complement to human inspection. One such technique is computer clustering. The basic idea of using clustering algorithms for outlier detection is to first cluster (based on the treatment parameters) a large number of patient treatment plans. Then, when checking a new treatment plan, the parameters of the plan will be tested to see whether or not they belong to the established clusters. If not, they will be considered as 'outliers' and therefore highlighted to catch the attention of the human chart checkers. As a preliminary study, we applied the K-means clustering algorithm to a simple patient model, i.e., 'four-field' box prostate treatment. One thousand plans were used to build the clusters while another 650 plans were used to test the proposed method. It was found that there are eight distinct clusters. At the error levels of {+-}100% of the original values of the monitor unit, the detection rate is about 100%. At {+-}50% error level, the detection rate is about 80%. The false positive rate is about 10%. When purposely changing the beam energy to a value different from that in the treatment plan, the detection rate is 100% for posterior, right-lateral and left-lateral fields, and about 77% for the anterior field. This preliminary work has shown promise for developing the proposed automatic outlier detection software, although more efforts will still be required.
3. Comparative study of old and new versions of treatment planning system using dose volume histogram indices of clinical plans.
Science.gov (United States)
Krishna, Gangarapu Sri; Srinivas, Vuppu; Ayyangar, K M; Reddy, Palreddy Yadagiri
2016-01-01
Recently, Eclipse treatment planning system (TPS) version 8.8 was upgraded to the latest version 13.6. It is customary that the vendor gives training on how to upgrade the existing software to the new version. However, the customer is provided less inner details about changes in the new software version. According to manufacturer, accuracy of point dose calculations and irregular treatment planning is better in the new version (13.6) compared to the old version (8.8). Furthermore, the new version uses voxel-based calculations while the earlier version used point dose calculations. Major difference in intensity-modulated radiation therapy (IMRT) plans was observed between the two versions after re-optimization and re-calculations. However, minor difference was observed for IMRT cases after performing only re-calculations. It is recommended TPS quality assurance to be performed after any major upgrade of software. This can be done by performing dose calculation comparisons in TPS. To assess the difference between the versions, 25 clinical cases from the old version were compared keeping all the patient data intact including the monitor units and comparing the differences in dose calculations using dose volume histogram (DVH) analysis. Along with DVH analysis, uniformity index, conformity index, homogeneity index, and dose spillage index were also compared for both versions. The results of comparative study are presented in this paper. PMID:27651566
4. Comparative study of old and new versions of treatment planning system using dose volume histogram indices of clinical plans
Science.gov (United States)
Krishna, Gangarapu Sri; Srinivas, Vuppu; Ayyangar, K. M.; Reddy, Palreddy Yadagiri
2016-01-01
Recently, Eclipse treatment planning system (TPS) version 8.8 was upgraded to the latest version 13.6. It is customary that the vendor gives training on how to upgrade the existing software to the new version. However, the customer is provided less inner details about changes in the new software version. According to manufacturer, accuracy of point dose calculations and irregular treatment planning is better in the new version (13.6) compared to the old version (8.8). Furthermore, the new version uses voxel-based calculations while the earlier version used point dose calculations. Major difference in intensity-modulated radiation therapy (IMRT) plans was observed between the two versions after re-optimization and re-calculations. However, minor difference was observed for IMRT cases after performing only re-calculations. It is recommended TPS quality assurance to be performed after any major upgrade of software. This can be done by performing dose calculation comparisons in TPS. To assess the difference between the versions, 25 clinical cases from the old version were compared keeping all the patient data intact including the monitor units and comparing the differences in dose calculations using dose volume histogram (DVH) analysis. Along with DVH analysis, uniformity index, conformity index, homogeneity index, and dose spillage index were also compared for both versions. The results of comparative study are presented in this paper. PMID:27651566
5. Amelogenesis imperfecta and the treatment plan - interdisciplinary team approach.
Science.gov (United States)
Suchancova, B; Holly, D; Janska, M; Stebel, J; Lysy, J; Thurzo, A; Sasinek, S
2014-01-01
Amelogenesis imperfecta is a set of hereditary defects representing mainly the development defects of enamel without the presence of whole-body symptoms. Developmental disorders can manifest a complete absence of enamel, which is caused by improper differentiation of ameloblasts. This article describes the diagnosis and treatment of a patient with amelogenesis imperfecta, as well as the need for interdisciplinary cooperation to achieve the best possible morphological, skeletal, functional and aesthetic rehabilitation of the patients with this diagnosis. Furthermore, the article reviews literature dealing with other anomalies occurring in association with amelogenesis imperfect (Fig. 12, Ref. 20).
6. A simple DVH generation technique from various radiotherapy treatment planning systems for independent information system
CERN Document Server
Min, Byung Jun; Jeong, Il Sun; Lee, Hyebin
2015-01-01
In recent years, the use of PACS for radiation therapy has become the norm in hospital environment and has suggested for collecting data and management from different TPSs with DICOM objects. However, some TPS does not provide the DVH exportation with text or other format. In addition, plan review systems for various TPSs often allow DVH recalculation with different algorithms. These algorithms result in the inevitable discrepancy between the values obtained with the recalculation and those obtained with TPS itself. The purpose of this study was to develop a simple method for generating reproducible DVH values obtained from the TPSs. Treatment planning information including structures and delivered dose was exported by the DICOM format from planning systems. The supersampling and trilinear interpolation methods were employed to calculate DVH data from 35 treatment plans. The discrepancies between DVHs extracted from each TPS and the proposed calculation method were evaluated with respect to the supersampling ...
7. Records needed for orthodontic diagnosis and treatment planning: a systematic review.
Directory of Open Access Journals (Sweden)
Robine J Rischen
Full Text Available BACKGROUND: Traditionally, dental models, facial and intra-oral photographs and a set of two-dimensional radiographs are used for orthodontic diagnosis and treatment planning. As evidence is lacking, the discussion is ongoing which specific records are needed for the process of making an orthodontic treatment plan. OBJECTIVE: To estimate the contribution and importance of different diagnostic records for making an orthodontic diagnosis and treatment plan. DATA SOURCES: An electronic search in PubMed (1948-July 2012, EMBASE Excerpta Medica (1980-July 2012, CINAHL (1982-July 2012, Web of Science (1945-July 2012, Scopus (1996-July 2012, and Cochrane Library (1993-July 2012 was performed. Additionally, a hand search of the reference lists of included studies was performed to identify potentially eligible studies. There was no language restriction. STUDY SELECTION: The patient, intervention, comparator, outcome (pico question formulated for this study was as follows: for patients who need orthodontic treatment (P, will the use of record set X (I compared with record set Y (C change the treatment plan (O? Only primary publications were included. DATA EXTRACTION: Independent extraction of data and quality assessment was performed by two observers. RESULTS: Of the 1041 publications retrieved, 17 met the inclusion criteria. Of these, 4 studies were of high quality. Because of the limited number of high quality studies and the differences in study designs, patient characteristics, and reference standard or index test, a meta-analysis was not possible. CONCLUSION: Cephalograms are not routinely needed for orthodontic treatment planning in Class II malocclusions, digital models can be used to replace plaster casts, and cone-beam computed tomography radiographs can be indicated for impacted canines. Based on the findings of this review, the minimum record set required for orthodontic diagnosis and treatment planning could not be defined. SYSTEMATIC REVIEW
8. The adaptation of megavoltage cone beam CT for use in standard radiotherapy treatment planning
Science.gov (United States)
Thomas, T. Hannah Mary; Devakumar, D.; Purnima, S.; Ravindran, B. Paul
2009-04-01
Potential areas where megavoltage computed tomography (MVCT) could be used are second- and third-phase treatment planning in 3D conformal radiotherapy and IMRT, adaptive radiation therapy, single fraction palliative treatment and for the treatment of patients with metal prostheses. A feasibility study was done on using MV cone beam CT (CBCT) images generated by proprietary 3D reconstruction software based on the FDK algorithm for megavoltage treatment planning. The reconstructed images were converted to a DICOM file set. The pixel values of megavoltage cone beam computed tomography (MV CBCT) were rescaled to those of kV CT for use with a treatment planning system. A calibration phantom was designed and developed for verification of geometric accuracy and CT number calibration. The distance measured between two marker points on the CBCT image and the physical dimension on the phantom were in good agreement. Point dose verification for a 10 cm × 10 cm beam at a gantry angle of 0° and SAD of 100 cm were performed for a 6 MV beam for both kV and MV CBCT images. The point doses were found to vary between ±6.1% of the dose calculated from the kV CT image. The isodose curves for 6 MV for both kV CT and MV CBCT images were within 2% and 3 mm distance-to-agreement. A plan with three beams was performed on MV CBCT, simulating a treatment plan for cancer of the pituitary. The distribution obtained was compared with those corresponding to that obtained using the kV CT. This study has shown that treatment planning with MV cone beam CT images is feasible.
9. The adaptation of megavoltage cone beam CT for use in standard radiotherapy treatment planning
Energy Technology Data Exchange (ETDEWEB)
Thomas, T Hannah Mary; Purnima, S; Ravindran, B Paul [Department of Radiotherapy, Christian Medical College, Vellore (India); Devakumar, D [Department of Nuclear Medicine, Christian Medical College, Vellore (India)], E-mail: [email protected]
2009-04-07
Potential areas where megavoltage computed tomography (MVCT) could be used are second- and third-phase treatment planning in 3D conformal radiotherapy and IMRT, adaptive radiation therapy, single fraction palliative treatment and for the treatment of patients with metal prostheses. A feasibility study was done on using MV cone beam CT (CBCT) images generated by proprietary 3D reconstruction software based on the FDK algorithm for megavoltage treatment planning. The reconstructed images were converted to a DICOM file set. The pixel values of megavoltage cone beam computed tomography (MV CBCT) were rescaled to those of kV CT for use with a treatment planning system. A calibration phantom was designed and developed for verification of geometric accuracy and CT number calibration. The distance measured between two marker points on the CBCT image and the physical dimension on the phantom were in good agreement. Point dose verification for a 10 cm x 10 cm beam at a gantry angle of 0{sup 0} and SAD of 100 cm were performed for a 6 MV beam for both kV and MV CBCT images. The point doses were found to vary between {+-}6.1% of the dose calculated from the kV CT image. The isodose curves for 6 MV for both kV CT and MV CBCT images were within 2% and 3 mm distance-to-agreement. A plan with three beams was performed on MV CBCT, simulating a treatment plan for cancer of the pituitary. The distribution obtained was compared with those corresponding to that obtained using the kV CT. This study has shown that treatment planning with MV cone beam CT images is feasible.
10. A practical approach to assess clinical planning tradeoffs in the design of individualized IMRT treatment plans.
NARCIS (Netherlands)
Monshouwer, R.; Hoffmann, A.L.; Kunze-Busch, M.C.; Bussink, J.; Kaanders, J.H.A.M.; Huizenga, H.
2010-01-01
BACKGROUND AND PURPOSE: To investigate the tradeoffs between organ at risk sparing and tumour coverage for IMRT treatment of lung tumours, and to develop a tool for clinical use to graphically represent these tradeoffs. MATERIAL AND METHODS: For 5 patients with inoperable non-small cell lung cancer
11. Use of Positron Emission Tomography/Computed Tomography in Radiation Treatment Planning for Lung Cancer
OpenAIRE
Kezban Berberoğlu
2016-01-01
Radiotherapy (RT) plays an important role in the treatment of lung cancer. Accurate diagnosis and staging are crucial in the delivery of RT with curative intent. Target miss can be prevented by accurate determination of tumor contours during RT planning. Currently, tumor contours are determined manually by computed tomography (CT) during RT planning. This method leads to differences in delineation of tumor volume between users. Given the change in RT tools and methods due to rapidly ...
12. An optimisation approach for fuel treatment planning to break the connectivity of high-risk regions
OpenAIRE
Rachmawati, Ramya; Ozlen, Melih; Karin J. Reinke; Hearne, John W.
2015-01-01
Uncontrolled wildfires can lead to loss of life and property and destruction of natural resources. At the same time, fire plays a vital role in restoring ecological balance in many ecosystems. Fuel management, or treatment planning by way of planned burning, is an important tool used in many countries where fire is a major ecosystem process. In this paper, we propose an approach to reduce the spatial connectivity of fuel hazards while still considering the ecological fire requirements of the ...
13. Evaluation of the material assignment method used by a Monte Carlo treatment planning system.
Science.gov (United States)
Isambert, A; Brualla, L; Lefkopoulos, D
2009-12-01
An evaluation of the conversion process from Hounsfield units (HU) to material composition in computerised tomography (CT) images, employed by the Monte Carlo based treatment planning system ISOgray (DOSIsoft), is presented. A boundary in the HU for the material conversion between "air" and "lung" materials was determined based on a study using 22 patients. The dosimetric consequence of the new boundary was quantitatively evaluated for a lung patient plan.
14. The use of proton radiography to reduce uncertainties in proton treatment planning
OpenAIRE
Doolan, P. J.
2015-01-01
The availability and demand for proton therapy is rapidly expanding across the globe. One of the key decisions that must be made in the procurement process by all new centres is which proton treatment planning system (TPS) to purchase. The first topic of this thesis is therefore to evaluate the performance of three different proton TPSs in the planning of ten meningioma patients. The comparison is built upwards from the beam commissioning and attempts are made to make as many variables as pos...
15. TH-A-9A-04: Incorporating Liver Functionality in Radiation Therapy Treatment Planning
Energy Technology Data Exchange (ETDEWEB)
Wu, V; Epelman, M; Feng, M; Cao, Y; Wang, H; Romeijn, E; Matuszak, M [University of Michigan, Ann Arbor, MI (United States)
2014-06-15
Purpose: Liver SBRT patients have both variable pretreatment liver function (e.g., due to degree of cirrhosis and/or prior treatments) and sensitivity to radiation, leading to high variability in potential liver toxicity with similar doses. This work aims to explicitly incorporate liver perfusion into treatment planning to redistribute dose to preserve well-functioning areas without compromising target coverage. Methods: Voxel-based liver perfusion, a measure of functionality, was computed from dynamic contrast-enhanced MRI. Two optimization models with different cost functions subject to the same dose constraints (e.g., minimum target EUD and maximum critical structure EUDs) were compared. The cost functions minimized were EUD (standard model) and functionality-weighted EUD (functional model) to the liver. The resulting treatment plans delivering the same target EUD were compared with respect to their DVHs, their dose wash difference, the average dose delivered to voxels of a particular perfusion level, and change in number of high-/low-functioning voxels receiving a particular dose. Two-dimensional synthetic and three-dimensional clinical examples were studied. Results: The DVHs of all structures of plans from each model were comparable. In contrast, in plans obtained with the functional model, the average dose delivered to high-/low-functioning voxels was lower/higher than in plans obtained with its standard counterpart. The number of high-/low-functioning voxels receiving high/low dose was lower in the plans that considered perfusion in the cost function than in the plans that did not. Redistribution of dose can be observed in the dose wash differences. Conclusion: Liver perfusion can be used during treatment planning potentially to minimize the risk of toxicity during liver SBRT, resulting in better global liver function. The functional model redistributes dose in the standard model from higher to lower functioning voxels, while achieving the same target EUD
16. A dose homogeneity and conformity evaluation between ViewRay and pinnacle-based linear accelerator IMRT treatment plans.
Science.gov (United States)
Saenz, Daniel L; Paliwal, Bhudatt R; Bayouth, John E
2014-04-01
ViewRay, a novel technology providing soft-tissue imaging during radiotherapy is investigated for treatment planning capabilities assessing treatment plan dose homogeneity and conformity compared with linear accelerator plans. ViewRay offers both adaptive radiotherapy and image guidance. The combination of cobalt-60 (Co-60) with 0.35 Tesla magnetic resonance imaging (MRI) allows for magnetic resonance (MR)-guided intensity-modulated radiation therapy (IMRT) delivery with multiple beams. This study investigated head and neck, lung, and prostate treatment plans to understand what is possible on ViewRay to narrow focus toward sites with optimal dosimetry. The goal is not to provide a rigorous assessment of planning capabilities, but rather a first order demonstration of ViewRay planning abilities. Images, structure sets, points, and dose from treatment plans created in Pinnacle for patients in our clinic were imported into ViewRay. The same objectives were used to assess plan quality and all critical structures were treated as similarly as possible. Homogeneity index (HI), conformity index (CI), and volume receiving conformity increase for lung. The volume receiving 20% of the prescription dose increased 2-8% for head and neck and up to 4% for lung and prostate. Overall, for head and neck Co-60 ViewRay treatments planned with its Monte Carlo treatment planning software were comparable with 6 MV plans computed with convolution superposition algorithm on Pinnacle treatment planning system.
17. Three-dimensional treatment planning and conformal radiation therapy: preliminary evaluation
International Nuclear Information System (INIS)
Preliminary clinical results are presented for 209 patients with cancer who had treatment planned on our three-dimensional radiation treatment planning (3-D RTP) system and were treated with external beam conformal radiation therapy. Average times (min) for CT volumetric simulation were: 74 without or 84 with contrast material; 36 for contouring of tumor/target volume and 44 for normal anatomy; 78 for treatment planning; 53 for plan evaluation/optimization; and 58 for verification simulation. Average time of daily treatment sessions with 3-D conformal therapy or standard techniques was comparable for brain, head and neck, thoracic, and hepatobiliary tumors (11.8-14 min and 11.5-12.1, respectively). For prostate cancer patients treated with 3-D conformal technique and Cerrobend blocks, mean treatment time was 19 min; with multileaf collimation it was 14 min and with bilateral arc rotation, 9.8 min. Acute toxicity was comparable to or lower than with standard techniques. Sophisticated 3-D RTP and conformal irradiation can be performed in a significant number of patients at a reasonable cost. Further efforts, including dose-escalation studies, are necessary to develop more versatile and efficient 3-D RTP systems and to enhance the cost benefit of this technology in treatment of patients with cancer
18. Guaranteed epsilon-optimal treatment plans with minimum number of beams for stereotactic body radiation therapy
CERN Document Server
Yarmand, Hamed
2013-01-01
Stereotactic body radiotherapy (SBRT) is characterized by delivering a high amount of dose in a short period of time. In SBRT the dose is delivered using open fields (e.g., beam's-eye-view) known as "apertures". Mathematical methods can be used for optimizing treatment planning for delivery of sufficient dose to the cancerous cells while keeping the dose to surrounding organs at risk (OARs) minimal. Two important elements of a treatment plan are quality and delivery time. Quality of a plan is measured based on the target coverage and dose to OARs. Delivery time heavily depends on the number of beams used in the plan since the setup times for different beam directions constitute a large portion of the delivery time. Therefore the ideal plan, in which all potential beams can be used simultaneously, will be associated with a long impractical delivery time. We use the dose to OARs in the ideal plan to find the plan with the minimum number of beams which is guaranteed to be epsilon-optimal (i.e., a predetermined m...
19. Review of 3D image data calibration for heterogeneity correction in proton therapy treatment planning.
Science.gov (United States)
Zhu, Jiahua; Penfold, Scott N
2016-06-01
Correct modelling of the interaction parameters of patient tissues is of vital importance in proton therapy treatment planning because of the large dose gradients associated with the Bragg peak. Different 3D imaging techniques yield different information regarding these interaction parameters. Given the rapidly expanding interest in proton therapy, this review is written to make readers aware of the current challenges in accounting for tissue heterogeneities and the imaging systems that are proposed to tackle these challenges. A summary of the interaction parameters of interest in proton therapy and the current and developmental 3D imaging techniques used in proton therapy treatment planning is given. The different methods to translate the imaging data to the interaction parameters of interest are reviewed and a summary of the implementations in several commercial treatment planning systems is presented. PMID:27115163
20. Women who conceived with infertility treatment were more likely to receive planned cesarean deliveries in Taiwan.
Science.gov (United States)
Chien, Li-Yin; Lee, Yu-Hsiang; Lin, Yu-Hung; Tai, Chen-Jei
2015-06-01
The objective of this study was to examine the effect of conception with infertility treatment on planned cesarean delivery. The participants were from a panel of primiparous pregnant women in northern Taiwan. The data analysis included 771 women with a singleton pregnancy, of whom 160 had a planned cesarean delivery and 611 who had a vaginal delivery. The study women answered structured questionnaires during the second and third trimesters of pregnancy, and at one-month postpartum. Women who conceived with infertility treatment were more likely to have planned cesarean deliveries than women who conceived without it (44.7% versus 18.1%, p maternal age over 35 years, whether they were currently unmarried, selection of time for birth in advance, gestational hypertension, and birthweight maternal age or higher number of morbidities during pregnancy. Counseling for women who conceive with infertility treatments may be needed to decrease unnecessary cesarean deliveries. PMID:25581216
1. Interim Status Closure Plan Open Burning Treatment Unit Technical Area 16-399 Burn Tray
Energy Technology Data Exchange (ETDEWEB)
Vigil-Holterman, Luciana R. [Los Alamos National Laboratory
2012-05-07
This closure plan describes the activities necessary to close one of the interim status hazardous waste open burning treatment units at Technical Area (TA) 16 at the Los Alamos National Laboratory (LANL or the Facility), hereinafter referred to as the 'TA-16-399 Burn Tray' or 'the unit'. The information provided in this closure plan addresses the closure requirements specified in the Code of Federal Regulations (CFR), Title 40, Part 265, Subparts G and P for the thermal treatment units operated at the Facility under the Resource Conservation and Recovery Act (RCRA) and the New Mexico Hazardous Waste Act. Closure of the open burning treatment unit will be completed in accordance with Section 4.1 of this closure plan.
2. Employment of MCNP in the study of TLDS 600 and 700 seeking the implementation of radiation beam characterization of BNCT facility at IEA-R1
International Nuclear Information System (INIS)
Boron Neutron Capture Therapy, BNCT, is a bimodal radiotherapy procedure for cancer treatment. Its useful energy comes from a nuclear reaction driven by impinging thermal neutron upon Boron 10 atoms. A BNCT research facility has been constructed in IPEN at the IEA-R1 reactor, to develop studies in this area. One of its prime experimental parameter is the beam dosimetry which is nowadays made by using activation foils, for neutron measurements, and TLD 400, for gamma dosimetry. For mixed field dosimetry, the International Commission on Radiation Units and Measurements, ICRU, recommends the use of pair of detectors with distinct responses to the field components. The TLD 600/ TLD 700 pair meets this criteria, as the amount of 6Li, a nuclide with high thermal neutron cross section, greatly differs in their composition. This work presents a series of experiments and simulations performed in order to implement the mixed field dosimetry based on the use of TLD 600/TLD 700 pair. It also intended to compare this mixed field dosimetric methodology to the one so far used by the BNCT research group of IPEN. The response of all TLDs were studied under irradiations in different irradiation fields and simulations, underwent by MCNP, were run in order to evaluate the dose contribution from each field component. Series of repeated irradiations under pure gamma field and mixed field neutron/gamma field showed differences in the TLD individual responses which led to the adoption of a Normalization Factor. It has allowed to overcome TLD selection. TLD responses due to different field components and spectra were studied. It has shown to be possible to evaluate the relative gamma/neutron fluxes from the relative responses observed in the two Regions of Interest, ROIs, from TLD 600 and TLD 700. It has also been possible to observe the TLD 700 response to neutron, which leads to a gamma dose overestimation when one follows the ICRU recommended mixed field dosimetric procedure. Dose
3. An integrated Monte Carlo dosimetric verification system for radiotherapy treatment planning
Science.gov (United States)
Yamamoto, T.; Mizowaki, T.; Miyabe, Y.; Takegawa, H.; Narita, Y.; Yano, S.; Nagata, Y.; Teshima, T.; Hiraoka, M.
2007-04-01
An integrated Monte Carlo (MC) dose calculation system, MCRTV (Monte Carlo for radiotherapy treatment plan verification), has been developed for clinical treatment plan verification, especially for routine quality assurance (QA) of intensity-modulated radiotherapy (IMRT) plans. The MCRTV system consists of the EGS4/PRESTA MC codes originally written for particle transport through the accelerator, the multileaf collimator (MLC), and the patient/phantom, which run on a 28-CPU Linux cluster, and the associated software developed for the clinical implementation. MCRTV has an interface with a commercial treatment planning system (TPS) (Eclipse, Varian Medical Systems, Palo Alto, CA, USA) and reads the information needed for MC computation transferred in DICOM-RT format. The key features of MCRTV have been presented in detail in this paper. The phase-space data of our 15 MV photon beam from a Varian Clinac 2300C/D have been developed and several benchmarks have been performed under homogeneous and several inhomogeneous conditions (including water, aluminium, lung and bone media). The MC results agreed with the ionization chamber measurements to within 1% and 2% for homogeneous and inhomogeneous conditions, respectively. The MC calculation for a clinical prostate IMRT treatment plan validated the implementation of the beams and the patient/phantom configuration in MCRTV.
4. The significance of the choice of radiobiological (NTCP) models in treatment plan objective functions
International Nuclear Information System (INIS)
Full text: A Clinician's discrimination between radiation therapy treatment plans is traditionally a subjective process, based on experience and existing protocols. A more objective and quantitative approach to distinguish between treatment plans is to use radiobiological or dosimetric objective functions, based on radiobiological or dosimetric models. The efficacy of models is not well understood, nor is the correlation of the rank of plans resulting from the use of models compared to the traditional subjective approach. One such radiobiological model is the Normal Tissue Complication Probability (NTCP). Dosimetric models or indicators are more accepted in clinical practice. In this study, three radiobiological models, Lyman NTCP, critical volume NTCP and relative seriality NTCP, and three dosimetric models, Mean Lung Dose (MLD) and the Lung volumes irradiated at lOGy (V|0) and 20Gy (V20), were used to rank a series of treatment plans using, harm to normal (Lung) tissue as the objective criterion. None of the models considered in this study showed consistent correlation with the Radiation Oncologists plan ranking. If radiobiological or dosimetric models are to be used in objective functions for lung treatments, based on this study it is recommended that the Lyman NTCP model be used because it will provide most consistency with traditional clinician ranking.
5. Dose distribution transfer from CyberKnife to Varian treatment planning system
Science.gov (United States)
Osewski, W.; Ślosarek, K.; Karaszewska, B.
2014-03-01
The aim of this paper was to introduce one of the options of the locally developed DDcon.exe which gives the possibility to transfer the dose distribution from CyberKnife (Accuray) treatment planning system (CK TPS) to Varian treatment planning system (Eclipse TPS, Varian). DICOM format is known as a universal format for medical data. The dose distribution is stored as RTdose file in DICOM format, so there should be a possibility to transfer it between different treatment planning systems. Trying to transfer RTdose file from CK TPS to Eclipse TPS the error message occurs. That's because the RTdose file in CK TPS is connected with Structure_Set_Sequence against Eclipse TPS where it's connected with RT_Plan_Sequence. To make it transferable RTdose file from CK TPS have to be 'disconnected' from Structure_Set_Sequence and 'connected' with RT_Plan_Sequence. This is possible thanks DDcon software which creates new RTdose file by changing proper DICOM tags in original RTdose file. New homemade software gives us an opportunity to transfer dose distribution from CyberKnife TPS to TPS Eclipse. This method opens new possibilities to combine or compare different treatment techniques in Varian TPS.
6. Comparison of the dose to lung volume between supine and prone position during treatment planning
Institute of Scientific and Technical Information of China (English)
Yu Li; Huijun Xu ; Sujing Zhang; Xiaoliang Liu
2015-01-01
Objective The aim of the study was to compare the dose to lung volume in the supine and prone posi-tion while designing CyberKnife treatment plans to treat metastatic tumors in the spinous processes of the thoracic vertebrae, and of er a reference for reducing damage to normal tissues. Methods Nine cases of metastatic tumors in the spinous processes of the thoracic vertebrae were se-lected, and then we designed treatment plans based on the supine and prone positions and compared the results. Results In contrast with the treatment plan based on the prone position, the one for the supine position required 14862–36337 MU more; the lung D5% was 5.20–7.90 Gy higher; and the lung D20% was 2.61–5.73 Gy higher. The dif erence of dose to spine volume between the two plans was –2.21–2.67 Gy; to the skin volume was –3.93–7.85 Gy; and to the esophagus was 0.28–6.39 Gy. Conclusion The treatment plan based on the prone position of patients can better protect lung tissues than the one based on the supine position, and can also improve the availability of beams.
7. The feasibility of using Pareto fronts for comparison of treatment planning systems and delivery techniques.
Science.gov (United States)
Ottosson, Rickard O; Engstrom, Per E; Sjöström, David; Behrens, Claus F; Karlsson, Anna; Knöös, Tommy; Ceberg, Crister
2009-01-01
Pareto optimality is a concept that formalises the trade-off between a given set of mutually contradicting objectives. A solution is said to be Pareto optimal when it is not possible to improve one objective without deteriorating at least one of the other. A set of Pareto optimal solutions constitute the Pareto front. The Pareto concept applies well to the inverse planning process, which involves inherently contradictory objectives, high and uniform target dose on one hand, and sparing of surrounding tissue and nearby organs at risk (OAR) on the other. Due to the specific characteristics of a treatment planning system (TPS), treatment strategy or delivery technique, Pareto fronts for a given case are likely to differ. The aim of this study was to investigate the feasibility of using Pareto fronts as a comparative tool for TPSs, treatment strategies and delivery techniques. In order to sample Pareto fronts, multiple treatment plans with varying target conformity and dose sparing of OAR were created for a number of prostate and head & neck IMRT cases. The DVHs of each plan were evaluated with respect to target coverage and dose to relevant OAR. Pareto fronts were successfully created for all studied cases. The results did indeed follow the definition of the Pareto concept, i.e. dose sparing of the OAR could not be improved without target coverage being impaired or vice versa. Furthermore, various treatment techniques resulted in distinguished and well separated Pareto fronts. Pareto fronts may be used to evaluate a number of parameters within radiotherapy. Examples are TPS optimization algorithms, the variation between accelerators or delivery techniques and the degradation of a plan during the treatment planning process. The issue of designing a model for unbiased comparison of parameters with such large inherent discrepancies, e.g. different TPSs, is problematic and should be carefully considered.
8. Automated gamma knife radiosurgery treatment planning with image registration, data-mining, and Nelder-Mead simplex optimization
International Nuclear Information System (INIS)
Gamma knife treatments are usually planned manually, requiring much expertise and time. We describe a new, fully automatic method of treatment planning. The treatment volume to be planned is first compared with a database of past treatments to find volumes closely matching in size and shape. The treatment parameters of the closest matches are used as starting points for the new treatment plan. Further optimization is performed with the Nelder-Mead simplex method: the coordinates and weight of the isocenters are allowed to vary until a maximally conformal plan specific to the new treatment volume is found. The method was tested on a randomly selected set of 10 acoustic neuromas and 10 meningiomas. Typically, matching a new volume took under 30 seconds. The time for simplex optimization, on a 3 GHz Xeon processor, ranged from under a minute for small volumes (30 000 cubic mm,>20 isocenters). In 8/10 acoustic neuromas and 8/10 meningiomas, the automatic method found plans with conformation number equal or better than that of the manual plan. In 4/10 acoustic neuromas and 5/10 meningiomas, both overtreatment and undertreatment ratios were equal or better in automated plans. In conclusion, data-mining of past treatments can be used to derive starting parameters for treatment planning. These parameters can then be computer optimized to give good plans automatically
9. Water: from the source to the treatment plan
Science.gov (United States)
Marquet, V.; Baude, I.
2012-04-01
As a biology and geology teacher, I have worked on water, from the source to the treatment plant, with pupils between 14 and 15 years old. Lesson 1. Introduction, the water in Vienna Aim: The pupils have to consider why the water is so important in Vienna (history, economy etc.) Activities: Brainstorming about where and why we use water every day and why the water is different in Vienna. Lesson 2. Soil, rock and water Aim: Permeability/ impermeability of the different layers of earth Activities: The pupils have measure the permeability and porosity of different stones: granite, clay, sand, carbonate and basalt. Lesson 3. Relationship between water's ion composition and the stone's mineralogy Aim: Each water source has the same ion composition as the soil where the water comes from. Activities: Comparison between the stone's mineralogy and ions in water. They had a diagram with the ions of granite, clay, sand, carbonate and basalt and the label of different water. They had to make hypotheses about the type of soil where the water came from. They verified this with a geology map of France and Austria. They have to make a profile of the area where the water comes from. They had to confirm or reject their hypothesis. Lesson 4 .Water-catchment and reservoir rocks Aim: Construction of a confined aquifer and artesian well Activities: With sand, clay and a basin, they have to model a confined aquifer and make an artesian well, using what they have learned in lesson 2. Lesson 5. Organic material breakdown and it's affect on the oxygen levels in an aquatic ecosystem Aim: Evaluate the relationship between oxygen levels and the amount of organic matter in an aquatic ecosystem. Explain the relationship between oxygen levels, bacteria and the breakdown of organic matter using an indicator solution. Activities: Put 5 ml of a different water sample in each tube with 20 drops of methylene blue. Observe the tubes after 1 month. Lesson 6. Visit to the biggest water treatment plant in
10. A treatment planning approach to spatially fractionated megavoltage grid therapy for bulky lung cancer
Energy Technology Data Exchange (ETDEWEB)
Costlow, Heather N. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States); Zhang, Hualin, E-mail: [email protected] [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States); Department of Radiation Oncology, Northwestern University Feinberg School of Medicine, Northwestern University, Northwestern Memorial Hospital, Chicago, IL (United States); Das, Indra J. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States)
2014-10-01
The purpose of this study was to explore the treatment planning methods of spatially fractionated megavoltage grid therapy for treating bulky lung tumors using multileaf collimator (MLC). A total of 5 patients with lung cancer who had gross tumor volumes ranging from 277 to 635 cm{sup 3} were retrospectively chosen for this study. The tumors were from 6.5 to 9.6 cm at shortest dimension. Several techniques using either electronic compensation or intensity-modulated radiation therapy (IMRT) were used to create a variety of grid therapy plans on the Eclipse treatment planning system. The dose prescription point was calculated to the volume, and a dose of 20 Gy with 6-MV/15-MV beams was used in each plan. The dose-volume histogram (DVH) curves were obtained to evaluate dosimetric characteristics. In addition, DVH curves from a commercially available cerrobend grid collimator were also used for comparison. The linear-quadratic radiobiological response model was used to assess therapeutic ratios (TRs) and equivalent uniform doses (EUD) for all generated plans. A total of 6 different grid therapy plans were created for each patient. Overall, 4 plans had different electronic compensation techniques: Ecomps-Tubes, Ecomps-Circles, Ecomps-Squares, and Ecomps-Weave; the other 2 plans used IMRT and IMRT-Weave techniques. The DVH curves and TRs demonstrated that these MLC-based grid therapy plans can achieve dosimetric properties very similar to those of the cerrobend grid collimator. However, the MLC-based plans have larger EUDs than those with the cerrobend grid collimator. In addition, the field shaping can be performed for targets of any shape in MLC-based plans. Thus, they can deliver a more conformal dose to the targets and spare normal structures better than the cerrobend grid collimator can. The plans generated by the MLC technique demonstrated the advantage over the standard cerrobend grid collimator on accommodating targets and sparing normal structures. Overall, 6
11. Dosimetric evaluation of two treatment planning systems for high dose rate brachytherapy applications
Energy Technology Data Exchange (ETDEWEB)
Shwetha, Bondel [Department of Radiation Physics, Kidwai, Memorial Institute of Oncology, Bangalore (India); Ravikumar, Manickam, E-mail: [email protected] [Department of Radiation Physics, Kidwai, Memorial Institute of Oncology, Bangalore (India); Supe, Sanjay S.; Sathiyan, Saminathan [Department of Radiation Physics, Kidwai, Memorial Institute of Oncology, Bangalore (India); Lokesh, Vishwanath [Department of Radiotherapy, Kidwai, Memorial Institute of Oncology, Bangalore (India); Keshava, Subbarao L. [Department of Radiation Physics, Kidwai, Memorial Institute of Oncology, Bangalore (India)
2012-04-01
Various treatment planning systems are used to design plans for the treatment of cervical cancer using high-dose-rate brachytherapy. The purpose of this study was to make a dosimetric comparison of the 2 treatment planning systems from Varian medical systems, namely ABACUS and BrachyVision. The dose distribution of Ir-192 source generated with a single dwell position was compared using ABACUS (version 3.1) and BrachyVision (version 6.5) planning systems. Ten patients with intracavitary applications were planned on both systems using orthogonal radiographs. Doses were calculated at the prescription points (point A, right and left) and reference points RU, LU, RM, LM, bladder, and rectum. For single dwell position, little difference was observed in the doses to points along the perpendicular bisector. The mean difference between ABACUS and BrachyVision for these points was 1.88%. The mean difference in the dose calculated toward the distal end of the cable by ABACUS and BrachyVision was 3.78%, whereas along the proximal end the difference was 19.82%. For the patient case there was approximately 2% difference between ABACUS and BrachyVision planning for dose to the prescription points. The dose difference for the reference points ranged from 0.4-1.5%. For bladder and rectum, the differences were 5.2% and 13.5%, respectively. The dose difference between the rectum points was statistically significant. There is considerable difference between the dose calculations performed by the 2 treatment planning systems. It is seen that these discrepancies are caused by the differences in the calculation methodology adopted by the 2 systems.
12. Dosimetric evaluation of two treatment planning systems for high dose rate brachytherapy applications.
Science.gov (United States)
Shwetha, Bondel; Ravikumar, Manickam; Supe, Sanjay S; Sathiyan, Saminathan; Lokesh, Vishwanath; Keshava, Subbarao L
2012-01-01
Various treatment planning systems are used to design plans for the treatment of cervical cancer using high-dose-rate brachytherapy. The purpose of this study was to make a dosimetric comparison of the 2 treatment planning systems from Varian medical systems, namely ABACUS and BrachyVision. The dose distribution of Ir-192 source generated with a single dwell position was compared using ABACUS (version 3.1) and BrachyVision (version 6.5) planning systems. Ten patients with intracavitary applications were planned on both systems using orthogonal radiographs. Doses were calculated at the prescription points (point A, right and left) and reference points RU, LU, RM, LM, bladder, and rectum. For single dwell position, little difference was observed in the doses to points along the perpendicular bisector. The mean difference between ABACUS and BrachyVision for these points was 1.88%. The mean difference in the dose calculated toward the distal end of the cable by ABACUS and BrachyVision was 3.78%, whereas along the proximal end the difference was 19.82%. For the patient case there was approximately 2% difference between ABACUS and BrachyVision planning for dose to the prescription points. The dose difference for the reference points ranged from 0.4-1.5%. For bladder and rectum, the differences were 5.2% and 13.5%, respectively. The dose difference between the rectum points was statistically significant. There is considerable difference between the dose calculations performed by the 2 treatment planning systems. It is seen that these discrepancies are caused by the differences in the calculation methodology adopted by the 2 systems.
13. Reassessment of the laparoscopy role in the investigation of infertility and treatment plan determination
Institute of Scientific and Technical Information of China (English)
Sebastio F de Medeiros; Mrcia MW Yamamoto; Bianca B Galera; Matheus AS de Medeiros; Jacklyne S Barbosa
2012-01-01
Objective:To reassess the importance of laparoscopy in infertility investigation treatment plan determination.Methods:The study enrolled237 patients with infertility duration >1 year.A complete investigation was performed in all patients and male factor was evaluated by medical history and semen analysis.In the case of normal semen or mild-to-moderate oligozoospermia, the female evaluation included screening for infection diseases, transvaginal ultrasound, hormone parameter, hysterosalpingography, and laparoscopy.The final treatment plan was decided according to laparoscopy findings and any modification of the initial proposal was taken as treatment change. Results:At laparoscopy, normal pelvic cavity was found in5.5%, endometriosis in76.4%, pelvic adhesion in17.2%, ovarian adhesion in24.8%, peritubal adhesion 15.2%, unilateral tubal occlusion in21.1%, bilateral tubal occlusion in5.5%, and tubal sacculation, kinking, constriction, or fibrosis in46.3%.Operative interventions during laparoscopy were endometriosis ablation/excision(74.6%), adhesiolysis(27.4%), and endometrioma cystectomy(4.6%). Laparoscopy determined to switch the initial treatment plan in85(35.8%) patients.Conclusions:Pelvic cavity abnormalities, primarily endometriosis, have high prevalence in infertileBrazilian women.Laparoscopy provides a precise diagnosis of tuboperitoneal factor and may switch the initial treatment plan in at least one third of patients.
14. Patient specific optimization-based treatment planning for catheter-based ultrasound hyperthermia and thermal ablation
Science.gov (United States)
Prakash, Punit; Chen, Xin; Wootton, Jeffery; Pouliot, Jean; Hsu, I.-Chow; Diederich, Chris J.
2009-02-01
A 3D optimization-based thermal treatment planning platform has been developed for the application of catheter-based ultrasound hyperthermia in conjunction with high dose rate (HDR) brachytherapy for treating advanced pelvic tumors. Optimal selection of applied power levels to each independently controlled transducer segment can be used to conform and maximize therapeutic heating and thermal dose coverage to the target region, providing significant advantages over current hyperthermia technology and improving treatment response. Critical anatomic structures, clinical target outlines, and implant/applicator geometries were acquired from sequential multi-slice 2D images obtained from HDR treatment planning and used to reconstruct patient specific 3D biothermal models. A constrained optimization algorithm was devised and integrated within a finite element thermal solver to determine a priori the optimal applied power levels and the resulting 3D temperature distributions such that therapeutic heating is maximized within the target, while placing constraints on maximum tissue temperature and thermal exposure of surrounding non-targeted tissue. This optimizationbased treatment planning and modeling system was applied on representative cases of clinical implants for HDR treatment of cervix and prostate to evaluate the utility of this planning approach. The planning provided significant improvement in achievable temperature distributions for all cases, with substantial increase in T90 and thermal dose (CEM43T90) coverage to the hyperthermia target volume while decreasing maximum treatment temperature and reducing thermal dose exposure to surrounding non-targeted tissues and thermally sensitive rectum and bladder. This optimization based treatment planning platform with catheter-based ultrasound applicators is a useful tool that has potential to significantly improve the delivery of hyperthermia in conjunction with HDR brachytherapy. The planning platform has been extended
15. The hamster cheek pouch (HCP) as an experimental model of oral cancer for BNCT: biodistribution and pharmacokinetics of BPA
Energy Technology Data Exchange (ETDEWEB)
Kreimann, E.; Itoiz, M.E.; Dagrosa, A.; Garavaglia, R.; Farias, S.; Batistoni, D.; Schwint, A.E. [National Atomic Energy Commission (Argentina)
2000-10-01
We propose and validate the HCP model of oral cancer for BNCT studies. This model serves to explore new applications of the technique, study the biology of BNCT and assess Boron uptake in clinically relevant oral tissues. Tumors are induced by a process that mimics spontaneous malignant transformation instead of by the growth of implanted tumor cells. Syrian hamsters were submitted to tumor induction with a chemical carcinogenesis protocol and then used for biodistribution and pharmacokinetic studies of BPA. The data reveal selective uptake by tumor and, to a lesser degree, by precancerous tissue. Boron concentration in oral tissues and skin was higher than in blood, an issue of clinical relevance given that these tissues may be dose-limiting. Absolute and relative values of Boron concentration would be potentially therapeutic. Boron concentration exhibited a linear relationship with percentage of viable tissue in HCP tumors. The HCP model would provide a novel, contributory approach to BNCT research. (author)
16. The hamster cheek pouch (HCP) as an experimental model of oral cancer for BNCT: biodistribution and pharmacokinetics of BPA
International Nuclear Information System (INIS)
We propose and validate the HCP model of oral cancer for BNCT studies. This model serves to explore new applications of the technique, study the biology of BNCT and assess Boron uptake in clinically relevant oral tissues. Tumors are induced by a process that mimics spontaneous malignant transformation instead of by the growth of implanted tumor cells. Syrian hamsters were submitted to tumor induction with a chemical carcinogenesis protocol and then used for biodistribution and pharmacokinetic studies of BPA. The data reveal selective uptake by tumor and, to a lesser degree, by precancerous tissue. Boron concentration in oral tissues and skin was higher than in blood, an issue of clinical relevance given that these tissues may be dose-limiting. Absolute and relative values of Boron concentration would be potentially therapeutic. Boron concentration exhibited a linear relationship with percentage of viable tissue in HCP tumors. The HCP model would provide a novel, contributory approach to BNCT research. (author)
17. Treatment Planning to Improve Delivery Accuracy and Patient Throughput in Helical Tomotherapy
International Nuclear Information System (INIS)
Purpose: To investigate delivery quality assurance (DQA) discrepancies observed for a subset of helical tomotherapy patients. Methods and Materials: Six tomotherapy patient plans were selected for analysis. Three had passing DQA ion chamber (IC) measurements, whereas 3 had measurements deviating from the expected dose by more than 3.0%. All plans used similar parameters, including: 2.5 cm field-width, 15-s gantry period, and pitch values ranging from 0.143 to 0.215. Preliminary analysis suggested discrepancies were associated with plans having predominantly small leaf open times (LOTs). To test this, patients with failing DQA measurements were replanned using an increased pitch of 0.287. New DQA plans were generated and IC measurements performed. Exit fluence data were also collected during DQA delivery for dose reconstruction purposes. Results: Sinogram analysis showed increases in mean LOTs ranging from 29.8% to 83.1% for the increased pitch replans. IC measurements for these plans showed a reduction in dose discrepancies, bringing all measurements within ±3.0%. The replans were also more efficient to deliver, resulting in reduced treatment times. Dose reconstruction results were in excellent agreement with IC measurements, illustrating the impact of leaf-timing inaccuracies on plans having predominantly small LOTs. Conclusions: The impact of leaf-timing inaccuracies on plans with small mean LOTs can be considerable. These inaccuracies result from deviations in multileaf collimator latency from the linear approximation used by the treatment planning system and can be important for plans having a 15-s gantry period. The ability to reduce this effect while improving delivery efficiency by increasing the pitch is demonstrated.
18. Benchmarking of a treatment planning system for spot scanning proton therapy: Comparison and analysis of robustness to setup errors of photon IMRT and proton SFUD treatment plans of base of skull meningioma
Energy Technology Data Exchange (ETDEWEB)
Harding, R., E-mail: [email protected] [St James’s Institute of Oncology, Medical Physics and Engineering, Leeds LS9 7TF, United Kingdomand Abertawe Bro Morgannwg University Health Board, Medical Physics and Clinical Engineering, Swansea SA2 8QA (United Kingdom); Trnková, P.; Lomax, A. J. [Paul Scherrer Institute, Centre for Proton Therapy, Villigen 5232 (Switzerland); Weston, S. J.; Lilley, J.; Thompson, C. M.; Cosgrove, V. P. [St James’s Institute of Oncology, Medical Physics and Engineering, Leeds LS9 7TF (United Kingdom); Short, S. C. [Leeds Institute of Molecular Medicine, Oncology and Clinical Research, Leeds LS9 7TF, United Kingdomand St James’s Institute of Oncology, Oncology, Leeds LS9 7TF (United Kingdom); Loughrey, C. [St James’s Institute of Oncology, Oncology, Leeds LS9 7TF (United Kingdom); Thwaites, D. I. [St James’s Institute of Oncology, Medical Physics and Engineering, Leeds LS9 7TF, United Kingdomand Institute of Medical Physics, School of Physics, University of Sydney, Sydney NSW 2006 (Australia)
2014-11-01
Purpose: Base of skull meningioma can be treated with both intensity modulated radiation therapy (IMRT) and spot scanned proton therapy (PT). One of the main benefits of PT is better sparing of organs at risk, but due to the physical and dosimetric characteristics of protons, spot scanned PT can be more sensitive to the uncertainties encountered in the treatment process compared with photon treatment. Therefore, robustness analysis should be part of a comprehensive comparison between these two treatment methods in order to quantify and understand the sensitivity of the treatment techniques to uncertainties. The aim of this work was to benchmark a spot scanning treatment planning system for planning of base of skull meningioma and to compare the created plans and analyze their robustness to setup errors against the IMRT technique. Methods: Plans were produced for three base of skull meningioma cases: IMRT planned with a commercial TPS [Monaco (Elekta AB, Sweden)]; single field uniform dose (SFUD) spot scanning PT produced with an in-house TPS (PSI-plan); and SFUD spot scanning PT plan created with a commercial TPS [XiO (Elekta AB, Sweden)]. A tool for evaluating robustness to random setup errors was created and, for each plan, both a dosimetric evaluation and a robustness analysis to setup errors were performed. Results: It was possible to create clinically acceptable treatment plans for spot scanning proton therapy of meningioma with a commercially available TPS. However, since each treatment planning system uses different methods, this comparison showed different dosimetric results as well as different sensitivities to setup uncertainties. The results confirmed the necessity of an analysis tool for assessing plan robustness to provide a fair comparison of photon and proton plans. Conclusions: Robustness analysis is a critical part of plan evaluation when comparing IMRT plans with spot scanned proton therapy plans.
19. Registration of CT to pre-treatment MRI for planning of MR-HIFU ablation treatment of painful bone metastases
International Nuclear Information System (INIS)
MR-HIFU is a new non-invasive treatment modality that can be used for palliation in patients with painful bone metastases. Since treatment strategies are mainly focused on the ablation of periosteal nerves, information on the presence and geometry of cortical bone influences the treatment strategy, both in determining the acoustic power and in avoiding safety issues related to far-field heating. Although MRI is available for imaging during treatment, CT is best used for examining the cortical bone. We present a registration method for registering CT and MR images of patients with bone metastases prior to therapy. CT and MRI data were obtained from nine patients with metastatic bone lesions at varying locations. A two-step registration approach was used, performing simultaneous rigid registration of all available MR images in the first step and an affine and deformable registration with an additional bone metric in the second step. The performance was evaluated using landmark annotation by clinical observers. An average registration error of 4.5 mm was obtained, which was comparable to the slice thickness of the data. The performance of the registration algorithm was satisfactory, even with differences in MRI acquisition parameters and for various anatomical sites. The obtained CT overlay is useful for treatment planning, as it allows an assessment of the integrity of the cortical bone. CT-MR registration is therefore recommended for HIFU treatment planning of patients with bone metastases. (paper)
20. Registration of CT to pre-treatment MRI for planning of MR-HIFU ablation treatment of painful bone metastases
Science.gov (United States)
Noorda, Yolanda H.; Bartels, Lambertus W.; Huisman, Merel; Nijenhuis, Robbert J.; AAJ van den Bosch, Maurice; Pluim, Josien PW
2014-08-01
MR-HIFU is a new non-invasive treatment modality that can be used for palliation in patients with painful bone metastases. Since treatment strategies are mainly focused on the ablation of periosteal nerves, information on the presence and geometry of cortical bone influences the treatment strategy, both in determining the acoustic power and in avoiding safety issues related to far-field heating. Although MRI is available for imaging during treatment, CT is best used for examining the cortical bone. We present a registration method for registering CT and MR images of patients with bone metastases prior to therapy. CT and MRI data were obtained from nine patients with metastatic bone lesions at varying locations. A two-step registration approach was used, performing simultaneous rigid registration of all available MR images in the first step and an affine and deformable registration with an additional bone metric in the second step. The performance was evaluated using landmark annotation by clinical observers. An average registration error of 4.5 mm was obtained, which was comparable to the slice thickness of the data. The performance of the registration algorithm was satisfactory, even with differences in MRI acquisition parameters and for various anatomical sites. The obtained CT overlay is useful for treatment planning, as it allows an assessment of the integrity of the cortical bone. CT-MR registration is therefore recommended for HIFU treatment planning of patients with bone metastases.
1. A plan analysis of pedophile sexual abusers' motivations for treatment: a qualitative pilot study.
Science.gov (United States)
Drapeau, Martin; Körner, Annett; Granger, Luc; Brunet, Louis; Caspar, Franz
2005-06-01
Many authors have suggested adapting treatment programs to the specific needs of sexual abusers. However, little research has been conducted to understand what these patients seek in therapy or what elements play a key role in keeping them in treatment. In this pilot study, fifteen (N=15) pedophile sexual abusers from La Macaza clinic for sexual abusers were interviewed. Plan analysis was used to investigate the most prevalent components involved in staying in or leaving therapy. Results suggest that many components involved in the plans leading to doing and to avoiding treatment were similar. Differences were found in regards to the outcome of confrontations with the therapists, a tendency to isol
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https://homework.cpm.org/category/CON_FOUND/textbook/ac/chapter/14/lesson/14.2.1.7/problem/2-104
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### Home > AC > Chapter 14 > Lesson 14.2.1.7 > Problem2-104
2-104.
The general equation for an aritmetic sequence is t(n) = mn + b.
Use t(8) = 1056 to write an equation.
t(8) = m(8) + b or 1056 = 8m + b
Use t(13) = 116 to write another equation.
Solve the system of equations you wrote for m and b.
t(n) = −188n + 2560
To find t(5), substitute 5 for n in the equation that you wrote.
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https://www.aimsciences.org/article/doi/10.3934/mcrf.2021012
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# American Institute of Mathematical Sciences
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Optimal control of a non-smooth quasilinear elliptic equation
September 2021, 11(3): 555-578. doi: 10.3934/mcrf.2021012
## Optimal control of ODEs with state suprema
1 Institute of Mathematics, University of Würzburg, Emil-Fischer-Str. 40, 97074 Würzburg, Germany 2 Brandenburgische Technische Universität Cottbus-Senftenberg, Institute of Mathematics, 03046 Cottbus, Germany
* Corresponding author: D. Wachsmuth
Received May 2019 Revised November 2019 Published September 2021 Early access March 2021
Fund Project: The second and third author were supported by DFG grants within the Priority Program SPP 1962 (Non-smooth and Complementarity-based Distributed Parameter Systems: Simulation and Hierarchical Optimization), which is gratefully acknowledged
We consider the optimal control of a differential equation that involves the suprema of the state over some part of the history. In many applications, this non-smooth functional dependence is crucial for the successful modeling of real-world phenomena. We prove the existence of solutions and show that related problems may not possess optimal controls. Due to the non-smoothness in the state equation, we cannot obtain optimality conditions via standard theory. Therefore, we regularize the problem via a LogIntExp functional which generalizes the well-known LogSumExp. By passing to the limit with the regularization, we obtain an optimality system for the original problem. The theory is illustrated by some numerical experiments.
Citation: Tobias Geiger, Daniel Wachsmuth, Gerd Wachsmuth. Optimal control of ODEs with state suprema. Mathematical Control & Related Fields, 2021, 11 (3) : 555-578. doi: 10.3934/mcrf.2021012
##### References:
show all references
##### References:
Plots for control $u$, state $x$, adjoint $\lambda$ and its time derivative $\mathrm{d}\lambda$
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2020 Impact Factor: 1.284
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https://getrevising.co.uk/revision-tests/kinetics-9
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Kinetics
HideShow resource information
• Created by: r98
• Created on: 19-03-16 12:34
What are the main factors that affect the rate of reactions?
Temperature, concentration, pressure, surface area and catalysts.
1 of 17
What's the definition of rate of reaction?
The change in concentration (of any of the reactants or products) with unit time.
2 of 17
How do you find the rate at a particular instant?
Draw a tangent to the curve at that time and then find its gradient (slope).
3 of 17
Why do we have to keep the temperature constant when measuring rate of reaction?
Because rate varies with temperature.
4 of 17
What are the units of reaction rates?
mol dm-3 s-1
5 of 17
Can a species thats not in the chemical equation appear in the rate equation?
Yes, for example a catalyst.
6 of 17
Is the rate constant, k, different for every reaction?
Yes.
7 of 17
What does k vary with?
Temperature.
8 of 17
What happens when all the species in the rate equation are 1 mol dm-3?
The rate of reaction is equal to the value of k.
9 of 17
What's the order of reaction?
The order of reaction, with respect to one species, is the power to which the concentration of that species is raised in the rate expression.
10 of 17
What does the order of reaction tell you?
How the rate depends on the concentration of that species.
11 of 17
Do all species in the chemical equation appear in the rate equation?
No, not necessarily.
12 of 17
Do the coefficience of species in the chemical equation have any importance in the rate expression?
No, they have no relevance.
13 of 17
What are the units of the rate constant, k?
The units of the rate constant vary depending on the overall order of the reaction.
14 of 17
Increasing temperature always increases what two things?
The rate of reaction & the value of the rate constant, k.
15 of 17
Do steps that occur after the rate-determining step affect the rate?
No, provided that it's fast compared with the rate-determining step.
16 of 17
Do species that are involved in the mechanism after the rate-determining step appear in the rate expression?
No, only species involved in or before the rate-determining step could affect the overall rate and therefore appear in the rate expression.
17 of 17
Other cards in this set
Card 2
Front
What's the definition of rate of reaction?
Back
The change in concentration (of any of the reactants or products) with unit time.
Card 3
Front
How do you find the rate at a particular instant?
Card 4
Front
Why do we have to keep the temperature constant when measuring rate of reaction?
Card 5
Front
What are the units of reaction rates?
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http://www.latexmattress.org/types-of-latex/blended-latex.php
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## Natural Latex Production
Natural latex is a thin liquid produced in small quantities by a variety of plant species. A few species, particularly Hevea brasiliensis (the "rubber tree") can produce liquid latex in sufficient quantities for use in industrial production.
Latex grown on rubber tree estates is "tapped" to access the latex, in much the same way as maple trees are "tapped" for maple syrup. After the latex is collected, and while it's still in liquid form, the latex is processed using special molds, temperature control, aeration, and (in some cases) chemical additives. When the liquid latex is processed into thick latex foam with the right specifications, it becomes an excellent premium bedding material.
## Synthetic Latex
It's possible to make synthetic latex in a lab using basic elements and manmade chemical components. But though synthetic latex is often considered premium bedding, no synthetic version can match the natural, responsive resilience of real natural latex.
Some forms of synthetic latex may be longer-lasting than natural latex. But since all-natural latex beds can last 20+ years, and the best ones come with a long-term warranty, it doesn't makes sense to choose the synthetic version on the basis of "shelf life" alone.
## Natural Plus Synthetic: Blended Latex
"Blended latex" literally blends the liquid of natural and synthetic types of latex before the molding process begins. In most cases, blended latex foam is made up of 30% natural latex and 70% synthetic latex.
The natural latex in blended foam gives the larger proportion of synthetic latex something approximating the springy, body-contouring softness of the real thing. A bed with the "blended latex" label is a 100% latex mattress, but don't mistake it for a 100% natural latex mattress.
## Blended Latex and the Talalay Production Process
Usually only latex produced using the Talalay method is blended. The other latex foam production process – Dunlop – tends to create a truly inferior product when a blended mix is used.
Talalay tends to be less dense than Dunlop and thus doesn't hold up as well. Over time, an all-Talalay mattress may sink in on itself, making you uncomfortable at night and shortening its lifespan.
If you choose a mattress that's a blended Talalay, expect to have difficulties with your mattress down the road. Blended Talalay latex, like natural Talalay latex, works best as a "comfort layer" on top of a Dunlop core or a polyurethane core if you're on a budget.
## Blended Latex vs. Natural Latex
Natural latex is expensive for a reason. When you buy all-natural latex, you invest in the hidden costs of transportation, agricultural management, and equipment used in processing. Natural latex is also a truly superior material for ameliorating night time pressure-point related pain and unsatisfying sleep.
The characteristics of natural latex make it superior to blended latex options – but blended latex can approximate many of the advantages of natural latex at a more manageable price.
## Blended Latex Pros
• More affordable than 100% natural latex options.
• Percentage of natural latex in the mix approximates the springy support of real latex.
• Talalay production method makes it a material favored by side sleepers.
## Blended Latex Cons
• Not as long-lasting as all-natural Dunlop latex.
• Talalay production method means blended latex is not recommended for persons who sleep on their backs or prefer a firm mattress.
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Speed Then, she thought to go through her own car. (1) We use a graph paper to draw distance-time graph. These clocks are called quartz clocks. On the other hand, an object moving along a straight line with a constant speed is said to be in uniform motion. In our daily life routine, we usually see some objects at rest and others in motion like birds fly, fish swimming, planets moving around the sun, etc., are all in motion. Scroll down for Motion and Time from NCERT Book Class 7 Science Book & important study material. She has started this educational website with the mindset of spreading Free Education to everyone. For eg, in the above diagram, distance quantity is 10 whereas time quantity is 20. Get Revision Notes of Class 7th Science Chapter 13 Motion and Time to score good marks in your Exams. By drawing the distance-time graph, the motion of an object can be represented in diagram form. Motion and Time. Periodic motion: The motion which repeats itself after regular intervals of time, is called periodic motion, Slow or Fast Motion Next. In this case, the average speed is the same as the actual speed. We can see in the graph that the first reading given in this problem is time = 0 and distance = 0. Science worksheets for class 7 CBSE includes worksheets on Motion and Time as per NCERT syllabus. This observation led to the development of pendulum clocks. About Mrs Shilpi Nagpal. Question 1. (iii) A device which uses the rate at which water drip from one vessel to another measure time interval is known as a water clock. The pendulum also completes one oscillation when its bob moves from one extreme position A to the other extreme position B and comes back to A. A freely falling stone. In this problem, we have only small time values (0, 2, 4, 6, 8 and 10 min) to represent. Odometer: Measures and displays distance travelled by the vehicle. Types of motion on the basis of time frame: There are two types of motion on the basis of time frame. NCERT Solutions for Class 7 Science CBSE, 13 Motion and Time. Free PDF download of Class 7 Science Chapter 13 - Motion and Time Revision Notes & Short Key-notes prepared by expert Science teachers from latest edition of CBSE(NCERT) books. It shows that the car will travel a distance of 50 km in 1 h. It does not matter if a car seldom moves with a constant speed for one hour as it starts moving slowly and then picks up speed. Class 7 Physics Motion and Time. We have provided Revision Notes for Class 7 here that is detailed and cover all the important points. If we have to compare the speeds of a number of objects, then we must express the speeds of all those objects in the same unit. Examples of Curvilinear motion. This instrument tells us the speed of a running vehicle at that instant of time in kilometre per hour. Method to Draw Distance-time Graph If a car travels a distance of 100 km in 2 h, then the speed of this car is given by Position is the location of the object. … NCERT 7th Class (CBSE) Science: Time and Motion – Quiz. Science worksheets for class 7 CBSE includes worksheets on Motion and Time as per NCERT syllabus. This document is highly rated by Class 7 students and has been viewed 56676 times. The pendulum clock uses this periodic motion of pendulum for measuring time.W hen the pendulum swings continuously, its upper end drives some toothed wheels. • Also, slope of the graph calculate the speed of the distance-time graph. Motion and Time Class 7 Science Extra Questions Short Answer Type Questions. Filed Under: Class 7, Motion and Time, Science. Distance=Speed×Time. Determine the maximum quantity to be taken on each axis. Rotational motion: The motion possessed by a body when it spins about a fixed axis, is called rotational motion, In a Distance-Time graph, Distance is considered on the Y-axis (Vertical) and Time is considered on the X-axis (Horizontal). It means that a bicycle takes a longer time than the bus. A motion as you know can be along a straight line, circular or periodic. 1800-212-7858 / 9372462318. Need assistance? Tips, Tricks and Business Ideas. Rectilinear motion: Motion in a straight line. Now, write time (min) on x-axis and distance (km) on the y-axis and also put arrows with them. The second reading is time = 2 min and distance = 2 km. You have already studied about different types of motion in class VI. Therefore, at point O on graph paper, time is 0 and distance is also 0. These class 7 science revision notes can be used by students to skim through the entire syllabus in reduced time easily. So, we put a pencil dot at point A. Motion and Time Part 3 (Motion is relative) Class 7 VII . All the chapter wise questions with solutions to help you to revise the complete CBSE … Nov 09, 2020 - Chapter Notes 1 - Chapter 13 : Motion and Time, Class 7, Science | EduRev Notes is made by best teachers of Class 7. Try to draw the graph so that it covers maximum paper space which will make it look clean. Second is the basic unit (or standard unit) of measuring time and it is represented by symbol s. The larger units of time are minute and hour. Reader Interactions. Take a test on this Chapter Now, you have read the notes on this chapter, take a test to check your understanding of this chapter. Finding speed from distance-time graph • Speed= distance/time = (final position of object – initial position of object)/time taken. Different units of time are used depending on the need, e.g. Reader Interactions. Last Updated on March 20, 2019 By Mrs Shilpi Nagpal 4 Comments. This document is highly rated by Class 7 students and has been viewed 23931 times. or own an. Divide this maximum quantity in smaller equal parts, so that it is easy to mark the points. Speed = $$\frac { Distance travelled }{ Time taken }$$ CBSE Class 7 - Science - CH13 - Motion and Time Motion and Time. If you have any query regarding NCERT Class 7 Science Notes Chapter 13 Motion and Time, drop a comment below and we will get back to you at the earliest. Watch Queue Queue EduRev is like a wikipedia just for education and the Important Points - Motion & Time Class 7 Notes | EduRev images and diagram are … Developer Bytes. For Enquiry. With the help of clocks and watches, we generally Many time measuring devices were used in different parts of the world before the pendulum clocks became popular. To draw a distance-time graph, use a graph paper. In a Distance-Time graph, Distance is considered on the Y-axis (Vertical) and Time is considered on the X-axis (Horizontal). Class 7 Physics Motion and Time. He found that a pendulum of a given length tabes always the same time to complete one oscillation. (i) A sundial measures time by the position of the shadow cast by the sun. The pendulum is said to have completed one oscillation when its bob, starting from its mean position O, moves to A, to B and back to O. Circular motion: The motion possessed by a body when it moves along a circular path, is called circular motion, The metre is the standard unit of distance and second is the standard unit of time. Moreover, m otion and time class 7 notes discuss the effect of motion and speed, Interdependence of Motion, Speed on Time. Rectilinear motion: The motion possessed by the body moving along a straight line path, is called rectilinear motion, Our notes of Chapter 13 Motion and Time are prepared by Maths experts in an easy to remember format, covering all syllabus of CBSE, KVPY, NTSE, Olympiads, NCERT & other Competitive Exams. CBSE worksheets for Motion and Time worksheet for class 7 in PDF for free download. MCQs, NCERT Chapter Solution, Q & A ... Show the shape of the distance-time graph for the motion in the following cases: (i) A car moving with a constant speed. Motion and Time Part 1 (Motion & Examples) Class 7 VII . Free Education for All. The to and fro motion of a simple pendulum is an example of a periodic or an oscillatory motion. Motion. if your school is at a distance of 5 km from your home and you want to go to school by bicycle, then it may take about 25 min to reach the school and if you go to school by school bus, then the same distance can be covered only in 10 min. When a body moves along a curved line, the motion described by the body is called curvilinear motion. The length of a pendulum is the length of thread from the point of suspension to the centre of the bob. The concepts given in the Class 7 will help you in higher classes. CBSE class 7 worksheets as PDF for free download Motion and Time worksheets. In this chapter, you shall learn in detail about types of motion in detail. • The steeper the slope of the graph the more is the speed of object. Physics Motion and Time Part 1 (Motion & Examples) Class 7 VII Compete4Exams. Digital NCERT Books Class 7 Science pdf are always handy to use when you do not have access to physical copy. Usually, a small rectangular window within speedometer dial with the symbol km (as shown in the figure) gives the (metre) odometer reading. e.g. i.e. Speed. (2) The graph paper has 1 centimetre squares marked on it. (3) The side of bigger square on the graph paper is 1 cm and that of the smaller square is 1 mm. Class Notes. Other Types of Graph Class 1-5; Class 6; Class 7; Class 8; Class 9; Class 10; Class 11; Class 12; NCERT Solutions. (4) To draw the distance-time graph for a moving object, we need a graph paper, and the readings of distances travelled by the object and … First read and understand the notes. Speed. A duration or moment in which things occur is known as time. Types of Motion Motion and Time Part 2 (Motion of Pendulum) Class 7 VII . In the same way, metres can be seen on the dashboard of cars, buses and other vehicles in addition to the speedometer, there is another instrument in a vehicle called odometer. Some of the points to be kept in mind while choosing the most suitable scale for drawing a graph are: Slopecalculation using D-T Graph:Slope of a Distance-Time graph (From point A to F) is also the speed at every instant. Again, the distance values given in this problem are small (0, 2, 4, 6, 8 and 10 km). There are four different types of motion shown by the different objects. CBSE Class 7 is one of the crucial stages in students’ academic life. This video is unavailable. Become our . Motion and time class 7 notes are beyond conventional learning. Class 7 Science - Learn Motion and Time: (A) Non-uniform motion and (B) Uniform motion learning video tutorial for CBSE 7th Class students. Topics in this lesson. If object changes its position with the passage of time, it is said to be in motion. We now mark the distance values 0, 2, 4, 6, 8 and 10 on the line OY (see figure). Comments. She has started this educational website with the mindset of spreading Free Education to everyone. Movement of any object from one position to another position with respect to the observer is called as Motion. To register Science Tuitions on Vedantu.com to clear your doubts. The small values of speed are expressed in centimetre per second (cm/s) and in this case, the distance travelled is measured in terms of centimetre and time taken is measured in second. e.g. Motion and Time Class 7 Science Notes - Chapter 13. We generally see while reading newspapers, magazine, etc., that the present information is represented in various forms of graphs in order to make it interesting. Therefore, the speed calculated here is the average speed of the car. Academic Partner. Author of this website, Mrs Shilpi Nagpal is MSc (Hons, Chemistry) and BSc (Hons, Chemistry) from Delhi University, B.Ed (I. P. University) and has many years of experience in teaching. NCERT Solutions for Class 6, 7, 8, 9, 10, 11 and 12. If the speed of an object moving along a straight line beeps changing, its motion is said to be non-uniform motion. Thus, the most convenient way to determine which of the two objects is moving faster is to compare the distance moved by them in a unit time which is known as speed. Speedometer: Measures and displays instantaneous speed of the vehicle. In motion class 9 notes, they are: Uniform Motion; Non-uniform Motion; Uniform Motion: When an object travels equal distances in equal interval of time is said to be uniform motion. Distance-Time Graph. Each centimetre square has 100 smaller squares in it (which are millimetre squares). Last Sunday, Priyanka decided to go outside with her family for the dinner in some particular restaurant. the motion of a child in a merry-go-round, motion of the earth around the sun in a circular orbit. NCERT Solutions for Class 7 Maths Chapter 13 Introduction. Class 7 Science Notes Chapter 13 Motion And Time PDF Download Free. CBSE Maths notes, CBSE physics notes, CBSE chemistry notes NCERT Exemplar Class 7 Science Chapter 13 Motion and Time Solutions CBSETuts.com provides you Free PDF download of NCERT Exemplar Class 7 Science Chapter 13 Motion and Time solved by expert teachers as … The to and fro motion of a simple pendulum is an example of periodic or oscillatory motion. The distance travelled by an object per unit time (either in one hour, in one minute or in one second) is known as speed of the object. Class 7 Motion-Time. This is usually drawn as a line graph as it taken two variable quantities – Distance and Time. Speedometer and Odometer Winding clocks and wristwatches were refinements of the pendulum clocks. A car moving on a straight road. CBSE class 7 worksheets as PDF for free download Motion and Time worksheets. Contact us on below numbers. Motion: Motion means a change in position of an object with respect to time. 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Examples of Rectilinear motion. Oscillation: One complete to and fro motion of a pendulum bob from its mean position. Below is an example of how to prepare a Distance-Time graph based on data. A coin moving over a carom board. So, when we say that the car is moving with a speed of 50 km/h, then we do not bother whether the car has been moving with a constant speed or not during that hour. called a month. A train moving on a straight railway track. 13.1 Slow or Fast An object which takes a long time to cover a certain distance is known as slow while the other object which takes shorter time to cover the same distance is known as fast, e.g. All the solutions of Motion and Time - Science explained in detail by experts to help students prepare for their CBSE exams. Answer: Metre / second is the basic unit of speed. 1 day = 24 h, 1 month = 30 days and 1 year = 12 months. Class 7 students must have the basic understanding of the topics given in NCERT texbook in order to pass exam with flying colors. The distance-time graph for the motion of an object moving with a constant speed is a straight line. they found that the sun rises every day in the morning. Unit of distance is generally measured in units of length like metres, kilometres etc. e.g. Also after the chapter you can get links to Class 7 Science Notes, NCERT Solutions, Important Question, Practice Papers etc. e.g. Note: Nowadays, most clocks or watches have an electric circuit with one or more cells. The speedometer is an instrument on a vehicle’s dashboard which indicates the speed of the vehicle when it is moving. in order to express the longer time interval, the bigger units of time are used, i.e. Displacement is the shortest path covered by the moving object in the given interval of time. Below is a diagram to calculate slope. The motion of all the objects are not of the same type. Non-Uniform and Uniform Motions CBSE Class 7 Science Motion and Time Worksheets with Answers for Chapter 13 in PDF format to download prepared by expert Science teachers from latest edition of CBSE(NCERT) books. In a similar manner, time from one full moon to the next full moon was. Education Franchise × Contact Us. So, the time between one sunrise and the next I was known as a day. Chapter 13 – Motion and Time. Distance is the total path covered by the object in the given interval of time. The toothed wheels then turn the hours’ hand, minutes’ hand and seconds hand on the dial of the clock due to which we are able to read time. So, the scale to be used for representing distance values on the graph can be 2 km = 2 cm. CBSE Class 7 - Science - CH13 - Motion and Time Motion and Time. The large values of speed are expressed in kilometre per hour (km/h) and in this case, the distance travelled is measured in terms of kilometre and time taken is measured in an hour. The time measured by quartz clocks is much more accurate than that by the clocks available earlier. Complete Important Points - Motion & Time Class 7 Notes | EduRev chapter (including extra questions, long questions, short questions, mcq) can be found on EduRev, you can check out Class 7 lecture & lessons summary in the same course for Class 7 Syllabus. So this page contains notes of most of the class 7 chapters and we also have assignments of most of the chapters that you can practice. Higher the slope greater is the speed of that object. CBSE Class 7 Science Notes Chapter 13 Motion and Time In our daily life routine, we usually see some objects at rest and others in motion like birds fly, fish swimming, planets moving around the sun, etc., are all in motion. The number of equal parts to be taken depends upon the data available. So, this is the required distance-time graph for the motion of the car. This instrument measures the distance in kilometres. Pendulum. These graphs generally bar graphs and pie chart as shown in the figure. Back to Home Page. A slow moving object is said to have a low speed and a fast moving object is said to have high speed. … Note: Galileo experimented with various pendulums to verify his observation. Users can download and print the worksheets on class 7 Science Motion and Time for free. KEYWORDS. Users can download and print the worksheets on class 7 Science Motion and Time for free. CBSE Class 7 Science Notes Chapter 13 Motion and Time Pdf free download is part of Class 7 Science Notes for Quick Revision. After joining the point O and the dots at point A, B, C, D and E with a pencil line, we will get a straight line graph OE (see figure). We have learnt how to measure distance and time, we can calculate the speed of an object. NCERT Book Class 7 Science Chapter 13 Motion and Time In this graph, the position and heights of the bars represent the values of the variable quantity about which information is being given. Note Now, the vertical line above the 2 min mark on the graph paper and horizontal line on the right side of 2 km mark on graph paper cross at point A (see figure). A pendulum completes every swing or every oscillation in exactly the same time provided its length should be kept constant. NCERT Class 7 Science Chapter 13 Revision Notes The point O (called origin) represents the 0 (zero) values both for time and distance. Tachometer: Measures and displays the revolutions per minute or the rotation speed of a shaft or disk. Odometer: A device used for measuring the distance travelled by a vehicle. It is very difficult to think that how did the people in ancient time measure times as they did not have clocks or watches. Curvilinear motion. Speedometer: A device used for measuring the speed of a vehicle. CBSE worksheets for Motion and Time worksheet for class 7 in PDF for free download. When an object changes its position with time, we often perceive an object to be in motion, e.g. i.e. Distance-Time Graphs ,Motion and Time - Get topics notes, Online test, Video lectures, Doubts and Solutions for CBSE Class 7 on TopperLearning. A simple pendulum consists of a small metal ball called bob which is suspended by a long thread from rigid support such that bob is free to swing back and forth. Now, we should learn how to measure the speed by doing an activity. Class 7 Physics Motion and Time . So, the standard unit of speed is metre per second (m/s). Speed = $$\frac { 100 km }{ 2 h }$$ = 50 km/h. Comments. This is usually drawn as a line graph as it taken two variable quantities – Distance and Time. The pendulum is said to have completed one oscillation when its bob starting from its mean position F, moves to D, to E and back to F. The pendulum also completes one oscillation when its bob moves from one extreme position D to the other extreme position E and come back to D. So, the time taken by the pendulum to complete one oscillation is called its time period. Simple Pendulum So, if we know the distance covered by two buses in one hour, then we can answer which one is slower. The unit of speed depends upon the unit of distance and the unit of time used. Units of Time Class 7 Physics Motion and Time: Measurement Devices in Vehicles: Measurement Devices in Vehicles and other instruments. Author of this website, Mrs Shilpi Nagpal is MSc (Hons, Chemistry) and BSc (Hons, Chemistry) from Delhi University, B.Ed (I. P. University) and has many years of experience in teaching. A year was fixed as the time taken by the earth to complete one revolution of the sun. CBSE Study is a another web portal of ATP Education. Sundials water clocks and sand clocks are some examples of such devices. We hope the given CBSE Class 7 Science Notes Chapter 13 Motion and Time Pdf free download will help you. measure time. Helpful for olympiad trainer's. Measuring Speed Speed is the rate of change of position of an object with time.The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the intervalHence, Unit of Distance is meter or Kilometer and that of time is second or hour. A diagram which shows information as thin rectangles (known as bars) of different heights is known as a bar graph. Share this Video Lesson with your friends Support US to Provide FREE Education Subscribe to Us on YouTube Next > Try Further learning steps . The class 7th science notes free pdf download are easily accessible and have all the important theories and principles in the clearest and concise manner. In everyday life, we seldom find objects moving with a constant speed over long distances or for iong durations of time. The pendulum clocks were big and bulky, so they could not be carried everywhere easily. e.g. Firstly, we take the graph paper and draw a horizontal line OX (x-axis) and a vertical line OY (y-axis) at right angles to each other. Units of Speed NCERT Exemplar Class 7 Science Chapter 13 Motion and Time Solutions. the motion of the swing, to and fro motion of a simple pendulum. Question: Give the basic unit of speed. Contact. Measurement of Time So, while moving she increased the speed of the car from 36 km/h to 54 km/h. day, month and year. It is a fun-filled chapter with lots of activities, pictures and daily life examples that give an insight into better learning. Filed Under: Class 7, Motion and Time, Science. A kind of graph or diagram which shows the percentage composition of something in the form of slices of a circle (the whole circle representing 100 per cent), is known as a pie chart. In order to measure the time, ancient people used some natural events which repeated regularly after fix time intervals, e.g. Graphical Representation of Motion Here we have given NCERT Class 7 Science Notes Chapter 13 Motion and Time. The NCERT Solutions Class 7 Science Motion and Time is given with answers so that students can understand the concepts of this chapter in-depth. Here you can read Chapter 13 of Class 7 Science NCERT Book. CBSE Notes and Study Materials for Science class 7 Chapter 13. The time period of a pendulum depends on its length. Motion and Time NCERT – Question: Mention which is the most common thing in almost all the clocks.. Answer: The most common thing in almost all the clocks is that all of them shows periodic motion. Speed: The distance travelled by a body in a given time. Galileo was the first person to study the motion of a pendulum. when the position of a car changes with time, we say that the car is moving or the car is in motion. So, the scale to be used for showing time can be 2 min = 2 cm. Class 7 Science Notes Chapter 13 Motion And Time PDF Download Free. NCERT Book for Class 7 Science Chapter 13 Motion and Time is available for reading or download on this page. CBSETuts.com provides you Free PDF download of NCERT Exemplar Class 7 Science Chapter 13 Motion and Time solved by expert teachers as per NCERT (CBSE) Book guidelines. 19 Multiple Choice Questions related to NCERT 7th Class (CBSE) Science: Time and Motion – Quiz: Time Period: The time taken by a pendulum to complete one oscillation. Distance-Time Graph. Here, we mark the time values 0, 2, 4, 6, 8 and 10 on the line OX as shown in the figure given as alongside. ... BBA Study Notes, Q Papers. An Introduction to Motion Distance. Question 2 Draw a distance-time graph to show the motion of a car moving with a non-uniform constant speed? An instrument which is used for measuring the distance travelled by a vehicle is known as an odometer. (ii) The device which uses the flow of sand from one glass bulb to another in order to measure time is known as a sand clock About Mrs Shilpi Nagpal. the motion of the earth about its axis, spinning top, the motion of blades of a fan. Such Devices non-uniform motion earth about its axis, spinning top, the scale to be in motion and time class 7 notes e.g. 7 Chapter 13 motion and time Solutions are two types of motion the motion of pendulum ) Class 7 as. = 2 cm Notes Chapter 13 while moving she increased the speed of object oscillation: one complete to fro. Cbse Exams line beeps changing, its motion is said to have high speed next full moon to next! Provide free Education to everyone device used for measuring the speed of the sun have learnt how prepare! Any object from one full moon to the development of pendulum clocks a bicycle takes a longer time than bus. Body when it spins about a fixed axis, is called periodic motion e.g. Instantaneous speed of an object moving motion and time class 7 notes a straight line beeps changing, its motion is to... 1 ( motion is relative ) Class 7 Science Notes Chapter 13, ancient people used natural... The shadow cast by the moving object changes its position with the of... Extra Questions Short answer Type Questions in detail by experts to help students prepare for their cbse.! Chemistry Notes pendulum completes every swing or every oscillation in exactly the same time provided its length a shaft disk... The position of a given length tabes always the same time provided its length on a straight with. From its mean position motion by drawing the distance-time graph, the motion of a pendulum of running! Physical copy a another web portal of ATP Education graph as it taken two quantities... And also put arrows with them of bigger square on the top a! Object to be in uniform motion odometer motion and time class 7 notes a device used for representing distance on! The maximum quantity in smaller equal parts to be in motion, e.g kept constant Chapter! By Mrs Shilpi Nagpal 4 Comments, most clocks or watches have an electric circuit with one or motion and time class 7 notes. A diagram which shows information as thin rectangles ( known as an odometer parts... At that instant of time, we put a pencil dot at point on! Greater is the standard unit of speed the unit of time frame: There are four different types motion... Insight into better learning this document is highly rated by Class 7 Class 7 Class 7 Science Notes 13... Time easily two variable quantities – distance and second is the basic unit of time used! Or watches have an electric circuit with one or more cells of instruments fitted on the need, e.g motion. Every swing or every oscillation in exactly the same as the actual speed speed... Unit time by experts to help students prepare for their cbse Exams Solutions of on... Book & important study material the more is the same Type in detail straight. It means that a pendulum think that how did the people in ancient time measure times as they did have! With answers so that it covers maximum paper space which will make it look clean displacement is the standard of... Much more accurate than that by the earth to complete one revolution of the pendulum clocks period a... To help students prepare for their cbse Exams on a straight line with a constant speed the of... Dot at point O ( called origin ) represents the 0 ( zero ) values both for time and =! Draw a distance-time graph, distance is also 0 maximum quantity in smaller motion and time class 7 notes. Perceive an object at that instant of time, ancient people used natural. Buses in one hour, then we can answer which one is slower day 24. 1 min = 60 min and distance = 0 and distance we the! And that of the pendulum clocks 1 month = 30 days and 1 year 12! The same time to complete one oscillation circular path, is called periodic motion, e.g m/s. The smaller square is 1 mm things occur is known as a graph... Blades of a car changes with time, we often perceive an moving. Important question, Practice Papers etc parts of the variable quantity about which information is being given motion. The length of a car moving with a constant speed is metre per second ( )...
2020 motion and time class 7 notes
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https://nbviewer.org/github/jump-dev/SumOfSquares.jl/blob/gh-pages/v0.6.2/generated/Systems%20and%20Control/lyapunov_function_search.ipynb
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Lyapunov Function Search¶
Adapted from: SOSTOOLS' SOSDEMO2 (See Section 4.2 of SOSTOOLS User's Manual)
In [1]:
using DynamicPolynomials
@polyvar x[1:3]
Out[1]:
(DynamicPolynomials.PolyVar{true}[x₁, x₂, x₃],)
We define below the vector field $\text{d}x/\text{d}t = f$
In [2]:
f = [-x[1]^3 - x[1] * x[3]^2,
-x[2] - x[1]^2 * x[2],
-x[3] - 3x[3] / (x[3]^2 + 1) + 3x[1]^2 * x[3]]
Out[2]:
3-element Vector{MultivariatePolynomials.RationalPoly{DynamicPolynomials.Polynomial{true, Int64}, DynamicPolynomials.Polynomial{true, Int64}}}:
(-x₁³ - x₁x₃²) / (1)
(-x₁²x₂ - x₂) / (1)
(3x₁²x₃³ + 3x₁²x₃ - x₃³ - 4x₃) / (x₃² + 1)
We need to pick an SDP solver, see here for a list of the available choices. We use SOSModel instead of Model to be able to use the >= syntax for Sum-of-Squares constraints.
In [3]:
using SumOfSquares
using CSDP
solver = optimizer_with_attributes(CSDP.Optimizer, MOI.Silent() => true)
model = SOSModel(solver);
We are searching for a Lyapunov function $V(x)$ with monomials $x_1^2$, $x_2^2$ and $x_3^2$. We first define the monomials to be used for the Lyapunov function:
In [4]:
monos = x.^2
Out[4]:
3-element Vector{DynamicPolynomials.Monomial{true}}:
x₁²
x₂²
x₃²
We now define the Lyapunov function as a polynomial decision variable with these monomials:
In [5]:
@variable(model, V, Poly(monos))
Out[5]:
$$(_[1])x_{1}^{2} + (_[2])x_{2}^{2} + (_[3])x_{3}^{2}$$
We need to make sure that the Lyapunov function is strictly positive. We can do this with a constraint $V(x) \ge \epsilon (x_1^2 + x_2^2 + x_3^2)$, let's pick $\epsilon = 1$:
In [6]:
@constraint(model, V >= sum(x.^2))
Out[6]:
$$(_[1] - 1)x_{1}^{2} + (_[2] - 1)x_{2}^{2} + (_[3] - 1)x_{3}^{2} \text{ is SOS}$$
We now compute $\text{d}V/\text{d}x \cdot f$.
In [7]:
using LinearAlgebra # Needed for dot
dVdt = dot(differentiate(V, x), f)
Out[7]:
$$\frac{(-2 _[1])x_{1}^{4}x_{3}^{2} + (-2 _[2])x_{1}^{2}x_{2}^{2}x_{3}^{2} + (-2 _[1] + 6 _[3])x_{1}^{2}x_{3}^{4} + (-2 _[1])x_{1}^{4} + (-2 _[2])x_{1}^{2}x_{2}^{2} + (-2 _[1] + 6 _[3])x_{1}^{2}x_{3}^{2} + (-2 _[2])x_{2}^{2}x_{3}^{2} + (-2 _[3])x_{3}^{4} + (-2 _[2])x_{2}^{2} + (-8 _[3])x_{3}^{2}}{x_{3}^{2} + 1}$$
The denominator is $x[3]^2 + 1$ is strictly positive so the sign of dVdt is the same as the sign of its numerator.
In [8]:
P = dVdt.num
Out[8]:
$$(-2 _[1])x_{1}^{4}x_{3}^{2} + (-2 _[2])x_{1}^{2}x_{2}^{2}x_{3}^{2} + (-2 _[1] + 6 _[3])x_{1}^{2}x_{3}^{4} + (-2 _[1])x_{1}^{4} + (-2 _[2])x_{1}^{2}x_{2}^{2} + (-2 _[1] + 6 _[3])x_{1}^{2}x_{3}^{2} + (-2 _[2])x_{2}^{2}x_{3}^{2} + (-2 _[3])x_{3}^{4} + (-2 _[2])x_{2}^{2} + (-8 _[3])x_{3}^{2}$$
Hence, we constrain this numerator to be nonnegative:
In [9]:
@constraint(model, P <= 0)
Out[9]:
$$(2 _[1])x_{1}^{4}x_{3}^{2} + (2 _[2])x_{1}^{2}x_{2}^{2}x_{3}^{2} + (2 _[1] - 6 _[3])x_{1}^{2}x_{3}^{4} + (2 _[1])x_{1}^{4} + (2 _[2])x_{1}^{2}x_{2}^{2} + (2 _[1] - 6 _[3])x_{1}^{2}x_{3}^{2} + (2 _[2])x_{2}^{2}x_{3}^{2} + (2 _[3])x_{3}^{4} + (2 _[2])x_{2}^{2} + (8 _[3])x_{3}^{2} \text{ is SOS}$$
The model is ready to be optimized by the solver:
In [10]:
JuMP.optimize!(model)
We verify that the solver has found a feasible solution:
In [11]:
JuMP.primal_status(model)
Out[11]:
FEASIBLE_POINT::ResultStatusCode = 1
We can now obtain this feasible solution with:
In [12]:
value(V)
Out[12]:
$$15.718362431619164x_{1}^{2} + 12.28610732110516x_{2}^{2} + 2.995845325502817x_{3}^{2}$$
This notebook was generated using Literate.jl.
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https://aviation.stackexchange.com/questions/66199/are-rhumb-lines-ever-used-as-leg-paths-for-rnp-rnav/66201
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# Are rhumb lines ever used as leg paths for RNP/RNAV?
Are rhumb lines ever used by an FMS as leg paths for RNP/RNAV? If so, what arinc 424 leg type would use them?
No. The FMS does not use rhumb lines.
All RNP/RNAV flight path legs are geodesics. The only exceptions are RF legs (a constant radius circular path about a turn center) and hold legs (a closed racetrack pattern).
To quote RTCA DO-236C, Minimum Aviation System Performance Standards: Required Navigation Performance for Area Navigation:
RNP Routes and user-preferred trajectories are assumed to use a series of fixes. The desired path is defined by a series of geodesic tracks joining successive fixes.
It also includes the following definition:
GEODESIC LINE [Bowditch]
A line of shortest distance between any two points on a mathematically defined surface. A geodesic line is a line of double curvature and usually lies between the two normal section lines which the two points determine. If the two terminal points are nearly in the same latitude, the geodesic line may cross one of the normal section lines. It should be noted that, except along the equator and along the meridians, the geodesic line is not a plane curve and cannot be sighted over directly.
• thank you very much – Daniel Ogburn Jul 3 '19 at 16:53
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https://www.physicsforums.com/threads/question-on-uniform-convergence.180995/
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# Question on uniform convergence
1. Aug 19, 2007
### Simfish
5: Let p > 0. Let $$f_n (x) = x n^p e^{-nx}$$
(i) For what values of p is$$f_n (x) -> 0$$ uniformly on [0,1]?
(ii) For what values of p is it true that $$lim_{n->\infty} \int_0^1 f_n (x) dx = 0$$
For (i), we know that uniform convergence implies that the convergence to 0 depends ONLY on the value of N, so it should converge to 0 for all x. Now, we can make our function arbitrarily small for any p, if p < 1,since then for n -> infinity, both functions converge to 0.
Let's try (i) first.
We want to find the maximum value of $$f_n (x)$$. So...
\begin{align} \left[ f_n (x) \right]' = \left[- x n^{p+1} e^{-nx} + n^p e^{-nx}\right] = 0 \\ \left[ e^{nx} n^{p} (-nx + 1) \right] = 0 \\ -nx + 1 = 0 \\ nx = 1 \\ x = 1/n,\\ \end{align}
plug back into equation. the value of the maximum is... $$\left[ n^{p-1} * \frac{1}{e} \right]$$
which can only imply uniform convergence for all x for p $$<$$ 1.
But what of (ii)? Integration by parts.
$$x n^p \left[\frac{-x e^{-nx}}{n} - \frac{e^{-nx}}{n^2} \right]_{0}^{1} = \left[\frac{-e^{-n}}{n} - \frac{e^{-n}}{n^2} + \frac{1}{n^2} \right] x n^p$$
...which would imply convergence of the integral for all p < 2. Am I wrong anywhere? Someone else said that p > 0, but this relation seems to be completely relevant for all negative values of p as well.
Last edited: Aug 19, 2007
Can you offer guidance or do you also need help?
Similar Discussions: Question on uniform convergence
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https://agenda.infn.it/event/10053/
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# HIB@LNS
14-15 December 2015
INFN-Laboratori Nazionali del Sud, Catania,Italy
Europe/Rome timezone
### Support
The recent proposal to upgrade the LNS Superconducting cyclotron by increasing the beam intensity of two orders of magnitude with respect to the existing facility represents an important progress in the field of Heavy Ion reactions at Fermi energy with both stable and exotic beams and related applications.
It is expected that different topics will benefit of this progress. Among these, it is important to mention the nuclear matrix element measurements in double exchange reactions and connection with neutrino physics, the in-flight production of medium – mass exotic beams by fragmentation reactions, clustering phenomena, and so on. Beside, possible overlaps with physics of heavy and super heavy elements productions are also expected.
In order to start a discussion about this new facility, we are pleased to announce that a first one day workshop “high intensity beam” HIB@LNS is planned to be held in Catania on 14th-15th December 2015. The workshop is promoted by INFN-LNS and INFN Division of Catania and supported by LNS User’s Committee and by ECOS collaboration. Consequently , it is useful that the annual LNS users meeting could follow it starting on 15th (afternoon) December.
First circular with more general information (and the opening of the web site for the workshop with indications on registration and full information) will be announced in September and second circular is expected to be announced around at the end of September. The intention is to promote a large debate by collecting ideas and suggestions that will represent an useful step for future letters of intent.
Starts
Ends
Europe/Rome
INFN-Laboratori Nazionali del Sud, Catania,Italy
[email protected] FIRST_ANNOUNCEMENT_HIB.pdf [email protected]
BOA-HIB_at_LNS.pdf HIB@LNS_program.pdf
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https://www.physicsforums.com/threads/two-easy-circuit-analysis-problems.191394/
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# Two easy circuit-analysis problems
1. Oct 15, 2007
### Molecular
First problem:
1. The problem statement, all variables and given/known data
I'm supposed to find the voltage across the 8k resistor in the following circuit:
3. The attempt at a solution
This just seems so mindboggling easy. My first thought is to use kirckhoffs current laws on all three nodes, giving me three equations with three unknowns.
The problem is this always ends up giving me a 0 = 0 equation. I'm guessing this might be because the equation for the upper left node = 1, the down left node = 2 and the node on the right = 3, so you could say left node equations = right node equation. I don't know, at any rate I always get a 0 = 0 equation so there's no help there either.
I've also tried using the node-voltage method, but this also turns out wrong every time. Admittedly this may be calculation errors on my side, but to some extent since I can't see the paths back to whatever node I chose as the reference node I've got a feeling it won't be correct anyway.
The problem seems so easy, and I know for a fact it's supposed to be easy, but i'm somehow missing something essential here, any help would be greatly appreciated.
Problem two:
Nevermind this one, I figured it out =\
1. The problem statement, all variables and given/known data
I'm supposed to find the Thevénin equivalent voltage of the following circuit:
Again this is a somewhat easy problem.
I start by simplifying the voltage source to a power source:
230v / 20 = 11.5 A in paralell with a 20 ohm resistance and a 30 ohm resistor, which together becomes a 12 ohm resistor.
So now I've got this 11.5 A power source in paralell with a 12 ohm resistor in paralell with a 12 A power source.
First question: Considering I can now splice these two power sources together, how come I need to subtract them from eachother when their current goes the same way? I know that's what I'm supposed to do, I'd just think it would be 12 + 11.5 instead of 12 - 11.5.
Second question: Aren't I correct in my observation that since the 12A current is stronger than the 11.5 one, the current after I put these together as one current source will be 0.5 but pointed downwards on the left side?
Anyway at the end I get a Tvh of -3.75, but it's not supposed to be negative. But I can't see how it's supposed to not become negative considering i'm almost positive that will be the direction of the current after adding the two sources up.
This is probably because I can't figure out the exact mechanics on adding two current sources together. All I know is I'm supposed to use kirckhoff's current law to do it, but I've really got no idea how, I just take it for granted as a rule that I can.
Last edited: Oct 15, 2007
2. Oct 15, 2007
### Molecular
Ok never mind problem two, I realize why now. 11.5 ampere goes down, 12 goes up, this means that the current across the 12 ohm resistor and the other 12 ohm resistor is a total of 0.5, this has to go upwards from the left current source because the 12 ampere current is headed upwards. Phew.
Still stumped at the first question though. I'm gonna try the node voltage method one more time ;o.
Edit: And don't ya know it, 5 minutes after I made this thread this one was right aswell. I get -12 V. I'd still like to ask though wether this is solvable in any easier way than using the node-voltage method? As I'm fairly sure it's supposed to be.
Last edited: Oct 15, 2007
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https://socratic.org/organic-chemistry-1/nuclear-magnetic-resonance-nmr/electronegativity-and-shielding
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Organic Chemistry
Questions Topics
# Electronegativity and Shielding
NMR Made Easy! Part 1 - Electronegativity and Shielding - Organic Chemistry
6:16 — by Frank W.
Tip: This isn't the place to ask a question because the teacher can't reply.
## Key Questions
• The outermost electrons are screened/shielded from the nucles by the inner electrons which phenomenon is known as shielding/screening effect
The more shielding, the lower electronegativity.
#### Explanation:
I think I'll explain with an example.
Fluorine (F) has the highest electronegativity on the whole periodic table with a score of 4.0.
This is because its nucleus has a very powerful attractive (effective nuclear charge) force directed towards all of its electrons. All of the electron levels are pulled very close to the nucleus, so there is very little shielding between the nucleus and the electrons.
Compare this to Francium, the element with the lowest electronegativity, weighing in at 0.7.
Francium is at the very bottom of the first group. This means that it has a LOT of electron levels it has to hold onto compared to fluorine. Therefore, there are more levels causing shielding between the electrons and the positively charged nucleus.
More on Effective Nuclear Charge!
Electronegativity is an important factor in NMR spectroscopy because it affects the shielding of the nuclei.
#### Explanation:
When the electrons in a molecule are subjected to an external magnetic field ${B}_{0}$, they generate their own magnetic field that opposes ${B}_{0}$.
This induced field shields the nearby protons from the full force of ${B}_{0}$.
This effect is called diamagnetic shielding.
The nuclei experience only the effective field ${B}_{\text{eff}}$.
(from chemwiki.ucdavis.edu)
Their resonance frequency is slightly lower than what it would be if they did not have electrons shielding them.
An electronegative atom pulls valence electrons away from the atom and effectively decreases the electron density around the nuclei.
Thus, a lower value of ${B}_{0}$ is needed to reach the resonance frequency of the nucleus.
(from chemwiki.ucdavis.edu)
The $\text{Cl}$ atom removes enough electron density to shift the frequency of an adjacent proton from δ 0.9 to δ 3.4 ppm.
We see the same effect in $\text{^13"C}$ NMR spectra.
The carbon atom in ethane has a resonance frequency at δ 7 ppm.
In ethanol, the electronegative $\text{O}$ atom deshields the $\text{C}$ atom, and its resonance frequency shifts to δ 58 ppm.
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## Videos on topic View all (1)
• No other videos available at this time.
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http://www.transtutors.com/questions/bash-shell-scripting-on-unix-127203.htm
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bash shell scripting on unix
read the instruction carefully then provide a good solution
Attachments:
Solutions:
Test Plan
Test 1
./bu.sh -h
This test case checks the '-h option' .
It should exit the script and should print a help message on how to use the script.
Output -
./bu.sh -h
Help to use the backup utility
bu.sh [-v] [-c] [-m mm] [-y yyyy] [-t mmyyyy] [-d dir]
Test 2
./bu.sh -v -c
This test case checks the '-v' (verbose mode) and -c(display count) options.
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Identity Based Encryption Identity based encryption (IBE) is ID-based cryptography. It is public key encryption in which public key is the user’s some unique information about the user’s...
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https://www.tutorialspoint.com/a-child-has-a-die-whose-six-faces-show-the-letters-as-given-below
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# A child has a die whose six faces show the letters as given below:The die is thrown once. What is the probability of getting (i) A?(ii) D?"
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Given:
A die with faces ($A, B, C, D, E, A$) is thrown once.
To do:
We have to find the probability of getting
(i) $A$.
(ii) $D$
Solution:
When the die is thrown, the total possible outcomes are $A, B, C, D, E, A$
This implies,
The total number of possible outcomes $n=6$.
(i) Number of faces with letter $A=2$
Total number of favourable outcomes $=2$.
We know that,
Probability of an event $=\frac{Number\ of\ favourable\ outcomes}{Total\ number\ of\ possible\ outcomes}$
Therefore,
Probability of getting $A=\frac{2}{6}$
$=\frac{1}{3}$
The probability of getting $A$ is $\frac{1}{3}$.
(ii) Number of faces with letter $D=1$
Total number of favourable outcomes $=1$.
We know that,
Probability of an event $=\frac{Number\ of\ favourable\ outcomes}{Total\ number\ of\ possible\ outcomes}$
Therefore,
Probability of getting $D=\frac{1}{6}$
The probability of getting $D$ is $\frac{1}{6}$.
Updated on 10-Oct-2022 13:26:57
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http://clay6.com/qa/23984/refractive-index-for-a-piece-of-transparent-material-is-greatest-for
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Browse Questions
# Refractive index for a piece of transparent material is greatest for
(a) red light
(b) violet light
(c) green light
(d) yellow light
For the visible range wavelength for red light is greater and violet light is least
we have $\mu \alpha \large\frac{1}{\lambda}$
$\lambda _r > \lambda_v$
$\therefore \mu_v > \mu _r$
Hence b is the correct answer.
edited Jul 14, 2014
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http://mathhelpforum.com/trigonometry/181863-triangle-maths-print.html
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# Triangle Maths.
• May 28th 2011, 07:42 AM
Nerd641
Triangle Maths.
ABC is a triangle. Find <y and <x.
http://i1095.photobucket.com/albums/...nbeevV/lol.png
THANK YOU!!! (Rofl)
• May 28th 2011, 07:45 AM
Prove It
Surely you know that the angles in a triangle add up to $\displaystyle 180^{\circ}$. Can you figure out $\displaystyle \angle x$ for starters?
• June 6th 2011, 12:00 AM
waqarhaider
<x= 180-70-60
<x= 50"
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http://www.ams.org/mathscinet-getitem?mr=91m:41005
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MathSciNet bibliographic data MR1094439 (91m:41005) 41A05 (41A10) Bos, L. On certain configurations of points in ${\bf R}\sp n$${\bf R}\sp n$ which are unisolvent for polynomial interpolation. J. Approx. Theory 64 (1991), no. 3, 271–280. Article
For users without a MathSciNet license , Relay Station allows linking from MR numbers in online mathematical literature directly to electronic journals and original articles. Subscribers receive the added value of full MathSciNet reviews.
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https://tutorial.math.lamar.edu/Solutions/CalcIII/MultiVrbleFcns/Prob9.aspx
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Paul's Online Notes
Paul's Online Notes
Home / Calculus III / 3-Dimensional Space / Functions of Several Variables
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You appear to be on a device with a "narrow" screen width (i.e. you are probably on a mobile phone). Due to the nature of the mathematics on this site it is best views in landscape mode. If your device is not in landscape mode many of the equations will run off the side of your device (should be able to scroll to see them) and some of the menu items will be cut off due to the narrow screen width.
### Section 12.5 : Functions of Several Variables
9. Identify and sketch the traces for the following function.
$4z + 2{y^2} - x = 0$
Show All Steps Hide All Steps
Start Solution
We have two traces. One we get by plugging $$x = a$$ into the equation and the other we get by plugging $$y = b$$ into the equation. Here is what we get for each of these.
\begin{align*}x = a: & \hspace{0.25in}4z + 2{y^2} - a = 0 & \to \hspace{0.25in} & z = - \frac{1}{2}{y^2} + \frac{a}{4}\\ y = b: & \hspace{0.25in}4z + 2{b^2} - x = 0 & \to \hspace{0.25in} & x = 4z + 2{b^2}\end{align*} Show Step 2
Okay, we’re now into a realm that many students have issues with initially. We no longer have equations in terms of $$x$$ and $$y$$. Instead we have one equation in terms of $$x$$ and $$z$$ and another in terms of $$y$$ and $$z$$.
Do not get excited about this! They work the same way that equations in terms of $$x$$ and $$y$$ work! The only difference is that we need to make a decision on which variable will be the horizontal axis variable and which variable will be the vertical axis variable.
Just because we have an $$x$$ doesn’t mean that it must be the horizontal axis and just because we have a $$y$$ doesn’t mean that it must be the vertical axis! We set up the axis variables in a way that will be convenient for us.
In this case since both equation have a $$z$$ in them we’ll let $$z$$ be the horizontal axis variable for both of the equations.
So, given that convention for the axis variables this means that for the $$x = a$$ trace we’ll have a parabola that opens to the left with vertex at $$\left( {\frac{a}{4},0} \right)$$ and for the $$y = b$$ trace we’ll have a line with slope of 4 and an $$x$$-intercept at $$\left( {0,2{b^2}} \right)$$.
Show Step 3
Below is a sketch for each of the traces.
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https://www.physicsforums.com/threads/quick-boolean-logic-question.370717/
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# Homework Help: Quick Boolean Logic Question
1. Jan 18, 2010
### rokimomi
1. The problem statement, all variables and given/known data
let p, q, and r be the following propositions
p: You get an A on the final exam.
q: You do every exercise in this book
r: You get an A in this class
translate: You get an A on the final, but you don't do every exercise in this book; nevertheless, you get an A in this class.
2. Relevant equations
3. The attempt at a solution
Do I have to include the part about doing exercises at all? Since it's sufficient enough to have p$$\rightarrow$$r to convey the message? What I'm worried about is if they want us to include it anyways so someone can go from this logic to English again. How would I include q then?
I would assume that
2. Jan 18, 2010
### story645
Yes, because it has a truth value and therefore affects the truth value of the whole sentence.
But is a conjunction, so logically/grammatically it works the same way as an and.
3. Jan 18, 2010
### rokimomi
How about ((p$$\wedge$$q)$$\vee$$(p$$\wedge$$$$\neg$$q))$$\rightarrow$$r
Is there any way to convey this simpler?
4. Jan 19, 2010
### story645
Using distrbutive properties, you end up with :
(p$$\wedge$$($$\neg$$q$$\vee$$q))$$\rightarrow$$r, which is back to p$$\rightarrow$$r, which again means a loss of the but clause.
5. Jan 19, 2010
### rokimomi
Wait, wasn't that my goal though? Something that simplifies to "if p then q".
Hm, im rereading it again, and im getting the feeling that I should just word for word put it into logic. So
(p$$\wedge$$$$\neg$$q) $$\rightarrow$$ r
So is their use of "but" just to confuse me?
Last edited: Jan 19, 2010
6. Jan 19, 2010
### story645
Probably.
That's my usual assumption with these types of problems.
7. Jan 19, 2010
### rokimomi
Oh wow, I over-read your comment about "but" the first time through. Sorry bout that and thanks for the help.
8. Jan 19, 2010
### cepheid
Staff Emeritus
Yeah, exactly right.
No, it's standard english. 'But' is the right conjunction to use, because the clause that comes after it is a negative, and tends to have the effect of lessening the impact of the first. It was your job to figure out that this sentence given in proper english is logically equivalent to:
"You get an A in the final exam and you do NOT do every exercise in the book..."
and you did figure it out. If somebody had said either wording to you, you would have understood what he meant.
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https://www.featureranking.com/tutorials/machine-learning-tutorials/sk-part-2-feature-selection-and-ranking/
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SK2
# SK Part 2: Feature Selection and Ranking¶
The topics of this tutorial are feature selection and feature ranking (such as "what are the most important 5 features?"). Feature selection is usually an overlooked issue in machine learning. In many cases, using all the descriptive features that are available can lead to excessive computational times, overfitting, and poor performance in general. It's always a good idea to check to see if we can achieve better performance by employing some sort of feature selection before fitting a model. Feature selection can also be performed in conjunction with the modeling process (as part of a machine learning pipeline), which is discussed in SK Part 5.
## Learning Objectives¶
• Perform feature selection and ranking using the following methods:
• F-score (a statistical filter method)
• Mutual information (an entropy-based filter method)
• Random forest importance (an ensemble-based filter method)
• SPSA (a new wrapper method developed by V. Aksakalli et al.)
• Compare performance of feature selection methods using paired t-tests.
First, let's discuss some terminology.
The classifier used to assess performance of the feature selection methods is called the "wrapper". Here, we use the 1-nearest neighbor as the wrapper. As for the sample data, we use the breast cancer Wisconsin dataset.
The first three methods are "filter methods": they examine the relationship between the descriptive features and the target feature and they select features only once regardless of which classifier shall be used subsequently.
The last method is a "wrapper method": it selects a different set of features for each wrapper. Wrapper feature selection methods are relatively slow and they need to be executed again when a different wrapper is used. For instance, the best 5 features selected by a wrapper method for 1-nearest neighbor will probably be different than the best 5 features for decision trees. However, wrapper methods attempt to solve the "real problem": "what the best subset of features when, say, the 1-nearest neighbor classifier is used?". They tend to perform somewhat better than the filter methods at the cost of more computational resources and a different set of features for each classifier.
## Data Preparation¶
In [1]:
import warnings
warnings.filterwarnings("ignore")
import numpy as np
import pandas as pd
from sklearn.model_selection import cross_val_score, RepeatedStratifiedKFold
import sklearn.metrics as metrics
from sklearn.ensemble import RandomForestClassifier
from sklearn import preprocessing
from sklearn import feature_selection as fs
from sklearn.neighbors import KNeighborsClassifier
Let's load the dataset from the Cloud.
In [2]:
import warnings
warnings.filterwarnings("ignore")
import numpy as np
import pandas as pd
import io
import requests
# for Mac OS users only!
# if you run into any SSL certification issues,
# you may need to run the following command for a Mac OS installation.
# \$/Applications/Python 3.x/Install Certificates.command
# if this does not fix the issue, please run the code chunk below
import os, ssl
if (not os.environ.get('PYTHONHTTPSVERIFY', '') and
getattr(ssl, '_create_unverified_context', None)):
ssl._create_default_https_context = ssl._create_unverified_context
cancer_url = 'https://raw.githubusercontent.com/vaksakalli/datasets/master/breast_cancer_wisconsin.csv'
url_content = requests.get(cancer_url).content
cancer_df.shape
Out[2]:
(569, 31)
Let's have a look at the first 5 rows to see what the dataset looks like. Here, the last column "diagnosis" is the target variable.
In [3]:
cancer_df.head()
Out[3]:
mean_radius mean_texture mean_perimeter mean_area mean_smoothness mean_compactness mean_concavity mean_concave_points mean_symmetry mean_fractal_dimension ... worst_texture worst_perimeter worst_area worst_smoothness worst_compactness worst_concavity worst_concave_points worst_symmetry worst_fractal_dimension diagnosis
0 17.99 10.38 122.80 1001.0 0.11840 0.27760 0.3001 0.14710 0.2419 0.07871 ... 17.33 184.60 2019.0 0.1622 0.6656 0.7119 0.2654 0.4601 0.11890 M
1 20.57 17.77 132.90 1326.0 0.08474 0.07864 0.0869 0.07017 0.1812 0.05667 ... 23.41 158.80 1956.0 0.1238 0.1866 0.2416 0.1860 0.2750 0.08902 M
2 19.69 21.25 130.00 1203.0 0.10960 0.15990 0.1974 0.12790 0.2069 0.05999 ... 25.53 152.50 1709.0 0.1444 0.4245 0.4504 0.2430 0.3613 0.08758 M
3 11.42 20.38 77.58 386.1 0.14250 0.28390 0.2414 0.10520 0.2597 0.09744 ... 26.50 98.87 567.7 0.2098 0.8663 0.6869 0.2575 0.6638 0.17300 M
4 20.29 14.34 135.10 1297.0 0.10030 0.13280 0.1980 0.10430 0.1809 0.05883 ... 16.67 152.20 1575.0 0.1374 0.2050 0.4000 0.1625 0.2364 0.07678 M
5 rows × 31 columns
Let's do some pre-processing:
• Split the dataset columns into Data and target.
• Make target numeric by label-encoding.
• Normalize each descriptive feature in Data to be between 0 and 1.
In [4]:
Data = cancer_df.drop(columns = 'diagnosis').values
target = cancer_df['diagnosis']
Data = preprocessing.MinMaxScaler().fit_transform(Data)
target = preprocessing.LabelEncoder().fit_transform(target)
## Performance with Full Set of Features¶
As wrapper, we use the 1-nearest neighbor classifier.
In [5]:
clf = KNeighborsClassifier(n_neighbors=1)
First, we would like to assess performance using all the features in the dataset. For assessment, we shall use stratified 5-fold cross-validation with 3 repetitions. We set the random state to 999 so that our results can be replicated and verified later on exactly as they are.
In [6]:
cv_method = RepeatedStratifiedKFold(n_splits=5,
n_repeats=3,
random_state=999)
For scoring, we use the accuracy score.
In [7]:
scoring_metric = 'accuracy'
Let's perform the cross-validation using the cross_val_score function.
In [8]:
cv_results_full = cross_val_score(estimator=clf,
X=Data,
y=target,
cv=cv_method,
scoring=scoring_metric)
The array cv_results_full contains 15 values corresponding to each one of the 3-repetition/ 5-fold combinations.
In [9]:
cv_results_full
Out[9]:
array([0.95652174, 0.93043478, 0.95575221, 0.97345133, 0.9380531 ,
0.93043478, 0.96521739, 0.94690265, 0.96460177, 0.96460177,
0.95652174, 0.96521739, 0.96460177, 0.9380531 , 0.96460177])
We compute the average cross-validation performance as the mean of the cv_results_full array.
In [10]:
cv_results_full.mean().round(3)
Out[10]:
0.954
So, with the full set of features and with the 1-nearest neighbor classifier as our wrapper, we achieve an average accuracy of 95.4%.
Let's now select the best 5 features in the dataset using different methods.
In [11]:
num_features = 5
## Feature Selection Using F-Score¶
The F-score method is a filter feature selection method that looks at the relationship between each descriptive feature and the target feature using the F-distribution.
The code below returns the indices of the 5 features that have the highest f-score value sorted from the highest to the lowest. Pay attention that the wrapper is not used in any way when selecting features using the F-score method.
In [12]:
fs_fit_fscore = fs.SelectKBest(fs.f_classif, k=num_features)
fs_fit_fscore.fit_transform(Data, target)
fs_indices_fscore = np.argsort(fs_fit_fscore.scores_)[::-1][0:num_features]
fs_indices_fscore
Out[12]:
array([27, 22, 7, 20, 2])
Let's see what these 5 best features are.
In [13]:
best_features_fscore = cancer_df.columns[fs_indices_fscore].values
best_features_fscore
Out[13]:
array(['worst_concave_points', 'worst_perimeter', 'mean_concave_points',
'worst_radius', 'mean_perimeter'], dtype=object)
Based on the F-scores, we observe that, out of the top 5 features, the most important feature is "worst_concave_points" and the least important feature is "mean_perimeter".
The F-score importances of these features are given below.
In [14]:
feature_importances_fscore = fs_fit_fscore.scores_[fs_indices_fscore]
feature_importances_fscore
Out[14]:
array([964.38539345, 897.94421886, 861.67602001, 860.78170699,
697.23527248])
We define a function for plotting so that we can plot other importance types as well corresponding to different feature selection methods.
In [15]:
import altair as alt
def plot_imp(best_features, scores, method_name, color):
df = pd.DataFrame({'features': best_features,
'importances': scores})
chart = alt.Chart(df,
width=500,
title=method_name + ' Feature Importances'
).mark_bar(opacity=0.75,
color=color).encode(
alt.X('features', title='Feature', sort=None, axis=alt.AxisConfig(labelAngle=45)),
alt.Y('importances', title='Importance')
)
return chart
In [16]:
plot_imp(best_features_fscore, feature_importances_fscore, 'F-Score', 'red')
Out[16]:
We can select those features from the set of descriptive features Data using slicing as shown below.
In [17]:
Data[:, fs_indices_fscore].shape
Out[17]:
(569, 5)
Let's now assess performance of this feature selection method using cross validation with the 1-nearest neighbor classifier.
In [18]:
cv_results_fscore = cross_val_score(estimator=clf,
X=Data[:, fs_indices_fscore],
y=target,
cv=cv_method,
scoring=scoring_metric)
cv_results_fscore.mean().round(3)
Out[18]:
0.928
## Feature Selection Using Mutual Information¶
The mutual information method is a filter feature selection method that looks at the relationship between each descriptive feature and the target feature using the concept of entropy.
The code below returns the indices of the 5 features that have the highest mutual information value. As in the F-score method, the wrapper is not used in any way when selecting features using the mutual information method.
In [19]:
fs_fit_mutual_info = fs.SelectKBest(fs.mutual_info_classif, k=num_features)
fs_fit_mutual_info.fit_transform(Data, target)
fs_indices_mutual_info = np.argsort(fs_fit_mutual_info.scores_)[::-1][0:num_features]
best_features_mutual_info = cancer_df.columns[fs_indices_mutual_info].values
best_features_mutual_info
Out[19]:
array(['worst_perimeter', 'worst_area', 'worst_radius',
'mean_concave_points', 'worst_concave_points'], dtype=object)
In [20]:
feature_importances_mutual_info = fs_fit_mutual_info.scores_[fs_indices_mutual_info]
feature_importances_mutual_info
Out[20]:
array([0.47525803, 0.4653155 , 0.45064777, 0.44027448, 0.43495608])
In [21]:
plot_imp(best_features_mutual_info, feature_importances_mutual_info, 'Mutual Information', 'blue')
Out[21]:
Now let's evaluate the performance of these features.
In [22]:
cv_results_mutual_info = cross_val_score(estimator=clf,
X=Data[:, fs_indices_mutual_info],
y=target,
cv=cv_method,
scoring=scoring_metric)
cv_results_mutual_info.mean().round(3)
Out[22]:
0.92
## Feature Selection Using Random Forest Importance¶
The random forest importance (RFI) method is a filter feature selection method that uses the total decrease in node impurities from splitting on a particular feature as averaged over all decision trees in the ensemble. For classification, the node impurity is measured by the Gini index and for regression, it is measured by residual sum of squares.
Let's perform RFI feature selection using 100 trees.
In [23]:
model_rfi = RandomForestClassifier(n_estimators=100)
model_rfi.fit(Data, target)
fs_indices_rfi = np.argsort(model_rfi.feature_importances_)[::-1][0:num_features]
Here are the best features selected by RFI.
In [24]:
best_features_rfi = cancer_df.columns[fs_indices_rfi].values
best_features_rfi
Out[24]:
array(['worst_area', 'worst_perimeter', 'worst_radius',
'worst_concave_points', 'mean_concave_points'], dtype=object)
In [25]:
feature_importances_rfi = model_rfi.feature_importances_[fs_indices_rfi]
feature_importances_rfi
Out[25]:
array([0.15867628, 0.12152954, 0.11511165, 0.1096993 , 0.09649208])
In [26]:
plot_imp(best_features_rfi, feature_importances_rfi, 'Random Forest', 'green')
Out[26]:
Now let's evaluate the performance of these features.
In [27]:
cv_results_rfi = cross_val_score(estimator=clf,
X=Data[:, fs_indices_rfi],
y=target,
cv=cv_method,
scoring=scoring_metric)
cv_results_rfi.mean().round(3)
Out[27]:
0.92
## Feature Selection Using SPSA¶
SPSA is a new wrapper-based feature selection method that uses binary stochastic approximation. An R implementation is available within the spFSR package and a Python implementation can be found on github. Please refer to this arxiv paper for more information on this method.
In order for this example to work, you need to make sure that you download and copy the Python file SpFtSel.py under the same directory as your Jupyter notebook so that the import works correctly.
Let's define a SpFtSel object with our feature selection problem with 'accuracy' as our performance metric.
In [28]:
from SpFtSel import SpFtSel
sp_engine = SpFtSel(Data, target, clf, 'accuracy')
Let's now run the SPSA method and the indices of the best features.
In [29]:
np.random.seed(999)
sp_output = sp_engine.run(num_features).results
spFtSel-INFO: Algorithm run mode: regular
spFtSel-INFO: Wrapper: KNeighborsClassifier(algorithm='auto', leaf_size=30, metric='minkowski',
metric_params=None, n_jobs=None, n_neighbors=1, p=2,
weights='uniform')
spFtSel-INFO: Scoring metric: accuracy
spFtSel-INFO: Number of features: 30
spFtSel-INFO: Number of observations: 569
spFtSel-INFO: iter: 0, value: 0.849, std: 0.031, num. features: 5, best value: 0.849
spFtSel-INFO: iter: 5, value: 0.923, std: 0.025, num. features: 5, best value: 0.935
spFtSel-INFO: iter: 10, value: 0.96, std: 0.018, num. features: 5, best value: 0.96
spFtSel-INFO: iter: 15, value: 0.956, std: 0.015, num. features: 5, best value: 0.96
spFtSel-INFO: iter: 20, value: 0.963, std: 0.012, num. features: 5, best value: 0.963
spFtSel-INFO: iter: 25, value: 0.953, std: 0.017, num. features: 5, best value: 0.963
spFtSel-INFO: iter: 30, value: 0.966, std: 0.014, num. features: 5, best value: 0.966
spFtSel-INFO: iter: 35, value: 0.963, std: 0.012, num. features: 5, best value: 0.968
spFtSel-INFO: iter: 40, value: 0.967, std: 0.011, num. features: 5, best value: 0.968
spFtSel-INFO: iter: 45, value: 0.961, std: 0.012, num. features: 5, best value: 0.968
spFtSel-INFO: iter: 50, value: 0.964, std: 0.021, num. features: 5, best value: 0.968
spFtSel-INFO: iter: 55, value: 0.963, std: 0.013, num. features: 5, best value: 0.972
spFtSel-INFO: iter: 60, value: 0.942, std: 0.019, num. features: 5, best value: 0.972
spFtSel-INFO: iter: 65, value: 0.934, std: 0.028, num. features: 5, best value: 0.972
spFtSel-INFO: iter: 70, value: 0.946, std: 0.018, num. features: 5, best value: 0.972
spFtSel-INFO: iter: 75, value: 0.94, std: 0.02, num. features: 5, best value: 0.972
spFtSel-INFO: spFtSel run completed.
Let's get the indices of the best features.
In [30]:
fs_indices_spsa = sp_output.get('features')
fs_indices_spsa
Out[30]:
array([27, 20, 21, 29, 10])
Let's have a look at the top 5 features selected by SPSA.
In [31]:
best_features_spsa = cancer_df.columns[fs_indices_spsa].values
best_features_spsa
Out[31]:
array(['worst_concave_points', 'worst_radius', 'worst_texture',
'worst_fractal_dimension', 'radius_error'], dtype=object)
In [32]:
feature_importances_spsa = sp_output.get('importance')
feature_importances_spsa
Out[32]:
array([1. , 1. , 0.93958984, 0.87910849, 0.85585522])
In [33]:
plot_imp(best_features_spsa, feature_importances_spsa, 'SPSA', 'brown')
Out[33]:
Finally, let's evaluate the performance of the SPSA feature selection method.
In [34]:
cv_results_spsa = cross_val_score(estimator=clf,
X=Data[:, fs_indices_spsa],
y=target,
cv=cv_method,
scoring=scoring_metric)
cv_results_spsa.mean().round(3)
Out[34]:
0.964
We observe that we get a cross-validation accuracy of 96.4% with SPSA with just 5 features. Recall that the cross-validation accuracy with the full set of features is 95.4%. So, in this particular case, it is remarkable that we can achieve even slightly better results with 5 features selected by SPSA as opposed to using all the 30 features. However, we will need to conduct a t-test to determine if this difference is statistically significant or not.
## Performance Comparison Using Paired T-Tests¶
For performance assessment, we used repeated cross-validation. However, cross-validation is a random process and we need statistical tests in order to determine if any difference between the performance of any two feature selection methods is statistically significant; or if it is within the sample variation and the difference is statistically insignificant.
Since we fixed the random state to be same for all cross-validation procedures, all feature selection methods were fitted and then tested on exactly the same data partitions. This indicates that our experiments were actually paired. Conducting experiments in a paired fashion reduces the variability significantly compared to conducting experiments in an independent fashion.
Let's now conduct paired t-tests to see which differences between full set of features, filter methods, and SPSA are statistically significant. Let's first remind ourselves the performances.
In [35]:
print('Full Set of Features:', cv_results_full.mean().round(3))
print('F-Score:', cv_results_fscore.mean().round(3))
print('Mutual Information:', cv_results_mutual_info.mean().round(3))
print('RFI:', cv_results_rfi.mean().round(3))
print('SPSA:', cv_results_spsa.mean().round(3))
Full Set of Features: 0.954
F-Score: 0.928
Mutual Information: 0.92
RFI: 0.92
SPSA: 0.964
For a paired t-test in Python, we use the stats.ttest_rel function inside the scipy module and look at the p-values. At a 95% significance level, if the p-value is smaller than 0.05, we conclude that the difference is statistically significant.
In [36]:
from scipy import stats
print(stats.ttest_rel(cv_results_spsa, cv_results_fscore).pvalue.round(3))
print(stats.ttest_rel(cv_results_spsa, cv_results_mutual_info).pvalue.round(3))
print(stats.ttest_rel(cv_results_spsa, cv_results_rfi).pvalue.round(3))
0.0
0.0
0.0
For SPSA vs. all the other three feature selection methods, we observe a p-value of 0, which indicates SPSA is statically better than F-score, mutual information, and RFI methods.
In [37]:
stats.ttest_rel(cv_results_spsa, cv_results_full).pvalue.round(3)
Out[37]:
0.06
For SPSA vs. full set of features, we observe a p-value of 0.06, indicating that the difference is not statically significant. Thus, SPSA with 5 features performs at similar levels as the full set of features, at least for the 1-nearest neighbor classifier.
Note: In this notebook, we use all the data to train the feature selection methods and then tested them again on the entire dataset using cross-validation. Despite its simplicity, this approach potentially results in overfitting. In order to mitigate this issue, a more appropriate procedure would be to perform this comparison within a repeated cross-validation scheme: we use two nested for loops (the outer loop for the repetitions and the inner loop for the folds). In the inner loop, we use a particular 80% of the entire data for fitting the feature selection methods and the remaining 20% for evaluation.
www.featureranking.com
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http://alex.nisnevich.com/blog/2018/09/15/plotting_land_use_maps.html
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(Or, the week I finally went off the hipster deep end)
About six months ago, I read Tobias Toft's excellent article "An intro to Pen Plotters". Inspired by the wonderful art he demonstrated, I set out to get my own plotter - a drawing robot from the pre-printer age - to play with.
This is the story of my first experiment with pen plotters – plotting a land-use map of Downtown Berkeley:
Setting up and using an HP 7475A plotter
I took Tobias's advice and took to eBay to look for HP 7xxx-series plotters. I found a cheap HP 7475A that looked to be in good condition, and eagerly awaited its arrival ... only to discover that I hadn't been careful enough in looking at the listing and that the plotter came with the dreaded HP-IB port:
I didn't know this at the time, but it turns out the that HP 7475A was one of the few HP pen plotters that came in two models: one with a forward-compatible serial port and one with a backward-compatible HP-IB port. Not having any idea what to do with this strange plug (it's not 1985 anymore, after all), I turned to the internet and discovered a post that began a sentence with "FWIW, if you have an HP-IB plotter, you should probably just hack an Arduino into the motor control connections..." Yikes, that's a bit more than I'd signed up for.
Fortunately, the eBay seller was understanding and let me return the HP-IB plotter. Eventually I managed to find an HP 7475A with a serial port. From there, I was able to follow Tobias's instructions. I got a null modem cable and a serial-to-USB converter cable and plugged the plotter into my Macbook.
I tested the plotter out by sending some commands over Coolterm, but found it pretty finicky. After trying a few different terminal emulators and plotting utilities, I discovered the excellent Chiplotle library, and have been using it ever since. For interactive plotting I load the chiplotle shell, and for quickly plotting HPGL files created separately I use the plot_hpgl_file.py script.
The first step to plotting a map is loading the appropriate shapefile in a GIS environment (I use the open-source QGIS) and exporting each desired layer as PDF. I followed the instructions in the "Preparing Data" section of the QGIS tutorial to load a map of Berkeley from OpenStreetMap:
From there, I exported a PDF for each layer I was interested in:
• roads.pdf is the set of lines (roads, train tracks, paths, etc) with labels removed
• comm.pdf is the union of the "commercial" and "retail" polygon layers
• inst.pdf is the "institutional" polygon layer (admittedly this layer doesn't have a lot in it)
• green.pdf is the union of the "farmland", "forest", "grass", and "recreational_ground" polygon layers
Initially I separately exported the "residential" layer as well, but I found that it cluttered up the map too much. There is also a layer consisting of all structures, which likewise would have been cool to use (in particular, it would have made the university grounds on the right side look less sparse) but likewise it caused too much clutter.
I selected each layer (or set of layers) in turn and exported to PDF (Project | Export to PDF), being careful to preserve the exact same dimensions and map coordinates between each PDF.
Converting PDF -> HPGL
Now that I had a bunch of PDFs, I needed to convert them to the HPGL format for plotting. I couldn't find any way to convert PDF -> HPGL in one operation, and settled for converting PDF -> PS using pdf2ps and PS -> HGPL using pstoedit.
I wrote a simple pdf2hpgl.sh script that, given a list of pairs of PDF file paths and pen numbers (for example, pdf2hpgl.sh roads.pdf 3 comm.pdf 5 inst.pdf 4 green.ps 2), converts each PDF file into an HPGL file, changes all SP (select pen) commands to use the given pen number (instead of the more-or-less random pen selections made by pstoedit), and concatenates the result together into one big HPGL file:
And voila, we now have an HPGL file that we can send directly to the plotter.
Here's what it looks like with just the roads layer plotted:
Unfortunately, the polygon layers don't end up looking very good when simply overlaid on top of the roads layer (I neglected to take a photo of this; you'll have to take my word for it), since they're just rectangular outlines that are difficult to see next to the black lines of the roads.
If we want to display the land-use layers in a legible way, we'll need to get a little creative. How about turning those polygons into hatching lines?
I decided to use Adobe Illustrator to generate the hatching lines, but me not being an Illustrator expert by any means, I spent many hours fruitlessly trying different tools to no avail. The issue was that I needed to create a PS file with just the lines themselves – no hatching patterns defined, no masking layers – because the HPGL dialect spoken by the HP 7475A (as opposed to the later, more sophisticated HP-GL/2) doesn't support any of these fancy features.
I finally gave up on figuring this out on my own, and asked Stack Exchange, where I got my answer.
The workflow I finally settled on is a bit convoluted, but it does work:
• Load the PS file corresponding to a single layer in Illustrator (using pdf2ps to generate the PS from the QGIS PDF export).
• Remove the background layer to leave just the layer with the polygon paths.
• Select the remaining layer. If there are multiple paths, use Pathfinder | Unite.
• With the layer still selected, create a compound path with Object | Compound Path | Make.
• Fill the path with a pattern I made of diagonal strokes, and remove the stroke outline.
• Adjust the spacing of the hatching lines as desired with Object | Transform | Scale (with only "Transform Patterns" checked).
• Convert the compount path to a group of hatching lines with Object | Expand and then Object | Path | Outline Stroke.
• Select everything and click Pathfinder | Crop in the Properties panel.
• Finally, export the result back to PS by printing to Postscript using the "Device Independent" PPD. I then converted the PS file to HPGL using a modified version of my pdf2hpgl.sh script that simply skips the pdf2ps step.
Here's what it looks like when I plot the resulting hatch lines for just one layer (the "commercial" layer):
Once we have hatching for one layer working, we can do the rest of them just by repeating the process for each layer. I did have to carefully align each layer together in Illustrator (and then print them out to Postscript one at a time by selectively hiding layers):
That said, you can create some cool glitchy art by neglecting to properly align the layers:
The Final Product
I ran plot_hpgl_file.py and crossed my fingers. After 10 minutes of meticulous plotting, the map came out of the plotter, and actually looked halfway decent. I added some text and carefully cut the paper from 11"x17" to 11"x14" to reduce the amount of unsightly white space at the bottom:
Not perfect, but it's certainly not bad for a week's work.
I haven't had the chance to do much else with the pen plotter yet, but hopefully this gave you a taste of what these little robots can do. And who knows, maybe I can inspire someone else to save a plotter from a junkyard, like Tobias Toft's article inspired me. (Just watch out for the dreaded HP-IB port...)
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https://tel.archives-ouvertes.fr/tel-02447312
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# Measurement of jet properties in pp and Pb-Pb collisions at 5.02 TeV with the ALICE experiment at the LHC
Abstract : Jets, defined as collimated sprays of high-momentum particles, are experimental signatures of hard-scattered quarks and gluons produced in hadronic interactions. The jet production cross section is calculable within perturbative Quantum ChromoDynamics (pQCD), and therefore jet measurements provide stringent tests of pQCD predictions. In relativistic heavy-ion collisions, jets are well calibrated probes of the Quark-Gluon Plasma (QGP). Under extreme conditions of temperature and/or pressure, partons are deconfined and form a strongly interacting QCD medium. The initial hard scattered partons lose energy while traversing this medium due to radiative and collisional energy loss. Consequently, jet properties get modified in comparison with the vacuum case, phenomenon named jet quenching. QGP transport properties can be studied by measuring jet quenching.The charged jet production cross sections in pp collisions at √s = 2.76TeV and √s = 7TeV were measured by the ALICE experiment and compared to Leading-Order (LO) pQCD predictions. In Pb-Pb collisions, the strength of jet suppression was quantitatively assessed at √{s_NN} = 2.76TeV and √{s_NN} = 5.02TeV via the measurement of the nuclear modification factors (R_AA). The strength of charged jet suppression was quantified as a function of in-medium parton path-length based on the measured R_AA. The jet elliptic flow v₂, defined as the jet azimuthal distribution relative to the 2^{nd} order event plane, which is sensitive to the difference of the in-medium parton path-length in-plane and out-of-plane, was measured at √{s_NN} = 2.76TeV. The measured jet v₂ in mid-central Pb-Pb collisions was consistent with model predictions. The medium response has been studied through jet-track correlations at √{s_NN} = 2.76TeV as a function of centrality. The result suggested that the in-medium suppressed energy was re-distributed to large angles with respect to the jet axis. The phenomenon was described by a phenomenological calculation taking into account hydrodynamical evolution of the medium.In this thesis, two complementary aspects of jet measurements with the ALICE detector at the LHC were studied. First, the upgrade of the ALICE electromagnetic calorimeter trigger system is presented. The Di-jet Calorimeter (DCal) has been installed during LHC Long Shutdown 1 (LS1) to extend the azimuthal coverage of the existing ElectroMagnetic Calorimeter (EMCal) and PHOton Spectrometer (PHOS). The trigger system has been upgraded to account for this new detector configuration. The firmware for the Summary Trigger Unit (STU), which is the electronics of the trigger system, was upgraded to implement a brand new algorithm combining information from the calorimeters. Second, the measurement of the production cross section of charged jets reconstructed with cone resolution parameter R=0.2, 0.3, 0.4, and 0.6 in pp collisions at √s = 5.02TeV is outlined. A comparison of the production cross section to LO and Next-Leading-Order (NLO) pQCD predictions is shown. Good agreement of the production cross section with NLO pQCD calculations is found for 10 ≺ p_{T,jet}^{ch} ≺ 100GeV/c. The measurement of charged jet v₂ in mid-central (30-50%) Pb-Pb collisions at √{s_NN} = 5.02TeV is also presented. The results are compared with a toy-model Glauber simulation based on the measured path-length dependence of jet suppression. Finally, the measurement of charged jet-hadron correlations in mid-central (30-50%) Pb-Pb collisions at √{s_NN} = 5.02TeV with respect to the 2^{nd} order event plane is also presented in order to study initial collision geometry dependence of jet modification in Pb-Pb collisions.
Keywords :
Document type :
Theses
Cited literature [98 references]
https://tel.archives-ouvertes.fr/tel-02447312
Contributor : Abes Star : Contact
Submitted on : Tuesday, January 21, 2020 - 3:13:21 PM
Last modification on : Thursday, November 19, 2020 - 12:59:12 PM
### File
HOSOKAWA_2019_diffusion.pdf
Version validated by the jury (STAR)
### Identifiers
• HAL Id : tel-02447312, version 1
### Citation
Ritsuya Hosokawa. Measurement of jet properties in pp and Pb-Pb collisions at 5.02 TeV with the ALICE experiment at the LHC. High Energy Physics - Experiment [hep-ex]. Université Grenoble Alpes; Université de Tsukuba, 2019. English. ⟨NNT : 2019GREAY025⟩. ⟨tel-02447312⟩
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https://www.physicsforums.com/threads/implicitly-differentiating-pde-multivariable-calculus.271249/
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# Homework Help: Implicitly differentiating PDE (multivariable calculus)
1. Nov 11, 2008
### Legion81
The problem:
Find the value of dz/dx at the point (1,1,1) if the equation xy+z3x-2yz=0 defines z as a function of the two independent variables x and y and the partial derivative exists.
I don't know how to approach the z3x part. I thought you would use the product rule and get 3(dz/dx)2x + z3. But if that is right, the final equation looks something like
y + 3x(dz/dx)2 + z3 - 2y(dz/dx) = 0
And I don't think that is right. The only way I know to solve that would be with the quadratic equation and that gives a complex value. Am I forgeting the chain rule somewhere or just way off on approaching this problem?
1. The problem statement, all variables and given/known data
2. Relevant equations
3. The attempt at a solution
2. Nov 11, 2008
### Frillth
I have done very little multivariable so this could easily be wrong, but if you implicitly differentiated z^3x shouldn't you get 3z^2x*dz/dx + z^3?
3. Nov 11, 2008
### Legion81
That's right because you have the 3z2x(dz/dx) + z3(dx/dx). I don't know what I was thinking... Thank You!
4. Nov 11, 2008
### ducnguyen2000
You didn't apply the chain rule, remember df(u)/dx = f(u)'*du/dx
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https://math.answers.com/Q/Can_the_product_of_two_numbers_be_less_than_either_of_the_numbers
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0
# Can the product of two numbers be less than either of the numbers?
Wiki User
2010-10-04 20:00:52
If one of the numbers is negative, but the other is positive, then the product is negative - and therefore smaller than both numbers in the question. For example, 2 x -4 = -8.
=====================================
Also, whenever the absolute magnitude of both factors is less than ' 1 ',
the absolute magnitude of the product is less than either factor.
Wiki User
2010-10-04 20:00:52
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http://crypto.stackexchange.com/users/2325/malice?tab=activity
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Malice
Reputation
Top tag
Next privilege 15 Rep.
Flag posts
Jun 20 comment Regarding matsui's Paper on Linear Cryptanalysis of DES Oh yes i get it . It's same as the other equation if you reduce the first two terms Jun 20 comment Regarding matsui's Paper on Linear Cryptanalysis of DES While expanding this Equation to a single round of DES, the Output of the function f is XORed with plain text . How does this equation we're talking about hold true because plain text is of random content but Matsui says this equation holds true $X_{2}[7,8,24,29]\bigoplus P_H[7,18,24,29]\bigoplus P_{L}[15]=K_{1}[22]$ Jun 20 comment Regarding matsui's Paper on Linear Cryptanalysis of DES Oh My mistake . I's counting bits starting from left handside and was getting a differnt expression,should start counting from right hand side . Spent hours trying to find this .A bucketfull of thanks Jun 20 awarded Scholar Jun 20 accepted Regarding matsui's Paper on Linear Cryptanalysis of DES Jun 20 awarded Editor Jun 20 comment Regarding matsui's Paper on Linear Cryptanalysis of DES And please note that it's $NS_{5}(16,15)$ not $NS_{5}(16,5)$ . Typo . I've edited the Question Jun 20 revised Regarding matsui's Paper on Linear Cryptanalysis of DES deleted 1 characters in body Jun 20 comment Regarding matsui's Paper on Linear Cryptanalysis of DES Exactly . But I'm looking for is how did he manage the 1 round linear approximation from the $NS_{5}(16,15)$ equation . He did not describe that in the paper and nor can i find it anywhere on internet Jun 19 awarded Student Jun 17 comment Regarding matsui's Paper on Linear Cryptanalysis of DES Please find the paper at www.cs.bgu.ac.il/~crp042/Handouts/Matsui.pdf Jun 16 asked Regarding matsui's Paper on Linear Cryptanalysis of DES
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https://www.physicsforums.com/threads/find-the-minimal-distance-between-any-point-on-the-sphere.270042/
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# Find the minimal distance between any point on the sphere
1. Nov 7, 2008
### helix999
How can we find the minimal distance between any point on the sphere whose centre is 2,1,3 and radius is 1 and any point on the sphere centred at -3,2,4 and radius is 4?
is there any formula for finding this minimum distance ?
2. Nov 7, 2008
### aniketp
Re: spheres
find the distance between the centres, and subtract the sum of radii of the spheres....
3. Nov 7, 2008
### helix999
Re: spheres
thnx aniketp...that was helpful...i got my answer
4. Nov 7, 2008
### aniketp
Re: spheres
no problem, but i hope you understood WHY this works.
5. Nov 7, 2008
### helix999
Re: spheres
well...yes...i have a math exam tomorrow....have to finish a LOT of things
Have something to add?
Similar Discussions: Find the minimal distance between any point on the sphere
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https://destevez.net/2019/04/diffraction-in-dslwp-b-lunar-occultations/
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# Diffraction in DSLWP-B lunar occultations
In February this year, the orientation of the orbit of DSLWP-B around the Moon was such that, when viewed from the Earth, it passed behind the Moon on every orbit. This opened up the possibility for recording the signal of DSLWP-B as it hid behind the Moon, thus blocking the line of sight path. The physical effect that can be observed in such events is that of diffraction. The power of the received signal doesn’t drop down to zero in a brick-wall fashion just after the line of sight is blocked, but rather behaves in an oscillatory fashion, forming the so called diffraction fringes.
The signal from DSLWP-B was observed and recorded at the Dwingeloo 25m radiotelescope for three days in February: 4th, 13th and 15th. During the first two days, an SSDV transmission was commanded several minutes before DSLWP-B hid behind the Moon, so as to guarantee a continuous signal at 436.4MHz to observe the variations in signal power as DSLWP-B went behind the Moon. On the 15th, the occultation was especially brief, lasting only 28 minutes. Thus, DSLWP-B was commanded to transmit continuously before hiding behind the Moon. This enabled us to also observe the end of the occultation, since DSLWP-B continued transmitting when it exited from behind the Moon. This is an analysis of the recordings made at Dwingeloo.
The recordings can be found here. I have used my Moonbounce processing scripts to compute the signal power from the recordings. These scripts were made to study the power of the Moonbounce signal, but can be used here as well. Essentially, the script performs Doppler correction using the tracking files published in dslwp_dev as orbit state vector and GMAT as propagator, detects the frequency offset of the GMSK signal from DSLWP-B, lowpass filters it, and takes averaged power readings in windows of 102.4ms.
The occultations were planned as shown in this post. After computing the expected times of the occultations, the relevant segments of the power readings are plotted, obtaining the figures shown below.
The first two figures correspond to the start of the occultations on February 4 and 13. The last two figures correspond to the start and end of the occultation on Februrary 15. The first figure looks somewhat different from the rest because the occultation was much slower. Take note at the time axis.
We can clearly see the diffraction fringes. Before dropping down to zero, the power of the received signal oscillates. The diffraction pattern that happens during a lunar occultation is explained in this document. There, the case of study is the occultation of a star by the Moon at optical wavelengths. In the derivation done in that document, it is implicitly assumed that the star is very far, so the wave arriving the Moon can be assumed to be a plane wave. This is not the case for DSLWP-B, which is much more near to the Moon. In this case, we need to consider a point source instead of a plane wave. The same kind of diffraction pattern is obtained in both cases, but the temporal frequency at which the diffraction fringes occur (the fringe rate) can be quite different, especially because the distance from DSLWP to the surface of the Moon is changing quickly.
The typical diffraction pattern is given by the Fresnel integral$D(\nu) = \frac{1}{2}\left|\int_{-\infty}^\nu e^{i\pi s^2/2}\,ds\right|^2.$A plot of this function can be seen in the figure below.
The variable $$\nu$$, depends on the geometry of the diffraction, and is computed differently in the case of a plane wave or a point source. The point $$\nu=0$$ represents the case of a grazing diffraction, which means that the line of sight path is tangent to the obstacle. The case $$\nu < 0$$ corresponds to the situation when the direct line of sight is blocked, and $$\nu > 0$$ corresponds to the situation when there is a direct line of sight path. As the obstacle gets away from the line of sight and $$\nu \to +\infty$$, we have $$D(\nu) \to 1$$, so we recover the power we would have if the obstacle wasn’t present.
Without discussing for now much about the geometry of the problem and how to compute $$\nu$$ with respect to time $$t$$, we just assume that it is reasonable to approximate $$\nu$$ by its first order Taylor expansion about the instant $$t_0$$ when the grazing diffraction happens:$\nu \approx v(t-t_0).$
The next step in the analysis is to fit a function of the form$P_0D(v(t-t_0))$to the observed data, where $$P_0$$, $$v$$, and $$t_0$$ are unknown parameters representing the unobstructed signal power, the fringe rate, and the instant of grazing respectively.
To that end, we use a non-linear least squares fit. It is important to choose the initial values for the unknown parameters correctly to avoid falling in a local minimum. We do the following educated guesses. For $$t_0$$ we take the instant when the power achieves its average value. To estimate $$v$$ we try to locate the first local minimum and maximum of the diffraction fringes and compute $$v$$ in terms of their temporal spacing. Finally, $$P_0$$ is estimated as the mean value of the power after the first local minimum. The time interval over which the fit is performed is selected by hand. Also, averaging of the data is performed for the first occultation.
After taking these precautions, the fit is rather good, as shown in the figures below.
The fit gives us empirical values for $$t_0$$ and $$v$$. Let us compare those with the theoretical values obtained by using the tracking files from dslwp_dev as ephemeris and propagating the orbit in GMAT. This requires us to speak about how $$\nu$$ is computed in terms of the geometry, for the case of a point source.
This is treated in this text very succinctly. It states that$\nu = \pm2\sqrt{\frac{\Delta}{\lambda}},$where $$\lambda$$ is the wavelength and $$\Delta$$ is the difference in distances between a certain “reflected” path and the direct line of sight path. The sign $$\pm$$ is chosen according as to whether the direct line of path is blocked or not, as explained above.
In more detail, assume that our transmitter and receiver are at points $$A$$ and $$B$$ respectively. Consider the point $$R$$ in the obstacle that is closest to the line segment joining $$A$$ and $$B$$. Then $\Delta = \|A-R\| + \|R-B\| – \|A-B\|,$ where $$\|P-Q\|$$ denotes the distance between the points $$P$$ and $$Q$$. Thus, $$\Delta$$ is the extra distance traveled by a ray that goes from $$A$$ to $$B$$ reflecting off $$R$$.
As an interesting fact, we have that the time derivative $$d\Delta/dt$$ is equal to the difference in Dopplers between the direct signal and the Moonbounce signal (see the Appendix in this post). However, we are not really interested in $$d\Delta/dt$$ but rather in the time derivative of $$\nu$$, which involves $$\sqrt{\Delta}$$, so it is not easy to relate the fringe rate and the Doppler directly.
In the case of the lunar occultation of DSLWP-B, we compute $$\Delta$$ as follows. From GMAT we get the coordinates of the points $$A$$ and $$B$$ corresponding to DSLWP-B and Dwingeloo, and $$M$$, which corresponds to the centre of the Moon. We compute the distance $$\delta$$ between $$M$$ and the line passing through $$A$$ and $$B$$ by computing $l = \frac{\langle M – B, A – B\rangle}{\|A-B\|},$the projection of the vector joining Dwingeloo and the Moon onto the unit line of sight vector pointing from Dwingeloo to DSLWP-B. Then$\delta = \sqrt{|M-B|^2 – l^2}.$We note that$\Delta = |\delta – r|,$where $$r$$ is the lunar radius, and that the sign of $$\nu$$ coincides with the sign of $$\delta – r$$.
The instant of grazing diffraction is found by locating the time $$t_0$$ for which $$\Delta = 0$$. Then, the time derivative $$\frac{d\nu}{dt}(t_0)$$ is evaluated numerically as a difference quotient.
For each of the four diffractions studied in this post, we obtain the following time differences in seconds between the instant of grazing $$t_0$$ obtained from the fit to the measurements and the GMAT simulation:
[-116.05367306500001, 13.311127206, 31.371431057000002, 41.360679158]
We see that there are errors on the order tens of seconds. This can be explained by errors in the ephemeris. Indeed, it is difficult to estimate the mean anomaly of the orbit accurately, and it is the first parameter that becomes inaccurate with time, since orbital perturbations always build up in the mean anomaly. An offset in mean anomaly translates directly into a time offset in the instant of grazing. Determining accurately the instant of grazing is actually a good way to measure the mean anomaly precisely.
It is also interesting to observe the last two time differences, which correspond to the entry and exit of the same occultation on February 15. They have a difference of 10.01s, meaning that the duration of the occultation had such a difference between the observations and the GMAT prediction. This could also be explained by ephemeris errors, but the situation is not as simple as an offset in the mean anomaly.
The relative errors in the calculation of the fringe rate $$\frac{d\nu}{dt}(t_0)$$ between the observations and the GMAT prediction are shown below in parts per one:
[0.012628611461853678, -0.14849525967852584, 0.03838583537440288, 0.021923209485447237]
We observe errors between 1% and 15%. This means that our model for the geometry of the diffraction explains the observations very well.
The grazing instants determined from the observations are
2019-02-04T10:06:58.3454239352019-02-13T21:31:11.2576072062019-02-15T14:23:36.4204000572019-02-15T14:51:46.844356158
The fringe rates, in units of 1/s determined from the observations are
[-0.1682628343896966, -1.2532957532402556, -1.7370407299575834 1.6895344971498276]
The computations and plots shown in this post have been done in this Jupyter notebook.
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https://math.stackexchange.com/questions/1207793/collection-of-spanning-trees-for-a-simple-connected-graph
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# Collection of spanning trees for a simple connected graph
Consider a graph $G$ whose edges are labelled $\{1, 2, ..., k\}$. Then the set of spanning trees is a collection of subsets of $[k]$.
a) Let $T$ = $\{\{1,2\}, \{1,3\}, \{1,4\}, \{2,3\}\}$. Can $T$ be the collection of spanning trees of a simple connected graph?
b) Let $2\leq{n}$. Consider the collection $U_{2,n}$ of subsets of $[n]$ of size $2$. For what values of $n$ is $U_{2,n}$ the collection of spanning trees of a a connected graph?
To be honest I'm confused as to what these questions are asking in the first place. The numbers in $T$ refer to actual edges (so edges are labelled $1, 2, ...$ , not the edge between vertices $1$ and $2$, etc.)
If a graph has 4 edges and is simple and connected, then it can either have 4 or 5 vertices, right? Then does that mean $T$ does contain all the spanning trees of a specific graph since every edge is covered in there? For instance say I have a graph $G=(V,E)$ where I have $V$={a, b, c, d, e} and edge 1 = (a,b), edge 2= (a, c), edge 3 = (a, d), and edge 4 = (d, e). Technically the only spanning tree would be itself, right?
*I could even have the graph have edges 1=(a,b), 2=(b, c), 3=(c,d), 4=(d, e) and the only spanning tree would be one containing all edges.
Am I completely missing the point of this question? I'm so confused.
As I've used it, the definition of a spanning tree is a tree that contains all the vertices in some graph, not the edges. In this case, for a), $T$ cannot be the collection of spanning trees because not every member of $T$ can be a spanning tree. We can assume that our graph $G$ has four nodes (no simple graph of three nodes can have four edges and it's not possible to span five nodes with two edges). For example, if $(1,2)$ is a spanning tree, then $(1,3)$ cannot be one because given that $G$ is simple, $2 \ne 3$.
Regarding b), $U_{2,n}$ may contain all spanning trees for higher values of $n$, but for $U_{2,n}$ to strictly equal the set of spanning trees of a connected graph, $n \le 3$.
• I see, I guess I wasn't looking at the set as each {1, 2} etc. being its own spanning tree. I thought maybe you could just take all the elements of $T$ but thinking about it now each element {i,j} standing for a possible spanning tree makes more sense. Thanks! – Karen M. Mar 27 '15 at 3:03
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http://mathhelpforum.com/calculus/17300-r-2cos-theta-graph.html
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1. ## r=2cos theta graph
Could you please tell me how to plot r=2cos theta ? Please show me the step of plotting this graph. Thanking in advance.
2. Originally Posted by kittycat
Could you please tell me how to plot r=2cos theta ? Please show me the step of plotting this graph. Thanking in advance.
Decide on a set of $\theta$ values, say,
$\theta = 0, \pi/4, \pi/2, 3\pi/4, pi, 5pi/4, 3\pi/2, 7\pi/4$ rad
Then calculate the r value for each $\theta$. They are
$r = 2, \sqrt{2}, 0, -sqrt{2}, -2, -\sqrt{2}, 0, \sqrt{2}$ (respectively)
What do you do with negative r values? Well, you make the r value positive and then add (or subtract) $\pi$ rad to the angle.
So we wish to plot the set of points:
$(r, \theta)$
$(2, 0)$
$(\sqrt{2}, \pi/4)$
$(0, \pi/2)$
$(\sqrt{2}, 5\pi/4)$
$(2, 0)$ <-- $\pi + \pi = 2\pi \to 0$
$(\sqrt{2}, \pi/4)$
$(0, 3\pi/2)$
$(\sqrt{2}, 7\pi/2)$
Then you plot the points on polar coordinate graph paper and sketch in a smooth curve between the points. I get the graph below.
-Dan
Attached Thumbnails
3. Originally Posted by kittycat
Could you please tell me how to plot r=2cos theta ? Please show me the step of plotting this graph. Thanking in advance.
Or you could do it the hard way:
$r = \sqrt{x^2 + y^2}$
$cos(\theta) = \frac{x}{\sqrt{x^2 + y^2}}$
$\sqrt{x^2 + y^2} = 2 \frac{x}{\sqrt{x^2 + y^2}}$
Multiplying both sides by $\sqrt{x^2 + y^2}$ gives:
$x^2 + y^2 = 2x$
$(x^2 - 2x) + y^2 = 0$
$(x^2 - 2x + 1) + y^2 = 1$
$(x - 1)^2 + y^2 = 1$
which is a circle centered on (1, 0) with radius 1.
-Dan
4. Sorry, i saw you used polar functions, my apologies. I'll delete my posts now.
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# graph of 2 cos theta
Click on a term to search for related topics.
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https://www.physicsforums.com/threads/wilson-theorem-and-formulas-for-pi-x.118199/
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# Wilson theorem and formulas for pi(x)
1. Apr 20, 2006
### eljose
Hello..my question is from wilson theorem:
$$(p-1)!=-1mod(p)$$
how could you derive the formulae for $$pi(x)$$?..this should be impossible as you can,t solve the congruence exactly a proposed method would be to find the roots of:
$$f(x)=[\gamma(x)+1/x]-(\gamma(x)+1)/x$$
that precisely x=p for every prime and intege...
2. Apr 20, 2006
### matt grime
Do you not feel the slightest desire to define gamma?
3. Apr 20, 2006
Nor to use proper English sentences?
I mean what the hell is a "root of [equation] such that precisely x=p for every prime and intege..."
Last edited: Apr 20, 2006
4. Apr 21, 2006
### eljose
-Umm..sometimes i don,t know if you,re speaking seriously or if this some kind of British-American sarcastic humour:
$$\Gamma(x)=\int_{0}^{\infty}dxt^{x-1}e^{-t}$$
a "root" is just a root in the sense that is a number that satisfies for some function that f(c)=0 then c is a root of the function. for the primes and using Wilson,s theorem we would have that
$$Sin(\pi[\Gamma(x)+1]/x)=0$$ iff x is p for p prime.
and using this "Gamma" function Wilson,s theorem becomes
$$\Gamma(p)+1=0mod(p)$$ but how can you obtain the Prime number counting function from wilson,s theore?..thanks.
Last edited: Apr 21, 2006
5. Apr 21, 2006
### matt grime
it is weariness at seeing you repeatedly post articles that contain contradictory notation (using n for two different things in one equation for instance), symbols that you simply do not explain and careless abuse of mathematics: notice how your gamma is now an uppercase gamma when it started off as a lower case one.
notice how this produces a real number, for real x...
Does it? In what sense does it become this, since mod p is not something that makes sense for the real numbers? What is the point of introducing the gamma function if you can only use it for certain values in the domain where we already have a better description of its value (at these points)? So, what good does introducing the gamma function do? You can't use it, can you? No arguments, that (p-1)! is indeed Gamma(p), and that Wilson's theorem is that p-1!=-1 mod p, but why use Gamma instead of p-1!? The proof of Wilson's theorem is not one that uses real analysis, so why do this?
Last edited: Apr 21, 2006
6. Apr 21, 2006
### shmoe
$$\gamma$$ and $$\Gamma$$ look different to me, we aren't mind readers.
see http://mathworld.wolfram.com/PrimeFormulas.html (3)-(5) show how to get pi(x) using Wilson's theorem. Wilson's theorem is not at all practical for computing pi(x) like this, nor for locating primes by looking at zeros of that sin function. n! grows too fast. Besides, the version you have with real numbers for x in $$\sin (\pi(\Gamma(x)+1)/x)$$ has zeros at many real numbers that aren't prime integers.
Last edited: Apr 21, 2006
7. Apr 22, 2006
### eljose
the main question is not computing a prime this was not my intention..but perhaps to throw some of light into the problem of time primes in fact for m and m+2 twin primes:
$$4((m-1)!+1)+m=0mod(m(m+2)$$ so we could compute the density of twin primes in the form:
$$\pi_{2}(m)=\sum_{2}^{m}cos^{2}[\pi([4((m-1)!+1)+m/(m+2)m]-4((m-1)!+1)+m/(m+2)m)$$
if somehow we could invert this twin prime counting function t obtai the k-th twin prime in the form:
$$p_{n}=C+\sum_{k=2}^{f(n)}F(k,\pi_{2}(k))$$ we could prove that p-n is not bounded for p a twin prime so it must be an oo number of them.
8. Apr 22, 2006
### shmoe
If you mean something essentially like (3)-(5) from that link, then sure. What you have here has a few errors in the parenthesis so it's hard to tell what you mean. You would also want the floor of the cos terms at some point, otherwise this is most likely not even an integer.
You can do essentially the same as (10)-(11) from the mathworld link. As in the case of primes, this isn't a very enlightening expression, it's mostly a novelty.
9. Apr 22, 2006
### eljose
-I think that the "cos" term is enclosed by a floor function [cos] o this only can be 1 or 0.
-If wemanaged in the same case that for ordinary primes to prove that the k-th twin prime is:
$$p_{k}=\sum_{n=2}^{f(k)}G(n,\pi_{2}(n)+C$$
we would have proved "twin prime conjecture" as there would be the (k+1)-th prime so:
$$p_{k+1}-p_{k}=\sum_{f(k)}^{f(k+1)}G(n,\pi_{2}(n))+C$$
this formula somehow would use the [] function as the difference would be an integer so if this sum is $$p_{k+1}-p_{k}>0$$ then for every k exist a higher prime (k+1) wich is the next twin prime in the series.
10. Apr 22, 2006
### shmoe
Which we can do. If you have the counting function of a sequence, (10)-(11) can be used to give you the nth term of the sequence. However:
This isn't true. Using that expression to show there are in fact infinitely many twin primes will rely on already knowing that $$\pi_2(x)$$ goes to infinity as x does, i.e. you already need to know there are infinitely many twin primes.
Try using the formula from Hardy&Wright ((10)-(11) in the link) to prove there are infinitely many primes without already knowing that pi(x)->infinity as x->infinity (edit-more specifically, try proving that the p_n defined by this formula are in fact prime without already knowing there are infinitely many primes)
Last edited: Apr 22, 2006
11. Apr 23, 2006
### eljose
-umm...i see in this form (perhaps wrong) if we have the formula:
$$p_{k+1}-p_{k}=\sum_{f(k)}^{f(k+1)}G(n,\pi_{2}(n))+C$$
this means that for every k-th twin prime there is another consecutive (k+1)-th prime no matter what k is of course if the number of twin primes is finite you have that the maximum value of $$\pi_{2}(n)=a$$ your only chance for having a finite number of primes is that somehow the function inside the sum including the floor function would be <1 and form tis we could perhaps calculate the last twin prime so either there are infinite number of twin primes or the last number can be calculated.
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https://www.physicsforums.com/threads/conditional-expectation.636636/
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# Conditional Expectation
1. Sep 17, 2012
### Scootertaj
1. Let the joint pdf be f(x,y) = 2 ; 0<x<y<1 ; 0<y<1
Find E(Y|x) and E(X|y)
2. Relevant equations
E(Y|x) = $\int Y*f(y|x)dy$
f(y|x) = f(x,y) / f(x)
3. The attempt at a solution
f(x) = $\int 2dy$ from 0 to y = 2y
f(y|x) = f(x,y)/f(x) = 1/2y
E(Y|x) = $\int Y/2Y dy$ from x to 1 = $\int 1/2 dy$ from x to 1
= -(x-1)/2
= (1-x)/2
The answer is supposed to be (1+x)/2
2. Sep 17, 2012
### jbunniii
Your expression for f(x) is wrong. It should be a function of x, not of y. Try drawing a picture of the region where f(x,y) is nonzero. Then answer this question: for a fixed value of x, what values of y will give you a nonzero f(x,y)?
3. Sep 17, 2012
### Scootertaj
The only other way I can think of doing f(x) would be to integrate from 0 to 1 instead. f(x) is defined as the integral of the joint pdf in terms of y.
So, we could get integral(2dy) from x to 1?
4. Sep 17, 2012
### jbunniii
Correct, from x to 1 (not as 0 to 1 as you wrote in the previous paragraph). Also be sure to state which values of x this is valid for.
5. Sep 17, 2012
### Scootertaj
That will give us 2(1-x) so f(y|x) = 1/(1-x)
I'm confused how this will give (1+x)/2 for E(y|x)
6. Sep 17, 2012
### Scootertaj
Just kidding I worked it out, thanks.
7. Sep 17, 2012
### jbunniii
That's the answer I got. What integral are you calculating for E(y|x)?
Cool, I see you got it.
Similar Discussions: Conditional Expectation
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http://mathhelpforum.com/geometry/205148-ladder-problem.html
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# Math Help - ladder problem
There are 2 ladders, one is 25 ft long the other is 20 ft long, they are crossing eachther in an alley between two buildings, find the distance between the two buildings. The point where the ladders intersect to the ground is 10 ft.
I would let the width of the alley be x, where $0. Drop a vertical line down from the point where the ladders meet to the ground. Let the horizontal distance from the left wall to the vertical line be $x_1$ and the horizontal distance from the vertical line to the right wall be $x_2$, hence:
$x_1+x_2=x$
Now, by similarity (and the Pythagorean theorem), we find:
$x_1=\frac{10x}{\sqrt{20^2-x^2}}$
$x_2=\frac{10x}{\sqrt{25^2-x^2}}$
Now solve for x.
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http://papers.nips.cc/paper/6545-consistent-kernel-mean-estimation-for-functions-of-random-variables
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# NIPS Proceedingsβ
## Consistent Kernel Mean Estimation for Functions of Random Variables
[PDF] [BibTeX] [Supplemental] [Reviews]
### Abstract
We provide a theoretical foundation for non-parametric estimation of functions of random variables using kernel mean embeddings. We show that for any continuous function f, consistent estimators of the mean embedding of a random variable X lead to consistent estimators of the mean embedding of f(X). For Matern kernels and sufficiently smooth functions we also provide rates of convergence. Our results extend to functions of multiple random variables. If the variables are dependent, we require an estimator of the mean embedding of their joint distribution as a starting point; if they are independent, it is sufficient to have separate estimators of the mean embeddings of their marginal distributions. In either case, our results cover both mean embeddings based on i.i.d. samples as well as "reduced set" expansions in terms of dependent expansion points. The latter serves as a justification for using such expansions to limit memory resources when applying the approach as a basis for probabilistic programming.
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https://mathhelpboards.com/threads/proof-of-a-linear-transformation-not-being-onto.6580/
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# Proof of a linear transformation not being onto
#### baseball3030
##### New member
Sep 18, 2013
9
proof onto
Prove: A linear Map T:Rn->Rm is an onto function :
The only way I have thought about doing this problem is by proving the contrapositive:
Last edited:
#### ModusPonens
##### Well-known member
Jun 26, 2012
45
Prove: A linear Map T:Rn->Rm is not onto if m>n.
The only way I have thought about doing this problem is by proving the contrapositive:
If m<=n then T:Rn->Rm is onto.
I would start by letting there be a transformation
matrix with dimension mxn.
Then the only thing I can think of doing is using the rank nullity thm to show that the dimension of the range=dimension of v. Does anyone know of any other ways to go about this or if my way would be correct? Thank you so much
The counterpositive is "If T is onto, then m<=n" It's easier to do it by the theorem that says that the dimensions of the kernel and of the image of T add to n.
#### Deveno
##### Well-known member
MHB Math Scholar
Feb 15, 2012
1,967
You can do a direct proof, and I do not think one needs to invoke rank-nullity.
let $B = \{v_1,\dots,v_n\}$ be a basis for $\Bbb R^n$.
Consider the set $T(B) \subset \Bbb R^m$.
If $u \in T(\Bbb R^n) = \text{im}(T)$ we have:
$u = T(x)$ for some $x = c_1v_1 + \cdots + c_nv_n \in \Bbb R^n$.
Thus:
$u = c_1T(v_1) + \cdots c_nT(v_n)$, which shows $T(B)$ spans $\text{im}(T)$.
Since $|T(B)| \leq n < m$, we have that the dimension of $\text{im}(T) \leq n < m$.
However, if $\text{im}(T) = \Bbb R^m$, we have that $T(B)$ spans $\Bbb R^m$ leading to:
$m \leq |T(B)| \leq n < m$, a contradiction.
As a general rule, functions can, at best, only "preserve" the "size" of their domain, they cannot enlarge it. Dimension, for vector spaces, is one way of measuring "size".
While it is technically possible to have a function from $\Bbb R^n \to \Bbb R^m$ where $m > n$ (so called "space-filling functions") that is onto, such functions turn out to be rather bizarre and cannot be linear (they do not preserve linear combinations). Linear maps cannot "grow in dimension", for the same reason the column rank cannot exceed the number of rows in a matrix (even if we have more columns than rows).
#### baseball3030
##### New member
Sep 18, 2013
9
How are you able to say that
Since |T(B)|≤n<m , we have that the dimension of im(T)≤n<m ?
I understand the T(B)≤n but don't know how you know that n<m?
I understand everything up to that point. Thank you very much, I appreciate it.
#### Deveno
##### Well-known member
MHB Math Scholar
Feb 15, 2012
1,967
$n < m$ is given by the problem, yes?
#### baseball3030
##### New member
Sep 18, 2013
9
Yeah but the problem states that the linear map is not onto if m<n so are you assuming that it is onto and then arriving at a contradiction? Thanks,
#### Deveno
##### Well-known member
MHB Math Scholar
Feb 15, 2012
1,967
Yes, I am doing a proof by contradiction (or reductio ad absurdum).
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http://civilservicereview.com/2013/09/pemdas-rules-practice-1-solutions/
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# PEMDAS Rules Practice 1 Solutions
Below are the solutions and answers to the problems in PEMDAS Rules Practice 1. Notice that I have color coded the solution to guide you which operation results to which answer. I have also varied the notations like / and ÷ to familiarize you with both of them. In addition, I have also included operations on fractions with expressions in the numerator and the denominator. In a fraction whose numerator and/or denominator contains one or more operations , you have to simplify first both the numerator and the denominator before dividing. The methods in calculating fractions are shown in numbers 7, 9 and 10.
##### PEMDAS Rules Practice 1 Solutions
1. $2 \times 3 + 4 \times 6$
Solution:
Multiply: 2 x 3 + 4 x 6 = 6 + 24
Add: 6 + 24 = 30
2. $(-3)(2) + 18 \div 3$
Solution:
Multiply: $(-3)(2) + 18 \div 3 = -6 + 18 \div 3$
Divide: $-6 + 18 \div 3 = -6 + 6$
Add: $-6 + 6 = 0$
3. $4 + (6 - 2)^2 + 1$
Solution:
Parenthesis: 4 + (6 – 2)2 + 1 = 4 + 42 + 1
Exponent: 4 + 42 + 1 = 4 + 16 + 1
Add: 4 + 16 + 1 = 21
4. $8(6 - 2) \div 2(5 - 3)$
Solution:
Parenthesis: 8(6 – 2) ÷ 2(5 – 3) = 8(4) ÷ 2(2)
Multiply: 8(4) ÷ 2(2) = 32 ÷ 2(2)*
Divide: 32 ÷ 2(2)= 16(2)
Multiply: 16(2) = 32
*This is the case mentioned in the PEMDAS Rules that when multiplication and division are performed consecutively (without any other operations or grouping symbols in between), the perform the operations from the left hand side to the right hand side.
5. $(-12)(-3) + 8^2$
Solution:
Exponent: (-12)(-3) + 82 = 36 + 64
Multiply: (-12)(-3) + 64= 36 + 64
6. $4 \div 5 \times 25 + 2$
Solution:
Divide: 4/5 x 25 + 2 = 0.8 x 25 + 2*
Multiply: 0.8 x 25 + 2 = 20 + 2
Add: 20 + 2 = 22
*This is the case mentioned in the PEMDAS Rules that when multiplication and division are performed consecutively (without any other operations or grouping symbols in between), the perform the operations from the left hand side to the right hand side.
7. $\displaystyle \frac{-9(2 + 1)}{-2(-2-1)}$
Solution:
Numerator:
Parenthesis: -9(2 + 1) = -9(3)
Multiply: -9(3) = -27
Denominator:
Parenthesis: -2(-2 – 1) = -2(-3)
Multiply: -2(-3) = 6
Divide the numerator by the denominator: -27/6 = -4.5
8. $4( 3 + 1) - 2(5 -2)$
Solution:
Parenthesis: 4(3 + 1) – 2(5 -2) = 4(4) – 2(3)
Multiply: 4(4) – 2(3) = 16 – 6
Subtract: 16 – 6 = 10
9. $\displaystyle \frac{14}{-3-4}$
Solution
Denominator: -3 – 4 = -7
Divide the numerator by the denominator: 14 ÷ -7 = -2
10. $\displaystyle \frac{2^2 - 4^2}{-3 - 1}$
Numerator:
Exponent: 2242 = 416
Subtract: 4 – 16 = -12
Denominator: – 3 – 1 = -4
Divide the numerator by the denominator: -12 ÷ -4 = 3
11. $-(-3) + 8 \div 4$
Solution:
We know that -(-3) = 3, so we only have two operations to perform.
Divide: -(-3) + 8 ÷ 4 = 3 + 2
Add: 3 + 2 = 5
12. $9^2 - 8 - 2^3$
Solution:
Exponent: 92 – 8 – 23 = 81 – 8 – 8
Subtract: 81 – 8 – 8= 73 – 8
Subtract: 73 – 8 = 65
13. $(-7 - 9) (8 - 4) + 4^3 \div 8$
Parenthesis: (-7 – 9) (8 – 4) + 43 ÷ 8 = (-16)(4) + 43 ÷ 8
Exponent: (-16)(4) + 43 ÷ 8 = (-16)(4) + 64 ÷ 8
Multiply: (-16)(4) + 64 ÷ 8 = -64 + 64 ÷ 8
Divide: -64 + 64 ÷ 8 = -64 + 8
Add: -64 + 8 = 56
14. $6 + 3 \times 2 - 12 \div 4$
Multiply: 6 + 3 x 2 – 12/4 = 6 + 6 – 12/4
Divide: 6 + 6 – 12/4 = 6 + 6 – 3
Perform Addition and Subtraction from left to right: 6 + 6 – 3 = 9
15. $7 \times (3 + 2 ) - 5$
Parenthesis: 7 x (3 + 2) – 5 = 7 x 5 – 5
Multiply: 7 x 5 – 5 = 35 – 5
Subtract: 35 – 5 = 30
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https://la.mathworks.com/help/sps/ref/thermocouple.html
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# Thermocouple
Sensor that converts thermal potential difference into electrical potential difference
• Library:
• Simscape / Electrical / Sensors & Transducers
## Description
The Thermocouple block represents a thermocouple using the standard polynomial parameterization defined in the NIST ITS-90 Thermocouple Database [1].
For thermocouples Type B, E, J, K (t<=0 degC), N, R, S or T, the voltage E across the device in mV is
$E\left(mV\right)={c}_{0}+{c}_{1}t+...+{c}_{n}{t}^{n}$
where:
• ci is the ith element of the Coefficients [c0 c1 ... cn] parameter value.
• t is the temperature difference in degrees Celsius between the temperature at the thermal port A and the Reference temperature parameter value.
Note
The equation for voltage across the device as a function of temperature difference is defined in mV. The units of the voltage across the actual device is V.
For thermocouples Type K (t>=0 degC), the equation contains an additional exponential term:
$E\left(mV\right)={c}_{0}+{c}_{1}t+...+{c}_{n}{t}^{n}+{a}_{0}{e}^{{a}_{1}{\left(t-{a}_{2}\right)}^{2}}$
where a0, a1, and a2 are additional coefficients, required only by the Type K thermocouple, defined by the Coefficients [a0 a1 a2] parameter value.
The following equation describes the thermal behavior of the block:
$Q={K}_{d}{t}_{c}\frac{dT}{dt}$
where:
• T is the temperature at port A.
• Q is the net heat flow into port A.
• Kd is the Dissipation factor parameter value.
• tc is the Thermal time constant parameter value.
• dT/dt is the rate of change of the temperature.
To model the thermocouple in free space:
1. Connect the thermocouple to the B port of a Simscape™ Convective Heat Transfer block.
2. Connect the A port of the Convective Heat Transfer block to a Simscape Ideal Temperature Source block whose temperature is set to the ambient temperature.
3. Set the Area parameter of the Convective Heat Transfer block to an approximate area Anom.
4. Set the Heat transfer coefficient parameter of the Convective Heat Transfer block to Kd/Anom.
## Assumptions and Limitations
• The high-order polynomials this block uses are very sensitive to the number of significant figures used for computation. Use all available significant figures when specifying the Coefficients [c0 c1 ... cn] parameter.
• Coefficients [c0 c1 ... cn] are defined for use over a specified temperature range.
• The maximum supported value for n in the Coefficients [c0 c1 ... cn] parameter is 14, that is, the vector cannot have more than 15 elements.
## Ports
### Conserving
expand all
Thermocouple thermal port.
Electrical conserving port associated with the thermocouple positive port.
Electrical conserving port associated with the thermocouple negative port.
## Parameters
expand all
### Electrical
Select one of the modeling options:
• Type B, E, J, K (t<=0 degC), N, R, S or T — This option is equivalent to the block functionality in previous releases.
• Type K (t>=0 degC) — This option adds an exponential term to the block equations when the temperature difference is greater than 0 degrees Celsius.
Vector of coefficients c in the equation that describes voltage as a function of temperature. The maximum length of the vector is 15 elements.
Note
You can download parameters for standard thermocouple types from the NIST database [1]. For information on how to do this, see the Simulink®Approximating Nonlinear Relationships: Type S Thermocouple example.
Vector of additional coefficients a0, a1, and a2, required only by the Type K thermocouple.
#### Dependencies
This parameter is visible only when you select Type K (t>=0 degC) for the Thermocouple model parameter.
### Thermal
Temperature the block subtracts from the temperature at the thermal port in calculating the voltage across the device.
Time it takes the thermocouple temperature to reach 63% of the final temperature change when a step change in ambient temperature occurs.
Thermal power required to raise the thermocouple temperature by one K.
Temperature of the thermocouple at the start of the simulation.
## References
[1] Dean C. Ripple, NIST ITS-90 Thermocouple Database, December 21, 1999 (https://srdata.nist.gov/its90/main/)
## Version History
Introduced in R2008a
|
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|
https://phys.libretexts.org/TextBooks_and_TextMaps/Astronomy_and_Cosmology_TextMaps/Map%3A_Stellar_Atmospheres_(Tatum)/11%3A_Curve_of_Growth/11.5%3A_Curve_of_Growth_for_Lorentzian_Profiles
|
$$\require{cancel}$$
# 11.5: Curve of Growth for Lorentzian Profiles
The optical depth of a line broadened by radiation damping is given, as a function of wavelength, by
$\label{11.5.1}\tau (x)=\tau(0)\frac{l^2}{x^2+l^2},$
where the HWHM is
$\label{11.5.2} l=\frac{\Gamma \lambda_0^2}{4\pi c}$
and the optical thickness at the line center is
$\tau(0) = \frac{e^2\mathcal{N}_1 f_{12}}{m\epsilon_0 c\Gamma}.$
Here $$x = \lambda − \lambda_0$$, and the damping constant $$\Gamma$$ may include a contribution from pressure broadening. As in Section 11.4, in figure XI.4 I draw line profiles for optical thicknesses at the line center $$\tau(0)=\frac{1}{16},\frac{1}{8},\frac{1}{4},\frac{1}{2}, 1 , 2 , 4 , 8$$.
We see that the wings continue to add to the equivalent width as soon as, and indeed before, the central depth has reached unity. On combining equations 11.3.4, \ref{11.5.1},2 and 3, we obtain the following expression for the equivalent width:
$\label{11.5.4}W=\frac{\Gamma \lambda_0^2}{2\pi c}\int_0^\infty \left ( 1-\text{exp}\left \{-\frac{\tau(0)}{y^2+1}\right \}\right )\,dy,$
in which $$y = x/l$$ - i.e. distance from the line center in units of the HWHM.
If we now substitute $$y = \tan \theta$$, the expression for the equivalent width becomes
$\label{11.5.5}W=\frac{\Gamma \lambda_0^2}{2\pi c} \int_0^{\pi/2} \frac{1-\text{exp}\left [-\tau(0)\cos^2 \theta \right ]}{\cos^2 \theta }\,d\theta .$
Now that we have a finite upper limit, the expression can be integrated numerically without artificial and unjustified truncation. As described in the Appendix to Chapter 10, calculation of the trigonometric function cos can be avoided, and hence the integration much speeded up, by the substitution of $$t=\tan (\frac{1}{2}\theta)$$. Although the denominator of the integrand is obviously zero at the upper limit, so is the numerator, and the value of the integrand at the upper limit is finite and equal to $$\tau (0)$$. Figure XI.5 shows the equivalent width, in units of $$\frac{\Gamma \lambda_0^2}{2\pi c}$$ as a function of $$\tau(0)$$.
$$\text{FIGURE XI.4}$$ $$\text{FIGURE XI.5}$$
|
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|
https://forum.effectivealtruism.org/posts/A7NWTjnWZPmjyLdtT/donations-list-website-tutorial-and-request-for-feedback
|
# 18
EA Funding
Frontpage
## Introduction
Donations List Website (DLW) is a website that tracks the public or explicitly shared donations of individuals (mostly in the effective altruism and rationality communities), private foundations, and other entities. The website was created and is maintained by Vipul Naik, with contributions from me (Issa Rice).
The aim of this post is to introduce DLW to the world and gather some feedback. DLW has been in active development since January 2017, and is planned for launch by the end of December 2019. At the moment DLW is in a pre-release state, where Vipul and I are adding both data and features to the site.
The first half of this post gives a tutorial of DLW, focusing especially on the features of the site that are not obvious to casual inspection. The second half of this post is a request for feedback; Vipul and I are interested in using the feedback to help us decide where to focus our efforts for future development.
## Tutorial
This section is a tutorial of the main features of Donations List Website (DLW), with a focus on the parts that are probably non-obvious to casual users.
### Main page
The main page of DLW shows information aggregated from all donations tracked by the site. The main page has the path starting with / or /index.php.
The main page of DLW has an optional parameter called display that changes the kind and number of donations listed. Currently, the possible values are:
• individual-scale, which displays donations made by individuals (in other words, excluding donations made by private foundations and other group entities)
• full, which displays all donations tracked by DLW
• empty value (the default), which restricts donations to the top 30 donors, donees, and cause areas
### Donor page
Each donor tracked by DLW has a donor page. Donor pages have a path starting with /donor.php. An example is the donor page for the Open Philanthropy Project.
For the Open Philanthropy Project in particular, there is a table of disclosures (from before it stopped announcing disclosures). Currently no other donor has disclosures data.
### Donee page
Each donee tracked by DLW has a donee page. Donee pages have a path starting with /donee.php. An example is the donee page for LessWrong 2.0.
Some entities are both a donor and a donee, in which case there will be separate pages for each role. An example is the Berkeley Existential Risk Initiative (BERI):
### Donor–donee page
It is sometimes interesting to look at a specific donor–donee pair and see all the donations made by the donor to the donee, their relationship, a list of documents that mention both of them, and so on. For this, DLW has a donor–donee page for each such pair. Donor–donee pages have a path starting with /donorDonee.php. An example of this is the page for Open Philanthropy Project donations made to the Machine Intelligence Research Institute.
### Influencer page
The influencer page looks at the amount of money influenced (a.k.a. the “money moved”) by an entity. This is tracked separately from donations, so it is possible to compare the amount of money moved that is claimed (gathered from the entity claiming money moved, e.g. GiveWell) with the amount of money moved that is actually accounted for (gathered from the entities making or receiving the donations, e.g. Against Malaria Foundation or individual donors). Influencer pages have a path starting with /influencer.php.
The only entity for which we currently track money moved information is GiveWell. You can see the amount of influence claimed vs amount of money accounted for in the money moved table.
Even for non-GiveWell entities, influencer pages exist. An example is Chloe Cockburn. In these cases, there is no comparison between the “money moved claimed” and “money moved accounted for”, because we have not entered any data for the “money moved claimed”. However, it is still possible to see a list of all donations that were influenced.
### Cause area filter
Most pages on DLW accept an optional cause area parameter called cause_area_filter. Using this parameter filters the donations to show only those with a matching cause area.
To give some examples:
Donee pages don’t have this option, because most donees only work within a single cause area.
The about page discusses how DLW is built and reliability concerns for the data.
## Request for feedback
This section is an official request for feedback from readers of this forum. Vipul and I want to make Donations List Website (DLW) as useful as possible to people who think about effective giving, flow of money in the non-profit world, real-world decision making, and similar topics. To help us decide what improvements to prioritize, we would like to hear from you what excites you most about DLW, what you could see yourself using it for, what improvements would make you use it more, and so on.
Below, we provide some structure for feedback. We would appreciate feedback as (1) comments on this post, or (2) submissions to this Google Form. The differences between the two are that the Google Form has fields for each question (more structure), can be submitted anonymously, and individual responses will not be shared publicly.
### Did you already know about DLW? Do you use it for anything?
To start off, we are curious to get a feel for whether people have already discovered DLW on their own and whether they use it for anything.
As an example response, I will talk a little about my own experience using DLW. I’ve found it useful for the following:
• Since October 2017, I have been working on a website called AI Watch that tracks activity in the world of AI safety. More recently, I’ve expanded the scope of AI Watch to cause areas outside AI safety, resulting in Org Watch. Having access to data from DLW has helped me find names of people involved in various cause areas, which has made data collection faster for my work on these other websites.
• I had been curious about the donations of certain individuals (examples: Vitalik Buterin and gwern) but as far as I could tell, there was no canonical location listing donations made by them. DLW has solved this problem for me for these individuals.
• One day, I suddenly became curious about the indirect flow of money from the Open Philanthropy Project (Open Phil) to the Machine Intelligence Research Institute (MIRI). By “indirect flow of money” I mean not grants that Open Phil has made to MIRI, but where Open Phil grants money to some intermediate entity, who then donates to MIRI. Having access to both the DLW and Org Watch datasets meant I could do some exploration by looking at (1) organizations that had received money from Open Phil, that had also donated to MIRI, and (2) individuals who worked for organizations that received funding from Open Phil, who were also individual MIRI donors.
### Potential improvements – what are your thoughts?
This subsection lists some potential improvements we’ve thought of.
#### Add more foundation giving data
Currently, DLW tracks the giving data of foundations including the Gates Foundation, Arnold Foundation, Hewlett Foundation, Good Ventures/Open Philanthropy Project, and Ford Foundation. However, there are many more foundations whose donations we could track.
#### Add more individual giving data
Similar to the above, there are many individuals whose donations we could track.
DLW already has an emphasis on these communities, but there’s still more that can be added.
#### Add more money moved data
Currently we have only entered claimed money moved data for GiveWell. However there are some other entities that publish money moved data, like Animal Charity Evaluators.
#### Systematically track considerations that donors make
Donors concerned with effective giving have many considerations as they think through their decision. These include:
• Giving now vs later
• Donor coordination and giver’s dilemma
• Donating to a single charity vs multiple charities
• How much weight to place on cost-effectiveness calculations vs less quantitative forms of modeling and reasoning
• Whether to use a donor-advised fund
• Size of average donation (relative to total wealth)
• Which population ethics to use
• Which worldviews to use, and what entities to see as “equal” (all animals? all humans? all people with a certain IQ or ability?)
Currently, the reasoning above is scattered across many different blog posts, comments, articles, and so forth. It is difficult to answer questions like “Where and how do people who give consideration to the giver’s dilemma donate?” and “Where do people who share my population ethics and worldview donate?”
It seems plausible that DLW could make progress on aggregating some of this discussion and linking it with the existing donations data.
#### Classify cause areas better
Although donations on DLW are usually tagged with a cause area, so far this has been done in a somewhat ad hoc manner, so there are some problems like the same cause area being phrased in different ways and the cause area hierarchy being a mess.
I did some work on this previously in a cause prioritization context (see entries for cause area classification and list of classifications of philanthropy on the Cause Prioritization Wiki), but this sort of work is also valuable for better classifying donations.
#### Include giving data (of existing donors/donees) in a more timely manner
Even after we add donations data for a donor or donee, new donations are made over time, so there is a question of how often DLW should update the data for existing donors and donees. Currently the updating schedule is somewhat arbitrary.
We have written up a series of steps for updating existing data for donors and donees, so updating donations data for most entities is pretty straightforward.
#### Include giving data (of existing donors/donees) more completely
Occasionally a subset of donations made by an entity is easy to access and process by a machine, while the rest are not. An example of this is the Gates Foundation, where donations tracked through the International Aid Transparency Initiative are easy to process, but where the rest of the donations are difficult to process at the grant level.
There has been a lot of discussion over the years about effective giving, personal donations, organization updates, and other documents that would belong on DLW. We have added only a fraction of the possible documents, so adding more is another option.
Generally we try to add graphs for each table displayed, but there are some exceptions like the donee page.
#### Summarize existing data more
It might be the case that the data of interest is already part of DLW, but isn’t presented in the most useful way. Examples of this are donor intersection pages and donee intersection pages, where one wants to compare two specific donors or two specific donees.
### Other features?
We are interested in hearing ideas other than the ones we listed.
## Acknowledgments
Thanks to Vipul Naik for feedback on this post and for funding my work on it.
New Comment
Cool project! I'm impressed by the thoroughness of the lists.
This will take a lot of ongoing attention to keep up-to-date. Are you planning to do list maintenance as ongoing volunteer work? Are you intending to seek funding for ongoing maintenance?
Also, who do you have in mind as your intended customer?
So far almost all DLW work by me has been contract work paid by Vipul, and my guess is it will stay like this for the foreseeable future. We have not sought other sources of funding, but are interested in receiving funding (for my ongoing work).
As mentioned in the post, the intended audience is something like "people who think about effective giving, flow of money in the non-profit world, real-world decision making, and similar topics". To give some examples:
• Ryan Carey has a GitHub repository with data analysis of Open Phil's grants data. (Last updated 2018-02-11.)
• Here is another example, but part of a closed Facebook group so I won't describe it. (Probably last updated around 2018-01-14.)
• Michael Dickens wrote a post entitled "Where Some People Donated in 2017" recording where some EA and EA-peripheral people donated. (Last updated 2018-02-14.)
• In June 2017, there was a Facebook event called "What's Up With the Open Philanthropy Project?" The event looked at some of Open Phil's work, compiling some documents about some of Open Phil's grants in the process. Looking at the timestamps, I think the Google Docs were created when the meetup began, and were filled in during the course of the meetup. (Last updated 2017-06-09.)
I think in all the above cases, either the current version of DLW or an improved version in the future performs a superset of the data collection/analysis, is continually updated, and provides a single location for all the data and analysis.
Vipul has also made comments (1, 2) and at least one post using in part data collected by DLW, to make observations or answer people's questions.
I've found the service to be pretty valuable so far, though mainly for keeping track of OpenPhil. I have funded \$645 of work on this (via Vipul to Issa) so far.
This seems like a huge amount of work for what seems like a somewhat uncertain impact.
|
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|
https://codegolf.meta.stackexchange.com/questions/13510/what-to-do-about-a-user-excessively-posting-useless-comments
|
What to do about a user excessively posting useless comments?
A user (who's not particularly new, yet I'd never noticed him until about a week ago) has been posting excessive comments. I don't mean excessive comments like mine here, I mean excessive comments along the lines of...
• Whoa, how is this even possible?
• Is this ever going to end?????
• You got my name right!!!1!!1!11! :D (x5)
These comments in small numbers don't seem to be a problem. But when a user begins commenting on more or less every post in a thread, it gets a little obnoxious. When a user has something to say - not constructive, not destructive, just noise - about 50% of the answers he sees, I don't think anyone appreciates it.
I've asked this user to stop, and I was ignored. I won't link to his profile for obvious reasons. He has posted 80 comments in the last two days, ten of which I noticed without seeking them out.
This behavior clearly doesn't warrant a ban/suspension/privilege-revoke, so what can be done?
• Telling someone that their exceptional answer is wonderfully written, or has never been done before, or is the greatest thing they've ever seen on the site, is something to be encouraged. - no, it's not. Jul 30 '17 at 21:36
• @Mithrandir Oh, thanks. Jul 30 '17 at 21:47
Flag the comments as "no longer needed" as you see them. If they're really getting out of hand, flag them for moderator attention with details about how this is becoming a frequent problem with the users. The moderators will take action as they see necessary.
For what it's worth, spamming useless comments is grounds for a suspension in my opinion.
• Flags, certainly. Too bad not constructive isn't an option anymore. These comments were never needed in the first place, and no longer needed doesn't cast mod flags warning about X flags in Y days. Jul 30 '17 at 23:56
• @Dennis Why is not constructive no longer an option? Is this only our site or all sites?
– Grain Ghost Mod
Jul 31 '17 at 1:48
• Jul 31 '17 at 2:03
• @Dennis The middle flag - "no longer needed" - is new, and is intended to cover all of "too chatty", "obsolete", and the non-abusive uses of "not constructive". Jul 31 '17 at 13:30
• @TheLethalCoder It doesn't cover them though. Aug 3 '17 at 12:32
• Hmm, I've now got about 35 helpful flags that got comments deleted. How long will it be until the system does something about his commenting privilege? Aug 3 '17 at 23:01
• @MDXF I don't know if the system will do anything automatically, but the moderators will if they deem it necessary.
– user45941
Aug 4 '17 at 4:20
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|
https://www.omnicalculator.com/other/note-frequency
|
Note name
A
Octave
4 (1-line)
Frequency
440
Hz
# Note Frequency Calculator
By Rita Rain
Last updated: Sep 07, 2020
Table of contents:
This note frequency calculator is a convenient tool to determine the frequency of musical notes tuned in the twelve-tone equal temperament. In the text, you'll find the note frequency chart and a guide on how to use the note frequency converter.
We'll also cover the basics of the physics of sound - if you want to learn more about it, check out our relevant calculators:
## The frequency of musical notes
Sound is a wave which travels through a medium, such as air or water. All sounds consist of sine waves with different frequencies and amplitudes. Amplitude determines volume, and frequency determines pitch.
Technically, frequency is the number of completed wave cycles per second, and is expressed in Hertz. For example the frequency of the musical note C4 is approximately 262 Hz. This means the sound wave has 262 cycles per second.
Musical notes have determined frequencies. For example, in the twelve-tone equal temperament (the most common tuning system since the 18th century), note A4 has a frequency of 420 Hz.
If one note is double the frequency of another, they sound similar, so we designate them with the same letter. We then add a number to represent the octave - that is to say whether we mean a higher or lower D.
This way of representing musical notes if called the scientific pitch notation.
## How to use the note frequency calculator
1. Choose the name of the note. Note pairs like F♯ and G♭, or C♯ and D♭, are enharmonic equivalents, which means they denote the same sound.
2. Choose an octave.
3. By default, the calculator rounds the frequency of the musical note to one decimal place. You can change it in the `advanced mode` (below the note frequency calculator).
## The note frequency chart
Below you can see a table with the rounded frequencies of musical notes in Hertz:
Octave / Note
0
1
2
3
4
5
6
7
8
C
16
33
65
131
262
523
1047
2093
4186
C♯
17
35
69
139
277
554
1109
2217
4435
D
18
37
73
147
294
587
1175
2349
4699
D♯
19
39
78
156
311
622
1245
2489
4978
E
21
41
82
165
330
659
1319
2637
5274
F
22
44
87
175
349
698
1397
2794
5588
F♯
23
46
93
185
370
740
1480
2960
5920
G
25
49
98
196
392
784
1568
3136
6272
G♯
26
52
104
208
415
831
1661
3322
6645
A
28
55
110
220
440
880
1760
3520
7040
A♯
29
58
117
233
466
932
1865
3729
7459
B
31
62
123
247
494
988
1976
3951
7902
Rita Rain
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https://pos.sissa.it/379/009/
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Volume 379 - The 18th International Workshop on Polarized Sources, Targets, and Polarimetry (PSTP2019) - Polarimetry
Polarized Electron and Hadron Beams at eRHIC
C. Montag
Full text: pdf
Published on: September 23, 2020
Abstract
The electron ion collider (EIC) eRHIC at BNL aims at a luminosity of $10^{34}\,{\rm cm}^{-2}{\rm sec}^{-1}$ in collisions of polarized electron and polarized proton, deuteron, and $^3{\rm He}$ beams. We will present an overview of the proposed facility with an emphasis on generation and acceleration of the polarized beams and the expected polarization performance.
DOI: https://doi.org/10.22323/1.379.0009
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.
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https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=146&t=62067&p=237997
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## Negative overall order
Rida Ismail 2E
Posts: 139
Joined: Sat Sep 07, 2019 12:16 am
### Negative overall order
Does anyone understand how an overall order can be negative and if so can you please explain it to me?
Sarah Zhari 1D
Posts: 103
Joined: Sat Sep 14, 2019 12:16 am
### Re: Negative overall order
I think that an order can be negative if as you increase the concentration of a particular reactant, the overall rate of reaction decreases.
Anisha Chandra 1K
Posts: 118
Joined: Thu Jul 11, 2019 12:17 am
### Re: Negative overall order
Can the whole reaction have a negative overall order or only certain steps?
William Chan 1D
Posts: 102
Joined: Sat Sep 14, 2019 12:15 am
### Re: Negative overall order
I think it is rare, but if you increase the concentration of certain reactants, then the overall reaction rate will decrease.
I found an example of the conversion of ozone to oxygen here: https://www.quora.com/What-are-negative-order-reactions-And-what-are-the-examples
KBELTRAMI_1E
Posts: 108
Joined: Sat Jul 20, 2019 12:17 am
### Re: Negative overall order
Like first vs second order? Negative as in less than a zero order? What would that be called and can you give an example if you found a problem with it?
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http://www.mathcaptain.com/geometry/vertical-angles.html
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Vertical angles can be defined as the pairs of non-adjacent angles in opposite positions formed by the intersection of two straight lines are known as vertical angles.
In the figure, $\angle$1 and $\angle$3 are a pair of vertical angles. Another pair of vertical angles is $\angle$2 and $\angle$4.
## Vertical Angles Theorem
If two angles are vertical angles, then they have equal measures.
Construction: Let $\overleftrightarrow{AB}$ and $\overleftrightarrow{CD}$ be two intersecting lines in a plane, intersecting at the point P, as shown in the figure. Here, the angles $\angle$APD and $\angle$BPC are vertical angles.
To Prove:
$$\angle APD \cong \angle BPC$$
Proof:
S. No.StatementReason
1∠APD+∠APC = 180oAngles on a straight line (Supplementary angles)
2∠BPC+∠APC = 180oAngles on a straight line
3∠APD+∠APC=∠BPC+∠APCFrom (1) & (2)
4∠APC≅∠BPC(3), Subtracted ∠APC from both sides
Hence, we proved the theorem.
### Complementary Angles
A Vertical Line Icosahedron Vertices What are Angles Find the Area of a Parallelogram with Vertices Pentagonal Prism Vertices Rational Function Vertical Asymptote Rectangular Prism Vertices Triangular Pyramid Vertices Vertical Distance Formula Angle Relationship Angle of Depression and Angle of Elevation A Acute Angle
Find Vertical Asymptote Calculator Angle Solver Coterminal Angles Calculator
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https://dsp.stackexchange.com/tags/corners/hot?filter=all
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# Tag Info
4
Short answer is no, there are none, or maybe none that made it until becoming a de facto standard like FAST or SIFT. This is still an open area of research by the way if you plan to work in this field. Mostly, the issues are linked to the fragility of color representation in digital images. The common RGB color space is not really relevant (distances ...
3
The point descriptor usually requires samples at some specific locations from around the detected point. If you have point location refined and orientation assigned, you just shift and rotate the locations before computing point descriptor. Some simple descriptors require samples at discrete locations (e.g. 15x15 pixel image patch) and applying shift+...
2
can't we use other function such as: $R=1-(\lambda_1+\lambda_2)^2$ This formula isn't as useful, because it doesn't differentiate between two equally large eigenvalues (a corner) and one twice as large eigenvalue plus one very small one (a straight line). So for example $\lambda_1 = 2, \lambda_2 = 0$ will give the same result as $\lambda_1 = 1, \lambda_2 = ... 2 The solution is to use an "homography" / aka "projective transformation" (see this PDF, page 16). Here is a working code showing how to do it with Python + OpenCV. 1 I'll simply present a series of results relevant to this question. Note that eigenvalues of this matrix are non-negative Let$x = [u\ v]^T$$$x^TMx = [u\ v] \begin{bmatrix} I_x^2 & I_x I_y \\ I_x I_y & I_y^2 \end{bmatrix} \begin{bmatrix} u \\ v \end{bmatrix} = u^2 I_x^2 + 2uv I_x I_y + v^2 I_y^2 = (uI_x + vI_y)^2 \geq 0$$ Hence$M$is positive-... 1 Threshold the image to convert into binary image. Check whether it is a corner or not by dilating with these kernels separately on corners detected by corner detection.$$E_1 = \begin{bmatrix}0 & 0 &0 & 1& 0\\0 & 0 & 0 & 1& 0\\0 & 0 & 0 & 1& 0\\1 & 1 & 1 & 1& 0\\0 & 0 & 0 & 0& 0\... 1$M$is the structure tensor. The points where the signal changes in two directions are the points for which both eigenvalues of$M$are large.$R = det(M) - k*trace^2(M) = \lambda_1\lambda_2 - k(\lambda_1 + \lambda_2)^2$, so$R$is large when both$\lambda_1$and$\lambda_2$are large. 1 I think the first smoothing, by$\sigma_D$, is only done to get more stable derivatives whereas in the second step the convolution by a Gaussian with$\sigma_I$is done to establish the 'scale-space' in which the operator is applied. Ignoring$\sigma_D\$, this looks like this in Matlab: dx = [-1 0 1; -1 0 1; -1 0 1]; % Simple mask for derivative Ix = ...
Only top voted, non community-wiki answers of a minimum length are eligible
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https://www.gradesaver.com/textbooks/math/algebra/algebra-a-combined-approach-4th-edition/chapter-6-section-6-6-solving-quadratic-equations-by-factoring-exercise-set-page-459/77
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## Algebra: A Combined Approach (4th Edition)
$(x-6)(x+1)=0$
The answer is $(x-6)(x+1)=0$ since the values $x=6$ and $x=-1$ are the only ones that satisfy the equation, i.e., these values are the only solutions
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http://theinfolist.com/php/SummaryGet.php?FindGo=Albedo
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TheInfoList
The percentage of diffusely reflected sunlight relative to various surface conditions
Albedo (/ælˈbd/) (Latin: albedo, meaning 'whiteness') is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that reflects all incident radiation.
Surface albedo is defined as the ratio of radiosity to the irradiance (flux per unit area) received by a surface.[1] The proportion reflected is not only determined by properties of the surface itself, but also by the spectral and angular distribution of solar radiation reaching the Earth's surface.[2] These factors vary with atmospheric composition, geographic location and time (see position of the Sun). While bi-hemispherical reflectance is calculated for a single angle of incidence (i.e., for a given position of the Sun), albedo is the directional integration of reflectance over all solar angles in a given period. The temporal resolution may range from seconds (as obtained from flux measurements) to daily, monthly, or annual averages.
Unless given for a specific wavelength (spectral albedo), albedo refers to the entire spectrum of solar radiation.[3] Due to measurement constraints, it is often given for the spectrum in which most solar energy reaches the surface (between 0.3 and 3 μm). This spectrum includes visible light (0.4–0.7 μm), which explains why surfaces with a low albedo appear dark (e.g., trees absorb most radiation), whereas surfaces with a high albedo appear bright (e.g., snow reflects most radiation).
Albedo is an important concept in climatology, astronomy, and environmental management (e.g., as part of the Leadership in Energy and Environmental Design (LEED) program for sustainable rating of buildings). The average albedo of the Earth from the upper atmosphere, its planetary albedo, is 30–35% because of cloud cover, but widely varies locally across the surface because of different geological and environmental features.[4]
The term albedo was introduced into optics by Johann Heinrich Lambert in his 1760 work Photometria.
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https://www.physicsforums.com/threads/can-you-help-me-please.232258/
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# Can you help me , please?
1. Apr 30, 2008
### vip89
Can you help me , please??
Can you solve this problem by using Calculus l "" Volumes by Slicing and Rotation About an Axis"" ??
Develop a formula for the volume of an ellipsoid of the form
( x^2/a^2)+(y^2/b^2)+(z^2/c^2)=1, a, b, c > 0.
I want the steps , because I know the final answer .
2. Apr 30, 2008
### tiny-tim
Welcome to PF!
Hi vip89! Welcome to PF!
Show us what you've tried, and where you're stuck, and then we'll know how to help you!
3. Apr 30, 2008
### vip89
I know that I must sketch,find the equation of the cross section , find the area from A=piab and x^2/a^2+y^2/b^2=1
Finally,I must find the definit integral of the area
the final answer will be 4pi/3 abc
4. Apr 30, 2008
### vip89
I dont know how to do this , and how to apply my steps?!
5. Apr 30, 2008
### tiny-tim
Hi vip89!
ok … we usually take horizontal cross-sections (don't have to) …
in other words, the intersection with a plane z = constant.
So what is the equation (in x and y) if you put z = w (a constant) … ?
… and then what is the area?
6. May 2, 2008
### vip89
thnkx very much
7. May 6, 2008
### vip89
I trid to solve it by this way,but strang things will appear,the equation be more complicated!!
8. May 6, 2008
### Tedjn
Show us your work. You can either take a picture, scan it, and upload it, or you can try using LaTeX in between [noparse]$$and$$[/noparse] tags.
9. May 7, 2008
### tiny-tim
Hi vip89!
Show us how far you got …
What equation (in x and y) did you get for the horizontal cross-sections when you put z = w (a constant)?
10. May 7, 2008
### rocomath
lol ... funny kid we're not here to do your hw
11. May 7, 2008
### tiny-tim
oi … rocomath! … that was vip89's very first post (seven days ago)!
… but he's getting the hang of it now!
If you can't help, just say "welcome!"
12. May 7, 2008
### rocomath
sorry :( i've grown less tolerant towards ppl just wanting us to do their hw.
13. May 9, 2008
### vip89
These are my trials
I have the idea but cant get the right answer
THNKX
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14. May 9, 2008
### vip89
Continue:
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15. May 10, 2008
### HallsofIvy
Staff Emeritus
In your first sheet, you start with $$\int A(x)dx$$ and then immediately switch to $$\int x y[/itex] without a "dx" at all. How did that happen? I also cannot see any good reason for writing x as a function of y and z and writing y as a function of x and z. You are correct that [tex]y= b\sqrt{1- x^/a^2- z^2/c^2}$$ and that $$z= c\sqrt{1- x^2/a^2- y^2/b^2$$. The first tells you that when z= 0, $$y= b\sqrt{1- x^2/a^2}$$ and the second tells you that when y= 0, $$z= c\sqrt{1- x^2/a^2}$$. In other words, at each x, the cross section is an ellipse with semi-axes $$b\sqrt{1-x^2/a^2}$$ and $$c\sqrt{1- x^2/a^2}$$. Do you know that the area of an ellipse with semi-axes a and b is $$\pi ab$$?
16. May 11, 2008
### tiny-tim
hmm … let's start at the top of your page 3 …
which I take it is following my suggestion …
And then you try to use the formula A = πab for the area of an ellipse.
BUT … that formula only applies if the equation for the ellipse is in the standard form, with nothing but x² and y² on the left and "= 1" on the right.
You must put w² = (1 - x²/a² - y²/b²)c² into that form first.
Then you will get a "new a and b" that are not the same as the original a and b.
ok … rearrange w² = (1 - x²/a² - y²/b²)c² into the standard form … and then find the area.
Similar Discussions: Can you help me , please?
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https://opacus.ai/api/grad_sample_module.html
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Extends nn.Module so that its parameter tensors have an extra field called .grad_sample.
Parameters
• m (Module) – nn.Module to be wrapped
• batch_first – Flag to indicate if the input tensor to the corresponding module has the first dimension representing the batch. If set to True, dimensions on input tensor are expected be [batch_size, ...], otherwise [K, batch_size, ...]
• loss_reduction – Indicates if the loss reduction (for aggregating the gradients) is a sum or a mean operation. Can take values “sum” or “mean”
• strict (bool) – If set to True, the input module will be validater to check that GradSampleModule has grad sampler functions for all submodules of the input module (i.e. if it knows how to calculate per sample gradients) for all model parameters. If set to False, per sample gradients will be computed on “best effort” basis - they will be available where possible and set to None otherwise. This is not recommended, because some unsupported modules (e.g. BatchNorm) affect other parameters and invalidate the concept of per sample gradients for the entire model.
Raises
NotImplementedError – If strict is set to True and module m (or any of its submodules) doesn’t have a registered grad sampler function.
Adds hooks to model to save activations and backprop values. The hooks will 1. save activations into param.activations during forward pass 2. compute per-sample gradients in params.grad_sample during backward pass. Call remove_hooks(model) to disable this.
Parameters
• model – the model to which hooks are added
• batch_first (bool) – Flag to indicate if the input tensor to the corresponding module has the first dimension representing the batch. If set to True, dimensions on input tensor are expected be [batch_size, ...], otherwise [K, batch_size, ...]
• loss_reduction (str) – Indicates if the loss reduction (for aggregating the gradients) is a sum or a mean operation. Can take values “sum” or “mean”
Return type
None
capture_backprops_hook(module, _forward_input, forward_output, loss_reduction, batch_first)[source]
Computes per sample gradients given the current backprops and activations stored by the associated forward hook. Computed per sample gradients are stored in grad_sample field in each parameter.
For non-recurrent layers the process is straightforward: for each loss.backward() call this hook will be called exactly one. For recurrent layers, however, this is more complicated and the hook will be called multiple times, while still processing the same batch of data.
For this reason we first accumulate the gradients from the same batch in p._current_grad_sample and then, when we detect the end of a full backward pass - we store accumulated result on p.grad_sample.
From there, p.grad_sample could be either a Tensor or a list of Tensors, if accumulated over multiple batches
Parameters
Deleted .grad_sample attribute from all model parameters
disable_hooks()[source]
Globally disable all hooks installed by this library. Why is this needed? As per https://github.com/pytorch/pytorch/issues/25723, there is a bug in Autograd that makes removing hooks do nothing if the graph was already constructed. For this reason, we have this method to at least turn them off.
Return type
None
enable_hooks()[source]
The opposite of disable_hooks(). Hooks are always enabled unless you explicitly disable them so you don’t need to call this unless you want to re-enable them.
Return type
None
forward(*args, **kwargs)[source]
Defines the computation performed at every call.
Should be overridden by all subclasses.
Note
Although the recipe for forward pass needs to be defined within this function, one should call the Module instance afterwards instead of this since the former takes care of running the registered hooks while the latter silently ignores them.
classmethod is_supported(module)[source]
Checks if this individual model is supported (i.e. has a registered grad sampler function)
Notes
Note that this method does not check submodules
Parameters
module (Module) – nn.Module to be checked
Return type
bool
Returns
True if grad sampler is found, False otherwise
Rearrange activations and grad_samples based on loss reduction and batch dim
Parameters
• module (Module) – the module for which per-sample gradients are computed
• backprops (Tensor) – the captured backprops
• loss_reduction (str) – either “mean” or “sum” depending on whether backpropped loss was averaged or summed over batch
• batch_first (bool) – True is batch dimension is first
Return type
remove_hooks()[source]
Removes hooks added by add_hooks()
Return type
None
Sets .grad_sample to None
to_standard_module()[source]
Returns the standard nn.Module wrapped by this, eliminating all traces of grad samples and hooks
Return type
Module
Returns
The wrapped module
classmethod validate(module, *, strict=False)[source]
Check if per sample gradients can be fully computed for a given model
Parameters
• module (Module) – nn.Module to be checked
• raise_if_error – Behaviour in case of a negative check result. Will
• False (return the list of exceptions if set to) –
• otherwise (and throw) –
Return type
Returns
Empty list of validation is successful. List of validation errors if raise_if_error=False and unsupported modules are found
Raises
NotImplementedError – If raise_if_error=True and unsupported modules are found
Clears p.grad and p.grad_sample for all of it’s parameters
Notes
set_to_none argument only affects p.grad. p.grad_sample is never zeroed out and always set to None. Normal grads can do this, because their shape is always the same. Grad samples do not behave like this, as we accumulate gradients from different batches in a list
Parameters
• set_to_none (bool) – instead of setting to zero, set the grads to None. (only
• None) (affects regular gradients. Per sample gradients are always set to) –
Creates a _current_grad_sample attribute in the given parameter, or adds to it if the _current_grad_sample attribute already exists.
• param (Tensor) – Parameter to which grad_sample will be added
• grad_sample (Tensor) – Per-sample gradients tensor. Must be of the same shape as param with extra batch dimension
• layer (Module) – nn.Module parameter belongs to
None
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http://www.go4expert.com/forums/help-cmd-school-network-hacking-t28913/
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# Help with cmd school network hacking
Light Poster
Hello,
I have a problem; i can't get in schools cmd, i've tried several options (notepad and save it as a .bat file; nothing works) does somebody know how i can get on cmd ?
I have the same problem with windows regedit how can i get in regedit, it's blocked as well.
Thanks
0
Go4Expert Member
copy the below command and paste it to a notepad. change the extension as .inf... Then execute it.
[DefaultInstall]
|
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https://en.wikipedia.org/wiki/Volume%E2%80%93price_trend
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Volume–price trend
Volume–price trend (VPT) (sometimes price–volume trend) is a technical analysis indicator intended to relate price and volume in the stock market. VPT is based on a running cumulative volume that adds or subtracts a multiple of the percentage change in share price trend and current volume, depending upon the investment's upward or downward movements.[1]
Formula
${\displaystyle {\text{VPT}}={\text{VPT}}_{\text{prev}}+{\text{volume}}\times {{\text{close}}_{\text{today}}-{\text{close}}_{\text{prev}} \over {\text{close}}_{\text{prev}}}}$
VPT total, i.e. the zero point, is arbitrary. Only the shape of the resulting indicator is used, not the actual level of the total.
VPT is similar to on-balance volume (OBV),[2] but where OBV takes volume just according to whether the close was higher or lower, VPT includes how much higher or lower it was.
VPT is interpreted in similar ways to OBV. Generally, the idea is that volume is higher on days with a price move in the dominant direction, for example in a strong uptrend more volume on up days than down days. So, when prices are going up, VPT should be going up too, and when prices make a new rally high, VPT should too. If VPT fails to go past its previous rally high then this is a negative divergence, suggesting a weak move.
Similar indicators
Other price × volume indicators:
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https://codegolf.stackexchange.com/questions/76704/write-a-palindrome-that-prints-hello-world-without-using-comments
|
Simple, right?
Nope.
# You have one restriction: you may not use comments.
• Normal // or # comments
• Adding extraneous characters to a string literal
• Creating a string literal to hide characters
You may not use a pre-defined procedure to print "Hello, World!". (like HQ9+'s H command)
This is , so the shortest answer in bytes wins.
## marked as duplicate by AdmBorkBork, Blue, FryAmTheEggman, jimmy23013, Mego♦Mar 31 '16 at 13:52
• Almost duplicate. I'll leave it up to the community to decide whether the comment restriction makes a sufficient difference or not. (Although I personally don't think comment restrictions work... once you get to 2D languages, you can easily include all sorts of code that isn't a no-op, but never happens to be executed.) – Martin Ender Mar 31 '16 at 13:25
• I'm voting to close as a duplicate, since there are many answers from the other challenge that can be used without modification here. – AdmBorkBork Mar 31 '16 at 13:36
• @CrazyPython Updating rules after an answer has been posted is highly frowned upon, on top of this already being a duplicate. For future challenges, I highly recommend using The Sandbox so you can get meaningful feedback on challenges before they're posted. – AdmBorkBork Mar 31 '16 at 13:50
• @CrazyPython The fact that "joke" answers were allowed under the rules-as-originally-written highlights the fact that this challenge wasn't ready for posting to main. The fact that you're adding "no comments" to the restrictions doesn't change the fact that many answers from the linked challenge can be posted here without modification, making this one a duplicate. – AdmBorkBork Mar 31 '16 at 13:59
• @CrazyPython No, sorry for being unclear. I meant that adding "no comments" as a restriction to "palindrome Hello World" doesn't make it a sufficiently different enough challenge to not be a duplicate. If you want to discuss this further, let's take it to chat. – AdmBorkBork Mar 31 '16 at 14:08
## Stuck, 0 bytes
I think this wins? An empty program in stuck prints Hello, World!
• And we have a winner.. +1 – Zach Gates Mar 31 '16 at 13:30
• I just posted this to show how bad/repeated this challenge was, I don't expect anything from it – Blue Mar 31 '16 at 13:31
• Standard loophole guidelines? – noɥʇʎԀʎzɐɹƆ Mar 31 '16 at 13:46
• Look at the new rules. – noɥʇʎԀʎzɐɹƆ Mar 31 '16 at 13:47
# Bash, 47 bytes
echo Hello, World!
exit
tixe
!dlroW, olleH ohce
# Gogh, 31 bytes
"Hello, World!"Ƥ"!dlroW ,olleH"
### Explanation
"Hello, World!" “ Push the string literal ”
¡ “ Output the TOS ”
"!dlroW ,olleH" “ Push the string literal ”
“ Non-implicit output ”
## Help, WarDoq!, 1 byte
H
Print Hello, World!.
• And now with 2 bytes? – Awashi Mar 31 '16 at 13:34
• Unfortunately I can't find a 2 byte palindrome for hello world :( – Blue Mar 31 '16 at 13:36
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https://everything.explained.today/Poincar%C3%A9_group/
|
# Poincaré group explained
The Poincaré group, named after Henri Poincaré (1906),[1] was first defined by Hermann Minkowski (1908) as the group of Minkowski spacetime isometries.[2] It is a ten-dimensional non-abelian Lie group, which is of importance as a model in our understanding the most basic fundamentals of physics.
## Overview
A Minkowski spacetime isometry has the property that the interval between events is left invariant. For example, if everything were postponed by two hours, including the two events and the path you took to go from one to the other, then the time interval between the events recorded by a stop-watch you carried with you would be the same. Or if everything were shifted five kilometres to the west, or turned 60 degrees to the right, you would also see no change in the interval. It turns out that the proper length of an object is also unaffected by such a shift. A time or space reversal (a reflection) is also an isometry of this group.
In Minkowski space (i.e. ignoring the effects of gravity), there are ten degrees of freedom of the isometries, which may be thought of as translation through time or space (four degrees, one per dimension); reflection through a plane (three degrees, the freedom in orientation of this plane); or a "boost" in any of the three spatial directions (three degrees). Composition of transformations is the operation of the Poincaré group, with proper rotations being produced as the composition of an even number of reflections.
In classical physics, the Galilean group is a comparable ten-parameter group that acts on absolute time and space. Instead of boosts, it features shear mappings to relate co-moving frames of reference.
## Poincaré symmetry
Poincaré symmetry is the full symmetry of special relativity. It includes:
The last two symmetries, J and K, together make the Lorentz group (see also Lorentz invariance); the semi-direct product of the translations group and the Lorentz group then produce the Poincaré group. Objects that are invariant under this group are then said to possess Poincaré invariance or relativistic invariance.
10 generators (in four spacetime dimensions) associated with the Poincaré symmetry, by Noether's theorem, imply 10 conservation laws: 1 for the energy, 3 for the momentum, 3 for the angular momentum and 3 for the velocity of the center of mass.[3] [4]
## Poincaré group
The Poincaré group is the group of Minkowski spacetime isometries. It is a ten-dimensional noncompact Lie group. The abelian group of translations is a normal subgroup, while the Lorentz group is also a subgroup, the stabilizer of the origin. The Poincaré group itself is the minimal subgroup of the affine group which includes all translations and Lorentz transformations. More precisely, it is a semidirect product of the translations and the Lorentz group,
R1,3\rtimesO(1,3),
with group multiplication
(\alpha,f)(\beta,g)=(\alpha+f\beta,fg)
.[5]
Another way of putting this is that the Poincaré group is a group extension of the Lorentz group by a vector representation of it; it is sometimes dubbed, informally, as the inhomogeneous Lorentz group. In turn, it can also be obtained as a group contraction of the de Sitter group SO(4,1) ~ Sp(2,2), as the de Sitter radius goes to infinity.
Its positive energy unitary irreducible representations are indexed by mass (nonnegative number) and spin (integer or half integer) and are associated with particles in quantum mechanics (see Wigner's classification).
In accordance with the Erlangen program, the geometry of Minkowski space is defined by the Poincaré group: Minkowski space is considered as a homogeneous space for the group.
In quantum field theory, the universal cover of the Poincaré group
R1,3\rtimesSL(2,C),
which may be identified with the double cover
R1,3\rtimesSpin(1,3),
is more important, because representations of
SO(1,3)
are not able to describe fields with spin 1/2, i.e. fermions. Here
SL(2,C)
is the group of complex
2 x 2
matrices with unit determinant, isomorphic to the Lorentz-signature spin group
Spin(1,3)
.
## Poincaré algebra
The Poincaré algebra is the Lie algebra of the Poincaré group. It is a Lie algebra extension of the Lie algebra of the Lorentz group. More specifically, the proper ($\det\Lambda =1$), orthochronous ($\Lambda^0_ \geq 1$) part of the Lorentz subgroup (its identity component), $SO(1,3)_+^$, is connected to the identity and is thus provided by the exponentiation $\exp(ia_ P^)\exp\left(\frac\omega_ M^\right)$ of this Lie algebra. In component form, the Poincaré algebra is given by the commutation relations:[6] [7] where
P
is the generator of translations,
M
is the generator of Lorentz transformations, and
η
is the
(+,-,-,-)
Minkowski metric (see Sign convention).
The bottom commutation relation is the ("homogeneous") Lorentz group, consisting of rotations, $J_i = \frac\epsilon_ M^$, and boosts, $K_i = M_$. In this notation, the entire Poincaré algebra is expressible in noncovariant (but more practical) language as
[Jm,Pn]=i\epsilonmnkPk~,
[Ji,P0]=0~,
[Ki,Pk]=iηikP0~,
[Ki,P0]=-iPi~,
[Jm,Jn]=i\epsilonmnkJk~,
[Jm,Kn]=i\epsilonmnkKk~,
[Km,Kn]=-i\epsilonmnkJk~,
where the bottom line commutator of two boosts is often referred to as a "Wigner rotation". The simplification $[J_m + iK_m,\, J_n -iK_n] = 0$ permits reduction of the Lorentz subalgebra to $\mathfrak(2) \oplus \mathfrak(2)$ and efficient treatment of its associated representations. In terms of the physical parameters, we have
\left[lH,pi\right]=0
\left[lH,Li\right]=0
\left[lH,Ki\right]=i\hbarcpi
\left[pi,pj\right]=0
\left[pi,Lj\right]=i\hbar\epsilonijkpk
\left[pi,K
j\right]= i\hbar clH\delta
ij
\left[Li,Lj\right]=i\hbar\epsilonijkLk
\left[Li,Kj\right]=i\hbar\epsilonijkKk
\left[Ki,Kj\right]=-i\hbar\epsilonijkLk
The Casimir invariants of this algebra are $P_ P^$ and $W_W^$ where $W_$ is the Pauli–Lubanski pseudovector; they serve as labels for the representations of the group. The Poincaré group is the full symmetry group of any relativistic field theory. As a result, all elementary particles fall in representations of this group. These are usually specified by the four-momentum squared of each particle (i.e. its mass squared) and the intrinsic quantum numbers $J^$, where
J
is the spin quantum number,
P
is the parity and
C
is the charge-conjugation quantum number. In practice, charge conjugation and parity are violated by many quantum field theories; where this occurs,
P
and
C
are forfeited. Since CPT symmetry is invariant in quantum field theory, a time-reversal quantum number may be constructed from those given.
As a topological space, the group has four connected components: the component of the identity; the time reversed component; the spatial inversion component; and the component which is both time-reversed and spatially inverted.[8]
## Other dimensions
The definitions above can be generalized to arbitrary dimensions in a straightforward manner. The d-dimensional Poincaré group is analogously defined by the semi-direct product
IO(1,d-1):=R1,d-1\rtimesO(1,d-1)
with the analogous multiplication
(\alpha,f)(\beta,g)=(\alpha+f\beta,fg)
.
The Lie algebra retains its form, with indices and now taking values between and . The alternative representation in terms of and has no analogue in higher dimensions.
## Super-Poincaré algebra
A related observation is that the representations of the Lorentz group include a pair of inequivalent two-dimensional complex spinor representations
2
and
\overline{2}
whose tensor product
2 ⊗ \overline{2}=3 ⊕ 1
is the adjoint representation. One may identify this last bit with four-dimensional Minkowski space itself (as opposed to identifying it with a spin-1 particle, as would normally be done for a pair of fermions, e.g. a pion being composed of a quark-anti-quark pair). This strongly suggests that it might be possible to extend the Poincaré algebra to also include spinors. This leads directly to the notion of the super-Poincaré algebra. The mathematical appeal of this idea is that one is working with the fundamental representations, instead of the adjoint representations. The physical appeal of this idea is that the fundamental representations correspond to fermions, which are seen in nature. So far, however, the implied supersymmetry here, of a symmetry between spatial and fermionic directions, cannot be seen experimentally in nature. The experimental issue can roughly be stated as the question: if we live in the adjoint representation (Minkowski spacetime), then where is the fundamental representation hiding?
## References
• Book: Group Theory in Physics . Wu-Ki Tung . 1985 . World Scientific Publishing . 9971-966-57-3.
• Book: Weinberg, Steven . The Quantum Theory of Fields . 1 . 1995 . Cambridge University press . Cambridge . 978-0-521-55001-7 . registration .
• Book: Quantum Field Theory . L.H. Ryder . Cambridge University Press . 2nd . 0-52147-8146 . 1996 . 62 .
## Notes and References
1. (Wikisource translation: On the Dynamics of the Electron). The group defined in this paper would now be described as the homogeneous Lorentz group with scalar multipliers.
2. (Wikisource translation: The Fundamental Equations for Electromagnetic Processes in Moving Bodies).
3. Web site: Survey of Symmetry and Conservation Laws: More Poincare. 2021-02-14. frankwilczek.com.
4. Barnett. Stephen M. 2011-06-01. On the six components of optical angular momentum. Journal of Optics. 13. 6. 064010. 10.1088/2040-8978/13/6/064010. 2040-8978.
5. Book: Oblak, Blagoje. BMS Particles in Three Dimensions. 2017-08-01. Springer. 9783319618784. 80. en.
6. Book: General Principles of Quantum Field Theory . N.N. Bogolubov. Springer . 2nd . 0-7923-0540-X . 1989 . 272 .
7. Book: 978-1-13950-4324 . T. Ohlsson. Tommy Ohlsson . Relativistic Quantum Physics: From Advanced Quantum Mechanics to Introductory Quantum Field Theory . Cambridge University Press . 2011 . 10 .
8. Web site: Topics: Poincaré Group. 2021-07-18. www.phy.olemiss.edu.
|
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|
https://converter.ninja/length/millimeters-to-feet/652-mm-to-ft/
|
# 652 millimeters in feet
## Conversion
652 millimeters is equivalent to 2.13910761154856 feet.[1]
## Conversion formula How to convert 652 millimeters to feet?
We know (by definition) that: $1\mathrm{mm}\approx 0.0032808399\mathrm{ft}$
We can set up a proportion to solve for the number of feet.
$1 mm 652 mm ≈ 0.0032808399 ft x ft$
Now, we cross multiply to solve for our unknown $x$:
$x\mathrm{ft}\approx \frac{652\mathrm{mm}}{1\mathrm{mm}}*0.0032808399\mathrm{ft}\to x\mathrm{ft}\approx 2.1391076148\mathrm{ft}$
Conclusion: $652 mm ≈ 2.1391076148 ft$
## Conversion in the opposite direction
The inverse of the conversion factor is that 1 foot is equal to 0.467484662576687 times 652 millimeters.
It can also be expressed as: 652 millimeters is equal to $\frac{1}{\mathrm{0.467484662576687}}$ feet.
## Approximation
An approximate numerical result would be: six hundred and fifty-two millimeters is about two point one four feet, or alternatively, a foot is about zero point four seven times six hundred and fifty-two millimeters.
## Footnotes
[1] The precision is 15 significant digits (fourteen digits to the right of the decimal point).
Results may contain small errors due to the use of floating point arithmetic.
|
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http://hackage-origin.haskell.org/package/passage/candidates/
|
### Candidates for passage
No candidates exist for passage. Upload one for this or another package?
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https://www.physicsforums.com/threads/line-integral-dl-in-spherical-polar-coordinates.302970/
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# Line Integral dl in spherical polar coordinates
1. Mar 27, 2009
### wam_mi
1. The problem statement, all variables and given/known data
Hi guys,
I'm trying to evaluate a line integral, Integration of Vector A dot dL
The vector A was given to be a function of r, theta and fi in spherical polar coordinates.
The question states that an arbitrary closed loop C is the circle parametrised by fi at some arbitrary values of (r, theta).
I would like to ask the following questions:
(i) How do I rewrite dl, the line element, in terms of spherical polar co-ordinates? What does it mean by the closed curve C is the circle parametrised by fi at some arbitrary values of (r, theta). How does it change my dl if C wasn't a circle?
(ii) What are the limits of the line integral?
Thanks guys!
2. Relevant equations
3. The attempt at a solution
Can you offer guidance or do you also need help?
Similar Discussions: Line Integral dl in spherical polar coordinates
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http://physics.stackexchange.com/questions/65782/does-the-existence-of-higgs-imply-the-existence-of-magnetic-monopoles
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# Does the existence of Higgs imply the existence of Magnetic Monopoles?
I am aware that in theories with spontaneous symmetry breaking, Magnetic Monopoles can exist as topological solitons. Can the same be done with the Standard Model gauge group. I am familiar with the contents of 't Hooft's paper Magnetic Monopoles in Unified Gauge theories. But the analysis in that paper is done for the $\operatorname{SO}(3)$ gauge group.
Is there a similar analysis for the standard model gauge group? Does the discovery of Higgs particle imply the existence of magnetic monopoles as topological solitons, and magnetic charge being treated as a topological charge?
-
No, I believe the Standard Model does not predict monopoles as a result of symmetry breaking. This is because the symmetry breaking $\mathrm{SU(2)} \times \mathrm{U(1)} \rightarrow \mathrm{U(1)}$ does not allow for topological solitons to exist.
Edit: $\pi_2(\mathrm{SU(2)} \times \mathrm{U(1)}/\mathrm{U(1))}=\pi_2(S^3)=0$
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https://crypto.stackexchange.com/questions/70232/does-encoding-a-secret-affect-security
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# Does encoding a secret affect security?
My question is simple. I have a secret that is generated with a 10 byte long pseudorandom generator library (e.g. Java's SecureRandom), that in theory provides a security equivalent to $$2^{40}$$ (birthday bound). This secret is encoded afterwards (e.g. Base64). This is supposed to reduce entropy, while extending the string lenght.
If I want to brute force the secret, does the encoding have any negative impact on the protection? (in other words, does it facilitate the brute forcing at all?) My intuition is that the security is not affected, but I learnt to be extra cautious with this sort of things.
• How do you figure the entropy reduction? Are you talking the reduced entropy rate of 8 bits/byte to 6 bits/character? May 1 '19 at 22:27
• By the way, 'denigrate' means to say something is bad, but does not mean that description is correct. In fact something that is denigrated is usually in fact good. If you mean 'reduce', say 'reduce'. May 2 '19 at 1:15
• Yes, I mean the entropy reduction in terms of entropy per byte: where there could be 256 possibilities before now this set is reduced. But of course, this increases the string length May 2 '19 at 7:04
• You are right, @dave_thompson_085, perhaps I have not chosen the most accurate verb May 2 '19 at 7:06
A byte is 8 bits; 10 random bytes are therefore 80 random bits, which is $$2^{80}$$ equiprobable alternatives (not $$2^{40}$$), which is 80 bits of entropy. (Unless your 10 byte random string is actually an ASCII representation of a 40-bit hexadecimal value; since SecureRandom outputs full range byte[] I'll assume it's not that.)
This secret is encoded afterwards (e.g. Base64). This is supposed to reduce entropy, while extending the string length.
This "entropy reduction" isn't real. Any Base64 encoder is a one-to-one function—each of the $$2^{80}$$ inputs in your example is mapped to a unique output. There are therefore $$2^{80}$$ unique possible outcomes as well, each one equally likely, and thus 80 bits of entropy like originally.
What's probably confusing you is that the binary representation of the Base64-encoded string is longer than 80 bits, but it's not made of uniform random bits, so in that sense it's not a full-entropy string—the 14-ish bytes in the Base64 string are 112 bits long but would only collectively have 80 bits of entropy.
If I want to brute force the secret, does the encoding has any negative impact on the protection?
Not really. Again, $$2^{80}$$ possible outcomes, all of them equally likely.
• You are forgetting the birthday bound to calculate $2^{80}$, don't you? May 2 '19 at 7:00
• Your answer is what my intuition says, and what seems correct (except from the fact that you are assuming more security - $2^{80}$ than what I think it has - $2^{40}$). Note that I have not accepted yet because I am looking for a potential smart answer that can state the opposite (in cryptography, many security breaks are counterintuitive) May 2 '19 at 8:03
• @user1156544 80 bits of entropy provide 40 bits of security against collisions when applying the birthday paradox directly. They are still 80 bits of entropy. Collision attacks may, or may not, be relevant depending on the context of the protocol or algorithm being studied. May 2 '19 at 9:14
• Agree. That is why I never said it has an entropy of $2^{40}$ but a provided security equivalent to $2^{40}$. May 2 '19 at 9:39
• @user1156544 It only provides 40 bits of security in few contexts. This result cannot be generalized like you do. Even the reduction to half the bits is just a rule of thumb and cannot be applied when one seeks a probability of collisions of 2^-32. May 2 '19 at 10:00
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https://www.aimsciences.org/article/doi/10.3934/jimo.2021026?viewType=html
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# American Institute of Mathematical Sciences
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March 2022, 18(2): 1425-1437. doi: 10.3934/jimo.2021026
## CCR model-based evaluation on the effectiveness and maturity of technological innovation
1 The Department of Finance, School of Business, China University of Political Science and Law, Beijing, 100088, China 2 The Physics Department, School of Arts and Sciences, Boston University, Boston, MA 02215, USA
* Corresponding author: Liling Lin and Linfeng Zhao
Received June 2020 Revised December 2020 Published March 2022 Early access February 2021
As there are many indexes for evaluating technological innovation in enterprises, it is hard to quantify all those indexes. Therefore, common evaluation methods cannot be applied to solve the absolute value of the evaluation indexes. Therefore, this study used the nonparametric CCR model based on input-output to estimate the relative value of evaluation index, and took dual programming tool to obtain the judgment basis for the most effective and optimal solution. Based on the software evaluation criteria, this paper proposed the concept of "maturity in technological innovation, " its four levels, and an evaluation standard for maturity. Based on the homogeneity, the paper selected four Beijing enterprises as evaluation samples. After comparing and analyzing the efficiency, scale return, production surface projection and maturity, we found that the evaluation results conform to the reality of sampling enterprises. CCR model was used to evaluate decision-making units with multiple inputs and outputs. The results show that this method can help accurately obtain the relative order and the enterprises' ability to make technological innovation. Thus, CCR model is able to help enterprises formulate policies on technological innovation.
Citation: Liling Lin, Linfeng Zhao. CCR model-based evaluation on the effectiveness and maturity of technological innovation. Journal of Industrial and Management Optimization, 2022, 18 (2) : 1425-1437. doi: 10.3934/jimo.2021026
##### References:
[1] F. T. Akyildiz and K. Vajravelu, Galerkin-chebyshev pseudo spectral method and a split step new approach for a class of two dimensional semi-linear parabolic equations of second order, Applied Mathematics and Nonlinear Sciences, 3 (2018), 255-264. doi: 10.21042/AMNS.2018.1.00019. [2] E. Bohlool and T. Mehdi, Efficiency bounds and efficiency classifications in imprecise DEA: An extension, Journal of the Operational Research Society, 7 (2019), 30-35. [3] M. Idi and B. M. Aliyu, Cyber security capability maturity model for network system, International Journal of Development Research, 6 (2019), 37-41. [4] X. Liu, C-W. Ni and L-Y. Zhang, Durability assessment of lightweight cellular concrete in sub-grade by the method of analytic hierarchy process combined with fuzzy comprehensive evaluation, Mathematical Problems in Engineering, 2019 (2019), 1-10. [5] J-C. Lu and G- W Han, Osculating value method of business technology innovation capacity evaluation, Science Research Management, 1 (2002), 54-57. [6] T. Madjid, K-D. Kaveh, S. A. J. Francisco and H. Amineh, A fuzzy multi-objective multi-period network DEA model for efficiency measurement in oil refineries, Computers and Industrial Engineering, 9 (2019), 143-155. [7] R. T. Md, N. Rasmus and K. A. Md, Efficiency and production environmental heterogeneity in aquaculture: A meta-frontier DEA approach, Aquaculture, 6 (2019), 140-148. [8] L. Nils and S. Alexander, Modeling time-dependent randomness in stochastic dual dynamic programming, European Journal of Operational Research, 2 (2019), 650-661. [9] L. L. Pan and L. X. Sun, Modeling time-dependent randomness in stochastic dual dynamic programming, Science and Technology Management Research, 7 (2019), 32-37. [10] C. Rojas and J. Belmonte-Beitia, Optimal control problems for differential equations applied to tumor growth: State of the art, Applied Mathematicsand Nonlinear Sciences, 3 (2018), 375-402. doi: 10.21042/AMNS.2018.2.00029. [11] Y-Z. Tang and S-G. Zhou, Grey synthetic evaluation of enterprise' technological innovation capacity, Science and Technology Progress and Policy, 5 (1999), 46-81. [12] A. Yokus and Gülbahar, Numerical solutions with linearization techniques of the fractional harry dym equation, Applied Mathematicsand Nonlinear Sciences, 4 (2018), 35-42. doi: 10.2478/AMNS.2019.1.00004. [13] L-F. Zhao, X. Zhou, Y. Du and L-D. Tan, DEA comprehensive evaluation on enterprise's technology innovation capacity, China Science Forum, 6 (2007), 49-52. [14] Y-P. Zhou, Neural network experience analysis on enterprise technological innovation ability, Science and Technology Progress and Policy, 17 (2000), 62-63.
show all references
##### References:
[1] F. T. Akyildiz and K. Vajravelu, Galerkin-chebyshev pseudo spectral method and a split step new approach for a class of two dimensional semi-linear parabolic equations of second order, Applied Mathematics and Nonlinear Sciences, 3 (2018), 255-264. doi: 10.21042/AMNS.2018.1.00019. [2] E. Bohlool and T. Mehdi, Efficiency bounds and efficiency classifications in imprecise DEA: An extension, Journal of the Operational Research Society, 7 (2019), 30-35. [3] M. Idi and B. M. Aliyu, Cyber security capability maturity model for network system, International Journal of Development Research, 6 (2019), 37-41. [4] X. Liu, C-W. Ni and L-Y. Zhang, Durability assessment of lightweight cellular concrete in sub-grade by the method of analytic hierarchy process combined with fuzzy comprehensive evaluation, Mathematical Problems in Engineering, 2019 (2019), 1-10. [5] J-C. Lu and G- W Han, Osculating value method of business technology innovation capacity evaluation, Science Research Management, 1 (2002), 54-57. [6] T. Madjid, K-D. Kaveh, S. A. J. Francisco and H. Amineh, A fuzzy multi-objective multi-period network DEA model for efficiency measurement in oil refineries, Computers and Industrial Engineering, 9 (2019), 143-155. [7] R. T. Md, N. Rasmus and K. A. Md, Efficiency and production environmental heterogeneity in aquaculture: A meta-frontier DEA approach, Aquaculture, 6 (2019), 140-148. [8] L. Nils and S. Alexander, Modeling time-dependent randomness in stochastic dual dynamic programming, European Journal of Operational Research, 2 (2019), 650-661. [9] L. L. Pan and L. X. Sun, Modeling time-dependent randomness in stochastic dual dynamic programming, Science and Technology Management Research, 7 (2019), 32-37. [10] C. Rojas and J. Belmonte-Beitia, Optimal control problems for differential equations applied to tumor growth: State of the art, Applied Mathematicsand Nonlinear Sciences, 3 (2018), 375-402. doi: 10.21042/AMNS.2018.2.00029. [11] Y-Z. Tang and S-G. Zhou, Grey synthetic evaluation of enterprise' technological innovation capacity, Science and Technology Progress and Policy, 5 (1999), 46-81. [12] A. Yokus and Gülbahar, Numerical solutions with linearization techniques of the fractional harry dym equation, Applied Mathematicsand Nonlinear Sciences, 4 (2018), 35-42. doi: 10.2478/AMNS.2019.1.00004. [13] L-F. Zhao, X. Zhou, Y. Du and L-D. Tan, DEA comprehensive evaluation on enterprise's technology innovation capacity, China Science Forum, 6 (2007), 49-52. [14] Y-P. Zhou, Neural network experience analysis on enterprise technological innovation ability, Science and Technology Progress and Policy, 17 (2000), 62-63.
Input and output of evaluation departments
No. Weight Decision-making unit 1 2 ... j ... n Input data 1 $v_{1}$ $x_{11}$ $x_{12}$ ... $x_{1j}$ ... $x_{1n}$ 2 $v_{2}$ $x_{21}$ $x_{22}$ ... $x_{2j}$ ... $x_{2n}$ ... ... ... ... $m$ $v_{m}$ $x_{m1}$ $x_{m2}$ ... $x_{mj}$ ... $x_{mn}$ Output data 1 $u_{1}$ $y_{11}$ $y_{12}$ ... $y_{1j}$ ... $y_{1n}$ 2 $u_{2}$ $y_{21}$ $y_{22}$ ... $y_{2j}$ ... $y_{2n}$ ... ... ... ... $s$ $u_{s}$ $y_{s1}$ $y_{s2}$ ... $y_{sj}$ ... $y_{sn}$
No. Weight Decision-making unit 1 2 ... j ... n Input data 1 $v_{1}$ $x_{11}$ $x_{12}$ ... $x_{1j}$ ... $x_{1n}$ 2 $v_{2}$ $x_{21}$ $x_{22}$ ... $x_{2j}$ ... $x_{2n}$ ... ... ... ... $m$ $v_{m}$ $x_{m1}$ $x_{m2}$ ... $x_{mj}$ ... $x_{mn}$ Output data 1 $u_{1}$ $y_{11}$ $y_{12}$ ... $y_{1j}$ ... $y_{1n}$ 2 $u_{2}$ $y_{21}$ $y_{22}$ ... $y_{2j}$ ... $y_{2n}$ ... ... ... ... $s$ $u_{s}$ $y_{s1}$ $y_{s2}$ ... $y_{sj}$ ... $y_{sn}$
Data of sample enterprises
Enter-prises Years R & D funds/product sales revenue (A13) (%)x1 Number of full-time R&D personnel /number of employees (A22) (%)x2 Technology introduction and transformation cost/ product sales revenue (A31) (%)x3 Annual per capita income of R&D personnel /annual per capita income of enterprises (B21) X4 Innovation strategy (B11) X5 Technical level (C11) x6 Number of patents and proprietary technology (C41) x7 Equipment level (D11) x8 Marketing costs for new products /new product sales revenue (E32) (%) x9 Number of full -time sales personnel/ number of employees (E42) x10 New product sales revenue /total product sales revenue (F12) (%) Y1 Enterprise I 01 3.14 13.85 5.38 1.01 75 1 15 0.8 3.81 0.24 24.94 02 3.37 14.31 3.84 1.01 80 1 15 0.8 5.47 0.25 36.04 03 3.65 15.98 6.43 1.11 80 1 15 0.8 6.34 0.26 35.51 04 5.05 17.44 1.1 1.1 85 1 15 0.8 4.29 0.27 35.27 05 5.21 19.19 1.4 1.07 90 1 15 0.8 3.11 0.29 35.35 Enterprise II 01 3.47 14.33 19.69 1.21 70 0.4 9 0.6 20 0.19 7.3 02 4.24 14.51 26.63 1.32 70 0.4 9 0.6 27.91 0.2 8.12 03 4.55 14.63 35.06 1.05 70 0.4 9 0.6 34.12 0.22 11.17 04 3.37 15.66 4.84 1.12 70 0.4 10 0.6 32.12 0.22 13.36 05 3.13 16.05 3.2 1.19 70 0.6 10 0.6 29.66 0.22 13 Enterprise III 01 9.1 7.11 3.17 1.51 80 0.6 6 0.4 13.55 0.1 2.16 02 10.94 7.23 4.66 1.62 80 0.6 6 0.4 14.21 0.1 2.22 03 29.66 7.39 2.65 1.68 80 0.6 6 0.4 15.33 0.1 3.27 04 20.91 7.43 3.05 1.65 80 0.6 6 0.4 17.17 0.1 4.68 05 15.66 7.51 0.74 1.69 80 0.6 6 0.4 15.61 0.1 4.95 Enterprise III 01 2.96 22 21.45 1.22 70 0.4 5 0.4 13.23 0.3 8.085 02 3.36 25 0.48 1.52 70 0.4 5 0.4 8.07 0.3 10.01 03 3.52 21 0.76 1.4 75 0.4 5 0.4 7.13 0.3 15.575 04 4.36 29 3.35 1.29 80 0.4 5 0.4 3.9 0.3 22.14 05 7.47 27 2.35 1.06 80 0.4 5 0.4 2.38 0.3 25.69
Enter-prises Years R & D funds/product sales revenue (A13) (%)x1 Number of full-time R&D personnel /number of employees (A22) (%)x2 Technology introduction and transformation cost/ product sales revenue (A31) (%)x3 Annual per capita income of R&D personnel /annual per capita income of enterprises (B21) X4 Innovation strategy (B11) X5 Technical level (C11) x6 Number of patents and proprietary technology (C41) x7 Equipment level (D11) x8 Marketing costs for new products /new product sales revenue (E32) (%) x9 Number of full -time sales personnel/ number of employees (E42) x10 New product sales revenue /total product sales revenue (F12) (%) Y1 Enterprise I 01 3.14 13.85 5.38 1.01 75 1 15 0.8 3.81 0.24 24.94 02 3.37 14.31 3.84 1.01 80 1 15 0.8 5.47 0.25 36.04 03 3.65 15.98 6.43 1.11 80 1 15 0.8 6.34 0.26 35.51 04 5.05 17.44 1.1 1.1 85 1 15 0.8 4.29 0.27 35.27 05 5.21 19.19 1.4 1.07 90 1 15 0.8 3.11 0.29 35.35 Enterprise II 01 3.47 14.33 19.69 1.21 70 0.4 9 0.6 20 0.19 7.3 02 4.24 14.51 26.63 1.32 70 0.4 9 0.6 27.91 0.2 8.12 03 4.55 14.63 35.06 1.05 70 0.4 9 0.6 34.12 0.22 11.17 04 3.37 15.66 4.84 1.12 70 0.4 10 0.6 32.12 0.22 13.36 05 3.13 16.05 3.2 1.19 70 0.6 10 0.6 29.66 0.22 13 Enterprise III 01 9.1 7.11 3.17 1.51 80 0.6 6 0.4 13.55 0.1 2.16 02 10.94 7.23 4.66 1.62 80 0.6 6 0.4 14.21 0.1 2.22 03 29.66 7.39 2.65 1.68 80 0.6 6 0.4 15.33 0.1 3.27 04 20.91 7.43 3.05 1.65 80 0.6 6 0.4 17.17 0.1 4.68 05 15.66 7.51 0.74 1.69 80 0.6 6 0.4 15.61 0.1 4.95 Enterprise III 01 2.96 22 21.45 1.22 70 0.4 5 0.4 13.23 0.3 8.085 02 3.36 25 0.48 1.52 70 0.4 5 0.4 8.07 0.3 10.01 03 3.52 21 0.76 1.4 75 0.4 5 0.4 7.13 0.3 15.575 04 4.36 29 3.35 1.29 80 0.4 5 0.4 3.9 0.3 22.14 05 7.47 27 2.35 1.06 80 0.4 5 0.4 2.38 0.3 25.69
Definition of input and output indicators
Types Names Code Definition Unit Enterprise III X1 A13 R & D funds / product sales revenue % X2 A22 Number of full-time R & D personnel / number of employees % X3 A31 Technology introduction and transformation cost / product sales revenue % X4 B21 Annual per capita income of R & D personnel/ annual per capita income of enterprises % X5 B11 Innovation strategy Point X6 C11 Technical level= 1 × international level + 0.6 × domestic level + 0.3 × enterprise level X7 C41 Number of patents and proprietary technology Piece X8 D11 Equipment level = 1 × international advanced level (%) + 0.8 × international general level (%) + 0.6 × domestic advanced level (%) + 0.4 × domestic general level (%) + 0.2 × others X9 E32 Marketing costs for new products/new product sales revenue % X10 E42 Number of full-time sales personnel/ number of employees Output variable Y1 F12 New product sales revenue/total product sales revenue %
Types Names Code Definition Unit Enterprise III X1 A13 R & D funds / product sales revenue % X2 A22 Number of full-time R & D personnel / number of employees % X3 A31 Technology introduction and transformation cost / product sales revenue % X4 B21 Annual per capita income of R & D personnel/ annual per capita income of enterprises % X5 B11 Innovation strategy Point X6 C11 Technical level= 1 × international level + 0.6 × domestic level + 0.3 × enterprise level X7 C41 Number of patents and proprietary technology Piece X8 D11 Equipment level = 1 × international advanced level (%) + 0.8 × international general level (%) + 0.6 × domestic advanced level (%) + 0.4 × domestic general level (%) + 0.2 × others X9 E32 Marketing costs for new products/new product sales revenue % X10 E42 Number of full-time sales personnel/ number of employees Output variable Y1 F12 New product sales revenue/total product sales revenue %
Optimal solution and relaxation variables
Enterprises Year $\theta$ $S1^{-}$ $S2^{-}$ $S3^{-}$ $S4^{-}$ $S5^{-}$ $S6^{-}$ $S7^{-}$ $S8^{-}$ $S9^{-}$ $S10^{-}$ $S1^{+}$ Enterprise 1 01 0.8696334 0 1.06315 2.51657 0.16280 7.44845 0.17362 2.60427 0.13889 0 0.02634 0 02 1.000000 0 0 0 0 0 0 0 0 0 0 0 03 0.9852941 0.27588 1.64544 2.55191 0.09853 0 0 0 0 0.85721 0.00985 0 04 1.000000 0 0 0 0 0 0 0 0 0 0 0 05 1.000000 0 0 0 0 0 0 0 0 0 0 0 Enterprise 2 01 0.3938900 0 0 6.98602 0.20658 7.49104 0 1.33744 0.09783 6.92850 0.00430 0 02 0.4257631 0.15493 0 10.54098 0.27466 7.73962 0 1.45311 0.10515 10.91772 0.00741 0 03 0.5837402 0.37323 0 19.37040 0.21680 10.45333 0 1.99557 0.14390 18.59308 0.02118 0 04 0.7169654 0 0 1.94594 0.26629 11.90772 0 3.18738 0.17519 21.15136 0.02213 0 05 0.5354496 0 0 0.18736 0.16405 3.44490 0 0.70910 0.05036 13.86115 0.00275 0 Enterprise 3 01 0.1498335 1.16151 0.20767 0.24483 0.16572 7.19201 0.02997 0 0.01199 1.70241 0 0 02 0.1539956 1.47713 0.23192 0.48108 0.18726 7.39179 0.03080 0 0.01232 1.85134 0 0 03 0.2268313 6.42205 0.37790 0.25269 0.28944 10.88790 0.04537 0 0.01815 2.98102 0 0 04 0.3246393 6.35059 0.55383 0.49150 0.40450 15.58269 0.06493 0 0.02597 4.86375 0 0 05 0.3677099 5.12719 0.46604 0 0.47199 17.78455 0.08123 0.11527 0.03556 5.09078 0 0 Enterprise 4 01 0.4552423 0 1.58449 8.64749 0.15586 5.94956 0.01313 0 0.02625 4.65633 0.04266 0 02 0.7785724 0.89338 11.53132 0 0.66614 21.97158 0.03695 0 0.07390 3.89102 0.11639 0 03 1.000000 0 0 0 0 0 0 0 0 0 0 0 04 1.000000 0 0 0 0 0 0 0 0 0 0 0 05 1.000000 0 0 0 0 0 0 0 0 0 0 0
Enterprises Year $\theta$ $S1^{-}$ $S2^{-}$ $S3^{-}$ $S4^{-}$ $S5^{-}$ $S6^{-}$ $S7^{-}$ $S8^{-}$ $S9^{-}$ $S10^{-}$ $S1^{+}$ Enterprise 1 01 0.8696334 0 1.06315 2.51657 0.16280 7.44845 0.17362 2.60427 0.13889 0 0.02634 0 02 1.000000 0 0 0 0 0 0 0 0 0 0 0 03 0.9852941 0.27588 1.64544 2.55191 0.09853 0 0 0 0 0.85721 0.00985 0 04 1.000000 0 0 0 0 0 0 0 0 0 0 0 05 1.000000 0 0 0 0 0 0 0 0 0 0 0 Enterprise 2 01 0.3938900 0 0 6.98602 0.20658 7.49104 0 1.33744 0.09783 6.92850 0.00430 0 02 0.4257631 0.15493 0 10.54098 0.27466 7.73962 0 1.45311 0.10515 10.91772 0.00741 0 03 0.5837402 0.37323 0 19.37040 0.21680 10.45333 0 1.99557 0.14390 18.59308 0.02118 0 04 0.7169654 0 0 1.94594 0.26629 11.90772 0 3.18738 0.17519 21.15136 0.02213 0 05 0.5354496 0 0 0.18736 0.16405 3.44490 0 0.70910 0.05036 13.86115 0.00275 0 Enterprise 3 01 0.1498335 1.16151 0.20767 0.24483 0.16572 7.19201 0.02997 0 0.01199 1.70241 0 0 02 0.1539956 1.47713 0.23192 0.48108 0.18726 7.39179 0.03080 0 0.01232 1.85134 0 0 03 0.2268313 6.42205 0.37790 0.25269 0.28944 10.88790 0.04537 0 0.01815 2.98102 0 0 04 0.3246393 6.35059 0.55383 0.49150 0.40450 15.58269 0.06493 0 0.02597 4.86375 0 0 05 0.3677099 5.12719 0.46604 0 0.47199 17.78455 0.08123 0.11527 0.03556 5.09078 0 0 Enterprise 4 01 0.4552423 0 1.58449 8.64749 0.15586 5.94956 0.01313 0 0.02625 4.65633 0.04266 0 02 0.7785724 0.89338 11.53132 0 0.66614 21.97158 0.03695 0 0.07390 3.89102 0.11639 0 03 1.000000 0 0 0 0 0 0 0 0 0 0 0 04 1.000000 0 0 0 0 0 0 0 0 0 0 0 05 1.000000 0 0 0 0 0 0 0 0 0 0 0
Maturity of technological innovation of sample enterprises
Enterprises Year DEA optimal solution Technological innovation maturity Enterprise 1 2014 0.8696334 Less maturity 2015 1.000000 Full maturity 2016 0.9852941 Less maturity 2017 1.000000 Full maturity 2018 1.000000 Full maturity Enterprise 2 2014 0.39389 Immaturity 2015 0.425763 Immaturity 2016 0.58374 Less maturity 2017 0.716965 Less maturity 2018 0.53545 Less maturity Enterprise 3 2014 0.149834 Immaturity 2015 0.153996 Immaturity 2016 0.226831 Immaturity 2017 0.324639 Immaturity 2018 0.36771 Immaturity Enterprise 4 2014 0.455242 Immaturity 2015 0.778572 Less maturity 2016 1.000000 Full maturity 2017 1.000000 Full maturity 2018 1.000000 Full maturity
Enterprises Year DEA optimal solution Technological innovation maturity Enterprise 1 2014 0.8696334 Less maturity 2015 1.000000 Full maturity 2016 0.9852941 Less maturity 2017 1.000000 Full maturity 2018 1.000000 Full maturity Enterprise 2 2014 0.39389 Immaturity 2015 0.425763 Immaturity 2016 0.58374 Less maturity 2017 0.716965 Less maturity 2018 0.53545 Less maturity Enterprise 3 2014 0.149834 Immaturity 2015 0.153996 Immaturity 2016 0.226831 Immaturity 2017 0.324639 Immaturity 2018 0.36771 Immaturity Enterprise 4 2014 0.455242 Immaturity 2015 0.778572 Less maturity 2016 1.000000 Full maturity 2017 1.000000 Full maturity 2018 1.000000 Full maturity
Adjustment range of evaluation indexes of enterprise 1
Types Names Definition Change in value (unit) Adjusted values (unit) Input variables X1 R & D funds/product sales revenue -0.409351124 (%) 2.730648876 (%) X2 Number of full-time R & D personnel/ number of employees -2.86872741 (%) 10.98127259 (%) X3 Technology introduction and transformation cost / product sales revenue -3.217942308 (%) 2.162057692 (%) X4 Annual per capita income of R & D personnel / annual per capita income of enterprises -0.294470266 (%) 0.715529734 (%) X5 Innovation strategy -17.225945 (Score) 57.774055 (Score) X6 Technical level -0.3039866 0.6960134 X7 Number of patents and proprietary technology -4.559769 10.440231 X8 Equipment level -0.24318328 0.55681672 X9 Marketing costs for new products / new product sales revenue -0.496696746 (%) 3.313303254 (%) X10 Number of full-time sales personnel / number of employees -0.057627984 0.182372016 Output variable Y1 New product sales revenue / total product sales revenue 0 (%) 24.94
Types Names Definition Change in value (unit) Adjusted values (unit) Input variables X1 R & D funds/product sales revenue -0.409351124 (%) 2.730648876 (%) X2 Number of full-time R & D personnel/ number of employees -2.86872741 (%) 10.98127259 (%) X3 Technology introduction and transformation cost / product sales revenue -3.217942308 (%) 2.162057692 (%) X4 Annual per capita income of R & D personnel / annual per capita income of enterprises -0.294470266 (%) 0.715529734 (%) X5 Innovation strategy -17.225945 (Score) 57.774055 (Score) X6 Technical level -0.3039866 0.6960134 X7 Number of patents and proprietary technology -4.559769 10.440231 X8 Equipment level -0.24318328 0.55681672 X9 Marketing costs for new products / new product sales revenue -0.496696746 (%) 3.313303254 (%) X10 Number of full-time sales personnel / number of employees -0.057627984 0.182372016 Output variable Y1 New product sales revenue / total product sales revenue 0 (%) 24.94
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https://pdfkul.com/information-acquisition-and-strategic-sequencing-in-_59bbfecc1723dd99e8792bbe.html
|
Strategic Ignorance in Sequential Procurement∗ Silvana Krasteva Department of Economics Texas A&M University Allen 3054 College Station, TX 77843 E-mail: [email protected]
Huseyin Yildirim Department of Economics Duke University Box 90097 Durham, NC 27708 E-mail: [email protected]
March 17, 2017
1
Introduction
The procurement of complementary goods and services often entails dealing with independent sellers. Examples include: a real estate developer buying up adjacent parcels from different landowners; an employer recruiting a team of employees; a lobbyist securing bipartisan support; and a vaccine manufacturer obtaining required antigens from patent holders. In many cases, the buyer needs to deal with the sellers bilaterally – perhaps, convening multiple sellers is infeasible, or the sellers fear leaking business plans to the rivals. Given the ∗ Previously entitled “Information Acquisition and Strategic Sequencing in Bilateral Trading: Is Ignorance Bliss?” We thank seminar participants at the Duke Theory Lunch, Econometric Society Summer Meetings, 12th International Industrial Organization Conference, 25th International Conference on Game Theory, Texas Theory Camp, UC-Berkeley, UC-San Diego, and University of Toronto for comments. All remaining errors are ours.
1
an interesting discussion and further applications of sequencing in bilateral trading, see Sebenius (1996) and Wheeler (2005). 2 In particular, the buyer’s stand-alone valuations are assumed to be more uncertain than her joint valuation. For instance, a developer may be less sure about the success of a smaller shopping mall built on a single parcel; a lobbyist may be more worried about passage of the legislation through only one-party endorsement; or a vaccine manufacturer may be more uncertain about the effectiveness of the vaccine that uses only a subset of the required antigens. 3 For instance, an employer can assign scheduling of job interviews to an (uninformed) administrative assistant or ask job candidates to pick an interview slot from available ones. In some applications, the buyer’s sheer concern
2
3
4
The strategic value of being uninformed has also been indicated in other contexts. For instance, Carrillo and Mariotti (2000) argue that a decision-maker with time-inconsistent preferences may choose to remain ignorant of the state to control future consumption. In a principal-agent framework, Riordan (1990), Cremer (1995), Dewatripont and Maskin (1995) and Taylor and Yildirim (2011), among others, show that an uninformed principal may better motivate an agent while Kessler (1998) makes a similar point for the agent who may stay ignorant to obtain a more favorable contract. Perhaps, in this vein, papers closest in spirit to ours are those that incorporate signaling. Among them, Kaya (2010) examines a repeated contracting model without commitment and finds that the principal may delay information acquisition to avoid costly signaling through contracts. In a duopoly setting with role choice, Mailath (1993) and Daughety and Reinganum (1994) show that the choice of production period (as well as production level) may have signaling value and dampen incentives to acquire information. The issue of signaling in our setting is very different from these models, and the value of information critically depends on the prior belief in a non-monotonic way. The rest of the paper is organized as follows. The next section sets up the base model, followed by the equilibrium characterization with exogenous information in Section 3. Section 4 endogenizes information. We explore several extensions and variations in Section 5 and the case of substitutes in Section 6. Section 7 concludes. The proofs of formal results are relegated to an appendix.
2
Base model
A risk-neutral buyer (b) aims to purchase two complementary goods such as adjacent land parcels from two risk-neutral sellers (si , i = 1, 2). It is commonly known that the buyer’s joint value is 1, while her stand-alone value for good i, vi , is an independent draw from a nondegenerate Bernoulli distribution:11 Pr{vi = 0} = q ∈ (0, 1) and Pr{vi =
1 2}
= 1 − q.
We say that as q increases, goods become stronger complements for the buyer. In particular, with probability q2 goods are believed to be perfect complements. The outside option of each player is normalized to 0. The buyer meets with the sellers only once and in the sequence of her choice: s1 → s2 or acquisition (hence the signaling and strategic ignorance issues here) and explore instead the optimal sequencing of the sellers with ex ante heterogenous bargaining powers – i.e., the probability of making the offer. 11 For expositional purposes, we take v ∈ {0, 1 } throughout, but our results, especially that on the negative i 2 value of information, would generalize to vi ∈ {v L , v H } where 0 ≤ v L < v H ≤ 12 ; see Appendix B.
5
rule out c = 0 in the analysis to avoid a trivial equilibrium multiplicity when the value of information is exactly zero, though some of our key results will hold even for c = 0.
6
tial for an uninformed buyer. Finally, we restrict attention to one-time bilateral interactions; ¨ see Horner and Vieille (2009) for a similar restriction. This greatly simplifies the analysis with multiple sellers and is reasonable if the buyer has a limited time to undertake the project or an employer is in urgent need of filling vacancies. In Section 5, we relax many of our modeling assumptions. We begin our analysis with an exogenous information structure and then determine the value of being informed for the buyer. Without loss of generality, we re-label the sellers so that seller 1 refers to the first or leading seller in the sequence unless stated otherwise.
3
Informed vs. uninformed sequencing
Suppose that it is commonly known whether the buyer sequences informed (I) or uninformed (U). Given ex ante identical sellers, sequencing is inconsequential for an uninformed buyer. For an informed buyer, let θ1 (vi , v−i ) be the probability that the first (-place) seller has standalone value vi . To ease our analysis, we restrict attention to symmetric equilibria, in which equal sellers are treated equally: θ1 (v, v) = 12 , which reduces sequencing decision to choosing θ1 ( 21 , 0). Let h ∈ {0, 1} indicate the buyer’s purchase history and ( p1z , p2z (h)) denote the corresponding pair of prices where z = I, U. Our first result shows that under weak complements, equilibrium prices do not respond to informed sequencing. Lemma 1 Suppose q ≤ 12 . In equilibrium, (a) ( p1z , p2z (h)) = ( 12 , 12 ) for all z and h, and (b) the buyer purchases the bundle with certainty. If goods were independent, i.e., q = 0, each seller would post his monopoly price of 21 , inducing a joint purchase irrespective of the buyer’s information. Lemma 1 implies that the same applies to weak complements, q ≤ 12 . Lemma 1 is, however, uninteresting for our purposes as it trivially rules out information acquisition. For q > 12 , Proposition 1 characterizes the equilibrium in which prices do respond to the buyer’s information and thus the focus of our ensuing analysis.13
13 As with most signaling games, for q > 1 , there are also trivial equilibria in which the buyer always ignores 2 her private information when sequencing and has no incentive to acquire information as a result.
7
1 I Proposition 1 Suppose q > 12 . In equilibrium, pU 2 ( h = 0) = p2 ( h = 0) = 2 . Moreover, for
(a) an uninformed buyer: 1− q with prob. 2 U p1 = 1 with prob. 2
1− q q
and 2q−1 q
(b) an informed buyer: p1I = p2I (h = 1) =
p1I =
1− q2 2 1 2
with prob. with prob.
and θ1 ( 12 , 0) = 1 for q >
1− q2 q2 2q2 −1
1 2
pU 2 (h
= 1) =
and θ1 ( 21 , 0) >
and p2I (h = 1) =
q2
1 2
1 2
1 with prob.
with prob. 1 − q
for q ≤
√1 ; 2
q;
and
1 2
1 with prob.
with prob. 1 − q2 q2 ,
√1 . 2
(c) Demand: A buyer with v1 = 0 accepts only the low p1z but all p2z (h = 1) whereas a buyer with v1 =
1 2
accepts all p1z but only the low p2z (h = 1).
To understand Proposition 1, notice that with sunk payments, a key strategic concern for the buyer is being held up by the second seller. Consider an uninformed buyer. Upon observing the purchase history, the second seller optimally charges the buyer’s marginal value from the bundle, which is either
1 2
or 1. He must strictly mix between these prices; otherwise,
a sure price of 1 would strictly discourage a low value buyer from acquiring the first good and lead the second seller to reduce his price to
1 2
whereas a sure price of
1 2
would guarantee
the sale of the first good and encourage the second seller to raise his price to 1 given that the prior strictly favors a low value buyer, q > 12 . Not surprisingly, seller 2 mixes according to the prior on the first good and thus stochastically increases his price with the probability of a low value buyer, q. Note that a low value buyer demands the first good in the hope of paying less than the full surplus for the second. In particular, in equilibrium, such a buyer expects to pay
1+ q 2
for the second good and is therefore willing to pay
1− q 2
for the first, which
is exactly what seller 1 might offer. Seller 1 might, however, also offer a high price of
1 2
to
target a high value buyer. Seller 1’s mixing between these two prices accommodates that of 2’s by keeping his posterior “unbiased” at 12 . As q increases, seller 1 drops his discount price, 1− q 2 ,
to (partially) subsidize a low value buyer for the future holdup, but interestingly he also
drops the frequency,
1− q q ,
of this enticing offer so that his subsidy is not captured by seller 8
2.14 The uninformed prices in part (a) also explain the equilibrium demand in part (c): a low value buyer purchases the first good only at the discount price, upon which she proceeds to purchase the second with certainty, while the opposite is true for a high value buyer. Note that because each seller prices at the buyer’s marginal value, uninformed prices trend upward: the first seller charges no higher and the second seller charges no lower than the stand-alone value. Hence, an informed buyer is more likely to sequence the sellers from high to low value. If this sequencing is strict, namely θ1 ( 12 , 0) = 1, then the informed buyer has low value for the first good only in the case of perfect complements, occurring with probability q2 . Substituting this posterior for the prior q in the uninformed prices yields informed prices in part (b) so long as q >
√1 . 2
That is, an informed buyer begins with the high value
seller if goods are strong complements. For moderate complements,
1 2
< q ≤
√1 , 2
the in-
formed buyer might mix over the sequence although due to rising prices, she is still strictly more likely to begin with the high value seller, θ1 ( 21 , 0) ∈ ( 21 , 1]. Such mixing over the sequence requires equal prices, which can only be at 21 . Inspecting Proposition 1, we can determine the buyer’s payoff and identify the two key effects of being informed: sequencing and pricing. Recall that the first seller offers the discount price to entice a low value buyer, leaving her with no expected surplus. This means that despite a joint purchase, a low value buyer incurs a loss if she receives a high price from the second seller. Such holdup does not apply to a high value buyer because she can opt to purchase only the first good. Corollary 1 records this useful observation about the payoffs. Corollary 1 A low value buyer of the first good (v1 = 0) obtains an expected payoff of 0 while a high value buyer (v1 = 12 ) obtains a positive expected payoff equal to her expected payoff from the first purchase. From Corollary 1 and Proposition 1, the expected payoff of an uninformed buyer is found to be 1−q B ( q ) = (1 − q ) q U
=
1 1−q − 2 2
(1 − q )2 1 if q > , 2 2
where 1 − q is the probability that v1 = 1− q 2 ,
1 2
and
1− q q
(1)
is the probability of the discount price,
by the first seller. For strong complements, the expected payoff of an informed buyer is
14 Indeed,
1− q
with probability q q = 1 − q, a low value buyer acquires both goods but ends up with a loss of illustrating the holdup problem.
9
1− q 2 ,
analogously found by replacing 1 − q in (1) with 1 − q2 – the probability that v1 =
1 2
under
strategic sequencing. For moderate complements, the expected informed payoff is zero since the first seller targets the high value buyer; hence, (1− q2 )2 if 2 I B (q) = 0 if
q> 1 2
√1 2
(2)
√1 . 2
To identify the two effects of being informed, we also compute a counterfactual payoff for the buyer in which she sequences informed but the sellers are “nonstrategic” in that they keep their uninformed prices. Substituting the probability 1 − q2 for 1 − q in the first term of (1), we find the expected informed payoff with nonstrategic sellers: I
B (q) =
(1 − q2 )(1 − q) 1 if q > . 2 2
(3)
I
Evidently, B (q) > BU (q), implying a positive sequencing effect of being informed: given uninformed prices, the buyer strictly benefits from the ability to match a high value good I
with a low price seller. Moreover, B I (q) < B (q) for q >
√1 ; 2
1 2
< q ≤
√1 , 2
I
and B I (q) > B (q) for
so the pricing effect of being informed is negative for moderate complements and
positive for strong complements. As indicated by Corollary 1, the direction of the pricing effect depends on the first seller. Note from Proposition 1 that the first seller offers an expected price of
q 2
to an uninformed buyer while he offers a higher price of
and a lower expected price of
q2 2
1 2
for moderate complements
for strong complements to an informed buyer. Intuitively,
informed sequencing increases the probability that the first seller faces a high value buyer. For moderate complements, this probability is significant enough that the second seller chooses a low price, ruling out the holdup and in turn, inducing aggressive pricing by the first seller. For strong complements, the probability of a high value buyer is less significant and thus the second seller also puts weight on the full – surplus extracting – price of 1, leading the first seller to decrease his average price for a low value buyer. An interesting implication of the pricing effect is that for strong complements, an informed buyer prefers strategic sellers who read into her sequencing to those who do not while for moderate complements, she prefers nonstrategic sellers. From Corollary 1, it is clear that an informed buyer sequences to reduce the risk of holdup by the last seller.15 We therefore predict that an informed buyer is more likely to purchase the 15 This
strategy is consistent with the evidence on land assembly alluded to in the Introduction.
10
bundle than the uninformed. To confirm, we calculate from Proposition 1 that an uninformed buyer purchases the bundle with probability q
1−q + (1 − q)(1 − q) = (1 − q)(2 − q), q
whereas an informed buyer purchases the bundle with certainty for moderate complements and with probability (1 − q2 )(2 − q2 ) for strong complements. Since q2 < q, we have Corollary 2 An informed buyer is strictly more likely to purchase the bundle than an uninformed buyer. Note that both informed and uninformed buyers are less likely to purchase the bundle of stronger complements, i.e., a greater q, due to the increased chance of holdup. Nevertheless, given complementarity, the buyer should be less inclined to purchase a single good. Corollary 3 An informed buyer is strictly more likely to purchase the bundle than a single good. The same is true for an uninformed buyer if and only if q < 34 . Corollary 3 follows because unable to sequence optimally, the uninformed buyer guards against the holdup by acquiring only one unit when the holdup is sufficiently likely. Together with Corollary 2, this result points to the social value of information. The value of information to the buyer, however, depends on the sequencing and pricing effects, as we study next.
4
Information acquisition
Before examining information acquisition when it is unobservable to the sellers, we establish two benchmarks, one in which the buyer can publicly commit to visiting the sellers informed or uninformed, and the other in which a social planner dictates such commitment. Optimal information acquisition. By definition, the buyer’s value of information is the difference between her informed and uninformed payoffs: ∆(q) ≡ B I (q) − BU (q). Using (1) and (2), we have ∆(q) =
(1−q)2 (q2 +2q) 2
2 − (1−2q)
q>
if
√1 2
(4) if
1 2
√1 . 2
Eq.(4) implies that for moderate complements, the buyer is strictly worse off being informed! As discussed above, informed sequencing causes the first seller to set the high price 11
in this case, leaving no surplus to the buyer. Put differently, for moderate complements, the negative pricing effect of being informed dominates the positive sequencing effect. For strong complements, both effects are positive and so is the value of information, which the buyer weighs against the cost of information, c. Proposition 2 If goods are strong complements, q >
√1 , 2
and the information cost is low enough,
c < ∆(q), then the buyer optimally acquires information. If, on the other hand, goods are moderate complements,
1 2
√1 , 2
she optimally stays uninformed.
Hence, the buyer prefers informed sequencing if and only if goods are strong complements and the information cost is low. Otherwise, even with no information cost, the buyer prefers to sequence uninformed. The buyer can credibly remain uninformed by: (1) significantly raising her own cost, perhaps through overloading with multiple tasks (Aghion and Tirole, 1997); (2) delegating her sequencing decision to an uninformed third party; or (3) letting the sellers self-sequence. Note that if the sellers were nonstrategic, the value of information would be positive for all q > 12 . To see this, we subtract (1) from (3): ∆(q) ≡ Interestingly, ∆(q) < ∆(q) for q >
√1 . 2
(1 − q )2 q . 2
(5)
That is, for strong complements, the buyer has a
greater incentive to be informed when the sellers are strategic and read into her sequence, which simply follows from the positive pricing effect identified above. Since informed sequencing increases the probability of a joint sale, the buyer’s optimal information strategy is unlikely to be (socially) efficient, which we demonstrate next. Efficient information acquisition. Suppose that a social planner who maximizes the expected welfare can publicly instruct the buyer whether or not to acquire information. Consider an uninformed buyer. From Proposition 1, the expected welfare defined as the expected total surplus is computed to be 1−q 2q − 1 1 1 U W (q) = q (1) + (1 − q)( ) + (1 − q) q( ) + (1 − q)(1) q q 2 2 1 = (1 − q)(3 + q). 2 Similarly, the expected welfare under an informed buyer is W I (q) = q >
√1 , 2
1 2 (1
− q2 )(4 − q2 ) if
and W I (q) = 1 if q ∈ ( 21 , √1 ] since in the latter case, the bundle is purchased with 2
certainty. Hence, the social value of information is ∆W (q) ≡ W I (q) − W U (q) or 12
∆W ( q ) =
∆(q) +
1− q2 2
q>
if
√1 2
(6)
q2 +2q−1 2
if
1 2
√1 . 2
the sellers believe that with φ∗ , the buyer performs informed sequencing.
13
much on informed sequencing while the opposite holds for strong complements under which the pricing effect is positive. It is intuitive that by restricting her ability to commit, the unobservability of information acquisition cannot make the buyer better off than her optimal strategy. It may, however, strictly increase the welfare by encouraging informed sequencing for moderate complements. As mentioned above, although the buyer would want to sequence the sellers of moderate complements uninformed, this is not credible. She would not sequence them informed either because the value of information, ∆(q), is negative in this region, establishing strict mixing ¯ (q). The unobservability may also lower the welfare: for strong in equilibrium for c < ∆ complements, the buyer acquires information even less frequently than efficient.
5
Extensions and Variations
In this section, we consider several extensions of the model pertaining to the bargaining protocol and information structure.
5.1
Sequential procurement vs. auction
Up to now, we have assumed sequential procurement of goods and services. This is natural if, as with job interviews, the buyer has a capacity or privacy concern to deal with both sellers. Absent such concerns, the buyer could alternatively hold an auction in which she receives simultaneous price offers from the sellers and decides which good(s) to acquire after being informed of all prices and valuations. The obvious advantage of an auction over sequential procurement is that the buyer avoids the holdup problem and will incur no ex post loss. Its potential disadvantage is that having no sequence, both sellers are likely to target the buyer’s extra surplus from complementarity. Therefore, in the auction, the sellers are expected to coordinate prices to avoid exceeding the buyer’s joint valuation, but this makes them less generous in their price discounts. Lemma 2 confirms this conjecture. A = 1 , for all q. For Lemma 2 In the auction, there is a symmetric-price equilibrium, piA = p− 2 h i i √ 1− q 5−1 1 A A = q ≥ 2 , there is also a continuum of asymmetric-price equilibria: pi ∈ 2 , 1 − 2q and p− i
1 − piA . The multiplicity of equilibria is not surprising because the sellers play a simultaneous game of price coordination in the auction. In equilibrium, prices sum to the joint valuation of 14
1, with each being no lower than the discount price,
1− q 2 ,
offered by the leading seller under
uninformed sequencing (see Proposition 1(a)). Note that the buyer efficiently purchases the bundle in the symmetric equilibrium but enjoys no surplus – i.e., B A (q) = 0 whereas in the h i (1− q )2 (1− q ) q asymmetric equilibria, she receives a positive expected payoff, B A (q) ∈ , , as she 2q 2 may realize a high value on the lower price item. To understand the buyer’s choice between sequential procurement and auction, consider uninformed sequencing. This comparison is the most meaningful because the auction is strategically equivalent to uninformed sequencing except that price offers are “nonexploding” – i.e., all purchases are decided after visiting both sellers.17 Using (1), it is evident that the buyer will inefficiently choose sequential procurement if she anticipates symmetric pricing in the auction and Lemma 2 indicates that such an equilibrium always exists. On the other hand, the buyer may also choose an auction if she anticipates asymmetric pricing. Proposition 5 records these observations.
Proposition 5 For all q, there is an equilibrium in which an uninformed buyer chooses sequential √ procurement over an auction. This equilibrium is unique if q ∈ 12 , 52−1 ; otherwise, there is also an equilibrium in which she holds an auction. Hence, the buyer may adopt sequential procurement as assumed in the base model. While the multiplicity of equilibria in the auction prevents a clear prediction of this choice for all q, it is worth noting that the symmetric-price equilibrium maximizes the sellers’ joint payoff and is therefore likely to be their “focal point”. Based on the strategic equivalence alluded to above, an alternative interpretation of Proposition 5 is that the buyer may prefer exploding offers to nonexploding offers in sequential procurement. Again, while the former expose the buyer to holdup, they also compel the first seller to significantly cut price to entice the initial purchase.
5.2
Correlated values
Up to now, we have also assumed that stand-alone values, vi , are independent. Yet, in many applications, they may be (positively) correlated.18 For instance, a developer who is unable to acquire the desired land parcels for a shopping mall may appraise each similarly for a smaller 17 Moreover, in either setting, the buyer reveals no price information interim and eventually learns all her valuations. 18 The argument for negatively correlated goods is symmetric.
15
project. Here we show that correlation reduces the incentive for informed sequencing. To this end, consider the following joint distribution of stand-alone values: Pr(v1 , v2 ) 0 1 2
0 2 q + rq(1 − q) (1 − r ) q (1 − q )
1 2
(1 − r ) q (1 − q ) (1 − q)2 + rq(1 − q)
where r ∈ [0, 1] denotes the correlation coefficient, with r = 0 and 1 referring to the base model and ex post homogenous goods, respectively. The equilibrium characterization with correlation closely mimics Proposition 1 (see Proposition A2). In particular, the expected uninformed payoff in (1) remains intact since, as in the base model, the buyer’s equilibrium payoff depends on the first deal. The expected informed payoff in (2) is, however, slightly modified by replacing the posterior q2 with Pr(0, 0): 2 [1−Pr2(0,0)] if q > q (r ) BC,I (q; r ) = 0 if 12 < q ≤ q(r ) where q(r ) ≥
1 2
uniquely solves Pr(0, 0) =
1 2
such that q0 (r ) < 0, q(0) =
√1 , 2
(7)
and q(1) = 12 . By
subtracting (1) from (7), we obtain the value of information under correlation:
∆ (q; r ) = C
[1−Pr(0,0)]2 −(1−q)2 2
2 − (1−2q)
q > q (r )
if
(8) if
1 2
< q ≤ q (r ).
As expected, ∆C (q; 0) = ∆(q). Moreover, ∆C (q; 1) = 0. This makes sense because when goods are ex post homogeneous, the buyer’s ability to match a high value good with a low price seller under informed sequencing is inconsequential. More generally, informed sequencing becomes less consequential when goods are more correlated and thus less heterogeneous: formally, ∆C (q; r ) is strictly decreasing in r for q > q(r ). It is, however, worth noting that since Pr(0, 0) is increasing in r, q0 (r ) < 0; that is, correlation reduces the incentive to remain uninformed by increasing the likelihood of perfect complements.
5.3
Partial information
In the base model, the buyer can discover both valuations ex ante by paying a fixed cost; that is, information is all-or-nothing. If the marginal cost of information is significant, however, the buyer may choose to learn only one valuation. We argue that the buyer is unlikely to
16
gain from such “partial” information. Suppose that prior to meeting with the sellers, the buyer privately discovers only vi . If she approaches seller i second, then she engenders the uninformed equilibrium described in Proposition 1 and obtains a positive expected payoff for q > 21 . If, instead, the buyer approaches seller i first, she receives an expected payoff of 0 irrespective of vi . For a low value buyer, this follows from Corollary 1. For a high value buyer, this follows because seller i would infer the buyer’s valuation from sequencing and charge a sure price of 12 , leaving no surplus to the buyer. We therefore obtain Proposition 6. Proposition 6 Suppose q >
1 2
and that the buyer is privately informed of vi only. Then, she optimally
sequences seller i second and receives her uninformed payoff in (1). Proposition 6 justifies our focus on all-or-nothing information. Intuitively, the buyer cannot exploit partial information as it leaks through her sequencing; to avoid this, the buyer begins with the seller of the uncertain good, effectively committing to behaving uninformed. This contrasts with a fully informed buyer whose sequencing leaves a significant probability that the first seller has a low value item.
5.4
To identify strategic sequencing as a source of bargaining power for the buyer, we have assumed that sellers make the price offers – i.e., each operates in a seller’s market. We predict that the buyer will value sequencing less if she expects a buyer’s market. To confirm, let mi ∈ {si , b} denote the state of market i, which favors either seller i or the buyer as the pricesetter. We assume that sellers already know their respective market conditions but the buyer needs to find out.19 Specifically, the buyer is assumed to learn m1 and m2 at an interim stage between information acquisition and meeting with the sellers.20 Letting Pr(m1 , m2 ) be the joint probability distribution over the states of the markets, the following proposition shows that the buyer discounts the value of information by the likelihood of facing a seller’s market in each meeting.
19 In the real estate market, the buyer can discover the market condition from the stock of listings or expert opin-
ions while in the labor market, the employer can ascertain it from the initial screening of candidates, anticipating that peer institutions receive similar applications. 20 Though convenient, this timing of events is not crucial. Our conclusion in Proposition 7 would not change if the buyer learned m1 and m2 before her information decision.
17
m
5.5
Uncertain joint value
In the base model, we have also maintained that the buyer’s joint value is commonly known. This fits well applications where the buyer has a large winning project: e.g., a retail chain opening a large enough store that ensures monopolizing a local market; a vaccine company acquiring all the necessary antigens to guarantee an effective vaccine; and a lobbyist seeking bipartisan support that secures the favorable legislation. In other applications, the buyer’s joint value may be uncertain – at least initially. For instance, an academic department may be unsure of the synergy level between potential faculty hires. Here we show that consistent with the base model, the buyer has an incentive to learn her joint value to avoid the future holdup. To distinguish it from the information incentive due to sequencing, suppose that stand-alone values are equal and commonly known, v1 = v2 = v ∈ [0, 12 ]. The joint value, however, is uncertain: V = 1 or V > 1 where Pr{V = V } = α ∈ (0, 1). As in the base model, the buyer can privately discover V at a cost prior to meeting with the sellers or wait until she meets with both (so the second purchase is always informed). Proposition 8 characterizes the value of information in this setting.
21 That is, sequential procurement would essentially turn into a one-market problem where the seller makes the offer to a buyer with a privately known outside option, 0 or 12 .
18
Proposition 8 Consider the setting with an uncertain joint value as described above. In equilibrium, the buyer’s uninformed payoff is B J,U (α) = 0 whereas her informed payoff and thus her value of information is
∆ J (α) = B J,I (α) =
α (V − 1) v 1− v α ( V
if
− 1) if
0
if
α≤ v v +V −1
v v +V −1
<α≤
α>
1− v V −v
1− v . V −v
An uninformed buyer receives no expected surplus because the first seller offers the highest price acceptable in expectation. This means that an uninformed buyer may realize a loss after the second purchase if her joint value turns out to be low. To minimize such holdup, the buyer therefore has an incentive to approach the sellers informed. An informed purchase from the first seller, however, leads the second seller to be more optimistic about a high joint value and raise price, fully extracting the buyer’s surplus when a high joint value is sufficiently likely, i.e., α >
1− v . V −v
Similar to the base model, Proposition 8 indicates that a negative
pricing effect may completely outweigh the benefit of informed purchases. Together, ∆ J (α) and ∆(q) imply that the buyer is likely to discover her stand-alone values for strong complements and her joint value for moderate complements.
6
Substitutes
Sequential procurement and thus the issues of information acquisition and sequencing can also be pertinent to substitutes – e.g., parcels at rival locations and job candidates with comparable skills. We, however, argue that with substitutes, sequential procurement is undesirable for the buyer as it forecloses competition between the sellers; instead, the buyer is likely to hold an auction with simultaneous price offers. To make the point, let the buyer’s joint value be 1 (as in the base model) but her stand-alone values be independently distributed such that Pr{vi = 1} = qu and Pr{vi =
1 2}
= 1 − qu . Clearly, with probability q2u , goods are perfect
substitutes whereas with probability (1 − qu )2 , they are independent. We assume qu >
1 2
so
that perfect substitutes are more likely.22 Proposition 9 Consider substitute goods with qu > 12 . Then, an uninformed buyer strictly prefers auction to sequential procurement. 22 Again, the comparison is for an uninformed buyer because as mentioned in Section 5.1, the auction is strategically equivalent to uninformed sequencing except that price offers are nonexploding.
19
Proposition 9 is easily understood for (almost) perfect substitutes, qu ≈ 1. Unsurprisingly, the auction engenders the most competitive prices of 0 and in turn, the highest expected payoff of 1 for the buyer. In contrast, sequential procurement results in the monopoly prices of 1 and yields the lowest payoff of 0. The latter follows because with no previous purchase, the last seller sets his monopoly price and anticipating this, so does the first seller, leaving no surplus to the buyer. The buyer continues to receive monopoly prices under sequential procurement for imperfect substitutes, qu > 12 , but due to competition, lower prices are likely in the auction. In particular, the proof of Proposition 9 establishes that there is no pure strategy equilibrium in the auction: the sellers trade off pricing for perfect substitutes and pricing for independent units.
7
Conclusion
In this paper, we have explored the optimal sequencing of complementary negotiations with privately known values. Our analysis has produced three main observations. First, an informed buyer begins with the high value seller to mitigate the future holdup. Second, because of the sellers’ pricing response, the buyer may be strictly worse off with informed sequencing; that is, ignorance may be bliss. And third, the buyer underinvests in information from a social stand point: informed sequencing increases the likelihood of an efficient (joint) purchase but also the risk of holdup. As mentioned in the Introduction, the empirical evidence on land assembly corroborates our first observation in that real estate developers are estimated to assemble land parcels with a flexible design in mind to dissuade possible holdouts. On the other hand, the evidence on labor market supports our second observation in that job candidates are often advised by career consultants against reading into the interview sequence. Nonetheless, job candidates’ interest in the sequence is consistent with their potential uncertainty about who actually schedules interviews – the employer or (uninformed) staff member.
20
Appendix A As in the text, we re-label the sellers so that the sequence is s1 → s2 unless stated otherwise. For future reference, Proposition A1 characterizes the equilibrium with the following information structure: the buyer privately knows z ∈ { I, U } but the sellers commonly believe that Pr{z = I } = φ ∈ [0, 1]. Conditional on this information structure, let q1 (φ) = Pr{v1 = 0|φ} be the posterior belief that s1 is of low value. 1 2
Proposition A1. In equilibrium, p2 (h = 0) = (a) if q1 (φ) < 21 , then p1 = p2 (h = 1) = (b) if q1 (φ) = 21 , then p1 =
β 2
and
1 2
and the buyer purchases the bundle with certainty; 1 β 2 with prob. , and p2 (h = 1) = 1 with prob. 1 − β
where β ≥ 12 . The buyer purchases from s1 with certainty and s2 only if v1 = 0 or p2 (h = 1) = 21 ; (c) if q1 (φ) > 12 , then
p1 =
1− q1 ( φ ) 2
1 2
with prob.
1− q1 ( φ ) q1 ( φ )
and p2 (h = 1) = with prob.
2q1 (φ)−1 q1 ( φ )
1 2
1 with prob.
with prob. 1 − q1 (φ) . q1 ( φ )
Moreover, a buyer with v1 = 0 accepts only low p1 but all p2 (h = 1) whereas a buyer with v1 =
1 2
accepts all p1 but only the low p2 (h = 1). Proof. Consider pricing by s2 . Clearly p2 (h = 0) =
1 2
since s2 realizes a positive payoff
only if v2 = 12 . Let h = 1. Then a buyer with v1 = 0 accepts any offer p2 (h = 1) ≤ 1 whereas a buyer with v1 =
1 2
accepts only p2 (h = 1) ≤ 12 . Thus, s2 ’s optimal price is
p2 ( h = 1) =
1 2
1 if qb1 (φ, 1) ≥ 12 ,
if
qb1 (φ, 1) ≤
1 2
(A-1)
where qb1 (φ, h) = Pr{v1 = 0|φ, h} is the posterior conditional on the buyer’s information and purchase history. Anticipating p2 (h = 1), a buyer with v1 is willing to pay s1 up to p1 (v1 ) such that max{1 − p1 (v1 ) − p2 (h = 1), v1 − p1 (v1 )} = 0, 21
or simplifying, p1 (v1 ) = max{1 − p2 (h = 1), v1 }. Next we show that qb1 (φ, 1) ≤
1 2
(A-2)
in equilibrium. Suppose, to the contrary, that qb1 (φ, 1) > 21 .
Then p2 (h = 1) = 1, p1 (v1 = 0) = 0, and p1 (v1 = 12 ) = 12 . But this would imply p1 =
1 2
and
in turn qb1 (φ, 1) = 0 – a contradiction. We exhaust two possibilities for qb1 (φ, 1). qb1 (φ, 1) <
1 2
: Then p2 (h = 1) =
1 2
from (A-1), and p1 (v1 = 0) = p1 (v1 = 21 ) =
2). This implies qb1 (φ, h) = q1 (φ) and thus q1 (φ) <
1 2,
1 2
from (A-
which reveals that the buyer purchases
the bundle with certainty, proving part (a). qb1 (φ, 1) =
1 2
: By (A-1), s2 is indifferent between the prices
with probability β. Then, by (A-2), p1 (v1 = 12 ) = the prices 12 and accepts
β 2
β 2
1 2
1 2
and 1. Suppose s2 offers
1 2
β
and p1 (v1 = 0) = 2 . Let s1 mix between
by offering the latter with probability γ ∈ [0, 1]. Evidently, the buyer always
whereas only the buyer with v1 =
1 2
accepts 12 . Using Bayes’ rule, we therefore have
1− q1 ( φ ) . For q1 (φ) = 12 , γ = 1 q1 ( φ ) β β or p1 = 2 . By the buyer’s optimal purchasing decision, this means 2 (1) ≥ 12 (1 − q1 (φ)) or equivalently β ≥ 12 , resulting in the equilibrium multiplicity in part (b). Finally, for q1 (φ) > 12 , β 1− q1 ( φ ) γ ∈ (0, 1). Such strict mixing by s1 requires 2 = or β = 1 − q1 (φ), proving part (c). 2 1 Proof of Lemma 1. Suppose q ≤ 2 . For z = U, φ = 0 and q1 (0) = q. For z = I or φ = 1, it must be that q1 (1) ≤ 21 ; otherwise, if q1 (1) > 21 , equilibrium prices in Proposition A1 would imply an informed sequence strictly from high to low value – i.e., θ1 ( 12 , 0) = 1, and in turn, q1 (1) = q2 < 12 – a contradiction. Given that q1 (0) ≤ 12 and q1 (1) ≤ 12 , Proposition A1 further reveals that ( p1z , p2z (h)) = ( 21 , 21 ) for z = I, U and h = 0, 1, inducing a joint purchase, where the sellers’ indifference at q1 (φ) = 12 is broken in favor of efficient pricing. Proof of Proposition 1. Suppose q > 12 . For z = U, parts (a) and (c) are immediate from Proposition A1 since q1 (0) = q. Next, consider z = I. If q > √1 , the proof of Lemma 1 has 2 established that θ1 ( 12 , 0) = 1 and q1 (1) = q2 > 12 . Therefore, q1 (1) ≤ 12 if q ∈ ( 12 , √1 ], where 2 sellers break indifference in favor of efficient pricing at q1 (1) = 21 . This implies θ1 ( 21 , 0) > 12
qb1 (φ, 1) =
γq1 (φ) , γq1 (φ)+1−q1 (φ)
which, given qb1 (φ, 1) = 21 , implies γ =
given that by Bayesian updating, q1 (1) =
q2 21 + q(1 − q)[1 − θ1 ( 12 , 0)] 1 2
1 = q2 + 2q(1 − q)[1 − θ1 ( , 0)]. 2 Applying Proposition A1, we obtain parts (b) and (c) for z = I. 22
(A-3)
Proof of Corollary 1. Obvious from Proposition 1. Proof of Corollary 2. Directly follows from the probability of a joint purchase found in the text. Proof of Corollary 3. From Proposition 1, an informed buyer obtains the bundle of moderate complements with probability 1. She obtains a single unit of strong complements if and only if she has at least one high value and receives a high second price, whose probability is
(1 − q2 )q2 and strictly less than (1 − q2 )(2 − q2 ). The probability of a single purchase by an uninformed buyer is
(1 − q ) q + q
2q − 1 (1 − q) = (1 − q)(3q − 1), q
where the first term is the probability that v1 = is the probability of rejecting pU 1 =
1 2
1 2
and pU 2 ( h = 1) = 1, while the second term
1 due to v1 = 0 and accepting pU 2 ( h = 0) due to v2 = 2 .
Since the probability of a joint purchase is (1 − q)(2 − q), the buyer is more likely to purchase both if and only if q < 34 . Proof of Proposition 2. Directly follows from (4). Proof of Proposition 3. Directly follows from (4) and (6). Proof of Proposition 4. Consider first q >
√1 . 2
Then θ1 ( 12 , 0) = 1 and q1 (1) = q2 (by
(A-3)), which imply q1 (φ) = φq1 (1) + (1 − φ)q ≥ φq2 + (1 − φ)q > 21 . Moreover, the value of ˆ (φ) = q(1 − q) 1−q1 (φ) . Comparing with (4), information under unobservable acquisition is ∆ 2
ˆ (φ) ≤ ∆(q) for all φ. To determine when φ∗ < 1, note that for c < ∆(q), it is optimal for ∆ ˆ (1) = the buyer to acquire information. With unobservability, however, φ∗ = 1 requires c ≤ ∆ 1− q2 2 = 1 consider 2 < q
q (1 − q )
(1 + q)∆(q). Therefore, φ∗ < 1 for (1 + q)∆(q) < c < ∆(q), as claimed. Next, ≤ √12 . For φ∗ = 0, q1 (0) = q and ∆ˆ (0) = q(1 − q) 1−2 q = ∆(q). Hence, φ∗ > 0
for c < ∆(q), as desired.
Proof of Lemma 2. In an auction, the sellers play a simultaneous-move pricing game and thus the equilibrium occurs at the intersection of their best responses. Consider seller i’s best response Pi ( p−i ) to price p−i by the other seller. Note that if p−i ≤ generates a sale for si only if v−i = 0, while pi = payoffs, (1 − p−i )q and if 1 −
1 2q
1 2,
1 2
1 2,
then pi = 1 − p−i
guarantees a sale. Comparing si ’s resulting
it follows that Pi ( p−i ) = 1 − p−i if p−i ≤ 1 −
1 2q ,
and Pi ( p−i ) =
1 2
≤ p−i ≤ 21 . If, on the other hand, p−i > 12 , then since v−i ≤ 12 , seller s−i realizes a
sale only if the buyer acquires the bundle. Given this, the price pi = 1 − p−i ensures a sale for si whereas pi =
1 2
is accepted only if vi = 21 , leading to the respective payoffs: 1 − p−i and
(1 − q) 12 . From here, Pi ( p−i ) = 1 − p−i if
1 2
< p −i ≤ 23
1+ q 2 ,
and Pi ( p−i ) =
1 2
if p−i ≥
1+ q 2 .
To
sum up,
Pi ( p−i ) =
1 1 − p−i if 0 ≤ p−i ≤ 1 − 2q 1 1 if 1 − 2q ≤ p−i ≤ 12 2 1 2
1 − p−i if 1 if 2
≤ p −i ≤ p −i ≥
(A-4)
1+ q 2
1+ q 2 .
A = 1. In equilibrium, Pi ( P−i ( piA )) = piA for all i, which, given (A-4), implies that piA + p− i A = Clearly, piA = p− i
1 2
satisfies this condition for all q. Moreover, the only asymmetric prices h i 1− q 1 1 1+ q A = 1 − pA ∈ that satisfy this condition are: piA ∈ [ 2 , 1 − 2q ] and p− , i i 2q 2 . The interval √
for piA is nonempty if and only if q ≥
5−1 2 .
A = Proof of Proposition 5. By Lemma 2, piA = p− i
1 2
is an equilibrium for all q when the
buyer holds an auction, resulting in the expected payoff B A = 0. Under sequential procurement with an uninformed buyer, BU = 0 for q ≤
1 2
(by Lemma 1) and BU =
(1− q )2 2
for q >
1 2
(by (1)). Therefore, there is an equilibrium, in which the buyer chooses sequential procurement with an off-equilibrium belief that symmetric pricing would occur under the auction. √ For q ∈ 21 , 52−1 , B A = 0 is the unique equilibrium payoff and BU > B A , indicating a √
unique equilibrium with sequential procurement. For q ≥ 52−1 , given the equilibrium prich i 2 (1− q )2 (1− q ) q ing in Lemma 2, B A ∈ , ∪ {0}. Note that BU < (1−2qq) , implying that in this 2q 2 region there is also an equilibrium in which the buyer chooses to hold an auction and the sellers charge asymmetric prices piA ∈ [
1− q 1 2 , 1 − 2q ]
A = 1 − pA. and p− i i
Proposition A2. (Informed prices with correlation) As defined in Section 5.2, let q(r ) be the unique solution to Pr(0, 0) = 1) =
p1I
1 2
=
1 2,
where Pr(0, 0) = q2 + rq(1 − q). In equilibrium, p1I = p2I (h =
for q ≤ q(r ) with θ1 ( 21 , 0) >
1−Pr(0,0) 2
with prob.
1 2
with prob.
1 2
for q > 12 ; and
1−Pr(0,0) Pr(0,0)
and 2 Pr(0,0)−1 Pr(0,0)
p2I (h
= 1) =
1 2
1 with prob.
with prob. 1 − Pr(0, 0) Pr(0, 0)
and θ1 ( 12 , 0) = 1 for q > q(r ). Proof. Using the joint distribution Pr(v1 , v2 ) in Section 5.2, the posterior belief in (A-3)
24
generalizes to: q1 (1) =
Pr(0, 0) × 21 + Pr( 21 , 0) 1 − θ1 ( 12 , 0) 1 2
1 1 = Pr(0, 0) + 2 Pr( , 0) 1 − θ1 ( , 0) . 2 2 By Proposition A1, if q1 (1) > 12 , then θ1 ( 12 , 0) = 1 and q1 (1) = Pr(0, 0). Therefore q1 (1) > 1 2 , or equivalently q > q (r ). On the other hand, for q ≤ q (r ), q1 (1) ≤ 21 , which requires θ1 ( 12 , 0) > 12 . Equilibrium prices follow from Proposition A1. Proof of Proposition 6. Suppose q > 12 and that the buyer is privately informed of vi only. If si is second in the sequence, the buyer receives the uninformed payoff in (1), BU (q) > 0, 1 2
if and only if Pr(0, 0) >
because she is uninformed of v−i and the second seller’s pricing depends only on the prior q in this case. Suppose, instead, that si is first and let qe1 = Pr{vi = 0|si is first}. If vi = 0, the buyer receives an expected payoff of 0 because, by Proposition A1, for qe1 ≤ 12 , each seller charges
1 2
whereas for qe1 >
1 2,
si sets his low price to leave no expected surplus. Hence, a
buyer with vi = 0 strictly prefers to sequence si second and obtain BU (q) > 0. This implies qe1 = 0 and by Proposition A1, an expected payoff of 0 for the buyer when approaching si first. Therefore, in equilibrium, si is sequenced second, yielding the buyer her uninformed payoff in (1). Proof of Proposition 7. Let m = (m1 , m2 ). By definition, the buyer’s expected value of information is m
2
∆ (q) = Pr(b, b)∆(b,b) (q) + ∑ Pr(si , b)∆(si ,b) (q) + Pr(s1 , s2 )∆(s1 ,s2 ) (q). i =1
If m1 = m2 = b, the buyer optimally offers 0 to each seller, implying B I (q) = BU (q) = 1 and in turn, ∆(b,b) (q) = 0. If, on the other hand, mi = si for i = 1, 2, the setting reduces to our base model, implying ∆(s1 ,s2 ) (q) = ∆(q) where ∆(q) is as stated in (4). It therefore remains to prove that if mi = si and m−i = b, then ∆(si ,b) (q) = 0. Suppose m = (si , b). We consider uninformed and informed buyers in turn. Uninformed buyer: If the sequence is s−i → si , the buyer always purchases from s−i (at price 0) and thus the optimal price by si is given by (A-1) where φ ( = 0 and qb1 (0, 1) = q. 1 i f q ≤ 21 2 This means that the buyer’s uninformed payoff is: BU (s−i → si ) = . If, 1− q i f q > 21 2 however, the sequence is si → s−i , the buyer’s expected payoff from rejecting si ’s offer is
25
1− q 2 ,
which is simply the expected payoff from acquiring good i only. Therefore, the high-
est acceptable price by si in the first period satisfies max{1 − p1 , v−i − p1 } = ing p1 =
1+ q 2
and an expected payoff:
BU ( s
i
1− q 2 .
→ s −i ) =
1− q 2 ,
reveal-
Comparing the two payoffs,
BU = BU ( s −i → s i ). Informed buyer: If the sequence is s−i → si , the optimal price by si is given by (A-1) where φ = 1 and qb1 (1, 1) = q1 (1) since the buyer always purchases from s−i . If the sequence is si → s−i , the highest price acceptable to the buyer in the first meeting satisfies max{1 − p1 , v−i − p1 } = vi . Therefore, the optimal price by si is 1 2 i f q2 (1) ≤ p1 = 1 i f q2 (1) ≥
1 2
(A-5)
1 2
where q2 (1) = Pr{v−i = 0|s−i is second}. The buyer with v−i = 0 accepts p1 for sure whereas a buyer with v−i = 1 accepts only the low p1 . Let θbk (v−i ) = Pr{s−i is kth |v−i } and qk (1) = 2
Pr{v−i = 0|s−i is kth}. Then, by Bayes’ rule, q k (1) =
qθbk (0) qθbk (0) + (1 − q)θbk ( 12 )
.
(A-6)
We show that there is no equilibrium in which B I 6= BU . If, in equilibrium, θbk (0) = θbk ( 12 ) = 1 for some k = 1, 2, then qk (1) = q and, by (A-1) and (A-5), B I = BU . Suppose θbk (0) ∈ (0, 1). Then qk (1) is uniquely pinned down for k = 1, 2 using (A-6). We consider three cases for q k (1). 1 2
for k = 1, 2 : Since θb−k (v−i ) = 1 − θbk (v−i ), by (A-6), such an equilibrium belief requires 2q − 1 ≤ qθbk (0) − (1 − q)θbk ( 1 ) ≤ 0 and in turn, q ≤ 1 . From (A-1) and
• q k (1) ≤
2
2
(A-5), we therefore have that the informed and uninformed prices by si is 21 , resulting in B I = BU . • q k (1) >
1 2
for k = 1, 2 : By (A-6), this requires q > 21 , which, by (A-1) and (A-5), induces
the informed and uninformed prices of 1 by si . Therefore, B I = BU . • q k (1) ≤
1 2
< q−k (1) : By (A-1) and (A-5), approaching s−i in kth place results in a price
1 2
by si , while approaching s−i in −kth place results in a price of 1 by si . Therefore, a buyer with v−i = 0 has a strict preference to approach s−i kth, i.e. θbk (0) = 1. By of
(A-6), however, this implies that q−k (1) = 0 < qk (1), contradicting the existence of an equilibrium with qk (1) ≤
1 2
< q − k (1). 26
Consequently, there is no equilibrium with B I 6= BU . An equilibrium with B I = BU obtains by setting θb1 (0) = θb1 ( 21 ) ∈ (0, 1), resulting in qk (1) = q for k = 1, 2, which, by (A-1) and (A-5), yields identical informed and uninformed pricing by si . Proof of Proposition 8. Suppose that v1 = v2 = v ∈ [0, 12 ] and the joint value is V = 1 or V > 1 where Pr{V = V } = α ∈ (0, 1). Let αˆ (h) = Pr(V = V |h). Then, the optimal price by the second seller upon observing a prior purchase is
p2 ( h = 1) =
1−v
if αˆ (1) ≤
1− v V −v
V − v if αˆ (1) ≥
1− v V −v
.
(A-7)
Without a prior purchase, the second seller trivially offers p2z (h = 0) = v. The pricing by the first seller depends on whether the buyer is informed or uninformed. Uninformed buyer: Let p1 be the first seller’s maximum price acceptable to the buyer. Denoting by E[.] the usual expectation operator, p1 satisfies: max { E[V ] − p1 − E [ p2 (h = 1)] , v − p1 } = 0, or p1 = max{ E[V ] − E[ p2 (h = 1)], v}. ˆ (1) = α. Therefore, Since any higher price is rejected for sure, pU 1 = p1 and by Bayes’ rule, α 1− v U U for α ≤ V −1 , p1 = α V − 1 + v and p2 (h = 1) = 1 − v while for α > V1−−v1 , pU 1 = v and J,U ( v ) = 0. pU 2 ( h = 1) = V − v. The resulting expected payoff for the buyer is B
Informed buyer: In this case, p1 satisfies p1 = max{V − E[ p2 (h = 1)], v}. We consider three possibilities for αˆ (1). • αˆ (1) <
1− v V −v
: Then, p2 (h = 1) = 1 − v by (A-7), implying that p1L = v is accepted
for sure, whereas p1H = (V − 1) + v is accepted only if V = V. Therefore, for α ≤ v 1− v < , the first seller optimally sets p1 = v (breaking the indifference at α = v +V −1 V −v v v +V −1
in favor of efficiency), which reveals αˆ (1) = α. As a result, for α ≤
v , v +V −1
the
price pair p1I = v and p2I (h = 1) = 1 − v constitute an equilibrium, resulting in the payoff: B J,I (α) = α(V − 1). For α ∈ v+Vv −1 , V1−−vv , the first seller sets p1 = (V − 1) + v, which implies αˆ (1) = 1 and a profitable deviation for the second seller to p2 (h = 1) = V − v. Hence, αˆ (1) < • αˆ (1) =
1− v V −v
1− v V −v
only if α ≤
v v +V −1
resulting in ∆ J (α) = B J,I (α).
: Then, the second seller is indifferent between V − v and 1 − v. Suppose
that he offers 1 − v with probability σ. Then, E[ p2 (h = 1)] = V − v − σ(V − 1), implying 27
that p1L = v is accepted for sure by the buyer while p1H = v + σ(V − 1) is accepted only if V = V. The first seller is indifferent between p1L and p1H if σ = first seller’s mixing β = Pr( p1 = v) = αˆ (1) =
α β+(1− β)α
1− v . V −v
α≤
=
1− v . V −v
Then,
p1H
α (V −1) (1−α)(1−v)
(1− α ) v , α (V −1)
in which case the
≤ 1 engenders an equilibrium belief
= αv . Note that σ ≤ 1 for α ≥
v v +V −1
and β ≤ 1 for
Therefore, the price pair
1 − v with prob. σ v with prob. β I and p ( h = 1 ) = v 2 with prob. 1 − β V − v with prob. 1 − σ α i is an equilibrium for α ∈ v+Vv −1 , V1−−vv . In such an equilibrium, ∆ J (α) = B J,I (v) = p1I =
v 1− v α ( V
− 1). Note that for v = 0, σ = 0 and in turn, p2I (h = 1) = V. Then, p1 = 0.
Using the efficient tie-breaking rule, the first seller offers p1I = 0. Let η (V ) denote the probability that the buyer accepts the first offer given V. Then, by Bayes’ rule, αˆ (1) = η (V ) α . Since efficiency is maximized for η (V ) = 1, αˆ (1) = V1 , and η (1) η (V )α+η (1)(1−α) α (V −1) . Therefore, for v = 0, the price pair p1I = 0 and p2I (h = 1) = V is supported (1− α ) α (V −1) η (1) = (1−α)(1−v) and αˆ (1) = V1−−vv . The buyer’s payoff is B J,I (v = 0) = 0 = ∆ J (α).
• αˆ (1) >
1− v V −v
= by
: Then, p2 (h = 1) = V − v and p1I = p1 = v. The first price is always
accepted by the buyer, implying that αˆ (1) = α >
1− v V −v
and B J,I = 0 = ∆ J (α).
Proof of Proposition 9. Let qu > 12 . Consider sequential procurement with uninformed buyer. If s2 observes no prior purchase, he offers p2 (h = 0) = 1 since it is accepted with probability qu , resulting in a payoff of qu , whereas the alternative price of tainty, resulting in a payoff of
1 2.
1 2
is accepted with cer-
If s2 observes a prior purchase, he offers p2 (h = 1) =
the buyer’s marginal value for his good is
1 2
1 2
since
or 0. Anticipating such pricing, the highest price,
p1 , acceptable to the buyer in the first meeting satisfies: max {1 − p2 (h = 1) − p1 , v1 − p1 } ≥ 0, or simplifying p1 ≤ max {1 − p2 (h = 1), v1 } . This implies p1 = 1 since p1 = 1 is accepted with probability qu and p1 =
1 2
is accepted for
sure. Given the equilibrium prices, sequential procurement yields a payoff of 0 to the buyer. To prove that the auction yields a positive payoff, it suffices to show that in equilibrium, the sellers choose prices lower than 1 with a positive probability. The following two claims make this point. Claim 1 In the auction, there is no pure strategy equilibrium. 28
Proof of Claim 1. As in the standard Bertrand competition, p1 = p2 = p > 0 cannot arise in equilibrium because with probability q2u , goods are perfect substitutes and a slightly lower price would guarantee a sale in this realization. Without loss of generality, suppose p1 < p2 . If 21 < p1 < p2 , then s1 receives an expected profit π1 = qu (1 − qu ) + q2u p1 , p2 + p1 2 .
implying a profitable deviation to p˜ 1 = p1 < p2 ≤
1 2,
The same profitable deviation also exists if
because in this case, p1 is accepted unless v2 = 1 and v1 =
π1 = [1 − qu (1 − qu )] p1 . Finally, if p1 ≤
( π1 , π2 ) =
1 2
1 2,
resulting in
< p2 , the sellers’ expected profits are if p1 < p2 +
1 2
([1 − (1 − σ1 )qu (1 − qu )] p1 , qu (1 − qu )(1 − σ1 ) p2 ) if p1 = p2 +
1 2
( p1 , 0)
([1 − qu (1 − qu )] p1 , qu (1 − qu ) p2 )
if p1 > p2 +
1 2
where σ1 ∈ [0, 1] is an arbitrary tie-breaking rule when the buyer is indifferent. For p1 < p2 + 12 , s2 clearly has a strict incentive to lower his price. The same is true for p1 = p2 + 12 , in which case the buyer is indifferent. For p1 > p2 + 12 , s2 would deviate to p˜ 2 =
p2 + p1 − 12 2
. In
sum, there is no pure strategy equilibrium. Claim 2 In the auction, the following c.d.f. constitutes a symmetric mixed strategy equilibrium: 1 − qu 1 1 − qu 1 F ( p ) = 2 1 − q u (1 − q u ) − for p ∈ , . qu 2p 2(1 − qu (1 − qu )) 2 Proof of Claim 2. Consider a symmetric mixed strategy equilibrium with a continuous support p < p ≤
1 2
and no mass points. Then,
π ( p) = [ F ( p)(1 − qu ) + (1 − F ( p))(1 − qu (1 − qu ))] p = π, where π is the indifference profit across p ∈ [ p, p]. Note that π ( p) = (1 − qu ) p is increasing in p, implying a profitable deviation to p ∈ ( p, 12 ]. Therefore, p = 12 . Re-writing, 1 π F ( p ) = 2 1 − q u (1 − q u ) − . qu p Since F ( 12 ) = 1, π = Thus, F ( p) =
1− q u 2 .
Given this and the fact that F ( p) = 0, we find that p =
1− q u . 2(1−qu (1−qu ))
1 1 − qu 1 − qu 1 , 1 − q ( 1 − q ) − for p ∈ , u u q2u 2p 2(1 − qu (1 − qu )) 2
29
h i as claimed. It remains to show that there is no unilateral deviation incentive to p ∈ / p, 12 . Without loss of generality, consider a deviation by s1 . Clearly, p1 < p is not profitable, because π ( p1 ) = (1 − qu (1 − qu )) p1 < (1 − qu (1 − qu )) p = π ( p). Next consider a deviation to p1 > 12 . Since p1 > 1 is rejected with probability 1, we restrict attention to p1 ∈ ( 12 , 1] . In this case, s1 realizes a sale only if v1 = 1, v2 = 21 , and 1 − p1 >
1 2
− p2 , or equivalently p2 > p1 − 12 . We
exhaust two cases: • p1 −
1 2
≤ p : Then, π ( p1 ) = qu (1 − qu ) p1 . Since this deviation profit is increasing in p1 ,
the maximum deviation profit in this region is 1 1 − qu 1 1 − qu < + = π. π ( p + ) = q u (1 − q u ) 2 2 2(1 − qu (1 − qu )) 2 Therefore, there is no incentive to deviate to p1 ∈ ( 12 , 12 + p]. •
1 2
+ p < p1 ≤ 1 : Then, s1 ’s probability of a sale is qu (1 − qu ) Pr( p2 > p1 − 12 ) and his
deviation profit is
"
1 − qu 1 π ( p1 ) = qu (1 − qu ) 1 − 2 1 − qu + q2u − qu 2( p1 − 12 ) # " 1 (1 − q u )2 = − 1 p1 . qu 2( p˜ i − 21 ) Simple algebra shows that π ( p1 ) <
1− q u 2
!# p1
= π.
Together Claims 1 and 2 prove Proposition 9.
Appendix B Here, we extend our analysis to a more general Bernoulli distribution with valuations vi ∈
{v L , v H } where 0 ≤ v L < v H ≤
1 2
and Pr {vi = v L } = q ∈ (0, 1). The main difference from
the special case in the text (v L = 0 and v H =
1 2)
is that with v L > 0, the second seller may
not always charge the high price v H upon observing no purchase from the first seller – i.e. h = 0. In particular, by charging a low price of v L > 0, the second seller now leaves a positive surplus to the buyer who did not acquire the first object. As in the base model, let z = I, U refer to informed and uninformed sequencing, and
( p1z ,
p2z (h)) be the corresponding pair of prices. Analogous to the base model, for q ≤ 30
1− v H 1−v L , the
value of information is 0, since p1z = p2z (h = 0) = v H and p2z (h = 1) = 1 − v H in equilibrium. Thus, our analysis here focuses on q >
1− v H 1− v L .
Moreover, for z = I, similar to the base model,
we restrict attention to symmetric equilibria that satisfy the Intuitive Criterion. The following proposition characterizes equilibrium for the intermediate values of q and shows that the value of information is negative. nq vH 1− v H Proposition B1. Let q ∈ 11− , min −v L 1− v L , 1 −
vL vH
o
. In equilibrium, pU 2 ( h = 0) =
p2I (h = 0) = v H . Moreover, for (a) an uninformed buyer:
pU 1 =
with prob. 1 −
vH
(1 − q ) v H with prob. and pU 2 ( h = 1) =
1 − v H with prob.
1 − vL
1− q 1− v H q v H −v L
1− q 1− v H q v H −v L v H (1−q)−v L v H −v L
with prob. 1 −
v H (1−q)−v L ; v H −v L
(b) an informed buyer: p1I = v H and p2I (h = 1) = 1 − v H . (c) Demand: An informed buyer accepts both sellers’ offers, while an uninformed buyer with U v1 = v L accepts only the low pU 1 but all p2 ( h = 1) whereas an uninformed buyer with v1 = v H z accepts all pU 1 but only the low p2 ( h = 1).
Proof. Let qb1 (z, 1) = Pr {v1 = 0|h = 1} and qb2 (z, 0) = Pr {v2 = 0|h = 0} denote the sellers’ posterior beliefs given the buyer’s information and purchase history. The optimal pricing by s2 is p2z (h = 1) =
1 − v H if
qb1 (z , 1) ≤
1− v H 1− v L
1−v L
qb1 (z, 1) ≥
1− v H 1− v L
if
since 1 − v H is accepted for sure and 1 − v L only if v1 = v L ; and p2z (h = 0) =
v H if
qb2 (z , 0) ≤ 1 −
vL vH
vL
qb2 (z, 0) ≥ 1 −
vL vH
if
since v L is accepted for sure and v H only if v2 = v H .
31
For z = U, we have that qb2 (z , 0) = q, since the buyer is uninformed about v2 when making a purchasing decision about good 1. Therefore, for q < 1 −
vL vH ,
pU 2 ( h = 0) = v H .
Then, the equilibrium derivation under z = U is analogous to the proof of Proposition 1 and thus omitted here. Next, consider z = I. Clearly, p1 = v H is a best response to p2 (h = 1) = 1 − v H . Given this pricing, the buyer accepts both offers with probability 1. Therefore, upon observing h = 1, vH s2 has no incentives to deviate as long as qb1 (1, 1) = q2 + 2q(1 − q)θ1 (v L , v H ) ≤ 11− −v L . Since q 1− v L the buyer is indifferent in the order, θ1 (v L , v H ) = 0 and q < 1−v H ensure that s2 has no
incentive to deviate. Finally, p2 (h = 0) = v H is supported by an off-equilibrium belief that qb2 (1, 0) ≤ 1 −
vL vH .
This belief passes the Intuitive Criterion since the buyer’s equilibrium
payoff is 0, while rejecting the first offer would result in a payoff of at least 0 for the buyer under the most favorable beliefs regarding v2 (corresponding to p2 (h = 0) = v L ). Thus, rejecting the first offer is not an equilibrium dominated for any realization of v2 . Note that for v L = 0 and v H = 12 , the pricing in Proposition B1 coincides with Proposition 1. Moreover, it is readily verified that the value of information is
(1 − v H ) v H < 0, vH − vL which, given a payoff of 0 for the informed buyer, is simply the negative of the buyer’s unin nq oi 1− v H vH vL formed payoff. Therefore, for moderate complements, i.e., q ∈ 11− , min , 1 − , −v L 1− v L vH ∆(q) = −(1 − q)2
it is optimal for the buyer to stay uninformed, extending Proposition 2. Analogous to the base model, it can also be shown that the buyer’s optimal strategy to remain uninformed is not credible if it is unobservable to the sellers. In particular, if the cost is not too high, the buyer would acquire information with some positive probability in equilibrium, extending Proposition 4.
References [1] Ausubel, L. M., Cramton, P., & Deneckere, R. J. (2002). Bargaining with incomplete information. Handbook of Game Theory with Economic Applications, 3, 1897-1945. [2] Aghion, P., and J. Tirole. (1997) “Formal and real authority in organizations.” Journal of Political Economy, 1-29.
32
[3] Brooks, L., and B. Lutz (2016). “From today’s city to tomorrow’s city: An empirical investigation of urban land assembly.” American Economic Journal: Economic Policy, 8(3), 69-105. [4] Cai, H. (2000). “Delay in multilateral bargaining under complete information.” Journal of Economic Theory, 93, 260-276. [5] Carrillo, J. and T. Mariotti (2000). “Strategic Ignorance as a Self-Disciplining Device”, Review of Economic Studies, 66, 529–544. [6] Cremer, J. (1995). “Arm’s Length Relationships.” Quarterly Journal of Economics, 110, 27595. [7] Cunningham, C. (2013) “Estimating the Holdout Problem in Land Assembly.” FRB Atlanta Working Paper No. 2013-19. Available at SSRN: http://ssrn.com/abstract= 2579904 [8] Daughety, A., and J. Reinganum. (1994). “Asymmetric Information Acquisition and Behavior in Role Choice Models: An Endogenously Generated Signaling Game.” International Economic Review, 35 (4), 795-819. [9] Dewatripont, M., and E. Maskin. (1995). “Contractual Contingencies and Renegotiation.” RAND Journal of Economics, 26, 704-19. [10] Evans, R. (1989). “Sequential bargaining with correlated values. ” The Review of Economic Studies, 56.4, 499-510. [11] Fu, D., Y. McMillen, and T. Somerville (2002). “Land Assembly: Measuring Holdup.” University of British Columbia, CUER Working Paper 02-08. Available at https:// circle.ubc.ca/handle/2429/50535 [12] Fudenberg, D., and J. Tirole (1983). “Sequential bargaining with incomplete information.” The Review of Economic Studies, 50.2, 221-247. ¨ [13] Goller, D., and M. Hewer.“Breakdown in multilateral negotiations.” Journal of Economic Theory 157 (2015): 478-484. [14] Greenstein, M., and K. Sampson. Handbook for Judicial Nominating Commissioners. American Judicature Society, 2004. 33
[15] Gul, F., and H. Sonnenschein (1988). “On delay in bargaining with one-sided uncertainty.”Econometrica, 601-611. [16] Horn, H., and A. Wolinsky (1988). “Worker substitutability and patterns of unionization.” Economic Journal, 98, 484-497. ¨ [17] Horner, J., and N. Vieille (2009). “Public vs. private offers in the market for lemons.” Econometrica, 77.1, 29-69. [18] Hwang, I., and F. Li (2017). “Transparency of outside options in bargaining.“ Journal of Economic Theory, 167, 116-147. [19] Kaya, A. (2010). “When does it pay to get informed?” International Economic Review, 51(2), 533-51. [20] Kelsky, K. “The Professor Is In: On Interview Order,” https://chroniclevitae.com/ news, Date accessed: November 6, 2015. [21] Kessler, A. (1998). “The Value of Ignorance,” RAND Journal of Economics 29, 339–54. [22] Krasteva, S., and Yildirim, H. (2012a). “On the role of confidentiality and deadlines in bilateral negotiations.” Games and Economic Behavior, 75(2), 714-730. [23] Krasteva, S., and Yildirim, H. (2012b). “Payoff uncertainty, bargaining power, and the strategic sequencing of bilateral negotiations.” RAND Journal of Economics, 43(3), 514-536. [24] Lippman, S., and J. Mamer. (2012) “Exploding offers.” Decision Analysis 9(1): 6-21. [25] Mailath, G. (1993) “Endogenous Sequencing of Firm Decisions,” Journal of Economic Theory, 59, 169-82. [26] Marx, L., and G. Shaffer (2007). “Rent Shifting and the Order of Negotiations,” International Journal of Industrial Organization, 25(5), 1109-25. [27] Moresi, S., S. Salop, and Y. Sarafidis (2008), “A Model of Ordered Bargaining with Applications.” Available at SSRN: http://ssrn.com/abstract=1287224 [28] Niederle, M., and A. E. Roth. (2009). “Market culture: How rules governing exploding offers affect market performance.” American Economic Journal: Microeconomics, 199-219.
34
[29] Riordan, M. “What Is Vertical Integration?” In M. Aoki, B. Gustafsson, and O.E. Williamson, eds., The Firm as a Nexus of Treaties. London: Sage Publications, 1990. [30] Sebenius, J.K. 1996. Sequencing to build coalitions: With whom should I talk first? In Wise choices: Decisions, games, and negotiations, edited by R. J. Zeckhauser, R. L. Keeney, and J. K. Sebenius. Cambridge, MA: Harvard Business School Press. [31] Taylor, C., and H. Yildirim. (2011) “Subjective Performance and the Value of Blind Evaluation.” Review of Economic Studies, 78, 762-94. [32] Vincent, D. (1989) “Bargaining with common values.” Journal of Economic Theory, 48.1, 47-62. [33] Wheeler, M. (2005) “Which Comes First? How to Handle Linked Negotiations.” Negotiation 8, no.1. [34] Willihnganz, M., and L. Meyers. (1993) “Effects of time of day on interview performance.” Public Personnel Management 22(4): 545-550. [35] Xiao, J. (2015) “Bargaining Order in a Multi-Person Bargaining Game,” University of Melbourne Working Paper. Available at SSRN: http://ssrn.com/abstract=2577142
35
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|
http://tex.stackexchange.com/questions/11827/adding-an-authoryear-block-at-the-beginning-of-bibliography-entries
|
# Adding an [AuthorYear] block at the beginning of bibliography entries
I want to add a block at the beginning of my bib entries of the form
[Lastnameauthor(s) Year]
When the shortauthor field is defined it should use this field +Year instead. The following example is fairly minimal:
\begin{filecontents*}{test.bbx}
\ProvidesFile{test.bbx}
[\abx@bbxid $Id: test.bbx,v 0.9d 2010/09/03 20:11:58 lehman beta$]
\RequireBibliographyStyle{authoryear}
\DeclareBibliographyDriver{article}{%
\usebibmacro{bibindex}%
\usebibmacro{begentry}%
\usebibmacro{author/translator+others}%
\setunit{\labelnamepunct}\newblock
\usebibmacro{title}%
\newunit
\printlist{language}%
\newunit\newblock
\usebibmacro{byauthor}%
\newunit\newblock
\usebibmacro{bytranslator+others}%
\newunit\newblock
\printfield{version}%
\newunit\newblock
\usebibmacro{in:}%
\usebibmacro{journal+issuetitle}%
\newunit
\usebibmacro{byeditor+others}%
\newunit
\usebibmacro{note+pages}%
\newunit\newblock
\iftoggle{bbx:isbn}
{\printfield{issn}}
{}%
\newunit\newblock
\usebibmacro{doi+eprint+url}%
\newunit\newblock
\setunit{\bibpagerefpunct}\newblock
\usebibmacro{pageref}%
\usebibmacro{finentry}}
\endinput
\end{filecontents*}
\begin{filecontents*}{MeineBib.bib}
@article{example,
author={Firstname Lastname and First Last},
title={Title},
journal={Journal},
year={Year},
pages={Pages},
}
\end{filecontents*}
\documentclass[12pt,ngerman, ]{scrartcl}
\usepackage[ngerman]{babel}
\usepackage{filecontents}
\usepackage[babel,german=quotes]{csquotes}
\usepackage [bibstyle=test]{biblatex}
\bibliography{MeineBib}
\begin{document}
\tableofcontents
\cite{example}
\printbibliography\end{document}
I'm guessing the solution lies here
DeclareBibliographyDriver{article}{%
\usebibmacro{bibindex}%
\usebibmacro{begentry}%
\usebibmacro{author/translator+others}%
but I can't find out how. It should look like this which is an existing style (natdin) in BibTeX, but not in biblatex.
-
Way back, I answered a very similar question at the German-speaking forum mrunix.de. The trick is to add \usebibmacro{cite} to the bibmacro begentry (which does nothing by default). Then choose the citestyle authoryear and the bibliography style authortitle, sort the bibliography by author-year-title, remove dashes for recurrent authors ... and you're set. ;-)
\documentclass{article}
\usepackage[citestyle=authoryear-comp,bibstyle=authortitle,sorting=nyt,dashed=false,%
maxcitenames=1]{biblatex}
\newcounter{mymaxcitenames}
\AtBeginDocument{%
\setcounter{mymaxcitenames}{\value{maxnames}}%
}
\renewbibmacro*{begentry}{%
\printtext[brackets]{%
\begingroup
\defcounter{maxnames}{\value{mymaxcitenames}}%
\printnames{labelname}%
\setunit{\nameyeardelim}%
\usebibmacro{cite:labelyear+extrayear}%
\endgroup
}%
}
\DeclareNameAlias{sortname}{first-last}
\usepackage{filecontents}
\begin{filecontents}{biblatextest.bib}
@misc{A01,
author = {Author, A. and Buthor, B.},
year = {2001},
title = {Alpha},
}
\end{filecontents}
\begin{document}
Some text \autocite{A01}.
\printbibliography
\end{document}
EDIT: Improved redefinition of begentry to allow for cases where maxnames differs between in-text-citations and the bibliography. (\defcounter is an etoolbox macro that allows [in contrast to \setcounter] for local redefinitions of counter values.)
EDIT 2: Removed need to manually set custom counter.
EDIT 3: Changed format of author names to first-last.
EDIT 4: Replaced \usebibmacro{cite} with lower-level commands in order to make example also work with comp styles (which compress recurring author names in citations).
(In case anyone is wondering about these piecemeal enhancements: This question has become sort of a "Parallel Campaign" to another question at mrunix.de.)
-
@ lockstep: Thanks a lot! As it turns out, my thoughts were way tooo complicated... – meep.meep Feb 23 '11 at 17:24
Just to mention - I hope to implement user-definable labelapha in biber soon and so these labels will be customisable. – PLK Jun 25 '11 at 8:20
The \usebibmacro{cite:labelyear+extrayear}% should be replaced by \printfield{labelyear}% \printfield{extrayear}% for the entry not to be linked, since links doesnt make sence in the bibliography – Skip Jan 20 '12 at 22:20
When trying this minimal example I get ! Package keyval Error: maxcitenames undefined. Is this a problem with the version of biblatex? – pirad Mar 24 '12 at 8:44
@pluton Add \renewbibmacro*{author}{}. – lockstep Jan 25 '13 at 8:36
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https://jacopofarina.eu/posts/fleximatcher-parse-natural-language/
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Note: this is an old article and while the software is still available and I think the idea is pretty you probably want to give a look to this. The software here described is probably more flexible, but harder to use.
Some months ago, I stumbled across this amazing article about transforming an arbitrary English text in a patent application. The underlying pattern library allows, among other nice things, to find patterns like “*The [an adjective] [a noun] and the [a noun]*” easily, look for hypernyms (“is a” relationships between expressed concepts, for example “animal” is an hypernym of “cat”) in WordNet, and conjugate verbs in various languages comprehending Italian.
With a library like this extracting information from text becomes a lot easier, but unfortunately there are no exact replacements for this in Java, and the coverage of Italian is partial (no hyperonymy information, a small set of PoS tags), so why not try to create a specific library in Java?
# Reinventing the wheel: UIMA and GATE
At first the idea was to integrate a PoS tagger like the one from OpenNLP and match expressions like “*The [pos:ADJ] [pos:SS] and the [pos:SS]“, or “[hyp:animal]” allowing the user to easily express patterns and look for them, then I started thinking about additional patterns like “[r:[a-z]+[0-9]]” to match regular expressions, or “[reddit_nick]*” to match Reddit usernames, and found that providing a set of core expressions and letting the users define their own could be way more useful.
Moreover, an user may want to define expressions to match common patterns, for example “[r:[1-9][0-9]] [r:[AP]M]*” may be assigned to the tag “*hour*” in order to directly write expressions like “*it’s [tag:hour]*” to match “*it’s 3 PM*“, so user-defined expressions may recursively match patterns with other expressions. This is exactly what generative grammars do, and while we are at it why not let the user defined expression add metadata to the matched text and read metadata added by other rules?
If this does ring a bell, it’s because the idea isn’t new: annotation engines like UIMA and GATE do exactly this.
The problem is that those are both pretty hard to use and configure, though uimaFIT is somehow making things easier, and I wanted a library that could be used immediately and embedded in an application without writing XML configuration files, installing Eclipse plugins or use standalone extra applications to test the results.
So, a Java 8 library called Fleximatcher was born. The name stands for flexible matcher (my boss says I’ve plenty of fantasy 🙂 ) The usage is pretty simple:
1. Add expressions (the pos or hyp in the examples above) and bind them to your annotators, or use built in annotators.
2. Add tags, that are expressions matching patterns (the hour tag above).
3. Ask the library whether a string matches a pattern, and if so which part of the string match which expressions, and which annotations are returned.
JSON is adopted as a format to express annotations, and to define tags, which in the end are rules of a generative grammar, is possible to load a TSV file in this format:
adjective_attribution [it-pos:Ss] [it-pos:As] {‘name’:#0#,’attribute’:#2#}
The first rule matches Italian singular names (Ss) followed by Italian singular adjectives (As), and create a JSON string with the keys name and attribute and the name and adjective as values, since #0# is the first matched expression, #1# is the space between them and #2# is the annotation.
The second rule takes what was marked by the first and encapsulate it in another JSON string, taking the attributes from it.
This way is possible, with a single line of a TSV file, to define rules that generate annotations based on annotations from other rules, reading both the annotated text spans and the annotation attributes. It’s also possible to define more complex tags with a custom tag class.
Using about 70 rules it was possible to extract hyponyms, adjective attributions to names and subjects and objects of verb from a whole dump of Wikipedia, a topic I’ll talk about another time.
# Parsing with no leftmost derivation
The parser is a top-down one, it tries to match the expressions composing the given pattern and expand tags by matching the correspondent patterns. Since expressions like PoS tags are identified by looking at the surrounding text, and ambiguous grammars are fine (multiple interpretations can be returned), leftmost derivation used by LL parsers is difficult to get.
To be faster the parser uses a trick (two if we consider caching): since annotators can only add annotations, never remove or modify existing ones, if an annotator is called twice on the same text and with the same number of annotations, we can safely assume that the second time it will not retrieve anything, and avoid trying.
This is done by analyzing the chain of annotation handlers. Annotation handlers are for Fleximatcher what the CAS is for UIMA: an element which stores annotations from different annotators. Fleximatcher annotation handlers are of course a lot simpler, they just allows annotators to store and retrieve annotations which are kept in memory, but offer the possibility of searching for sequences of adjacent annotations and get sub-handlers which are wrappers passed around when expanding an expression to its own pattern.
Each time a tag is asked to annotate a text, it checks whether it was called previously querying the annotators up to the hierarchy and the amount of annotations. If it finds another one with the same number and the same tag expression, it means that due to the deterministic nature of annotators it won’t add annotations and the recursion stops.
This is done not just for efficiency, but also to let the user detect cycles and anomalies int he given grammar: if we can exclude “fake” cycles there’s less noise hiding real ones, which throw specific exceptions when found.
To make the parsing easier, a PoS tagger for Italian, based on OpenNLP and with tens of different words, is already present, and a web application allows to define tags and test patterns on text on the fly, seeing the results in a webpage
The application is just a REST interface to Fleximatcher, and allows to call the library from other languages.
It would be nice to adapt the library to Apache Stanbol enhancement engine, while for UIMA the project Ruta seems a better fit.
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https://www.groundai.com/project/design-of-a-surface-trap-for-freely-rotating-ion-ring-crystals/
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Design of a Surface Trap for Freely Rotating Ion Ring Crystals
# Design of a Surface Trap for Freely Rotating Ion Ring Crystals
Po-Jen Wang Department of Physics, University of California, Berkeley, California 94720, USA Tongcang Li NSF Nanoscale Science and Engineering Center, 3112 Etcheverry Hall, University of California, Berkeley, California 94720, USA Crystal Noel Department of Physics, University of California, Berkeley, California 94720, USA Xiang Zhang NSF Nanoscale Science and Engineering Center, 3112 Etcheverry Hall, University of California, Berkeley, California 94720, USA Hartmut Häffner Department of Physics, University of California, Berkeley, California 94720, USA
July 15, 2019
###### Abstract
We present a design of an r.f. trap using planar electrodes with the goal to trap on the order of 100 ions in a small ring structure of diameters ranging between 100 m and 200 m. In order to minimize the influence of trap electrode imperfections due to the fabrication, we aim at trapping the ions around 400 m above the trap electrodes. In view of experiments to create freely rotating crystals near the ground state, we numerically study factors breaking the rotational symmetry such as external stray electric fields, local charging of the trap electrodes, and fabrication imperfections. We conclude that these imperfections can be controlled sufficiently well under state-of-the-art experimental conditions to allow for freely rotating ion rings even at energies comparable to the ground state energy of the rotational degree-of-freedom.
###### pacs:
preprint: APS/123-QED
## I Introduction
The electronic and motional degrees-of-freedom of ions trapped with electromagnetic fields are extremely well decoupled from their environment. In addition, lasers and electromagnetic fields allow for excellent control of both degrees-of-freedom on the single quantum level Leibfried et al. (2003); Häffner et al. (2008). Both of those properties make ion crystals nearly perfect systems to study many-body physics in closed systems Friedenauer et al. (2008); Richerme et al. (2014); Jurcevic et al. (2014); Ramm et al. (2014). While most experiments are carried out with linear ion strings, a particularly interesting structure is a ring of trapped ions. Proposals include mini-accelerators Blümel and Smaldino (1999); Schätz et al. (2001), dynamics of KinksLanda et al. (2010), quantum emulation of ring molecules, and the acoustic analog of Hawking radiation Horstmann et al. (2010). Recently, also rings of trapped ions have been suggested to realize the concept of so-called time crystals Wilczek (2012); Li et al. (2012).
However, starting from experiments on how to implement rings of trapped ions by Schätz et. al. Waki et al. (1992); Schätz et al. (2001), it has become clear that imperfections and charging will make it very hard to implement such experiments. Thus, a few design improvements have been proposed Lammert et al. (2006); Austin et al. (2007); Madsen and Gorman (2010). Furthermore, the Sandia group has implemented a ring trap on surface trap technology Tabakov et al. (2012). Common to those designs and experiments is that the resulting ring potential has relatively large diameters, making it difficult to compensate for imperfections.
Inspired by Ref. Clark (2013), we study a novel design, deviating from the idea of bending a conventional linear trap into a ring. In addition, with a planar electrode design amenable to microfabrication, we seek to reduce inevitable imperfections from the geometry as well as local charging of trap electrodes. The main feature of our geometry is to trap the ion ring far away from the trapping electrodes as compared to the typical ion-ion distance and the ring diameter itself. Thus local imperfections from stray charges affect the rotational symmetry of the ion ring much less as if the ions were trapped close to the trap electrodes.
Our design is composed of concentric planar ring electrodes (see Fig. 1). Trapping is accomplished by applying suitable radio frequency (rf) voltage to those rings. Work by Clark suggest that the multipoles of such a trapping potential can be adjusted over a wide range by changing the rf voltage on the various rings Clark (2013). However, it is experimentally difficult to keep several rf high-voltage sources in phase. We thus design a trap requiring only one rf high-voltage source. Fixing this parameter, we aim to find a trap geometry yielding a rotationally symmetric potential minimum at the desired ring diameter and height.
For the study of the physics of symmetrization of the wavefunction of bosonic and fermionic ions discussed in the context of time crystalsWilczek (2012); Li et al. (2012), it will be important that the ion ring can freely rotate at the level of single rotational quanta. Keeping that in mind, we consider identical ions with mass and charge in a ring trap with diameter and a uniform magnetic field. The energy scales of its internal vibration modes are much larger than the energy scale of its collective rotation Burmeister and Maschke (2002). Thus, we focus on the collective rotation. Because of the required symmetrization of identical ions, the canonical angular momentum of the ion ring will be quantized according to for identical bosons, where is the quantum number of the rotation. The kinetic angular momentum is and the eigenenergy of the collective rotation is for identical bosonic ions, where is the normalized magnetic flux. This provides an energy scale of
Egap=Nℏ2Md2. (1)
For identical fermions, the energy scale is the same, although its dependence on can be different. For an ion ring of 100 Ca ions with a diameter of 100 m, the energy scale of the collective rotation is nK. We seek to create a ring potential with sufficiently small imperfections such that a classical ion ring with rotational energy corresponding to the ground state energy would not be pinned by the imperfections.
In view of these considerations, it is important to trap the ion ring far away from trapping electrodes, while at the same time keeping the ion ring as compact as possible. Thus, heating is reduced while still maintaining a reasonable energy scale of the ground state. Additional design constraints are ease of symmetric trap fabrication as well as reasonable trapping voltages while maintaining an appreciable trap depth. To this end we target an ion ring with a diameter of 100 m trapped 400 m above the trap electrodes.
The remainder of the paper is organized as follows. In Sec. II, we briefly summarize the methods outlined in Ref. Clark (2013) on how to efficiently calculate rotationally symmetric potentials. Armed with the potential, we study the structure of ion crystals forming in such ring shaped potentials in Sec. III. We then analyze various imperfections breaking the rotational symmetry in Sec. IV, most notably external stray fields, electrode edge irregularities, and local charging of the trap electrodes. Sec. V addresses the process of cooling and pinning such a ring of ions.
## Ii Calculation of the trapping potential
We start with the trap design proposed in Ref.Clark (2013) composed of planar ring electrodes of different radii and applied voltages. Given this cylindrically symmetric boundary condition, the analytic solution to Laplace’s equation is given by Kim et al. (2010)
Φ(z,r)=∫∞0J0(kr)e−kzA0(k)dk. (2)
where is the Bessel function of order. can be expressed as , and is given by
Ai(k)=Vi(biJ1(kbi)−aiJ1(kai)). (3)
where and are the outer and inner radius of each ring electrode and is the amplitude of the rf voltage applied to the each electrode. In order to study ions in this oscillating trapping potential, we approximate the potential by the time-averaged pseudopotential
Ψ(z,r)=Q24MΩ2rf|→E(z,r)|2. (4)
This approximation is valid when the oscillation frequency of the trapped ion is much smaller than the rf frequency.
### Trap design
Ref.Clark (2013) showed that multipole surface traps can be built from concentric rings with particular sets of ring diameters and applied voltages. However, it is experimentally difficult to keep several rf high-voltage sources in phase. We thus design a trap targeting only one rf high-voltage source. Our design, shown in Fig. 2, is composed of three concentric ring electrodes with outer radius 126 m, 600 m, 1100 m, with the second ring grounded and the other two connected to a fixed rf driving source of amplitude = 1000 V. As the rf driving frequency, we choose MHz. In what follows, we also assume Calcium ions with mass amu. The design leads to a Mexican-hat-shaped pseudopotential in the radial direction and a confining pseudopotential in the axial direction, as shown in Fig. 3. The trap potential has minimum at radius m, height 385 m, and a trap depth of 0.134 eV, leading to single-ion trap frequencies MHz and MHz in the radial and vertical direction, respectively.
### Design variation compensation
In view of fabrication imperfections, we study the effects of small deviation in the size of the center electrode. Our simulation Fig. 4 shows that the position of the potential minimum is very sensitive to the change in the size of the center electrode. In particular, it shows that changes of 1 m in radius will shift the radius of the minimum by 10 m. While we expect that microfabrication allows fabrication with tolerances below the micrometer range, we also can tune the potential by adding a small variable rf voltage with the same driving frequency on the second ring, but with the phase exactly opposite to that. Simulations show that the minimum position is shifted radially inward by about 2.5 m/V, while the trap depth changes by 0.005 eV/V. This small compensation rf voltage provides a powerful tool for fine-tuning the potential in situ.
## Iii Structure of ring crystals
Of particular interest are the conditions under which ultra-cold ions form a ring in this potential. For this, we carry out molecular dynamics simulation to analyze the structure of laser-cooled ions in the surface trap Okada et al. (2007). We calculate the trajectories and velocities of the trapped ions by solving Newtonian equations of motion including the Coulomb interaction, the pseudoforce from the rf potential, and a hypothetical damping force term Meyrath and James (1998). The extra damping term serves as a friction term that will gradually reduce the energy of the ions, thereby simulating laser cooling. Thus, the ions will eventually reach a steady state, which represents the expected structure of the cold ion crystal. The equations of motion of the ion can be written
mid2→xidt2=−γd→xidt+→FT+→FC. (5)
where is the damping coefficient, is the pseudoforce and the Coulomb force is given by
→FC=q24πϵ0N∑i≠j→ri−→rjR3ij, (6)
where is the number of ions in the trap.
Subsequently, the equation of motion is numerically solved by fourth-order Runge-Kutta method with a time step of 20 ns. For a reasonable run-time of the algorithm of a few hours, we choose the damping coefficient kg/s. As a result, our simulation shows that a ring crystal can be formed with up to 92 ions with the parameters and geometry discussed above (outer radius of the inner electrode 126 m). As shown in Fig. 5(a), the 92-ion ring has diameter 116 m and height 385 m,
Keeping all parameters fixed, but adding one more ion yields a 93-ion ring crystal of two layers with about 1 micrometer separation in the plane perpendicular to the trap surface, as shown in Fig. 5(b). We can study this phase transition from single-layer ion rings to double-layer ion rings by fine-tuning the trapping potential. This can be done by adjusting the compensation rf voltage on the second ring, as we have discussed in Sec. II. In the double layer regime, we also find meta-stable kinks as shown in Fig. 5(c). The kink dynamics in a ring might be an interesting subject in its own right Landa et al. (2010). Contrary to studies in linear traps Mielenz et al. (2013); Ulm et al. (2013); Pyka et al. (2013), the kinks are in a homogeneous environment and cannot escape by just traveling to the edge of the ion crystal. Furthermore, working with an odd number of ions enforces the presence of an odd number of kinks and thus of at least one, while working with an even number of ions would lead to an even number of kinks.
## Iv Analysis of imperfections
Of particular interest in our work is to create ion crystals freely rotating even if their rotational energy is comparable to the groundstate energy Li et al. (2012); Wilczek (2012). With with the criterion established in Eq. 1, i.e the energy barrier created by the imperfections should be be smaller than nK, we calculate the energy as a function of the angle when rotating the crystal around the symmetry axis. We study three sources of imperfections: a homogeneous electric field, irregularities on the edge of the electrodes, and the effect of a local charging (Fig. 6).
### Homogeneous Electric Field
First we calculate the energy of the ion ring as a function of rotation angle in presence of an homogeneous electric field. The result will be a sinusoidal periodic function whose amplitude represents the classical energy barrier, which we denote (c.f. Fig. 8). Fig. 7 shows the energy barrier as a function of the applied field for 10, 20, 30, 40, and 50 ions. Fig. 7 illustrates that the energy barrier is drastically suppressed when the number of ions is increased. Recall that the energy gap is also proportional to the number of ions, . This suggests that freely rotating crystals with larger ion numbers are easier to observe, and suffer less from the imperfection of the trap. Intuitively, this can be understood in the following manner: for an increased ion number, the ion-ion spacing is much reduced approaching a more homogeneous and continuous charge distribution. For such an homogeneous charge distribution external imperfections cannot exert a torque on the charge distribution. Thus, the rotational barrier caused by the imperfection drastically reduces with an increasing number of ions.
### Electrode Edge Irregularity
Next we add a square electrode of width 1 m (2 m) adjacent to the center electrode imitating a fabrication imperfection. The electric potential of a square electrode can be calculated from solving Laplace’s equation analytically Gotoh and Yagi (1971). We obtain the full potential by superposing this solution to the one obtained earlier. Fig 8 shows the energy of a 25-ion ring as a function of rotation angle with the square electrode of width 1 m and 2 m.
We concluded that already for 25 ions, the energy barrier is sufficiently small. Increasing the ion number reduces the ion-ion spacing which is expected to reduce the energy barrier further.
### Local Charge
In surface traps with ion-electrode distances on the order of 100 m, we typically find electric fields on the order of 100 V/m before performing micromotion compensation. These fields come potentially from local charges on the trap surface as caused for instance by small charged dust particles on the electrodes. To study the effects of this, we assume that a square of size 10 m 10 m at a position 200 m from the center, which carries a different voltage than the rest of the electrodes. By applying 1V to 50 V DC to the square electrode, we create electric field of strengths from 2 V/m to 100 V/m at the center of the ion ring 385 m above the surface. The result is presented in Fig 9. We find that already a 25-ion crystal is nearly insensitive to charging of a 10 m 10 m surface to tens of volts. Again, increasing the ion number will reduce the energy barrier further, and thus allow for even stronger local charge imperfections.
## V Laser Cooling
Finally, we study the laser cooling dynamics for freely rotating ion rings. In ion trapping experiments, usually a single cooling beam is preferred avoiding complications with interference effects. If this beam is centered perfectly on the ion ring, the radiation pressure will be balanced on each side of the nearly freely rotating ring. If, however, the beam is displaced from center, then a net torque from radiation pressure will result. Treating the ring as a rigid rotating body, we can apply the force equations for Doppler cooling Leibfried et al. (2003) and determine the net torque on the ring. In the limit of small velocities, at temperatures close to the Doppler cooling limit, we linearize the forces and the average torque on a single ion can be written as:
τa=R×F0(1+κv). (7)
where is a radial vector of each ion. is averaged radiation pressure in the direction of laser beam propagation,
|F0|=ℏkΓs/21+s+(2Δ/Γ)2. (8)
The drag coefficient for cooling,
κ=8kΔΓ2cosθ1+s+(2Δ/Γ)2. (9)
is negative when the detuning is negative. The arises from the projection of the laser onto the rotational degree-of-freedom of each ion, , where is the velocity of the ion. The decay rate is given as ns) for Calcium, the wavenumber is defined as nm), and is the saturation parameter Leibfried et al. (2003). In what follows, we assume a saturation parameter of and a gaussian beam profile with a beam waist of 200 m. We chose a large beam waist to minimize the differences in intensity across the ring of ions and assume a detuning of MHz for optimal cooling.
The Doppler cooling action of the laser on the moving ions will counterbalance the torque from the radiation pressure. If the torque is sufficiently small, the forces will cancel at some finite frequency of rotation. For 30 ions confined to a m ring, we calculate the equilibrium frequency and find a rotation frequency of approximately 1.04 kHz per 1 m displacement of the cooling beam.
To counteract the rotation, we turn to the previous discussion of the effects of electric fields on the ring. By applying a strong electric field, we aim at creating a sufficiently strong energy barrier, thus stopping the ion ring from rotating. The maximum slope of the energy of the ion crystal as function of the rotation angle represents the torque needed to overcome the energy barrier and cause the ions to rotate around the ring
τE=∣∣∣dEdθ∣∣∣max. (10)
Aiming at a static ion crystal, the torque from the cooling laser on a single ion is . Next, we look to find an applied electric field that will cancel the torque from the laser for this displacement. This condition can be written as
N∑i=1τiL<τE. (11)
where represents the sum over the torque of all ions by a given electric field, with the field orientation chosen to maximize the torque, c.f. Fig. 10b).
For ion positions in the trap given an electric field of 75 V/m optimally aligned against the propagation of the laser, the total sum of the torque from the laser alone is approximately linear for small laser displacements d. Analyzing the situation for 30 ions and taking into account their calculated positions in the ion ring, we obtain N. The torque from the energy barrier for 75 V/m, given by the maximum slope of the curve in Figure 11, is Nm, allowing for a displacement d of up to 6.0 m to achieve a static ion crystal.
## Vi Conclusions
We have studied a design of a planar trap providing trapping of a 92 ion-ring of diameter 116 m at height 385 m above its surface. This design can be fabricated using micro-fabrication methods with high precision. We also studied the rotational motion under three symmetry-breaking imperfections: homogeneous electric fields, irregularities of electrode edges from fabrication imperfections, and local charges placed on the trap electrodes. We have shown that the rotational energy barrier induced by these imperfections drastically reduces with an increasing number of ions in the ring. We thereby expect that the energy barrier from the imperfections can be reduced below the rotational ground state energy of large ion crystals. In addition, we have shown that laser alignment and strong homogeneous electric field of 75 V/m can be utilized to pin and cool the ion ring for trapping and imaging.
## Acknowledgements
This work is supported by the W.M. Keck Foundation. We acknowledge the contributions of Anthony Ransford and Hao-kun Li to the discussions related to this work.
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https://codeforces.com/blog/entry/13622
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### StoneCold_'s blog
By StoneCold_, 5 years ago, ,
Please can anyone provide a good implementation of trie using a 2D array instead of using recursion ?
• -1
» 5 years ago, # | +1 let f be the matrix representation of your trielet f[k] be the list of links for the k-th nodelet f[k][x] = m, the node who represents the son of k-th node using x-th character, m = -1 is there is not a link. int MAX = Max number of nodes int CHARSET = alphabet size int ROOT = 0 int sz = 1; f[MAX][CHARSET] void init() { fill(f, -1); } void insert(char [] s) { int node = ROOT; for (int i = 0; i < size(s); i++) { if ( f[node][ s[i] ] == -1 ) f[node][ s[i] ] = sz++; node = f[node][ s[i] ]; } } Notes: Root node is at f[0] sz is the numbers of nodes currently in trieI guess would be easy to you implement other functions.
• » » 2 years ago, # ^ | 0 can you explain it by taking an example?
• » » 2 years ago, # ^ | 0 It is an explanation where you are storing the size of the trie ..But it is not suitable when we need to use this for finding the prefixes or calculating the xor or something like that ...Is it ???
• » » 15 months ago, # ^ | -8 How to mark a complete word? Using another array of same size of f? If we can't mark complete word, incomplete word will be found by searching.
» 5 years ago, # | 0 It's my implementation of trie without using recursion and with using 2D array.
• » » 4 years ago, # ^ | 0 Nice code!! Thanks a lot.. Helped a lot
• » » 3 years ago, # ^ | -22 chrome Can you please explain your code. It would be really nice and helpful.
• » » 17 months ago, # ^ | -12 Thanks chrome!
• » » 9 months ago, # ^ | -8 thanks,,can you plz add a delete operation?
» 4 years ago, # | -8 You can find it in PrinceOfPersia's blog on data structures.
» 3 years ago, # | 0 My code hereI like this because 'add' and 'query' are in the same function (:
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https://www.physicsforums.com/threads/lagrangian-dynamics-problem-need-help-with-setup.100378/
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# Lagrangian Dynamics problem - need help with setup
1. Nov 17, 2005
### don_anon25
Lagrangian Dynamics problem -- need help with setup
Here's the problem:
A simple pendulum of length b and bob with mass m is attached to a massless support moving horizontally with constant acceleration a. Determine the equations of motion.
For the pendulum, x = b sin theta and y = b cos theta (Which of these equations should I use? y = b cos theta?)
For the support, x = (v0)t +.5a*t^2 - b sin theta? Is this correct?
Kinetic energy is 1/2 m (x'^2+y'^2), correct?
Potential energy is U=mgy.
If my equations are wrong, could someone tell me why and how to correct them? Your help is greatly appreciated!!!
2. Nov 17, 2005
### Physics Monkey
Remember that the support is massless so it has no kinetic or potential energy; you should just think of the support as being accelerated externally. To find the Lagrangian, you need only know the kinetic and potential energy of the pendulum, right? Start by writing the position of the pendulum relative to the support (hint: this is your usual pendulum position), and then write the position of the support relative to fixed lab (hint: this term should involve the acceleration). Once you have these two pieces, add them to obtain the position of the pendulum relative to the inertial frame. From this you can calculate the kinetic and potential energies and thus the Lagrangian.
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https://learn.careers360.com/ncert/question-describe-the-oxidising-action-of-potassium-dichromate-and-write-the-ionic-equations-for-its-reaction-with-iron/
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Q
# Describe the oxidising action of potassium dichromate and write the ionic equations for its reaction with: iron
8.15 Describe the oxidising action of potassium dichromate and write the ionic equations for its reaction with:
(ii) iron(II) solution
Views
Potassium dichromate react with $(Fe^{2+})$ ion to produce solution of $(Fe^{3+})$ ion and chromium reduced to +3 oxidation state.
$\\Cr_{2}O_{7}^{2-}+14H^{+}+6e^{-}\rightarrow 2Cr^{3+}+7H_{2}O\\ Fe^{2+}\rightarrow Fe^{3+}+e^{-}]\times 6$
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$\\Cr_{2}O_{7}^{2-}+14H^{+}+Fe^{2+}\rightarrow 2Cr^{3+}+7H_{2}O+ 6Fe^{3+}$
Exams
Articles
Questions
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https://wiki.ubc.ca/Course:CPSC522/User-Adaptive_Information_Visualization
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# Abstract
## Builds on
User adaptive visualization is studied in the intersection area of three fields of Human Computer Interaction, Information Visualization, and Machine Learning.
## Related Pages
Predicting Affect of User's Interaction with an Intelligent Tutoring System can be seen as an attempt to infer the affective states that are discussed in the second study (Feedback), that I describe in this page. General Linear Model (GLM) is an ANOVA procedure incorporates a least squares regression technique to explain the statistical relationship between some predictors such as factors and/or covariates and a continuous response variable.
GLM repeated measure as a statistical technique is commonly used in the experiments that include intervention such as the two described in this page, measuring the effect of a treatment at different time points. It takes a dependent, or criterion variable, measured as correlated, non-independent data. it tests the main effects within and between the subjects, interaction effects between factors, covariate effects and effects of interactions between covariates and between subject factors.
# Introduction
The field of Information Visualization (InfoVis) used to comprise of a one-size-fits-all approach, in which, end-user differences were not taken into consideration [3]. However, in recent years, a series of important questions were evolved such as, what if we look at a visualization as an intelligent agent that can play an active role in the environment, that is able to reflect to feedbacks of its actions and improve itself? In other words, what if we make it to be able to adapt to the specific features of environment including characteristics of end-users, it is interacting with, in order to let it tune itself and enhance its effectiveness?
The attempts to answer this kind of questions, formalized a group research work: User-Adaptive Information Visualization (U-AIV) and also justified its association with Artificial Intelligence (AI).
As it is pointed out in the first study that we review in this work [1], we define and categorize research studies in U-AIV as attempts to address all, or a part of any of the following three questions:
• What user distinctions (i.e personal, cognitive, interactional, task differences, etc.) should be targeted to adapt to?
• What is the best time during the interaction to adapt, in order to maximize the effectiveness?
• What strategy should we take in order to adapt to user distinctions?
## AI In U-AIV
The other AI’s direct techniques and artifacts such as sequence planning models (HMM, Max Entropy Markov Model, etc.) come useful when advanced problems of U-AIV are investigated such as sequential presentation of adaptive support in a course of a process. However, as the main goal of this page was to introduce the field by two papers from two different research teams, I decided to select a set of two papers, that present a smooth introduction to the type of problems that are investigated in U-AIV. Without exposure to the following fundamental perceptions, discussing the advanced problems would not seem to be reasonable.
## Related Work
To the best of my knowledge, the following studies have been conducted to address the three key decisions of what, when and how to adapt in designing adaptive systems.
Selecting features to adapt, yields many studies aimed to identify the criteria that have the potential to make differences in users' experience such as their performance , in order to discriminate users based on them:
• Cognitive measures of Perceptual Speed and Spatial Visualization were shown to affect user performance among different visualizations and task types in [4], [5], and [6]
• The personality trait of Locus of Control was shown and regarded as a potential feature to adapt to in [7], [8]
• Cognitive abilities of Visual Working Memory, Verbal Working Memory, and Visualization Expertise were shown in [5] as important adaptation features.
The best time of delivering adaptations to overweight their potential interruptions is mainly investigated in two major fields of Intelligent Tutoring [9] and Availability Management Systems [10]. However, the following studies were carried out with the similar objective in Information Visualization:
• An approach to infer the need for intervention by real-time monitoring user behavior was presented in [11]
• A user study designed to capture the confusion moments of users during visualization was described in [12]
Strategies for designing an adaptive system have been mainly pursued between two polarities of suggesting alternative visualizations in one side, and improving the current visualization on the other side, based on user differences, in order to enhance the experience. The nature of some strategies doesn't let me to classify them with certainty in any of these sides, therefore, the following classification is based on their tendencies.
Recommending Alternative Visualization:
• A work in which the system recommends distinct representation such as a pie chart, plot chart, bar chart, sector graph, Euler's diagram, or table was described in [13]. The adaptive system recommends these representations based on four features (what to adapt): user expertise, user preference, the task's information to be visualized, and representation's semantics.
• An adaptive system designed to improve the accuracy of external representation (ER) selection of users on a range of database query tasks was presented in [14]
• An adaptive system that is able to suggest alternative visualization based on the task that a user intends to do with visualization was introduced in [11]
• A system that dynamically adapts the visualization of the search results according to emerging interests of users was outlined in [15]
Enhancing The Effectiveness of Current Visualization:
• Detection and distraction of notifications were studied based on their motions across some information-rich interfaces in [16]
• Adaptive hints were investigated in an educational game in [17]
• [ Selected ] The effectiveness of four different highlighting interventions on current visualizations (Bar graphs) based on three major categories of features (what to adapt): task complexity, user characteristics, delivery time was investigated in [1].
• [ Selected ] The effectiveness of two different forms of feedback presentation based on users affective states was studied in [2]
## Focus
Among all studies that had been conducted during recent years in U-AIV, I selected the last two studies that were outlined in the previous section to describe in this work:
1. Highlighting interventions and user differences: informing adaptive information visualization support (2014) [1]
• We refer to it as Highlight study.
2. Light-Bulb Moment?: Towards Adaptive Presentation of Feedback based on Students' Affective State (2015) [2]
• We refer to it as Feedback study.
The contribution of the second study was to expand the research work on studying different possible strategies and forms of adaptation (How to adapt). One reason for choosing these two studies is that, the second one is conducted by a completely different team, in a different region of the world (Europe, University of London) to continue the chain of studies conducted by the team of first study (North-America,University of British Columbia). Therefore, the second study may consider as a good example of a contribution.
In the following sections, I briefly describe the Highlight study first, and then I review the Feedback study in detail.
# Highlight Study
## Overview
The first chosen study (Highlight) [1], defined the space of research work regarding U-AIV systems as a series of attempts to address three key decisions of what, when, and how to adapt by user-adaptive system designers. The classification of related work in this page has been performed based on this definition.
The next step in Highlight study was to address the last question (How to adapt) by investigating the relative effectiveness of four highlighting interventions of Bolding, De-Emphasizing, Reference Lines, Connected Arrows which are shown in Figure 1.
Highlighting intervention refers to an attempt or a strategy to enhance the effectiveness of the information visualization that a user is currently viewing. Subsequently, above highlighting interventions were designed to help users in the processing of different visualization by highlighting relevant elements for performing the objective tasks.
Figure 1. Interventions used in the study [1]
The effectiveness of these highlighting interventions was investigated based on two main criteria. First, the task complexity which is comprised of a Retrieve Value (RV) task: "Given a set of specific cases, find the attribute of those cases" [18], and a Computed Derived Value (CDV) task: "Given a set of data cases, compute the aggregate numeric representation of those data cases" [18] as a simple and a complex visualization task. Second, the delivery time which is comprised of delivering interventions at the beginning (${\displaystyle T_{0}}$) or at the time ${\displaystyle X}$ during the course of visualization processing (${\displaystyle T_{X}}$).
The result was also further discriminated based on the important factor of user characteristics which include:
• Visual Working Memory (VisWM) : A measure of storage and manipulation capacity of visual and spatial information
• Verbal Working Memory (VerbWM) : A measure of storage and manipulation capacity of verbal information
• Perceptual Speed (PS) : A measure of speed in performing simple visual task
• Locus of Control (LC) : A measure of the degree to which one would perceive outcomes as either the result of his/her own behavior, or from some imposed external forces
• Visualization Expertise (VisExp) : A measure of having prior experience of working with simple or complex visualization
## Research Questions
The initial research questions in this study were:
1. Can highlighting interventions improve information visualization processing?
2. Is there an intervention that is the most effective?
3. Are questions 1 and 2 above affected by individual user characteristics, by task complexity, and by when the interventions are delivered?
## Research Procedure
Figure 2. Example bar graph visualization as used in the experimental tasks [1]
The experiment was a within subject study, it was taken place over 62 recruited subjects, ranging in age from 18 to 42. They were comprised of 55 students and 7 non-students and they had selected from diverse backgrounds. Before the experiment began, they completed a series of standard computerized tests for the purpose of user characteristics measurement (Table 1). In the course of the experiment, participants were asked to do a set of RV and CV tasks designed to be done using bar graphs (Figure 2). After the experiment, they also took a post questionnaire asking for their evaluation of each intervention's usefulness, along with their relative preferences. Ultimately, General Linear Model (GLM)-repeated-measures was used for user performance analysis.
Table 1. Descriptive statistics of user characteristics [1]
## Findings
The result of this study indicates that in terms of both a user's performance (Figure 3) and user's perceived usefulness (Figure 4), all of tested highlighting interventions are effective in comparison to receiving no interventions, except for the average Reference Lines.. These can enhance a user's visualization processing experience (Question 1).
Figure 3. Performance score for each intervention. All bar graphs are shown with 95% confidence intervals [1]
Figure 4. Usefulness ratings for each Intervention [1]
No individual highlighting intervention was found to be the most effective one. De-emphasizing always the absolute best when it was provided from beginning (${\displaystyle T_{0}}$, Figure 6) and only on simple type (RV) tasks (Figure 5) (Question 2).
Figure 5. Interaction between Interventions and Task Type [1]
Dynamic delivering of interventions (at time ${\displaystyle T_{X}}$) did not neutralize their effectiveness in comparison to no interventions (Figure 6), which denotes that, their benefits outweigh their possible intrusiveness (Question 3). This finding implies that further research can be conducted to find the optimal ${\displaystyle T_{X}}$.
Figure 6. Interaction between Delivery Time and Interventions on task performance [1]
Task complexity significantly impacts user performance based on cognitive abilities of VerbWM, VisWm, and PS (The higher, the better) (Question 3). However, this study failed to find a similar result based on user characteristics of LC and VisExp (Question 3). Figure 7 illustrates the relation of VerbWM,PS with task types. A similar trend obtains for VisWm and task types.
Figure 7. Interaction between: Perceptual Speed and Task Type (left); VerbalWM and Task Type (right) [1]
## Conclusion
The findings of this study reaffirm and emphasize that, the participants with low-cognitive measures can benefit the most from support of adaptive interventions. Highlighting interventions can be very useful in cases in which, a variety of inferences from a set of visualized data sets are required, as users can concentrate on the most relevant parts of the graphs.
This study were carefully and intelligently designed; it tested the most promising highlighting interventions based on meticulous literature review, and conducted a highly controlled experiment. This study focused on bar graphs and well justified its decision by outlining bar graphs' generality aspects.
Nevertheless, it seems that, some weak procedure was followed for testing interventions based on the delivering time, which is prone to many conceptual and computational errors. Researchers have outlined that due to not having a criterion for deciding when to present interventions in dynamic delivering part, they decided to present it once the user had a chance to look at both bar graph and the related task questions. Moreover, the set of tasks was limited in terms of diversity; for instance, all were involved comparing something to the average of a group of data points. Therefore, they may not be representative of common visual analytical tasks. Future development can certainly investigate these matters further.
In the following section, we will see how another team adapted the framework of what, when, and how to adapt, and contributed to expand the body of literatures in the how-to-adapt branch of designing user adaptive systems.
# Feedback Study
## Overview
The second chosen study (Feedback) [2], followed the space framework of three key decisions defined by the first study (Highlight) [1], and then contributed by investigating the effectiveness of two different presentation types of feedback based on student's affective state while they were carrying out a fix set of tasks in an exploratory learning environment.
According to Perkrun [19], Affective States (also referred to as Achievement Emotions) arise in a learning situation. They are associated with learning instruction, and achievement.
This study argues the vital role of affective states in a student's learning process; positive ones such as awe, satisfaction, or curiosity can lead to constructive learning and negative ones such as frustration, or disillusionment has the potential to inhibit learning.
The researchers were curious to know whether the presentation way of feedbacks should tune according to students affective states in order to support affect change in instances that affect is negative.
Specifically the effectiveness of the following two forms of presentation was studied:
• High-interruptive pop-up window (Figure 8)
• Low-interruptive light-bulb glow (Figure 9)
Figure 8. High-interruptive feedback - pop-up window that includes a feedback message [2]
Figure 9. Low-interruptive feedback - light bulb glows (on the right hand side), indicating that feedback is available [2]
Also the following 5 affective states were targeted in this investigation:
• Enjoyment
• Surprise
• Frustration
• Boredom
• Confusion
The first five affective states mentioned above, were selected as a subset of affective states that were previously identified in a research study by Pekrun [20], also the last one was selected, as it was previously shown in a study[21] to be significant in the learning process.
The ultimate goal of this study was to produce guidelines for adaptive feedback presentation (presenting feedback in one of the above mentioned fashions) when students are interacting with a learning environment, based on their affective states.
In the following sections I describe this study in more depth and I outline its interesting findings.
## Questions
Researchers were interested in two major questions:
1. Is there an effect of different presentations of feedback on a student's affective state?
2. Does a student's (final) perception of the learning environment and presented feedback differ, according to whether low or high- interruptive feedback is provided?
## Design
To address the above questions, researchers conducted an ecological valid Wizard-of-Oz study. Ecological valid studies are those in which, setup and settings approximate the real-world situations. Furthermore Wizard-of-Oz is a type of research experiment in the field of [Human-Computer Interaction (HCI), in which subjects believe to interact with an autonomous computer system, but in fact, it is fully or partially operated by an unseen human being.
## Participants
17 students, all in fifth year, ranging from 9 to 10-year old were participated in this study. The sessions took place in a typical classroom with multiple computers where other students were working with the learning platform (Not Wizarded) to make the study ecological valid.
## Procedure
1. Participants were randomly divided in two groups: 8 students in the high- and 9 students in the low-interruptive feedback group
2. They were provided with a fixed sequence of tasks within an exploratory learning environment in which they could learn fractions.
3. Different types of feedback were delivered by the wizard based on student's speech and performance. Table 2 shows some types of these feedbacks
Table 2. Examples of feedback types [2]
4. Each session lasted on average about 15 minutes
5. Participants in the low-interruptive group were able to ignore the feedback provided, by not clicking on the highlighted light bulb. In contrast, participants in the high-interruptive group had to dismiss the pop-up window before they could proceed with the task
6. At the end, participants completed a post-questionnaire with 7 questions targeted to learn their thoughts about the learning environment, especially the feedback, and if they found it interruptive
7. A smiley face scale [22] was used and scored 1 through 5 (Figure 10)
Figure 10. Smiley scale used for post questionnaire [2]
## Annotation
In the course of post-procedure, researchers annotated affective states before and after the feedback was provided. The recorded voice of students and the recorded video of screen display were analyzed independently by two researchers for this task. When two sets of annotations differed in some parts, those parts were re-analyzed and agreed upon between researchers.
They defined affective states in the annotation process as follows :
• ENJOYMENT: Engagement with the learning task. Statements like "This is fun"
• SURPRISE: Gasping. Statements like "Huh?" or "Oh, no!"
• CONFUSION: Failing to perform a particular task. Statements such as "I'm confused!" or "Why didn't it work?"
• FRUSTRATION: Tendency to give up, repeatedly clicking on objects in the learning platform or repeatedly failing to perform a particular task, sighing, statements such as, "What's going on?!".
• BOREDOM: Statements such as "Can we do something else?" or "This is boring".
## Analysis
As the data were categorical, they incorporated Chi-Square tests to investigate if there were statistically significant differences between the groups.
Students' affective states before and after feedback was given are illustrated in Figure 11 and are distinguished based on the two distinct groups. As Figure 10 implies, only three affective states of enjoyment, confusion, and frustration were identified in the course of this study. Researchers argued that the absence of the affective state of boredom could be due to the session's short time (15 minutes). They also believed that absence of the affective state of surprise could be associated with possible brief experience of surprise that they missed in the annotation process.
Analysis of post-questionnaires in this study was performed by applying Mann-Whitney test, which reported no significant differences between the two groups (Table 3).
## Findings
The findings of this study can be presented in terms of addressing the two initial research questions:
The effect of different forms of feedback presentation on students' affective states (Q1)
The findings showed (Figure 11) that, in order to improve the learning process:
• When students are enjoying the task, both high- and low-interruptive feedback is effective
• When students are confused, high-interruptive feedback should be delivered
• When students are frustrated, high-interruptive feedback should be presented, otherwise, it is very likely that they ignore the feedback
Figure 11. Students’ affective states before and after feedback was given [2]
Student's perception of the learning environment, including feedback (Q2)
The results of post-assessment are presented in Table 3 :
Table 3. Results of the post-assessment smiley questionnaire. Median (min/max) [2]
• No significant differences between groups were identified
• The researchers mentioned that the slightly better experience among the low interruptive group in the question 2 and question 6 of the post-questionnaire can be associated with the finding of a past research [23] which indicates that students rather to be able to decide themselves, when to receive help than being imposed by interruptive feedback.
The researchers concluded the study by presenting their plan for future work: development of an intelligent feedback system for learning environments to automatically select the best presentation of feedback (low- or high-interruptive) and also choose the best type of it (e.g. Problem solving support, reflective prompts, affect boosts, etc.) based on the affective states of students.
## Conclusion
The findings of Feedback study are significant as we can enhance the affective state of a student by delivering a proper type of feedback (Figure 11), and subsequently improve the student's learning process. The findings emphasize the important role of feedback presentation when students are confused or frustrated.
On the other hand, one might ask how we should detect the affective state of the students automatically in the first place to be able to tailor feedback representation based upon? Unfortunately, nothing in this regard was mentioned and it seems that researchers completely forgot to address this matter or refer curious readers to studies Predicting Affect of User's Interaction with an Intelligent Tutoring System, in which, this type of users' traits were shown to be elicited from Eye-gaze data. Another concern about this study is the fact that its subjects may not well represent the community of students as they were all in fifth grade. Therefore, although the idea behind this work can inspire researchers performing more investigations, I believe the finding can hardly be generalized.
# Annotated Bibliography
1. G. Carenini, C. Conati, E. Hoque, B. Steichen, D. Toker, and J. Enns, “Highlighting interventions and user differences: informing adaptive information visualization support,” in Proceedings of the SIGCHI Conference on Human Factors in Computing Systems. ACM, 2014, pp. 1835–1844.
2. B. Grawemeyer, W. Holmes, S. Guti ́errez-Santos, A. Hansen, K. Loibl, and M. Mavrikis, “Light-bulb moment?: Towards adaptive presentation of feedback based on students’ affective state,” in Proceedings of the 20th International Conference on Intelligent User Interfaces. ACM, 2015, pp. 400–404.
3. C. Conati, G. Carenini, D. Toker, and S. Lall ́e, “Towards user-adaptive information visualization.” in AAAI, 2015, pp. 4100–4106.
4. C. Conati and H. Maclaren, “Exploring the role of individual differences in information visualization,” in Proceedings of the working conference on Advanced visual interfaces. ACM, 2008, pp. 199–206.
5. D. Toker, C. Conati, G. Carenini, and M. Haraty, “Towards adaptive information visualization: on the influence of user characteristics,” in User Modeling, Adaptation, and Personalization. Springer, 2012, pp. 274–285.
6. M. C. Velez, D. Silver, and M. Tremaine, “Understanding visualization through spatial ability differ- ences,” in Visualization, 2005. VIS 05. IEEE. IEEE, 2005, pp. 511–518.
7. T. M. Green and B. Fisher, “Towards the personal equation of interaction: The impact of personality factors on visual analytics interface interaction,” in Visual Analytics Science and Technology (VAST), 2010 IEEE Symposium on. IEEE, 2010, pp. 203–210.
8. C. Ziemkiewicz, R. J. Crouser, A. R. Yauilla, S. L. Su, W. Ribarsky, and R. Chang, “How locus of control influences compatibility with visualization style,” in Visual Analytics Science and Technology (VAST), 2011 IEEE Conference on. IEEE, 2011, pp. 81–90.
9. B. P. Woolf, Building intelligent interactive tutors: Student-centered strategies for revolutionizing e- learning. Morgan Kaufmann, 2010.
10. A. Jameson, “Adaptive interfaces and agents,” Human-Computer Interaction: Design Issues, Solutions, and Applications, vol. 105, 2009.
11. D. Gotz and Z. Wen, “Behavior-driven visualization recommendation,” in Proceedings of the 14th international conference on Intelligent user interfaces. ACM, 2009, pp. 315–324.
12. C. Conati, E. Hoque, D. Toker, and B. Steichen, “When to adapt: Detecting user’s confusion during visualization processing.” in UMAP Workshops, 2013.
13. B. Grawemeyer and R. Cox, “Graphical data displays and database queries: Helping users select the right display for the task,” in Smart Graphics. Springer, 2005, pp. 53–64.
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15. J.-w. Ahn and P. Brusilovsky, “Adaptive visualization for exploratory information retrieval,” Informa- tion Processing & Management, vol. 49, no. 5, pp. 1139–1164, 2013.
16. L. Bartram, C. Ware, and T. Calvert, “Moticons:: detection, distraction and task,” International Journal of Human-Computer Studies, vol. 58, no. 5, pp. 515–545, 2003.
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Permission is granted to copy, distribute and/or modify this document according to the terms in Creative Commons License, Attribution-NonCommercial-ShareAlike 3.0. The full text of this license may be found here: CC by-nc-sa 3.0
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https://blog.minicircuits.com/rf-microwave-equalizers-an-essential-ingredient-for-the-modern-system-designer/
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Select Page
The need for equalization has become commonplace throughout the RF/microwave/millimeter wave frequency ranges. Modern military, satellite and wireless communications systems transmit and receive signals with relatively high instantaneous bandwidths. Gain variation across the signal bandwidth induces distortion in the transmitted or received signal because not all frequency components are amplified equally1. In other words, for multi-phase, multi-amplitude-level-modulated systems, unintended amplitude differences (i.e. due to gain changes) over the occupied bandwidth introduce errors, leading to incorrect interpretation of the signal and an increase in system bit error rate (BER)2. A 5G system, for example, may operate in FR1 (3.3-4.2 GHz) with a bandwidth of 100 MHz or in FR2 (24-54 GHz) with an aggregate contiguous bandwidth of 1.2 GHz3. 5G signals utilize quadrature amplitude modulation (QAM)4, a multi-phase, multi-amplitude-level modulation scheme that is susceptible to amplitude (gain) variation over its occupied bandwidth. Consequently, gain flatness specifications have become more demanding for receiver and transmitter chains operating across wider bandwidths.
Most transmitter and receiver systems experience decreasing gain and increasing losses at progressively higher frequencies. The equalizer is a component designed specifically to compensate for this natural tendency toward roll-off exhibited by these systems. Mini-Circuits’ equalizers extend from DC to 45 GHz. In combination with Mini-Circuits’ family of ZEQ and VEQY connectorized components, the EQY-series SMT and die devices provide the designer great latitude in the selection of an equalizer to fit any application. These equalizers are offered in many different attenuation levels and in bandwidths ranging from DC to 6 GHz, 20 GHz, 28 GHz, and 45 GHz.
## What is an Equalizer?
An equalizer, sometimes referred to as a “lossy equalizer,” is essentially an attenuator placed in a circuit or system that exhibits an insertion loss that is at its maximum at the lowest operating frequency and at its minimum at the highest operating frequency. A complementary statement is that the equalizer exhibits minimum gain at the lowest operating frequency and maximum gain at the highest operating frequency. Placing the equalizer in a system cascade “tilts” the gain response in a positive direction. The magnitude by which the equalizer tilts the system gain response from minimum to maximum operating frequency is called its equalization value or “slope.”
Although far less common, some equalizers tilt gain in a negative direction. This type of equalizer is suitable in applications requiring waveguide components, for example. Additionally, parabolic equalizers have long established a niche in the area of traveling-wave tube (TWT) amplifiers. Regardless of the shape of the equalizer response, the end goal is to flatten or “equalize” the gain of a system over a relatively wide bandwidth.
Figures 1 and 2 show frequency response curves for three SMT devices in Mini-Circuits’ line of 45 GHz equalizers, the EQY-3-453+, EQY-6-453+ and EQY-10-453+. Each equalizer in Figure 1 has a different slope, or magnitude of monotonic decrease in attenuation from DC to 45 GHz. The slope of each model may also be interpreted as the magnitude of monotonic increase in gain from DC to 45 GHz, as shown in Figure 2. It is easier to visualize how the equalizer compensates for gain roll-off when the frequency response is viewed from a gain perspective, as in Figure 2. Mini-Circuits’ family of 45 GHz equalizers includes a unique model for each 1 dB increment in slope from 3 to 10 dB. Additionally, every equalizer in the 45 GHz line is available in die form.
Figure 1: EQY-3-453+, EQY-6-453+ and EQY-10-453+ MMIC SMT equalizer IL vs. frequency.
Figure 2: EQY-3-453+, EQY-6-453+ and EQY-10-453+ MMIC SMT equalizer gain vs. frequency.
## When is an Equalizer Required?
Generally, equalizers are necessary in any wideband system in which elements of gain and insertion loss are cascaded in series. Examples of systems that require equalizers are wideband receivers and transmitters, where typically quite a number of gain and insertion loss elements are cascaded together, and where flat system frequency response is often desired. In most cases, the gain of the amplification stages declines with increasing frequency, and the insertion loss of the lossy elements increases, leading to significant roll-off in overall cascaded system gain. The equalizer provides a negative insertion loss slope to the system (less insertion loss at higher frequencies), and when chosen properly, may reduce or even eliminate frequency-dependent system gain roll-off.
## How Much Equalization is Necessary?
It is possible to determine the correct amount of equalization by examining the characteristics of the discrete system components for a small system. However, even cables, circuit board traces and the mismatch of connector transitions constitute additional losses with frequency that are difficult to predict. So in reality, it is therefore most often necessary to perform simulations on a well-modeled system to determine the correct amount of equalization. Even with precise modelling, designers often need to evaluate multiple slope values at the prototyping stage to achieve measured performance that matches the requirements. Mini-Circuits’ designer kits avail the designer of a multitude of slope values in small quantities for evaluation and prototyping, ensuring that optimum performance can be achieved in practice.
If the system consists of just a handful of components, however, it is quite possible to achieve a reasonable estimate of the required equalization using system calculations associated with simple cascade analysis, which we utilize for the following hypothetical system for illustration.
## Equalization Yields Flat Gain in a Two-Stage Wideband LNA
An example of a two-stage, 400 to 6000 MHz LNA for which equalization is required is shown in the block diagram in Figure 3 below. The aggressive performance goals for the design are:
• Frequency Range: 400-6000 MHz
• Gain: 30 dB min.
• NF: 1dB max.
• Output P1dB: +15 dBm min.
• Output IP3: +25 dBm min.
Figure 3: Two-stage 400-6000 MHz LNA block diagram.
The input stage is the Mini-Circuits TAV2-14LN+. This choice was made based on its very low noise figure (NF). When operated at Vd = 2V, this device maintains a NF of 0.69 to 0.75 dB over the 400-6000 MHz band. The TAV2-14LN+ also exhibits relatively high gain (16-22 dB) over the band of interest, although its gain slope will necessitate equalization. The amplifier for the final stage is the PHA-83W+, selected predominantly since it performs quite well in the linearity category, boasting 25 dBm OP1dB and 36 dBm OIP3 at 400 MHz and Vd = 9V. Not only do OP1dB and OIP3 of the PHA-83+ remain strong to 6000 MHz and beyond, but its total gain flatness across the 400-6000 MHz band is only ±1 dB.
In order to determine the required equalization in this example, it is first necessary to determine the frequency response of the system gain without the use of an equalizer. Since the gain is in dB, the cascaded gain is simply the sum of the gain of the two stages. Figure 4 shows that the gain without equalization exhibits a significant roll-off of 7 dB, 6 dB from the TAV2-14LN+ plus 1 dB from the PHA-83W+. The biggest contributor to negative gain slope, the TAV2-14LN+ input stage, will be equalized, and the results examined.
Figure 4: Gain and NF with and without equalization for two-stage LNA system.
The system is an LNA requiring very low NF (< 1 dB). Therefore, no attenuation should be added to the input. Integrating a single equalizer that has steep slope into the cascade is often not the best way to correct system gain roll-off. It is generally better to distribute equalization throughout the cascade. An arbitrary decision was made to split the required amount of equalization between two identical SMT equalizers, the EQY-3-63+, for which the frequency response is shown in Figure 5. The first of the two 3-dB equalizers is placed on the output of the first stage amplifier which greatly reduces its effect on overall NF (since a gain element precedes it). A collateral benefit of splitting the equalization in the LNA of Figure 3 is that the first equalizer serves as a low value attenuator, improving the interstage 50Ω match and mitigating VSWR interactions between stages.
The additional equalization needed is provided by a second EQY-3-63+ equalizer placed at the output of the final stage of the LNA. The cascaded system gain both with and without equalization is shown in Figure 4. The overall LNA with equalization has a gain vs. frequency slope that is now just slightly negative. The choice of equalization was sufficient to compensate for the vast majority of the gain roll-off for the LNA’s 400-6000 MHz operating range. Additionally, the absolute gain is just slightly lower than the design goal of 30 dB min. in the center of the band, which is a rather successful outcome, given this gain flatness was achieved over more than a decade of bandwidth.
Figure 5: EQY-3-63+ equalizer gain and insertion loss vs. frequency.
## The Equalizer and its Influence on Noise Figure
When an equalizer is introduced into a system, it is important to examine its effect on system noise figure (NF) over frequency since the equalizer is essentially a frequency-dependent attenuator. The effects of equalization on system performance parameters NF, P1dB, and IP3 can often be quite involved, particularly as the complexity of the system grows.
In the relatively simple example discussed above, it is first necessary to take the inverse log of each of the components’ respective noise figures (NF1, NF2, NF3, …(dB)) and Gains (dB) to determine individual noise factors (F1, F2, F3, …) and linear gains (G1, G2, G3, …). Next, the two-stage LNA requires Friis’ formula to cascade the respective, individual noise factors and to compute system noise factor (F). System noise factor is then converted back to system noise figure (NF) in dB. Sample calculations are shown below for cascaded system F and NF at 400 MHz, with equalization:
Fn = 10^(NFn/10) = 10(NFn/10)
F1 = 10^(0.69/10) = 1.17, F2 = 10^(3.77/10) = 2.38, F3 = 10^(2.96/10) = 1.98, F4 = 10^(3.77/10) = 2.38
Gn = 10^(Gn(dB)/10) = 10(Gn(dB)/10)
G1 = 10^(22.0/10) = 158.9, G2 = 10^(-3.77/10) = 0.42, G3 = 10^(6.59/10) = 45.6, G4 = 10^(-3.77/10) = 0.42
F = F1 + (F2 – 1)/G1 + (F3 – 1)/G1G2 + (F4 – 1)/G1G2G3 + …
F = 1.17 + (2.38 – 1)/158.9 + (1.98 – 1)/(158.9)(0.42) + (2.38 – 1)/( 158.9)(0.42)(45.6) = 1.196
NF = 10*log(F) = 10*log(1.196) = 0.78 dB
The results of these calculations for cascaded system NF are shown for the entire frequency range in Figure 4. Without the additional attenuation of the equalizers, the NF of the system is naturally lower, and with equalization it is higher. Even with equalization, however, system NF remains below 1 dB, meeting one of the key design goals for the LNA.
## LNA System Linearity Parameters: Output P1dB and Output IP3
The results of performing a cascade analysis for OP1dB and OIP3 are shown in Figure 6. Both parameters meet their respective design goals of +15 dBm and +25 dBm with a good amount of margin. Naturally, the amount of performance margin at the low end of the band (400 MHz), where the equalizer exhibits maximum attenuation, is lower than the margin at the high end of the band. This particular LNA has nearly flat gain and is capable of providing increasing OP1dB and OIP3 with frequency. Generally, most system components will exhibit a subtle roll-off in linearity with increasing frequency, making these positively-sloping linearity characteristics potentially useful were this LNA to be designed into a larger, more complex system.
Figure 6: Output P1dB and output IP3 with and without equalization for two-stage LNA system.
## Equalizers Ready for System Integration
Equalizers are an essential part of any wideband system for which flat gain response is required. Passive or “lossy” equalizers tend to reduce overall gain but may often have minimal effect on NF as shown in the two-stage LNA example. Additionally, when utilized between amplifier stages, VSWR interaction will be mitigated and 50Ω matching will improve along with gain flatness. While linearity experiences a slight reduction with equalization, it is possible to achieve increasing linearity with frequency. Mini-Circuits has over 70 unique equalizer models in stock with slope values from 1 to 15 dB and operating frequency ranges spanning DC to 45 GHz, including voltage variable equalizers.
Browse our full selection of RF / microwave equalizers >
## Related Blog Posts
Positive Gain Slope Amplifiers Compensate for Gain Roll-Off in Wideband Systems
Flattening Amplifier Gain Slope with MMIC Fixed Equalizers
## References
1. Keysight Support – VNA Help, “Why Measure Small-signal Gain and Flatness” Gain and Flatness (keysight.com)
2. Electronic Design October 10, 2013 “Understanding Error Vector Magnitude” Lou Frenzel Understanding Error Vector Magnitude | Electronic Design
3. Keysight Blogs, RF + Microwave, April 20, 2021 “What You Need to Know about Wideband Signal Analysis” Eric Hsu What You Need to Know about Wideband Signal Analysis | Keysight Blogs
4. 5G Technology World April 16, 2020 “The Basics of 5G’s modulation, OFDM Bob Witte The basics of 5G’s modulation, OFDM – 5G Technology World
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https://math.stackexchange.com/questions/3265576/associative-law-for-boolean-logic
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# Associative Law for Boolean Logic
The associative law states that for the logic formula:
$$(A \wedge B) \wedge C = A \wedge (B \wedge C)$$
$$(A \vee B) \vee C = A \vee (B \vee C)$$
I asked myself would the associative law hold for multiple operators, so I tested it out on $$(A \wedge B) \vee C$$ vs $$A \wedge (B \vee C)$$. This turned out to not be true once I did I truth table. For the first formula as long as C is true the entire thing is true even if A is not true, while for the second, A must be true in order for the logic formula to hold true.
My question is are there times when the associative law still works when I have multiple operators and not just two (e.g. $$A \wedge B \wedge C \vee D\vee E$$). How can I tell immediately whether or not the associative law is applicable? Are there operators (such as $$\downarrow$$) that work with the associative law even when I have different operators in the same formula?
• @PeterForeman : Disjunction is associative... – Eric Towers Jun 17 '19 at 17:29
Apart from conjunction and disjunction, other associative operations are the biconditional $$\leftrightarrow$$ and the exclusive-or $$\oplus$$, where $$a\oplus b$$ is defined as $$(a\land\lnot b)\lor (\lnot a\land b)$$, i.e., $$a\oplus b$$ is true if and only if exactly one of $$a$$ and $$b$$ is true. The conditional $$\rightarrow$$ is not associative.
To your broader question, I'd say it's not entirely clear what it means to say that the associative law applies to 'multiple operators': typically, it's only applied to iterations of the same operator.
In your example with $$(a\land b)\lor c$$ and $$a\land (b\lor c)$$, you can replace $$a\land b$$ with $$f(a,b)$$, and $$a\lor b$$ with $$g(a,b)$$. Your suggestion is then that associativity would require that $$g(f(a,b), c)$$ is equivalent to $$f(a, g(b,c))$$. However, it's not entirely clear that this is what associativity should mean in this context; and even if it does, you can't expect it to hold in general.
This is analogous to the situation with addition and multiplication. Both are associative by themselves. However, multiplication distributes over addition. You can't have combined associativity with both of them together. That is, for example, it is not true in general that $$(a+b)*c = a+(b*c).$$ In fact, what is true is that $$(a+b)*c = (a*c)+(b*c).$$ Same thing happens with Boolean logic $$\wedge$$ and $$\vee.$$
Associativity only holds if you have an expression with just one kind of binary operator in the expression. You can not combine two kinds of associative operators together in general, as demonstrated by the addition ($$+$$) and multiplication ($$*$$) example.
Of course, there can be special examples where you can combine operators and still have associativity. For example, suppose we define the operator $$a\circ b:=0$$ which is clearly associative (check). Then $$(a*b)\circ c = a*(b\circ c) = 0$$ for all $$a,b,c.$$
• So it's true that, in general, the associative law does not hold? Are there cases where they do hold? – BigBear Jun 17 '19 at 17:43
• @WilsonGuo: It would be more right to say that what you're calling "the associative law" is not the same as what most other people use that name about. Your (vastly extended) "associative law" does not hold in general. – hmakholm left over Monica Jun 17 '19 at 22:07
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http://sourceforge.net/p/gnuplot/bugs/1197/
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## #1197 postscript terminal: bad vertical centering of text
open
nobody
None
5
2013-06-29
2012-12-17
Ethan Merritt
No
The postscript terminal currently sets an offset used for vertical centering of text only once, in the prolog:
\vshift -<foo> def
This shift is only approximate to begin with and is not adjusted later when the current font changes.
Possible fix (quick-and-dirty): overwrite the vshift definition every time the font is changed using the same approximation used currently.
Better fix: re-write the Lshow/Rshow/Cshow commands to query the current font from inside the PostScript engine rather than using vshift.
## Discussion
The two possibilities I see for querying the current font are:
1. Use the font bounding box for centering.
This might not fit the current string.
1. Extract the metrics of all glyphs in the string.
How should the vertical centering be done? Using the lowest height, or the largest height, the median, ...?
For Latin fonts I would correct by the half of the lowest height (with respect to the base line). But I don't know if this would also fit cyrillic, japanese and other fonts.
If I find some time, I could come up with a proposal patch.
Christoph
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https://www.zbmath.org/?q=an%3A1333.76003
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×
# zbMATH — the first resource for mathematics
Mathematics of two-dimensional turbulence. (English) Zbl 1333.76003
Cambridge Tracts in Mathematics 194. Cambridge: Cambridge University Press (ISBN 978-1-107-02282-9/hbk; 978-1-139-57519-5/ebook). xvi, 320 p. (2012).
Publisher’s description: This book is dedicated to the mathematical study of two-dimensional statistical hydrodynamics and turbulence, described by the 2D Navier–Stokes system with a random force. The authors’ main goal is to justify the statistical properties of a fluid’s velocity field $$u(t,x)$$ that physicists assume in their work. They rigorously prove that $$u(t,x)$$ converges, as time grows, to a statistical equilibrium, independent of initial data. They use this to study ergodic properties of $$u(t,x)$$ – proving, in particular, that observables $$f(u(t,.))$$ satisfy the strong law of large numbers and central limit theorem. They also discuss the inviscid limit when viscosity goes to zero, normalising the force so that the energy of solutions stays constant, while their Reynolds numbers grow to infinity. They show that then the statistical equilibria converge to invariant measures of the 2D Euler equation and study these measures. The methods apply to other nonlinear PDEs perturbed by random forces.
##### MSC:
76-02 Research exposition (monographs, survey articles) pertaining to fluid mechanics 76F02 Fundamentals of turbulence 76D05 Navier-Stokes equations for incompressible viscous fluids
Full Text:
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https://www.physicsforums.com/threads/would-baryons-and-their-antiparticles-interact-via-the-strong-interaction.239730/
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# Would baryons and their antiparticles interact via the strong interaction?
1. Jun 11, 2008
### K.J.Healey
And would the potential be equal in magnitude yet opposite in sign?
If you were to approximate a yukawa potential for some baryon and had it "near" its antiparticle, what would the potential look like. The same for a baryon and another baryon but opposite?
This would just be like a residual strong interaction right? A quick approximation maybe being a light meson exchange?
Thanks!
2. Jun 11, 2008
### humanino
It took me a while to realize what was the question about ! In hadronic physics, we are not used to considering particles vs antiparticles, but more in terms of multiplets of similar particles, where it so happens that the multiplets connect particles with their antiparticles. One of the reasons QCD was quickly realized to be an excellent candidate for strong interactions is that there is an attractive force in the quark-antiquark and three-quark sectors, but repulsive in the quark-quark sector. So things are not as simple as "if you turn a particle into its antiparticle, just reverse the force". However, particles and antiparticles do interact via strong interaction.
The very notion of potential works only in non-relativistic physics, so bearing that in mind, we need to do something like fixing our baryons in static positions at a given distance from one another and the potential would be the resulting energy of the system. It may or may not be relevant to the dynamics, but we can do that. Then most likely the potential will remain essentially the same. Reason is partly answered
we would indeed have meson exchanges between our static colorless sources. The quantum numbers of those mesons will determine whether the interaction is repulsive or attractive, their mass will determine the range of static interaction. So if you take one of your baryons and change it into another one in your multiplet (like its antibaryon) you will need to exchange other mesons but they will still be in the same multiplet of mesons (not the same multiplet as your baryons). Say at short distances you will have a similar more massive vector repulsion and at long distance you will have a less massive scalar attraction (masses are almost degenerate in a given multiplet).
Last edited: Jun 11, 2008
3. Jun 11, 2008
### K.J.Healey
Well, I'm not sure how detailed I should be since I'm supposed to be researching this on my own, but I consider asking questions here part of research.
Now, some of you may have the answer right away, but that not what I want, I really want to make sure I understand this and how to go about figuring it out. Heres the scenario:
Non relativistic is fine.
I'm trying calculate an oscillation suppression of a nnbar in the presence of other neutrons via the strong interaction with a very naive model. I've read a few articles that give a decent method of approximating the residual-strong interaction between nucleons in a nucleus by using a sum of a heavy and a light meson exchange. They have all the data fitted so I have actual values for the coupling contants + masses.
While I'm not doing these calculations for nuclei, they are of the same interaction distance.
I guess I'm asking, if I have this fit of a sum of two meson exchange potentials for a neutron-neutron interaction (approx), what can I do to it (the potential) to make it reflect the interaction (approx) of a neutron-antineutron?
Is it equal in magnitude, yet opposite in sign? If so then I know what I have to do, just toss it in the Hamiltonian, and calculate he oscillation freq. {{E+V, dm},{dm,E-V}} or something similar.
Or is it completely different?
I'm trying to figure out how the strong interaction behaves for the antiparticle part of a nnbar state.
Last edited: Jun 11, 2008
4. Jun 11, 2008
### meopemuk
I also thought about this question. I found a couple of references that might be useful:
[1] M.-L. Yan, S. Li, B. Wu, B.-Q. Ma, Baryonium with a phenomenological
skyrmion-type potential. http://www.arxiv.org/abs/hep-ph/0405087v4
[2] J.M. Richard, Historical Survey of the Quasi-Nuclear Baryonium,
http://arxiv.org/abs/nucl-th/9906006v1
For example, if you change the sign of the nucleon-antinucleon potential shown in fig 1. of [1] you'll get something similar to the nucleon-nucleon potential as usually drawn in textbooks. Experimental studies of baryon-antibaryon potentials are difficult, because they tend to annihilate.
Another evidence for the opposite character of baryon-baryon and baryon-antibaryon potentials may come from the Sakata model, in which mesons are represented as nucleon-antinucleon bound states and baryons are composites of two nucleons and one antinucleon. This model was quite popular in the end of 1950's. Then it was replaced by the quark model and (almost) forgotten. In the paper
K. Matumoto, S. Sawada, Y. Sumi, M. Yonezawa, "Mass formula in the
Sakata model" Progr. Theor. Phys. Suppl. 19 (1961), 66
masses of (then known) mesons and baryons were fitted in the Sakata model, and the conclusion was that interaction energy nucleon-antinucleon has equal magnitude but opposite sign wrt the interaction energy nucleon-nucleon.
Eugene.
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