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sciq-2063
|
multiple_choice
|
The abundance of this substance in the atmosphere is what most scientist agree that is causing global warming?
|
[
"argon",
"iron oxide",
"carbon dioxide",
"liquid dioxide"
] |
C
|
Relavent Documents:
Document 0:::
Carbon is a primary component of all known life on Earth, representing approximately 45–50% of all dry biomass. Carbon compounds occur naturally in great abundance on Earth. Complex biological molecules consist of carbon atoms bonded with other elements, especially oxygen and hydrogen and frequently also nitrogen, phosphorus, and sulfur (collectively known as CHNOPS).
Because it is lightweight and relatively small in size, carbon molecules are easy for enzymes to manipulate. It is frequently assumed in astrobiology that if life exists elsewhere in the Universe, it will also be carbon-based. Critics refer to this assumption as carbon chauvinism.
Characteristics
Carbon is capable of forming a vast number of compounds, more than any other element, with almost ten million compounds described to date, and yet that number is but a fraction of the number of theoretically possible compounds under standard conditions. The enormous diversity of carbon-containing compounds, known as organic compounds, has led to a distinction between them and compounds that do not contain carbon, known as inorganic compounds. The branch of chemistry that studies organic compounds is known as organic chemistry.
Carbon is the 15th most abundant element in the Earth's crust, and the fourth most abundant element in the universe by mass, after hydrogen, helium, and oxygen. Carbon's widespread abundance, its ability to form stable bonds with numerous other elements, and its unusual ability to form polymers at the temperatures commonly encountered on Earth enables it to serve as a common element of all known living organisms. In a 2018 study, carbon was found to compose approximately 550 billion tons of all life on Earth. It is the second most abundant element in the human body by mass (about 18.5%) after oxygen.
The most important characteristics of carbon as a basis for the chemistry of life are that each carbon atom is capable of forming up to four valence bonds with other atoms simultaneously
Document 1:::
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosphere is the outer region of a star, which includes the layers above the opaque photosphere; stars of low temperature might have outer atmospheres containing compound molecules.
The atmosphere of Earth is composed of nitrogen (78 %), oxygen (21 %), argon (0.9 %), carbon dioxide (0.04 %) and trace gases. Most organisms use oxygen for respiration; lightning and bacteria perform nitrogen fixation to produce ammonia that is used to make nucleotides and amino acids; plants, algae, and cyanobacteria use carbon dioxide for photosynthesis. The layered composition of the atmosphere minimises the harmful effects of sunlight, ultraviolet radiation, solar wind, and cosmic rays to protect organisms from genetic damage. The current composition of the atmosphere of the Earth is the product of billions of years of biochemical modification of the paleoatmosphere by living organisms.
Composition
The initial gaseous composition of an atmosphere is determined by the chemistry and temperature of the local solar nebula from which a planet is formed, and the subsequent escape of some gases from the interior of the atmosphere proper. The original atmosphere of the planets originated from a rotating disc of gases, which collapsed onto itself and then divided into a series of spaced rings of gas and matter that, which later condensed to form the planets of the Solar System. The atmospheres of the planets Venus and Mars are principally composed of carbon dioxide and nitrogen, argon and oxygen.
The composition of Earth's atmosphere is determined by the by-products of the life that it sustains. Dry air (mixture of gases) from Earth's atmosphere contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and traces of hydrogen,
Document 2:::
Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature, and as the source of available carbon in the carbon cycle, atmospheric is the primary carbon source for life on Earth. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. Carbon dioxide is soluble in water and is found in groundwater, lakes, ice caps, and seawater. When carbon dioxide dissolves in water, it forms carbonate and mainly bicarbonate (), which causes ocean acidification as atmospheric levels increase.
It is a trace gas in Earth's atmosphere at 421 parts per million (ppm), or about 0.04% (as of May 2022) having risen from pre-industrial levels of 280 ppm or about 0.025%. Burning fossil fuels is the primary cause of these increased concentrations and also the primary cause of climate change.
Its concentration in Earth's pre-industrial atmosphere since late in the Precambrian was regulated by organisms and geological phenomena. Plants, algae and cyanobacteria use energy from sunlight to synthesize carbohydrates from carbon dioxide and water in a process called photosynthesis, which produces oxygen as a waste product. In turn, oxygen is consumed and is released as waste by all aerobic organisms when they metabolize organic compounds to produce energy by respiration. is released from organic materials when they decay or combust, such as in forest fires. Since plants require for photosynthesis, and humans and animals depend on plants for food, is necessary for the survival of life on earth.
Carbon dioxide is 53% more dense than dry air, but is long lived and thoroughly mixes in the atmosphere. About half of excess emissions to the atmosphere are absorbed by land and ocean carbon sinks. These sinks can become saturated and are volatile, as decay and wildfires result i
Document 3:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 4:::
An ecosphere is a planetary closed ecological system. In this global ecosystem, the various forms of energy and matter that constitute a given planet interact on a continual basis. The forces of the four Fundamental interactions cause the various forms of matter to settle into identifiable layers. These layers are referred to as component spheres with the type and extent of each component sphere varying significantly from one particular ecosphere to another. Component spheres that represent a significant portion of an ecosphere are referred to as a primary component spheres. For instance, Earth's ecosphere consists of five primary component spheres which are the Geosphere, Hydrosphere, Biosphere, Atmosphere, and Magnetosphere.
Types of component spheres
Geosphere
The layer of an ecosphere that exists at a Terrestrial planet's Center of mass and which extends radially outward until ending in a solid and spherical layer known as the Crust (geology).
This includes rocks and minerals that are present on the Earth as well as parts of soil and skeletal remains of animals that have become fossilized over the years. This is all about process how rocks metamorphosize. They go through solids to weathered to washing away and back to being buried and resurrected. The primary agent driving these processes is the movement of Earth’s tectonic plates, which creates mountains, volcanoes, and ocean basins. The inner core of the Earth contains liquid iron, which is an important factor in the geosphere as well as the magnetosphere.
Hydrosphere
The total mass of water, regardless of phase (e.g. liquid, solid, gas), that exists within an ecosphere. It's possible for the hydrosphere to be highly distributed throughout other component spheres such as the geosphere and atmosphere.
There are about 1.4 billion km of water on Earth. That includes liquid water in the ocean, lakes, and rivers. It includes frozen water in snow, ice, and glaciers, and water that’s underground in soils and rocks
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
The abundance of this substance in the atmosphere is what most scientist agree that is causing global warming?
A. argon
B. iron oxide
C. carbon dioxide
D. liquid dioxide
Answer:
|
|
sciq-6983
|
multiple_choice
|
What are different forms of the same gene?
|
[
"genomes",
"nuerons",
"peptides",
"alleles"
] |
D
|
Relavent Documents:
Document 0:::
Genetics (from Ancient Greek , “genite” and that from , “origin”), a discipline of biology, is the science of heredity and variation in living organisms.
Articles (arranged alphabetically) related to genetics include:
#
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Document 1:::
The Encyclopedia of Genetics () is a print encyclopedia of genetics edited by Sydney Brenner and Jeffrey H. Miller. It has four volumes and 1,700 entries. It is available online at http://www.sciencedirect.com/science/referenceworks/9780122270802.
Genetics
Genetics literature
Document 2:::
Major gene is a gene with pronounced phenotype expression, in contrast to a modifier gene. Major gene characterizes common expression of oligogenic series, i.e. a small number of genes that determine the same trait.
Major genes control the discontinuous or qualitative characters in contrast of minor genes or polygenes with individually small effects. Major genes segregate and may be easily subject to mendelian analysis. The gene categorization into major and minor determinants is more or less arbitrary. Both of the two types are in all probability only end points in a more or less continuous series of gene action and gene interactions.
The term major gene was introduced into the science of inheritance by Keneth Mather (1941).
See also
Gene interaction
Minor gene
Gene
Document 3:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 4:::
Alleles have identity by type (IBT) when they have the same phenotypic effect or, if applied to a variation in the composition of DNA such as a single nucleotide polymorphism, when they have the same DNA sequence.
Alleles that are identical by type fall into two groups; those that are identical by descent (IBD) because they arose from the same allele in an earlier generation; and those that are non-identical by descent (NIBD) because they arose from separate mutations. NIBD can also be identical by state (IBS) though, if they share the same mutational expression but not through a recent common ancestor. Parent-offspring pairs share 50% of their genes IBD, and monozygotic twins share 100% IBD.
See also
Population genetics
External links
https://web.archive.org/web/20060309055031/http://darwin.eeb.uconn.edu/eeb348/lecture-notes/identity.pdf
http://zwets.com/pedkin/thompson.pdf
Classical genetics
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What are different forms of the same gene?
A. genomes
B. nuerons
C. peptides
D. alleles
Answer:
|
|
sciq-4117
|
multiple_choice
|
Transparent, translucent, or opaque are properties of matter based on an interaction with what?
|
[
"electricity",
"gravity",
"light",
"air"
] |
C
|
Relavent Documents:
Document 0:::
In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable scattering of light. On a macroscopic scale (one in which the dimensions are much larger than the wavelengths of the photons in question), the photons can be said to follow Snell's law. Translucency (also called translucence or translucidity) allows light to pass through, but does not necessarily (again, on the macroscopic scale) follow Snell's law; the photons can be scattered at either of the two interfaces, or internally, where there is a change in index of refraction. In other words, a translucent material is made up of components with different indices of refraction. A transparent material is made up of components with a uniform index of refraction. Transparent materials appear clear, with the overall appearance of one color, or any combination leading up to a brilliant spectrum of every color. The opposite property of translucency is opacity. Other categories of visual appearance, related to the perception of regular or diffuse reflection and transmission of light, have been organized under the concept of cesia in an order system with three variables, including transparency, translucency and opacity among the involved aspects.
When light encounters a material, it can interact with it in several different ways. These interactions depend on the wavelength of the light and the nature of the material. Photons interact with an object by some combination of reflection, absorption and transmission.
Some materials, such as plate glass and clean water, transmit much of the light that falls on them and reflect little of it; such materials are called optically transparent. Many liquids and aqueous solutions are highly transparent. Absence of structural defects (voids, cracks, etc.) and molecular structure of most liquids are mostly responsible for excellent optical transmission.
Materials which do not
Document 1:::
A physical property is any property that is measurable, involved in the physical system, intensity on the object's state and behavior. The changes in the physical properties of a system can be used to describe its changes between momentary states. A quantifiable physical property is called physical quantity. Measurable physical quantities are often referred to as observables.
Some physical properties are qualitative, such as shininess, brittleness, etc.; some general qualitative properties admit more specific related quantitative properties, such as in opacity, hardness, ductility,viscosity, etc.
Physical properties are often characterized as intensive and extensive properties. An intensive property does not depend on the size or extent of the system, nor on the amount of matter in the object, while an extensive property shows an additive relationship. These classifications are in general only valid in cases when smaller subdivisions of the sample do not interact in some physical or chemical process when combined.
Properties may also be classified with respect to the directionality of their nature. For example, isotropic properties do not change with the direction of observation, and anisotropic properties do have spatial variance.
It may be difficult to determine whether a given property is a material property or not. Color, for example, can be seen and measured; however, what one perceives as color is really an interpretation of the reflective properties of a surface and the light used to illuminate it. In this sense, many ostensibly physical properties are called supervenient. A supervenient property is one which is actual, but is secondary to some underlying reality. This is similar to the way in which objects are supervenient on atomic structure. A cup might have the physical properties of mass, shape, color, temperature, etc., but these properties are supervenient on the underlying atomic structure, which may in turn be supervenient on an underlying quan
Document 2:::
Invisibility is the state of an object that cannot be seen. An object in this state is said to be invisible (literally, "not visible"). The phenomenon is studied by physics and perceptual psychology.
Since objects can be seen by light in the visible spectrum from a source reflecting off their surfaces and hitting the viewer's eye, the most natural form of invisibility (whether real or fictional) is an object that neither reflects nor absorbs light (that is, it allows light to pass through it). This is known as
transparency, and is seen in many naturally occurring materials (although no naturally occurring material is 100% transparent).
Invisibility perception depends on several optical and visual factors. For example, invisibility depends on the eyes of the observer and/or the instruments used. Thus an object can be classified as "invisible to" a person, animal, instrument, etc. In research on sensorial perception it has been shown that invisibility is perceived in cycles.
Invisibility is often considered to be the supreme form of camouflage, as it does not reveal to the viewer any kind of vital signs, visual effects, or any frequencies of the electromagnetic spectrum detectable to the human eye, instead making use of radio, infrared or ultraviolet wavelengths.
In illusion optics, invisibility is a special case of illusion effects: the illusion of free space.
The term is often used in fantasy and science fiction, where objects cannot be seen by means of magic or hypothetical technology.
Practical efforts
Technology can be used theoretically or practically to render real-world objects invisible.
Making use of a real-time image displayed on a wearable display, it is possible to create a see-through effect. This is known as active camouflage. Though stealth technology is declared to be invisible to radar, all officially disclosed applications of the technology can only reduce the size and/or clarity of the signature detected by radar.
In 2003 the Chilean s
Document 3:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 4:::
The visual appearance of objects is given by the way in which they reflect and transmit light. The color of objects is determined by the parts of the spectrum of (incident white) light that are reflected or transmitted without being absorbed. Additional appearance attributes are based on the directional distribution of reflected (BRDF) or transmitted light (BTDF) described by attributes like glossy, shiny versus dull, matte, clear, turbid, distinct, etc. Since "visual appearance" is a general concept that includes also various other visual phenomena, such as color, visual texture, visual perception of shape, size, etc., the specific aspects related to how humans see different spatial distributions of light (absorbed, transmitted and reflected, either regularly or diffusely) have been given the name cesia. It marks a difference (but also a relationship) with color, which could be defined as the sensation arising from different spectral compositions or distributions of light.
Appearance of reflective objects
The appearance of reflecting objects is determined by the way the surface reflects incident light. The reflective properties of the surface can be characterized by a closer look at the (micro)-topography of that surface.
Structures on the surface and the texture of the surface are determined by typical dimensions between some 10 mm and 0.1 mm (the detection limit of the human eye is at ~0.07 mm). Smaller structures and features of the surface cannot be directly detected by the unaided eye, but their effect becomes apparent in objects or images reflected in the surface. Structures at and below 0.1 mm reduce the distinctness of image (DOI), structures in the range of 0.01 mm induce haze and even smaller structures affect the gloss of the surface.
Definitiondiffusion, scattering: process by which the spatial distribution of a beam of radiation is changed in many directions when it is deviated by a surface or by a medium, without change of frequency of its monoch
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Transparent, translucent, or opaque are properties of matter based on an interaction with what?
A. electricity
B. gravity
C. light
D. air
Answer:
|
|
sciq-3995
|
multiple_choice
|
What is the most effective color in interrupting the nighttime portion of the photoperiod?
|
[
"yellow",
"red light",
"white light",
"blue light"
] |
B
|
Relavent Documents:
Document 0:::
Colored music notation is a technique used to facilitate enhanced learning in young music students by adding visual color to written musical notation. It is based upon the concept that color can affect the observer in various ways, and combines this with standard learning of basic notation.
Basis
Viewing color has been widely shown to change an individual's emotional state and stimulate neurons. The Lüscher color test observes from experiments that when individuals are required to contemplate pure red for varying lengths of time, [the experiments] have shown that this color decidedly has a stimulating effect on the nervous system; blood pressure increases, and respiration rate and heart rate both increase. Pure blue, on the other hand, has the reverse effect; observers experience a decline in blood pressure, heart rate, and breathing. Given these findings, it has been suggested that the influence of colored musical notation would be similar.
Music education
In music education, color is typically used in method books to highlight new material. Stimuli received through several senses excite more neurons in several localized areas of the cortex, thereby reinforcing the learning process and improving retention. This information has been proven by other researchers; Chute (1978) reported that "elementary students who viewed a colored version of an instructional film scored significantly higher on both immediate and delayed tests than did students who viewed a monochrome version".
Color studies
Effect on achievement
A researcher in this field, George L. Rogers is the Director of Music Education at Westfield State College. He is also the author of 25 articles in publications that include the Music Educators Journal, The Instrumentalist, and the Journal of Research in Music Education. In 1991, George L. Rogers did a study that researched the effect of color-coded notation on music achievement of elementary instrumental students. Rogers states that the color-co
Document 1:::
In visual physiology, adaptation is the ability of the retina of the eye to adjust to various levels of light. Natural night vision, or scotopic vision, is the ability to see under low-light conditions. In humans, rod cells are exclusively responsible for night vision as cone cells are only able to function at higher illumination levels. Night vision is of lower quality than day vision because it is limited in resolution and colors cannot be discerned; only shades of gray are seen. In order for humans to transition from day to night vision they must undergo a dark adaptation period of up to two hours in which each eye adjusts from a high to a low luminescence "setting", increasing sensitivity hugely, by many orders of magnitude. This adaptation period is different between rod and cone cells and results from the regeneration of photopigments to increase retinal sensitivity. Light adaptation, in contrast, works very quickly, within seconds.
Efficiency
The human eye can function from very dark to very bright levels of light; its sensing capabilities reach across nine orders of magnitude. This means that the brightest and the darkest light signal that the eye can sense are a factor of roughly 1,000,000,000 apart. However, in any given moment of time, the eye can only sense a contrast ratio of 1,000. What enables the wider reach is that the eye adapts its definition of what is black.
The eye takes approximately 20–30 minutes to fully adapt from bright sunlight to complete darkness and becomes 10,000 to 1,000,000 times more sensitive than at full daylight. In this process, the eye's perception of color changes as well (this is called the Purkinje effect). However, it takes approximately five minutes for the eye to adapt from darkness to bright sunlight. This is due to cones obtaining more sensitivity when first entering the dark for the first five minutes but the rods taking over after five or more minutes. Cone cells are able to regain maximum retinal sensitivity in 9
Document 2:::
Green Light, green light, green-light or greenlight may refer to:
Green-colored light, part of the visible spectrum
Arts, entertainment, and media
Films and television
Green Light (1937 film), starring Errol Flynn
Green Light (2002 film), a Turkish film written and directed by Faruk Aksoy
"Green Light" (Breaking Bad), a third-season episode of Breaking Bad
Greenlight, formal approval of a project to move forward
Literature
Green Light, a 1935 novel by Lloyd C. Douglas
"Green Light", the final passage of F. Scott Fitzgerald's novel The Great Gatsby
Greenlights (book), a 2020 book by Matthew McConaughey
Music
Albums
Green Light (Bonnie Raitt album), 1982
Green Light (Cliff Richard album), 1978
The Green Light, a 2009 mixtape by Bow Wow
Songs
"Green Light" (Cliff Richard song) (1979)
"Green Light" (Beyoncé song) (2006)
"Green Light" (John Legend song) (2008)
"Green Light" (Roll Deep song) (2010)
"Green Light" (Lorde song) (2017)
"Green Light" (Valery Leontiev song) (1984)
"Green Light", by the American Breed from Bend Me, Shape Me (1968)
"Green Light", by Girls' Generation from Lion Heart
"Green Light", by Hank Thompson (1954)
"Green Light", by Lil Durk from Love Songs 4 the Streets 2
"Green Light", by R. Kelly from Write Me Back
"Green Light", by Sonic Youth from Evol
"Green Light", by the Bicycles from Oh No, It's Love
"Green Lights", by Aloe Blacc (2011)
"Greenlight" (Pitbull song) (2016)
"Green Lights", by Sarah Jarosz from Undercurrent (2016)
"Green Light", by Kylie Minogue from Tension (2023)
"Greenlight", by 5 Seconds of Summer from 5 Seconds of Summer
"Greenlight", by Enisa Nikaj which represented New York in the American Song Contest
"Greenlights" (song), by Krewella
Computing and technology
Greenlight (Internet service), a fiber-optic Internet service provided by the city of Wilson, North Carolina, US
Greenlight Networks, a fiber-optic Internet service in Rochester, New York, US
Steam Greenlight, a service part of Val
Document 3:::
On the coloured light of the binary stars and some other stars of the heavens or in the original German is a treatise by Christian Doppler (1842) in which he postulated his principle that the observed frequency changes if either the source or the observer is moving, which later has been coined the Doppler effect. The original German text can be found in wikisource. The following annotated summary serves as a companion to that original.
Title
The title "" (On the coloured light of the binary stars and some other stars of the heavens - Attempt at a general theory including Bradley's theorem as an integral part) specifies the purpose: describe the hypothesis of the Doppler effect, use it to explain the colours of binary stars, and establish a relation with Bradley's stellar aberration.
Content
§ 1 In which Doppler reminds the readers that light is a wave, and that there is debate as to whether it is a transverse wave, with aether particles oscillating perpendicular to the propagation direction. Proponents claim this is necessary to explain polarised light, whereas opponents object to implications for the aether. Doppler doesn't choose sides, although the issue returns in § 6.
§ 2 Doppler observes that colour is a manifestation of the frequency of the light wave, in the eye of the beholder. He describes his principle that a frequency shift occurs when the source or the observer moves. A ship meets waves at a faster rate when sailing against the waves than when sailing along with them. The same goes for sound and light.
§ 3 Doppler derives his equations for the frequency shift, in two cases:
§ 4 Doppler provides imaginary examples of large and small frequency shifts for sound:
§ 5 Doppler provides imaginary examples of large and small frequency shifts for light from stars. Velocities are expressed in Meilen/s, and the light speed has a rounded value of 42000 Meilen/s. Doppler assumes that 458 THz (extreme red) and 727 THz (extreme violet) are the borders of the v
Document 4:::
Cosmic ray visual phenomena, or light flashes (LF), also known as Astronaut's Eye, are spontaneous flashes of light visually perceived by some astronauts outside the magnetosphere of the Earth, such as during the Apollo program. While LF may be the result of actual photons of visible light being sensed by the retina, the LF discussed here could also pertain to phosphenes, which are sensations of light produced by the activation of neurons along the visual pathway.
Possible causes
Researchers believe that the LF perceived specifically by astronauts in space are due to cosmic rays (high-energy charged particles from beyond the Earth's atmosphere), though the exact mechanism is unknown. Hypotheses include Cherenkov radiation created as the cosmic ray particles pass through the vitreous humour of the astronauts' eyes, direct interaction with the optic nerve, direct interaction with visual centres in the brain, retinal receptor stimulation, and a more general interaction of the retina with radiation.
Conditions under which the light flashes were reported
Astronauts who had recently returned from space missions to the Hubble Space Telescope, the International Space Station and Mir Space Station reported seeing the LF under different conditions. In order of decreasing frequency of reporting in a survey, they saw the LF in the dark, in dim light, in bright light and one reported that he saw them regardless of light level and light adaptation. They were seen mainly before sleeping.
Types
Some LF were reported to be clearly visible, while others were not. They manifested in different colors and shapes. How often each type was seen varied across astronauts' experiences, as evident in a survey of 59 astronauts.
Colors
On Lunar missions, astronauts almost always reported that the flashes were white, with one exception where the astronaut observed "blue with a white cast, like a blue diamond." On other space missions, astronauts reported seeing other colors such as yellow and
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What is the most effective color in interrupting the nighttime portion of the photoperiod?
A. yellow
B. red light
C. white light
D. blue light
Answer:
|
|
sciq-1915
|
multiple_choice
|
What are the most numerous and diverse biochemical compounds?
|
[
"acids",
"lipids",
"proteins",
"vitamins"
] |
C
|
Relavent Documents:
Document 0:::
This is a list of articles that describe particular biomolecules or types of biomolecules.
A
For substances with an A- or α- prefix such as
α-amylase, please see the parent page (in this case Amylase).
A23187 (Calcimycin, Calcium Ionophore)
Abamectine
Abietic acid
Acetic acid
Acetylcholine
Actin
Actinomycin D
Adenine
Adenosmeme
Adenosine diphosphate (ADP)
Adenosine monophosphate (AMP)
Adenosine triphosphate (ATP)
Adenylate cyclase
Adiponectin
Adonitol
Adrenaline, epinephrine
Adrenocorticotropic hormone (ACTH)
Aequorin
Aflatoxin
Agar
Alamethicin
Alanine
Albumins
Aldosterone
Aleurone
Alpha-amanitin
Alpha-MSH (Melaninocyte stimulating hormone)
Allantoin
Allethrin
α-Amanatin, see Alpha-amanitin
Amino acid
Amylase (also see α-amylase)
Anabolic steroid
Anandamide (ANA)
Androgen
Anethole
Angiotensinogen
Anisomycin
Antidiuretic hormone (ADH)
Anti-Müllerian hormone (AMH)
Arabinose
Arginine
Argonaute
Ascomycin
Ascorbic acid (vitamin C)
Asparagine
Aspartic acid
Asymmetric dimethylarginine
ATP synthase
Atrial-natriuretic peptide (ANP)
Auxin
Avidin
Azadirachtin A – C35H44O16
B
Bacteriocin
Beauvericin
beta-Hydroxy beta-methylbutyric acid
beta-Hydroxybutyric acid
Bicuculline
Bilirubin
Biopolymer
Biotin (Vitamin H)
Brefeldin A
Brassinolide
Brucine
Butyric acid
C
Document 1:::
Biochemistry is the study of the chemical processes in living organisms. It deals with the structure and function of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules.
Articles related to biochemistry include:
0–9
2-amino-5-phosphonovalerate - 3' end - 5' end
Document 2:::
This is a list of topics in molecular biology. See also index of biochemistry articles.
Document 3:::
The metabolome refers to the complete set of small-molecule chemicals found within a biological sample. The biological sample can be a cell, a cellular organelle, an organ, a tissue, a tissue extract, a biofluid or an entire organism. The small molecule chemicals found in a given metabolome may include both endogenous metabolites that are naturally produced by an organism (such as amino acids, organic acids, nucleic acids, fatty acids, amines, sugars, vitamins, co-factors, pigments, antibiotics, etc.) as well as exogenous chemicals (such as drugs, environmental contaminants, food additives, toxins and other xenobiotics) that are not naturally produced by an organism.
In other words, there is both an endogenous metabolome and an exogenous metabolome. The endogenous metabolome can be further subdivided to include a "primary" and a "secondary" metabolome (particularly when referring to plant or microbial metabolomes). A primary metabolite is directly involved in the normal growth, development, and reproduction. A secondary metabolite is not directly involved in those processes, but usually has important ecological function. Secondary metabolites may include pigments, antibiotics or waste products derived from partially metabolized xenobiotics. The study of the metabolome is called metabolomics.
Origins
The word metabolome appears to be a blending of the words "metabolite" and "chromosome". It was constructed to imply that metabolites are indirectly encoded by genes or act on genes and gene products. The term "metabolome" was first used in 1998 and was likely coined to match with existing biological terms referring to the complete set of genes (the genome), the complete set of proteins (the proteome) and the complete set of transcripts (the transcriptome). The first book on metabolomics was published in 2003. The first journal dedicated to metabolomics (titled simply "Metabolomics") was launched in 2005 and is currently edited by Prof. Roy Goodacre. Some of the m
Document 4:::
Biochemical engineering, also known as bioprocess engineering, is a field of study with roots stemming from chemical engineering and biological engineering. It mainly deals with the design, construction, and advancement of unit processes that involve biological organisms (such as fermentation) or organic molecules (often enzymes) and has various applications in areas of interest such as biofuels, food, pharmaceuticals, biotechnology, and water treatment processes. The role of a biochemical engineer is to take findings developed by biologists and chemists in a laboratory and translate that to a large-scale manufacturing process.
History
For hundreds of years, humans have made use of the chemical reactions of biological organisms in order to create goods. In the mid-1800s, Louis Pasteur was one of the first people to look into the role of these organisms when he researched fermentation. His work also contributed to the use of pasteurization, which is still used to this day. By the early 1900s, the use of microorganisms had expanded, and was used to make industrial products. Up to this point, biochemical engineering hadn't developed as a field yet. It wasn't until 1928 when Alexander Fleming discovered penicillin that the field of biochemical engineering was established. After this discovery, samples were gathered from around the world in order to continue research into the characteristics of microbes from places such as soils, gardens, forests, rivers, and streams. Today, biochemical engineers can be found working in a variety of industries, from food to pharmaceuticals. This is due to the increasing need for efficiency and production which requires knowledge of how biological systems and chemical reactions interact with each other and how they can be used to meet these needs.
Education
Biochemical engineering is not a major offered by most universities and is instead an area of interest under the chemical engineering major in most cases. The following universiti
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What are the most numerous and diverse biochemical compounds?
A. acids
B. lipids
C. proteins
D. vitamins
Answer:
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|
sciq-6380
|
multiple_choice
|
Each kidney is supplied by a renal artery and what else?
|
[
"brain vein",
"spinal cord",
"renal vein",
"coronary artery"
] |
C
|
Relavent Documents:
Document 0:::
The renal circulation supplies the blood to the kidneys via the renal arteries, left and right, which branch directly from the abdominal aorta. Despite their relatively small size, the kidneys receive approximately 20% of the cardiac output.
Each renal artery branches into segmental arteries, dividing further into interlobar arteries, which penetrate the renal capsule and extend through the renal columns between the renal pyramids. The interlobar arteries then supply blood to the arcuate arteries that run through the boundary of the cortex and the medulla. Each arcuate artery supplies several interlobular arteries that feed into the afferent arterioles that supply the glomeruli.
After filtration occurs, the blood moves through a small network of venules that converge into interlobular veins. As with the arteriole distribution, the veins follow the same pattern: the interlobular provide blood to the arcuate veins then back to the interlobar veins, which come to form the renal vein exiting the kidney for transfusion for blood.
Structure
Arterial system
The table below shows the path that blood takes when it travels through the glomerulus, traveling "down" the arteries and "up" the veins. However, this model is greatly simplified for clarity and symmetry. Some of the other paths and complications are described at the bottom of the table. The interlobar artery and vein (not to be confused with interlobular) are between two renal lobes, also known as the renal column (cortex region between two pyramids).
Note 1: The renal artery also provides a branch to the inferior suprarenal artery to supply the adrenal gland.
Note 2: Also called the cortical radiate arteries. The interlobular artery also supplies to the stellate veins.
Note 3: The efferent arterioles do not directly drain into the interlobular vein, but rather they go to the peritubular capillaries first. The efferent arterioles of the juxtamedullary nephron drain into the vasa recta.
Segmental arteries
The
Document 1:::
The renal arteries are paired arteries that supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle.
The renal arteries carry a large portion of total blood flow to the kidneys. Up to a third of total cardiac output can pass through the renal arteries to be filtered by the kidneys.
Structure
The renal arteries normally arise at a 90° angle off of the left interior side of the abdominal aorta, immediately below the superior mesenteric artery. They have a radius of approximately 0.25 cm, 0.26 cm at the root. The measured mean diameter can differ depending on the imaging method used. For example, the diameter was found to be 5.04 ± 0.74 mm using ultrasound but 5.68 ± 1.19 mm using angiography.
Due to the anatomical position of the aorta, the inferior vena cava, and the kidneys, the right renal artery is normally longer than the left renal artery.
The right passes behind the inferior vena cava, the right renal vein, the head of the pancreas, and the descending part of the duodenum. It’s somewhat lower than the left one.
Left artery lies behind the left renal vein, the body of the pancreas and the splenic vein, and is crossed by the inferior mesenteric vein.
Branches
Before reaching the hilus of the kidney, each artery divides into four or five branches. The anterior branches (the upper, middle, lower and apical segmental arteries) lie between the renal vein and ureter, the vein being in front, the ureter behind. The posterior branches, which are fewer in number and include the posterior segmental artery, are usually situated behind the ureter.
Each vessel gives off some small inferior suprarenal branches to the suprarenal gland, the ureter, and the surrounding cellular tissue and muscles.
One or two accessory renal arteries are frequently found, especially on the left side since they usually arise from the aorta, and may come off above (more common) or below the main artery. Instead of entering the ki
Document 2:::
The vasa recta of the kidney, (vasa recta renis) are the straight arterioles, and the straight venules of the kidney, – a series of blood vessels in the blood supply of the kidney that enter the medulla as the straight arterioles, and leave the medulla to ascend to the cortex as the straight venules. (Latin: vās, "vessel"; rēctus, "straight"). They lie parallel to the loop of Henle.
These vessels branch off the efferent arterioles of juxtamedullary nephrons (those nephrons closest to the medulla). They enter the medulla, and surround the loop of Henle. Whereas the peritubular capillaries surround the cortical parts of the tubules, the vasa recta go into the medulla and are closer to the loop of Henle, and leave to ascend to the cortex.
Terminations of the vasa recta form the straight venules, branches from the plexuses at the apices of the medullary pyramids. They run outward in a straight course between the tubes of the medullary substance and join the interlobular veins to form venous arcades. These in turn unite and form veins which pass along the sides of the renal pyramids. The descending vasa recta have a non-fenestrated endothelium that contains a facilitated transport for urea; the ascending vasa recta have, on the other hand, a fenestrated endothelium.
Structure
Microanatomy
On a histological slide, the straight arterioles can be distinguished from the tubules of the loop of Henle by the presence of blood.
Function
Each straight arteriole has a hairpin turn in the medulla and carries blood at a very slow rate – two factors crucial in the maintenance of countercurrent exchange that prevent washout of the concentration gradients established in the renal medulla.
The maintenance of this concentration gradient is one of the components responsible for the kidney's ability to produce concentrated urine.
On the descending portion of the vasa recta, sodium, chloride and urea are reabsorbed into the blood, while water is secreted. On the ascending portion, so
Document 3:::
Cortical radial arteries, formerly known as interlobular arteries, are renal blood vessels given off at right angles from the side of the arcuate arteries looking toward the cortical substance. The interlobular arteries pass directly outward between the medullary rays to reach the fibrous tunic, where they end in the capillary network of this part.
These vessels do not anastomose with each other, but form end-arteries.
In their outward course, they give off lateral branches, which are the afferent arterioles that supply the renal corpuscles. The afferent arterioles, then, enter Bowman's capsule and end in the glomerulus.
From each glomerulus, the corresponding efferent arteriole arises and then exits the capsule near the point where the afferent arteriole enters. Distally, efferent arterioles branch out to form dense plexuses (i.e., capillary beds) around their adjacent renal tubules. For cortical nephrons, a single network of capillaries, known as the peritubular capillaries, surrounds the entire renal tubule, whereas for juxtamedullary nephrons, the peritubular capillaries surround only the proximal and distal convoluted tubules, while another network branching from the efferent arteriole, known as the straight arterioles of kidney, surrounds the nephron loop (of Henle).
Name
Lote refers to them as "cortical radial arteries (formerly called inter-lobular arteries)"
Mescher et al refer to them as "interlobular arteries (or cortical radial arteries)"
Document 4:::
The interlobar arteries are vessels of the renal circulation which supply the renal lobes. The interlobar arteries branch from the lobar arteries which branch from the segmental arteries, from the renal artery. They give rise to arcuate arteries.
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Each kidney is supplied by a renal artery and what else?
A. brain vein
B. spinal cord
C. renal vein
D. coronary artery
Answer:
|
|
sciq-6074
|
multiple_choice
|
What is the lipid-rich sheath that surrounds the axon and facilitates the transmission of electrical signals along the axon?
|
[
"neural sheath",
"axon sheath",
"myelin sheath",
"receptors sheath"
] |
C
|
Relavent Documents:
Document 0:::
In neurobiology, a mesaxon is a pair of parallel plasma membranes of a Schwann cell. It marks the point of edge-to-edge contact by the Schwann cell encircling the axon. A single Schwann cell of the peripheral nervous system will wrap around and support only one individual axon (then myelinated; ratio of 1:1), while the oligodendrocytes found in the central nervous system can wrap around and support 5-8 axons. Thin unmyelinated axons are often bundled, with several unmyelinated axons to a single mesaxon (and several such groups to a single Schwann cell).
The outer mesaxon (Terminologia histologica: Mesaxon externum) is the connection of the outer cell membrane to the compact myelin sheath. The inner mesaxon (Terminologia histologica: Mesaxon internum) is the connection between the myelin sheath and the inner part of the cell membrane of the Schwann cell, which is directly opposite the axolemma, i.e. the cell membrane of the nerve fibre ensheathed by the Schwann cell.
Document 1:::
Axonal transport, also called axoplasmic transport or axoplasmic flow, is a cellular process responsible for movement of mitochondria, lipids, synaptic vesicles, proteins, and other organelles to and from a neuron's cell body, through the cytoplasm of its axon called the axoplasm. Since some axons are on the order of meters long, neurons cannot rely on diffusion to carry products of the nucleus and organelles to the end of their axons. Axonal transport is also responsible for moving molecules destined for degradation from the axon back to the cell body, where they are broken down by lysosomes.
Movement toward the cell body is called retrograde transport and movement toward the synapse is called anterograde transport.
Mechanism
The vast majority of axonal proteins are synthesized in the neuronal cell body and transported along axons. Some mRNA translation has been demonstrated within axons. Axonal transport occurs throughout the life of a neuron and is essential to its growth and survival. Microtubules (made of tubulin) run along the length of the axon and provide the main cytoskeletal "tracks" for transportation. Kinesin and dynein are motor proteins that move cargoes in the anterograde (forwards from the soma to the axon tip) and retrograde (backwards to the soma (cell body)) directions, respectively. Motor proteins bind and transport several different cargoes including mitochondria, cytoskeletal polymers, autophagosomes, and synaptic vesicles containing neurotransmitters.
Axonal transport can be fast or slow, and anterograde (away from the cell body) or retrograde (conveys materials from axon to cell body).
Fast and slow transport
Vesicular cargoes move relatively fast (50–400 mm/day) whereas transport of soluble (cytosolic) and cytoskeletal proteins takes much longer (moving at less than 8 mm/day). The basic mechanism of fast axonal transport has been understood for decades but the mechanism of slow axonal transport is only recently becoming clear, as a resul
Document 2:::
A central or intermediate group of three or four large glands is imbedded in the adipose tissue near the base of the axilla.
Its afferent lymphatic vessels are the efferent vessels of all the preceding groups of axillary glands; its efferents pass to the subclavicular group.
Additional images
Document 3:::
H2.00.04.4.01001: Lymphoid tissue
H2.00.05.0.00001: Muscle tissue
H2.00.05.1.00001: Smooth muscle tissue
H2.00.05.2.00001: Striated muscle tissue
H2.00.06.0.00001: Nerve tissue
H2.00.06.1.00001: Neuron
H2.00.06.2.00001: Synapse
H2.00.06.2.00001: Neuroglia
h3.01: Bones
h3.02: Joints
h3.03: Muscles
h3.04: Alimentary system
h3.05: Respiratory system
h3.06: Urinary system
h3.07: Genital system
h3.08:
Document 4:::
A motor nerve is a nerve that transmits motor signals from the central nervous system (CNS) to the muscles of the body. This is different from the motor neuron, which includes a cell body and branching of dendrites, while the nerve is made up of a bundle of axons. Motor nerves act as efferent nerves which carry information out from the CNS to muscles, as opposed to afferent nerves (also called sensory nerves), which transfer signals from sensory receptors in the periphery to the CNS. Efferent nerves can also connect to glands or other organs/issues instead of muscles (and so motor nerves are not equivalent to efferent nerves). In addition, there are nerves that serve as both sensory and motor nerves called mixed nerves.
Structure and function
Motor nerve fibers transduce signals from the CNS to peripheral neurons of proximal muscle tissue. Motor nerve axon terminals innervate skeletal and smooth muscle, as they are heavily involved in muscle control. Motor nerves tend to be rich in acetylcholine vesicles because the motor nerve, a bundle of motor nerve axons that deliver motor signals and signal for movement and motor control. Calcium vesicles reside in the axon terminals of the motor nerve bundles. The high calcium concentration outside of presynaptic motor nerves increases the size of end-plate potentials (EPPs).
Protective tissues
Within motor nerves, each axon is wrapped by the endoneurium, which is a layer of connective tissue that surrounds the myelin sheath. Bundles of axons are called fascicles, which are wrapped in perineurium. All of the fascicles wrapped in the perineurium are wound together and wrapped by a final layer of connective tissue known as the epineurium. These protective tissues defend nerves from injury, pathogens and help to maintain nerve function. Layers of connective tissue maintain the rate at which nerves conduct action potentials.
Spinal cord exit
Most motor pathways originate in the motor cortex of the brain. Signals run down th
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What is the lipid-rich sheath that surrounds the axon and facilitates the transmission of electrical signals along the axon?
A. neural sheath
B. axon sheath
C. myelin sheath
D. receptors sheath
Answer:
|
|
sciq-2526
|
multiple_choice
|
Elements that specifically are noted to have properties of both metals and nonmetals are known as what?
|
[
"alkali metals",
"compund metals",
"metalloids",
"alloys"
] |
C
|
Relavent Documents:
Document 0:::
Nonmetals show more variability in their properties than do metals. Metalloids are included here since they behave predominately as chemically weak nonmetals.
Physically, they nearly all exist as diatomic or monatomic gases, or polyatomic solids having more substantial (open-packed) forms and relatively small atomic radii, unlike metals, which are nearly all solid and close-packed, and mostly have larger atomic radii. If solid, they have a submetallic appearance (with the exception of sulfur) and are brittle, as opposed to metals, which are lustrous, and generally ductile or malleable; they usually have lower densities than metals; are mostly poorer conductors of heat and electricity; and tend to have significantly lower melting points and boiling points than those of most metals.
Chemically, the nonmetals mostly have higher ionisation energies, higher electron affinities (nitrogen and the noble gases have negative electron affinities) and higher electronegativity values than metals noting that, in general, the higher an element's ionisation energy, electron affinity, and electronegativity, the more nonmetallic that element is. Nonmetals, including (to a limited extent) xenon and probably radon, usually exist as anions or oxyanions in aqueous solution; they generally form ionic or covalent compounds when combined with metals (unlike metals, which mostly form alloys with other metals); and have acidic oxides whereas the common oxides of nearly all metals are basic.
Properties
Abbreviations used in this section are: AR Allred-Rochow; CN coordination number; and MH Moh's hardness
Group 1
Hydrogen is a colourless, odourless, and comparatively unreactive diatomic gas with a density of 8.988 × 10−5 g/cm3 and is about 14 times lighter than air. It condenses to a colourless liquid −252.879 °C and freezes into an ice- or snow-like solid at −259.16 °C. The solid form has a hexagonal crystalline structure and is soft and easily crushed. Hydrogen is an insulator in all of
Document 1:::
A nonmetal is a chemical element that mostly lacks metallic properties. Seventeen elements are generally considered nonmetals, though some authors recognize more or fewer depending on the properties considered most representative of metallic or nonmetallic character. Some borderline elements further complicate the situation.
Nonmetals tend to have low density and high electronegativity (the ability of an atom in a molecule to attract electrons to itself). They range from colorless gases like hydrogen to shiny solids like the graphite form of carbon. Nonmetals are often poor conductors of heat and electricity, and when solid tend to be brittle or crumbly. In contrast, metals are good conductors and most are pliable. While compounds of metals tend to be basic, those of nonmetals tend to be acidic.
The two lightest nonmetals, hydrogen and helium, together make up about 98% of the observable ordinary matter in the universe by mass. Five nonmetallic elements—hydrogen, carbon, nitrogen, oxygen, and silicon—make up the overwhelming majority of the Earth's crust, atmosphere, oceans and biosphere.
The distinct properties of nonmetallic elements allow for specific uses that metals often cannot achieve. Elements like hydrogen, oxygen, carbon, and nitrogen are essential building blocks for life itself. Moreover, nonmetallic elements are integral to industries such as electronics, energy storage, agriculture, and chemical production.
Most nonmetallic elements were not identified until the 18th and 19th centuries. While a distinction between metals and other minerals had existed since antiquity, a basic classification of chemical elements as metallic or nonmetallic emerged only in the late 18th century. Since then nigh on two dozen properties have been suggested as single criteria for distinguishing nonmetals from metals.
Definition and applicable elements
Properties mentioned hereafter refer to the elements in their most stable forms in ambient conditions unless otherwise
Document 2:::
can be broadly divided into metals, metalloids, and nonmetals according to their shared physical and chemical properties. All metals have a shiny appearance (at least when freshly polished); are good conductors of heat and electricity; form alloys with other metals; and have at least one basic oxide. Metalloids are metallic-looking brittle solids that are either semiconductors or exist in semiconducting forms, and have amphoteric or weakly acidic oxides. Typical nonmetals have a dull, coloured or colourless appearance; are brittle when solid; are poor conductors of heat and electricity; and have acidic oxides. Most or some elements in each category share a range of other properties; a few elements have properties that are either anomalous given their category, or otherwise extraordinary.
Properties
Metals
Metals appear lustrous (beneath any patina); form mixtures (alloys) when combined with other metals; tend to lose or share electrons when they react with other substances; and each forms at least one predominantly basic oxide.
Most metals are silvery looking, high density, relatively soft and easily deformed solids with good electrical and thermal conductivity, closely packed structures, low ionisation energies and electronegativities, and are found naturally in combined states.
Some metals appear coloured (Cu, Cs, Au), have low densities (e.g. Be, Al) or very high melting points (e.g. W, Nb), are liquids at or near room temperature (e.g. Hg, Ga), are brittle (e.g. Os, Bi), not easily machined (e.g. Ti, Re), or are noble (hard to oxidise, e.g. Au, Pt), or have nonmetallic structures (Mn and Ga are structurally analogous to, respectively, white P and I).
Metals comprise the large majority of the elements, and can be subdivided into several different categories. From left to right in the periodic table, these categories include the highly reactive alkali metals; the less-reactive alkaline earth metals, lanthanides, and radioactive actinides; the archetypal tran
Document 3:::
A metalloid is a type of chemical element which has a preponderance of properties in between, or that are a mixture of, those of metals and nonmetals. There is no standard definition of a metalloid and no complete agreement on which elements are metalloids. Despite the lack of specificity, the term remains in use in the literature of chemistry.
The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony and tellurium. Five elements are less frequently so classified: carbon, aluminium, selenium, polonium and astatine. On a standard periodic table, all eleven elements are in a diagonal region of the p-block extending from boron at the upper left to astatine at lower right. Some periodic tables include a dividing line between metals and nonmetals, and the metalloids may be found close to this line.
Typical metalloids have a metallic appearance, but they are brittle and only fair conductors of electricity. Chemically, they behave mostly as nonmetals. They can form alloys with metals. Most of their other physical properties and chemical properties are intermediate in nature. Metalloids are usually too brittle to have any structural uses. They and their compounds are used in alloys, biological agents, catalysts, flame retardants, glasses, optical storage and optoelectronics, pyrotechnics, semiconductors, and electronics.
The electrical properties of silicon and germanium enabled the establishment of the semiconductor industry in the 1950s and the development of solid-state electronics from the early 1960s.
The term metalloid originally referred to nonmetals. Its more recent meaning, as a category of elements with intermediate or hybrid properties, became widespread in 1940–1960. Metalloids are sometimes called semimetals, a practice that has been discouraged, as the term semimetal has a different meaning in physics than in chemistry. In physics, it refers to a specific kind of electronic band structure of a substance. In this context, only
Document 4:::
An aluminide is a compound that has aluminium with other elements. Since aluminium is near the nonmetals on the periodic table, it can bond with metals differently from other metals. The properties of an aluminide are between those of a metal alloy and those of an ionic compound.
Examples
Magnesium aluminide, MgAl
Titanium aluminide, TiAl
Iron aluminides, including Fe3Al and FeAl
Nickel aluminide, Ni3Al
See category for a list.
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Elements that specifically are noted to have properties of both metals and nonmetals are known as what?
A. alkali metals
B. compund metals
C. metalloids
D. alloys
Answer:
|
|
sciq-7849
|
multiple_choice
|
What is another term for all eukaryotic organisms that are neither animals, nor plants, nor fungi?
|
[
"arthropods",
"protists",
"paramecium",
"prokaryotes"
] |
B
|
Relavent Documents:
Document 0:::
Endoparasites
Protozoan organisms
Helminths (worms)
Helminth organisms (also called helminths or intestinal worms) include:
Tapeworms
Flukes
Roundworms
Other organisms
Ectoparasites
Document 1:::
The eukaryotes () constitute the domain of Eukarya, organisms whose cells have a membrane-bound nucleus. All animals, plants, fungi, and many unicellular organisms are eukaryotes. They constitute a major group of life forms alongside the two groups of prokaryotes: the Bacteria and the Archaea. Eukaryotes represent a small minority of the number of organisms, but due to their generally much larger size, their collective global biomass is much larger than that of prokaryotes.
The eukaryotes seemingly emerged in the Archaea, within the Asgard archaea. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among the Archaea. Eukaryotes emerged approximately 2.2 billion years ago, during the Proterozoic eon, likely as flagellated cells. The leading evolutionary theory is they were created by symbiogenesis between an anaerobic Asgard archaean and an aerobic proteobacterium, which formed the mitochondria. A second episode of symbiogenesis with a cyanobacterium created the plants, with chloroplasts. The oldest-known eukaryote fossils, multicellular planktonic organisms belonging to the Gabonionta, were discovered in Gabon in 2023, dating back to 2.1 billion years ago.
Eukaryotic cells contain membrane-bound organelles such as the nucleus, the endoplasmic reticulum, and the Golgi apparatus. Eukaryotes may be either unicellular or multicellular. In comparison, prokaryotes are typically unicellular. Unicellular eukaryotes are sometimes called protists. Eukaryotes can reproduce both asexually through mitosis and sexually through meiosis and gamete fusion (fertilization).
Diversity
Eukaryotes are organisms that range from microscopic single cells, such as picozoans under 3 micrometres across, to animals like the blue whale, weighing up to 190 tonnes and measuring up to long, or plants like the coast redwood, up to tall. Many eukaryotes are unicellular; the informal grouping called protists includes many of these, with some
Document 2:::
Marine protists are defined by their habitat as protists that live in marine environments, that is, in the saltwater of seas or oceans or the brackish water of coastal estuaries. Life originated as marine single-celled prokaryotes (bacteria and archaea) and later evolved into more complex eukaryotes. Eukaryotes are the more developed life forms known as plants, animals, fungi and protists. Protists are the eukaryotes that cannot be classified as plants, fungi or animals. They are mostly single-celled and microscopic. The term protist came into use historically as a term of convenience for eukaryotes that cannot be strictly classified as plants, animals or fungi. They are not a part of modern cladistics because they are paraphyletic (lacking a common ancestor for all descendants).
Most protists are too small to be seen with the naked eye. They are highly diverse organisms currently organised into 18 phyla, but not easy to classify. Studies have shown high protist diversity exists in oceans, deep sea-vents and river sediments, suggesting large numbers of eukaryotic microbial communities have yet to be discovered. There has been little research on mixotrophic protists, but recent studies in marine environments found mixotrophic protists contribute a significant part of the protist biomass. Since protists are eukaryotes (and not prokaryotes) they possess within their cell at least one nucleus, as well as organelles such as mitochondria and Golgi bodies. Many protist species can switch between asexual reproduction and sexual reproduction involving meiosis and fertilization.
In contrast to the cells of prokaryotes, the cells of eukaryotes are highly organised. Plants, animals and fungi are usually multi-celled and are typically macroscopic. Most protists are single-celled and microscopic. But there are exceptions. Some single-celled marine protists are macroscopic. Some marine slime molds have unique life cycles that involve switching between unicellular, colonial, and
Document 3:::
Clade
The group includes eukaryotic cells that, for the most part, have a single emergent flagellum, or are amoebae with no flagella. The unikonts include opisthokonts (animals, fungi, and related forms) and Amoebozoa. By contrast, other well-known eukaryotic groups, which more often have two emergent flage
Document 4:::
Eutelic organisms have a fixed number of somatic cells when they reach maturity, the exact number being relatively constant for any one species. This phenomenon is also referred to as cell constancy. Development proceeds by cell division until maturity; further growth occurs via cell enlargement only. This growth is known as auxetic growth. It is shown by members of phylum Aschelminthes. In some cases, individual organs show eutelic properties while the organism itself does not.
Background
In 1909, Eric Martini coined the term eutely to describe the idea of cell constancy and to introduce a term literature sources would be able to use to identify organisms with a fixed amount and arrangement of cells and tissues. Since the introduction of eutely in the early 1900s, textbooks and theories of cytology and ontogeny have not used the term consistently. Advancements in the field of eutely has been developed by morphologists.
Studying of eutelic organisms has proved challenging, as most eutelic organisms are microscopic. Additionally, there is potential for mistakes in cell counting (often completed via an automated cell counter) and observation when larger organisms have numerous cells. In organisms of small size, errors in the examination and explanation of units may entirely negate reconstructions and deductions. Therefore, investigation of most eutelic organisms is done with intense scrutiny and review.
There are two distinct classes of organisms which display eutely:
Eutelic organisms whose somatic cells show a fixed, or complete pattern of cell and tissue number and arrangement
Eutelic organisms whose somatic cells show a limited, or incomplete pattern of cell and tissue number and arrangement
Examples
Eutely has been confirmed to certain degrees in various forms of diversity and sections of the tree of life. Examples include rotifers, many species of nematodes (including ascaris and the organism Caenorhabditis elegans whose male individuals have 1,033 cell
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What is another term for all eukaryotic organisms that are neither animals, nor plants, nor fungi?
A. arthropods
B. protists
C. paramecium
D. prokaryotes
Answer:
|
|
sciq-5257
|
multiple_choice
|
The duodenum is the first and the shortest part of what, and is where most chemical digestion takes place?
|
[
"rectum",
"stomach",
"large intestine",
"small intestine"
] |
D
|
Relavent Documents:
Document 0:::
Digestion is the breakdown of large insoluble food compounds into small water-soluble components so that they can be absorbed into the blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion. The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. Mechanical digestion takes place in the mouth through mastication and in the small intestine through segmentation contractions. In chemical digestion, enzymes break down food into the small compounds that the body can use.
In the human digestive system, food enters the mouth and mechanical digestion of the food starts by the action of mastication (chewing), a form of mechanical digestion, and the wetting contact of saliva. Saliva, a liquid secreted by the salivary glands, contains salivary amylase, an enzyme which starts the digestion of starch in the food; the saliva also contains mucus, which lubricates the food, and hydrogen carbonate, which provides the ideal conditions of pH (alkaline) for amylase to work, and electrolytes (Na+, K+, Cl−, HCO−3). About 30% of starch is hydrolyzed into disaccharide in the oral cavity (mouth). After undergoing mastication and starch digestion, the food will be in the form of a small, round slurry mass called a bolus. It will then travel down the esophagus and into the stomach by the action of peristalsis. Gastric juice in the stomach starts protein digestion. Gastric juice mainly contains hydrochloric acid and pepsin. In infants and toddlers, gastric juice also contains rennin to digest milk proteins. As the first two chemicals may damage the stomach wall, mucus and bicarbonates are secreted by the stomach. They provide a slimy layer that acts as a shield against the damag
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The large intestine, also known as the large bowel, is the last part of the gastrointestinal tract and of the digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces before being removed by defecation. The colon is the longest portion of the large intestine, and the terms are often used interchangeably but most sources define the large intestine as the combination of the cecum, colon, rectum, and anal canal. Some other sources exclude the anal canal.
In humans, the large intestine begins in the right iliac region of the pelvis, just at or below the waist, where it is joined to the end of the small intestine at the cecum, via the ileocecal valve. It then continues as the colon ascending the abdomen, across the width of the abdominal cavity as the transverse colon, and then descending to the rectum and its endpoint at the anal canal. Overall, in humans, the large intestine is about long, which is about one-fifth of the whole length of the human gastrointestinal tract.
Structure
The colon of the large intestine is the last part of the digestive system. It has a segmented appearance due to a series of saccules called haustra. It extracts water and salt from solid wastes before they are eliminated from the body and is the site in which the fermentation of unabsorbed material by the gut microbiota occurs. Unlike the small intestine, the colon does not play a major role in absorption of foods and nutrients. About 1.5 litres or 45 ounces of water arrives in the colon each day.
The colon is the longest part of the large intestine and its average length in the adult human is 65 inches or 166 cm (range of 80 to 313 cm) for males, and 61 inches or 155 cm (range of 80 to 214 cm) for females.
Sections
In mammals, the large intestine consists of the cecum (including the appendix), colon (the longest part), rectum, and anal canal.
The four sections of the colon are: the ascending colon, transverse colon, desce
Document 2:::
The gastrointestinal wall of the gastrointestinal tract is made up of four layers of specialised tissue. From the inner cavity of the gut (the lumen) outwards, these are:
Mucosa
Submucosa
Muscular layer
Serosa or adventitia
The mucosa is the innermost layer of the gastrointestinal tract. It surrounds the lumen of the tract and comes into direct contact with digested food (chyme). The mucosa itself is made up of three layers: the epithelium, where most digestive, absorptive and secretory processes occur; the lamina propria, a layer of connective tissue, and the muscularis mucosae, a thin layer of smooth muscle.
The submucosa contains nerves including the submucous plexus (also called Meissner's plexus), blood vessels and elastic fibres with collagen, that stretches with increased capacity but maintains the shape of the intestine.
The muscular layer surrounds the submucosa. It comprises layers of smooth muscle in longitudinal and circular orientation that also helps with continued bowel movements (peristalsis) and the movement of digested material out of and along the gut. In between the two layers of muscle lies the myenteric plexus (also called Auerbach's plexus).
The serosa/adventitia are the final layers. These are made up of loose connective tissue and coated in mucus so as to prevent any friction damage from the intestine rubbing against other tissue. The serosa is present if the tissue is within the peritoneum, and the adventitia if the tissue is retroperitoneal.
Structure
When viewed under the microscope, the gastrointestinal wall has a consistent general form, but with certain parts differing along its course.
Mucosa
The mucosa is the innermost layer of the gastrointestinal tract. It surrounds the cavity (lumen) of the tract and comes into direct contact with digested food (chyme). The mucosa is made up of three layers:
The epithelium is the innermost layer. It is where most digestive, absorptive and secretory processes occur.
The lamina propr
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The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the pancreatic duct to aid in digestion. The small intestine is about long and folds many times to fit in the abdomen. Although it is longer than the large intestine, it is called the small intestine because it is narrower in diameter.
The small intestine has three distinct regions – the duodenum, jejunum, and ileum. The duodenum, the shortest, is where preparation for absorption through small finger-like protrusions called villi begins. The jejunum is specialized for the absorption through its lining by enterocytes: small nutrient particles which have been previously digested by enzymes in the duodenum. The main function of the ileum is to absorb vitamin B12, bile salts, and whatever products of digestion that were not absorbed by the jejunum.
Structure
Size
The length of the small intestine can vary greatly, from as short as to as long as , also depending on the measuring technique used. The typical length in a living person is . The length depends both on how tall the person is and how the length is measured. Taller people generally have a longer small intestine and measurements are generally longer after death and when the bowel is empty.
It is approximately in diameter in newborns after 35 weeks of gestational age, and in diameter in adults. On abdominal X-rays, the small intestine is considered to be abnormally dilated when the diameter exceeds 3 cm. On CT scans, a diameter of over 2.5 cm is considered abnormally dilated. The surface area of the human small intestinal mucosa, due to enlargement caused by folds, villi and microvilli, averages .
Parts
The small intestine is divided into three structural parts.
The duodenum is a short structure ranging from in length, and shaped like a "C". It surrounds the head of t
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The major duodenal papilla (papilla of Vater) is a rounded projection in the duodenum into which the common bile duct and pancreatic duct drain. The major duodenal papilla is, in most people, the primary mechanism for the secretion of bile and other enzymes that facilitate digestion.
Structure
The major duodenal papilla is situated in the second part of the duodenum, 7–10 cm from the pylorus, at the level of the second or third lumbar vertebrae. It is surrounded by the sphincter of Oddi, a circular muscle, and receives a mixture of pancreatic enzymes and bile from the Ampulla of Vater, which drains both the pancreatic duct and biliary system. The junction between the foregut and midgut occurs directly below the major duodenal papilla. The major duodenal papilla projects less than a centimetre into the lumen of the duodenum. It appears rounded and is often covered by a fold on the uppermost side of the papilla; that is, the side which receives contents from the stomach.
The major duodenal papilla is seen from the duodenum as lying within a mucosal fold. The minor duodenal papilla is situated 2 cm proximal.
Variation
The major duodenal papilla is occasionally found in the junction between the descending and horizontal parts of the duodenum, or in the horizontal part of the duodenum; a case study of 1000 people demonstrated this in 12 and 8% respectively. in the third part of the duodenum, the level of the vertebrae may be L2-3, and in about 10% of people, it may not receive bile. Additionally, in a small number of people, the primary papilla for draining the pancreas may in fact be the accessory pancreatic duct.
Function
Pancreatic enzymes and bile drain into the duodenum from both the pancreatic duct and biliary system. This facilitates the digestion of food; particularly proteins (pancreatic enzymes), and fat-soluble vitamins (bile).
Clinical significance
The minor papilla drains the duct of Santorini, superior in position to the major papilla. In pancreati
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
The duodenum is the first and the shortest part of what, and is where most chemical digestion takes place?
A. rectum
B. stomach
C. large intestine
D. small intestine
Answer:
|
|
sciq-9119
|
multiple_choice
|
Zoonotic pathogens are transferred from what to what?
|
[
"animals to humans",
"animals to animals",
"humans to humans",
"humans to animals"
] |
A
|
Relavent Documents:
Document 0:::
MicrobeLibrary is a permanent collection of over 1400 original peer-reviewed resources for teaching undergraduate microbiology. It is provided by the American Society for Microbiology, Washington DC, United States.
Contents include curriculum activities; images and animations; reviews of books, websites and other resources; and articles from Focus on Microbiology Education, Microbiology Education and Microbe. Around 40% of the materials are free to educators and students, the remainder require a subscription. the service is suspended with the message to:
"Please check back with us in 2017".
External links
MicrobeLibrary
Microbiology
Document 1:::
Several universities have designed interdisciplinary courses with a focus on human biology at the undergraduate level. There is a wide variation in emphasis ranging from business, social studies, public policy, healthcare and pharmaceutical research.
Americas
Human Biology major at Stanford University, Palo Alto (since 1970)
Stanford's Human Biology Program is an undergraduate major; it integrates the natural and social sciences in the study of human beings. It is interdisciplinary and policy-oriented and was founded in 1970 by a group of Stanford faculty (Professors Dornbusch, Ehrlich, Hamburg, Hastorf, Kennedy, Kretchmer, Lederberg, and Pittendrigh). It is a very popular major and alumni have gone to post-graduate education, medical school, law, business and government.
Human and Social Biology (Caribbean)
Human and Social Biology is a Level 4 & 5 subject in the secondary and post-secondary schools in the Caribbean and is optional for the Caribbean Secondary Education Certification (CSEC) which is equivalent to Ordinary Level (O-Level) under the British school system. The syllabus centers on structure and functioning (anatomy, physiology, biochemistry) of human body and the relevance to human health with Caribbean-specific experience. The syllabus is organized under five main sections: Living organisms and the environment, life processes, heredity and variation, disease and its impact on humans, the impact of human activities on the environment.
Human Biology Program at University of Toronto
The University of Toronto offers an undergraduate program in Human Biology that is jointly offered by the Faculty of Arts & Science and the Faculty of Medicine. The program offers several major and specialist options in: human biology, neuroscience, health & disease, global health, and fundamental genetics and its applications.
Asia
BSc (Honours) Human Biology at All India Institute of Medical Sciences, New Delhi (1980–2002)
BSc (honours) Human Biology at AIIMS (New
Document 2:::
Animal science is described as "studying the biology of animals that are under the control of humankind". It can also be described as the production and management of farm animals. Historically, the degree was called animal husbandry and the animals studied were livestock species, like cattle, sheep, pigs, poultry, and horses. Today, courses available look at a broader area, including companion animals, like dogs and cats, and many exotic species. Degrees in Animal Science are offered at a number of colleges and universities. Animal science degrees are often offered at land-grant universities, which will often have on-campus farms to give students hands-on experience with livestock animals.
Education
Professional education in animal science prepares students for careers in areas such as animal breeding, food and fiber production, nutrition, animal agribusiness, animal behavior, and welfare. Courses in a typical Animal Science program may include genetics, microbiology, animal behavior, nutrition, physiology, and reproduction. Courses in support areas, such as genetics, soils, agricultural economics and marketing, legal aspects, and the environment also are offered.
Bachelor degree
At many universities, a Bachelor of Science (BS) degree in Animal Science allows emphasis in certain areas. Typical areas are species-specific or career-specific. Species-specific areas of emphasis prepare students for a career in dairy management, beef management, swine management, sheep or small ruminant management, poultry production, or the horse industry. Other career-specific areas of study include pre-veterinary medicine studies, livestock business and marketing, animal welfare and behavior, animal nutrition science, animal reproduction science, or genetics. Youth programs are also an important part of animal science programs.
Pre-veterinary emphasis
Many schools that offer a degree option in Animal Science also offer a pre-veterinary emphasis such as Iowa State University, th
Document 3:::
This list of life sciences comprises the branches of science that involve the scientific study of life – such as microorganisms, plants, and animals including human beings. This science is one of the two major branches of natural science, the other being physical science, which is concerned with non-living matter. Biology is the overall natural science that studies life, with the other life sciences as its sub-disciplines.
Some life sciences focus on a specific type of organism. For example, zoology is the study of animals, while botany is the study of plants. Other life sciences focus on aspects common to all or many life forms, such as anatomy and genetics. Some focus on the micro-scale (e.g. molecular biology, biochemistry) other on larger scales (e.g. cytology, immunology, ethology, pharmacy, ecology). Another major branch of life sciences involves understanding the mindneuroscience. Life sciences discoveries are helpful in improving the quality and standard of life and have applications in health, agriculture, medicine, and the pharmaceutical and food science industries. For example, it has provided information on certain diseases which has overall aided in the understanding of human health.
Basic life science branches
Biology – scientific study of life
Anatomy – study of form and function, in plants, animals, and other organisms, or specifically in humans
Astrobiology – the study of the formation and presence of life in the universe
Bacteriology – study of bacteria
Biotechnology – study of combination of both the living organism and technology
Biochemistry – study of the chemical reactions required for life to exist and function, usually a focus on the cellular level
Bioinformatics – developing of methods or software tools for storing, retrieving, organizing and analyzing biological data to generate useful biological knowledge
Biolinguistics – the study of the biology and evolution of language.
Biological anthropology – the study of humans, non-hum
Document 4:::
Biosafety level 4 (BSL-4) organisms are dangerous or exotic agents which pose high risk of life-threatening disease, aerosol-transmitted lab infections, or related agents with unknown risk of transmission.
US federal biocontainment regulations
Biosafety level 4 laboratories are designed for diagnostic work and research on easily respiratory-acquired viruses which can often cause severe and/or fatal disease. What follows is a list of select agents that have specific biocontainment requirements according to US federal law. Organisms include those harmful to human health, or to animal health. The Plant Protection and Quarantine programs (PPQ) of the Animal and Plant Health Inspection Service (APHIS) are listed in 7 CFR Part 331. The Department of Health and Human Services (HHS) lists are located at 42 CFR Part 73.3 and 42 CFR Part 73.4. The USDA animal safety list is located at 9 CFR Subchapter B.
Not all select agents require BSL-4 handling, namely select bacteria and toxins, but most select agent viruses do (with the notable exception of SARS-CoV-1 which can be handled in BSL3). Many non-select agent viruses are often handled in BSL-4 according to facility SOPs or when dealing with new viruses closely related to viruses that require BSL-4. For instance, Andes orthohantavirus and MERS-CoV are both non-select agents that are often handled in BSL-4 because they cause severe and fatal disease in humans. Newly characterized viruses closely related to select agents and/or BSL-4 viruses (for example newly discovered henipaviruses or ebolaviruses) are typically handled in BSL-4 even if they aren't yet known to be readily transmissible or cause severe disease.
International BSL-4 regulations
Globally, there are no official agreements on what agents must be handled in BSL-4. However, select agents and toxins originating or ending in US BSL-4 labs must adhere to US select agent laws.
Select agents
HHS human threats: select agents and toxins
Crimean-Congo hemorrhagic fe
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Zoonotic pathogens are transferred from what to what?
A. animals to humans
B. animals to animals
C. humans to humans
D. humans to animals
Answer:
|
|
sciq-4189
|
multiple_choice
|
What are the two types of cells?
|
[
"bacteria and eukaryotes",
"mammal and plant",
"prokaryotes and eukaryotes",
"animal and bacteria"
] |
C
|
Relavent Documents:
Document 0:::
The cell is the basic structural and functional unit of all forms of life. Every cell consists of cytoplasm enclosed within a membrane, and contains many macromolecules such as proteins, DNA and RNA, as well as many small molecules of nutrients and metabolites. The term comes from the Latin word meaning 'small room'.
Cells can acquire specified function and carry out various tasks within the cell such as replication, DNA repair, protein synthesis, and motility. Cells are capable of specialization and mobility within the cell.
Most plant and animal cells are only visible under a light microscope, with dimensions between 1 and 100 micrometres. Electron microscopy gives a much higher resolution showing greatly detailed cell structure. Organisms can be classified as unicellular (consisting of a single cell such as bacteria) or multicellular (including plants and animals). Most unicellular organisms are classed as microorganisms.
The study of cells and how they work has led to many other studies in related areas of biology, including: discovery of DNA, cancer systems biology, aging and developmental biology.
Cell biology is the study of cells, which were discovered by Robert Hooke in 1665, who named them for their resemblance to cells inhabited by Christian monks in a monastery. Cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, and that all cells come from pre-existing cells. Cells emerged on Earth about 4 billion years ago.
Discovery
With continual improvements made to microscopes over time, magnification technology became advanced enough to discover cells. This discovery is largely attributed to Robert Hooke, and began the scientific study of cells, known as cell biology. When observing a piece of cork under the scope, he was able to see pores. This was shocking at the time as i
Document 1:::
Cellular components are the complex biomolecules and structures of which cells, and thus living organisms, are composed. Cells are the structural and functional units of life. The smallest organisms are single cells, while the largest organisms are assemblages of trillions of cells. DNA, double stranded macromolecule that carries the hereditary information of the cell and found in all living cells; each cell carries chromosome(s) having a distinctive DNA sequence.
Examples include macromolecules such as proteins and nucleic acids, biomolecular complexes such as a ribosome, and structures such as membranes, and organelles. While the majority of cellular components are located within the cell itself, some may exist in extracellular areas of an organism.
Cellular components may also be called biological matter or biological material. Most biological matter has the characteristics of soft matter, being governed by relatively small energies. All known life is made of biological matter. To be differentiated from other theoretical or fictional life forms, such life may be called carbon-based, cellular, organic, biological, or even simply living – as some definitions of life exclude hypothetical types of biochemistry.
See also
Cell (biology)
Cell biology
Biomolecule
Organelle
Tissue (biology)
External links
https://web.archive.org/web/20130918033010/http://bioserv.fiu.edu/~walterm/FallSpring/review1_fall05_chap_cell3.htm
Document 2:::
Cell physiology is the biological study of the activities that take place in a cell to keep it alive. The term physiology refers to normal functions in a living organism. Animal cells, plant cells and microorganism cells show similarities in their functions even though they vary in structure.
General characteristics
There are two types of cells: prokaryotes and eukaryotes.
Prokaryotes were the first of the two to develop and do not have a self-contained nucleus. Their mechanisms are simpler than later-evolved eukaryotes, which contain a nucleus that envelops the cell's DNA and some organelles.
Prokaryotes
Prokaryotes have DNA located in an area called the nucleoid, which is not separated from other parts of the cell by a membrane. There are two domains of prokaryotes: bacteria and archaea. Prokaryotes have fewer organelles than eukaryotes. Both have plasma membranes and ribosomes (structures that synthesize proteins and float free in cytoplasm). Two unique characteristics of prokaryotes are fimbriae (finger-like projections on the surface of a cell) and flagella (threadlike structures that aid movement).
Eukaryotes
Eukaryotes have a nucleus where DNA is contained. They are usually larger than prokaryotes and contain many more organelles. The nucleus, the feature of a eukaryote that distinguishes it from a prokaryote, contains a nuclear envelope, nucleolus and chromatin. In cytoplasm, endoplasmic reticulum (ER) synthesizes membranes and performs other metabolic activities. There are two types, rough ER (containing ribosomes) and smooth ER (lacking ribosomes). The Golgi apparatus consists of multiple membranous sacs, responsible for manufacturing and shipping out materials such as proteins. Lysosomes are structures that use enzymes to break down substances through phagocytosis, a process that comprises endocytosis and exocytosis. In the mitochondria, metabolic processes such as cellular respiration occur. The cytoskeleton is made of fibers that support the str
Document 3:::
A cell type is a classification used to identify cells that share morphological or phenotypical features. A multicellular organism may contain cells of a number of widely differing and specialized cell types, such as muscle cells and skin cells, that differ both in appearance and function yet have identical genomic sequences. Cells may have the same genotype, but belong to different cell types due to the differential regulation of the genes they contain. Classification of a specific cell type is often done through the use of microscopy (such as those from the cluster of differentiation family that are commonly used for this purpose in immunology). Recent developments in single cell RNA sequencing facilitated classification of cell types based on shared gene expression patterns. This has led to the discovery of many new cell types in e.g. mouse cortex, hippocampus, dorsal root ganglion and spinal cord.
Animals have evolved a greater diversity of cell types in a multicellular body (100–150 different cell types), compared
with 10–20 in plants, fungi, and protists. The exact number of cell types is, however, undefined, and the Cell Ontology, as of 2021, lists over 2,300 different cell types.
Multicellular organisms
All higher multicellular organisms contain cells specialised for different functions. Most distinct cell types arise from a single totipotent cell that differentiates into hundreds of different cell types during the course of development. Differentiation of cells is driven by different environmental cues (such as cell–cell interaction) and intrinsic differences (such as those caused by the uneven distribution of molecules during division). Multicellular organisms are composed of cells that fall into two fundamental types: germ cells and somatic cells. During development, somatic cells will become more specialized and form the three primary germ layers: ectoderm, mesoderm, and endoderm. After formation of the three germ layers, cells will continue to special
Document 4:::
This lecture, named in memory of Keith R. Porter, is presented to an eminent cell biologist each year at the ASCB Annual Meeting. The ASCB Program Committee and the ASCB President recommend the Porter Lecturer to the Porter Endowment each year.
Lecturers
Source: ASCB
See also
List of biology awards
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What are the two types of cells?
A. bacteria and eukaryotes
B. mammal and plant
C. prokaryotes and eukaryotes
D. animal and bacteria
Answer:
|
|
sciq-3801
|
multiple_choice
|
What is the major cause of outdoor air pollution?
|
[
"agricultural equipment",
"burning fossil fuels",
"electric lines",
"manufacturing industry"
] |
B
|
Relavent Documents:
Document 0:::
A pre-STEM program is a course of study at any two-year college that prepares a student to transfer to a four-year school to earn a bachelor's degree in a STEM field.
Overview
The concept of a pre-STEM program is being developed to address America's need for more college-trained professionals in science, technology, engineering, and mathematics (STEM). It is an innovation meant to fill a gap at community colleges that do not have 'major' degree paths that students identify with on their way to earning an Associates degree. Students must complete a considerable amount of STEM coursework before transferring from a two-year school to a four-year school and earn a baccalaureate degree in a STEM field. Schools with a pre-STEM program are able to identify those students and support them with STEM-specific academic and career advising, increasing the student's chances of going on to earn a STEM baccalaureate degree in a timely fashion.
With over 50% of America's college-bound students starting their college career at public or private two-year school, and with a very small proportion of students who start college at a two-year school matriculating to and earning STEM degrees from four-year schools, pre-STEM programs have great potential for broadening participation in baccalaureate STEM studies.
Example programs
The effectiveness of pre-STEM programs is being investigated by a consortium of schools in Missouri: Moberly Area Community College, St. Charles Community College, Metropolitan Community College, and Truman State University.
A larger group of schools met at the Belknap Springs Meetings in October 2009 to discuss the challenges and opportunities presented by STEM-focused partnerships between 2-year and 4-year schools. Each program represented a two-year school and a four-year school that were trying to increase the number of people who earn a baccalaureate degree in a STEM area through various means, some of which were pre-STEM programs. Other methods includes
Document 1:::
The STEM (Science, Technology, Engineering, and Mathematics) pipeline is a critical infrastructure for fostering the development of future scientists, engineers, and problem solvers. It's the educational and career pathway that guides individuals from early childhood through to advanced research and innovation in STEM-related fields.
Description
The "pipeline" metaphor is based on the idea that having sufficient graduates requires both having sufficient input of students at the beginning of their studies, and retaining these students through completion of their academic program. The STEM pipeline is a key component of workplace diversity and of workforce development that ensures sufficient qualified candidates are available to fill scientific and technical positions.
The STEM pipeline was promoted in the United States from the 1970s onwards, as “the push for STEM (science, technology, engineering, and mathematics) education appears to have grown from a concern for the low number of future professionals to fill STEM jobs and careers and economic and educational competitiveness.”
Today, this metaphor is commonly used to describe retention problems in STEM fields, called “leaks” in the pipeline. For example, the White House reported in 2012 that 80% of minority groups and women who enroll in a STEM field switch to a non-STEM field or drop out during their undergraduate education. These leaks often vary by field, gender, ethnic and racial identity, socioeconomic background, and other factors, drawing attention to structural inequities involved in STEM education and careers.
Current efforts
The STEM pipeline concept is a useful tool for programs aiming at increasing the total number of graduates, and is especially important in efforts to increase the number of underrepresented minorities and women in STEM fields. Using STEM methodology, educational policymakers can examine the quantity and retention of students at all stages of the K–12 educational process and beyo
Document 2:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 3:::
Female education in STEM refers to child and adult female representation in the educational fields of science, technology, engineering, and mathematics (STEM). In 2017, 33% of students in STEM fields were women.
The organization UNESCO has stated that this gender disparity is due to discrimination, biases, social norms and expectations that influence the quality of education women receive and the subjects they study. UNESCO also believes that having more women in STEM fields is desirable because it would help bring about sustainable development.
Current status of girls and women in STEM education
Overall trends in STEM education
Gender differences in STEM education participation are already visible in early childhood care and education in science- and math-related play, and become more pronounced at higher levels of education. Girls appear to lose interest in STEM subjects with age, particularly between early and late adolescence. This decreased interest affects participation in advanced studies at the secondary level and in higher education. Female students represent 35% of all students enrolled in STEM-related fields of study at this level globally. Differences are also observed by disciplines, with female enrollment lowest in engineering, manufacturing and construction, natural science, mathematics and statistics and ICT fields. Significant regional and country differences in female representation in STEM studies can be observed, though, suggesting the presence of contextual factors affecting girls’ and women's engagement in these fields. Women leave STEM disciplines in disproportionate numbers during their higher education studies, in their transition to the world of work and even in their career cycle.
Learning achievement in STEM education
Data on gender differences in learning achievement present a complex picture, depending on what is measured (subject, knowledge acquisition against knowledge application), the level of education/age of students, and
Document 4:::
The Science, Technology, Engineering and Mathematics Network or STEMNET is an educational charity in the United Kingdom that seeks to encourage participation at school and college in science and engineering-related subjects (science, technology, engineering, and mathematics) and (eventually) work.
History
It is based at Woolgate Exchange near Moorgate tube station in London and was established in 1996. The chief executive is Kirsten Bodley. The STEMNET offices are housed within the Engineering Council.
Function
Its chief aim is to interest children in science, technology, engineering and mathematics. Primary school children can start to have an interest in these subjects, leading secondary school pupils to choose science A levels, which will lead to a science career. It supports the After School Science and Engineering Clubs at schools. There are also nine regional Science Learning Centres.
STEM ambassadors
To promote STEM subjects and encourage young people to take up jobs in these areas, STEMNET have around 30,000 ambassadors across the UK. these come from a wide selection of the STEM industries and include TV personalities like Rob Bell.
Funding
STEMNET used to receive funding from the Department for Education and Skills. Since June 2007, it receives funding from the Department for Children, Schools and Families and Department for Innovation, Universities and Skills, since STEMNET sits on the chronological dividing point (age 16) of both of the new departments.
See also
The WISE Campaign
Engineering and Physical Sciences Research Council
National Centre for Excellence in Teaching Mathematics
Association for Science Education
Glossary of areas of mathematics
Glossary of astronomy
Glossary of biology
Glossary of chemistry
Glossary of engineering
Glossary of physics
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What is the major cause of outdoor air pollution?
A. agricultural equipment
B. burning fossil fuels
C. electric lines
D. manufacturing industry
Answer:
|
|
sciq-9906
|
multiple_choice
|
What type of cells are gametes?
|
[
"proteins",
"immune",
"cardiac",
"reproductive"
] |
D
|
Relavent Documents:
Document 0:::
A cell type is a classification used to identify cells that share morphological or phenotypical features. A multicellular organism may contain cells of a number of widely differing and specialized cell types, such as muscle cells and skin cells, that differ both in appearance and function yet have identical genomic sequences. Cells may have the same genotype, but belong to different cell types due to the differential regulation of the genes they contain. Classification of a specific cell type is often done through the use of microscopy (such as those from the cluster of differentiation family that are commonly used for this purpose in immunology). Recent developments in single cell RNA sequencing facilitated classification of cell types based on shared gene expression patterns. This has led to the discovery of many new cell types in e.g. mouse cortex, hippocampus, dorsal root ganglion and spinal cord.
Animals have evolved a greater diversity of cell types in a multicellular body (100–150 different cell types), compared
with 10–20 in plants, fungi, and protists. The exact number of cell types is, however, undefined, and the Cell Ontology, as of 2021, lists over 2,300 different cell types.
Multicellular organisms
All higher multicellular organisms contain cells specialised for different functions. Most distinct cell types arise from a single totipotent cell that differentiates into hundreds of different cell types during the course of development. Differentiation of cells is driven by different environmental cues (such as cell–cell interaction) and intrinsic differences (such as those caused by the uneven distribution of molecules during division). Multicellular organisms are composed of cells that fall into two fundamental types: germ cells and somatic cells. During development, somatic cells will become more specialized and form the three primary germ layers: ectoderm, mesoderm, and endoderm. After formation of the three germ layers, cells will continue to special
Document 1:::
Embryomics is the identification, characterization and study of the diverse cell types which arise during embryogenesis, especially as this relates to the location and developmental history of cells in the embryo. Cell type may be determined according to several criteria: location in the developing embryo, gene expression as indicated by protein and nucleic acid markers and surface antigens, and also position on the embryogenic tree.
Embryome
There are many cell markers useful in distinguishing, classifying, separating and purifying the numerous cell types present at any given time in a developing organism. These cell markers consist of select RNAs and proteins present inside, and surface antigens present on the surface of, the cells making up the embryo. For any given cell type, these RNA and protein markers reflect the genes characteristically active in that cell type. The catalog of all these cell types and their characteristic markers is known as the organism's embryome. The word is a portmanteau of embryo and genome. “Embryome” may also refer to the totality of the physical cell markers themselves.
Embryogenesis
As an embryo develops from a fertilized egg, the single egg cell splits into many cells, which grow in number and migrate to the appropriate locations inside the embryo at appropriate times during development. As the embryo's cells grow in number and migrate, they also differentiate into an increasing number of different cell types, ultimately turning into the stable, specialized cell types characteristic of the adult organism. Each of the cells in an embryo contains the same genome, characteristic of the species, but the level of activity of each of the many thousands of genes that make up the complete genome varies with, and determines, a particular cell's type (e.g. neuron, bone cell, skin cell, muscle cell, etc.).
During embryo development (embryogenesis), many cell types are present which are not present in the adult organism. These temporary c
Document 2:::
Adult stem cells are undifferentiated cells, found throughout the body after development, that multiply by cell division to replenish dying cells and regenerate damaged tissues. Also known as somatic stem cells (from Greek σωματικóς, meaning of the body), they can be found in juvenile, adult animals, and humans, unlike embryonic stem cells.
Scientific interest in adult stem cells is centered around two main characteristics. The first of which is their ability to divide or self-renew indefinitely, and the second their ability to generate all the cell types of the organ from which they originate, potentially regenerating the entire organ from a few cells. Unlike embryonic stem cells, the use of human adult stem cells in research and therapy is not considered to be controversial, as they are derived from adult tissue samples rather than human embryos designated for scientific research. The main functions of adult stem cells are to replace cells that are at risk of possibly dying as a result of disease or injury and to maintain a state of homeostasis within the cell. There are three main methods to determine if the adult stem cell is capable of becoming a specialized cell. The adult stem cell can be labeled in vivo and tracked, it can be isolated and then transplanted back into the organism, and it can be isolated in vivo and manipulated with growth hormones. They have mainly been studied in humans and model organisms such as mice and rats.
Structure
Defining properties
A stem cell possesses two properties:
Self-renewal is the ability to go through numerous cycles of cell division while still maintaining its undifferentiated state. Stem cells can replicate several times and can result in the formation of two stem cells, one stem cell more differentiated than the other, or two differentiated cells.
Multipotency or multidifferentiative potential is the ability to generate progeny of several distinct cell types, (for example glial cells and neurons) as opposed to u
Document 3:::
Cellular components are the complex biomolecules and structures of which cells, and thus living organisms, are composed. Cells are the structural and functional units of life. The smallest organisms are single cells, while the largest organisms are assemblages of trillions of cells. DNA, double stranded macromolecule that carries the hereditary information of the cell and found in all living cells; each cell carries chromosome(s) having a distinctive DNA sequence.
Examples include macromolecules such as proteins and nucleic acids, biomolecular complexes such as a ribosome, and structures such as membranes, and organelles. While the majority of cellular components are located within the cell itself, some may exist in extracellular areas of an organism.
Cellular components may also be called biological matter or biological material. Most biological matter has the characteristics of soft matter, being governed by relatively small energies. All known life is made of biological matter. To be differentiated from other theoretical or fictional life forms, such life may be called carbon-based, cellular, organic, biological, or even simply living – as some definitions of life exclude hypothetical types of biochemistry.
See also
Cell (biology)
Cell biology
Biomolecule
Organelle
Tissue (biology)
External links
https://web.archive.org/web/20130918033010/http://bioserv.fiu.edu/~walterm/FallSpring/review1_fall05_chap_cell3.htm
Document 4:::
Cell physiology is the biological study of the activities that take place in a cell to keep it alive. The term physiology refers to normal functions in a living organism. Animal cells, plant cells and microorganism cells show similarities in their functions even though they vary in structure.
General characteristics
There are two types of cells: prokaryotes and eukaryotes.
Prokaryotes were the first of the two to develop and do not have a self-contained nucleus. Their mechanisms are simpler than later-evolved eukaryotes, which contain a nucleus that envelops the cell's DNA and some organelles.
Prokaryotes
Prokaryotes have DNA located in an area called the nucleoid, which is not separated from other parts of the cell by a membrane. There are two domains of prokaryotes: bacteria and archaea. Prokaryotes have fewer organelles than eukaryotes. Both have plasma membranes and ribosomes (structures that synthesize proteins and float free in cytoplasm). Two unique characteristics of prokaryotes are fimbriae (finger-like projections on the surface of a cell) and flagella (threadlike structures that aid movement).
Eukaryotes
Eukaryotes have a nucleus where DNA is contained. They are usually larger than prokaryotes and contain many more organelles. The nucleus, the feature of a eukaryote that distinguishes it from a prokaryote, contains a nuclear envelope, nucleolus and chromatin. In cytoplasm, endoplasmic reticulum (ER) synthesizes membranes and performs other metabolic activities. There are two types, rough ER (containing ribosomes) and smooth ER (lacking ribosomes). The Golgi apparatus consists of multiple membranous sacs, responsible for manufacturing and shipping out materials such as proteins. Lysosomes are structures that use enzymes to break down substances through phagocytosis, a process that comprises endocytosis and exocytosis. In the mitochondria, metabolic processes such as cellular respiration occur. The cytoskeleton is made of fibers that support the str
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What type of cells are gametes?
A. proteins
B. immune
C. cardiac
D. reproductive
Answer:
|
|
sciq-6388
|
multiple_choice
|
What is the movement of molecules from an area of high concentration of the molecules to an area with a lower concentration?
|
[
"diffusion",
"condensation",
"absorption",
"secretion"
] |
A
|
Relavent Documents:
Document 0:::
Transcellular transport involves the transportation of solutes by a cell through a cell. Transcellular transport can occur in three different ways active transport, passive transport, and transcytosis.
Active Transport
Main article: Active transport
Active transport is the process of moving molecules from an area of low concentrations to an area of high concentration. There are two types of active transport, primary active transport and secondary active transport. Primary active transport uses adenosine triphosphate (ATP) to move specific molecules and solutes against its concentration gradient. Examples of molecules that follow this process are potassium K+, sodium Na+, and calcium Ca2+. A place in the human body where this occurs is in the intestines with the uptake of glucose. Secondary active transport is when one solute moves down the electrochemical gradient to produce enough energy to force the transport of another solute from low concentration to high concentration. An example of where this occurs is in the movement of glucose within the proximal convoluted tubule (PCT).
Passive Transport
Main article: Passive transport
Passive transport is the process of moving molecules from an area of high concentration to an area of low concentration without expelling any energy. There are two types of passive transport, passive diffusion and facilitated diffusion. Passive diffusion is the unassisted movement of molecules from high concentration to low concentration across a permeable membrane. One example of passive diffusion is the gas exchange that occurs between the oxygen in the blood and the carbon dioxide present in the lungs. Facilitated diffusion is the movement of polar molecules down the concentration gradient with the assistance of membrane proteins. Since the molecules associated with facilitated diffusion are polar, they are repelled by the hydrophobic sections of permeable membrane, therefore they need to be assisted by the membrane proteins. Both t
Document 1:::
Passive transport is a type of membrane transport that does not require energy to move substances across cell membranes. Instead of using cellular energy, like active transport, passive transport relies on the second law of thermodynamics to drive the movement of substances across cell membranes. Fundamentally, substances follow Fick's first law, and move from an area of high concentration to an area of low concentration because this movement increases the entropy of the overall system. The rate of passive transport depends on the permeability of the cell membrane, which, in turn, depends on the organization and characteristics of the membrane lipids and proteins. The four main kinds of passive transport are simple diffusion, facilitated diffusion, filtration, and/or osmosis.
Passive transport follows Fick's first law.
Diffusion
Diffusion is the net movement of material from an area of high concentration to an area with lower concentration. The difference of concentration between the two areas is often termed as the concentration gradient, and diffusion will continue until this gradient has been eliminated. Since diffusion moves materials from an area of higher concentration to an area of lower concentration, it is described as moving solutes "down the concentration gradient" (compared with active transport, which often moves material from area of low concentration to area of higher concentration, and therefore referred to as moving the material "against the concentration gradient").
However, in many cases (e.g. passive drug transport) the driving force of passive transport can not be simplified to the concentration gradient. If there are different solutions at the two sides of the membrane with different equilibrium solubility of the drug, the difference in the degree of saturation is the driving force of passive membrane transport. It is also true for supersaturated solutions which are more and more important owing to the spreading of the application of amorph
Document 2:::
The Stefan flow, occasionally called Stefan's flow, is a transport phenomenon concerning the movement of a chemical species by a flowing fluid (typically in the gas phase) that is induced to flow by the production or removal of the species at an interface. Any process that adds the species of interest to or removes it from the flowing fluid may cause the Stefan flow, but the most common processes include evaporation, condensation, chemical reaction, sublimation, ablation, adsorption, absorption, and desorption. It was named after the Slovenian physicist, mathematician, and poet Josef Stefan for his early work on calculating evaporation rates.
The Stefan flow is distinct from diffusion as described by Fick's law, but diffusion almost always also occurs in multi-species systems that are experiencing the Stefan flow. In systems undergoing one of the species addition or removal processes mentioned previously, the addition or removal generates a mean flow in the flowing fluid as the fluid next to the interface is displaced by the production or removal of additional fluid by the processes occurring at the interface. The transport of the species by this mean flow is the Stefan flow. When concentration gradients of the species are also present, diffusion transports the species relative to the mean flow. The total transport rate of the species is then given by a summation of the Stefan flow and diffusive contributions.
An example of the Stefan flow occurs when a droplet of liquid evaporates in air. In this case, the vapor/air mixture surrounding the droplet is the flowing fluid, and liquid/vapor boundary of the droplet is the interface. As heat is absorbed by the droplet from the environment, some of the liquid evaporates into vapor at the surface of the droplet, and flows away from the droplet as it is displaced by additional vapor evaporating from the droplet. This process causes the flowing medium to move away from the droplet at some mean speed that is dependent on
Document 3:::
Rotational diffusion is the rotational movement which acts upon any object such as particles, molecules, atoms when present in a fluid, by random changes in their orientations.
Whilst the directions and intensities of these changes are statistically random, they do not arise randomly and are instead the result of interactions between particles. One example occurs in colloids, where relatively large insoluble particles are suspended in a greater amount of fluid. The changes in orientation occur from collisions between the particle and the many molecules forming the fluid surrounding the particle, which each transfer kinetic energy to the particle, and as such can be considered random due to the varied speeds and amounts of fluid molecules incident on each individual particle at any given time.
The analogue to translational diffusion which determines the particle's position in space, rotational diffusion randomises the orientation of any particle it acts on.
Anything in a solution will experience rotational diffusion, from the microscopic scale where individual atoms may have an effect on each other, to the macroscopic scale.
Applications
Rotational diffusion has multiple applications in chemistry and physics, and is heavily involved in many biology based fields. For example, protein-protein interaction is a vital step in the communication of biological signals. In order to communicate, the proteins must both come into contact with each other and be facing the appropriate way to interact with each other's binding site, which relies on the proteins ability to rotate.
As an example concerning physics, rotational Brownian motion in astronomy can be used to explain the orientations of the orbital planes of binary stars, as well as the seemingly random spin axes of supermassive black holes.
The random re-orientation of molecules (or larger systems) is an important process for many biophysical probes. Due to the equipartition theorem, larger molecules re-orient more s
Document 4:::
Transport by molecular motor proteins (Kinesin, Dynein and unconventional Myosin) is essential for cell functioning and survival. Studies of multiple motors are inspired by the fact that multiple motors are involved in many biological processes such as intra-cellular transport and mitosis. This increasing interest in modeling multiple motor transport is particularly due to improved understanding of single motor function. Several models have been proposed in recent year to understand the transport by multiple motors.
Models developed can be broadly divided into two categories (1) mean-field/steady state model and (2) stochastic model. The mean-field model is useful for describing transport by a large group of motors. In mean-field description, fluctuation in the forces that individual motors feel while pulling the cargo is ignored. In stochastic model, fluctuation in the forces that motors feel are not ignored. Steady-state/mean-field model is useful for modeling transport by a large group of motors whereas stochastic model is useful for modeling transport by few motors.
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What is the movement of molecules from an area of high concentration of the molecules to an area with a lower concentration?
A. diffusion
B. condensation
C. absorption
D. secretion
Answer:
|
|
sciq-4249
|
multiple_choice
|
Competition within a species is called what?
|
[
"reproducible competition",
"species competion",
"internal competition",
"intraspecific competition"
] |
D
|
Relavent Documents:
Document 0:::
Interspecific competition, in ecology, is a form of competition in which individuals of different species compete for the same resources in an ecosystem (e.g. food or living space). This can be contrasted with mutualism, a type of symbiosis. Competition between members of the same species is called intraspecific competition.
If a tree species in a dense forest grows taller than surrounding tree species, it is able to absorb more of the incoming sunlight. However, less sunlight is then available for the trees that are shaded by the taller tree, thus interspecific competition. Leopards and lions can also be in interspecific competition, since both species feed on the same prey, and can be negatively impacted by the presence of the other because they will have less food.
Competition is only one of many interacting biotic and abiotic factors that affect community structure. Moreover, competition is not always a straightforward, direct, interaction. Interspecific competition may occur when individuals of two separate species share a limiting resource in the same area. If the resource cannot support both populations, then lowered fecundity, growth, or survival may result in at least one species. Interspecific competition has the potential to alter populations, communities and the evolution of interacting species. On an individual organism level, competition can occur as interference or exploitative competition.
Types
All of the types described here can also apply to intraspecific competition, that is, competition among individuals within a species. Also, any specific example of interspecific competition can be described in terms of both a mechanism (e.g., resource or interference) and an outcome (symmetric or asymmetric).
Based on mechanism
Exploitative competition, also referred to as resource competition, is a form of competition in which one species consumes and either reduces or more efficiently uses a shared limiting resource and therefore depletes the availab
Document 1:::
Competition is an interaction between organisms or species in which both require a resource that is in limited supply (such as food, water, or territory). Competition lowers the fitness of both organisms involved since the presence of one of the organisms always reduces the amount of the resource available to the other.
In the study of community ecology, competition within and between members of a species is an important biological interaction. Competition is one of many interacting biotic and abiotic factors that affect community structure, species diversity, and population dynamics (shifts in a population over time).
There are three major mechanisms of competition: interference, exploitation, and apparent competition (in order from most direct to least direct). Interference and exploitation competition can be classed as "real" forms of competition, while apparent competition is not, as organisms do not share a resource, but instead share a predator. Competition among members of the same species is known as intraspecific competition, while competition between individuals of different species is known as interspecific competition.
According to the competitive exclusion principle, species less suited to compete for resources must either adapt or die out, although competitive exclusion is rarely found in natural ecosystems. According to evolutionary theory, competition within and between species for resources is important in natural selection. More recently, however, researchers have suggested that evolutionary biodiversity for vertebrates has been driven not by competition between organisms, but by these animals adapting to colonize empty livable space; this is termed the 'Room to Roam' hypothesis.
Interference competition
During interference competition, also called contest competition, organisms interact directly by fighting for scarce resources. For example, large aphids defend feeding sites on cottonwood leaves by ejecting smaller aphids from better sites.
Document 2:::
In ecology, contest competition refers to a situation where available resources, such as food and mates, are utilized only by one or a few individuals, thus preventing development or reproduction of other individuals. It refers to a hypothetical situation in which several individuals stage a contest for which one eventually emerges victorious. Contest competition is the opposite of scramble competition, a situation in which available resources are shared equally among individuals.
As contest competition allows the monopolization of resources, offspring will typically always be produced and survive until adulthood independent of the population size, resulting in stable population dynamics. This is in stark contrast to scramble competition which can result in periodic or chaotic population dynamics. The Beverton–Holt model is often used to represent population dynamics arising from contest competition. This model, and a few other well-known population models, can be explicitly derived from individual-level processes assuming contest competition and a random distribution of individuals among resources.
Contest competition has been observed in a variety of species. In white-faced monkeys, Cebus capucinus, regardless of aggression, avoidance, or sex, higher ranking monkeys had higher energy intake within their group. For female Microcebus murinus groups, if the resource (fruit) could be monopolized, they would compete within their group for it. In a controlled lab experiment with three parasitic wasp species (Dinarmus basalis, Anisopteromalus calandrae, and Heterospilus prosopidis) they found that between the first larvae in the host and the second, the larvae that would win depended on the time between them. There was also a Nicholson–Bailey model made to partially explain the relationship between Heterospilus prosopidis and its host Callosobruchus maculatus.
Fitness gains for the winner of the contest is not always known. For example, in mountain gorillas, Gorilla b
Document 3:::
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions from sub-disciplines and related fields, see Glossary of cell biology, Glossary of genetics, Glossary of evolutionary biology, Glossary of ecology, Glossary of environmental science and Glossary of scientific naming, or any of the organism-specific glossaries in :Category:Glossaries of biology.
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Related to this search
Index of biology articles
Outline of biology
Glossaries of sub-disciplines and related fields:
Glossary of botany
Glossary of ecology
Glossary of entomology
Glossary of environmental science
Glossary of genetics
Glossary of ichthyology
Glossary of ornithology
Glossary of scientific naming
Glossary of speciation
Glossary of virology
Document 4:::
Any action or influence that species have on each other is considered a biological interaction. These interactions between species can be considered in several ways. One such way is to depict interactions in the form of a network, which identifies the members and the patterns that connect them. Species interactions are considered primarily in terms of trophic interactions, which depict which species feed on others.
Currently, ecological networks that integrate non-trophic interactions are being built. The type of interactions they can contain can be classified into six categories: mutualism, commensalism, neutralism, amensalism, antagonism, and competition.
Observing and estimating the fitness costs and benefits of species interactions can be very problematic. The way interactions are interpreted can profoundly affect the ensuing conclusions.
Interaction characteristics
Characterization of interactions can be made according to various measures, or any combination of them.
Prevalence
Prevalence identifies the proportion of the population affected by a given interaction, and thus quantifies whether it is relatively rare or common. Generally, only common interactions are considered.
Negative/ Positive
Whether the interaction is beneficial or harmful to the species involved determines the sign of the interaction, and what type of interaction it is classified as. To establish whether they are harmful or beneficial, careful observational and/or experimental studies can be conducted, in an attempt to establish the cost/benefit balance experienced by the members.
Strength
The sign of an interaction does not capture the impact on fitness of that interaction. One example of this is of antagonism, in which predators may have a much stronger impact on their prey species (death), than parasites (reduction in fitness). Similarly, positive interactions can produce anything from a negligible change in fitness to a life or death impact.
Relationship in space and time
The rel
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Competition within a species is called what?
A. reproducible competition
B. species competion
C. internal competition
D. intraspecific competition
Answer:
|
|
sciq-10067
|
multiple_choice
|
When does an oocyte complete meiosis?
|
[
"metaphase",
"anaphase",
"after sperm penetration",
"prophase"
] |
C
|
Relavent Documents:
Document 0:::
Oogenesis, ovogenesis, or oögenesis is the differentiation of the ovum (egg cell) into a cell competent to further develop when fertilized. It is developed from the primary oocyte by maturation. Oogenesis is initiated in the embryonic stage.
Oogenesis in non-human mammals
In mammals, the first part of oogenesis starts in the germinal epithelium, which gives rise to the development of ovarian follicles, the functional unit of the ovary.
Oogenesis consists of several sub-processes: oocytogenesis, ootidogenesis, and finally maturation to form an ovum (oogenesis proper). Folliculogenesis is a separate sub-process that accompanies and supports all three oogenetic sub-processes.
Oogonium —(Oocytogenesis)—> Primary Oocyte —(Meiosis I)—> First Polar body (Discarded afterward) + Secondary oocyte —(Meiosis II)—> Second Polar Body (Discarded afterward) + Ovum
Oocyte meiosis, important to all animal life cycles yet unlike all other instances of animal cell division, occurs completely without the aid of spindle-coordinating centrosomes.
The creation of oogonia
The creation of oogonia traditionally doesn't belong to oogenesis proper, but, instead, to the common process of gametogenesis, which, in the female human, begins with the processes of folliculogenesis, oocytogenesis, and ootidogenesis. Oogonia enter meiosis during embryonic development, becoming oocytes. Meiosis begins with DNA replication and meiotic crossing over. It then stops in early prophase.
Maintenance of meiotic arrest
Mammalian oocytes are maintained in meiotic prophase arrest for a very long time—months in mice, years in humans. Initially the arrest is due to lack of sufficient cell cycle proteins to allow meiotic progression. However, as the oocyte grows, these proteins are synthesized, and meiotic arrest becomes dependent on cyclic AMP. The cyclic AMP is generated by the oocyte by adenylyl cyclase in the oocyte membrane. The adenylyl cyclase is kept active by a constitutively active G-protein-coupled
Document 1:::
Microgametogenesis is the process in plant reproduction where a microgametophyte develops in a pollen grain to the three-celled stage of its development. In flowering plants it occurs with a microspore mother cell inside the anther of the plant.
When the microgametophyte is first formed inside the pollen grain four sets of fertile cells called sporogenous cells are apparent. These cells are surrounded by a wall of sterile cells called the tapetum, which supplies food to the cell and eventually becomes the cell wall for the pollen grain. These sets of sporogenous cells eventually develop into diploid microspore mother cells. These microspore mother cells, also called microsporocytes, then undergo meiosis and become four microspore haploid cells. These new microspore cells then undergo mitosis and form a tube cell and a generative cell. The generative cell then undergoes mitosis one more time to form two male gametes, also called sperm.
See also
Gametogenesis
Document 2:::
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. While processes such as insemination or pollination which happen before the fusion of gametes are also sometimes informally referred to as fertilisation, these are technically separate processes. The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation.
History
In Antiquity, Aristotle conceived the formation of new individuals through fusion of male and female fluids, with form and function emerging gradually, in a mode called by him as epigenetic.
In 1784, Spallanzani established the need of interaction between the female's ovum and male's sperm to form a zygote in frogs. In 1827, von Baer observed a therian mammalian egg for the first time. Oscar Hertwig (1876), in Germany, described the fusion of nuclei of spermatozoa and of ova from sea urchin.
Evolution
The evolution of fertilisation is related to the origin of meiosis, as both are part of sexual reproduction, originated in eukaryotes. One theory states that meiosis originated from mitosis.
Fertilisation in plants
The gametes that participate in fertilisation of plants are the sperm (male) and the egg (female) cell. Various families of plants have differing methods by which the gametes produced by the male and female gametophytes come together and are fertilised. In Bryophyte land plants, fertilisation of the sperm and egg takes place within the archegonium. In seed plants, the male gametophyte is called a pollen grain. After pollination, the pollen grain germinates, and a pollen tube grows and penetrates the ovule through a tiny pore called a mic
Document 3:::
Interkinesis or interphase II is a period of rest that cells of some species enter during meiosis between meiosis I and meiosis II. No DNA replication occurs during interkinesis; however, replication does occur during the interphase I stage of meiosis (See meiosis I). During interkinesis, the spindles of the first meiotic division disassembles and the microtubules reassemble into two new spindles for the second meiotic division. Interkinesis follows telophase I; however, many plants skip telophase I and interkinesis, going immediately into prophase II. Each chromosome still consists of two chromatids. In this stage other organelle number may also increase.
Document 4:::
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete (haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote that develops into an organism composed of cells with two sets of chromosomes (diploid). This is typical in animals, though the number of chromosome sets and how that number changes in sexual reproduction varies, especially among plants, fungi, and other eukaryotes.
Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. Sexual reproduction also occurs in some unicellular eukaryotes. Sexual reproduction does not occur in prokaryotes, unicellular organisms without cell nuclei, such as bacteria and archaea. However, some processes in bacteria, including bacterial conjugation, transformation and transduction, may be considered analogous to sexual reproduction in that they incorporate new genetic information. Some proteins and other features that are key for sexual reproduction may have arisen in bacteria, but sexual reproduction is believed to have developed in an ancient eukaryotic ancestor.
In eukaryotes, diploid precursor cells divide to produce haploid cells in a process called meiosis. In meiosis, DNA is replicated to produce a total of four copies of each chromosome. This is followed by two cell divisions to generate haploid gametes. After the DNA is replicated in meiosis, the homologous chromosomes pair up so that their DNA sequences are aligned with each other. During this period before cell divisions, genetic information is exchanged between homologous chromosomes in genetic recombination. Homologous chromosomes contain highly similar but not identical information, and by exchanging similar but not identical regions, genetic recombination increases genetic diversity among future generations.
During sexual reproduction, two haploid gametes combine into one diploid ce
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
When does an oocyte complete meiosis?
A. metaphase
B. anaphase
C. after sperm penetration
D. prophase
Answer:
|
|
sciq-3501
|
multiple_choice
|
A solute generally does what to the freezing point of a solvent?
|
[
"raises it",
"regulates it",
"increases it",
"lowers it"
] |
D
|
Relavent Documents:
Document 0:::
Freezing-point depression is a drop in the maximum temperature at which a substance freezes, caused when a smaller amount of another, non-volatile substance is added. Examples include adding salt into water (used in ice cream makers and for de-icing roads), alcohol in water, ethylene or propylene glycol in water (used in antifreeze in cars), adding copper to molten silver (used to make solder that flows at a lower temperature than the silver pieces being joined), or the mixing of two solids such as impurities into a finely powdered drug.
In all cases, the substance added/present in smaller amounts is considered the solute, while the original substance present in larger quantity is thought of as the solvent. The resulting liquid solution or solid-solid mixture has a lower freezing point than the pure solvent or solid because the chemical potential of the solvent in the mixture is lower than that of the pure solvent, the difference between the two being proportional to the natural logarithm of the mole fraction. In a similar manner, the chemical potential of the vapor above the solution is lower than that above a pure solvent, which results in boiling-point elevation. Freezing-point depression is what causes sea water (a mixture of salt and other compounds in water) to remain liquid at temperatures below , the freezing point of pure water.
Explanation
Using vapour pressure
The freezing point is the temperature at which the liquid solvent and solid solvent are at equilibrium, so that their vapor pressures are equal. When a non-volatile solute is added to a volatile liquid solvent, the solution vapour pressure will be lower than that of the pure solvent. As a result, the solid will reach equilibrium with the solution at a lower temperature than with the pure solvent. This explanation in terms of vapor pressure is equivalent to the argument based on chemical potential, since the chemical potential of a vapor is logarithmically related to pressure. All of the colligati
Document 1:::
In thermodynamics, the cryoscopic constant, , relates molality to freezing point depression (which is a colligative property). It is the ratio of the latter to the former:
is the van ‘t Hoff factor, the number of particles the solute splits into or forms when dissolved.
is the molality of the solution.
Through cryoscopy, a known constant can be used to calculate an unknown molar mass. The term "cryoscopy" comes from Greek and means "freezing measurement." Freezing point depression is a colligative property, so depends only on the number of solute particles dissolved, not the nature of those particles. Cryoscopy is related to ebullioscopy, which determines the same value from the ebullioscopic constant (of boiling point elevation).
The value of , which depends on the nature of the solvent can be found out by the following equation:
is the ideal gas constant
is the molar mass of the solvent in kg mol−1
is the freezing point of the pure solvent in kelvins
represents the molar enthalpy of fusion of the solvent in J mol−1.
The for water is 1.853 K kg mol−1.
See also
List of boiling and freezing information of solvents
Document 2:::
Fractional freezing is a process used in process engineering and chemistry to separate substances with different melting points. It can be done by partial melting of a solid, for example in zone refining of silicon or metals, or by partial crystallization of a liquid, as in freeze distillation, also called normal freezing or progressive freezing. The initial sample is thus fractionated (separated into fractions).
Partial crystallization can also be achieved by adding a dilute solvent to the mixture, and cooling and concentrating the mixture by evaporating the solvent, a process called solution crystallization. Fractional freezing is generally used to produce ultra-pure solids, or to concentrate heat-sensitive liquids.
Freeze distillation
Freeze distillation is a misnomer, because it is not distillation but rather a process of enriching a solution by partially freezing it and removing frozen material that is poorer in the dissolved material than is the liquid portion left behind. Such enrichment parallels enrichment by true distillation, where the evaporated and re-condensed portion is richer than the liquid portion left behind.
Ethanol and liquid water are completely miscible, but ethanol is practically insoluble in water ice. That means almost pure water ice can be precipitated from a lean ethanol-water mixture by cooling it sufficiently. The precipitation of water ice from the mixture enriches ethanol in the remaining liquid phase. The two phases can then be separated by filtration or decanting. The temperature at which water ice starts to precipitate depends on the ethanol concentration. Consequently, at a given temperature and ethanol concentration, the freezing process will reach an equilibrium at a specific ratio of water ice and enriched ethanol solution with a specific ethanol concentration. The temperatures and mixing ratios of these phase equilibria can be read from the phase diagram of ethanol and water. The maximum enrichment of ethanol in the liquid
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Boiling-point elevation describes the phenomenon that the boiling point of a liquid (a solvent) will be higher when another compound is added, meaning that a solution has a higher boiling point than a pure solvent. This happens whenever a non-volatile solute, such as a salt, is added to a pure solvent, such as water. The boiling point can be measured accurately using an ebullioscope.
Explanation
The boiling point elevation is a colligative property, which means that it is dependent on the presence of dissolved particles and their number, but not their identity. It is an effect of the dilution of the solvent in the presence of a solute. It is a phenomenon that happens for all solutes in all solutions, even in ideal solutions, and does not depend on any specific solute–solvent interactions. The boiling point elevation happens both when the solute is an electrolyte, such as various salts, and a nonelectrolyte. In thermodynamic terms, the origin of the boiling point elevation is entropic and can be explained in terms of the vapor pressure or chemical potential of the solvent. In both cases, the explanation depends on the fact that many solutes are only present in the liquid phase and do not enter into the gas phase (except at extremely high temperatures).
Put in vapor pressure terms, a liquid boils at the temperature when its vapor pressure equals the surrounding pressure. For the solvent, the presence of the solute decreases its vapor pressure by dilution. A nonvolatile solute has a vapor pressure of zero, so the vapor pressure of the solution is less than the vapor pressure of the solvent. Thus, a higher temperature is needed for the vapor pressure to reach the surrounding pressure, and the boiling point is elevated.
Put in chemical potential terms, at the boiling point, the liquid phase and the gas (or vapor) phase have the same chemical potential (or vapor pressure) meaning that they are energetically equivalent. The chemical potential is dependent on the temper
Document 4:::
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution.
The extent of the solubility of a substance in a specific solvent is generally measured as the concentration of the solute in a saturated solution, one in which no more solute can be dissolved. At this point, the two substances are said to be at the solubility equilibrium. For some solutes and solvents, there may be no such limit, in which case the two substances are said to be "miscible in all proportions" (or just "miscible").
The solute can be a solid, a liquid, or a gas, while the solvent is usually solid or liquid. Both may be pure substances, or may themselves be solutions. Gases are always miscible in all proportions, except in very extreme situations, and a solid or liquid can be "dissolved" in a gas only by passing into the gaseous state first.
The solubility mainly depends on the composition of solute and solvent (including their pH and the presence of other dissolved substances) as well as on temperature and pressure. The dependency can often be explained in terms of interactions between the particles (atoms, molecules, or ions) of the two substances, and of thermodynamic concepts such as enthalpy and entropy.
Under certain conditions, the concentration of the solute can exceed its usual solubility limit. The result is a supersaturated solution, which is metastable and will rapidly exclude the excess solute if a suitable nucleation site appears.
The concept of solubility does not apply when there is an irreversible chemical reaction between the two substances, such as the reaction of calcium hydroxide with hydrochloric acid; even though one might say, informally, that one "dissolved" the other. The solubility is also not the same as the rate of solution, which is how fast a solid solute dissolves in a liquid solvent. This property de
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
A solute generally does what to the freezing point of a solvent?
A. raises it
B. regulates it
C. increases it
D. lowers it
Answer:
|
|
sciq-9591
|
multiple_choice
|
The sun’s energy is converted to chemical energy by a what?
|
[
"plant",
"mammal",
"amphibian",
"bacterium"
] |
A
|
Relavent Documents:
Document 0:::
The Bionic Leaf is a biomimetic system that gathers solar energy via photovoltaic cells that can be stored or used in a number of different functions. Bionic leaves can be composed of both synthetic (metals, ceramics, polymers, etc.) and organic materials (bacteria), or solely made of synthetic materials. The Bionic Leaf has the potential to be implemented in communities, such as urbanized areas to provide clean air as well as providing needed clean energy.
History
In 2009 at MIT, Daniel Nocera's lab first developed the "artificial leaf", a device made from silicon and an anode electrocatalyst for the oxidation of water, capable of splitting water into hydrogen and oxygen gases. In 2012, Nocera came to Harvard and The Silver Lab of Harvard Medical School joined Nocera’s team. Together the teams expanded the existing technology to create the Bionic Leaf. It merged the concept of the artificial leaf with genetically engineered bacteria that feed on the hydrogen and convert CO2 in the air into alcohol fuels or chemicals.
The first version of the teams Bionic Leaf was created in 2015 but the catalyst used was harmful to the bacteria. In 2016, a new catalyst was designed to solve this issue, named the "Bionic Leaf 2.0". Other versions of artificial leaves have been developed by the California Institute of Technology and the Joint Center for Artificial Photosynthesis, the University of Waterloo, and the University of Cambridge.
Mechanics
Photosynthesis
In natural photosynthesis, photosynthetic organisms produce energy-rich organic molecules from water and carbon dioxide by using solar radiation. Therefore, the process of photosynthesis removes carbon dioxide, a greenhouse gas, from the air. Artificial photosynthesis, as performed by the Bionic Leaf, is approximately 10 times more efficient than natural photosynthesis. Using a catalyst, the Bionic Leaf can remove excess carbon dioxide in the air and convert that to useful alcohol fuels, like isopropanol and isobutan
Document 1:::
In chemistry and particularly biochemistry, an energy-rich species (usually energy-rich molecule) or high-energy species (usually high-energy molecule) is a chemical species which reacts, potentially with other species found in the environment, to release chemical energy.
In particular, the term is often used for:
adenosine triphosphate (ATP) and similar molecules called high-energy phosphates, which release inorganic phosphate into the environment in an exothermic reaction with water:
ATP + → ADP + Pi ΔG°' = −30.5 kJ/mol (−7.3 kcal/mol)
fuels such as hydrocarbons, carbohydrates, lipids, proteins, and other organic molecules which react with oxygen in the environment to ultimately form carbon dioxide, water, and sometimes nitrogen, sulfates, and phosphates
molecular hydrogen
monatomic oxygen, ozone, hydrogen peroxide, singlet oxygen and other metastable or unstable species which spontaneously react without further reactants
in particular, the vast majority of free radicals
explosives such as nitroglycerin and other substances which react exothermically without requiring a second reactant
metals or metal ions which can be oxidized to release energy
This is contrasted to species that are either part of the environment (this sometimes includes diatomic triplet oxygen) or do not react with the environment (such as many metal oxides or calcium carbonate); those species are not considered energy-rich or high-energy species.
Alternative definitions
The term is often used without a definition. Some authors define the term "high-energy" to be equivalent to "chemically unstable", while others reserve the term for high-energy phosphates, such as the Great Soviet Encyclopedia which defines the term "high-energy compounds" to refer exclusively to those.
The IUPAC glossary of terms used in ecotoxicology defines a primary producer as an "organism capable of using the energy derived from light or a chemical substance in order to manufacture energy-rich organic compou
Document 2:::
The molecules that an organism uses as its carbon source for generating biomass are referred to as "carbon sources" in biology. It is possible for organic or inorganic sources of carbon. Heterotrophs must use organic molecules as both are a source of carbon and energy, in contrast to autotrophs, which can use inorganic materials as both a source of carbon and an abiotic source of energy, such as, for instance, inorganic chemical energy or light (photoautotrophs) (chemolithotrophs).
The carbon cycle, which begins with a carbon source that is inorganic, such as carbon dioxide and progresses through the carbon fixation process, includes the biological use of carbon as one of its components.[1]
Types of organism by carbon source
Heterotrophs
Autotrophs
Document 3:::
Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology, and metabolism. Over the last decades of the 20th century, biochemistry has become successful at explaining living processes through these three disciplines. Almost all areas of the life sciences are being uncovered and developed through biochemical methodology and research. Biochemistry focuses on understanding the chemical basis which allows biological molecules to give rise to the processes that occur within living cells and between cells, in turn relating greatly to the understanding of tissues and organs, as well as organism structure and function. Biochemistry is closely related to molecular biology, which is the study of the molecular mechanisms of biological phenomena.
Much of biochemistry deals with the structures, bonding, functions, and interactions of biological macromolecules, such as proteins, nucleic acids, carbohydrates, and lipids. They provide the structure of cells and perform many of the functions associated with life. The chemistry of the cell also depends upon the reactions of small molecules and ions. These can be inorganic (for example, water and metal ions) or organic (for example, the amino acids, which are used to synthesize proteins). The mechanisms used by cells to harness energy from their environment via chemical reactions are known as metabolism. The findings of biochemistry are applied primarily in medicine, nutrition and agriculture. In medicine, biochemists investigate the causes and cures of diseases. Nutrition studies how to maintain health and wellness and also the effects of nutritional deficiencies. In agriculture, biochemists investigate soil and fertilizers, with the goal of improving crop cultivation, crop storage, and pest control. In recent decades, biochemical principles a
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A pre-STEM program is a course of study at any two-year college that prepares a student to transfer to a four-year school to earn a bachelor's degree in a STEM field.
Overview
The concept of a pre-STEM program is being developed to address America's need for more college-trained professionals in science, technology, engineering, and mathematics (STEM). It is an innovation meant to fill a gap at community colleges that do not have 'major' degree paths that students identify with on their way to earning an Associates degree. Students must complete a considerable amount of STEM coursework before transferring from a two-year school to a four-year school and earn a baccalaureate degree in a STEM field. Schools with a pre-STEM program are able to identify those students and support them with STEM-specific academic and career advising, increasing the student's chances of going on to earn a STEM baccalaureate degree in a timely fashion.
With over 50% of America's college-bound students starting their college career at public or private two-year school, and with a very small proportion of students who start college at a two-year school matriculating to and earning STEM degrees from four-year schools, pre-STEM programs have great potential for broadening participation in baccalaureate STEM studies.
Example programs
The effectiveness of pre-STEM programs is being investigated by a consortium of schools in Missouri: Moberly Area Community College, St. Charles Community College, Metropolitan Community College, and Truman State University.
A larger group of schools met at the Belknap Springs Meetings in October 2009 to discuss the challenges and opportunities presented by STEM-focused partnerships between 2-year and 4-year schools. Each program represented a two-year school and a four-year school that were trying to increase the number of people who earn a baccalaureate degree in a STEM area through various means, some of which were pre-STEM programs. Other methods includes
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
The sun’s energy is converted to chemical energy by a what?
A. plant
B. mammal
C. amphibian
D. bacterium
Answer:
|
|
sciq-2978
|
multiple_choice
|
Concentration is the removal of solvent, which increases the concentration of what?
|
[
"vapor",
"Water",
"solute",
"sodium"
] |
C
|
Relavent Documents:
Document 0:::
Dilution is the process of decreasing the concentration of a solute in a solution, usually simply by mixing with more solvent like adding more water to the solution. To dilute a solution means to add more solvent without the addition of more solute. The resulting solution is thoroughly mixed so as to ensure that all parts of the solution are identical.
The same direct relationship applies to gases and vapors diluted in air for example. Although, thorough mixing of gases and vapors may not be as easily accomplished.
For example, if there are 10 grams of salt (the solute) dissolved in 1 litre of water (the solvent), this solution has a certain salt concentration (molarity). If one adds 1 litre of water to this solution, the salt concentration is reduced. The diluted solution still contains 10 grams of salt (0.171 moles of NaCl).
Mathematically this relationship can be shown by equation:
where
c1 = initial concentration or molarity
V1 = initial volume
c2 = final concentration or molarity
V2 = final volume
....
Basic room purge equation
The basic room purge equation is used in industrial hygiene. It determines the time required to reduce a known vapor concentration existing in a closed space to a lower vapor concentration. The equation can only be applied when the purged volume of vapor or gas is replaced with "clean" air or gas. For example, the equation can be used to calculate the time required at a certain ventilation rate to reduce a high carbon monoxide concentration in a room.
Sometimes the equation is also written as:
where
Dt = time required; the unit of time used is the same as is used for Q
V = air or gas volume of the closed space or room in cubic feet, cubic metres or litres
Q = ventilation rate into or out of the room in cubic feet per minute, cubic metres per hour or litres per second
Cinitial = initial concentration of a vapor inside the room measured in ppm
Cfinal = final reduced concentration of the vapor inside the room in ppm
Diluti
Document 1:::
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution.
The extent of the solubility of a substance in a specific solvent is generally measured as the concentration of the solute in a saturated solution, one in which no more solute can be dissolved. At this point, the two substances are said to be at the solubility equilibrium. For some solutes and solvents, there may be no such limit, in which case the two substances are said to be "miscible in all proportions" (or just "miscible").
The solute can be a solid, a liquid, or a gas, while the solvent is usually solid or liquid. Both may be pure substances, or may themselves be solutions. Gases are always miscible in all proportions, except in very extreme situations, and a solid or liquid can be "dissolved" in a gas only by passing into the gaseous state first.
The solubility mainly depends on the composition of solute and solvent (including their pH and the presence of other dissolved substances) as well as on temperature and pressure. The dependency can often be explained in terms of interactions between the particles (atoms, molecules, or ions) of the two substances, and of thermodynamic concepts such as enthalpy and entropy.
Under certain conditions, the concentration of the solute can exceed its usual solubility limit. The result is a supersaturated solution, which is metastable and will rapidly exclude the excess solute if a suitable nucleation site appears.
The concept of solubility does not apply when there is an irreversible chemical reaction between the two substances, such as the reaction of calcium hydroxide with hydrochloric acid; even though one might say, informally, that one "dissolved" the other. The solubility is also not the same as the rate of solution, which is how fast a solid solute dissolves in a liquid solvent. This property de
Document 2:::
Liquid–liquid extraction (LLE), also known as solvent extraction and partitioning, is a method to separate compounds or metal complexes, based on their relative solubilities in two different immiscible liquids, usually water (polar) and an organic solvent (non-polar). There is a net transfer of one or more species from one liquid into another liquid phase, generally from aqueous to organic. The transfer is driven by chemical potential, i.e. once the transfer is complete, the overall system of chemical components that make up the solutes and the solvents are in a more stable configuration (lower free energy). The solvent that is enriched in solute(s) is called extract. The feed solution that is depleted in solute(s) is called the raffinate. LLE is a basic technique in chemical laboratories, where it is performed using a variety of apparatus, from separatory funnels to countercurrent distribution equipment called as mixer settlers. This type of process is commonly performed after a chemical reaction as part of the work-up, often including an acidic work-up.
The term partitioning is commonly used to refer to the underlying chemical and physical processes involved in liquid–liquid extraction, but on another reading may be fully synonymous with it. The term solvent extraction can also refer to the separation of a substance from a mixture by preferentially dissolving that substance in a suitable solvent. In that case, a soluble compound is separated from an insoluble compound or a complex matrix.
From a hydrometallurgical perspective, solvent extraction is exclusively used in separation and purification of uranium and plutonium, zirconium and hafnium, separation of cobalt and nickel, separation and purification of rare earth elements etc., its greatest advantage being its ability to selectively separate out even very similar metals. One obtains high-purity single metal streams on 'stripping' out the metal value from the 'loaded' organic wherein one can precipitate or de
Document 3:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 4:::
In physical chemistry, supersaturation occurs with a solution when the concentration of a solute exceeds the concentration specified by the value of solubility at equilibrium. Most commonly the term is applied to a solution of a solid in a liquid, but it can also be applied to liquids and gases dissolved in a liquid. A supersaturated solution is in a metastable state; it may return to equilibrium by separation of the excess of solute from the solution, by dilution of the solution by adding solvent, or by increasing the solubility of the solute in the solvent.
History
Early studies of the phenomenon were conducted with sodium sulfate, also known as Glauber's Salt because, unusually, the solubility of this salt in water may decrease with increasing temperature. Early studies have been summarised by Tomlinson. It was shown that the crystallization of a supersaturated solution does not simply come from its agitation, (the previous belief) but from solid matter entering and acting as a "starting" site for crystals to form, now called "seeds". Expanding upon this, Gay-Lussac brought attention to the kinematics of salt ions and the characteristics of the container having an impact on the supersaturation state. He was also able to expand upon the number of salts with which a supersaturated solution can be obtained. Later Henri Löwel came to the conclusion that both nuclei of the solution and the walls of the container have a catalyzing effect on the solution that cause crystallization. Explaining and providing a model for this phenomenon has been a task taken on by more recent research. Désiré Gernez contributed to this research by discovering that nuclei must be of the same salt that is being crystallized in order to promote crystallization.
Occurrence and examples
Solid precipitate, liquid solvent
A solution of a chemical compound in a liquid will become supersaturated when the temperature of the saturated solution is changed. In most cases solubility decreases wit
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Concentration is the removal of solvent, which increases the concentration of what?
A. vapor
B. Water
C. solute
D. sodium
Answer:
|
|
sciq-8882
|
multiple_choice
|
A major diversification of what animal group occurred about 50 million years ago, possibly spurred by worldwide climate change?
|
[
"amphibians",
"mammals",
"reptiles",
"insects"
] |
B
|
Relavent Documents:
Document 0:::
The history of life on Earth is closely associated with environmental change on multiple spatial and temporal scales. Climate change is a long-term change in the average weather patterns that have come to define Earth’s local, regional and global climates. These changes have a broad range of observed effects that are synonymous with the term. Climate change is any significant long term change in the expected pattern, whether due to natural variability or as a result of human activity. Predicting the effects that climate change will have on plant biodiversity can be achieved using various models, however bioclimatic models are most commonly used.
Environmental conditions play a key role in defining the function and geographic distributions of plants, in combination with other factors, thereby modifying patterns of biodiversity. Changes in long term environmental conditions that can be collectively coined climate change are known to have had enormous impacts on current plant diversity patterns; further impacts are expected in the future. It is predicted that climate change will remain one of the major drivers of biodiversity patterns in the future. Climate change is thought to be one of several factors causing the currently ongoing human-triggered mass extinction, which is changing the distribution and abundance of many plants.
Palaeo context
The Earth has experienced a constantly changing climate in the time since plants first evolved. In comparison to the present day, this history has seen Earth as cooler, warmer, drier and wetter, and (carbon dioxide) concentrations have been both higher and lower. These changes have been reflected by constantly shifting vegetation, for example forest communities dominating most areas in interglacial periods, and herbaceous communities dominating during glacial periods. It has been shown through fossil records that past climatic change has been a major driver of the processes of speciation and extinction. The best known example
Document 1:::
Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. As of 2022, 2.16 million living animal species have been described—of which around 1.05 million are insects, over 85,000 are molluscs, and around 65,000 are vertebrates. It has been estimated there are around 7.77 million animal species. Animals range in length from to . They have complex interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology.
Most living animal species are in Bilateria, a clade whose members have a bilaterally symmetric body plan. The Bilateria include the protostomes, containing animals such as nematodes, arthropods, flatworms, annelids and molluscs, and the deuterostomes, containing the echinoderms and the chordates, the latter including the vertebrates. Life forms interpreted as early animals were present in the Ediacaran biota of the late Precambrian. Many modern animal phyla became clearly established in the fossil record as marine species during the Cambrian explosion, which began around 539 million years ago. 6,331 groups of genes common to all living animals have been identified; these may have arisen from a single common ancestor that lived 650 million years ago.
Historically, Aristotle divided animals into those with blood and those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa (now synonymous with Animalia) and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on ad
Document 2:::
Roshd Biological Education is a quarterly science educational magazine covering recent developments in biology and biology education for a biology teacher Persian -speaking audience. Founded in 1985, it is published by The Teaching Aids Publication Bureau, Organization for Educational Planning and Research, Ministry of Education, Iran. Roshd Biological Education has an editorial board composed of Iranian biologists, experts in biology education, science journalists and biology teachers.
It is read by both biology teachers and students, as a way of launching innovations and new trends in biology education, and helping biology teachers to teach biology in better and more effective ways.
Magazine layout
As of Autumn 2012, the magazine is laid out as follows:
Editorial—often offering a view of point from editor in chief on an educational and/or biological topics.
Explore— New research methods and results on biology and/or education.
World— Reports and explores on biological education worldwide.
In Brief—Summaries of research news and discoveries.
Trends—showing how new technology is altering the way we live our lives.
Point of View—Offering personal commentaries on contemporary topics.
Essay or Interview—often with a pioneer of a biological and/or educational researcher or an influential scientific educational leader.
Muslim Biologists—Short histories of Muslim Biologists.
Environment—An article on Iranian environment and its problems.
News and Reports—Offering short news and reports events on biology education.
In Brief—Short articles explaining interesting facts.
Questions and Answers—Questions about biology concepts and their answers.
Book and periodical Reviews—About new publication on biology and/or education.
Reactions—Letter to the editors.
Editorial staff
Mohammad Karamudini, editor in chief
History
Roshd Biological Education started in 1985 together with many other magazines in other science and art. The first editor was Dr. Nouri-Dalooi, th
Document 3:::
This article is a list of biological species, subspecies, and evolutionary significant units that are known to have become extinct during the Holocene, the current geologic epoch, ordered by their known or approximate date of disappearance from oldest to most recent.
The Holocene is considered to have started with the Holocene glacial retreat around 11650 years Before Present ( BC). It is characterized by a general trend towards global warming, the expansion of anatomically modern humans (Homo sapiens) to all emerged land masses, the appearance of agriculture and animal husbandry, and a reduction in global biodiversity. The latter, dubbed the sixth mass extinction in Earth history, is largely attributed to increased human population and activity, and may have started already during the preceding Pleistocene epoch with the demise of the Pleistocene megafauna.
The following list is incomplete by necessity, since the majority of extinctions are thought to be undocumented, and for many others there isn't a definitive, widely accepted last, or most recent record. According to the species-area theory, the present rate of extinction may be up to 140,000 species per year.
10th millennium BC
9th millennium BC
8th millennium BC
7th millennium BC
6th millennium BC
5th millennium BC
4th millennium BC
3rd millennium BC
2nd millennium BC
1st millennium BC
1st millennium CE
1st–5th centuries
6th–10th centuries
2nd millennium CE
11th-12th century
13th-14th century
15th-16th century
17th century
18th century
19th century
1800s-1820s
1830s-1840s
1850s-1860s
1870s
1880s
1890s
20th century
1900s
1910s
1920s
1930s
1940s
1950s
1960s
1970s
1980s
1990s
3rd millennium CE
21st century
2000s
2010s
See also
List of extinct animals
Extinction event
Quaternary extinction event
Holocene extinction
Timeline of the evolutionary history of life
Timeline of environmental history
Index of environmental articles
List of environmental issues
Document 4:::
The Encyclopedia of Life (EOL) is a free, online encyclopedia intended to document all of the 1.9 million living species known to science. It is compiled from existing trusted databases curated by experts and with the assistance of non-experts throughout the world. It aims to build one "infinitely expandable" page for each species, including video, sound, images, graphics, as well as text. In addition, the Encyclopedia incorporates content from the Biodiversity Heritage Library, which digitizes millions of pages of printed literature from the world's major natural history libraries. The project was initially backed by a US$50 million funding commitment, led by the MacArthur Foundation and the Sloan Foundation, who provided US$20 million and US$5 million, respectively. The additional US$25 million came from five cornerstone institutions—the Field Museum, Harvard University, the Marine Biological Laboratory, the Missouri Botanical Garden, and the Smithsonian Institution. The project was initially led by Jim Edwards and the development team by David Patterson. Today, participating institutions and individual donors continue to support EOL through financial contributions.
Overview
EOL went live on 26 February 2008 with 30,000 entries. The site immediately proved to be extremely popular, and temporarily had to revert to demonstration pages for two days when over 11 million views of it were requested.
The site relaunched on 5 September 2011 with a redesigned interface and tools. The new version – referred to as EOLv2 – was developed in response to requests from the general public, citizen scientists, educators and professional biologists for a site that was more engaging, accessible and personal. EOLv2 is redesigned to enhance usability and encourage contributions and interactions among users. It is also internationalized with interfaces provided for English, German, Spanish, French, Galician, Serbian, Macedonian, Arabic, Chinese, Korean and Ukrainian language speakers
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
A major diversification of what animal group occurred about 50 million years ago, possibly spurred by worldwide climate change?
A. amphibians
B. mammals
C. reptiles
D. insects
Answer:
|
|
sciq-1224
|
multiple_choice
|
Why does neptune's appearance change?
|
[
"the seasons",
"turbulent atmosphere",
"the speed of rotation",
"the changing orbit"
] |
B
|
Relavent Documents:
Document 0:::
This article is a list of notable unsolved problems in astronomy. Some of these problems are theoretical, meaning that existing theories may be incapable of explaining certain observed phenomena or experimental results. Others are experimental, meaning that experiments necessary to test proposed theory or investigate a phenomenon in greater detail have not yet been performed. Some pertain to unique events or occurrences that have not repeated themselves and whose causes remain unclear.
Planetary astronomy
Our solar system
Orbiting bodies and rotation:
Are there any non-dwarf planets beyond Neptune?
Why do extreme trans-Neptunian objects have elongated orbits?
Rotation rate of Saturn:
Why does the magnetosphere of Saturn rotate at a rate close to that at which the planet's clouds rotate?
What is the rotation rate of Saturn's deep interior?
Satellite geomorphology:
What is the origin of the chain of high mountains that closely follows the equator of Saturn's moon, Iapetus?
Are the mountains the remnant of hot and fast-rotating young Iapetus?
Are the mountains the result of material (either from the rings of Saturn or its own ring) that over time collected upon the surface?
Extra-solar
How common are Solar System-like planetary systems? Some observed planetary systems contain Super-Earths and Hot Jupiters that orbit very close to their stars. Systems with Jupiter-like planets in Jupiter-like orbits appear to be rare. There are several possibilities why Jupiter-like orbits are rare, including that data is lacking or the grand tack hypothesis.
Stellar astronomy and astrophysics
Solar cycle:
How does the Sun generate its periodically reversing large-scale magnetic field?
How do other Sol-like stars generate their magnetic fields, and what are the similarities and differences between stellar activity cycles and that of the Sun?
What caused the Maunder Minimum and other grand minima, and how does the solar cycle recover from a minimum state?
Coronal heat
Document 1:::
In astronomy, a disrupted planet is a planet or exoplanet or, perhaps on a somewhat smaller scale, a planetary-mass object, planetesimal, moon, exomoon or asteroid that has been disrupted or destroyed by a nearby or passing astronomical body or object such as a star. Necroplanetology is the related study of such a process.
The result of such a disruption may be the production of excessive amounts of related gas, dust and debris, which may eventually surround the parent star in the form of a circumstellar disk or debris disk. As a consequence, the orbiting debris field may be an "uneven ring of dust", causing erratic light fluctuations in the apparent luminosity of the parent star, as may have been responsible for the oddly flickering light curves associated with the starlight observed from certain variable stars, such as that from Tabby's Star (KIC 8462852), RZ Piscium and WD 1145+017. Excessive amounts of infrared radiation may be detected from such stars, suggestive evidence in itself that dust and debris may be orbiting the stars.
Examples
Planets
Examples of planets, or their related remnants, considered to have been a disrupted planet, or part of such a planet, include: ‘Oumuamua and WD 1145+017 b, as well as asteroids, hot Jupiters and those that are hypothetical planets, like Fifth planet, Phaeton, Planet V and Theia.
Stars
Examples of parent stars considered to have disrupted a planet include: EPIC 204278916, Tabby's Star (KIC 8462852), PDS 110, RZ Piscium, WD 1145+017 and 47 Ursae Majoris.
Tabby's Star light curve
Tabby's Star (KIC 8462852) is an F-type main-sequence star exhibiting unusual light fluctuations, including up to a 22% dimming in brightness. Several hypotheses have been proposed to explain these irregular changes, but none to date fully explain all aspects of the curve. One explanation is that an "uneven ring of dust" orbits Tabby's Star. However, in September 2019, astronomers reported that the observed dimmings of Tabby's Star may ha
Document 2:::
Planetary migration occurs when a planet or other body in orbit around a star interacts with a disk of gas or planetesimals, resulting in the alteration of its orbital parameters, especially its semi-major axis. Planetary migration is the most likely explanation for hot Jupiters (exoplanets with Jovian masses but orbits of only a few days). The generally accepted theory of planet formation from a protoplanetary disk predicts that such planets cannot form so close to their stars, as there is insufficient mass at such small radii and the temperature is too high to allow the formation of rocky or icy planetesimals.
It has also become clear that terrestrial-mass planets may be subject to rapid inward migration if they form while the gas disk is still present. This may affect the formation of the cores of the giant planets (which have masses of the order of 10 to 1000 Earth masses), if those planets form via the core-accretion mechanism.
Types of disk
Gas disk
Observations suggest that gas in protoplanetary disks orbiting young stars have lifetimes of a few to several million years. If planets with masses of around an Earth mass or greater form while the gas is still present, the planets can exchange angular momentum with the surrounding gas in the protoplanetary disk so that their orbits change gradually. Although the sense of migration is typically inwards in locally isothermal disks, outward migration may occur in disks that possess entropy gradients.
Planetesimal disk
During the late phase of planetary system formation, massive protoplanets and planetesimals gravitationally interact in a chaotic manner causing many planetesimals to be thrown into new orbits. This results in angular-momentum exchange between the planets and the planetesimals, and leads to migration (either inward or outward). Outward migration of Neptune is believed to be responsible for the resonant capture of Pluto and other Plutinos into the 3:2 resonance with Neptune.
Types of migrati
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For the first time the South Pole of Jupiter was photographed in detail by the Juno spacecraft, which arrived to Jupiter in July 2016 and for the first time in history entered the polar orbit of Jupiter. At the same time, six cyclones were discovered at the South Pole: Оne in the center and five around it (their centers formed a close to regular pentagon), each about 4,500 km (2,800 mi.) in diameter, with a wind speed of about 360 km/h (220 mph), and all of them twisted clockwise. A similar picture at the North Pole of Jupiter presents nine cyclones of similar size: one in the center, and eight around it, rotating counterclockwise.
For more than three years the structure of cyclones at both poles of the nearest to us gas giant remained stable, but on November 3, 2019, on the 22nd rotation, "Juno" found the birth of a new cyclone at the South Pole: it quickly "pushed" the previous (although still has a smaller size, about 800 km), and now the centers of peripheral cyclones pole form almost right 6-corner.
Before Juno, only the Galileo probe entered Jupiter's orbit from 1995 to 2003; however, its orbital inclination made it impossible to observe the polar regions of Jupiter; Cassini, which flew past Jupiter in 2000, also had no opportunity to photograph the polar regions. Thus, they remained "white spots" until 2016 (the images of the previous flyby missions and Earth telescopes had low resolution); however, back in 2000, the polar X-ray spots of Jupiter (the southern one is significantly weaker than the northern one) were detected.
Jupiter's geographic South Pole is also the location of its magnetic South Pole (Jupiter does not have a well-defined magnetic North Pole).
Document 4:::
Neptune trojans are bodies that orbit the Sun near one of the stable Lagrangian points of Neptune, similar to the trojans of other planets. They therefore have approximately the same orbital period as Neptune and follow roughly the same orbital path. Thirty-one Neptune trojans are currently known, of which 27 orbit near the Sun–Neptune Lagrangian point 60° ahead of Neptune and four orbit near Neptune's region 60° behind Neptune. The Neptune trojans are termed 'trojans' by analogy with the Jupiter trojans.
The discovery of in a high-inclination (>25°) orbit was significant, because it suggested a "thick" cloud of trojans (Jupiter trojans have inclinations up to 40°), which is indicative of freeze-in capture instead of in situ or collisional formation. It is suspected that large (radius ≈ 100 km) Neptune trojans could outnumber Jupiter trojans by an order of magnitude.
In 2010, the discovery of the first known Neptune trojan, , was announced. Neptune's trailing region is currently very difficult to observe because it is along the line of sight to the center of the Milky Way, an area of the sky crowded with stars.
Discovery and exploration
In 2001, the first Neptune trojan was discovered, , near Neptune's region, and with it the fifth known populated stable reservoir of small bodies in the Solar System. In 2005, the discovery of the high-inclination trojan has indicated that the Neptune trojans populate thick clouds, which has constrained their possible origins (see below).
On August 12, 2010, the first trojan, , was announced. It was discovered by a dedicated survey that scanned regions where the light from the stars near the Galactic Center is obscured by dust clouds. This suggests that large trojans are as common as large trojans, to within uncertainty, further constraining models about their origins (see below).
It would have been possible for the New Horizons spacecraft to investigate Neptune trojans discovered by 2014, when it passed through this
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Why does neptune's appearance change?
A. the seasons
B. turbulent atmosphere
C. the speed of rotation
D. the changing orbit
Answer:
|
|
sciq-1835
|
multiple_choice
|
Rising and falling levels of what will result in progression of the ovarian and menstrual cycles?
|
[
"hormones",
"blood pressure",
"red blood cells",
"oxygen"
] |
A
|
Relavent Documents:
Document 0:::
The reproductive-cell cycle theory posits that the hormones that regulate reproduction act in an antagonistic pleiotrophic manner to control aging via cell cycle signaling; promoting growth and development early in life in order to achieve reproduction, but later in life, in a futile attempt to maintain reproduction, become dysregulated and drive senescence. Rather than seeing aging as a loss of functionality as we get older, this theory defines aging as any change in an organism over time, as evidenced by the fact that if all chemical reactions in the body were stopped, no change, and thus no aging, would occur. Since the most important change in an organism through time is the chemical reactions that result in a single cell developing into a multicellular organism, whatever controls these chemical reactions that regulate cell growth, development, and death, is believed to control aging. The theory argues that these cellular changes are directed by reproductive hormones of the hypothalamic-pituitary-gonadal axis (HPG axis). Receptors for reproductive hormones (such as estrogens, progestogens, androgens and gonadotropins) have been found to be present in all tissues of the body. Thus, HPG axis hormones normally promote growth and development of the organism early in life in order to achieve reproduction. Hormones levels then begin to change in men around age 30 and more abruptly in women when they reach menopause, around age 50. When the HPG axis becomes unbalanced, cellular growth and development is dysregulated, and cell death and dysfunction can occur, both of which can initiate senescence, the accumulated damage to cells, tissues, and organs that occurs with the passage of time and that is associated with functional loss during aging.
Evidence supporting this theory comes from disease studies showing that women who reach menopause later have less heart disease and stroke, less dementia, and less osteoporosis, supporting the theory that the longer the HPG a
Document 1:::
Seed cycling is the rotation of different edible seeds into the diet at different times in the menstrual cycle. Practitioners believe that since some seeds promote estrogen production, and others promote progesterone production, that eating these seeds in the correct parts of the menstrual cycle will balance the hormonal rhythm.
There is no scientific evidence to support the belief that cycling the seeds actually regulates the hormonal rhythm, but the practice is probably harmless.
Overview
Seed cycling advocates note that the menstrual cycle is broken up into four interconnected phases. The first phase is menstruation, followed by the follicular phase, then ovulation, then the luteal phase.
Assuming a 28-day cycle, the first 13 days represent the menstrual and follicular phases, in which day 1 is when menstruation begins. During day-13, the seed cycling diet suggests consuming either flax or pumpkin seeds daily to boost estrogen, which helps support these phases and the move towards ovulation.
Days 14-28 represent the ovulatory phase and luteal phase, with ovulation around day 14. The seed cycling diet suggests sesame or sunflower seeds to boost progesterone at this time, ground up to increase the surface area for absorption of the essential fatty acids, minerals, and other nutrients.
The seed cycling diet relies on the belief that most women have a 28-day cycle. However, only 10-15% of women have 28-30 day cycles; most women's cycles vary, or run longer or shorter. For women with irregular or absent cycle, menopause, or post-menopause, the seed cycling diet suggests starting the seed cycle with any two weeks, and then rotating. However, many women who track their cycles through symptothermal methods (e.g. Basal Body Temperature and cervical mucus) are able to adapt the seed cycling protocol to their individual cycle and therefore do not need to rely on the belief that women have 28-day cycles.
Research
There is currently a lack of solid scientific eviden
Document 2:::
Involution is the shrinking or return of an organ to a former size. At a cellular level, involution is characterized by the process of proteolysis of the basement membrane (basal lamina), leading to epithelial regression and apoptosis, with accompanying stromal fibrosis. The consequent reduction in cell number and reorganization of stromal tissue leads to the reduction in the size of the organ.
Examples
Thymus
The thymus continues to grow between birth and puberty and then begins to atrophy, a process directed by the high levels of circulating sex hormones. Proportional to thymic size, thymic activity (T cell output) is most active before puberty. Upon atrophy, the size and activity are dramatically reduced, and the organ is primarily replaced with fat. The atrophy is due to the increased circulating level of sex hormones, and chemical or physical castration of an adult results in the thymus increasing in size and activity.
Uterus
Involution is the process by which the uterus is transformed from pregnant to non-pregnant state. This period is characterized by the restoration of ovarian function in order to prepare the body for a new pregnancy. It is a physiological process occurring after parturition; the hypertrophy of the uterus has to be undone since it does not need to house the fetus anymore. This process is primarily due to the hormone oxytocin. The completion of this period is defined as when the diameter of the uterus returns to the size it is normally during a woman's menstrual cycle.
Mammary gland
During pregnancy until after birth, mammary glands grow steadily to a size required for optimal milk production. At the end of breastfeeding, the number of cells in the mammary gland becomes reduced until approximately the same number is reached as before the start of pregnancy.
See also
Subinvolution
Document 3:::
Although the process is similar in many animals, this article will deal exclusively with human folliculogenesis.
In biology, folliculogenesis is the maturation of the ovarian follicle, a densely packed shell of somatic cells that contains an immature oocyte. Folliculogenesis describes the progression of a number of small primordial follicles into large preovulatory follicles that occurs in part during the menstrual cycle.
Contrary to male spermatogenesis, which can last indefinitely, folliculogenesis ends when the remaining follicles in the ovaries are incapable of responding to the hormonal cues that previously recruited some follicles to mature. This depletion in follicle supply signals the beginning of menopause.
Overview
The primary role of the follicle is oocyte support. From the whole pool of follicles a woman is born with, only 0.1% of them will rise ovulation, whereas 99.9% will break down (in a process called follicular atresia). From birth, the ovaries of the human female contain a number of immature, primordial follicles. These follicles each contain a similarly immature primary oocyte. At puberty, clutches of follicles begin folliculogenesis, entering a growth pattern that ends in ovulation (the process where the oocyte leaves the follicle) or in atresia (death of the follicle's granulosa cells).
During follicular development, primordial follicles undergo a series of critical changes in character, both histologically and hormonally. First they change into primary follicles and later into secondary follicles. The follicles then transition to tertiary, or antral, follicles. At this stage in development, they become dependent on hormones, particularly FSH which causes a substantial increase in their growth rate. The late tertiary or pre-ovulatory follicle ruptures and discharges the oocyte (that has become a secondary oocyte), ending folliculogenesis.
Follicle ‘selection’ is the process by which a single ‘dominant’ follicle is chosen from the recruited
Document 4:::
Menopause in the workplace is a social and human resources campaigning issue in which people work to raise awareness of the impact menopause symptoms can have on attendance and performance in the workplace.
Activism
Campaigners, journalists, personnel professionals and academics draw upon published research and lobby for support for workers via industrial trades unions (including ACAS TUC UCU UNISON EIS, NASUTW ) and changes in legislation. In the UK under the Equality Act 2010, menopause discrimination is covered by three of the protected characteristics: age, sex and disability discrimination. A UK government cross-party equalities working group explored why workplaces were failing women going through the menopause
Background
The average age for the menopause transition is 51. Women over the age of 50 are a growing demographic in the workforce. 14 million working days are lost to menopause each year in the UK. Around 900,000 women have left jobs in the UK because of menopause symptoms making continuing work impossible.
Many women go through the menopause during their working lives, and workplace support is vital. Menopause is considered by many to be a private matter or ‘a women's issue' or the 'last taboo' subject in workplaces. The TUC found that many employers were unaware of the issues involved and not tackling problems in ways that helped workers. The impact of employers failing to make reasonable adjustments include loss of work days due to absence and women being disciplined on competency grounds for health issues. The number of UK employment tribunals concerning menopause is increasing
A UK government report suggests that employers can make positive changes by "changing organisational cultures; compulsory equality and diversity training; providing specialist advice; tailored absence policies; flexible working patterns for mid-life women; and fairly low cost environmental changes" to cater for women's differing experiences. The CIPD have prod
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Rising and falling levels of what will result in progression of the ovarian and menstrual cycles?
A. hormones
B. blood pressure
C. red blood cells
D. oxygen
Answer:
|
|
sciq-2854
|
multiple_choice
|
The most important characteristic of extant amphibians is a moist, permeable skin used for this?
|
[
"cutaneous respiration",
"avian respiration",
"simple respiration",
"benign respiration"
] |
A
|
Relavent Documents:
Document 0:::
Batrachology is the branch of zoology concerned with the study of amphibians including frogs and toads, salamanders, newts, and caecilians. It is a sub-discipline of herpetology, which also includes non-avian reptiles (snakes, lizards, amphisbaenids, turtles, terrapins, tortoises, crocodilians, and the tuatara). Batrachologists may study the evolution, ecology, ethology, or anatomy of amphibians.
Amphibians are cold blooded vertebrates largely found in damp habitats although many species have special behavioural adaptations that allow them to live in deserts, trees, underground and in regions with wide seasonal variations in temperature. There are over 7250 species of amphibians.
Notable batrachologists
Jean Marius René Guibé
Gabriel Bibron
Oskar Boettger
George Albert Boulenger
Edward Drinker Cope
François Marie Daudin
Franz Werner
Leszek Berger
Document 1:::
The feet of geckos have a number of specializations. Their surfaces can adhere to any type of material with the exception of Teflon (PTFE). This phenomenon can be explained with three elements:
Foot structure
Structure of the material to which the foot adheres
The ability to adhere to a surface and become a part of it
Background
Geckos are members of the family Gekkonidae. They are reptiles that inhabit temperate and tropical regions. There are over 1,000 different species of geckos. They can be a variety of colors. Geckos are omnivorous, feeding on a variety of foods, including insects and worms. Most gecko species, including the crested gecko (Correlophus ciliatus), can climb walls and other surfaces.
Structure
Chemical structure
The interactions between the gecko's feet and the climbing surface are stronger than simple surface area effects. On its feet, the gecko has many microscopic hairs, or setae (singular seta), that increase the Van der Waals forces - the distance-dependent attraction between atoms or molecules - between its feet and the surface. These setae are fibrous structural proteins that protrude from the epidermis, which is made of β-keratin, Similar to α-keratin being the basic building block of human skin and finger nails.
Physical structure
The bottom surface of a gecko's foot will consist of millions of hairy structures called setae. These setae are 5 mm long and are thinner than a human hair. There are thousands of tiny structures called spatula on every seta. Geckos create Van der Waals force by making contact with the surface of materials using their spatulas. More spatulas implies more surface area. The spatulas have sharp edges, which on application of stress in a specific angle, bends and creates more contact with the surface in order to climb on them vertically. Thus, more contact with the surface creates more Van der Waals force to support the whole body of the creature. One seta can hold weights up to 20 mg using Van der Waals fo
Document 2:::
Roshd Biological Education is a quarterly science educational magazine covering recent developments in biology and biology education for a biology teacher Persian -speaking audience. Founded in 1985, it is published by The Teaching Aids Publication Bureau, Organization for Educational Planning and Research, Ministry of Education, Iran. Roshd Biological Education has an editorial board composed of Iranian biologists, experts in biology education, science journalists and biology teachers.
It is read by both biology teachers and students, as a way of launching innovations and new trends in biology education, and helping biology teachers to teach biology in better and more effective ways.
Magazine layout
As of Autumn 2012, the magazine is laid out as follows:
Editorial—often offering a view of point from editor in chief on an educational and/or biological topics.
Explore— New research methods and results on biology and/or education.
World— Reports and explores on biological education worldwide.
In Brief—Summaries of research news and discoveries.
Trends—showing how new technology is altering the way we live our lives.
Point of View—Offering personal commentaries on contemporary topics.
Essay or Interview—often with a pioneer of a biological and/or educational researcher or an influential scientific educational leader.
Muslim Biologists—Short histories of Muslim Biologists.
Environment—An article on Iranian environment and its problems.
News and Reports—Offering short news and reports events on biology education.
In Brief—Short articles explaining interesting facts.
Questions and Answers—Questions about biology concepts and their answers.
Book and periodical Reviews—About new publication on biology and/or education.
Reactions—Letter to the editors.
Editorial staff
Mohammad Karamudini, editor in chief
History
Roshd Biological Education started in 1985 together with many other magazines in other science and art. The first editor was Dr. Nouri-Dalooi, th
Document 3:::
Myomeres are blocks of skeletal muscle tissue arranged in sequence, commonly found in aquatic chordates. Myomeres are separated from adjacent myomeres by connective fascia (myosepta) and most easily seen in larval fishes or in the olm. Myomere counts are sometimes used for identifying specimens, since their number corresponds to the number of vertebrae in the adults. Location varies, with some species containing these only near the tails, while some have them located near the scapular or pelvic girdles. Depending on the species, myomeres could be arranged in an epaxial or hypaxial manner. Hypaxial refers to ventral muscles and related structures while epaxial refers to more dorsal muscles. The horizontal septum divides these two regions in vertebrates from cyclostomes to gnathostomes. In terrestrial chordates, the myomeres become fused as well as indistinct, due to the disappearance of myosepta.
Shape
The shape of myomeres varies by species. Myomeres are commonly zig-zag, "V" (lancelets), "W" (fishes), or straight (tetrapods)– shaped muscle fibers. Generally, cyclostome myomeres are arranged in vertical strips while those of jawed fishes are folded in a complex matter due to swimming capability evolution. Specifically, myomeres of elasmobranchs and eels are “W”-shaped. Contrastingly, myomeres of tetrapods run vertically and do not display complex folding. Another species with simply-lain myomeres are mudpuppies. Myomeres overlap each other in succession, meaning myomere activation also allows neighboring myomeres to activate.
Myomeres are made up of myoglobin-rich dark muscle as well as white muscle. Dark muscle, generally, functions as slow-twitch muscle fibers while white muscle is composed of fast-twitch fibers.
Function
Specifically, three types of myomeres in fish-like chordates include amphioxine (lancelet), cyclostomine (jawless fish), and gnathostomine (jawed fish). A common function shared by all of these is that they function to flex the body lateral
Document 4:::
The common frog or grass frog (Rana temporaria), also known as the European common frog, European common brown frog, European grass frog, European Holarctic true frog, European pond frog or European brown frog, is a semi-aquatic amphibian of the family Ranidae, found throughout much of Europe as far north as Scandinavia and as far east as the Urals, except for most of the Iberian Peninsula, southern Italy, and the southern Balkans. The farthest west it can be found is Ireland. It is also found in Asia, and eastward to Japan. The nominative, and most common, subspecies Rana temporaria temporaria is a largely terrestrial frog native to Europe. It is distributed throughout northern Europe and can be found in Ireland, the Isle of Lewis and as far east as Japan.
Common frogs metamorphose through three distinct developmental life stages — aquatic larva, terrestrial juvenile, and adult. They have corpulent bodies with a rounded snout, webbed feet and long hind legs adapted for swimming in water and hopping on land. Common frogs are often confused with the common toad (Bufo bufo), but frogs can easily be distinguished as they have longer legs, hop, and have a moist skin, whereas toads crawl and have a dry 'warty' skin. The spawn of the two species also differs, in that frog spawn is laid in clumps and toad spawn is laid in long strings.
There are 3 subspecies of the common frog, R. t. temporaria, R. t. honnorati and R. t. palvipalmata. R. t. temporaria is the most common subspecies of this frog.
Description
The adult common frog has a body length of . In addition, its back and flanks vary in colour from olive green to grey-brown, brown, olive brown, grey, yellowish and rufous. However, it can lighten and darken its skin to match its surroundings. Some individuals have more unusual colouration—both black and red individuals have been found in Scotland, and albino frogs have been found with yellow skin and red eyes. During the mating season the male common frog tends to tu
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
The most important characteristic of extant amphibians is a moist, permeable skin used for this?
A. cutaneous respiration
B. avian respiration
C. simple respiration
D. benign respiration
Answer:
|
|
sciq-9202
|
multiple_choice
|
In mammals, sound waves are collected by the external, cartilaginous part of the ear called the pinna, then travel through the auditory canal and cause vibration of the thin diaphragm called the tympanum or this?
|
[
"head drum",
"microphone drum",
"speaker drum",
"ear drum"
] |
D
|
Relavent Documents:
Document 0:::
The torus semicircularis is a region of the vertebrate midbrain that contributes to auditory perception, studied most often in fish and amphibians. Neurons from the medulla project to the nucleus centralis and the nucleus ventrolateralis in the torus semicircularis, providing afferent auditory and hydrodynamic information. Research suggests that these nuclei interact with each other, suggesting that this area of the brain is bimodally sensitive. In the Gymnotiform fish, which are weakly electric fish, the torus semicircularis was observed to exhibit laminar organization. It receives afferent input, specifically electrosensory, mechanical, and auditory stimuli. In frogs, researchers have studied how neurons in the torus semicircularis prefer certain characteristics of sound differentially. Single neurons fire selectively based on the auditory parameters of a stimulus. Functionally, this can allow members of a species to distinguish whether a call is of the same (conspecific) or a different species. This has been observed to play a role in mate selection. In the Tungara frog, which produces a species-specific mating call, scientists studied responses in the laminar nucleus of the torus semicircularis to various parts of the call. They came to the conclusion that this part of the brain acts as a feature detector (a neuron/neurons that respond to a certain feature of a stimulus) for the parts of the auditory stimulus that are conspecific. From an evolutionary standpoint, research has been conducted in turtles to connect the distribution of calcium-binding proteins in the torus semicircularis among birds and mammals to a common reptile predecessor.
Document 1:::
Animal song is not a well-defined term in scientific literature, and the use of the more broadly defined term vocalizations is in more common use. Song generally consists of several successive vocal sounds incorporating multiple syllables. Some sources distinguish between simpler vocalizations, termed “calls”, reserving the term “song” for more complex productions. Song-like productions have been identified in several groups of animals, including cetaceans (whales and dolphins), avians (birds), anurans (frogs), and humans. Social transmission of song has been found in groups including birds and cetaceans.
Anatomy of sound production
Mammals
Most mammalian species produce sound by passing air from the lungs across the larynx, vibrating the vocal folds. Sound then enters the supralaryngeal vocal tract, which can be adjusted to produce various changes in sound output, providing refinement of vocalizations. Although morphological differences between species affect production of sound, neural control is thought to be more essential factor in producing the variations within human speech and song compared to those of other mammals. Cetacean vocalizations are an exception to this general mechanism. Toothed whales (Odontocetes) pass air through a system of air sacs and muscular phonic lips, which vibrate to produce audible vocalizations, thus serving the function of vocal folds in other mammals. Sound vibrations are conveyed to an organ in the head called the melon, which can be changed in shape to control and direct vocalizations. Unlike in humans and other mammals, toothed whales are able to recycle air used in vocal production, allowing whales to sing without releasing air. Some cetaceans, such as humpback whales, sing continuously for hours.
Anurans
Like mammals, anurans possess a larynx and vocal folds, which are used to create vibrations in sound production. However, frogs also use structures called vocal sacs, elastic membranes in the base of the mouth which in
Document 2:::
Sound localization is a listener's ability to identify the location or origin of a detected sound in direction and distance.
The sound localization mechanisms of the mammalian auditory system have been extensively studied. The auditory system uses several cues for sound source localization, including time difference and level difference (or intensity difference) between the ears, and spectral information. These cues are also used by other animals, such as birds and reptiles, but there may be differences in usage, and there are also localization cues which are absent in the human auditory system, such as the effects of ear movements. Animals with the ability to localize sound have a clear evolutionary advantage.
How sound reaches the brain
Sound is the perceptual result of mechanical vibrations traveling through a medium such as air or water. Through the mechanisms of compression and rarefaction, sound waves travel through the air, bounce off the pinna and concha of the exterior ear, and enter the ear canal. The sound waves vibrate the tympanic membrane (ear drum), causing the three bones of the middle ear to vibrate, which then sends the energy through the oval window and into the cochlea where it is changed into a chemical signal by hair cells in the organ of Corti, which synapse onto spiral ganglion fibers that travel through the cochlear nerve into the brain.
Neural interactions
In vertebrates, interaural time differences are known to be calculated in the superior olivary nucleus of the brainstem. According to Jeffress, this calculation relies on delay lines: neurons in the superior olive which accept innervation from each ear with different connecting axon lengths. Some cells are more directly connected to one ear than the other, thus they are specific for a particular interaural time difference. This theory is equivalent to the mathematical procedure of cross-correlation. However, because Jeffress's theory is unable to account for the precedence effect,
Document 3:::
The tympanic part of the temporal bone is a curved plate of bone lying below the squamous part of the temporal bone, in front of the mastoid process, and surrounding the external part of the ear canal.
It originates as a separate bone (tympanic bone), which in some mammals stays separate through life.
Evolutionarily, a portion of it is derived from the angular bone of the reptilian lower jaw.
Surfaces
Its postero-superior surface is concave, and forms the anterior wall, the floor, and part of the posterior wall of the bony ear canal.
Medially, it presents a narrow furrow, the tympanic sulcus, for the attachment of the tympanic membrane.
Its antero-inferior surface is quadrilateral and slightly concave; it constitutes the posterior boundary of the mandibular fossa, and is in contact with the retromandibular part of the parotid gland.
Borders
Its lateral border is free and rough, and gives attachment to the cartilaginous part of the ear canal. Internally, the tympanic part is fused with the petrous portion, and appears in the retreating angle between it and the squama, where it lies below and lateral to the orifice of the auditory tube. Posteriorly, it blends with the squama and mastoid part, and forms the anterior boundary of the tympanomastoid fissure.
Its upper border fuses laterally with the back of the postglenoid process, while medially it bounds the petrotympanic fissure.
The medial part of the lower border is thin and sharp; its lateral part splits to enclose the root of the styloid process, and is therefore named the vaginal process.
Ear canal
The central portion of the tympanic part is thin, as it gives rise to the bony inner two-thirds of the ear canal, and in 5 - 20% of skulls the lower surface is perforated by a hole, the foramen of Huschke that opens onto the temporomandibular joint due to incomplete fusion of the anterior and posterior prominences during development.
The bony portion of the ear canal is nearly 2 cm long and is directed inwa
Document 4:::
In the ventral cochlear nucleus (VCN), auditory nerve fibers enter the brain via the nerve root in the VCN. The ventral cochlear nucleus is divided into the anterior ventral (anteroventral) cochlear nucleus (AVCN) and the posterior ventral (posteroventral) cochlear nucleus (PVCN). In the VCN, auditory nerve fibers bifurcate, the ascending branch innervates the AVCN and the descending branch innervates the PVCN and then continue to the dorsal cochlear nucleus. The orderly innervation by auditory nerve fibers gives the AVCN a tonotopic organization along the dorsoventral axis. Fibers that carry information from the apex of the cochlea that are tuned to low frequencies contact neurons in the ventral part of the AVCN; those that carry information from the base of the cochlea that are tuned to high frequencies contact neurons in the dorsal part of the AVCN. Several populations of neurons populate the AVCN. Bushy cells receive input from auditory nerve fibers through particularly large endings called end bulbs of Held. They contact stellate cells through more conventional boutons.
Cell types
The anterior cochlear nucleus contains several cell types, which correspond fairly well with different physiological unit types. Additionally, these cell types generally have specific projection patterns.
Bushy cells
Named due to the branching, tree-like, nature of their dendritic fields, visible using Golgi's method, they receive large end bulbs of Held from auditory nerve fibers. Bushy cells are of three subtypes that project to different target nuclei in the superior olivary complex.
Globular
Globular bushy cells project large axons to the contralateral medial nucleus of the trapezoid body (MNTB), in the superior olivary complex where they synapse onto principal cells via a single calyx of Held, and several smaller collaterals synapse ipsilaterally in the posterior (PPO) and dorsolateral periolivary (DLPO) nuclei, lateral superior olive (LSO), and lateral nucleus of the tra
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
In mammals, sound waves are collected by the external, cartilaginous part of the ear called the pinna, then travel through the auditory canal and cause vibration of the thin diaphragm called the tympanum or this?
A. head drum
B. microphone drum
C. speaker drum
D. ear drum
Answer:
|
|
sciq-7651
|
multiple_choice
|
What type of isotopes have short half-lives and are given in very low doses?
|
[
"gasses",
"stable isotopes",
"radioisotopes",
"radionuclides"
] |
C
|
Relavent Documents:
Document 0:::
A medical isotope is an isotope used in medicine.
The first uses of isotopes in medicine were in radiopharmaceuticals, and this is still the most common use. However more recently, separated stable isotopes have also come into use.
Examples of non-radioactive medical isotopes are:
Deuterium in deuterated drugs
Carbon-13 used in liver function and metabolic tests
Radioactive isotopes used
Radioactive isotopes are used in medicine for both treatment and diagnostic scans. The most common isotope used in diagnostic scans is Tc-99m (Technetium-99m), being used in approximately 85% of all nuclear medicine diagnostic scans worldwide. It is used for diagnoses involving a large range of body parts and diseases such as cancers and neurological problems. Another well-known radioactive isotope used in medicine is I-131 (Iodine-131), which is used as a radioactive label for some radiopharmaceutical therapies or the treatment of some types of thyroid cancer.
Document 1:::
CERN-MEDical Isotopes Collected from ISOLDE (MEDICIS) is a facility located in the Isotope Separator Online DEvice (ISOLDE) facility at CERN, designed to produce high-purity isotopes for developing the practice of patient diagnosis and treatment. The facility was initiated in 2010, with its first radioisotopes (terbium-155) produced on 12 December 2017.
The target used to produce radioactive nuclei at the ISOLDE facility only absorbs 10% of the proton beam. MEDICIS positions a second target behind the first, which is irradiated by the leftover 90% of the proton beam. The target is then moved to an off-line mass separation system and isotopes are extracted from the target. These isotopes are implanted in metallic foil and can be delivered to research facilities and hospitals.
MEDICIS is a nuclear class A laboratory and takes into account various radioprotection procedures to prevent irradiation and contamination.
Background
An isotope of an element contains the same number of protons, but a different number of neutrons, giving it a different mass number than the element found on the periodic table. Isotopes with a large variation in nucleon number will decay into more stable nuclei, and are known as radionuclides or radioisotopes.
The field of nuclear medicine uses radioisotopes to diagnose and treat patients. The radiation and particles emitted by these radioisotopes can be used to weaken or destroy target cells, for example in the case of cancer. For diagnosis, a radioactive dose is given to a patient and its activity can be tracked to study the functionality of a target organ. The tracers used within this process are generally short-lived isotopes.
Diagnostic radiopharmaceuticals are used to examine organ functionality, blood flow, bone growth and other diagnostic procedures. Radioisotopes needed for this procedure must emit gamma radiation with a high energy and short half-life, in order for it to escape the body and decay quickly. There is currently a tren
Document 2:::
Stable nuclides are nuclides that are not radioactive and so (unlike radionuclides) do not spontaneously undergo radioactive decay. When such nuclides are referred to in relation to specific elements, they are usually termed stable isotopes.
The 80 elements with one or more stable isotopes comprise a total of 251 nuclides that have not been known to decay using current equipment (see list at the end of this article). Of these 80 elements, 26 have only one stable isotope; they are thus termed monoisotopic. The rest have more than one stable isotope. Tin has ten stable isotopes, the largest number of stable isotopes known for an element.
Definition of stability, and naturally occurring nuclides
Most naturally occurring nuclides are stable (about 251; see list at the end of this article), and about 35 more (total of 286) are known to be radioactive with sufficiently long half-lives (also known) to occur primordially. If the half-life of a nuclide is comparable to, or greater than, the Earth's age (4.5 billion years), a significant amount will have survived since the formation of the Solar System, and then is said to be primordial. It will then contribute in that way to the natural isotopic composition of a chemical element. Primordially present radioisotopes are easily detected with half-lives as short as 700 million years (e.g., 235U). This is the present limit of detection, as shorter-lived nuclides have not yet been detected undisputedly in nature except when recently produced, such as decay products or cosmic ray spallation.
Many naturally occurring radioisotopes (another 53 or so, for a total of about 339) exhibit still shorter half-lives than 700 million years, but they are made freshly, as daughter products of decay processes of primordial nuclides (for example, radium from uranium) or from ongoing energetic reactions, such as cosmogenic nuclides produced by present bombardment of Earth by cosmic rays (for example, 14C made from nitrogen).
Some isotopes th
Document 3:::
A synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. Examples include technetium-95 and promethium-146. Many of these are found in, and harvested from, spent nuclear fuel assemblies. Some must be manufactured in particle accelerators.
Production
Some synthetic radioisotopes are extracted from spent nuclear reactor fuel rods, which contain various fission products. For example, it is estimated that up to 1994, about 49,000 terabecquerels (78 metric ton) of technetium was produced in nuclear reactors, which is by far the dominant source of terrestrial technetium.
Some synthetic isotopes are produced in significant quantities by fission but are not yet being reclaimed. Other isotopes are manufactured by neutron irradiation of parent isotopes in a nuclear reactor (for example, Tc-97 can be made by neutron irradiation of Ru-96) or by bombarding parent isotopes with high energy particles from a particle accelerator.
Many isotopes are produced in cyclotrons, for example fluorine-18 and oxygen-15 which are widely used for positron emission tomography.
Uses
Most synthetic radioisotopes have a short half-life. Though a health hazard, radioactive materials have many medical and industrial uses.
Nuclear medicine
The field of nuclear medicine covers use of radioisotopes for diagnosis or treatment.
Diagnosis
Radioactive tracer compounds, radiopharmaceuticals, are used to observe the function of various organs and body systems. These compounds use a chemical tracer which is attracted to or concentrated by the activity which is being studied. That chemical tracer incorporates a short lived radioactive isotope, usually one which emits a gamma ray which is energetic enough to travel through the body and be captured outside by a gamma camera to map the concentrations. Gamma cameras and other similar detectors are highly efficient
Document 4:::
A radiogenic nuclide is a nuclide that is produced by a process of radioactive decay. It may itself be radioactive (a radionuclide) or stable (a stable nuclide).
Radiogenic nuclides (more commonly referred to as radiogenic isotopes) form some of the most important tools in geology. They are used in two principal ways:
In comparison with the quantity of the radioactive 'parent isotope' in a system, the quantity of the radiogenic 'daughter product' is used as a radiometric dating tool (e.g. uranium–lead geochronology).
In comparison with the quantity of a non-radiogenic isotope of the same element, the quantity of the radiogenic isotope is used to define its isotopic signature (e.g. 206Pb/204Pb). This technique is discussed in more detail under the heading isotope geochemistry.
Examples
Some naturally occurring isotopes are entirely radiogenic, but all those are radioactive isotopes, with half-lives too short to have occurred primordially and still exist today. Thus, they are only present as radiogenic daughters of either ongoing decay processes, or else cosmogenic (cosmic ray induced) processes that produce them in nature freshly. A few others are naturally produced by nucleogenic processes (natural nuclear reactions of other types, such as neutron absorption).
For radiogenic isotopes that decay slowly enough, or that are stable isotopes, a primordial fraction is always present, since all sufficiently long-lived and stable isotopes do in fact naturally occur primordially. An additional fraction of some of these isotopes may also occur radiogenically.
Lead is perhaps the best example of a partly radiogenic substance, as all four of its stable isotopes (204Pb, 206Pb, 207Pb, and 208Pb) are present primordially, in known and fixed ratios. However, 204Pb is only present primordially, while the other three isotopes may also occur as radiogenic decay products of uranium and thorium. Specifically, 206Pb is formed from 238U, 207Pb from 235U, and 208Pb from 232Th. In ro
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What type of isotopes have short half-lives and are given in very low doses?
A. gasses
B. stable isotopes
C. radioisotopes
D. radionuclides
Answer:
|
|
sciq-4589
|
multiple_choice
|
The ions in ionic compounds are arranged in rigid three-dimensional patterns called what?
|
[
"core lattices",
"pattern lattices",
"lattice groups",
"crystal lattices"
] |
D
|
Relavent Documents:
Document 0:::
In crystallography, a crystal system is a set of point groups (a group of geometric symmetries with at least one fixed point). A lattice system is a set of Bravais lattices. Space groups are classified into crystal systems according to their point groups, and into lattice systems according to their Bravais lattices. Crystal systems that have space groups assigned to a common lattice system are combined into a crystal family.
The seven crystal systems are triclinic, monoclinic, orthorhombic, tetragonal, trigonal, hexagonal, and cubic. Informally, two crystals are in the same crystal system if they have similar symmetries (albeit there are many exceptions).
Classifications
Crystals can be classified in three ways: lattice systems, crystal systems and crystal families. The various classifications are often confused: in particular the trigonal crystal system is often confused with the rhombohedral lattice system, and the term "crystal system" is sometimes used to mean "lattice system" or "crystal family".
Lattice system
A lattice system is a group of lattices with the same set of lattice point groups. The 14 Bravais lattices are grouped into seven lattice systems: triclinic, monoclinic, orthorhombic, tetragonal, rhombohedral, hexagonal, and cubic.
Crystal system
A crystal system is a set of point groups in which the point groups themselves and their corresponding space groups are assigned to a lattice system. Of the 32 crystallographic point groups that exist in three dimensions, most are assigned to only one lattice system, in which case both the crystal and lattice systems have the same name. However, five point groups are assigned to two lattice systems, rhombohedral and hexagonal, because both exhibit threefold rotational symmetry. These point groups are assigned to the trigonal crystal system.
Crystal family
A crystal family is determined by lattices and point groups. It is formed by combining crystal systems that have space groups assigned to a common l
Document 1:::
The rectangular lattice and rhombic lattice (or centered rectangular lattice) constitute two of the five two-dimensional Bravais lattice types. The symmetry categories of these lattices are wallpaper groups pmm and cmm respectively. The conventional translation vectors of the rectangular lattices form an angle of 90° and are of unequal lengths.
Bravais lattices
There are two rectangular Bravais lattices: primitive rectangular and centered rectangular (also rhombic).
The primitive rectangular lattice can also be described by a centered rhombic unit cell, while the centered rectangular lattice can also be described by a primitive rhombic unit cell. Note that the length in the lower row is not the same as in the upper row. For the first column above, of the second row equals of the first row, and for the second column it equals .
Crystal classes
The rectangular lattice class names, Schönflies notation, Hermann-Mauguin notation, orbifold notation, Coxeter notation, and wallpaper groups are listed in the table below.
Document 2:::
In crystallography, the diamond cubic crystal structure is a repeating pattern of 8 atoms that certain materials may adopt as they solidify. While the first known example was diamond, other elements in group 14 also adopt this structure, including α-tin, the semiconductors silicon and germanium, and silicon–germanium alloys in any proportion. There are also crystals, such as the high-temperature form of cristobalite, which have a similar structure, with one kind of atom (such as silicon in cristobalite) at the positions of carbon atoms in diamond but with another kind of atom (such as oxygen) halfway between those (see :Category:Minerals in space group 227).
Although often called the diamond lattice, this structure is not a lattice in the technical sense of this word used in mathematics.
Crystallographic structure
Diamond's cubic structure is in the Fdm space group (space group 227), which follows the face-centered cubic Bravais lattice. The lattice describes the repeat pattern; for diamond cubic crystals this lattice is "decorated" with a motif of two tetrahedrally bonded atoms in each primitive cell, separated by of the width of the unit cell in each dimension. The diamond lattice can be viewed as a pair of intersecting face-centered cubic lattices, with each separated by of the width of the unit cell in each dimension. Many compound semiconductors such as gallium arsenide, β-silicon carbide, and indium antimonide adopt the analogous zincblende structure, where each atom has nearest neighbors of an unlike element. Zincblende's space group is F3m, but many of its structural properties are quite similar to the diamond structure.
The atomic packing factor of the diamond cubic structure (the proportion of space that would be filled by spheres that are centered on the vertices of the structure and are as large as possible without overlapping) is significantly smaller (indicating a less dense structure) than the packing factors for the face-centered and body-cent
Document 3:::
In geometry, biology, mineralogy and solid state physics, a unit cell is a repeating unit formed by the vectors spanning the points of a lattice. Despite its suggestive name, the unit cell (unlike a unit vector, for example) does not necessarily have unit size, or even a particular size at all. Rather, the primitive cell is the closest analogy to a unit vector, since it has a determined size for a given lattice and is the basic building block from which larger cells are constructed.
The concept is used particularly in describing crystal structure in two and three dimensions, though it makes sense in all dimensions. A lattice can be characterized by the geometry of its unit cell, which is a section of the tiling (a parallelogram or parallelepiped) that generates the whole tiling using only translations.
There are two special cases of the unit cell: the primitive cell and the conventional cell. The primitive cell is a unit cell corresponding to a single lattice point, it is the smallest possible unit cell. In some cases, the full symmetry of a crystal structure is not obvious from the primitive cell, in which cases a conventional cell may be used. A conventional cell (which may or may not be primitive) is a unit cell with the full symmetry of the lattice and may include more than one lattice point. The conventional unit cells are parallelotopes in n dimensions.
Primitive cell
A primitive cell is a unit cell that contains exactly one lattice point. For unit cells generally, lattice points that are shared by cells are counted as of the lattice points contained in each of those cells; so for example a primitive unit cell in three dimensions which has lattice points only at its eight vertices is considered to contain of each of them. An alternative conceptualization is to consistently pick only one of the lattice points to belong to the given unit cell (so the other lattice points belong to adjacent unit cells).
The primitive translation vectors , , span a la
Document 4:::
In crystallography, a fractional coordinate system (crystal coordinate system) is a coordinate system in which basis vectors used to the describe the space are the lattice vectors of a crystal (periodic) pattern. The selection of an origin and a basis define a unit cell, a parallelotope (i.e., generalization of a parallelogram (2D) or parallelepiped (3D) in higher dimensions) defined by the lattice basis vectors where is the dimension of the space. These basis vectors are described by lattice parameters (lattice constants) consisting of the lengths of the lattice basis vectors and the angles between them .
Most cases in crystallography involve two- or three-dimensional space in which the basis vectors are commonly displayed as with their lengths and angles denoted by and respectively.
Crystal Structure
A crystal structure is defined as the spatial distribution of the atoms within a crystal, usually modeled by the idea of an infinite crystal pattern. An infinite crystal pattern refers to the infinite 3D periodic array which corresponds to a crystal, in which the lengths of the periodicities of the array may not be made arbitrarily small. The geometrical shift which takes a crystal structure coincident with itself is termed a symmetry translation (translation) of the crystal structure. The vector which is related to this shift is called a translation vector . Since a crystal pattern is periodic, all integer linear combinations of translation vectors are also themselves translation vectors,
Lattice
The vector lattice (lattice) is defined as the infinite set consisting of all of the translation vectors of a crystal pattern. Each of the vectors in the vector lattice are called lattice vectors. From the vector lattice it is possible to construct a point lattice. This is done by selecting an origin with position vector . The endpoints of each of the vectors make up the point lattice of and . Each point in a point lattice has periodicity i.e., each point
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
The ions in ionic compounds are arranged in rigid three-dimensional patterns called what?
A. core lattices
B. pattern lattices
C. lattice groups
D. crystal lattices
Answer:
|
|
sciq-1084
|
multiple_choice
|
What type of pollution is generated by power plants and factories that can directly raise the temperature of water?
|
[
"atmospheric pollution",
"Space Pollution",
"variable pollution",
"thermal pollution"
] |
D
|
Relavent Documents:
Document 0:::
Bioremediation broadly refers to any process wherein a biological system (typically bacteria, microalgae, fungi in mycoremediation, and plants in phytoremediation), living or dead, is employed for removing environmental pollutants from air, water, soil, flue gasses, industrial effluents etc., in natural or artificial settings. The natural ability of organisms to adsorb, accumulate, and degrade common and emerging pollutants has attracted the use of biological resources in treatment of contaminated environment. In comparison to conventional physicochemical treatment methods bioremediation may offer considerable advantages as it aims to be sustainable, eco-friendly, cheap, and scalable.
Most bioremediation is inadvertent, involving native organisms. Research on bioremediation is heavily focused on stimulating the process by inoculation of a polluted site with organisms or supplying nutrients to promote the growth. In principle, bioremediation could be used to reduce the impact of byproducts created from anthropogenic activities, such as industrialization and agricultural processes. Bioremediation could prove less expensive and more sustainable than other remediation alternatives.
UNICEF, power producers, bulk water suppliers and local governments are early adopters of low cost bioremediation, such as aerobic bacteria tablets which are simply dropped into water.
While organic pollutants are susceptible to biodegradation, heavy metals are not degraded, but rather oxidized or reduced. Typical bioremediations involves oxidations. Oxidations enhance the water-solubility of organic compounds and their susceptibility to further degradation by further oxidation and hydrolysis. Ultimately biodegradation converts hydrocarbons to carbon dioxide and water. For heavy metals, bioremediation offers few solutions. Metal-containing pollutant can be removed or reduced with varying bioremediation techniques. The main challenge to bioremediations is rate: the processes are slow.
B
Document 1:::
The worst-case analysis regulation was promulgated in 1979 by the US Council on Environmental Quality (CEQ). The regulation is one of many implementing the National Environmental Policy Act of 1969 and it sets out the formal procedure a US government agency must follow when confronted with gaps in relevant information or scientific uncertainty about significant adverse effects on the environment from a major federal action.
Synopsis
The regulation requires an agency to make known when it is confronted with gaps in relevant information or scientific uncertainty. The agency then must determine if the missing information is essential to a reasoned choice among the alternatives. When the missing information is material to the decision an agency ordinarily must obtain the information and include it in an environmental impact statement (EIS). If the means for obtaining the missing information are beyond the state of the art or alternatively if the costs of obtaining it are exorbitant the agency must then prepare a worst-case analysis. In this analysis the agency must weigh the need for the action against the risks and in the face of uncertainty. The agency also is to indicate the probability or improbability of the worst case's occurrence.
Document 2:::
At the global scale sustainability and environmental management involves managing the oceans, freshwater systems, land and atmosphere, according to sustainability principles.
Land use change is fundamental to the operations of the biosphere because alterations in the relative proportions of land dedicated to urbanisation, agriculture, forest, woodland, grassland and pasture have a marked effect on the global water, carbon and nitrogen biogeochemical cycles. Management of the Earth's atmosphere involves assessment of all aspects of the carbon cycle to identify opportunities to address human-induced climate change and this has become a major focus of scientific research because of the potential catastrophic effects on biodiversity and human communities. Ocean circulation patterns have a strong influence on climate and weather and, in turn, the food supply of both humans and other organisms.
Atmosphere
In March 2009, at a meeting of the Copenhagen Climate Council, 2,500 climate experts from 80 countries issued a keynote statement that there is now "no excuse" for failing to act on global warming and without strong carbon reduction targets "abrupt or irreversible" shifts in climate may occur that "will be very difficult for contemporary societies to cope with". Management of the global atmosphere now involves assessment of all aspects of the carbon cycle to identify opportunities to address human-induced climate change and this has become a major focus of scientific research because of the potential catastrophic effects on biodiversity and human communities.
Other human impacts on the atmosphere include the air pollution in cities, the pollutants including toxic chemicals like nitrogen oxides, sulphur oxides, volatile organic compounds and airborne particulate matter that produce photochemical smog and acid rain, and the chlorofluorocarbons that degrade the ozone layer. Anthropogenic particulates such as sulfate aerosols in the atmosphere reduce the direct irradianc
Document 3:::
Nutrient cycling in the Columbia River Basin involves the transport of nutrients through the system, as well as transformations from among dissolved, solid, and gaseous phases, depending on the element. The elements that constitute important nutrient cycles include macronutrients such as nitrogen (as ammonium, nitrite, and nitrate), silicate, phosphorus, and micronutrients, which are found in trace amounts, such as iron. Their cycling within a system is controlled by many biological, chemical, and physical processes.
The Columbia River Basin is the largest freshwater system of the Pacific Northwest, and due to its complexity, size, and modification by humans, nutrient cycling within the system is affected by many different components. Both natural and anthropogenic processes are involved in the cycling of nutrients. Natural processes in the system include estuarine mixing of fresh and ocean waters, and climate variability patterns such as the Pacific Decadal Oscillation and the El Nino Southern Oscillation (both climatic cycles that affect the amount of regional snowpack and river discharge). Natural sources of nutrients in the Columbia River include weathering, leaf litter, salmon carcasses, runoff from its tributaries, and ocean estuary exchange. Major anthropogenic impacts to nutrients in the basin are due to fertilizers from agriculture, sewage systems, logging, and the construction of dams.
Nutrients dynamics vary in the river basin from the headwaters to the main river and dams, to finally reaching the Columbia River estuary and ocean. Upstream in the headwaters, salmon runs are the main source of nutrients. Dams along the river impact nutrient cycling by increasing residence time of nutrients, and reducing the transport of silicate to the estuary, which directly impacts diatoms, a type of phytoplankton. The dams are also a barrier to salmon migration, and can increase the amount of methane locally produced. The Columbia River estuary exports high rates of n
Document 4:::
The Certification for Sustainable Transportation is a national program housed at the University of Vermont Extension that seeks to promote the practice of using energy efficient modes of transportation. The CST work centers on its eRating vehicle certification program, which is an eco-label for passenger transportation vehicles. The eRating uses a sustainability index which includes factors such as green house gas emissions per passenger mile, emission levels of criteria pollutants, and in certain circumstances factors such as training for drivers and use of endorsed carbon offsets. Once a certain threshold is met, vehicles may qualify for e1, e2, e3, or e4 levels in the certification program.
Other key components of the CST's work are online and in person training programs. The CST offers training programs geared to help drivers and organizations eliminate all unnecessary idling and on eco-driving. These training programs are focused on helping reduce environmental impacts, save fuel, and save money.
The CST is now actively working with companies in 48 states and three Canadian provinces to prevent unnecessary emissions, reduce environmental impact, and decrease consumption of fossil fuels.
This program is not to be confused with the "E-Mark" vehicle equipment safety certification promulgated by the European Union since 2002 under EU Directive 72/245/EEC and amendments to the requirements of Directive 95/54/EC.
History
In 2007, the University of Vermont began the Green Coach Certification research project, which sought to investigate what efficiency standards would be best applied to motor coaches to promote greater energy sustainability. Research was conducted on actual motor coach companies. It also researched whether a certification program could help reduce environmental impacts from the motor coach industry by educating operators and executives about the benefits, both financial and environmental, of adopting fuel saving strategies and switching to alterna
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What type of pollution is generated by power plants and factories that can directly raise the temperature of water?
A. atmospheric pollution
B. Space Pollution
C. variable pollution
D. thermal pollution
Answer:
|
|
sciq-5290
|
multiple_choice
|
What were the first living things to evolve on earth?
|
[
"eukaryotes",
"carbon",
"DNA",
"prokaryotes"
] |
D
|
Relavent Documents:
Document 0:::
The history of life on Earth traces the processes by which living and fossil organisms evolved, from the earliest emergence of life to present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. Although there is some evidence of life as early as 4.1 to 4.28 Ga, it remains controversial due to the possible non-biological formation of the purported fossils.
The similarities among all known present-day species indicate that they have diverged through the process of evolution from a common ancestor. Only a very small percentage of species have been identified: one estimate claims that Earth may have 1 trillion species. However, only 1.75–1.8 million have been named and 1.8 million documented in a central database. These currently living species represent less than one percent of all species that have ever lived on Earth.
The earliest evidence of life comes from biogenic carbon signatures and stromatolite fossils discovered in 3.7 billion-year-old metasedimentary rocks from western Greenland. In 2015, possible "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia. In March 2017, putative evidence of possibly the oldest forms of life on Earth was reported in the form of fossilized microorganisms discovered in hydrothermal vent precipitates in the Nuvvuagittuq Belt of Quebec, Canada, that may have lived as early as 4.28 billion years ago, not long after the oceans formed 4.4 billion years ago, and not long after the formation of the Earth 4.54 billion years ago.
Microbial mats of coexisting bacteria and archaea were the dominant form of life in the early Archean eon and many of the major steps in early evolution are thought to have taken place in this environment. The evolution of photosynthesis by cyanobacteria, around 3.5 Ga, eventually led to a buildup of its waste product, oxygen, in the ocean and then the atmosphere after depleting all available
Document 1:::
Scientists trying to reconstruct evolutionary history have been challenged by the fact that genes can sometimes transfer between distant branches on the tree of life. This movement of genes can occur through horizontal gene transfer (HGT), scrambling the information on which biologists relied to reconstruct the phylogeny of organisms. Conversely, HGT can also help scientists to reconstruct and date the tree of life. Indeed, a gene transfer can be used as a phylogenetic marker, or as the proof of contemporaneity of the donor and recipient organisms, and as a trace of extinct biodiversity.
HGT happens very infrequently – at the individual organism level, it is highly improbable for any such event to take place. However, on the grander scale of evolutionary history, these events occur with some regularity. On one hand, this forces biologists to abandon the use of individual genes as good markers for the history of life. On the other hand, this provides an almost unexploited large source of information about the past.
Three domains of life
The three main early branches of the tree of life have been intensively studied by microbiologists because the first organisms were microorganisms. Microbiologists (led by Carl Woese) have introduced the term domain for the three main branches of this tree, where domain is a phylogenetic term similar in meaning to biological kingdom. To reconstruct this tree of life, the gene sequence encoding the small subunit of ribosomal RNA (SSU rRNA, 16s rRNA) has proven useful, and the tree (as shown in the picture) relies heavily on information from this single gene.
These three domains of life represent the main evolutionary lineages of early cellular life and currently include Bacteria, Archaea (single-celled organisms superficially similar to bacteria), and Eukarya. Eukarya includes only organisms having a well-defined nucleus, such as fungi, protists, and all organisms in the plant and animals kingdoms (see figure).
The gene most com
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Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary information encoded in genes, which can be transmitted to future generations. Another major theme is evolution, which explains the unity and diversity of life. Energy processing is also important to life as it allows organisms to move, grow, and reproduce. Finally, all organisms are able to regulate their own internal environments.
Biologists are able to study life at multiple levels of organization, from the molecular biology of a cell to the anatomy and physiology of plants and animals, and evolution of populations. Hence, there are multiple subdisciplines within biology, each defined by the nature of their research questions and the tools that they use. Like other scientists, biologists use the scientific method to make observations, pose questions, generate hypotheses, perform experiments, and form conclusions about the world around them.
Life on Earth, which emerged more than 3.7 billion years ago, is immensely diverse. Biologists have sought to study and classify the various forms of life, from prokaryotic organisms such as archaea and bacteria to eukaryotic organisms such as protists, fungi, plants, and animals. These various organisms contribute to the biodiversity of an ecosystem, where they play specialized roles in the cycling of nutrients and energy through their biophysical environment.
History
The earliest of roots of science, which included medicine, can be traced to ancient Egypt and Mesopotamia in around 3000 to 1200 BCE. Their contributions shaped ancient Greek natural philosophy. Ancient Greek philosophers such as Aristotle (384–322 BCE) contributed extensively to the development of biological knowledge. He explored biological causation and the diversity of life. His successor, Theophrastus, began the scienti
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The history of life on Earth seems to show a clear trend; for example, it seems intuitive that there is a trend towards increasing complexity in living organisms. More recently evolved organisms, such as mammals, appear to be much more complex than organisms, such as bacteria, which have existed for a much longer period of time. However, there are theoretical and empirical problems with this claim. From a theoretical perspective, it appears that there is no reason to expect evolution to result in any largest-scale trends, although small-scale trends, limited in time and space, are expected (Gould, 1997). From an empirical perspective, it is difficult to measure complexity and, when it has been measured, the evidence does not support a largest-scale trend (McShea, 1996).
History
Many of the founding figures of evolution supported the idea of Evolutionary progress which has fallen from favour, but the work of Francisco J. Ayala and Michael Ruse suggests is still influential.
Hypothetical largest-scale trends
McShea (1998) discusses eight features of organisms that might indicate largest-scale trends in evolution: entropy, energy intensiveness, evolutionary versatility, developmental depth, structural depth, adaptedness, size, complexity. He calls these "live hypotheses", meaning that trends in these features are currently being considered by evolutionary biologists. McShea observes that the most popular hypothesis, among scientists, is that there is a largest-scale trend towards increasing complexity.
Evolutionary theorists agree that there are local trends in evolution, such as increasing brain size in hominids, but these directional changes do not persist indefinitely, and trends in opposite directions also occur (Gould, 1997). Evolution causes organisms to adapt to their local environment; when the environment changes, the direction of the trend may change. The question of whether there is evolutionary progress is better formulated as the question of whether
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Eukaryogenesis, the process which created the eukaryotic cell and lineage, is a milestone in the evolution of life, since eukaryotes include all complex cells and almost all multicellular organisms. The process is widely agreed to have involved symbiogenesis, in which archaea and bacteria came together to create the first eukaryotic common ancestor (FECA). This cell had a new level of complexity and capability, with a nucleus, at least one centriole and cilium, facultatively aerobic mitochondria, sex (meiosis and syngamy), a dormant cyst with a cell wall of chitin and/or cellulose and peroxisomes. It evolved into a population of single-celled organisms that included the last eukaryotic common ancestor (LECA), gaining capabilities along the way, though the sequence of the steps involved has been disputed, and may not have started with symbiogenesis. In turn, the LECA gave rise to the eukaryotes' crown group, containing the ancestors of animals, fungi, plants, and a diverse range of single-celled organisms.
Context
Life arose on Earth once it had cooled enough for oceans to form. The last universal common ancestor (LUCA) was an organism which had ribosomes and the genetic code; it lived some 4 billion years ago. It gave rise to two main branches of prokaryotic life, the bacteria and the archaea. From among these small-celled, rapidly-dividing ancestors arose the Eukaryotes, with much larger cells, nuclei, and distinctive biochemistry. The eukaryotes form a domain that contains all complex cells and most types of multicellular organism, including the animals, plants, and fungi.
Symbiogenesis
According to the theory of symbiogenesis (also known as the endosymbiotic theory) championed by Lynn Margulis, a member of the archaea gained a bacterial cell as a component. The archaeal cell was a member of the Asgard group. The bacterium was one of the Alphaproteobacteria, which had the ability to use oxygen in its respiration. This enabled it – and the archaeal cells that
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What were the first living things to evolve on earth?
A. eukaryotes
B. carbon
C. DNA
D. prokaryotes
Answer:
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|
ai2_arc-819
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multiple_choice
|
The marsh willow herb is a plant native to the northeastern United States. It grows best in damp habitats. Which of the following environmental changes would most likely cause a decrease in the marsh willow herb population in an area?
|
[
"a rainstorm lasting several weeks",
"a drought lasting twelve months",
"unusually low temperatures during the month of July",
"unusually high temperatures during the month of January"
] |
B
|
Relavent Documents:
Document 0:::
The Park Grass Experiment is a biological study originally set up to test the effect of fertilizers and manures on hay yields. The scientific experiment is located at the Rothamsted Research in the English county of Hertfordshire, and is notable as one of the longest-running experiments of modern science, as it was initiated in 1856 and has been continually monitored ever since.
The experiment was originally designed to answer agricultural questions but has since proved an invaluable resource for studying natural selection and biodiversity. The treatments under study were found to be affecting the botanical make-up of the plots and the ecology of the field and it has been studied ever since. In spring, the field is a colourful tapestry of flowers and grasses, some plots still having the wide range of plants that most meadows probably contained hundreds of years ago.
Over its history, Park Grass has:
demonstrated that conventional field trials probably underestimate threats to plant biodiversity from long term changes, such as soil acidification,
shown how plant species richness, biomass and pH are related,
demonstrated that competition between plants can make the effects of climatic variation on communities more extreme,
provided one of the first demonstrations of local evolutionary change under different selection pressures and
endowed us with an archive of soil and hay samples that have been used to track the history of atmospheric pollution, including nuclear fallout.
Bibliography
Rothamsted Research: Classical Experiments
Biodiversity
Ecological experiments
Grasslands
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A wet meadow is a type of wetland with soils that are saturated for part or all of the growing season which prevents the growth of trees and brush. Debate exists whether a wet meadow is a type of marsh or a completely separate type of wetland. Wet prairies and wet savannas are hydrologically similar.
Hydrology and ecology
Wet meadows may occur because of restricted drainage or the receipt of large amounts of water from rain or melted snow. They may also occur in riparian zones and around the shores of large lakes.
Unlike a marsh or swamp, a wet meadow does not have standing water present except for brief to moderate periods during the growing season. Instead, the ground in a wet meadow fluctuates between brief periods of inundation and longer periods of saturation. Wet meadows often have large numbers of wetland plant species, which frequently survive as buried seeds during dry periods, and then regenerate after flooding. Wet meadows therefore do not usually support aquatic life such as fish. They typically have a high diversity of plant species, and may attract large numbers of birds, small mammals and insects including butterflies.
Vegetation in a wet meadow usually includes a wide variety of herbaceous species including sedges, rushes, grasses and a wide diversity of other plant species. A few of many possible examples include species of Rhexia, Parnassia, Lobelia, many species of wild orchids (e.g. Calopogon and Spiranthes), and carnivorous plants such as Sarracenia and Drosera. Woody plants, if present, account for a minority of the total area cover. High water levels are one of the important factors that prevent invasion by woody plants; in other cases, fire is important. In areas with low frequencies of fire, or reduced water level fluctuations, or higher fertility, plant diversity will decline.
Conservation
Wet meadows were once common in wetland types around the world. They remain an important community type in wet savannas and flatwoods. The also su
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Specific leaf area (SLA) is the ratio of leaf area to leaf dry mass. The inverse of SLA is Leaf Mass per Area (LMA).
Rationale
Specific leaf area is a ratio indicating how much leaf area a plant builds with a given amount of leaf biomass:
where A is the area of a given leaf or all leaves of a plant, and ML is the dry mass of those leaves. Typical units are m2kg−1 or mm2mg−1.
Leaf mass per area (LMA) is its inverse and can mathematically be decomposed in two component variables, leaf thickness (LTh) and leaf density (LD):
Typical units are g.m−2 for LMA, µm for LTh and g.ml−1 for LD.
Both SLA and LMA are frequently used in plant ecology and biology. SLA is one of the components in plant growth analysis, and mathematically scales positively and linearly with the relative growth rate of a plant. LMA mathematically scales positively with the investments plants make per unit leaf area (amount of protein and cell wall; cell number per area) and with leaf longevity. Since linear, positive relationships are more easily analysed than inverse negative relationships, researchers often use either variable, depending on the type of questions asked.
Normal Ranges
Normal ranges of SLA and LMA are species-dependent and influenced by growth environment. Table 1 gives normal ranges (~10th and ~90th percentiles) for species growing in the field, for well-illuminated leaves. Aquatic plants generally have very low LMA values, with particularly low numbers reported for species such as Myriophyllum farwelli (2.8 g.m−2) and Potamogeton perfoliatus (3.9 g. m−2). Evergreen shrubs and Gymnosperm trees as well as succulents have particularly high LMA values, with highest values reported for Aloe saponaria (2010 g.m−2) and Agave deserti (2900 g.m−2).
Application
Specific leaf area can be used to estimate the reproductive strategy of a particular plant based upon light and moisture (humidity) levels, among other factors. Specific leaf area is one of the most widely accepted key leaf chara
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Conservation grazing or targeted grazing is the use of semi-feral or domesticated grazing livestock to maintain and increase the biodiversity of natural or semi-natural grasslands, heathlands, wood pasture, wetlands and many other habitats. Conservation grazing is generally less intensive than practices such as prescribed burning, but still needs to be managed to ensure that overgrazing does not occur. The practice has proven to be beneficial in moderation in restoring and maintaining grassland and heathland ecosystems. The optimal level of grazing will depend on the goal of conservation, and different levels of grazing, alongside other conservation practices, can be used to induce the desired results.
History
For historic grasslands, grazing animals, herbivores, were a crucial part of the ecosystem. When grazers are removed, historically grazed lands may show a decline in both the density and the diversity of the vegetation. The history of the land may help ecologists and conservationists determine the best approach to a conservation project.
Historic threats to grasslands began with land conversion to crop fields. This shifted to improper land management techniques and more recently to the spread of woody plants due to a lack of management and to climate change.
Conservation grazing in practice
Intensive grazing maintains an area as a habitat dominated by grasses and small shrubs, largely preventing ecological succession to forest.
Extensive grazing also treats habitats dominated by grasses and small shrubs but does not prevent succession to forest, it only slows it down.
Conservation grazing is usually done with extensive grazing because of the ecological disadvantages of intensive grazing.
Conservation grazing needs to be monitored closely. Overgrazing may cause erosion, habitat destruction, soil compaction, or reduced biodiversity (species richness).
Rambo and Faeth found that the use of vertebrates for grazing of an area increased the species richness o
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In ecology, a mesic habitat is a type of habitat with a well-balanced supply of moisture throughout the growing season, e.g., a mesic forest, a temperate hardwood forest, or dry-mesic prairie. Mesic is one of a triad of terms used to label a habitat or area that has a moderate or well-balanced supply of water within.
The presence of water to allow for a habitat to be labeled as mesic can arise from a number of outside factors. A handful of the processes that allow for this moderate moisture content to remain constant during crucial growing periods include streams and their offshoots, wet meadows, springs, seeps, irrigated fields, and high-elevation habitats. These factors effectively provide drought insurance during the growing season as climate factors such as increasing temperatures, lack of rain, and especially urbanization in today's current light.
Other habitat types, such as mesic hammocks, occupy the middle ground between bottomlands and sandhills or clay hills. These habitats can often be governed by oaks, hickories, and magnolias. However, there are some habitats that exhibit adaptations to fire. Natural Pinelands can persist in conjunction with mesic (moderately drained) or hydric but can also include mesic clay.
Healthy mesic habitats can store large amounts of water given the typical rich loamy soil composition and streams, springs, etc. This allows the entire habitat to essentially function like a sponge storing water in such a way that it can be deposited to neighboring habitats as needed. This supply helps to capture, store, and slowly release water. This supply aids in nutrient facilitation, bolstering community interactions.
Mesic habitats are common in dryer regions of the western United States, such as the Great Basin, Great Plains, and the Rocky Mountains. This allows for these habitats to become good water sources for neighboring dry climates and desert habitats. Healthy mesic habitats can provide extensive benefits to surrounding communi
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
The marsh willow herb is a plant native to the northeastern United States. It grows best in damp habitats. Which of the following environmental changes would most likely cause a decrease in the marsh willow herb population in an area?
A. a rainstorm lasting several weeks
B. a drought lasting twelve months
C. unusually low temperatures during the month of July
D. unusually high temperatures during the month of January
Answer:
|
|
sciq-2179
|
multiple_choice
|
Without dinoflagellate symbionts, corals lose algal pigments in a process called coral bleaching and eventually die, while corals in turn provide protection, making this what type of relationship?.
|
[
"semantic",
"symbiotic",
"idealistic",
"parasitic"
] |
B
|
Relavent Documents:
Document 0:::
Microbial symbiosis in marine animals was not discovered until 1981. In the time following, symbiotic relationships between marine invertebrates and chemoautotrophic bacteria have been found in a variety of ecosystems, ranging from shallow coastal waters to deep-sea hydrothermal vents. Symbiosis is a way for marine organisms to find creative ways to survive in a very dynamic environment. They are different in relation to how dependent the organisms are on each other or how they are associated. It is also considered a selective force behind evolution in some scientific aspects. The symbiotic relationships of organisms has the ability to change behavior, morphology and metabolic pathways. With increased recognition and research, new terminology also arises, such as holobiont, which the relationship between a host and its symbionts as one grouping. Many scientists will look at the hologenome, which is the combined genetic information of the host and its symbionts. These terms are more commonly used to describe microbial symbionts.
The type of marine animal vary greatly, for example, sponges, sea squirts, corals, worms, and algae all host a variety of unique symbionts. Each symbiotic relationship displays a unique ecological niche, which in turn can lead to entirely new species of host species and symbiont.
It is particularly interesting that it took so long to discover the marine microbial symbiosis because nearly every surface submerged in the oceans becomes covered with biofilm, including a large number of living organisms. Many marine organisms display symbiotic relationships with microbes. Epibiotic bacteria have been found to live on crustacean larvae and protect them from fungal infections. Other microbes in deep-sea vents have been found to prevent the settlement of barnacles and tunicate larvae.
Mechanisms of symbiosis
Various mechanisms are utilized in order to facilitate symbiotic relationships and to help these associates evolve alongside one anoth
Document 1:::
Mutualism describes the ecological interaction between two or more species where each species has a net benefit. Mutualism is a common type of ecological interaction. Prominent examples include most vascular plants engaged in mutualistic interactions with mycorrhizae, flowering plants being pollinated by animals, vascular plants being dispersed by animals, and corals with zooxanthellae, among many others. Mutualism can be contrasted with interspecific competition, in which each species experiences reduced fitness, and exploitation, or parasitism, in which one species benefits at the expense of the other.
The term mutualism was introduced by Pierre-Joseph van Beneden in his 1876 book Animal Parasites and Messmates to mean "mutual aid among species".
Mutualism is often conflated with two other types of ecological phenomena: cooperation and symbiosis. Cooperation most commonly refers to increases in fitness through within-species (intraspecific) interactions, although it has been used (especially in the past) to refer to mutualistic interactions, and it is sometimes used to refer to mutualistic interactions that are not obligate. Symbiosis involves two species living in close physical contact over a long period of their existence and may be mutualistic, parasitic, or commensal, so symbiotic relationships are not always mutualistic, and mutualistic interactions are not always symbiotic. Despite a different definition between mutualistic interactions and symbiosis, mutualistic and symbiosis have been largely used interchangeably in the past, and confusion on their use has persisted.
Mutualism plays a key part in ecology and evolution. For example, mutualistic interactions are vital for terrestrial ecosystem function as about 80% of land plants species rely on mycorrhizal relationships with fungi to provide them with inorganic compounds and trace elements. As another example, the estimate of tropical rainforest plants with seed dispersal mutualisms with animals ranges
Document 2:::
Bioclaustration is kind of interaction when one organism (usually soft bodied) is embedded in a living substrate (i.e. skeleton of another organism); it means “biologically walled -up”. In case of symbiosis the walling-up is not complete and both organisms stay alive (Palmer and Wilson, 1988).
Document 3:::
Coral reef restoration strategies use natural and anthropogenic processes to restore damaged coral reefs. Reefs suffer damage from a number of natural and man-made causes, and efforts are being made to rectify the damage and restore the reefs. This involves the fragmentation of mature corals, the placing of the living fragments on lines or frames, the nurturing of the fragments as they recover and grow, and the transplantation of the pieces into their final positions on the reef when they are large enough.
Background
Coral reefs are important buffers between the land and water and help to reduce storm damage and coastal erosion. They provide employment, recreational opportunities and they are a major source of food for coastal communities. It is estimated that $375 billion dollars come from ecosystem services provided by coral reefs each year.
The most prevalent coral in tropical reefs are the stony corals Scleractinia that build hard skeletons of calcium carbonate which provide protection and structure to the reef. Coral polyps have a mutualistic relationship with single-celled algae referred to as zooxanthellae. These algae live in the tissue of coral polyps and provide energy to the coral through photosynthesis. In turn, the coral provides shelter and nutrients to the zooxanthellae.
Half the world's coral since 1970 have disappeared, and all reefs being threatened with extinction by 2050. In order to ensure the existence of coral reefs in the future, new methods for restoring their ecosystems are being investigated. Fragmentation is the most common strategy for restoring reefs; often used to establish artificial reefs like coral trees, line nurseries, and fixed structures.
Threats to coral reefs
Some anthropogenic activities, such as coral mining, bottom trawling, canal digging, and blast fishing, cause physical disruption to coral reefs by damaging the corals' hard calcium carbonate skeletal structure.
Another major threat to coral reefs comes from chemica
Document 4:::
Photosymbiosis is a type of symbiosis where one of the organisms is capable of photosynthesis.
Examples
Examples of photosymbiotic relationships include those in lichens, plankton, and many marine organisms including coral, giant clams, and jellyfish.
Significance
Photosymbiosis is important in the development, maintenance, and evolution of terrestrial and aquatic ecosystems, for example through supporting soil formation, soil stabilization, and coral reef growth and maintenance.
Photosymbiotic relationships where microalgae live within a heterotrophic host organism, is believed to have led to eukaryotes acquiring photosynthesis and the evolution of plants.
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Without dinoflagellate symbionts, corals lose algal pigments in a process called coral bleaching and eventually die, while corals in turn provide protection, making this what type of relationship?.
A. semantic
B. symbiotic
C. idealistic
D. parasitic
Answer:
|
|
sciq-7369
|
multiple_choice
|
What sciences are the study of living organisms?
|
[
"life sciences",
"earth sciences",
"social sciences",
"physical sciences"
] |
A
|
Relavent Documents:
Document 0:::
This list of life sciences comprises the branches of science that involve the scientific study of life – such as microorganisms, plants, and animals including human beings. This science is one of the two major branches of natural science, the other being physical science, which is concerned with non-living matter. Biology is the overall natural science that studies life, with the other life sciences as its sub-disciplines.
Some life sciences focus on a specific type of organism. For example, zoology is the study of animals, while botany is the study of plants. Other life sciences focus on aspects common to all or many life forms, such as anatomy and genetics. Some focus on the micro-scale (e.g. molecular biology, biochemistry) other on larger scales (e.g. cytology, immunology, ethology, pharmacy, ecology). Another major branch of life sciences involves understanding the mindneuroscience. Life sciences discoveries are helpful in improving the quality and standard of life and have applications in health, agriculture, medicine, and the pharmaceutical and food science industries. For example, it has provided information on certain diseases which has overall aided in the understanding of human health.
Basic life science branches
Biology – scientific study of life
Anatomy – study of form and function, in plants, animals, and other organisms, or specifically in humans
Astrobiology – the study of the formation and presence of life in the universe
Bacteriology – study of bacteria
Biotechnology – study of combination of both the living organism and technology
Biochemistry – study of the chemical reactions required for life to exist and function, usually a focus on the cellular level
Bioinformatics – developing of methods or software tools for storing, retrieving, organizing and analyzing biological data to generate useful biological knowledge
Biolinguistics – the study of the biology and evolution of language.
Biological anthropology – the study of humans, non-hum
Document 1:::
Several universities have designed interdisciplinary courses with a focus on human biology at the undergraduate level. There is a wide variation in emphasis ranging from business, social studies, public policy, healthcare and pharmaceutical research.
Americas
Human Biology major at Stanford University, Palo Alto (since 1970)
Stanford's Human Biology Program is an undergraduate major; it integrates the natural and social sciences in the study of human beings. It is interdisciplinary and policy-oriented and was founded in 1970 by a group of Stanford faculty (Professors Dornbusch, Ehrlich, Hamburg, Hastorf, Kennedy, Kretchmer, Lederberg, and Pittendrigh). It is a very popular major and alumni have gone to post-graduate education, medical school, law, business and government.
Human and Social Biology (Caribbean)
Human and Social Biology is a Level 4 & 5 subject in the secondary and post-secondary schools in the Caribbean and is optional for the Caribbean Secondary Education Certification (CSEC) which is equivalent to Ordinary Level (O-Level) under the British school system. The syllabus centers on structure and functioning (anatomy, physiology, biochemistry) of human body and the relevance to human health with Caribbean-specific experience. The syllabus is organized under five main sections: Living organisms and the environment, life processes, heredity and variation, disease and its impact on humans, the impact of human activities on the environment.
Human Biology Program at University of Toronto
The University of Toronto offers an undergraduate program in Human Biology that is jointly offered by the Faculty of Arts & Science and the Faculty of Medicine. The program offers several major and specialist options in: human biology, neuroscience, health & disease, global health, and fundamental genetics and its applications.
Asia
BSc (Honours) Human Biology at All India Institute of Medical Sciences, New Delhi (1980–2002)
BSc (honours) Human Biology at AIIMS (New
Document 2:::
Animal science is described as "studying the biology of animals that are under the control of humankind". It can also be described as the production and management of farm animals. Historically, the degree was called animal husbandry and the animals studied were livestock species, like cattle, sheep, pigs, poultry, and horses. Today, courses available look at a broader area, including companion animals, like dogs and cats, and many exotic species. Degrees in Animal Science are offered at a number of colleges and universities. Animal science degrees are often offered at land-grant universities, which will often have on-campus farms to give students hands-on experience with livestock animals.
Education
Professional education in animal science prepares students for careers in areas such as animal breeding, food and fiber production, nutrition, animal agribusiness, animal behavior, and welfare. Courses in a typical Animal Science program may include genetics, microbiology, animal behavior, nutrition, physiology, and reproduction. Courses in support areas, such as genetics, soils, agricultural economics and marketing, legal aspects, and the environment also are offered.
Bachelor degree
At many universities, a Bachelor of Science (BS) degree in Animal Science allows emphasis in certain areas. Typical areas are species-specific or career-specific. Species-specific areas of emphasis prepare students for a career in dairy management, beef management, swine management, sheep or small ruminant management, poultry production, or the horse industry. Other career-specific areas of study include pre-veterinary medicine studies, livestock business and marketing, animal welfare and behavior, animal nutrition science, animal reproduction science, or genetics. Youth programs are also an important part of animal science programs.
Pre-veterinary emphasis
Many schools that offer a degree option in Animal Science also offer a pre-veterinary emphasis such as Iowa State University, th
Document 3:::
The mathematical sciences are a group of areas of study that includes, in addition to mathematics, those academic disciplines that are primarily mathematical in nature but may not be universally considered subfields of mathematics proper.
Statistics, for example, is mathematical in its methods but grew out of bureaucratic and scientific observations, which merged with inverse probability and then grew through applications in some areas of physics, biometrics, and the social sciences to become its own separate, though closely allied, field. Theoretical astronomy, theoretical physics, theoretical and applied mechanics, continuum mechanics, mathematical chemistry, actuarial science, computer science, computational science, data science, operations research, quantitative biology, control theory, econometrics, geophysics and mathematical geosciences are likewise other fields often considered part of the mathematical sciences.
Some institutions offer degrees in mathematical sciences (e.g. the United States Military Academy, Stanford University, and University of Khartoum) or applied mathematical sciences (for example, the University of Rhode Island).
See also
Document 4:::
The Bachelor of Science in Aquatic Resources and Technology (B.Sc. in AQT) (or Bachelor of Aquatic Resource) is an undergraduate degree that prepares students to pursue careers in the public, private, or non-profit sector in areas such as marine science, fisheries science, aquaculture, aquatic resource technology, food science, management, biotechnology and hydrography. Post-baccalaureate training is available in aquatic resource management and related areas.
The Department of Animal Science and Export Agriculture, at the Uva Wellassa University of Badulla, Sri Lanka, has the largest enrollment of undergraduate majors in Aquatic Resources and Technology, with about 200 students as of 2014.
The Council on Education for Aquatic Resources and Technology includes undergraduate AQT degrees in the accreditation review of Aquatic Resources and Technology programs and schools.
See also
Marine Science
Ministry of Fisheries and Aquatic Resources Development
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What sciences are the study of living organisms?
A. life sciences
B. earth sciences
C. social sciences
D. physical sciences
Answer:
|
|
sciq-3351
|
multiple_choice
|
What branch of science is based on the modern atomic theory, which states that all matter is composed of atoms?
|
[
"chemistry",
"psychology",
"biology",
"physics"
] |
A
|
Relavent Documents:
Document 0:::
A pre-STEM program is a course of study at any two-year college that prepares a student to transfer to a four-year school to earn a bachelor's degree in a STEM field.
Overview
The concept of a pre-STEM program is being developed to address America's need for more college-trained professionals in science, technology, engineering, and mathematics (STEM). It is an innovation meant to fill a gap at community colleges that do not have 'major' degree paths that students identify with on their way to earning an Associates degree. Students must complete a considerable amount of STEM coursework before transferring from a two-year school to a four-year school and earn a baccalaureate degree in a STEM field. Schools with a pre-STEM program are able to identify those students and support them with STEM-specific academic and career advising, increasing the student's chances of going on to earn a STEM baccalaureate degree in a timely fashion.
With over 50% of America's college-bound students starting their college career at public or private two-year school, and with a very small proportion of students who start college at a two-year school matriculating to and earning STEM degrees from four-year schools, pre-STEM programs have great potential for broadening participation in baccalaureate STEM studies.
Example programs
The effectiveness of pre-STEM programs is being investigated by a consortium of schools in Missouri: Moberly Area Community College, St. Charles Community College, Metropolitan Community College, and Truman State University.
A larger group of schools met at the Belknap Springs Meetings in October 2009 to discuss the challenges and opportunities presented by STEM-focused partnerships between 2-year and 4-year schools. Each program represented a two-year school and a four-year school that were trying to increase the number of people who earn a baccalaureate degree in a STEM area through various means, some of which were pre-STEM programs. Other methods includes
Document 1:::
Physics education or physics teaching refers to the education methods currently used to teach physics. The occupation is called physics educator or physics teacher. Physics education research refers to an area of pedagogical research that seeks to improve those methods. Historically, physics has been taught at the high school and college level primarily by the lecture method together with laboratory exercises aimed at verifying concepts taught in the lectures. These concepts are better understood when lectures are accompanied with demonstration, hand-on experiments, and questions that require students to ponder what will happen in an experiment and why. Students who participate in active learning for example with hands-on experiments learn through self-discovery. By trial and error they learn to change their preconceptions about phenomena in physics and discover the underlying concepts. Physics education is part of the broader area of science education.
Ancient Greece
Aristotle wrote what is considered now as the first textbook of physics. Aristotle's ideas were taught unchanged until the Late Middle Ages, when scientists started making discoveries that didn't fit them. For example, Copernicus' discovery contradicted Aristotle's idea of an Earth-centric universe. Aristotle's ideas about motion weren't displaced until the end of the 17th century, when Newton published his ideas.
Today's physics students often think of physics concepts in Aristotelian terms, despite being taught only Newtonian concepts.
Hong Kong
High schools
In Hong Kong, physics is a subject for public examination. Local students in Form 6 take the public exam of Hong Kong Diploma of Secondary Education (HKDSE).
Compare to the other syllabus include GCSE, GCE etc. which learn wider and boarder of different topics, the Hong Kong syllabus is learning more deeply and more challenges with calculations. Topics are narrow down to a smaller amount compared to the A-level due to the insufficient teachi
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Physics First is an educational program in the United States, that teaches a basic physics course in the ninth grade (usually 14-year-olds), rather than the biology course which is more standard in public schools. This course relies on the limited math skills that the students have from pre-algebra and algebra I. With these skills students study a broad subset of the introductory physics canon with an emphasis on topics which can be experienced kinesthetically or without deep mathematical reasoning. Furthermore, teaching physics first is better suited for English Language Learners, who would be overwhelmed by the substantial vocabulary requirements of Biology.
Physics First began as an organized movement among educators around 1990, and has been slowly catching on throughout the United States. The most prominent movement championing Physics First is Leon Lederman's ARISE (American Renaissance in Science Education).
Many proponents of Physics First argue that turning this order around lays the foundations for better understanding of chemistry, which in turn will lead to more comprehension of biology. Due to the tangible nature of most introductory physics experiments, Physics First also lends itself well to an introduction to inquiry-based science education, where students are encouraged to probe the workings of the world in which they live.
The majority of high schools which have implemented "physics first" do so by way of offering two separate classes, at two separate levels: simple physics concepts in 9th grade, followed by more advanced physics courses in 11th or 12th grade. In schools with this curriculum, nearly all 9th grade students take a "Physical Science", or "Introduction to Physics Concepts" course. These courses focus on concepts that can be studied with skills from pre-algebra and algebra I. With these ideas in place, students then can be exposed to ideas with more physics related content in chemistry, and other science electives. After th
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Applied physics is the application of physics to solve scientific or engineering problems. It is usually considered a bridge or a connection between physics and engineering.
"Applied" is distinguished from "pure" by a subtle combination of factors, such as the motivation and attitude of researchers and the nature of the relationship to the technology or science that may be affected by the work. Applied physics is rooted in the fundamental truths and basic concepts of the physical sciences but is concerned with the utilization of scientific principles in practical devices and systems and with the application of physics in other areas of science and high technology.
Examples of research and development areas
Accelerator physics
Acoustics
Atmospheric physics
Biophysics
Brain–computer interfacing
Chemistry
Chemical physics
Differentiable programming
Artificial intelligence
Scientific computing
Engineering physics
Chemical engineering
Electrical engineering
Electronics
Sensors
Transistors
Materials science and engineering
Metamaterials
Nanotechnology
Semiconductors
Thin films
Mechanical engineering
Aerospace engineering
Astrodynamics
Electromagnetic propulsion
Fluid mechanics
Military engineering
Lidar
Radar
Sonar
Stealth technology
Nuclear engineering
Fission reactors
Fusion reactors
Optical engineering
Photonics
Cavity optomechanics
Lasers
Photonic crystals
Geophysics
Materials physics
Medical physics
Health physics
Radiation dosimetry
Medical imaging
Magnetic resonance imaging
Radiation therapy
Microscopy
Scanning probe microscopy
Atomic force microscopy
Scanning tunneling microscopy
Scanning electron microscopy
Transmission electron microscopy
Nuclear physics
Fission
Fusion
Optical physics
Nonlinear optics
Quantum optics
Plasma physics
Quantum technology
Quantum computing
Quantum cryptography
Renewable energy
Space physics
Spectroscopy
See also
Applied science
Applied mathematics
Engineering
Engineering Physics
High Technology
Document 4:::
The mathematical sciences are a group of areas of study that includes, in addition to mathematics, those academic disciplines that are primarily mathematical in nature but may not be universally considered subfields of mathematics proper.
Statistics, for example, is mathematical in its methods but grew out of bureaucratic and scientific observations, which merged with inverse probability and then grew through applications in some areas of physics, biometrics, and the social sciences to become its own separate, though closely allied, field. Theoretical astronomy, theoretical physics, theoretical and applied mechanics, continuum mechanics, mathematical chemistry, actuarial science, computer science, computational science, data science, operations research, quantitative biology, control theory, econometrics, geophysics and mathematical geosciences are likewise other fields often considered part of the mathematical sciences.
Some institutions offer degrees in mathematical sciences (e.g. the United States Military Academy, Stanford University, and University of Khartoum) or applied mathematical sciences (for example, the University of Rhode Island).
See also
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What branch of science is based on the modern atomic theory, which states that all matter is composed of atoms?
A. chemistry
B. psychology
C. biology
D. physics
Answer:
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|
sciq-3030
|
multiple_choice
|
Carbon fixation is the first step of what cycle involving light reactions?
|
[
"water cycle",
"sun cycle",
"calvin cycle",
"life cycle"
] |
C
|
Relavent Documents:
Document 0:::
The carbon cycle is that part of the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Other major biogeochemical cycles include the nitrogen cycle and the water cycle. Carbon is the main component of biological compounds as well as a major component of many minerals such as limestone. The carbon cycle comprises a sequence of events that are key to making Earth capable of sustaining life. It describes the movement of carbon as it is recycled and reused throughout the biosphere, as well as long-term processes of carbon sequestration (storage) to and release from carbon sinks.
To describe the dynamics of the carbon cycle, a distinction can be made between the fast and slow carbon cycle. The fast carbon cycle is also referred to as the biological carbon cycle. Fast carbon cycles can complete within years, moving substances from atmosphere to biosphere, then back to the atmosphere. Slow or geological cycles (also called deep carbon cycle) can take millions of years to complete, moving substances through the Earth's crust between rocks, soil, ocean and atmosphere.
Human activities have disturbed the fast carbon cycle for many centuries by modifying land use, and moreover with the recent industrial-scale mining of fossil carbon (coal, petroleum, and gas extraction, and cement manufacture) from the geosphere. Carbon dioxide in the atmosphere had increased nearly 52% over pre-industrial levels by 2020, forcing greater atmospheric and Earth surface heating by the Sun. The increased carbon dioxide has also caused a reduction in the ocean's pH value and is fundamentally altering marine chemistry. The majority of fossil carbon has been extracted over just the past half century, and rates continue to rise rapidly, contributing to human-caused climate change.
Main compartments
The carbon cycle was first described by Antoine Lavoisier and Joseph Priestley, and popularised by Humphry Davy. The g
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A biogeochemical cycle, or more generally a cycle of matter, is the movement and transformation of chemical elements and compounds between living organisms, the atmosphere, and the Earth's crust. Major biogeochemical cycles include the carbon cycle, the nitrogen cycle and the water cycle. In each cycle, the chemical element or molecule is transformed and cycled by living organisms and through various geological forms and reservoirs, including the atmosphere, the soil and the oceans. It can be thought of as the pathway by which a chemical substance cycles (is turned over or moves through) the biotic compartment and the abiotic compartments of Earth. The biotic compartment is the biosphere and the abiotic compartments are the atmosphere, lithosphere and hydrosphere.
For example, in the carbon cycle, atmospheric carbon dioxide is absorbed by plants through photosynthesis, which converts it into organic compounds that are used by organisms for energy and growth. Carbon is then released back into the atmosphere through respiration and decomposition. Additionally, carbon is stored in fossil fuels and is released into the atmosphere through human activities such as burning fossil fuels. In the nitrogen cycle, atmospheric nitrogen gas is converted by plants into usable forms such as ammonia and nitrates through the process of nitrogen fixation. These compounds can be used by other organisms, and nitrogen is returned to the atmosphere through denitrification and other processes. In the water cycle, the universal solvent water evaporates from land and oceans to form clouds in the atmosphere, and then precipitates back to different parts of the planet. Precipitation can seep into the ground and become part of groundwater systems used by plants and other organisms, or can runoff the surface to form lakes and rivers. Subterranean water can then seep into the ocean along with river discharges, rich with dissolved and particulate organic matter and other nutrients.
There are bio
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The evolution of photosynthesis refers to the origin and subsequent evolution of photosynthesis, the process by which light energy is used to assemble sugars from carbon dioxide and a hydrogen and electron source such as water. The process of photosynthesis was discovered by Jan Ingenhousz, a Dutch-born British physician and scientist, first publishing about it in 1779.
The first photosynthetic organisms probably evolved early in the evolutionary history of life and most likely used reducing agents such as hydrogen rather than water. There are three major metabolic pathways by which photosynthesis is carried out: C3 photosynthesis, C4 photosynthesis, and CAM photosynthesis. C3 photosynthesis is the oldest and most common form. A C3 plant uses the Calvin cycle for the initial steps that incorporate into organic material. A C4 plant prefaces the Calvin cycle with reactions that incorporate into four-carbon compounds. A CAM plant uses crassulacean acid metabolism, an adaptation for photosynthesis in arid conditions. C4 and CAM plants have special adaptations that save water.
Origin
Available evidence from geobiological studies of Archean (>2500 Ma) sedimentary rocks indicates that life existed 3500 Ma. Fossils of what are thought to be filamentous photosynthetic organisms have been dated at 3.4 billion years old, consistent with recent studies of photosynthesis. Early photosynthetic systems, such as those from green and purple sulfur and green and purple nonsulfur bacteria, are thought to have been anoxygenic, using various molecules as electron donors. Green and purple sulfur bacteria are thought to have used hydrogen and hydrogen sulfide as electron and hydrogen donors. Green nonsulfur bacteria used various amino and other organic acids. Purple nonsulfur bacteria used a variety of nonspecific organic and inorganic molecules. It is suggested that photosynthesis likely originated at low-wavelength geothermal light from acidic hydrothermal vents, Zn-tetrapyrroles w
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The Calvin cycle, light-independent reactions, bio synthetic phase, dark reactions, or photosynthetic carbon reduction (PCR) cycle of photosynthesis is a series of chemical reactions that convert carbon dioxide and hydrogen-carrier compounds into glucose. The Calvin cycle is present in all photosynthetic eukaryotes and also many photosynthetic bacteria. In plants, these reactions occur in the stroma, the fluid-filled region of a chloroplast outside the thylakoid membranes. These reactions take the products (ATP and NADPH) of light-dependent reactions and perform further chemical processes on them. The Calvin cycle uses the chemical energy of ATP and reducing power of NADPH from the light dependent reactions to produce sugars for the plant to use. These substrates are used in a series of reduction-oxidation reactions to produce sugars in a step-wise process; there is no direct reaction that converts several molecules of to a sugar. There are three phases to the light-independent reactions, collectively called the Calvin cycle: carboxylation, reduction reactions, and ribulose 1,5-bisphosphate (RuBP) regeneration.
Though it is called the "dark reaction", the Calvin cycle does not actually occur in the dark or during night time. This is because the process requires NADPH, which is short-lived and comes from the light-dependent reactions. In the dark, plants instead release sucrose into the phloem from their starch reserves to provide energy for the plant. The Calvin cycle thus happens when light is available independent of the kind of photosynthesis (C3 carbon fixation, C4 carbon fixation, and Crassulacean Acid Metabolism (CAM)); CAM plants store malic acid in their vacuoles every night and release it by day to make this process work.
Coupling to other metabolic pathways
The reactions of the Calvin cycle are closely coupled to the thylakoid electron transport chain as the energy required to reduce the carbon dioxide is provided by NADPH produced during the light de
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A pre-STEM program is a course of study at any two-year college that prepares a student to transfer to a four-year school to earn a bachelor's degree in a STEM field.
Overview
The concept of a pre-STEM program is being developed to address America's need for more college-trained professionals in science, technology, engineering, and mathematics (STEM). It is an innovation meant to fill a gap at community colleges that do not have 'major' degree paths that students identify with on their way to earning an Associates degree. Students must complete a considerable amount of STEM coursework before transferring from a two-year school to a four-year school and earn a baccalaureate degree in a STEM field. Schools with a pre-STEM program are able to identify those students and support them with STEM-specific academic and career advising, increasing the student's chances of going on to earn a STEM baccalaureate degree in a timely fashion.
With over 50% of America's college-bound students starting their college career at public or private two-year school, and with a very small proportion of students who start college at a two-year school matriculating to and earning STEM degrees from four-year schools, pre-STEM programs have great potential for broadening participation in baccalaureate STEM studies.
Example programs
The effectiveness of pre-STEM programs is being investigated by a consortium of schools in Missouri: Moberly Area Community College, St. Charles Community College, Metropolitan Community College, and Truman State University.
A larger group of schools met at the Belknap Springs Meetings in October 2009 to discuss the challenges and opportunities presented by STEM-focused partnerships between 2-year and 4-year schools. Each program represented a two-year school and a four-year school that were trying to increase the number of people who earn a baccalaureate degree in a STEM area through various means, some of which were pre-STEM programs. Other methods includes
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Carbon fixation is the first step of what cycle involving light reactions?
A. water cycle
B. sun cycle
C. calvin cycle
D. life cycle
Answer:
|
|
sciq-5692
|
multiple_choice
|
What makes soil and rock particles move gradually down the slope during each thaw?
|
[
"heat",
"rain",
"gravity",
"wind"
] |
C
|
Relavent Documents:
Document 0:::
The Géotechnique lecture is an biennial lecture on the topic of soil mechanics, organised by the British Geotechnical Association named after its major scientific journal Géotechnique.
This should not be confused with the annual BGA Rankine Lecture.
List of Géotechnique Lecturers
See also
Named lectures
Rankine Lecture
Terzaghi Lecture
External links
ICE Géotechnique journal
British Geotechnical Association
Document 1:::
Sediment transport is the movement of solid particles (sediment), typically due to a combination of gravity acting on the sediment, and the movement of the fluid in which the sediment is entrained. Sediment transport occurs in natural systems where the particles are clastic rocks (sand, gravel, boulders, etc.), mud, or clay; the fluid is air, water, or ice; and the force of gravity acts to move the particles along the sloping surface on which they are resting. Sediment transport due to fluid motion occurs in rivers, oceans, lakes, seas, and other bodies of water due to currents and tides. Transport is also caused by glaciers as they flow, and on terrestrial surfaces under the influence of wind. Sediment transport due only to gravity can occur on sloping surfaces in general, including hillslopes, scarps, cliffs, and the continental shelf—continental slope boundary.
Sediment transport is important in the fields of sedimentary geology, geomorphology, civil engineering, hydraulic engineering and environmental engineering (see applications, below). Knowledge of sediment transport is most often used to determine whether erosion or deposition will occur, the magnitude of this erosion or deposition, and the time and distance over which it will occur.
Mechanisms
Aeolian
Aeolian or eolian (depending on the parsing of æ) is the term for sediment transport by wind. This process results in the formation of ripples and sand dunes. Typically, the size of the transported sediment is fine sand (<1 mm) and smaller, because air is a fluid with low density and viscosity, and can therefore not exert very much shear on its bed.
Bedforms are generated by aeolian sediment transport in the terrestrial near-surface environment. Ripples and dunes form as a natural self-organizing response to sediment transport.
Aeolian sediment transport is common on beaches and in the arid regions of the world, because it is in these environments that vegetation does not prevent the presence and motion
Document 2:::
Vegetation and slope stability are interrelated by the ability of the plant life growing on slopes to both promote and hinder the stability of the slope. The relationship is a complex combination of the type of soil, the rainfall regime, the plant species present, the slope aspect, and the steepness of the slope. Knowledge of the underlying slope stability as a function of the soil type, its age, horizon development, compaction, and other impacts is a major underlying aspect of understanding how vegetation can alter the stability of the slope. There are four major ways in which vegetation influences slope stability: wind throwing, the removal of water, mass of vegetation (surcharge), and mechanical reinforcement of roots.
Wind throwing
Wind throw is the toppling of a tree due to the force of the wind, this exposes the root plate and adjacent soil beneath the tree and influences slope stability. Wind throw is factor when considering one tree on a slope, however it is of lesser importance when considering general slope stability for a body of trees as the wind forces involved represent a smaller percentage of the potential disturbing forces and the trees which are in the centre of the group will be sheltered by those on the outside.
Removal of water
Vegetation influences slope stability by removing water through transpiration. Transpiration is the vaporisation of liquid water contained in plant tissue and the vapour removal to the air. Water is drawn up from the roots and transported through the plant up to the leaves.
The major effect of transpiration is the reduction of soil pore water pressures which counteracts the loss of strength which occurs through wetting, this is most readily seen as a loss of moisture around trees. However it is not easy to rely on tree and shrub roots to remove water from slopes and consequently help ensure slope stability. The ability to transpire in wet conditions is severely reduced and therefore any increase in soil strength
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Frost heaving (or a frost heave) is an upwards swelling of soil during freezing conditions caused by an increasing presence of ice as it grows towards the surface, upwards from the depth in the soil where freezing temperatures have penetrated into the soil (the freezing front or freezing boundary). Ice growth requires a water supply that delivers water to the freezing front via capillary action in certain soils. The weight of overlying soil restrains vertical growth of the ice and can promote the formation of lens-shaped areas of ice within the soil. Yet the force of one or more growing ice lenses is sufficient to lift a layer of soil, as much as or more. The soil through which water passes to feed the formation of ice lenses must be sufficiently porous to allow capillary action, yet not so porous as to break capillary continuity. Such soil is referred to as "frost susceptible". The growth of ice lenses continually consumes the rising water at the freezing front. Differential frost heaving can crack road surfaces—contributing to springtime pothole formation—and damage building foundations. Frost heaves may occur in mechanically refrigerated cold-storage buildings and ice rinks.
Needle ice is essentially frost heaving that occurs at the beginning of the freezing season, before the freezing front has penetrated very far into the soil and there is no soil overburden to lift as a frost heave.
Mechanisms
Historical understanding of frost heaving
Urban Hjärne described frost effects in soil in 1694.
By 1930, Stephen Taber, head of the Department of Geology at the University of South Carolina, had disproved the hypothesis that frost heaving results from molar volume expansion with freezing of water already present in the soil prior to the onset of subzero temperatures, i.e. with little contribution from the migration of water within the soil.
Since the molar volume of water expands by about 9% as it changes phase from water to ice at its bulk freezing point, 9%
Document 4:::
Mass wasting, also known as mass movement, is a general term for the movement of rock or soil down slopes under the force of gravity. It differs from other processes of erosion in that the debris transported by mass wasting is not entrained in a moving medium, such as water, wind, or ice. Types of mass wasting include creep, solifluction, rockfalls, debris flows, and landslides, each with its own characteristic features, and taking place over timescales from seconds to hundreds of years. Mass wasting occurs on both terrestrial and submarine slopes, and has been observed on Earth, Mars, Venus, Jupiter's moon Io, and on many other bodies in the Solar System.
Subsidence is sometimes regarded as a form of mass wasting. A distinction is then made between mass wasting by subsidence, which involves little horizontal movement, and mass wasting by slope movement.
Rapid mass wasting events, such as landslides, can be deadly and destructive. More gradual mass wasting, such as soil creep, poses challenges to civil engineering, as creep can deform roadways and structures and break pipelines. Mitigation methods include slope stabilization, construction of walls, catchment dams, or other structures to contain rockfall or debris flows, afforestation, or improved drainage of source areas.
Types
Mass wasting is a general term for any process of erosion that is driven by gravity and in which the transported soil and rock is not entrained in a moving medium, such as water, wind, or ice. The presence of water usually aids mass wasting, but the water is not abundant enough to be regarded as a transporting medium. Thus, the distinction between mass wasting and stream erosion lies between a mudflow (mass wasting) and a very muddy stream (stream erosion), without a sharp dividing line. Many forms of mass wasting are recognized, each with its own characteristic features, and taking place over timescales from seconds to hundreds of years.
Based on how the soil, regolith or rock moves dow
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What makes soil and rock particles move gradually down the slope during each thaw?
A. heat
B. rain
C. gravity
D. wind
Answer:
|
|
sciq-2989
|
multiple_choice
|
Which hormone is secreted by the pancreas in a human body?
|
[
"growth hormone",
"progesterone",
"estrogen",
"insulin"
] |
D
|
Relavent Documents:
Document 0:::
Heterocrine glands (or composite glands) are the glands which function as both exocrine gland and endocrine gland. These glands exhibit a unique and diverse secretory function encompassing the release of proteins and non-proteinaceous compounds, endocrine and exocrine secretions into both the bloodstream and ducts respectively, thereby bridging the realms of internal and external communication within the body. This duality allows them to serve crucial roles in regulating various physiological processes and maintaining homeostasis. These include the gonads (testes and ovaries), pancreas and salivary glands.
Pancreas releases digestive enzymes into the small intestine via ducts (exocrine) and secretes insulin and glucagon into the bloodstream (endocrine) to regulate blood sugar level. Testes produce sperm, which is released through ducts (exocrine), and they also secrete testosterone into the bloodstream (endocrine). Similarly, ovaries release ova through ducts (exocrine) and produce estrogen and progesterone (endocrine). Salivary glands secrete saliva through ducts to aid in digestion (exocrine) and produce epidermal growth factor and insulin-like growth factor (endocrine).
Anatomy
Heterocrine glands typically have a complex structure that enables them to produce and release different types of secretions. The two primary components of these glands are:
Endocrine component: Heterocrine glands produce hormones, which are chemical messengers that travel through the bloodstream to target organs or tissues. These hormones play a vital role in regulating numerous physiological processes, such as metabolism, growth, and the immune response.
Exocrine component: In addition to their endocrine function, heterocrine glands secrete substances directly into ducts or cavities, which can be released through various body openings. These exocrine secretions can include enzymes, mucus, and other substances that aid in digestion, lubrication, or protection.
Characteristics and Func
Document 1:::
Glucagon/gastric inhibitory polypeptide/secretin/vasoactive intestinal peptide hormones are a family of evolutionarily related peptide hormones that regulate activity of G-protein-coupled receptors from the secretin receptor family.
A number of polypeptidic hormones, mainly expressed in the intestine or the pancreas, belong to a group of these structurally related peptides. One such hormone, glucagon, is widely distributed and produced in the alpha-cells of pancreatic islets. It affects glucose metabolism in the liver by inhibiting glycogen synthesis, stimulating glycogenolysis and enhancing gluconeogenesis. It also increases mobilisation of glucose, free fatty acids, and ketone bodies, which are metabolites produced in excess in diabetes mellitus. Glucagon is produced, like other peptide hormones, as part of a larger precursor (preproglucagon), which is cleaved to produce glucagon, glucagon-like protein I, glucagon-like protein II, and glicentin. The structure of glucagon itself is fully conserved in all mammalian species in which it has been studied. Other members of the structurally similar group include secretin, gastric inhibitory peptide, vasoactive intestinal peptide, prealbumin, peptide HI-27, and growth hormone releasing factor.
Human hormones from this family
ADCYAP1; GCG; GHRH; GIP; SCT; VIP;
Document 2:::
The following is a list of hormones found in Homo sapiens. Spelling is not uniform for many hormones. For example, current North American and international usage uses estrogen and gonadotropin, while British usage retains the Greek digraph in oestrogen and favours the earlier spelling gonadotrophin.
Hormone listing
Steroid
Document 3:::
History
HxA3 and HxB3 were first identified, named, shown to have biological activity in stimulating insulin secretion in cultured rat pancreatic islets of Langerhans in Canada in 1984 by CR Pace-Asciak and JM Martin. Shortly thereafter, Pace-Asciak identified, named, and showed to have insulin secretagogue activity HxA4
Document 4:::
Uterine glands or endometrial glands are tubular glands, lined by a simple columnar epithelium, found in the functional layer of the endometrium that lines the uterus. Their appearance varies during the menstrual cycle. During the proliferative phase, uterine glands appear long due to estrogen secretion by the ovaries. During the secretory phase, the uterine glands become very coiled with wide lumens and produce a glycogen-rich secretion known as histotroph or uterine milk. This change corresponds with an increase in blood flow to spiral arteries due to increased progesterone secretion from the corpus luteum. During the pre-menstrual phase, progesterone secretion decreases as the corpus luteum degenerates, which results in decreased blood flow to the spiral arteries. The functional layer of the uterus containing the glands becomes necrotic, and eventually sloughs off during the menstrual phase of the cycle.
They are of small size in the unimpregnated uterus, but shortly after impregnation become enlarged and elongated, presenting a contorted or waved appearance.
Function
Hormones produced in early pregnancy stimulate the uterine glands to secrete a number of substances to give nutrition and protection to the embryo and fetus, and the fetal membranes. These secretions are known as histiotroph, alternatively histotroph, and also as uterine milk. Important uterine milk proteins are glycodelin-A, and osteopontin.
Some secretory components from the uterine glands are taken up by the secondary yolk sac lining the exocoelomic cavity during pregnancy, and may thereby assist in providing fetal nutrition.
Additional images
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Which hormone is secreted by the pancreas in a human body?
A. growth hormone
B. progesterone
C. estrogen
D. insulin
Answer:
|
|
sciq-1193
|
multiple_choice
|
Oncogenes are involved in the formation of what disease?
|
[
"heart disease",
"cancer",
"colds",
"autoimmune disease"
] |
B
|
Relavent Documents:
Document 0:::
Oncogene is a peer-reviewed scientific journal published under the Nature Portfolio addressing cancer cell genetics and the structure and function of oncogenes. The journal has editorial office in London, England under the publishing company Springer Nature. The journal was established in 1987. An open access online-only sister journal, Oncogenesis, was established in 2012 by Douglas R. Green, who was then Oncogene'''s editor-in-chief.Oncogene received a 2021 impact factor of 8.756 and received Journal Citation Reports rankings of 38th out of 245 journals in the category Oncology, 16th out of 175 in the category Genetics & Heredity, 41st out of 194 in the category Cell Biology, and 40th out of 296 in the category Biochemistry & Molecular Biology''.
The current editors-in-chief are George Miller and Justin Stebbing.
Abstracting and indexing
The journal is abstracted and indexed in:
EBSCO Discovery Service, Google Scholar, OCLC, Summon by ProQuest, BIOSIS, Current Contents/Life Sciences, Science Citation Index, Science Citation Index Expanded (SciSearch), SCOPUS, EBSCO Academic Search, EBSCO Advanced Placement Source, EBSCO Agriculture Plus, EBSCO Biomedical Reference Collection, EBSCO Science & Technology Collection, EBSCO STM Source, EBSCO TOC Premier, and INIS Atomindex.
See also
Nature Research
List of Nature Research journals
Document 1:::
Oncogene addiction is a process in which cancers with genetic, epigenetic, or chromosomal irregularities become dependent on one or several genes for maintenance and survival. As a result, cancer cells rely on continuous signaling from these oncogenes for their survival. The term was coined in 2002 by American physician I. Bernard Weinstein.
Examples
A prime example of a cancer that exhibits oncogene addiction is chronic myelogenous leukemia (CML), which is driven by a mutant oncogene known as the Philadelphia chromosome. CML has been called the "poster-child disease for oncogene addiction". Other examples include gastrointestinal stromal tumor, which can be addicted to the gene KIT; melanoma, which can be addicted to the gene BRAF; and non-small-cell lung carcinoma, which can be addicted to the gene EGFR.
Treatment
Oncogene addiction can be treated by using enzyme inhibitor therapy. Examples of inhibitors that have been used to block oncogenes and disrupt oncogene addiction include imatinib, nilotinib, dasatinib, and ponatinib, among others. While initial treatment may have striking, positive results for controlling the cancer, chronic treatment often results in acquired resistance to the drugs and relapse. Oncogene inhibition typically results progression-free survival of a few months, meaning most cancer treatment ultimately relies on frontline chemotherapy. The notable exception is the success of inhibitor therapy in treating CML. Inhibitor therapy has been so successful in this disease, the average progression-free survival time is still unknown, as it has not been reached in more than ten years of followup.
More recent understanding of inhibitor resistance is that inhibition of a single gene can cause the signaling pathways to rewire. This rewiring can rescue the downstream processes that signal to and maintain the cancer.
Document 2:::
Malignant transformation is the process by which cells acquire the properties of cancer. This may occur as a primary process in normal tissue, or secondarily as malignant degeneration of a previously existing benign tumor.
Causes
There are many causes of primary malignant transformation, or tumorigenesis. Most human cancers in the United States are caused by external factors, and these factors are largely avoidable. These factors were summarized by Doll and Peto in 1981, and were still considered to be valid in 2015. These factors are listed in the table.
a Reproductive and sexual behaviors include: number of partners; age at first menstruation; zero versus one or more live births
Examples of diet-related malignant transformation
Diet and colon cancer
Colon cancer provides one example of the mechanisms by which diet, the top factor listed in the table, is an external factor in cancer. The Western diet of African Americans in the United States is associated with a yearly colon cancer rate of 65 per 100,000 individuals, while the high fiber/low fat diet of rural Native Africans in South Africa is associated with a yearly colon cancer rate of <5 per 100,000. Feeding the Western diet for two weeks to Native Africans increased their secondary bile acids, including carcinogenic deoxycholic acid, by 400%, and also changed the colonic microbiota. Evidence reviewed by Sun and Kato indicates that differences in human colonic microbiota play an important role in the progression of colon cancer.
Diet and lung cancer
A second example, relating a dietary component to a cancer, is illustrated by lung cancer. Two large population-based studies were performed, one in Italy and one in the United States. In Italy, the study population consisted of two cohorts: the first, 1721 individuals diagnosed with lung cancer and no severe disease, and the second, 1918 control individuals with absence of lung cancer history or any advanced diseases. All individuals filled out a
Document 3:::
Cancer is caused by genetic changes leading to uncontrolled cell growth and tumor formation. The basic cause of sporadic (non-familial) cancers is DNA damage and genomic instability. A minority of cancers are due to inherited genetic mutations. Most cancers are related to environmental, lifestyle, or behavioral exposures. Cancer is generally not contagious in humans, though it can be caused by oncoviruses and cancer bacteria. The term "environmental", as used by cancer researchers, refers to everything outside the body that interacts with humans. The environment is not limited to the biophysical environment (e.g. exposure to factors such as air pollution or sunlight), but also includes lifestyle and behavioral factors.
Over one third of cancer deaths worldwide (and about 75–80% in the United States) are potentially avoidable by reducing exposure to known factors. Common environmental factors that contribute to cancer death include exposure to different chemical and physical agents (tobacco use accounts for 25–30% of cancer deaths), environmental pollutants, diet and obesity (30–35%), infections (15–20%), and radiation (both ionizing and non-ionizing, up to 10%). These factors act, at least partly, by altering the function of genes within cells. Typically many such genetic changes are required before cancer develops. Aging has been repeatedly and consistently regarded as an important aspect to consider when evaluating the risk factors for the development of particular cancers. Many molecular and cellular changes involved in the development of cancer accumulate during the aging process and eventually manifest as cancer.
Genetics
Although there are over 50 identifiable hereditary forms of cancer, less than 0.3% of the population are carriers of a cancer-related genetic mutation and these make up less than 3–10% of all cancer cases. The vast majority of cancers are non-hereditary ("sporadic cancers"). Hereditary cancers are primarily caused by an inherited genetic d
Document 4:::
Margaret L. Kripke is an American immunologist. She is an expert in photoimmunology and the immunology of skin cancers. She earned a BS and MS in bacteriology, and a Ph.D in immunology, at the University of California at Berkeley.
She founded the department of immunology at The University of Texas M. D. Anderson Cancer Center in 1983, and served as the cancer center's executive vice president and chief academic officer until her retirement in 2007. After her retirement, Kripke served as special advisor to the provost.
From 1993 to 1994, Kripke served as president of the American Association for Cancer Research.
In 2008, M. D. Anderson established the Margaret Kripke Legend Award "to honor individuals who have enhanced the careers of women in cancer medicine and cancer science".
She served on the President's Cancer Panel from 2003 to 2011. The panel's 2006-2007 report, Promoting Healthy Lifestyles, urged "that the influence of the tobacco industry – particularly on America’s children – be weakened
through strict Federal regulation of tobacco product sales and marketing". The panel's 2008-2009 report, Reducing Environmental Cancer Risk: What We Can Do Now, "for the first time highlights the contribution of environmental contaminants to the development of cancer". A 2021 video describes how Dr. Kripke came to rethink her assumptions about the causes of cancer.
In 2013, she was named a Fellow of the American Association for Cancer Research Academy.
From 2012 through 2016, she was the chief scientific officer of the Cancer Prevention and Research Institute of Texas.
She has served on the board of directors of Silent Spring Institute.
In 2020, Kripke called upon the National Cancer Institute to publish information about cancer risks from exposure to chemicals in the environment.
Bibliography
Publication Lists
JSTOR.org
Researchgate.net
Google Scholar
Books
Google Books list
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Oncogenes are involved in the formation of what disease?
A. heart disease
B. cancer
C. colds
D. autoimmune disease
Answer:
|
|
sciq-5801
|
multiple_choice
|
What is the tail bone an example of?
|
[
"vestigial structure",
"primordial structure",
"parasitic structure",
"invertebrate structure"
] |
A
|
Relavent Documents:
Document 0:::
The coccyx (: coccyges or coccyxes), commonly referred to as the tailbone, is the final segment of the vertebral column in all apes, and analogous structures in certain other mammals such as horses. In tailless primates (e.g. humans and other great apes) since Nacholapithecus (a Miocene hominoid), the coccyx is the remnant of a vestigial tail. In animals with bony tails, it is known as tailhead or dock, in bird anatomy as tailfan. It comprises three to five separate or fused coccygeal vertebrae below the sacrum, attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between the sacrum and the coccyx.
Structure
The coccyx is formed of three, four or five rudimentary vertebrae. It articulates superiorly with the sacrum. In each of the first three segments may be traced a rudimentary body and articular and transverse processes; the last piece (sometimes the third) is a mere nodule of bone. The transverse processes are most prominent and noticeable on the first coccygeal segment. All the segments lack pedicles, laminae and spinous processes. The first segment is the largest; it resembles the lowest sacral vertebra, and often exists as a separate piece; the remaining ones diminish in size rostrally.
Most anatomy books incorrectly state that the coccyx is normally fused in adults. It has been shown that the coccyx may, in some people, consist of up to five separate bony segments, the most common configuration being two or three segments.
Surfaces
The anterior surface is slightly concave and marked with three transverse grooves which indicate the junctions of the different segments. It gives attachment to the anterior sacrococcygeal ligament and the levatores ani and supports part of the rectum. The posterior surface is convex, marked by transverse grooves similar to those on the anterior surface, and presents on either side a linear row of tubercles – the undeveloped articular processes of the coccygeal ve
Document 1:::
Work
He is an associate professor of anatomy, Department of Anatomy, Howard University College of Medicine (US). He was among the most cited/influential anatomists in 2019.
Books
Single author or co-author books
DIOGO, R. (2021). Meaning of Life, Human Nature and Delusions - How Tales about Love, Sex, Races, Gods and Progress Affect Us and Earth's Splendor. Springer (New York, US).
MONTERO, R., ADESOMO, A. & R. DIOGO (2021). On viruses, pandemics, and us: a developing story [De virus, pandemias y nosotros: una historia en desarollo]. Independently published, Tucuman, Argentina. 495 pages.
DIOGO, R., J. ZIERMANN, J. MOLNAR, N. SIOMAVA & V. ABDALA (2018). Muscles of Chordates: development, homologies and evolution. Taylor & Francis (Oxford, UK). 650 pages.
DIOGO, R., B. SHEARER, J. M. POTAU, J. F. PASTOR, F. J. DE PAZ, J. ARIAS-MARTORELL, C. TURCOTTE, A. HAMMOND, E. VEREECKE, M. VANHOOF, S. NAUWELAERTS & B. WOOD (2017). Photographic and descriptive musculoskeletal atlas of bonobos - with notes on the weight, attachments, variations, and innervation of the muscles and comparisons with common chimpanzees and humans. Springer (New York, US). 259 pages.
DIOGO, R. (2017). Evolution driven by organismal behavior: a unifying view of life, function, form, mismatches and trends. Springer
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Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times. Anatomy is inherently tied to developmental biology, embryology, comparative anatomy, evolutionary biology, and phylogeny, as these are the processes by which anatomy is generated, both over immediate and long-term timescales. Anatomy and physiology, which study the structure and function of organisms and their parts respectively, make a natural pair of related disciplines, and are often studied together. Human anatomy is one of the essential basic sciences that are applied in medicine.
Anatomy is a complex and dynamic field that is constantly evolving as new discoveries are made. In recent years, there has been a significant increase in the use of advanced imaging techniques, such as MRI and CT scans, which allow for more detailed and accurate visualizations of the body's structures.
The discipline of anatomy is divided into macroscopic and microscopic parts. Macroscopic anatomy, or gross anatomy, is the examination of an animal's body parts using unaided eyesight. Gross anatomy also includes the branch of superficial anatomy. Microscopic anatomy involves the use of optical instruments in the study of the tissues of various structures, known as histology, and also in the study of cells.
The history of anatomy is characterized by a progressive understanding of the functions of the organs and structures of the human body. Methods have also improved dramatically, advancing from the examination of animals by dissection of carcasses and cadavers (corpses) to 20th-century medical imaging techniques, including X-ray, ultrasound, and magnetic resonance imaging.
Etymology and definition
Derived from the Greek anatomē "dissection" (from anatémnō "I cut up, cut open" from ἀνά aná "up", and τέμνω té
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The protocerebrum is the first segment of the panarthropod brain.
Recent studies suggest that it comprises two regions.
Region associated with the expression of six3
six3 is a transcription factor that marks the anteriormost part of the developing body in a whole host of Metazoa.
In the panarthropod brain, the anteriormost (rostralmost) part of the germband expresses six3. This region is described as medial, and corresponds to the annelid prostomium.
In arthropods, it contains the pars intercerebralis and pars lateralis.
six3 is associated with the euarthropod labrum and the onychophoran frontal appendages (antennae).
Region associated with the expression of orthodenticle
The other region expresses homologues of orthodenticle, Otx or otd. This region is more caudal and lateral, and bears the eyes.
Orthodenticle is associated with the protocerebral bridge, part of the central complex, traditionally a marker of the prosocerebrum.
In the annelid brain, Otx expression characterises the peristomium, but also creeps forwards into the regions of the prostomium that bear the larval eyes.
Names of regions
Inconsistent use of the terms archicerebrum and the prosocerebrum makes them confusing.
The regions were defined by Siewing (1963): the archicerebrum as containing the ocular lobes and the mushroom bodies (= corpora pedunculata), and the prosocerebrum as comprising the central complex.
The archicerebrum has traditionally been equated with the anteriormost, 'non-segmental' part of the protocerebrum, equivalent to the acron in older terminology.
The prosocerebrum is then equivalent to the 'segmental' part of the protocerebrum, bordered by segment polarity genes such as engrailed, and (on one interpretation) bearing modified segmental appendages (= camera-type eyes).
But Urbach and Technau (2003) complicate the matter by seeing the prosocerebrum (central complex) + labrum as the anteriormost region
Strausfeld 2016 identifies the anteriormost part of the b
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Myomeres are blocks of skeletal muscle tissue arranged in sequence, commonly found in aquatic chordates. Myomeres are separated from adjacent myomeres by connective fascia (myosepta) and most easily seen in larval fishes or in the olm. Myomere counts are sometimes used for identifying specimens, since their number corresponds to the number of vertebrae in the adults. Location varies, with some species containing these only near the tails, while some have them located near the scapular or pelvic girdles. Depending on the species, myomeres could be arranged in an epaxial or hypaxial manner. Hypaxial refers to ventral muscles and related structures while epaxial refers to more dorsal muscles. The horizontal septum divides these two regions in vertebrates from cyclostomes to gnathostomes. In terrestrial chordates, the myomeres become fused as well as indistinct, due to the disappearance of myosepta.
Shape
The shape of myomeres varies by species. Myomeres are commonly zig-zag, "V" (lancelets), "W" (fishes), or straight (tetrapods)– shaped muscle fibers. Generally, cyclostome myomeres are arranged in vertical strips while those of jawed fishes are folded in a complex matter due to swimming capability evolution. Specifically, myomeres of elasmobranchs and eels are “W”-shaped. Contrastingly, myomeres of tetrapods run vertically and do not display complex folding. Another species with simply-lain myomeres are mudpuppies. Myomeres overlap each other in succession, meaning myomere activation also allows neighboring myomeres to activate.
Myomeres are made up of myoglobin-rich dark muscle as well as white muscle. Dark muscle, generally, functions as slow-twitch muscle fibers while white muscle is composed of fast-twitch fibers.
Function
Specifically, three types of myomeres in fish-like chordates include amphioxine (lancelet), cyclostomine (jawless fish), and gnathostomine (jawed fish). A common function shared by all of these is that they function to flex the body lateral
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What is the tail bone an example of?
A. vestigial structure
B. primordial structure
C. parasitic structure
D. invertebrate structure
Answer:
|
|
sciq-11153
|
multiple_choice
|
When the monocilia are defective, what is disrupted?
|
[
"inhibiting",
"signaling",
"triggering",
"predicting"
] |
B
|
Relavent Documents:
Document 0:::
The SAT Subject Test in Biology was the name of a one-hour multiple choice test given on biology by the College Board. A student chose whether to take the test depending upon college entrance requirements for the schools in which the student is planning to apply. Until 1994, the SAT Subject Tests were known as Achievement Tests; and from 1995 until January 2005, they were known as SAT IIs. Of all SAT subject tests, the Biology E/M test was the only SAT II that allowed the test taker a choice between the ecological or molecular tests. A set of 60 questions was taken by all test takers for Biology and a choice of 20 questions was allowed between either the E or M tests. This test was graded on a scale between 200 and 800. The average for Molecular is 630 while Ecological is 591.
On January 19 2021, the College Board discontinued all SAT Subject tests, including the SAT Subject Test in Biology E/M. This was effective immediately in the United States, and the tests were to be phased out by the following summer for international students. This was done as a response to changes in college admissions due to the impact of the COVID-19 pandemic on education.
Format
This test had 80 multiple-choice questions that were to be answered in one hour. All questions had five answer choices. Students received one point for each correct answer, lost ¼ of a point for each incorrect answer, and received 0 points for questions left blank. The student's score was based entirely on his or her performance in answering the multiple-choice questions.
The questions covered a broad range of topics in general biology. There were more specific questions related respectively on ecological concepts (such as population studies and general Ecology) on the E test and molecular concepts such as DNA structure, translation, and biochemistry on the M test.
Preparation
The College Board suggested a year-long course in biology at the college preparatory level, as well as a one-year course in algebra, a
Document 1:::
Single Best Answer (SBA or One Best Answer) is a written examination form of multiple choice questions used extensively in medical education.
Structure
A single question is posed with typically five alternate answers, from which the candidate must choose the best answer. This method avoids the problems of past examinations of a similar form described as Single Correct Answer. The older form can produce confusion where more than one of the possible answers has some validity. The newer form makes it explicit that more than one answer may have elements that are correct, but that one answer will be superior.
Prior to the widespread introduction of SBAs into medical education, the typical form of examination was true-false multiple choice questions. But during the 2000s, educators found that SBAs would be superior.
Document 2:::
Several universities have designed interdisciplinary courses with a focus on human biology at the undergraduate level. There is a wide variation in emphasis ranging from business, social studies, public policy, healthcare and pharmaceutical research.
Americas
Human Biology major at Stanford University, Palo Alto (since 1970)
Stanford's Human Biology Program is an undergraduate major; it integrates the natural and social sciences in the study of human beings. It is interdisciplinary and policy-oriented and was founded in 1970 by a group of Stanford faculty (Professors Dornbusch, Ehrlich, Hamburg, Hastorf, Kennedy, Kretchmer, Lederberg, and Pittendrigh). It is a very popular major and alumni have gone to post-graduate education, medical school, law, business and government.
Human and Social Biology (Caribbean)
Human and Social Biology is a Level 4 & 5 subject in the secondary and post-secondary schools in the Caribbean and is optional for the Caribbean Secondary Education Certification (CSEC) which is equivalent to Ordinary Level (O-Level) under the British school system. The syllabus centers on structure and functioning (anatomy, physiology, biochemistry) of human body and the relevance to human health with Caribbean-specific experience. The syllabus is organized under five main sections: Living organisms and the environment, life processes, heredity and variation, disease and its impact on humans, the impact of human activities on the environment.
Human Biology Program at University of Toronto
The University of Toronto offers an undergraduate program in Human Biology that is jointly offered by the Faculty of Arts & Science and the Faculty of Medicine. The program offers several major and specialist options in: human biology, neuroscience, health & disease, global health, and fundamental genetics and its applications.
Asia
BSc (Honours) Human Biology at All India Institute of Medical Sciences, New Delhi (1980–2002)
BSc (honours) Human Biology at AIIMS (New
Document 3:::
GRE Subject Biochemistry, Cell and Molecular Biology was a standardized exam provided by ETS (Educational Testing Service) that was discontinued in December 2016. It is a paper-based exam and there are no computer-based versions of it. ETS places this exam three times per year: once in April, once in October and once in November. Some graduate programs in the United States recommend taking this exam, while others require this exam score as a part of the application to their graduate programs. ETS sends a bulletin with a sample practice test to each candidate after registration for the exam. There are 180 questions within the biochemistry subject test.
Scores are scaled and then reported as a number between 200 and 990; however, in recent versions of the test, the maximum and minimum reported scores have been 760 (corresponding to the 99 percentile) and 320 (1 percentile) respectively. The mean score for all test takers from July, 2009, to July, 2012, was 526 with a standard deviation of 95.
After learning that test content from editions of the GRE® Biochemistry, Cell and Molecular Biology (BCM) Test has been compromised in Israel, ETS made the decision not to administer this test worldwide in 2016–17.
Content specification
Since many students who apply to graduate programs in biochemistry do so during the first half of their fourth year, the scope of most questions is largely that of the first three years of a standard American undergraduate biochemistry curriculum. A sampling of test item content is given below:
Biochemistry (36%)
A Chemical and Physical Foundations
Thermodynamics and kinetics
Redox states
Water, pH, acid-base reactions and buffers
Solutions and equilibria
Solute-solvent interactions
Chemical interactions and bonding
Chemical reaction mechanisms
B Structural Biology: Structure, Assembly, Organization and Dynamics
Small molecules
Macromolecules (e.g., nucleic acids, polysaccharides, proteins and complex lipids)
Supramolecular complexes (e.g.
Document 4:::
The School of Biological Sciences is one of the academic units of the University of California, Irvine (UCI). The school is divided into four departments: developmental and cell biology, ecology and evolutionary biology, molecular biology and biochemistry, and neurobiology and behavior. With over 3,700 students it is in the top four largest schools in the university.<ref></http://grad-schools.usnews.rankingsandreviews.com/best-graduate-schools/top-medical-schools/research-rankings/page+2> In 2013, the Francisco J. Ayala School of Biological Sciences contained 19.4 percent of the student population
</ref>
It is consistently ranked in the top one hundred in U.S. News & World Report’s yearly list of best graduate schools.
History
The School of Biological Sciences first opened in 1965 at the University of California, Irvine and was one of the first schools founded when the university campus opened. The school's founding Dean, Edward A. Steinhaus, had four founding department chairs and started out with 17 professors.
On March 12, 2014, the School was officially renamed after UCI professor and donor Francisco J. Ayala by then-Chancellor Michael V. Drake. Ayala had previously pledged to donate $10 million to the School of Biological Sciences in 2011. The school reverted to its previous name in June 2018, after a university investigation confirmed that Ayala had sexually harassed at least four women colleagues and graduate students.
Notes
External links
University of California, Irvine
Biology education
Science education in the United States
Science and technology in Greater Los Angeles
University subdivisions in California
Educational institutions established in 1965
1965 establishments in California
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
When the monocilia are defective, what is disrupted?
A. inhibiting
B. signaling
C. triggering
D. predicting
Answer:
|
|
sciq-5773
|
multiple_choice
|
Fibrous root systems have many small branching roots called what?
|
[
"fibrous roots",
"taproots",
"vines",
"tendrils"
] |
A
|
Relavent Documents:
Document 0:::
The quiescent centre is a group of cells, up to 1,000 in number, in the form of a hemisphere, with the flat face toward the root tip of vascular plants. It is a region in the apical meristem of a root where cell division proceeds very slowly or not at all, but the cells are capable of resuming meristematic activity when the tissue surrounding them is damaged.
Cells of root apical meristems do not all divide at the same rate. Determinations of relative rates of DNA synthesis show that primary roots of Zea, Vicia and Allium have quiescent centres to the meristems, in which the cells divide rarely or never in the course of normal root growth (Clowes, 1958). Such a quiescent centre includes the cells at the apices of the histogens of both stele and cortex. Its presence can be deduced from the anatomy of the apex in Zea (Clowes, 1958), but not in the other species which lack discrete histogens.
History
In 1953, during the course of analysing the organization and function of the root apices, Frederick Albert Lionel Clowes (born 10 September 1921), at the School of Botany (now Department of Plant Sciences), University of Oxford, proposed the term ‘cytogenerative centre’ to denote ‘the region of an apical meristem from which all future cells are derived’. This term had been suggested to him by Mr Harold K. Pusey, a lecturer in embryology at the Department of Zoology and Comparative Anatomy at the same university. The 1953 paper of Clowes reported results of his experiments on Fagus sylvatica and Vicia faba, in which small oblique and wedge-shaped excisions were made at the tip of the primary root, at the most distal level of the root body, near the boundary with the root cap. The results of these experiments were striking and showed that: the root which grew on following the excision was normal at the undamaged meristem side; the nonexcised meristem portion contributed to the regeneration of the excised portion; the regenerated part of the root had abnormal patterning and
Document 1:::
Basal shoots, root sprouts, adventitious shoots, and suckers are words for various kinds of shoots that grow from adventitious buds on the base of a tree or shrub, or from adventitious buds on its roots. Shoots that grow from buds on the base of a tree or shrub are called basal shoots; these are distinguished from shoots that grow from adventitious buds on the roots of a tree or shrub, which may be called root sprouts or suckers. A plant that produces root sprouts or runners is described as surculose. Water sprouts produced by adventitious buds may occur on the above-ground stem, branches or both of trees and shrubs. Suckers are shoots arising underground from the roots some distance from the base of a tree or shrub.
In botany and ecology
In botany, a root sprout or sucker is a severable plant that grows not from a seed but from the meristem of a root at the base of or a certain distance from the original tree or shrub. Root sprouts may emerge a substantial distance from the base of the originating plant, are a form of vegetative dispersal, and may form a patch that constitutes a habitat in which that surculose plant is the dominant species. Root sprouts also may grow from the roots of trees that have been felled. Tree roots ordinarily grow outward from their trunks a distance of 1.5 to 2 times their heights, and therefore root sprouts can emerge a substantial distance from the trunk.
This is a phenomenon of natural "asexual reproduction", also denominated "vegetative reproduction". It is a strategy of plant propagation. The complex of clonal individuals and the originating plant comprise a single genetic individual, i. e., a genet. The individual root sprouts are clones of the original plant, and each has a genome that is identical to that of the originating plant from which it grew. Many species of plants reproduce through vegetative reproduction, e. g. Canada thistle, cherry, apple, guava, privet, hazel, lilac, tree of heaven, and Asimina triloba.
The root s
Document 2:::
Micropropagation or tissue culture is the practice of rapidly multiplying plant stock material to produce many progeny plants, using modern plant tissue culture methods.
Micropropagation is used to multiply a wide variety of plants, such as those that have been genetically modified or bred through conventional plant breeding methods. It is also used to provide a sufficient number of plantlets for planting from seedless plants, plants that do not respond well to vegetative reproduction or where micropropagation is the cheaper means of propagating (e.g. Orchids). Cornell University botanist Frederick Campion Steward discovered and pioneered micropropagation and plant tissue culture in the late 1950s and early 1960s.
Steps
In short, steps of micropropagation can be divided into four stages:
Selection of mother plant
Multiplication
Rooting and acclimatizing
Transfer new plant to soil
Selection of mother plant
Micropropagation begins with the selection of plant material to be propagated. The plant tissues are removed from an intact plant in a sterile condition. Clean stock materials that are free of viruses and fungi are important in the production of the healthiest plants. Once the plant material is chosen for culture, the collection of explant(s) begins and is dependent on the type of tissue to be used; including stem tips, anthers, petals, pollen and other plant tissues. The explant material is then surface sterilized, usually in multiple courses of bleach and alcohol washes, and finally rinsed in sterilized water. This small portion of plant tissue, sometimes only a single cell, is placed on a growth medium, typically containing Macro and micro nutrients, water, sucrose as an energy source and one or more plant growth regulators (plant hormones). Usually the medium is thickened with a gelling agent, such as agar, to create a gel which supports the explant during growth. Some plants are easily grown on simple media, but others require more complicated media f
Document 3:::
In botany, a plant shoot consists of any plant stem together with its appendages like, leaves and lateral buds, flowering stems, and flower buds. The new growth from seed germination that grows upward is a shoot where leaves will develop. In the spring, perennial plant shoots are the new growth that grows from the ground in herbaceous plants or the new stem or flower growth that grows on woody plants.
In everyday speech, shoots are often synonymous with stems. Stems, which are an integral component of shoots, provide an axis for buds, fruits, and leaves.
Young shoots are often eaten by animals because the fibers in the new growth have not yet completed secondary cell wall development, making the young shoots softer and easier to chew and digest.
As shoots grow and age, the cells develop secondary cell walls that have a hard and tough structure.
Some plants (e.g. bracken) produce toxins that make their shoots inedible or less palatable.
Shoot types of woody plants
Many woody plants have distinct short shoots and long shoots. In some angiosperms, the short shoots, also called spur shoots or fruit spurs, produce the majority of flowers and fruit. A similar pattern occurs in some conifers and in Ginkgo, although the "short shoots" of some genera such as Picea are so small that they can be mistaken for part of the leaf that they have produced.
A related phenomenon is seasonal heterophylly, which involves visibly different leaves from spring growth and later lammas growth. Whereas spring growth mostly comes from buds formed the previous season, and often includes flowers, lammas growth often involves long shoots.
See also
Bud
Crown (botany)
Heteroblasty (botany), an abrupt change in the growth pattern of some plants as they mature
Lateral shoot
Phyllotaxis, the arrangement of leaves along a plant stem
Seedling
Sterigma, the "woody peg" below the leaf of some conifers
Thorn (botany), true thorns, as distinct from spines or prickles, are short shoots
Document 4:::
Crown sprouting is the ability of a plant to regenerate its shoot system after destruction (usually by fire) by activating dormant vegetative structures to produce regrowth from the root crown (the junction between the root and shoot portions of a plant). These dormant structures take the form of lignotubers or basal epicormic buds. Plant species that can accomplish crown sprouting are called crown resprouters (distinguishing them from stem or trunk resprouters) and, like them, are characteristic of fire-prone habitats such as chaparral.
In contrast to plant fire survival strategies that decrease the flammability of the plant, or by requiring heat to germinate, crown sprouting allows for the total destruction of the above ground growth. Crown sprouting plants typically have extensive root systems in which they store nutrients allowing them to survive during fires and sprout afterwards. Early researchers suggested that crown sprouting species might lack species genetic diversity; however, research on Gondwanan shrubland suggests that crown sprouting species have similar genetic diversity to seed sprouters. Some genera, such as Arctostaphylos and Ceanothus, have species that are both resprouters and not, both adapted to fire.
California Buckeye, Aesculus californica, is an example of a western United States tree which can regenerate from its root crown after a fire event, but can also regenerate by seed.
See also
Fire ecology
Lignotuber
Notes
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Fibrous root systems have many small branching roots called what?
A. fibrous roots
B. taproots
C. vines
D. tendrils
Answer:
|
|
ai2_arc-256
|
multiple_choice
|
Which energy conversion happens when a person shivers and the energy is transferred to make the muscles and joints move?
|
[
"kinetic energy to potential energy",
"heat energy to kinetic energy",
"potential energy to chemical energy",
"chemical energy to mechanical energy"
] |
D
|
Relavent Documents:
Document 0:::
Energy transformation, also known as energy conversion, is the process of changing energy from one form to another. In physics, energy is a quantity that provides the capacity to perform work or moving (e.g. lifting an object) or provides heat. In addition to being converted, according to the law of conservation of energy, energy is transferable to a different location or object, but it cannot be created or destroyed.
The energy in many of its forms may be used in natural processes, or to provide some service to society such as heating, refrigeration, lighting or performing mechanical work to operate machines. For example, to heat a home, the furnace burns fuel, whose chemical potential energy is converted into thermal energy, which is then transferred to the home's air to raise its temperature.
Limitations in the conversion of thermal energy
Conversions to thermal energy from other forms of energy may occur with 100% efficiency. Conversion among non-thermal forms of energy may occur with fairly high efficiency, though there is always some energy dissipated thermally due to friction and similar processes. Sometimes the efficiency is close to 100%, such as when potential energy is converted to kinetic energy as an object falls in a vacuum. This also applies to the opposite case; for example, an object in an elliptical orbit around another body converts its kinetic energy (speed) into gravitational potential energy (distance from the other object) as it moves away from its parent body. When it reaches the furthest point, it will reverse the process, accelerating and converting potential energy into kinetic. Since space is a near-vacuum, this process has close to 100% efficiency.
Thermal energy is unique because it in most cases (willow) cannot be converted to other forms of energy. Only a difference in the density of thermal/heat energy (temperature) can be used to perform work, and the efficiency of this conversion will be (much) less than 100%. This is because t
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Energy flow is the flow of energy through living things within an ecosystem. All living organisms can be organized into producers and consumers, and those producers and consumers can further be organized into a food chain. Each of the levels within the food chain is a trophic level. In order to more efficiently show the quantity of organisms at each trophic level, these food chains are then organized into trophic pyramids. The arrows in the food chain show that the energy flow is unidirectional, with the head of an arrow indicating the direction of energy flow; energy is lost as heat at each step along the way.
The unidirectional flow of energy and the successive loss of energy as it travels up the food web are patterns in energy flow that are governed by thermodynamics, which is the theory of energy exchange between systems. Trophic dynamics relates to thermodynamics because it deals with the transfer and transformation of energy (originating externally from the sun via solar radiation) to and among organisms.
Energetics and the carbon cycle
The first step in energetics is photosynthesis, wherein water and carbon dioxide from the air are taken in with energy from the sun, and are converted into oxygen and glucose. Cellular respiration is the reverse reaction, wherein oxygen and sugar are taken in and release energy as they are converted back into carbon dioxide and water. The carbon dioxide and water produced by respiration can be recycled back into plants.
Energy loss can be measured either by efficiency (how much energy makes it to the next level), or by biomass (how much living material exists at those levels at one point in time, measured by standing crop). Of all the net primary productivity at the producer trophic level, in general only 10% goes to the next level, the primary consumers, then only 10% of that 10% goes on to the next trophic level, and so on up the food pyramid. Ecological efficiency may be anywhere from 5% to 20% depending on how efficient
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Bioenergetics is a field in biochemistry and cell biology that concerns energy flow through living systems. This is an active area of biological research that includes the study of the transformation of energy in living organisms and the study of thousands of different cellular processes such as cellular respiration and the many other metabolic and enzymatic processes that lead to production and utilization of energy in forms such as adenosine triphosphate (ATP) molecules. That is, the goal of bioenergetics is to describe how living organisms acquire and transform energy in order to perform biological work. The study of metabolic pathways is thus essential to bioenergetics.
Overview
Bioenergetics is the part of biochemistry concerned with the energy involved in making and breaking of chemical bonds in the molecules found in biological organisms. It can also be defined as the study of energy relationships and energy transformations and transductions in living organisms. The ability to harness energy from a variety of metabolic pathways is a property of all living organisms. Growth, development, anabolism and catabolism are some of the central processes in the study of biological organisms, because the role of energy is fundamental to such biological processes. Life is dependent on energy transformations; living organisms survive because of exchange of energy between living tissues/ cells and the outside environment. Some organisms, such as autotrophs, can acquire energy from sunlight (through photosynthesis) without needing to consume nutrients and break them down. Other organisms, like heterotrophs, must intake nutrients from food to be able to sustain energy by breaking down chemical bonds in nutrients during metabolic processes such as glycolysis and the citric acid cycle. Importantly, as a direct consequence of the First Law of Thermodynamics, autotrophs and heterotrophs participate in a universal metabolic network—by eating autotrophs (plants), heterotrophs ha
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In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a stimulus.
Reflexes are found with varying levels of complexity in organisms with a nervous system. A reflex occurs via neural pathways in the nervous system called reflex arcs. A stimulus initiates a neural signal, which is carried to a synapse. The signal is then transferred across the synapse to a motor neuron, which evokes a target response. These neural signals do not always travel to the brain, so many reflexes are an automatic response to a stimulus that does not receive or need conscious thought.
Many reflexes are fine-tuned to increase organism survival and self-defense. This is observed in reflexes such as the startle reflex, which provides an automatic response to an unexpected stimulus, and the feline righting reflex, which reorients a cat's body when falling to ensure safe landing. The simplest type of reflex, a short-latency reflex, has a single synapse, or junction, in the signaling pathway. Long-latency reflexes produce nerve signals that are transduced across multiple synapses before generating the reflex response.
Types of human reflexes
Myotatic reflexes
The myotatic or muscle stretch reflexes (sometimes known as deep tendon reflexes) provide information on the integrity of the central nervous system and peripheral nervous system. This information can be detected using electromyography (EMG). Generally, decreased reflexes indicate a peripheral problem, and lively or exaggerated reflexes a central one. A stretch reflex is the contraction of a muscle in response to its lengthwise stretch.
Biceps reflex (C5, C6)
Brachioradialis reflex (C5, C6, C7)
Extensor digitorum reflex (C6, C7)
Triceps reflex (C6, C7, C8)
Patellar reflex or knee-jerk reflex (L2, L3, L4)
Ankle jerk reflex (Achilles reflex) (S1, S2)
While the reflexes above are stimulated mechanically, the term H-reflex refers to the analogous reflex stimulated
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The Haken-Kelso-Bunz (HKB) is a theoretical model of motor coordination originally formulated by Hermann Haken, J. A. Scott Kelso and H. Bunz. The model attempts to provide the framework for understanding coordinated behavior in living things. It accounts for experimental observations on human bimanual coordination that revealed fundamental features of self-organization: multistability, and phase transitions (switching). HKB is one of the most extensively tested quantitative models in the field of human movement behavior.
Phase Transitions ('Switches')
The HKB model differs from other motor coordination models with the addition of phase transitions (‘switches’). Kelso initially observed this phenomenon while conducting an experiment looking at subjects’ finger movements. Subjects oscillated their fingers rhythmically in the transverse plane (i.e., abduction-adduction) in one of two patterns, parallel or anti-parallel. In the parallel pattern, the finger muscles contract in an alternating fashion; in the anti-parallel pattern, the homologous finger muscles contract simultaneously. Kelso's study observed that when the subject begins in the parallel mode and increases the speed of movement, a spontaneous switch to symmetrical, anti-parallel movement occurs. This transition happens swiftly at a certain critical frequency. Surprisingly, after the switch has occurred and the movement rate decreases, Kelso's subjects remain in the symmetrical model (did not switch back). Kelso's study indicates that while humans are able to produce two patterns at low frequency values, only one—the symmetrical, anti-parallel mode remains stable as frequency is scaled beyond a critical value.
Prediction
The HKB model states that dynamic instability causes switching to occur. HKB measures stability in the following ways:
1. Critical slowing down. If a perturbation is applied to a system that takes it away from its stationary state, the time for a system to return to the stationary state
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Which energy conversion happens when a person shivers and the energy is transferred to make the muscles and joints move?
A. kinetic energy to potential energy
B. heat energy to kinetic energy
C. potential energy to chemical energy
D. chemical energy to mechanical energy
Answer:
|
|
ai2_arc-315
|
multiple_choice
|
Ptolemy was an ancient astronomer who thought Earth was the center of the universe. When he made observations that were inconsistent with this, he proposed a phenomenon called "epicycles" to explain the observations. How was Ptolemy's process similar to the modern scientific process?
|
[
"Ptolemy based his model partly on a belief system.",
"Observations inspired Ptolemy to modify his explanations.",
"Ptolemy tried to describe the universe instead of explaining it.",
"Experiments were the basis of Ptolemy's model of the universe."
] |
B
|
Relavent Documents:
Document 0:::
In mathematical psychology and education theory, a knowledge space is a combinatorial structure used to formulate mathematical models describing the progression of a human learner. Knowledge spaces were introduced in 1985 by Jean-Paul Doignon and Jean-Claude Falmagne, and remain in extensive use in the education theory. Modern applications include two computerized tutoring systems, ALEKS and the defunct RATH.
Formally, a knowledge space assumes that a domain of knowledge is a collection of concepts or skills, each of which must be eventually mastered. Not all concepts are interchangeable; some require other concepts as prerequisites. Conversely, competency at one skill may ease the acquisition of another through similarity. A knowledge space marks out which collections of skills are feasible: they can be learned without mastering any other skills. Under reasonable assumptions, the collection of feasible competencies forms the mathematical structure known as an antimatroid.
Researchers and educators usually explore the structure of a discipline's knowledge space as a latent class model.
Motivation
Knowledge Space Theory attempts to address shortcomings of standardized testing when used in educational psychometry. Common tests, such as the SAT and ACT, compress a student's knowledge into a very small range of ordinal ranks, in the process effacing the conceptual dependencies between questions. Consequently, the tests cannot distinguish between true understanding and guesses, nor can they identify a student's particular weaknesses, only the general proportion of skills mastered. The goal of knowledge space theory is to provide a language by which exams can communicate
What the student can do and
What the student is ready to learn.
Model structure
Knowledge Space Theory-based models presume that an educational subject can be modeled as a finite set of concepts, skills, or topics. Each feasible state of knowledge about is then a subset of ; the set of
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Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
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A pre-STEM program is a course of study at any two-year college that prepares a student to transfer to a four-year school to earn a bachelor's degree in a STEM field.
Overview
The concept of a pre-STEM program is being developed to address America's need for more college-trained professionals in science, technology, engineering, and mathematics (STEM). It is an innovation meant to fill a gap at community colleges that do not have 'major' degree paths that students identify with on their way to earning an Associates degree. Students must complete a considerable amount of STEM coursework before transferring from a two-year school to a four-year school and earn a baccalaureate degree in a STEM field. Schools with a pre-STEM program are able to identify those students and support them with STEM-specific academic and career advising, increasing the student's chances of going on to earn a STEM baccalaureate degree in a timely fashion.
With over 50% of America's college-bound students starting their college career at public or private two-year school, and with a very small proportion of students who start college at a two-year school matriculating to and earning STEM degrees from four-year schools, pre-STEM programs have great potential for broadening participation in baccalaureate STEM studies.
Example programs
The effectiveness of pre-STEM programs is being investigated by a consortium of schools in Missouri: Moberly Area Community College, St. Charles Community College, Metropolitan Community College, and Truman State University.
A larger group of schools met at the Belknap Springs Meetings in October 2009 to discuss the challenges and opportunities presented by STEM-focused partnerships between 2-year and 4-year schools. Each program represented a two-year school and a four-year school that were trying to increase the number of people who earn a baccalaureate degree in a STEM area through various means, some of which were pre-STEM programs. Other methods includes
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Science, technology, engineering, and mathematics (STEM) is an umbrella term used to group together the distinct but related technical disciplines of science, technology, engineering, and mathematics. The term is typically used in the context of education policy or curriculum choices in schools. It has implications for workforce development, national security concerns (as a shortage of STEM-educated citizens can reduce effectiveness in this area), and immigration policy, with regard to admitting foreign students and tech workers.
There is no universal agreement on which disciplines are included in STEM; in particular, whether or not the science in STEM includes social sciences, such as psychology, sociology, economics, and political science. In the United States, these are typically included by organizations such as the National Science Foundation (NSF), the Department of Labor's O*Net online database for job seekers, and the Department of Homeland Security. In the United Kingdom, the social sciences are categorized separately and are instead grouped with humanities and arts to form another counterpart acronym HASS (Humanities, Arts, and Social Sciences), rebranded in 2020 as SHAPE (Social Sciences, Humanities and the Arts for People and the Economy). Some sources also use HEAL (health, education, administration, and literacy) as the counterpart of STEM.
Terminology
History
Previously referred to as SMET by the NSF, in the early 1990s the acronym STEM was used by a variety of educators, including Charles E. Vela, the founder and director of the Center for the Advancement of Hispanics in Science and Engineering Education (CAHSEE). Moreover, the CAHSEE started a summer program for talented under-represented students in the Washington, D.C., area called the STEM Institute. Based on the program's recognized success and his expertise in STEM education, Charles Vela was asked to serve on numerous NSF and Congressional panels in science, mathematics, and engineering edu
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The Vicarious Hypothesis, or hypothesis vicaria, was a planetary hypothesis proposed by Johannes Kepler to describe the motion of Mars. The hypothesis adopted the circular orbit and equant of Ptolemy's planetary model as well as the heliocentrism of the Copernican model. Calculations using the Vicarious Hypothesis did not support a circular orbit for Mars, leading Kepler to propose elliptical orbits as one of three laws of planetary motion in Astronomia Nova.
History
In 1600, Johannes Kepler met and began working with Tycho Brahe at Benátky, a town north of Prague where Brahe's new observatory was being built. Brahe assigned Kepler the task of modeling the motion of Mars using only data that Brahe had collected himself. Upon the death of Brahe in 1601, all of Brahe's data was willed to Kepler. Brahe's observational data was among the most accurate of his time, which Kepler used in the construction of the Vicarious Hypothesis.
Predecessors
Ptolemy
Claudius Ptolemy's planetary model consisted of a stationary earth surrounded by fixed circles, called deferents, which carried smaller, rotating circles called epicycles. Planets rotated on the epicycles as the epicycles traveled along the deferent. Ptolemy shifted the Earth away from the center of the deferent and introduced another point, the equant, equidistant to the deferent's center on the opposite side of the Earth.
The Vicarious Hypothesis uses a circular orbit for Mars and reintroduces a form of the equant to describe the motion of Mars with constant angular speed.
Copernicus
Nicolaus Copernicus broke from the geocentric model of Ptolemy by placing the Sun at the center of his planetary model. However, Copernicus retained circular orbits for the planets and added an orbit for the Earth, insisting that the Earth revolved around the Sun. The Sun was positioned off-center of the orbits but was still contained within all orbits.
Kepler adopted Copernican heliocentrism in the construction of the Vicarious Hyp
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Ptolemy was an ancient astronomer who thought Earth was the center of the universe. When he made observations that were inconsistent with this, he proposed a phenomenon called "epicycles" to explain the observations. How was Ptolemy's process similar to the modern scientific process?
A. Ptolemy based his model partly on a belief system.
B. Observations inspired Ptolemy to modify his explanations.
C. Ptolemy tried to describe the universe instead of explaining it.
D. Experiments were the basis of Ptolemy's model of the universe.
Answer:
|
|
sciq-8289
|
multiple_choice
|
Pathogens infect many animals and are agents of what?
|
[
"change",
"drought",
"mutation",
"disease"
] |
D
|
Relavent Documents:
Document 0:::
In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ.
The term pathogen came into use in the 1880s. Typically, the term pathogen is used to describe an infectious microorganism or agent, such as a virus, bacterium, protozoan, prion, viroid, or fungus. Small animals, such as helminths and insects, can also cause or transmit disease. However, these animals are usually referred to as parasites rather than pathogens. The scientific study of microscopic organisms, including microscopic pathogenic organisms, is called microbiology, while parasitology refers to the scientific study of parasites and the organisms that host them.
There are several pathways through which pathogens can invade a host. The principal pathways have different episodic time frames, but soil has the longest or most persistent potential for harboring a pathogen.
Diseases in humans that are caused by infectious agents are known as pathogenic diseases. Not all diseases are caused by pathogens, such as black lung from exposure to the pollutant coal dust, genetic disorders like sickle cell disease, and autoimmune diseases like lupus.
Pathogenicity
Pathogenicity is the potential disease-causing capacity of pathogens, involving a combination of infectivity (pathogen's ability to infect hosts) and virulence (severity of host disease). Koch's postulates are used to establish causal relationships between microbial pathogens and diseases. Whereas meningitis can be caused by a variety of bacterial, viral, fungal, and parasitic pathogens, cholera is only caused by some strains of Vibrio cholerae. Additionally, some pathogens may only cause disease in hosts with an immunodeficiency. These opportunistic infections often involve hospital-acquired infections among patients already combating another condition.
Infectivity involves path
Document 1:::
MicrobeLibrary is a permanent collection of over 1400 original peer-reviewed resources for teaching undergraduate microbiology. It is provided by the American Society for Microbiology, Washington DC, United States.
Contents include curriculum activities; images and animations; reviews of books, websites and other resources; and articles from Focus on Microbiology Education, Microbiology Education and Microbe. Around 40% of the materials are free to educators and students, the remainder require a subscription. the service is suspended with the message to:
"Please check back with us in 2017".
External links
MicrobeLibrary
Microbiology
Document 2:::
Biosafety level 4 (BSL-4) organisms are dangerous or exotic agents which pose high risk of life-threatening disease, aerosol-transmitted lab infections, or related agents with unknown risk of transmission.
US federal biocontainment regulations
Biosafety level 4 laboratories are designed for diagnostic work and research on easily respiratory-acquired viruses which can often cause severe and/or fatal disease. What follows is a list of select agents that have specific biocontainment requirements according to US federal law. Organisms include those harmful to human health, or to animal health. The Plant Protection and Quarantine programs (PPQ) of the Animal and Plant Health Inspection Service (APHIS) are listed in 7 CFR Part 331. The Department of Health and Human Services (HHS) lists are located at 42 CFR Part 73.3 and 42 CFR Part 73.4. The USDA animal safety list is located at 9 CFR Subchapter B.
Not all select agents require BSL-4 handling, namely select bacteria and toxins, but most select agent viruses do (with the notable exception of SARS-CoV-1 which can be handled in BSL3). Many non-select agent viruses are often handled in BSL-4 according to facility SOPs or when dealing with new viruses closely related to viruses that require BSL-4. For instance, Andes orthohantavirus and MERS-CoV are both non-select agents that are often handled in BSL-4 because they cause severe and fatal disease in humans. Newly characterized viruses closely related to select agents and/or BSL-4 viruses (for example newly discovered henipaviruses or ebolaviruses) are typically handled in BSL-4 even if they aren't yet known to be readily transmissible or cause severe disease.
International BSL-4 regulations
Globally, there are no official agreements on what agents must be handled in BSL-4. However, select agents and toxins originating or ending in US BSL-4 labs must adhere to US select agent laws.
Select agents
HHS human threats: select agents and toxins
Crimean-Congo hemorrhagic fe
Document 3:::
When considering pathogens, host adaptation can have varying descriptions. For example, in the case of Salmonella, host adaptation is used to describe the "ability of a pathogen to circulate and cause disease in a particular host population." Another usage of host adaptation, still considering the case of Salmonella, refers to the evolution of a pathogen such that it can infect, cause disease, and circulate in another host species.
Description
While there might be pathogens that can infect other hosts and cause disease, the inability to pervade, or spread, throughout the infected host species indicates that the pathogen is not adapted to that host species. In this case, the ability or lack thereof of a pathogen to adapt to its host environment is an indicator of the pathogen's fitness or virulence. If a pathogen has high fitness in the host environment, or is virulent, it will be able to grow and spread quickly within its host. Conversely, if the pathogen is not well adapted to its host environment, then it will not spread or infect the way a well adapted pathogen would.
Pathogens like Salmonella, which is a food borne pathogen, are able to adapt to the host environment and maintain virulence via several pathways. In a paper by Baumler et al. 1998, characters of Salmonella, such as its ability to cause intestinal infection were attributed to virulence factors like its ability to invade intestinal epithelial cells, induce neutrophil recruitment and interfere with the secretion of intestinal fluid. Phylogenetic analysis also revealed that many strains or lineages of Salmonella exist, which is advantageous for the pathogen because its genetic diversity can acts as fodder for natural selection to tinder with. For instance, if a particular Salmonella strain is more fit in the host stomach environment, compared to other Salmonella strains, then the former will be positively selected for and increase in prevalence. Eventually this strain will colonize and infect the st
Document 4:::
A microbiologist (from Greek ) is a scientist who studies microscopic life forms and processes. This includes study of the growth, interactions and characteristics of microscopic organisms such as bacteria, algae, fungi, and some types of parasites and their vectors. Most microbiologists work in offices and/or research facilities, both in private biotechnology companies and in academia. Most microbiologists specialize in a given topic within microbiology such as bacteriology, parasitology, virology, or immunology.
Duties
Microbiologists generally work in some way to increase scientific knowledge or to utilise that knowledge in a way that improves outcomes in medicine or some industry. For many microbiologists, this work includes planning and conducting experimental research projects in some kind of laboratory setting. Others may have a more administrative role, supervising scientists and evaluating their results. Microbiologists working in the medical field, such as clinical microbiologists, may see patients or patient samples and do various tests to detect disease-causing organisms.
For microbiologists working in academia, duties include performing research in an academic laboratory, writing grant proposals to fund research, as well as some amount of teaching and designing courses. Microbiologists in industry roles may have similar duties except research is performed in industrial labs in order to develop or improve commercial products and processes. Industry jobs may also not include some degree of sales and marketing work, as well as regulatory compliance duties. Microbiologists working in government may have a variety of duties, including laboratory research, writing and advising, developing and reviewing regulatory processes, and overseeing grants offered to outside institutions. Some microbiologists work in the field of patent law, either with national patent offices or private law practices. Her duties include research and navigation of intellectual proper
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Pathogens infect many animals and are agents of what?
A. change
B. drought
C. mutation
D. disease
Answer:
|
|
sciq-3194
|
multiple_choice
|
What living things have cell walls containing cellulose and plastids such as chloroplasts?
|
[
"reptiles",
"plants",
"mammals",
"animals"
] |
B
|
Relavent Documents:
Document 0:::
Cellular components are the complex biomolecules and structures of which cells, and thus living organisms, are composed. Cells are the structural and functional units of life. The smallest organisms are single cells, while the largest organisms are assemblages of trillions of cells. DNA, double stranded macromolecule that carries the hereditary information of the cell and found in all living cells; each cell carries chromosome(s) having a distinctive DNA sequence.
Examples include macromolecules such as proteins and nucleic acids, biomolecular complexes such as a ribosome, and structures such as membranes, and organelles. While the majority of cellular components are located within the cell itself, some may exist in extracellular areas of an organism.
Cellular components may also be called biological matter or biological material. Most biological matter has the characteristics of soft matter, being governed by relatively small energies. All known life is made of biological matter. To be differentiated from other theoretical or fictional life forms, such life may be called carbon-based, cellular, organic, biological, or even simply living – as some definitions of life exclude hypothetical types of biochemistry.
See also
Cell (biology)
Cell biology
Biomolecule
Organelle
Tissue (biology)
External links
https://web.archive.org/web/20130918033010/http://bioserv.fiu.edu/~walterm/FallSpring/review1_fall05_chap_cell3.htm
Document 1:::
The cell is the basic structural and functional unit of all forms of life. Every cell consists of cytoplasm enclosed within a membrane, and contains many macromolecules such as proteins, DNA and RNA, as well as many small molecules of nutrients and metabolites. The term comes from the Latin word meaning 'small room'.
Cells can acquire specified function and carry out various tasks within the cell such as replication, DNA repair, protein synthesis, and motility. Cells are capable of specialization and mobility within the cell.
Most plant and animal cells are only visible under a light microscope, with dimensions between 1 and 100 micrometres. Electron microscopy gives a much higher resolution showing greatly detailed cell structure. Organisms can be classified as unicellular (consisting of a single cell such as bacteria) or multicellular (including plants and animals). Most unicellular organisms are classed as microorganisms.
The study of cells and how they work has led to many other studies in related areas of biology, including: discovery of DNA, cancer systems biology, aging and developmental biology.
Cell biology is the study of cells, which were discovered by Robert Hooke in 1665, who named them for their resemblance to cells inhabited by Christian monks in a monastery. Cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, and that all cells come from pre-existing cells. Cells emerged on Earth about 4 billion years ago.
Discovery
With continual improvements made to microscopes over time, magnification technology became advanced enough to discover cells. This discovery is largely attributed to Robert Hooke, and began the scientific study of cells, known as cell biology. When observing a piece of cork under the scope, he was able to see pores. This was shocking at the time as i
Document 2:::
In biology, cell theory is a scientific theory first formulated in the mid-nineteenth century, that organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells. Cells are the basic unit of structure in all organisms and also the basic unit of reproduction.
The theory was once universally accepted, but now some biologists consider non-cellular entities such as viruses living organisms, and thus disagree with the first tenet. As of 2021: "expert opinion remains divided roughly a third each between yes, no and don’t know". As there is no universally accepted definition of life, discussion still continues.
History
With continual improvements made to microscopes over time, magnification technology became advanced enough to discover cells. This discovery is largely attributed to Robert Hooke, and began the scientific study of cells, known as cell biology. When observing a piece of cork under the scope, he was able to see pores. This was shocking at the time as it was believed no one else had seen these. To further support his theory, Matthias Schleiden and Theodor Schwann both also studied cells of both animal and plants. What they discovered were significant differences between the two types of cells. This put forth the idea that cells were not only fundamental to plants, but animals as well.
Microscopes
The discovery of the cell was made possible through the invention of the microscope. In the first century BC, Romans were able to make glass. They discovered that objects appeared to be larger under the glass. The expanded use of lenses in eyeglasses in the 13th century probably led to wider spread use of simple microscopes (magnifying glasses) with limited magnification. Compound microscopes, which combine an objective lens with an eyepiece to view a real image achieving much higher magnification, first appeared in Europe around 1620. In 1665, Robert Hooke used a microscope
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In biology, the extracellular matrix (ECM), is a network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and biochemical support to surrounding cells. Because multicellularity evolved independently in different multicellular lineages, the composition of ECM varies between multicellular structures; however, cell adhesion, cell-to-cell communication and differentiation are common functions of the ECM.
The animal extracellular matrix includes the interstitial matrix and the basement membrane. Interstitial matrix is present between various animal cells (i.e., in the intercellular spaces). Gels of polysaccharides and fibrous proteins fill the interstitial space and act as a compression buffer against the stress placed on the ECM. Basement membranes are sheet-like depositions of ECM on which various epithelial cells rest. Each type of connective tissue in animals has a type of ECM: collagen fibers and bone mineral comprise the ECM of bone tissue; reticular fibers and ground substance comprise the ECM of loose connective tissue; and blood plasma is the ECM of blood.
The plant ECM includes cell wall components, like cellulose, in addition to more complex signaling molecules. Some single-celled organisms adopt multicellular biofilms in which the cells are embedded in an ECM composed primarily of extracellular polymeric substances (EPS).
Structure
Components of the ECM are produced intracellularly by resident cells and secreted into the ECM via exocytosis. Once secreted, they then aggregate with the existing matrix. The ECM is composed of an interlocking mesh of fibrous proteins and glycosaminoglycans (GAGs).
Proteoglycans
Glycosaminoglycans (GAGs) are carbohydrate polymers and mostly attached to extracellular matrix proteins to form proteoglycans (hyaluronic acid is a notable exception; see below). Proteoglycans have a net negative charge that attracts positively charged sod
Document 4:::
Ergastic substances are non-protoplasmic materials found in cells. The living protoplasm of a cell is sometimes called the bioplasm and distinct from the ergastic substances of the cell. The latter are usually organic or inorganic substances that are products of metabolism, and include crystals, oil drops, gums, tannins, resins and other compounds that can aid the organism in defense, maintenance of cellular structure, or just substance storage. Ergastic substances may appear in the protoplasm, in vacuoles, or in the cell wall.
Carbohydrates
Reserve carbohydrate of plants are the derivatives of the end products of photosynthesis. Cellulose and starch are the main ergastic substances of plant cells. Cellulose is the chief component of the cell wall, and starch occurs as a reserve material in the protoplasm.
Starch, as starch grains, arise almost exclusively in plastids, especially leucoplasts and amyloplasts.
Proteins
Although proteins are the main component of living protoplasm, proteins can occur as inactive, ergastic bodies—in an amorphous or crystalline (or crystalloid) form. A well-known amorphous ergastic protein is gluten.
Fats and oils
Fats (lipids) and oils are widely distributed in plant tissues. Substances related to fats—waxes, suberin, and cutin—occur as protective layers in or on the cell wall.
Crystals
Animals eliminate excess inorganic materials; plants mostly deposit such material in their tissues. Such mineral matter is mostly salts of calcium and anhydrides of silica.
Raphides are a type of elongated crystalline form of calcium oxalate aggregated in bundles within a plant cell. Because of the needle-like form, large numbers in the tissue of, say, a leaf can render the leaf unpalatable to herbivores (see Dieffenbachia and taro).
Druse
Cystolith
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What living things have cell walls containing cellulose and plastids such as chloroplasts?
A. reptiles
B. plants
C. mammals
D. animals
Answer:
|
|
sciq-8294
|
multiple_choice
|
People with which skin type run a greater risk of vitamin d deficiency?
|
[
"brighter skin",
"lighter skin",
"darker skin",
"weaker skin"
] |
C
|
Relavent Documents:
Document 0:::
The SAT Subject Test in Biology was the name of a one-hour multiple choice test given on biology by the College Board. A student chose whether to take the test depending upon college entrance requirements for the schools in which the student is planning to apply. Until 1994, the SAT Subject Tests were known as Achievement Tests; and from 1995 until January 2005, they were known as SAT IIs. Of all SAT subject tests, the Biology E/M test was the only SAT II that allowed the test taker a choice between the ecological or molecular tests. A set of 60 questions was taken by all test takers for Biology and a choice of 20 questions was allowed between either the E or M tests. This test was graded on a scale between 200 and 800. The average for Molecular is 630 while Ecological is 591.
On January 19 2021, the College Board discontinued all SAT Subject tests, including the SAT Subject Test in Biology E/M. This was effective immediately in the United States, and the tests were to be phased out by the following summer for international students. This was done as a response to changes in college admissions due to the impact of the COVID-19 pandemic on education.
Format
This test had 80 multiple-choice questions that were to be answered in one hour. All questions had five answer choices. Students received one point for each correct answer, lost ¼ of a point for each incorrect answer, and received 0 points for questions left blank. The student's score was based entirely on his or her performance in answering the multiple-choice questions.
The questions covered a broad range of topics in general biology. There were more specific questions related respectively on ecological concepts (such as population studies and general Ecology) on the E test and molecular concepts such as DNA structure, translation, and biochemistry on the M test.
Preparation
The College Board suggested a year-long course in biology at the college preparatory level, as well as a one-year course in algebra, a
Document 1:::
GRE Subject Biochemistry, Cell and Molecular Biology was a standardized exam provided by ETS (Educational Testing Service) that was discontinued in December 2016. It is a paper-based exam and there are no computer-based versions of it. ETS places this exam three times per year: once in April, once in October and once in November. Some graduate programs in the United States recommend taking this exam, while others require this exam score as a part of the application to their graduate programs. ETS sends a bulletin with a sample practice test to each candidate after registration for the exam. There are 180 questions within the biochemistry subject test.
Scores are scaled and then reported as a number between 200 and 990; however, in recent versions of the test, the maximum and minimum reported scores have been 760 (corresponding to the 99 percentile) and 320 (1 percentile) respectively. The mean score for all test takers from July, 2009, to July, 2012, was 526 with a standard deviation of 95.
After learning that test content from editions of the GRE® Biochemistry, Cell and Molecular Biology (BCM) Test has been compromised in Israel, ETS made the decision not to administer this test worldwide in 2016–17.
Content specification
Since many students who apply to graduate programs in biochemistry do so during the first half of their fourth year, the scope of most questions is largely that of the first three years of a standard American undergraduate biochemistry curriculum. A sampling of test item content is given below:
Biochemistry (36%)
A Chemical and Physical Foundations
Thermodynamics and kinetics
Redox states
Water, pH, acid-base reactions and buffers
Solutions and equilibria
Solute-solvent interactions
Chemical interactions and bonding
Chemical reaction mechanisms
B Structural Biology: Structure, Assembly, Organization and Dynamics
Small molecules
Macromolecules (e.g., nucleic acids, polysaccharides, proteins and complex lipids)
Supramolecular complexes (e.g.
Document 2:::
Single Best Answer (SBA or One Best Answer) is a written examination form of multiple choice questions used extensively in medical education.
Structure
A single question is posed with typically five alternate answers, from which the candidate must choose the best answer. This method avoids the problems of past examinations of a similar form described as Single Correct Answer. The older form can produce confusion where more than one of the possible answers has some validity. The newer form makes it explicit that more than one answer may have elements that are correct, but that one answer will be superior.
Prior to the widespread introduction of SBAs into medical education, the typical form of examination was true-false multiple choice questions. But during the 2000s, educators found that SBAs would be superior.
Document 3:::
Vitamin D and Omega-3 Trial (VITAL) was a clinical trial designed to investigate the use of daily dietary supplements of vitamin D and fish oil.
The sponsor of the study was Brigham and Women's Hospital, collaborating with The National Cancer Institute, National Heart, Lung, and Blood Institute, Office of Dietary Supplements, National Institute of Neurological Disorders and Stroke, National Center for Complementary and Integrative Health, Pharmavite LLC, Pronova BioPharma and BASF.
The studied aimed to enroll 20,000 participants (women 55 or over, men 50 or over) who were randomized into one of four groups:
daily vitamin D (2000 IU) and fish oil (1 g);
daily vitamin D and fish-oil placebo;
daily vitamin-D placebo and fish oil;
daily vitamin-D placebo and fish-oil placebo.
Participants answered annual questionnaires to determine effects the risks of developing cancer, heart disease, stroke, osteoporosis, diabetes, memory loss and depression.
The outcome of this study was:
"The results of this trial indicate that supplementation with either n–3 fatty acid at a dose of 1 g/day or vitamin D3 at a dose of 2000 IU/day was not effective for primary prevention of CV or cancer events among healthy middle-aged men and women over 5 years of follow-up. There was also no difference in progression/development of CKD among patients with type 2 diabetes. This is one of the largest trials on this topic. The finding of a lower MI risk with n–3 fatty acid is hypothesis generating and deserves further study. The authors also noted some interaction with baseline fish consumption, with greater CV benefit observed among participants who had low fish intake at baseline."
Document 4:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
People with which skin type run a greater risk of vitamin d deficiency?
A. brighter skin
B. lighter skin
C. darker skin
D. weaker skin
Answer:
|
|
sciq-2462
|
multiple_choice
|
In humans, pharyngeal slits later develop into what?
|
[
"outer ear",
"long ear",
"middle ear",
"inner ear"
] |
C
|
Relavent Documents:
Document 0:::
The pharyngeal apparatus is an embryological structure.
It consists of:
pharyngeal grooves (from ectoderm)
pharyngeal arches (from mesoderm)
pharyngeal pouches (from endoderm)
and related membranes.
Document 1:::
The lateral half of the great wing of the sphenoid bone articulates, by means of a synchondrosis, with the petrous part of the temporal bone. Between these two bones on the under surface of the skull, is a furrow, the 'sulcus of auditory tubule, for the lodgement of the cartilaginous part of the auditory tube.
Document 2:::
The round window is one of the two openings from the middle ear into the inner ear. It is sealed by the secondary tympanic membrane (round window membrane), which vibrates with opposite phase to vibrations entering the inner ear through the oval window. It allows fluid in the cochlea to move, which in turn ensures that hair cells of the basilar membrane will be stimulated and that audition will occur.
Structure
The round window is situated below (inferior to) and a little behind (posterior to) the oval window, from which it is separated by a rounded elevation, the promontory.
It is located at the bottom of a funnel-shaped depression (the round window niche) and, in the macerated bone, opens into the cochlea of the internal ear; in the fresh state it is closed by a membrane, the secondary tympanic membrane (, or ) or round window membrane, which is a complex saddle point shape. The visible central portion is concave (curved inwards) toward the tympanic cavity and convex (curved outwards) toward the cochlea; but towards the edges, where it is hidden in the round window niche, it curves the other way.
This membrane consists of three layers:
an external, or mucous, derived from the mucous lining of the tympanic cavity;
an internal, from the lining membrane of the cochlea;
and an intermediate, or fibrous layer.
The membrane vibrates with opposite phase to vibrations entering the cochlea through the oval window as the fluid in the cochlea is displaced when pressed by the stapes at the oval window. This ensures that hair cells of the basilar membrane will be stimulated and that audition will occur.
Both the oval and round windows are about the same size, approximately . The entrance to the round window niche is often much smaller than this.
Function
The stapes bone transmits movement to the oval window. As the stapes footplate moves into the oval window, the round window membrane moves out, and this allows movement of the fluid within the cochlea, leading to mo
Document 3:::
The tympanic part of the temporal bone is a curved plate of bone lying below the squamous part of the temporal bone, in front of the mastoid process, and surrounding the external part of the ear canal.
It originates as a separate bone (tympanic bone), which in some mammals stays separate through life.
Evolutionarily, a portion of it is derived from the angular bone of the reptilian lower jaw.
Surfaces
Its postero-superior surface is concave, and forms the anterior wall, the floor, and part of the posterior wall of the bony ear canal.
Medially, it presents a narrow furrow, the tympanic sulcus, for the attachment of the tympanic membrane.
Its antero-inferior surface is quadrilateral and slightly concave; it constitutes the posterior boundary of the mandibular fossa, and is in contact with the retromandibular part of the parotid gland.
Borders
Its lateral border is free and rough, and gives attachment to the cartilaginous part of the ear canal. Internally, the tympanic part is fused with the petrous portion, and appears in the retreating angle between it and the squama, where it lies below and lateral to the orifice of the auditory tube. Posteriorly, it blends with the squama and mastoid part, and forms the anterior boundary of the tympanomastoid fissure.
Its upper border fuses laterally with the back of the postglenoid process, while medially it bounds the petrotympanic fissure.
The medial part of the lower border is thin and sharp; its lateral part splits to enclose the root of the styloid process, and is therefore named the vaginal process.
Ear canal
The central portion of the tympanic part is thin, as it gives rise to the bony inner two-thirds of the ear canal, and in 5 - 20% of skulls the lower surface is perforated by a hole, the foramen of Huschke that opens onto the temporomandibular joint due to incomplete fusion of the anterior and posterior prominences during development.
The bony portion of the ear canal is nearly 2 cm long and is directed inwa
Document 4:::
Pharyngeal slits are filter-feeding organs found among deuterostomes. Pharyngeal slits are repeated openings that appear along the pharynx caudal to the mouth. With this position, they allow for the movement of water in the mouth and out the pharyngeal slits. It is postulated that this is how pharyngeal slits first assisted in filter-feeding, and later, with the addition of gills along their walls, aided in respiration of aquatic chordates. These repeated segments are controlled by similar developmental mechanisms. Some hemichordate species can have as many as 200 gill slits. Pharyngeal clefts resembling gill slits are transiently present during the embryonic stages of tetrapod development. The presence of pharyngeal arches and clefts in the neck of the developing human embryo famously led Ernst Haeckel to postulate that "ontogeny recapitulates phylogeny"; this hypothesis, while false, contains elements of truth, as explored by Stephen Jay Gould in Ontogeny and Phylogeny. However, it is now accepted that it is the vertebrate pharyngeal pouches and not the neck slits that are homologous to the pharyngeal slits of invertebrate chordates. Pharyngeal arches, pouches, and clefts are, at some stage of life, found in all chordates. One theory of their origin is the fusion of nephridia which opened both on the outside and the gut, creating openings between the gut and the environment.
Pharyngeal arches in Vertebrates
In vertebrates, the pharyngeal arches are derived from all three germ layers. Neural crest cells enter these arches where they contribute to craniofacial features such as bone and cartilage. However, the existence of pharyngeal structures before neural crest cells evolved is indicated by the existence of neural crest-independent mechanisms of pharyngeal arch development. The first, most anterior pharyngeal arch gives rise to the oral jaw. The second arch becomes the hyoid and jaw support. In fish, the other posterior arches contribute to the brachial ske
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
In humans, pharyngeal slits later develop into what?
A. outer ear
B. long ear
C. middle ear
D. inner ear
Answer:
|
|
sciq-11647
|
multiple_choice
|
Since warmer molecules have more energy, they are more what?
|
[
"active",
"inactive",
"dense",
"abundant"
] |
A
|
Relavent Documents:
Document 0:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 1:::
GRE Subject Biochemistry, Cell and Molecular Biology was a standardized exam provided by ETS (Educational Testing Service) that was discontinued in December 2016. It is a paper-based exam and there are no computer-based versions of it. ETS places this exam three times per year: once in April, once in October and once in November. Some graduate programs in the United States recommend taking this exam, while others require this exam score as a part of the application to their graduate programs. ETS sends a bulletin with a sample practice test to each candidate after registration for the exam. There are 180 questions within the biochemistry subject test.
Scores are scaled and then reported as a number between 200 and 990; however, in recent versions of the test, the maximum and minimum reported scores have been 760 (corresponding to the 99 percentile) and 320 (1 percentile) respectively. The mean score for all test takers from July, 2009, to July, 2012, was 526 with a standard deviation of 95.
After learning that test content from editions of the GRE® Biochemistry, Cell and Molecular Biology (BCM) Test has been compromised in Israel, ETS made the decision not to administer this test worldwide in 2016–17.
Content specification
Since many students who apply to graduate programs in biochemistry do so during the first half of their fourth year, the scope of most questions is largely that of the first three years of a standard American undergraduate biochemistry curriculum. A sampling of test item content is given below:
Biochemistry (36%)
A Chemical and Physical Foundations
Thermodynamics and kinetics
Redox states
Water, pH, acid-base reactions and buffers
Solutions and equilibria
Solute-solvent interactions
Chemical interactions and bonding
Chemical reaction mechanisms
B Structural Biology: Structure, Assembly, Organization and Dynamics
Small molecules
Macromolecules (e.g., nucleic acids, polysaccharides, proteins and complex lipids)
Supramolecular complexes (e.g.
Document 2:::
A pre-STEM program is a course of study at any two-year college that prepares a student to transfer to a four-year school to earn a bachelor's degree in a STEM field.
Overview
The concept of a pre-STEM program is being developed to address America's need for more college-trained professionals in science, technology, engineering, and mathematics (STEM). It is an innovation meant to fill a gap at community colleges that do not have 'major' degree paths that students identify with on their way to earning an Associates degree. Students must complete a considerable amount of STEM coursework before transferring from a two-year school to a four-year school and earn a baccalaureate degree in a STEM field. Schools with a pre-STEM program are able to identify those students and support them with STEM-specific academic and career advising, increasing the student's chances of going on to earn a STEM baccalaureate degree in a timely fashion.
With over 50% of America's college-bound students starting their college career at public or private two-year school, and with a very small proportion of students who start college at a two-year school matriculating to and earning STEM degrees from four-year schools, pre-STEM programs have great potential for broadening participation in baccalaureate STEM studies.
Example programs
The effectiveness of pre-STEM programs is being investigated by a consortium of schools in Missouri: Moberly Area Community College, St. Charles Community College, Metropolitan Community College, and Truman State University.
A larger group of schools met at the Belknap Springs Meetings in October 2009 to discuss the challenges and opportunities presented by STEM-focused partnerships between 2-year and 4-year schools. Each program represented a two-year school and a four-year school that were trying to increase the number of people who earn a baccalaureate degree in a STEM area through various means, some of which were pre-STEM programs. Other methods includes
Document 3:::
Female education in STEM refers to child and adult female representation in the educational fields of science, technology, engineering, and mathematics (STEM). In 2017, 33% of students in STEM fields were women.
The organization UNESCO has stated that this gender disparity is due to discrimination, biases, social norms and expectations that influence the quality of education women receive and the subjects they study. UNESCO also believes that having more women in STEM fields is desirable because it would help bring about sustainable development.
Current status of girls and women in STEM education
Overall trends in STEM education
Gender differences in STEM education participation are already visible in early childhood care and education in science- and math-related play, and become more pronounced at higher levels of education. Girls appear to lose interest in STEM subjects with age, particularly between early and late adolescence. This decreased interest affects participation in advanced studies at the secondary level and in higher education. Female students represent 35% of all students enrolled in STEM-related fields of study at this level globally. Differences are also observed by disciplines, with female enrollment lowest in engineering, manufacturing and construction, natural science, mathematics and statistics and ICT fields. Significant regional and country differences in female representation in STEM studies can be observed, though, suggesting the presence of contextual factors affecting girls’ and women's engagement in these fields. Women leave STEM disciplines in disproportionate numbers during their higher education studies, in their transition to the world of work and even in their career cycle.
Learning achievement in STEM education
Data on gender differences in learning achievement present a complex picture, depending on what is measured (subject, knowledge acquisition against knowledge application), the level of education/age of students, and
Document 4:::
Shpolskii systems are low-temperature host–guest systems – they are typically rapidly frozen solutions of polycyclic aromatic hydrocarbons in suitable low molecular weight normal alkanes. The emission and absorption spectra of lowest energy electronic transitions in the Shpolskii systems exhibit narrow lines instead of the inhomogeneously broadened features normally associated with spectra of chromophores in liquids and amorphous solids. The effect was first described by Eduard Shpolskii in the 1950s and 1960's in the journals Transactions of the U.S.S.R. Academy of Sciences and Soviet Physics Uspekhi.
Subsequent detailed studies of concentration and speed of cooling behavior of Shpolskii systems by L. A. Nakhimovsky and coauthors led to a hypothesis that these systems are metastable segregational solid solutions formed when one or more chromophores replace two or more molecules in the host crystalline lattice. The solid state quasi-equilibrium solubility in most Shpolskii systems is very low. When the Shpolskii effect is manifested, the solid state solubility increases two to three orders of magnitude. Isothermic annealing of the supersaturated rapidly frozen solutions of dibenzofuran in heptane was performed, and it was shown that the return of the metastable system to equilibrium in time reasonable for laboratory observation required the annealing temperature to be close to the melting temperature of the metastable frozen solution. Thus the Shpolskii systems are an example of a persistent metastable state.
A good match between the chromophore and the host lattice leads to a uniform environment for all the chromophores and hence greatly reduces the inhomogeneous broadening of the electronic transition's pure electronic and vibronic lines. In addition to the weak inhomogeneous broadening of the transitions, the quasi-lines observed at very low temperatures are phonon-less transitions. Since phonons originate in the lattice, an additional requirement is weak ch
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Since warmer molecules have more energy, they are more what?
A. active
B. inactive
C. dense
D. abundant
Answer:
|
|
sciq-11642
|
multiple_choice
|
Because their cells are arranged in bundles, the appearance of skeletal and cardiac muscles is described as what?
|
[
"quadrant",
"incised",
"striated",
"cylindrical"
] |
C
|
Relavent Documents:
Document 0:::
Outline
h1.00: Cytology
h2.00: General histology
H2.00.01.0.00001: Stem cells
H2.00.02.0.00001: Epithelial tissue
H2.00.02.0.01001: Epithelial cell
H2.00.02.0.02001: Surface epithelium
H2.00.02.0.03001: Glandular epithelium
H2.00.03.0.00001: Connective and supportive tissues
H2.00.03.0.01001: Connective tissue cells
H2.00.03.0.02001: Extracellular matrix
H2.00.03.0.03001: Fibres of connective tissues
H2.00.03.1.00001: Connective tissue proper
H2.00.03.1.01001: Ligaments
H2.00.03.2.00001: Mucoid connective tissue; Gelatinous connective tissue
H2.00.03.3.00001: Reticular tissue
H2.00.03.4.00001: Adipose tissue
H2.00.03.5.00001: Cartilage tissue
H2.00.03.6.00001: Chondroid tissue
H2.00.03.7.00001: Bone tissue; Osseous tissue
H2.00.04.0.00001: Haemotolymphoid complex
H2.00.04.1.00001: Blood cells
H2.00.04.1.01001: Erythrocyte; Red blood cell
H2.00.04.1.02001: Leucocyte; White blood cell
H2.00.04.1.03001: Platelet; Thrombocyte
H2.00.04.2.00001: Plasma
H2.00.04.3.00001: Blood cell production
H2.00.04.4.00001: Postnatal sites of haematopoiesis
H2.00.04.4.01001: Lymphoid tissue
H2.00.05.0.00001: Muscle tissue
H2.00.05.1.00001: Smooth muscle tissue
Document 1:::
H2.00.04.4.01001: Lymphoid tissue
H2.00.05.0.00001: Muscle tissue
H2.00.05.1.00001: Smooth muscle tissue
H2.00.05.2.00001: Striated muscle tissue
H2.00.06.0.00001: Nerve tissue
H2.00.06.1.00001: Neuron
H2.00.06.2.00001: Synapse
H2.00.06.2.00001: Neuroglia
h3.01: Bones
h3.02: Joints
h3.03: Muscles
h3.04: Alimentary system
h3.05: Respiratory system
h3.06: Urinary system
h3.07: Genital system
h3.08:
Document 2:::
In cardiology, the cardiac skeleton, also known as the fibrous skeleton of the heart, is a high-density homogeneous structure of connective tissue that forms and anchors the valves of the heart, and influences the forces exerted by and through them. The cardiac skeleton separates and partitions the atria (the smaller, upper two chambers) from the ventricles (the larger, lower two chambers).The heart's cardiac skeleton comprises four dense connective tissue rings that encircle the mitral and tricuspid atrioventricular (AV) canals and extend to the origins of the pulmonary trunk and aorta. This provides crucial support and structure to the heart while also serving to electrically isolate the atria from the ventricles.
The unique matrix of connective tissue within the cardiac skeleton isolates electrical influence within these defined chambers. In normal anatomy, there is only one conduit for electrical conduction from the upper chambers to the lower chambers, known as the atrioventricular node. The physiologic cardiac skeleton forms a firewall governing autonomic/electrical influence until bordering the bundle of His which further governs autonomic flow to the bundle branches of the ventricles. Understood as such, the cardiac skeleton efficiently centers and robustly funnels electrical energy from the atria to the ventricles.
Structure
The structure of the components of the heart has become an area of increasing interest. The cardiac skeleton binds several bands of dense connective tissue, as collagen, that encircle the bases of the pulmonary trunk, aorta, and all four heart valves. While not a traditionally or "true" or rigid skeleton, it does provide structure and support for the heart, as well as isolate the atria from the ventricles. This is why atrial fibrillation almost never degrades to ventricular fibrillation. In youth, this collagen structure is free of calcium adhesions and is quite flexible. With aging, calcium and other mineral accumulation occur withi
Document 3:::
Myomeres are blocks of skeletal muscle tissue arranged in sequence, commonly found in aquatic chordates. Myomeres are separated from adjacent myomeres by connective fascia (myosepta) and most easily seen in larval fishes or in the olm. Myomere counts are sometimes used for identifying specimens, since their number corresponds to the number of vertebrae in the adults. Location varies, with some species containing these only near the tails, while some have them located near the scapular or pelvic girdles. Depending on the species, myomeres could be arranged in an epaxial or hypaxial manner. Hypaxial refers to ventral muscles and related structures while epaxial refers to more dorsal muscles. The horizontal septum divides these two regions in vertebrates from cyclostomes to gnathostomes. In terrestrial chordates, the myomeres become fused as well as indistinct, due to the disappearance of myosepta.
Shape
The shape of myomeres varies by species. Myomeres are commonly zig-zag, "V" (lancelets), "W" (fishes), or straight (tetrapods)– shaped muscle fibers. Generally, cyclostome myomeres are arranged in vertical strips while those of jawed fishes are folded in a complex matter due to swimming capability evolution. Specifically, myomeres of elasmobranchs and eels are “W”-shaped. Contrastingly, myomeres of tetrapods run vertically and do not display complex folding. Another species with simply-lain myomeres are mudpuppies. Myomeres overlap each other in succession, meaning myomere activation also allows neighboring myomeres to activate.
Myomeres are made up of myoglobin-rich dark muscle as well as white muscle. Dark muscle, generally, functions as slow-twitch muscle fibers while white muscle is composed of fast-twitch fibers.
Function
Specifically, three types of myomeres in fish-like chordates include amphioxine (lancelet), cyclostomine (jawless fish), and gnathostomine (jawed fish). A common function shared by all of these is that they function to flex the body lateral
Document 4:::
Vertebrates
Tendon cells, or tenocytes, are elongated fibroblast type cells. The cytoplasm is stretched between the collagen fibres of the tendon. They have a central cell nucleus with a prominent nucleolus. Tendon cells have a well-developed rough endoplasmic reticulum and they are responsible for synthesis and turnover of tendon fibres and ground substance.
Invertebrates
Tendon cells form a connecting epithelial layer between the muscle and shell in molluscs. In gastropods, for example, the retractor muscles connect to the shell via tendon cells. Muscle cells are attached to the collagenous myo-tendon space via hemidesmosomes. The myo-tendon space is then attached to the base of the tendon cells via basal hemidesmosomes, while apical hemidesmosomes, which sit atop microvilli, attach the tendon cells to a thin layer of collagen. This is in turn attached to the shell via organic fibres which insert into the shell. Molluscan tendon cells appear columnar and contain a large basal cell nucleus. The cytoplasm is filled with granular endoplasmic reticulum and sparse golgi. Dense bundles of microfilaments run the length of the cell connecting the basal to the apical hemidesmosomes.
See also
List of human cell types derived from the germ layers
List of distinct cell types in the adult human body
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Because their cells are arranged in bundles, the appearance of skeletal and cardiac muscles is described as what?
A. quadrant
B. incised
C. striated
D. cylindrical
Answer:
|
|
sciq-5608
|
multiple_choice
|
What human traits are controlled by more than one gene?
|
[
"maladaptive traits",
"polygenic traits",
"autolysis traits",
"mutant traits"
] |
B
|
Relavent Documents:
Document 0:::
The Generalist Genes hypothesis of learning abilities and disabilities was originally coined in an article by Plomin & Kovas (2005).
The Generalist Genes hypothesis suggests that most genes associated with common learning disabilities and abilities are generalist in three ways.
Firstly, the same genes that influence common learning abilities (e.g., high reading aptitude) are also responsible for common learning disabilities (e.g., reading disability): they are strongly genetically correlated.
Secondly, many of the genes associated with one aspect of a learning disability (e.g., vocabulary problems) also influence other aspects of this learning disability (e.g., grammar problems).
Thirdly, genes that influence one learning disability (e.g., reading disability) are largely the same as those that influence other learning disabilities (e.g., mathematics disability).
The Generalist Genes hypothesis has important implications for education, cognitive sciences and molecular genetics.
Document 1:::
Personality traits are patterns of thoughts, feelings and behaviors that reflect the tendency to respond in certain ways under certain circumstances.
Personality is influenced by genetic and environmental factors and associated with mental health. Beside the environment factor, genetic variants can be detected for personality traits. These traits are polygenic. Significant genetic variants are present for most of the behavioral traits. There is a consistency in detection of genetic variants and genomic association for traits derived from pedigree.
Trait theory
The Big Five personality traits, also known as the five-factor model (FFM) or the OCEAN model, is the prevailing model for personality traits. When factor analysis (a statistical technique) is applied to personality survey data, some words or questionnaire items used to describe aspects of personality are often applied to the same person. For example, someone described as conscientious is more likely to be described as "always prepared" rather than "messy". This theory uses descriptors of common language and therefore suggests five broad dimensions commonly used to describe the human personality and psyche.
The five factors are:
Openness to experience (inventive/curious vs. consistent/cautious)
Conscientiousness (efficient/organized vs. easy-going/careless)
Extraversion (outgoing/energetic vs. solitary/reserved)
Agreeableness (friendly/compassionate vs. challenging/detached)
Neuroticism (sensitive/nervous vs. secure/confident).
Methods
The methods mostly used in genomics of personality traits' studies are two: analytic methods and not-analytic ones (such as questionnaires).
Analytic
Analytical techniques that can be used to measure genomics of personality include:
GWAS, genome wide association study is a method used to define markers (these markers are single nucleotide polymorphism, SNPs) across the genomes in order to better understand the contribution of genetics to personality traits. Since
Document 2:::
Genetics is the study of genes and tries to explain what they are and how they work. Genes are how living organisms inherit features or traits from their ancestors; for example, children usually look like their parents because they have inherited their parents' genes. Genetics tries to identify which traits are inherited and to explain how these traits are passed from generation to generation.
Some traits are part of an organism's physical appearance, such as eye color, height or weight. Other sorts of traits are not easily seen and include blood types or resistance to diseases. Some traits are inherited through genes, which is the reason why tall and thin people tend to have tall and thin children. Other traits come from interactions between genes and the environment, so a child who inherited the tendency of being tall will still be short if poorly nourished. The way our genes and environment interact to produce a trait can be complicated. For example, the chances of somebody dying of cancer or heart disease seems to depend on both their genes and their lifestyle.
Genes are made from a long molecule called DNA, which is copied and inherited across generations. DNA is made of simple units that line up in a particular order within it, carrying genetic information. The language used by DNA is called genetic code, which lets organisms read the information in the genes. This information is the instructions for the construction and operation of a living organism.
The information within a particular gene is not always exactly the same between one organism and another, so different copies of a gene do not always give exactly the same instructions. Each unique form of a single gene is called an allele. As an example, one allele for the gene for hair color could instruct the body to produce much pigment, producing black hair, while a different allele of the same gene might give garbled instructions that fail to produce any pigment, giving white hair. Mutations are random
Document 3:::
Complex traits, also known as quantitative traits, are traits that do not behave according to simple Mendelian inheritance laws. More specifically, their inheritance cannot be explained by the genetic segregation of a single gene. Such traits show a continuous range of variation and are influenced by both environmental and genetic factors. Compared to strictly Mendelian traits, complex traits are far more common, and because they can be hugely polygenic, they are studied using statistical techniques such as quantitative genetics and quantitative trait loci (QTL) mapping rather than classical genetics methods. Examples of complex traits include height, circadian rhythms, enzyme kinetics, and many diseases including diabetes and Parkinson's disease. One major goal of genetic research today is to better understand the molecular mechanisms through which genetic variants act to influence complex traits.
History
When Mendel's work on inheritance was rediscovered in 1900, scientists debated whether Mendel's laws could account for the continuous variation observed for many traits. One group known as the biometricians argued that continuous traits such as height were largely heritable, but could not be explained by the inheritance of single Mendelian genetic factors. Work published by Ronald Fisher in 1919 mostly resolved debate by demonstrating that the variation in continuous traits could be accounted for if multiple such factors contributed additively to each trait. However, the number of genes involved in such traits remained undetermined; until recently, genetic loci were expected to have moderate effect sizes and each explain several percent of heritability. After the conclusion of the Human Genome Project in 2001, it seemed that the sequencing and mapping of many individuals would soon allow for a complete understanding of traits' genetic architectures. However, variants discovered through genome-wide association studies (GWASs) accounted for only a small percentag
Document 4:::
Mendelian traits behave according to the model of monogenic or simple gene inheritance in which one gene corresponds to one trait. Discrete traits (as opposed to continuously varying traits such as height) with simple Mendelian inheritance patterns are relatively rare in nature, and many of the clearest examples in humans cause disorders. Discrete traits found in humans are common examples for teaching genetics.
Mendelian model
According to the model of Mendelian inheritance, alleles may be dominant or recessive, one allele is inherited from each parent, and only those who inherit a recessive allele from each parent exhibit the recessive phenotype. Offspring with either one or two copies of the dominant allele will display the dominant phenotype.
Very few phenotypes are purely Mendelian traits. Common violations of the Mendelian model include incomplete dominance, codominance, genetic linkage, environmental effects, and quantitative contributions from a number of genes (see: gene interactions, polygenic inheritance, oligogenic inheritance).
OMIM (Online Mendelian Inheritance in Man) is a comprehensive database of human genotype–phenotype links. Many visible human traits that exhibit high heritability were included in the older McKusick's Mendelian Inheritance in Man. Before the discovery of genotyping, they were used as genetic markers in medicolegal practice, including in cases of disputed paternity.
Human traits with probable or uncertain simple inheritance patterns
See also
Polygenic inheritance
Trait
Gene interaction
Dominance
Homozygote
Heterozygote
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What human traits are controlled by more than one gene?
A. maladaptive traits
B. polygenic traits
C. autolysis traits
D. mutant traits
Answer:
|
|
sciq-2125
|
multiple_choice
|
Large amounts of fuel are stored in skeletal muscles, adipose tissues and what organ?
|
[
"liver",
"skin",
"spleen",
"kidney"
] |
A
|
Relavent Documents:
Document 0:::
An energy budget is a balance sheet of energy income against expenditure. It is studied in the field of Energetics which deals with the study of energy transfer and transformation from one form to another. Calorie is the basic unit of measurement. An organism in a laboratory experiment is an open thermodynamic system, exchanging energy with its surroundings in three ways - heat, work and the potential energy of biochemical compounds.
Organisms use ingested food resources (C=consumption) as building blocks in the synthesis of tissues (P=production) and as fuel in the metabolic process that power this synthesis and other physiological processes (R=respiratory loss). Some of the resources are lost as waste products (F=faecal loss, U=urinary loss). All these aspects of metabolism can be represented in energy units. The basic model of energy budget may be shown as:
P = C - R - U - F or
P = C - (R + U + F) or
C = P + R + U + F
All the aspects of metabolism can be represented in energy units (e.g. joules (J);1 calorie = 4.2 kJ).
Energy used for metabolism will be
R = C - (F + U + P)
Energy used in the maintenance will be
R + F + U = C - P
Endothermy and ectothermy
Energy budget allocation varies for endotherms and ectotherms. Ectotherms rely on the environment as a heat source while endotherms maintain their body temperature through the regulation of metabolic processes. The heat produced in association with metabolic processes facilitates the active lifestyles of endotherms and their ability to travel far distances over a range of temperatures in the search for food. Ectotherms are limited by the ambient temperature of the environment around them but the lack of substantial metabolic heat production accounts for an energetically inexpensive metabolic rate. The energy demands for ectotherms are generally one tenth of that required for endotherms.
Document 1:::
The liver is a major metabolic organ only found in vertebrate animals, which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it is located in the right upper quadrant of the abdomen, below the diaphragm and mostly shielded by the lower right rib cage. Its other metabolic roles include carbohydrate metabolism, the production of hormones, conversion and storage of nutrients such as glucose and glycogen, and the decomposition of red blood cells.
The liver is also an accessory digestive organ that produces bile, an alkaline fluid containing cholesterol and bile acids, which emulsifies and aids the breakdown of dietary fat. The gallbladder, a small hollow pouch that sits just under the right lobe of liver, stores and concentrates the bile produced by the liver, which is later excreted to the duodenum to help with digestion. The liver's highly specialized tissue, consisting mostly of hepatocytes, regulates a wide variety of high-volume biochemical reactions, including the synthesis and breakdown of small and complex organic molecules, many of which are necessary for normal vital functions. Estimates regarding the organ's total number of functions vary, but is generally cited as being around 500.
It is not known how to compensate for the absence of liver function in the long term, although liver dialysis techniques can be used in the short term. Artificial livers have not been developed to promote long-term replacement in the absence of the liver. , liver transplantation is the only option for complete liver failure.
Structure
The liver is a dark reddish brown, wedge-shaped organ with two lobes of unequal size and shape. A human liver normally weighs approximately and has a width of about . There is considerable size variation between individuals, with the standard reference range for men being and for women . It is both the heaviest int
Document 2:::
H2.00.04.4.01001: Lymphoid tissue
H2.00.05.0.00001: Muscle tissue
H2.00.05.1.00001: Smooth muscle tissue
H2.00.05.2.00001: Striated muscle tissue
H2.00.06.0.00001: Nerve tissue
H2.00.06.1.00001: Neuron
H2.00.06.2.00001: Synapse
H2.00.06.2.00001: Neuroglia
h3.01: Bones
h3.02: Joints
h3.03: Muscles
h3.04: Alimentary system
h3.05: Respiratory system
h3.06: Urinary system
h3.07: Genital system
h3.08:
Document 3:::
Animal nutrition focuses on the dietary nutrients needs of animals, primarily those in agriculture and food production, but also in zoos, aquariums, and wildlife management.
Constituents of diet
Macronutrients (excluding fiber and water) provide structural material (amino acids from which proteins are built, and lipids from which cell membranes and some signaling molecules are built) and energy. Some of the structural material can be used to generate energy internally, though the net energy depends on such factors as absorption and digestive effort, which vary substantially from instance to instance. Vitamins, minerals, fiber, and water do not provide energy, but are required for other reasons. A third class dietary material, fiber (i.e., non-digestible material such as cellulose), seems also to be required, for both mechanical and biochemical reasons, though the exact reasons remain unclear.
Molecules of carbohydrates and fats consist of carbon, hydrogen, and oxygen atoms. Carbohydrates range from simple monosaccharides (glucose, fructose, galactose) to complex polysaccharides (starch). Fats are triglycerides, made of assorted fatty acid monomers bound to glycerol backbone. Some fatty acids, but not all, are essential in the diet: they cannot be synthesized in the body. Protein molecules contain nitrogen atoms in addition to carbon, oxygen, and hydrogen. The fundamental components of protein are nitrogen-containing amino acids. Essential amino acids cannot be made by the animal. Some of the amino acids are convertible (with the expenditure of energy) to glucose and can be used for energy production just as ordinary glucose. By breaking down existing protein, some glucose can be produced internally; the remaining amino acids are discarded, primarily as urea in urine. This occurs normally only during prolonged starvation.
Other dietary substances found in plant foods (phytochemicals, polyphenols) are not identified as essential nutrients but appear to impact healt
Document 4:::
Starvation response in animals (including humans) is a set of adaptive biochemical and physiological changes, triggered by lack of food or extreme weight loss, in which the body seeks to conserve energy by reducing the amount of food energy it consumes.
Equivalent or closely related terms include famine response, starvation mode, famine mode, starvation resistance, starvation tolerance, adapted starvation, adaptive thermogenesis, fat adaptation, and metabolic adaptation.
In humans
Ordinarily, the body responds to reduced energy intake by burning fat reserves and consuming muscle and other tissues. Specifically, the body burns fat after first exhausting the contents of the digestive tract along with glycogen reserves stored in liver cells and after significant protein loss. After prolonged periods of starvation, the body uses the proteins within muscle tissue as a fuel source, which results in muscle mass loss.
Magnitude and composition
The magnitude and composition of the starvation response (i.e. metabolic adaptation) was estimated in a study of 8 individuals living in isolation in Biosphere 2 for two years. During their isolation, they gradually lost an average of 15% (range: 9–24%) of their body weight due to harsh conditions. On emerging from isolation, the eight isolated individuals were compared with a 152-person control group that initially had similar physical characteristics. On average, the starvation response of the individuals after isolation was a reduction in daily total energy expenditure. of the starvation response was explained by a reduction in fat-free mass and fat mass. An additional was explained by a reduction in fidgeting. The remaining was statistically insignificant.
General
The energetic requirements of a body are composed of the basal metabolic rate (BMR) and the physical activity level (ERAT, exercise-related activity thermogenesis). This caloric requirement can be met with protein, fat, carbohydrates, or a mixture of those.
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Large amounts of fuel are stored in skeletal muscles, adipose tissues and what organ?
A. liver
B. skin
C. spleen
D. kidney
Answer:
|
|
sciq-1453
|
multiple_choice
|
What do rocket-based systems use to propel itself into space?
|
[
"hydrogen reactions",
"chemical reactions",
"water reactions",
"nuclear reactions"
] |
B
|
Relavent Documents:
Document 0:::
SystemsGo is a classroom program used in the United States promote the study of engineering and the development of work force skills. It is intended to encourage students to pursue careers in science, technology, engineering, and mechanics. It is based in Fredericksburg, Texas. It allows students to learn more about the past, present, and future of rocket technology, as well as use information learned from independent study to complete hands-on projects.
Annual Rocket Meet
Every spring, teams from high schools in the US gather in at several sites to launch their semester project rockets. The program offers high school students three different levels of projects, ranging from a mid-sized rocket traveling to a one mile apogee to rockets weighing several hundred pounds with the potential to reach near-space altitudes.
Program levels
Tsiolkovsky Level : The first stage of the Program, named after the Soviet rocket scientist Konstantin Tsiolkovsky, requires students to propel a research package to an altitude of 5,280 feet (one mile) and to recover it after launch.
Oberth Level : The intermediate stage, named after the German physicist Hermann Oberth, gives students the goal of designing and launching a rocket able to reach transonic velocity while maintaining a maximum altitude of less than 13,000 feet.
Goddard Level : The most advanced level, named after the American engineer and rocket scientist Robert H. Goddard, challenges students to create a rocket from scratch that can reach an altitude of 50,000 feet, which is considered to fall within the near space region of Earth’s atmosphere. Rockets for this level are often several hundred pounds and can reach velocities of Mach 3 or even Mach 4. Launches for this level are hosted by the US Army at the White Sands Missile Range, New Mexico.
Recognition
The SystemsGo program has been recognized and supported by such organizations as SpaceX, Dow Chemical, Boeing, NASA, and The Space Foundation.
Document 1:::
Astronauts hold a variety of ranks and positions. Each of these roles carries responsibilities that are essential to the operation of a spacecraft. A spacecraft's cockpit, filled with sophisticated equipment, requires skills differing from those used to manage the scientific equipment on board, and so on.
NASA ranks and positions
Ranks
Members of the NASA Astronaut Corps hold one of two ranks. Astronaut Candidate is the rank of those training to be NASA astronauts.
Upon graduation, candidates are promoted to Astronaut and receive their Astronaut Pin. The pin is issued in two grades, silver and gold, with the silver pin awarded to candidates who have successfully completed astronaut training and the gold pin to astronauts who have flown in space.
Chief of the Astronaut Office is a position, not a rank.
Positions
Roscosmos and Soviet space program ranks and positions
Ranks
Cosmonauts are professional space travellers from Russia. After initial training, cosmonauts are assigned as either a test-cosmonaut (космонавт-испытатель, kosmonavt-ispytatel') or a research-cosmonaut (космонавт-исследователь, kosmonavt-issledovatel'). A test-cosmonaut has a more difficult preparation than a research-cosmonaut and can be the commander or the flight engineer of a spacecraft, while a research-cosmonaut cannot.
Higher ranks include pilot-cosmonaut, test-cosmonaut instructor, and research-cosmonaut instructor.
Pilot-Cosmonaut of the Russian Federation is a title that is presented to all cosmonauts who fly for the Russian space program.
Positions
China National Space Administration positions
Ranks
Similarly to NASA, members of the China National Space Administration (CNSA) hold one of two ranks. Astronaut Candidate is the rank of those training to be CNSA astronauts. The positions of Spacecraft Pilot, Flight Engineer, and Mission Payload Specialist were listed in the announcement for the Group 3 selection.
Upon graduation, candidates are promoted to Astronaut.
Position
Document 2:::
A sodium bicarbonate rocket (sometimes called an Alka-Seltzer rocket) is a model rocket fashioned from a 35mm film canister and propelled by the pressure of a gas, often carbon dioxide, generated from the reaction of an acid with sodium bicarbonate. Sodium bicarbonate rockets are often used in science classes to demonstrate principles of chemistry and physics.
In the experiment, a film canister is filled with water, an effervescent tablet (commonly Alka-Seltzer) is added and the canister tightly sealed. After a short time, the pressure of the carbon dioxide is great enough to cause the body of the canister to be launched into the air with a popping sound. The canister may be embellished with paper fins to resemble more closely a real rocket.
Various experiments and lessons can center around the use of a bicarbonate rocket. For example, students are sometimes asked to experiment with the amounts of water and Alka-Seltzer to find the combination which propels the rocket the greatest distance. Alternatively they may derive equations to calculate the speed and velocity of the rocket from the distance it travels.
In rocketry, a chemical reaction rapidly creates gas that is expelled in one direction from its container (the rocket engine); momentum forces the rocket in the opposite direction. The alka-seltzer rocket experiment demonstrates Newton's third law. The film canister rocket has a buildup of gas that wants to come out of the weakest spot making all the gas come out at once through the hole at the bottom. The gas comes out from the underside and pushes the rocket up. After it gets pushed up, air resistance slows it down and gravity pulls it down to earth. The film canister accelerates quickly because it has very little mass.
The film canister rocket uses a solid fuel mixed with a liquid fuel to create a gas that escapes out of the bottom. The gas is carbon dioxide (CO2), the liquid is water (H2O), and the solid is an effervescent tablet. When the H2O is mixed wi
Document 3:::
The Kuwait Space Rocket (KSR), is a Kuwaiti project to build and launch the first suborbital liquid bi-propellant rocket in Arabia. The project is intended to be the first step towards starting a space industry in the country and a launch service provider in the GCC region. The project is divided into two phases with two separate vehicles. An initial testing phase with KSR-1 as a test vehicle capable of reaching an altitude of and a more expansive suborbital test phase with the KSR-2 planned to fly to an altitude of . in May 16 Ambition-1 launched but had a malfunction with the parachute and crashed in free fall.
History
The project began in January 2018 for conceptual design and planning. The team started the fabrication of KSR-1 in early 2019, and as of January 2020, KSR-1 was fully built.
KSR-1
KSR-1 is a vertically-launched single stage rocket. It uses a liquid bi-propellant rocket engine burning methanol as fuel and nitrous oxide as the oxidizer. KSR-1 is intended to be a test vehicle for the development of KSR-2, the goal of which is to reach space. As such, all the major components and technologies that are expected to be used in KSR-2 are present in KSR-1. The main components of KSR 1 are the engine—consisting of the injector, nozzle, and cooling jacket— with fuel and oxidizer tanks, a nitrogen gas tank, and various valves and pressure regulators.
KSR-1 Development Process
Engine Fabrication
The KSR-1 engine was built locally in Kuwait and it utilizes a pressure fed cycle. The engine utilizes the nitrous not only as an oxidizer but as a cooling agent, that flows around the nozzle and back into the injector again.
Cold Flow Testing
The KSR team performed a cold flow testing in October 2019 to verify the engine's flow rate and plumbing.
Static Testing
KSR performed a static testing of the Injector in November 2019.
Structural Assembly
The KSR-1 was fully assembled and presented at the Kuwait Aviation Show 2020.
KSR-2
KSR-2 is a planned liquid
Document 4:::
A payload specialist (PS) was an individual selected and trained by commercial or research organizations for flights of a specific payload on a NASA Space Shuttle mission. People assigned as payload specialists included individuals selected by the research community, a company or consortium flying a commercial payload aboard the spacecraft, and non-NASA astronauts designated by international partners.
The term refers to both the individual and to the position on the Shuttle crew.
History
The National Aeronautics and Space Act of 1958 states that NASA should provide the "widest practicable and appropriate dissemination of information concerning its activities and the results thereof". The Naugle panel of 1982 concluded that carrying civilians—those not part of the NASA Astronaut Corps—on the Space Shuttle was part of "the purpose of adding to the public's understanding of space flight".
Payload specialists usually fly for a single specific mission. Chosen outside the standard NASA mission specialist selection process, they are exempt from certain NASA requirements such as colorblindness. Roger Crouch and Ulf Merbold are examples of those who flew in space despite not meeting NASA physical requirements; the agency's director of crew training Jim Bilodeau said in April 1981 "we'll be able to take everybody but the walking wounded". Payload specialists were not required to be United States citizens, but had to be approved by NASA and undergo rigorous but shorter training. In contrast, a Space Shuttle mission specialist was selected as a NASA astronaut first and then assigned to a mission.
Payload specialists on early missions were technical experts to join specific payloads such as a commercial or scientific satellite. On Spacelab and other missions with science components, payload specialists were scientists with expertise in specific experiments. The term also applied to representatives from partner nations who were given the opportunity of a first flight on boar
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What do rocket-based systems use to propel itself into space?
A. hydrogen reactions
B. chemical reactions
C. water reactions
D. nuclear reactions
Answer:
|
|
sciq-1441
|
multiple_choice
|
In the lungs, bicarbonate is transported back into the red blood cells in exchange for what?
|
[
"glucose",
"phosphate",
"chloride",
"oxygen"
] |
C
|
Relavent Documents:
Document 0:::
In acid base physiology, the Davenport diagram is a graphical tool, developed by Horace W. Davenport, that allows a clinician or investigator to describe blood bicarbonate concentrations and blood pH following a respiratory and/or metabolic acid-base disturbance. The diagram depicts a three-dimensional surface describing all possible states of chemical equilibria between gaseous carbon dioxide, aqueous bicarbonate and aqueous protons at the physiologically complex interface of the alveoli of the lungs and the alveolar capillaries. Although the surface represented in the diagram is experimentally determined, the Davenport diagram is rarely used in the clinical setting, but allows the investigator to envision the effects of physiological changes on blood acid-base chemistry. For clinical use there are two recent innovations: an Acid-Base Diagram which provides Text Descriptions for the abnormalities and a High Altitude Version that provides text descriptions appropriate for the altitude.
Derivation
When a sample of blood is exposed to air, either in the alveoli of the lung or in an in vitro laboratory experiment, carbon dioxide in the air rapidly enters into equilibrium with carbon dioxide derivatives and other species in the aqueous solution. Figure 1 illustrates the most important equilibrium reactions of carbon dioxide in blood relating to acid-base physiology:
Note that in this equation, the HB/B- buffer system represents all non-bicarbonate buffers present in the blood, such as hemoglobin in its various protonated and deprotonated states. Because many different non-bicarbonate buffers are present in human blood, the final equilibrium state reached at any given pCO2 is highly complex and cannot be readily predicted using theory alone. By depicting experimental results, the Davenport diagram provides a simple approach to describing the behavior of this complex system.
Figure 2 shows a Davenport diagram as commonly depicted in textbooks and the literature. To un
Document 1:::
Chloride shift (also known as the Hamburger phenomenon or lineas phenomenon, named after Hartog Jakob Hamburger) is a process which occurs in a cardiovascular system and refers to the exchange of bicarbonate (HCO3−) and chloride (Cl−) across the membrane of red blood cells (RBCs).
Mechanism
Carbon dioxide (CO2) is produced in tissues as a byproduct of normal metabolism. It dissolves in the solution of blood plasma and into red blood cells (RBC), where carbonic anhydrase catalyzes its hydration to carbonic acid (H2CO3). Carbonic acid then spontaneously dissociates to form bicarbonate Ions (HCO3−) and a hydrogen ion (H+). In response to the decrease in intracellular pCO2, more CO2 passively diffuses into the cell.
Cell membranes are generally impermeable to charged ions (i.e. H+, HCO3− ) but RBCs are able to exchange bicarbonate for chloride using the anion exchanger protein Band 3. Thus, the rise in intracellular bicarbonate leads to bicarbonate export and chloride intake. The term "chloride shift" refers to this exchange. Consequently, chloride concentration is lower in systemic venous blood than in systemic arterial blood: high venous pCO2 leads to bicarbonate production in RBCs, which then leaves the RBC in exchange for chloride coming in.
The opposite process occurs in the pulmonary capillaries of the lungs when the PO2 rises and PCO2 falls, and the Haldane effect occurs (release of CO2 from hemoglobin during oxygenation). This releases hydrogen ions from hemoglobin, increases free H+ concentration within RBCs, and shifts the equilibrium towards CO2 and water formation from bicarbonate. The subsequent decrease in intracellular bicarbonate concentration reverses chloride-bicarbonate exchange: bicarbonate moves into the cell in exchange for chloride moving out. Inward movement of bicarbonate via the Band 3 exchanger allows carbonic anhydrase to convert it to CO2 for expiration.
The chloride shift may also regulate the affinity of hemoglobin for oxygen through t
Document 2:::
2,3-Bisphosphoglyceric acid (conjugate base 2,3-bisphosphoglycerate) (2,3-BPG), also known as 2,3-diphosphoglyceric acid (conjugate base 2,3-diphosphoglycerate) (2,3-DPG), is a three-carbon isomer of the glycolytic intermediate 1,3-bisphosphoglyceric acid (1,3-BPG).
-2,3-BPG is present in human red blood cells (RBC; erythrocyte) at approximately 5 mmol/L. It binds with greater affinity to deoxygenated hemoglobin (e.g., when the red blood cell is near respiring tissue) than it does to oxygenated hemoglobin (e.g., in the lungs) due to conformational differences: 2,3-BPG (with an estimated size of about 9 Å) fits in the deoxygenated hemoglobin conformation (with an 11-Angstrom pocket), but not as well in the oxygenated conformation (5 Angstroms). It interacts with deoxygenated hemoglobin beta subunits and decreases the affinity for oxygen and allosterically promotes the release of the remaining oxygen molecules bound to the hemoglobin. Therefore, it enhances the ability of RBCs to release oxygen near tissues that need it most. 2,3-BPG is thus an allosteric effector.
Its function was discovered in 1967 by Reinhold Benesch and Ruth Benesch.
Metabolism
2,3-BPG is formed from 1,3-BPG by the enzyme BPG mutase. It can then be broken down by 2,3-BPG phosphatase to form 3-phosphoglycerate. Its synthesis and breakdown are, therefore, a way around a step of glycolysis, with the net expense of one ATP per molecule of 2,3-BPG generated as the high-energy carboxylic acid-phosphate mixed anhydride bond is cleaved by bisphosphoglycerate mutase.
Document 3:::
A blood substitute (also called artificial blood or blood surrogate) is a substance used to mimic and fulfill some functions of biological blood. It aims to provide an alternative to blood transfusion, which is transferring blood or blood-based products from one person into another. Thus far, there are no well-accepted oxygen-carrying blood substitutes, which is the typical objective of a red blood cell transfusion; however, there are widely available non-blood volume expanders for cases where only volume restoration is required. These are helping doctors and surgeons avoid the risks of disease transmission and immune suppression, address the chronic blood donor shortage, and address the concerns of Jehovah's Witnesses and others who have religious objections to receiving transfused blood.
The main categories of "oxygen-carrying" blood substitutes being pursued are hemoglobin-based oxygen carriers (HBOC) and perfluorocarbon emulsions. Oxygen therapeutics are in clinical trials in the U.S. and European Union, and Hemopure is available in South Africa.
History
After William Harvey discovered blood pathways in 1616, many people tried to use fluids such as beer, urine, milk, and non-human animal blood as blood substitute. Sir Christopher Wren suggested wine and opium as blood substitute.
At the beginning of the 20th century, the development of modern transfusion medicine initiated through the work of Landsteiner and co-authors opened the possibility to understanding the general principle of blood group serology. Simultaneously, significant progress was made in the fields of heart and circulation physiology as well as in the understanding of the mechanism of oxygen transport and tissue oxygenation.
Restrictions in applied transfusion medicine, especially in disaster situations such as World War II, laid the grounds for accelerated research in the field of blood substitutes. Early attempts and optimism in developing blood substitutes were very quickly confronted with
Document 4:::
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the circulatory system is also known as peripheral blood, and the blood cells it carries, peripheral blood cells.
Blood is composed of blood cells suspended in blood plasma. Plasma, which constitutes 55% of blood fluid, is mostly water (92% by volume), and contains proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and blood cells themselves. Albumin is the main protein in plasma, and it functions to regulate the colloidal osmotic pressure of blood. The blood cells are mainly red blood cells (also called RBCs or erythrocytes), white blood cells (also called WBCs or leukocytes), and in mammals platelets (also called thrombocytes). The most abundant cells in vertebrate blood are red blood cells. These contain hemoglobin, an iron-containing protein, which facilitates oxygen transport by reversibly binding to this respiratory gas thereby increasing its solubility in blood. In contrast, carbon dioxide is mostly transported extracellularly as bicarbonate ion transported in plasma.
Vertebrate blood is bright red when its hemoglobin is oxygenated and dark red when it is deoxygenated.
Some animals, such as crustaceans and mollusks, use hemocyanin to carry oxygen, instead of hemoglobin. Insects and some mollusks use a fluid called hemolymph instead of blood, the difference being that hemolymph is not contained in a closed circulatory system. In most insects, this "blood" does not contain oxygen-carrying molecules such as hemoglobin because their bodies are small enough for their tracheal system to suffice for supplying oxygen.
Jawed vertebrates have an adaptive immune system, based largely on white blood cells. White blood cells help to resist infections and parasite
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
In the lungs, bicarbonate is transported back into the red blood cells in exchange for what?
A. glucose
B. phosphate
C. chloride
D. oxygen
Answer:
|
|
sciq-201
|
multiple_choice
|
What is the name for biochemical compounds that consist of one or more chains of small molecules called amino acids?
|
[
"protons",
"proteins",
"lipids",
"hormones"
] |
B
|
Relavent Documents:
Document 0:::
This is a list of articles that describe particular biomolecules or types of biomolecules.
A
For substances with an A- or α- prefix such as
α-amylase, please see the parent page (in this case Amylase).
A23187 (Calcimycin, Calcium Ionophore)
Abamectine
Abietic acid
Acetic acid
Acetylcholine
Actin
Actinomycin D
Adenine
Adenosmeme
Adenosine diphosphate (ADP)
Adenosine monophosphate (AMP)
Adenosine triphosphate (ATP)
Adenylate cyclase
Adiponectin
Adonitol
Adrenaline, epinephrine
Adrenocorticotropic hormone (ACTH)
Aequorin
Aflatoxin
Agar
Alamethicin
Alanine
Albumins
Aldosterone
Aleurone
Alpha-amanitin
Alpha-MSH (Melaninocyte stimulating hormone)
Allantoin
Allethrin
α-Amanatin, see Alpha-amanitin
Amino acid
Amylase (also see α-amylase)
Anabolic steroid
Anandamide (ANA)
Androgen
Anethole
Angiotensinogen
Anisomycin
Antidiuretic hormone (ADH)
Anti-Müllerian hormone (AMH)
Arabinose
Arginine
Argonaute
Ascomycin
Ascorbic acid (vitamin C)
Asparagine
Aspartic acid
Asymmetric dimethylarginine
ATP synthase
Atrial-natriuretic peptide (ANP)
Auxin
Avidin
Azadirachtin A – C35H44O16
B
Bacteriocin
Beauvericin
beta-Hydroxy beta-methylbutyric acid
beta-Hydroxybutyric acid
Bicuculline
Bilirubin
Biopolymer
Biotin (Vitamin H)
Brefeldin A
Brassinolide
Brucine
Butyric acid
C
Document 1:::
A biomolecule or biological molecule is a loosely used term for molecules present in organisms that are essential to one or more typically biological processes, such as cell division, morphogenesis, or development. Biomolecules include the primary metabolites which are large macromolecules (or polyelectrolytes) such as proteins, carbohydrates, lipids, and nucleic acids, as well as small molecules such as vitamins and hormones. A more general name for this class of material is biological materials. Biomolecules are an important element of living organisms, those biomolecules are often endogenous, produced within the organism but organisms usually need exogenous biomolecules, for example certain nutrients, to survive.
Biology and its subfields of biochemistry and molecular biology study biomolecules and their reactions. Most biomolecules are organic compounds, and just four elements—oxygen, carbon, hydrogen, and nitrogen—make up 96% of the human body's mass. But many other elements, such as the various biometals, are also present in small amounts.
The uniformity of both specific types of molecules (the biomolecules) and of certain metabolic pathways are invariant features among the wide diversity of life forms; thus these biomolecules and metabolic pathways are referred to as "biochemical universals" or "theory of material unity of the living beings", a unifying concept in biology, along with cell theory and evolution theory.
Types of biomolecules
A diverse range of biomolecules exist, including:
Small molecules:
Lipids, fatty acids, glycolipids, sterols, monosaccharides
Vitamins
Hormones, neurotransmitters
Metabolites
Monomers, oligomers and polymers:
Nucleosides and nucleotides
Nucleosides are molecules formed by attaching a nucleobase to a ribose or deoxyribose ring. Examples of these include cytidine (C), uridine (U), adenosine (A), guanosine (G), and thymidine (T).
Nucleosides can be phosphorylated by specific kinases in the cell, producing nucl
Document 2:::
This is a list of topics in molecular biology. See also index of biochemistry articles.
Document 3:::
The metabolome refers to the complete set of small-molecule chemicals found within a biological sample. The biological sample can be a cell, a cellular organelle, an organ, a tissue, a tissue extract, a biofluid or an entire organism. The small molecule chemicals found in a given metabolome may include both endogenous metabolites that are naturally produced by an organism (such as amino acids, organic acids, nucleic acids, fatty acids, amines, sugars, vitamins, co-factors, pigments, antibiotics, etc.) as well as exogenous chemicals (such as drugs, environmental contaminants, food additives, toxins and other xenobiotics) that are not naturally produced by an organism.
In other words, there is both an endogenous metabolome and an exogenous metabolome. The endogenous metabolome can be further subdivided to include a "primary" and a "secondary" metabolome (particularly when referring to plant or microbial metabolomes). A primary metabolite is directly involved in the normal growth, development, and reproduction. A secondary metabolite is not directly involved in those processes, but usually has important ecological function. Secondary metabolites may include pigments, antibiotics or waste products derived from partially metabolized xenobiotics. The study of the metabolome is called metabolomics.
Origins
The word metabolome appears to be a blending of the words "metabolite" and "chromosome". It was constructed to imply that metabolites are indirectly encoded by genes or act on genes and gene products. The term "metabolome" was first used in 1998 and was likely coined to match with existing biological terms referring to the complete set of genes (the genome), the complete set of proteins (the proteome) and the complete set of transcripts (the transcriptome). The first book on metabolomics was published in 2003. The first journal dedicated to metabolomics (titled simply "Metabolomics") was launched in 2005 and is currently edited by Prof. Roy Goodacre. Some of the m
Document 4:::
Bioorganic chemistry is a scientific discipline that combines organic chemistry and biochemistry. It is that branch of life science that deals with the study of biological processes using chemical methods. Protein and enzyme function are examples of these processes.
Sometimes biochemistry is used interchangeably for bioorganic chemistry; the distinction being that bioorganic chemistry is organic chemistry that is focused on the biological aspects. While biochemistry aims at understanding biological processes using chemistry, bioorganic chemistry attempts to expand organic-chemical researches (that is, structures, synthesis, and kinetics) toward biology. When investigating metalloenzymes and cofactors, bioorganic chemistry overlaps bioinorganic chemistry.
Sub disciplines
Biophysical organic chemistry is a term used when attempting to describe intimate details of molecular recognition by bioorganic chemistry.
Natural product chemistry is the process of Identifying compounds found in nature to determine their properties. Compound discoveries have and often lead to medicinal uses, development of herbicides and insecticides.
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What is the name for biochemical compounds that consist of one or more chains of small molecules called amino acids?
A. protons
B. proteins
C. lipids
D. hormones
Answer:
|
|
sciq-4685
|
multiple_choice
|
What do animals store with the help of saturated fatty acids?
|
[
"sugar",
"oxygen",
"protein",
"energy"
] |
D
|
Relavent Documents:
Document 0:::
Animal nutrition focuses on the dietary nutrients needs of animals, primarily those in agriculture and food production, but also in zoos, aquariums, and wildlife management.
Constituents of diet
Macronutrients (excluding fiber and water) provide structural material (amino acids from which proteins are built, and lipids from which cell membranes and some signaling molecules are built) and energy. Some of the structural material can be used to generate energy internally, though the net energy depends on such factors as absorption and digestive effort, which vary substantially from instance to instance. Vitamins, minerals, fiber, and water do not provide energy, but are required for other reasons. A third class dietary material, fiber (i.e., non-digestible material such as cellulose), seems also to be required, for both mechanical and biochemical reasons, though the exact reasons remain unclear.
Molecules of carbohydrates and fats consist of carbon, hydrogen, and oxygen atoms. Carbohydrates range from simple monosaccharides (glucose, fructose, galactose) to complex polysaccharides (starch). Fats are triglycerides, made of assorted fatty acid monomers bound to glycerol backbone. Some fatty acids, but not all, are essential in the diet: they cannot be synthesized in the body. Protein molecules contain nitrogen atoms in addition to carbon, oxygen, and hydrogen. The fundamental components of protein are nitrogen-containing amino acids. Essential amino acids cannot be made by the animal. Some of the amino acids are convertible (with the expenditure of energy) to glucose and can be used for energy production just as ordinary glucose. By breaking down existing protein, some glucose can be produced internally; the remaining amino acids are discarded, primarily as urea in urine. This occurs normally only during prolonged starvation.
Other dietary substances found in plant foods (phytochemicals, polyphenols) are not identified as essential nutrients but appear to impact healt
Document 1:::
An unsaturated fat is a fat or fatty acid in which there is at least one double bond within the fatty acid chain. A fatty acid chain is monounsaturated if it contains one double bond, and polyunsaturated if it contains more than one double bond.
A saturated fat has no carbon to carbon double bonds, so the maximum possible number of hydrogens bonded to the carbons, and is "saturated" with hydrogen atoms. To form carbon to carbon double bonds, hydrogen atoms are removed from the carbon chain. In cellular metabolism, unsaturated fat molecules contain less energy (i.e., fewer calories) than an equivalent amount of saturated fat. The greater the degree of unsaturation in a fatty acid (i.e., the more double bonds in the fatty acid) the more vulnerable it is to lipid peroxidation (rancidity). Antioxidants can protect unsaturated fat from lipid peroxidation.
Composition of common fats
In chemical analysis, fats are broken down to their constituent fatty acids, which can be analyzed in various ways. In one approach, fats undergo transesterification to give fatty acid methyl esters (FAMEs), which are amenable to separation and quantitation using by gas chromatography. Classically, unsaturated isomers were separated and identified by argentation thin-layer chromatography.
The saturated fatty acid components are almost exclusively stearic (C18) and palmitic acids (C16). Monounsaturated fats are almost exclusively oleic acid. Linolenic acid comprises most of the triunsaturated fatty acid component.
Chemistry and nutrition
Although polyunsaturated fats are protective against cardiac arrhythmias, a study of post-menopausal women with a relatively low fat intake showed that polyunsaturated fat is positively associated with progression of coronary atherosclerosis, whereas monounsaturated fat is not. This probably is an indication of the greater vulnerability of polyunsaturated fats to lipid peroxidation, against which vitamin E has been shown to be protective.
Examples
Document 2:::
Fatty acid metabolism consists of various metabolic processes involving or closely related to fatty acids, a family of molecules classified within the lipid macronutrient category. These processes can mainly be divided into (1) catabolic processes that generate energy and (2) anabolic processes where they serve as building blocks for other compounds.
In catabolism, fatty acids are metabolized to produce energy, mainly in the form of adenosine triphosphate (ATP). When compared to other macronutrient classes (carbohydrates and protein), fatty acids yield the most ATP on an energy per gram basis, when they are completely oxidized to CO2 and water by beta oxidation and the citric acid cycle. Fatty acids (mainly in the form of triglycerides) are therefore the foremost storage form of fuel in most animals, and to a lesser extent in plants.
In anabolism, intact fatty acids are important precursors to triglycerides, phospholipids, second messengers, hormones and ketone bodies. For example, phospholipids form the phospholipid bilayers out of which all the membranes of the cell are constructed from fatty acids. Phospholipids comprise the plasma membrane and other membranes that enclose all the organelles within the cells, such as the nucleus, the mitochondria, endoplasmic reticulum, and the Golgi apparatus. In another type of anabolism, fatty acids are modified to form other compounds such as second messengers and local hormones. The prostaglandins made from arachidonic acid stored in the cell membrane are probably the best-known of these local hormones.
Fatty acid catabolism
Fatty acids are stored as triglycerides in the fat depots of adipose tissue. Between meals they are released as follows:
Lipolysis, the removal of the fatty acid chains from the glycerol to which they are bound in their storage form as triglycerides (or fats), is carried out by lipases. These lipases are activated by high epinephrine and glucagon levels in the blood (or norepinephrine secreted by s
Document 3:::
Relatively speaking, the brain consumes an immense amount of energy in comparison to the rest of the body. The mechanisms involved in the transfer of energy from foods to neurons are likely to be fundamental to the control of brain function. Human bodily processes, including the brain, all require both macronutrients, as well as micronutrients.
Insufficient intake of selected vitamins, or certain metabolic disorders, may affect cognitive processes by disrupting the nutrient-dependent processes within the body that are associated with the management of energy in neurons, which can subsequently affect synaptic plasticity, or the ability to encode new memories.
Macronutrients
The human brain requires nutrients obtained from the diet to develop and sustain its physical structure and cognitive functions. Additionally, the brain requires caloric energy predominately derived from the primary macronutrients to operate. The three primary macronutrients include carbohydrates, proteins, and fats. Each macronutrient can impact cognition through multiple mechanisms, including glucose and insulin metabolism, neurotransmitter actions, oxidative stress and inflammation, and the gut-brain axis. Inadequate macronutrient consumption or proportion could impair optimal cognitive functioning and have long-term health implications.
Carbohydrates
Through digestion, dietary carbohydrates are broken down and converted into glucose, which is the sole energy source for the brain. Optimal brain function relies on adequate carbohydrate consumption, as carbohydrates provide the quickest source of glucose for the brain. Glucose deficiencies such as hypoglycaemia reduce available energy for the brain and impair all cognitive processes and performance. Additionally, situations with high cognitive demand, such as learning a new task, increase brain glucose utilization, depleting blood glucose stores and initiating the need for supplementation.
Complex carbohydrates, especially those with high d
Document 4:::
Field metabolic rate (FMR) refers to a measurement of the metabolic rate of a free-living animal.
Method
Measurement of the Field metabolic rate is made using the doubly labeled water method, although alternative techniques, such as monitoring heart rates, can also be used. The advantages and disadvantages of the alternative approaches have been reviewed by Butler, et al. Several summary reviews have been published.
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What do animals store with the help of saturated fatty acids?
A. sugar
B. oxygen
C. protein
D. energy
Answer:
|
|
sciq-339
|
multiple_choice
|
What are the contacts between neurons called?
|
[
"synapses",
"impulses",
"neurapses",
"electrodes"
] |
A
|
Relavent Documents:
Document 0:::
Microelectrode arrays (MEAs) (also referred to as multielectrode arrays) are devices that contain multiple (tens to thousands) microelectrodes through which neural signals are obtained or delivered, essentially serving as neural interfaces that connect neurons to electronic circuitry. There are two general classes of MEAs: implantable MEAs, used in vivo, and non-implantable MEAs, used in vitro.
Theory
Neurons and muscle cells create ion currents through their membranes when excited, causing a change in voltage between the inside and the outside of the cell. When recording, the electrodes on an MEA transduce the change in voltage from the environment carried by ions into currents carried by electrons (electronic currents). When stimulating, electrodes transduce electronic currents into ionic currents through the media. This triggers the voltage-gated ion channels on the membranes of the excitable cells, causing the cell to depolarize and trigger an action potential if it is a neuron or a twitch if it is a muscle cell.
The size and shape of a recorded signal depend upon several factors: the nature of the medium in which the cell or cells are located (e.g. the medium's electrical conductivity, capacitance, and homogeneity); the nature of contact between the cells and the MEA electrode (e.g. area of contact and tightness); the nature of the MEA electrode itself (e.g. its geometry, impedance, and noise); the analog signal processing (e.g. the system's gain, bandwidth, and behavior outside of cutoff frequencies); and the data sampling properties (e.g. sampling rate and digital signal processing). For the recording of a single cell that partially covers a planar electrode, the voltage at the contact pad is approximately equal to the voltage of the overlapping region of the cell and electrode multiplied by the ratio the surface area of the overlapping region to the area of the entire electrode, or:
assuming the area around an electrode is well-insulated and has a very s
Document 1:::
In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell.
Synapses are essential to the transmission of nervous impulses from one neuron to another. Neurons are specialized to pass signals to individual target cells, and synapses are the means by which they do so. At a synapse, the plasma membrane of the signal-passing neuron (the presynaptic neuron) comes into close apposition with the membrane of the target (postsynaptic) cell. Both the presynaptic and postsynaptic sites contain extensive arrays of molecular machinery that link the two membranes together and carry out the signaling process. In many synapses, the presynaptic part is located on an axon and the postsynaptic part is located on a dendrite or soma. Astrocytes also exchange information with the synaptic neurons, responding to synaptic activity and, in turn, regulating neurotransmission. Synapses (at least chemical synapses) are stabilized in position by synaptic adhesion molecules (SAMs) projecting from both the pre- and post-synaptic neuron and sticking together where they overlap; SAMs may also assist in the generation and functioning of synapses.
History
Santiago Ramón y Cajal proposed that neurons are not continuous throughout the body, yet still communicate with each other, an idea known as the neuron doctrine. The word "synapse" was introduced in 1897 by the English neurophysiologist Charles Sherrington in Michael Foster's Textbook of Physiology. Sherrington struggled to find a good term that emphasized a union between two separate elements, and the actual term "synapse" was suggested by the English classical scholar Arthur Woollgar Verrall, a friend of Foster. The word was derived from the Greek synapsis (), meaning "conjunction", which in turn derives from synaptein (), from syn () "together" and haptein () "to fasten".
However, while the synaptic gap remained a theoretical co
Document 2:::
Gregory A. Clark is a professor in the Departments of Biomedical Engineering and Computer Science at the University of Utah; he is also the Director for the Center for Neural Interfaces at the University of Utah. Dr. Clark’s current research is in neuroprostheses, bioengineering, sensory information processing, and electrophysiological and computational analyses of neuronal plasticity in simple systems.
Education
Dr. Clark studied Psychology at Brown University; after receiving his B.A., Dr.Clark completed his Ph.D. with the Department of Psychobiology at the University of California, Irvine.
Career and research
In 1981 Dr. Clark lectured for the Department of Psychology at Stanford University. Upon leaving Stanford, Dr. Clark went to the College of Physicians and Surgeons at Columbia University. While there, he completed a postdoctoral fellowship at the Center for Neurobiology and Behavior between 1982 and 1984, continued on as a research associate at the Howard Hughes Medical Institute for Molecular Neurobiology between 1984 and 1988, and became an instructor of clinical neurobiology for the Department of Psychiatry and Center for Neurobiology and Behavior from 1986 to 1988.
Following his time at Columbia, Dr. Clark became an assistant professor in the Department of Psychology at Princeton University from 1988 to 1996.
After his time at Princeton, he became an associate professor in the Department of Biomedical Engineering at the University of Utah in 1996, gaining tenure in 2001. In 2009 he became an adjunct associate professor in the Department of Computer Science at the University of Utah. In 2015, he became the director of the Center for Neural Interfaces.
Dr. Clark has made contributions to a variety of research areas, including neuroprostheses, bioengineering, sensory information processing, and electrophysiological and computational analyses of neuronal plasticity in simple systems (Aplysia and Hermissenda). Specifically, these contributions have in
Document 3:::
A cultured neuronal network is a cell culture of neurons that is used as a model to study the central nervous system, especially the brain. Often, cultured neuronal networks are connected to an input/output device such as a multi-electrode array (MEA), thus allowing two-way communication between the researcher and the network. This model has proved to be an invaluable tool to scientists studying the underlying principles behind neuronal learning, memory, plasticity, connectivity, and information processing.
Cultured neurons are often connected via computer to a real or simulated robotic component, creating a hybrot or animat, respectively. Researchers can then thoroughly study learning and plasticity in a realistic context, where the neuronal networks are able to interact with their environment and receive at least some artificial sensory feedback. One example of this can be seen in the Multielectrode Array Art (MEART) system developed by the Potter Research Group at the Georgia Institute of Technology in collaboration with SymbioticA, The Centre for Excellence in Biological Art, at the University of Western Australia. Another example can be seen in the neurally controlled animat.
Use as a model
Advantages
The use of cultured neuronal networks as a model for their in vivo counterparts has been an indispensable resource for decades. It allows researchers to investigate neuronal activity in a much more controlled environment than would be possible in a live organism. Through this mechanism researchers have gleaned important information about the mechanisms behind learning and memory.
A cultured neuronal network allows researchers to observe neuronal activity from several vantage points. Electrophysiological recording and stimulation can take place either across the network or locally via an MEA, and the network development can be visually observed using microscopy techniques. Moreover, chemical analysis of the neurons and their environment is more easily accomplis
Document 4:::
In neuroethology and the study of learning, anti-Hebbian learning describes a particular class of learning rule by which synaptic plasticity can be controlled. These rules are based on a reversal of Hebb's postulate, and therefore can be simplistically understood as dictating reduction of the strength of synaptic connectivity between neurons following a scenario in which a neuron directly contributes to production of an action potential in another neuron.
Evidence from neuroethology
Neuroethological study has provided strong evidence for the existence of a system which adheres to an anti-Hebbian learning rule. Research on the mormyrid electric fish has demonstrated that the electrosensory lateral-line lobe (ELL) receives sensory input from knollenorgans (electroreceptive sensory organs) which utilize a self-generated electrical discharge (called an EOD; electric organ discharge) to extract information from the environment about objects in close proximity to the fish.
In addition to information from sensory receptors, the ELL receives a signal from the area of the brain responsible for initiating the electrical discharges, known as the EOD command nucleus. This efference copy diverges, transmitted through two separate pathways, before the signals converge along with electrosensory input on Purkinje-like Medium Ganglion cells in the ELL. These cells receive information through extensive apical dendritic projections from parallel fibers that signal the transmission of an order to release an EOD. These cells also receive information from neurons conveying electrosensory information.
Important to anti-Hebbian learning, the synapses between the parallel fibers and the apical dendrites of Medium Ganglion cells show a specific pattern of synaptic plasticity. Should activation of the dendrites by parallel fibers occur in a short time period preceding the initiation of a dendritic broad spike (an action potential which travels through the dendrites), the strength of the co
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What are the contacts between neurons called?
A. synapses
B. impulses
C. neurapses
D. electrodes
Answer:
|
|
sciq-7354
|
multiple_choice
|
In hypothesis-based science, specific results are predicted from a general premise, which is called what type of reasoning that proceeds from general to particular?
|
[
"reactive",
"transitive",
"deductive",
"reflexive"
] |
C
|
Relavent Documents:
Document 0:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 1:::
In mathematical psychology and education theory, a knowledge space is a combinatorial structure used to formulate mathematical models describing the progression of a human learner. Knowledge spaces were introduced in 1985 by Jean-Paul Doignon and Jean-Claude Falmagne, and remain in extensive use in the education theory. Modern applications include two computerized tutoring systems, ALEKS and the defunct RATH.
Formally, a knowledge space assumes that a domain of knowledge is a collection of concepts or skills, each of which must be eventually mastered. Not all concepts are interchangeable; some require other concepts as prerequisites. Conversely, competency at one skill may ease the acquisition of another through similarity. A knowledge space marks out which collections of skills are feasible: they can be learned without mastering any other skills. Under reasonable assumptions, the collection of feasible competencies forms the mathematical structure known as an antimatroid.
Researchers and educators usually explore the structure of a discipline's knowledge space as a latent class model.
Motivation
Knowledge Space Theory attempts to address shortcomings of standardized testing when used in educational psychometry. Common tests, such as the SAT and ACT, compress a student's knowledge into a very small range of ordinal ranks, in the process effacing the conceptual dependencies between questions. Consequently, the tests cannot distinguish between true understanding and guesses, nor can they identify a student's particular weaknesses, only the general proportion of skills mastered. The goal of knowledge space theory is to provide a language by which exams can communicate
What the student can do and
What the student is ready to learn.
Model structure
Knowledge Space Theory-based models presume that an educational subject can be modeled as a finite set of concepts, skills, or topics. Each feasible state of knowledge about is then a subset of ; the set of
Document 2:::
Analytical skill is the ability to deconstruct information into smaller categories in order to draw conclusions. Analytical skill consists of categories that include logical reasoning, critical thinking, communication, research, data analysis and creativity. Analytical skill is taught in contemporary education with the intention of fostering the appropriate practises for future professions. The professions that adopt analytical skill include educational institutions, public institutions, community organisations and industry.
Richard J. Heuer Jr. explained that In the article by Freed, the need for programs within the educational system to help students develop these skills is demonstrated. Workers "will need more than elementary basic skills to maintain the standard of living of their parents. They will have to think for a living, analyse problems and solutions, and work cooperatively in teams".
Logical Reasoning
Logical reasoning is a process consisting of inferences, where premises and hypotheses are formulated to arrive at a probable conclusion. It is a broad term covering three sub-classifications in deductive reasoning, inductive reasoning and abductive reasoning.
Deductive Reasoning
‘Deductive reasoning is a basic form of valid reasoning, commencing with a general statement or hypothesis, then examines the possibilities to reach a specific, logical conclusion’. This scientific method utilises deductions, to test hypotheses and theories, to predict if possible observations were correct.
A logical deductive reasoning sequence can be executed by establishing: an assumption, followed by another assumption and finally, conducting an inference. For example, ‘All men are mortal. Harold is a man. Therefore, Harold is mortal.’
For deductive reasoning to be upheld, the hypothesis must be correct, therefore, reinforcing the notion that the conclusion is logical and true. It is possible for deductive reasoning conclusions to be inaccurate or incorrect entirely, bu
Document 3:::
Knowing and the Known is a 1949 book by John Dewey and Arthur Bentley.
Overview
As well as a Preface, an Introduction and an Index, the book consists of 12 chapters, or papers, as the authors call them in their introduction. Chapters 1 (Vagueness in Logic), 8 (Logic in an Age of Science) and 9 (A Confused "Semiotic") were written by Bentley; Chapter 10 (Common Sense and Science) by Dewey, while the remainder were signed jointly.
The terminology problem in the fields of epistemology and logic is partially due, according to Dewey and Bentley, to inefficient and imprecise use of words and concepts that reflect three historic levels of organization and presentation. In the order of chronological appearance, these are :
Self-Action: Prescientific concepts regarded humans, animals, and things as possessing powers of their own which initiated or caused their actions.
Interaction: as described by Newton, where things, living and inorganic, are balanced against something in a system of interaction, for example, the third law of motion states that for every action there is an equal and opposite reaction.
Transaction: where modern systems of descriptions and naming are employed to deal with multiple aspects and phases of action without any attribution to ultimate, final, or independent entities, essences, or realities.
Chapters
Vagueness in Logic
The Terminological Problem
Postulations
Interaction and Transaction
Transactions as Known and Named
Specification
The Case of Definition
Logic in an Age of Science
A Confused "Semiotic"
Common Sense and Science
A Trial Group of Names
Summary of Progress Made
Appendix: A Letter from John Dewey
Transactions
A series of characterizations of Transactions indicate the wide range of considerations involved.
Transaction is inquiry in which existing descriptions of events are accepted only as tentative and preliminary. New descriptions of the aspects and phases of events based on inquiry may be made at any time.
Transaction is inqu
Document 4:::
Discovery is the act of detecting something new, or something previously unrecognized as meaningful. Concerning sciences and academic disciplines, discovery is the observation of new phenomena, new actions, or new events and providing new reasoning to explain the knowledge gathered through such observations with previously acquired knowledge from abstract thought and everyday experiences. A discovery may sometimes be based on earlier discoveries, collaborations, or ideas. Some discoveries represent a radical breakthrough in knowledge or technology.
New discoveries are acquired through various senses and are usually assimilated, merging with pre-existing knowledge and actions. Questioning is a major form of human thought and interpersonal communication, and plays a key role in discovery. Discoveries are often made due to questions. Some discoveries lead to the invention of objects, processes, or techniques. A discovery may sometimes be based on earlier discoveries, collaborations or ideas, and the process of discovery requires at least the awareness that an existing concept or method can be modified or transformed. However, some discoveries also represent a radical breakthrough in knowledge.
Science
Within scientific disciplines, discovery is the observation of new phenomena, actions, or events which help explain the knowledge gathered through previously acquired scientific evidence. In science, exploration is one of three purposes of research, the other two being description and explanation. Discovery is made by providing observational evidence and attempts to develop an initial, rough understanding of some phenomenon.
Discovery within the field of particle physics has an accepted definition for what constitutes a discovery: a five-sigma level of certainty. Such a level defines statistically how unlikely it is that an experimental result is due to chance. The combination of a five-sigma level of certainty, and independent confirmation by other experiments, turn f
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
In hypothesis-based science, specific results are predicted from a general premise, which is called what type of reasoning that proceeds from general to particular?
A. reactive
B. transitive
C. deductive
D. reflexive
Answer:
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|
ai2_arc-163
|
multiple_choice
|
Tall plants are dominant to short plants. What is the outcome if two short plants are crossed?
|
[
"all tall plants",
"all short plants",
"half tall plants, half short plants",
"1/4 tall plants, 1/3 short plants"
] |
B
|
Relavent Documents:
Document 0:::
The SAT Subject Test in Biology was the name of a one-hour multiple choice test given on biology by the College Board. A student chose whether to take the test depending upon college entrance requirements for the schools in which the student is planning to apply. Until 1994, the SAT Subject Tests were known as Achievement Tests; and from 1995 until January 2005, they were known as SAT IIs. Of all SAT subject tests, the Biology E/M test was the only SAT II that allowed the test taker a choice between the ecological or molecular tests. A set of 60 questions was taken by all test takers for Biology and a choice of 20 questions was allowed between either the E or M tests. This test was graded on a scale between 200 and 800. The average for Molecular is 630 while Ecological is 591.
On January 19 2021, the College Board discontinued all SAT Subject tests, including the SAT Subject Test in Biology E/M. This was effective immediately in the United States, and the tests were to be phased out by the following summer for international students. This was done as a response to changes in college admissions due to the impact of the COVID-19 pandemic on education.
Format
This test had 80 multiple-choice questions that were to be answered in one hour. All questions had five answer choices. Students received one point for each correct answer, lost ¼ of a point for each incorrect answer, and received 0 points for questions left blank. The student's score was based entirely on his or her performance in answering the multiple-choice questions.
The questions covered a broad range of topics in general biology. There were more specific questions related respectively on ecological concepts (such as population studies and general Ecology) on the E test and molecular concepts such as DNA structure, translation, and biochemistry on the M test.
Preparation
The College Board suggested a year-long course in biology at the college preparatory level, as well as a one-year course in algebra, a
Document 1:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 2:::
Adaptive comparative judgement is a technique borrowed from psychophysics which is able to generate reliable results for educational assessment – as such it is an alternative to traditional exam script marking. In the approach, judges are presented with pairs of student work and are then asked to choose which is better, one or the other. By means of an iterative and adaptive algorithm, a scaled distribution of student work can then be obtained without reference to criteria.
Introduction
Traditional exam script marking began in Cambridge 1792 when, with undergraduate numbers rising, the importance of proper ranking of students was growing. So in 1792 the new Proctor of Examinations, William Farish, introduced marking, a process in which every examiner gives a numerical score to each response by every student, and the overall total mark puts the students in the final rank order. Francis Galton (1869) noted that, in an unidentified year about 1863, the Senior Wrangler scored 7,634 out of a maximum of 17,000, while the Second Wrangler scored 4,123. (The 'Wooden Spoon' scored only 237.)
Prior to 1792, a team of Cambridge examiners convened at 5pm on the last day of examining, reviewed the 19 papers each student had sat – and published their rank order at midnight. Marking solved the problems of numbers and prevented unfair personal bias, and its introduction was a step towards modern objective testing, the format it is best suited to. But the technology of testing that followed, with its major emphasis on reliability and the automatisation of marking, has been an uncomfortable partner for some areas of educational achievement: assessing writing or speaking, and other kinds of performance need something more qualitative and judgemental.
The technique of Adaptive Comparative Judgement is an alternative to marking. It returns to the pre-1792 idea of sorting papers according to their quality, but retains the guarantee of reliability and fairness. It is by far the most rel
Document 3:::
The Texas Math and Science Coaches Association or TMSCA is an organization for coaches of academic University Interscholastic League teams in Texas middle schools and high schools, specifically those that compete in mathematics and science-related tests.
Events
There are four events in the TMSCA at both the middle and high school level: Number Sense, General Mathematics, Calculator Applications, and General Science.
Number Sense is an 80-question exam that students are given only 10 minutes to solve. Additionally, no scratch work or paper calculations are allowed. These questions range from simple calculations such as 99+98 to more complicated operations such as 1001×1938. Each calculation is able to be done with a certain trick or shortcut that makes the calculations easier.
The high school exam includes calculus and other difficult topics in the questions also with the same rules applied as to the middle school version.
It is well known that the grading for this event is particularly stringent as errors such as writing over a line or crossing out potential answers are considered as incorrect answers.
General Mathematics is a 50-question exam that students are given only 40 minutes to solve. These problems are usually more challenging than questions on the Number Sense test, and the General Mathematics word problems take more thinking to figure out. Every problem correct is worth 5 points, and for every problem incorrect, 2 points are deducted. Tiebreakers are determined by the person that misses the first problem and by percent accuracy.
Calculator Applications is an 80-question exam that students are given only 30 minutes to solve. This test requires practice on the calculator, knowledge of a few crucial formulas, and much speed and intensity. Memorizing formulas, tips, and tricks will not be enough. In this event, plenty of practice is necessary in order to master the locations of the keys and develop the speed necessary. All correct questions are worth 5
Document 4:::
Single Best Answer (SBA or One Best Answer) is a written examination form of multiple choice questions used extensively in medical education.
Structure
A single question is posed with typically five alternate answers, from which the candidate must choose the best answer. This method avoids the problems of past examinations of a similar form described as Single Correct Answer. The older form can produce confusion where more than one of the possible answers has some validity. The newer form makes it explicit that more than one answer may have elements that are correct, but that one answer will be superior.
Prior to the widespread introduction of SBAs into medical education, the typical form of examination was true-false multiple choice questions. But during the 2000s, educators found that SBAs would be superior.
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Tall plants are dominant to short plants. What is the outcome if two short plants are crossed?
A. all tall plants
B. all short plants
C. half tall plants, half short plants
D. 1/4 tall plants, 1/3 short plants
Answer:
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|
sciq-7851
|
multiple_choice
|
When magma reaches the surface through cracks in the earth's crust, what occurs?
|
[
"tsunami",
"volcanic explosion",
"magma eruption",
"volcanic eruption"
] |
D
|
Relavent Documents:
Document 0:::
The rock cycle is a basic concept in geology that describes transitions through geologic time among the three main rock types: sedimentary, metamorphic, and igneous. Each rock type is altered when it is forced out of its equilibrium conditions. For example, an igneous rock such as basalt may break down and dissolve when exposed to the atmosphere, or melt as it is subducted under a continent. Due to the driving forces of the rock cycle, plate tectonics and the water cycle, rocks do not remain in equilibrium and change as they encounter new environments. The rock cycle explains how the three rock types are related to each other, and how processes change from one type to another over time. This cyclical aspect makes rock change a geologic cycle and, on planets containing life, a biogeochemical cycle.
Transition to igneous rock
When rocks are pushed deep under the Earth's surface, they may melt into magma. If the conditions no longer exist for the magma to stay in its liquid state, it cools and solidifies into an igneous rock. A rock that cools within the Earth is called intrusive or plutonic and cools very slowly, producing a coarse-grained texture such as the rock granite. As a result of volcanic activity, magma (which is called lava when it reaches Earth's surface) may cool very rapidly on the Earth's surface exposed to the atmosphere and are called extrusive or volcanic rocks. These rocks are fine-grained and sometimes cool so rapidly that no crystals can form and result in a natural glass, such as obsidian, however the most common fine-grained rock would be known as basalt. Any of the three main types of rocks (igneous, sedimentary, and metamorphic rocks) can melt into magma and cool into igneous rocks.
Secondary changes
Epigenetic change (secondary processes occurring at low temperatures and low pressures) may be arranged under a number of headings, each of which is typical of a group of rocks or rock-forming minerals, though usually more than one of these alt
Document 1:::
Earth's crustal evolution involves the formation, destruction and renewal of the rocky outer shell at that planet's surface.
The variation in composition within the Earth's crust is much greater than that of other terrestrial planets. Mars, Venus, Mercury and other planetary bodies have relatively quasi-uniform crusts unlike that of the Earth which contains both oceanic and continental plates. This unique property reflects the complex series of crustal processes that have taken place throughout the planet's history, including the ongoing process of plate tectonics.
The proposed mechanisms regarding Earth's crustal evolution take a theory-orientated approach. Fragmentary geologic evidence and observations provide the basis for hypothetical solutions to problems relating to the early Earth system. Therefore, a combination of these theories creates both a framework of current understanding and also a platform for future study.
Early crust
Mechanisms of early crust formation
The early Earth was entirely molten. This was due to high temperatures created and maintained by the following processes:
Compression of the early atmosphere
Rapid axial rotation
Regular impacts with neighbouring planetesimals.
The mantle remained hotter than modern day temperatures throughout the Archean. Over time the Earth began to cool as planetary accretion slowed and heat stored within the magma ocean was lost to space through radiation.
A theory for the initiation of magma solidification states that once cool enough, the cooler base of the magma ocean would begin to crystallise first. This is because pressure of 25 GPa at the surface cause the solidus to lower. The formation of a thin 'chill-crust' at the extreme surface would provide thermal insulation to the shallow sub surface, keeping it warm enough to maintain the mechanism of crystallisation from the deep magma ocean.
The composition of the crystals produced during the crystallisation of the magma ocean varied with depth. Ex
Document 2:::
A gas slug is a conglomerate of high pressure gas bubbles that forms within certain volcanoes, the agitation of which is a key driving factor in Strombolian eruptions. They start out as small bubbles of gas inside of volcanic magma.These accumulate into one large bubble, which starts to rise through the lava plume.
Volcanic eruptions consist of mostly water vapor gases, with sulfur dioxide and carbon dioxide playing a huge part in gas release as well. Once the accumulated slug reaches the top of the column and comes in contact with air, it bursts with a loud pop because of the lower air pressure, throwing magma into the air in the typical lava volcanic arc of a Strombolian eruption. This type of eruption is episodic, non-damaging to its source vent, and one of the slowest forms of activity, with the ability to sustain itself for thousands of years.
Although the effect of gas slugs in lava is well understood, how they form is not well understood, but recent research suggests that they can form as deep as under the surface.
Document 3:::
Maui Nui is a modern geologists' name given to a prehistoric Hawaiian island and the corresponding modern biogeographic region. Maui Nui is composed of four modern islands: Maui, Molokaʻi, Lānaʻi, and Kahoʻolawe. Administratively, the four modern islands comprise Maui County (and a tiny part of Molokaʻi called Kalawao County). Long after the breakup of Maui Nui, the four modern islands retained plant and animal life similar to each other. Thus, Maui Nui is not only a prehistoric island but also a modern biogeographic region.
Geology
Maui Nui formed and broke up during the Pleistocene Epoch, which lasted from about 2.58 million to 11,700 years ago.
Maui Nui is built from seven shield volcanoes. The three oldest are Penguin Bank, West Molokaʻi, and East Molokaʻi, which probably range from slightly over to slightly less than 2 million years old. The four younger volcanoes are Lāna‘i, West Maui, Kaho‘olawe, and Haleakalā, which probably formed between 1.5 and 2 million years ago.
At its prime 1.2 million years ago, Maui Nui was , 50% larger than today's Hawaiʻi Island. The island of Maui Nui included four modern islands (Maui, Molokaʻi, Lānaʻi, and Kahoʻolawe) and landmass west of Molokaʻi called Penguin Bank, which is now completely submerged.
Maui Nui broke up as rising sea levels flooded the connections between the volcanoes. The breakup was complex because global sea levels rose and fell intermittently during the Quaternary glaciation. About 600,000 years ago, the connection between Molokaʻi and the island of Lāna‘i/Maui/Kahoʻolawe became intermittent. About 400,000 years ago, the connection between Lāna‘i and Maui/Kahoʻolawe also became intermittent. The connection between Maui and Kahoʻolawe was permanently broken between 200,000 and 150,000 years ago. Maui, Lāna‘i, and Molokaʻi were connected intermittently thereafter, most recently about 18,000 years ago during the Last Glacial Maximum.
Today, the sea floor between these four islands is relatively shallow
Document 4:::
Dallol is a unique, terrestrial hydrothermal system around a cinder cone volcano in the Danakil Depression, northeast of the Erta Ale Range in Ethiopia. It is known for its unearthly colors and mineral patterns, and the very acidic fluids that discharge from its hydrothermal springs.
Etymology
The term Dallol was coined by the Afar people and means dissolution or disintegration, describing a landscape of green acid ponds and geysers (pH-values less than 1) and iron oxide, sulfur and salt desert plains. The area somewhat resembles the hot springs areas of Yellowstone National Park.
Description
Dallol mountain has an area of about , and rises about above the surrounding salt plains. A circular depression near the centre is probably a collapsed crater. The southwestern slopes have water-eroded salt canyons, pillars, and blocks. There are numerous saline springs and fields of small fumaroles.
Numerous hot springs discharge brine and acidic liquid here. Small, widespread, temporary geysers produce cones of salt. The Dallol deposits include significant bodies of potash found directly at the surface. The yellow, ochre and brown colourings are the result of the presence of iron and other impurities. Older, inactive springs tend to be dark brown because of oxidation processes.
Formation
It was formed by the intrusion of basaltic magma into Miocene salt deposits and subsequent hydrothermal activity. Phreatic eruptions took place here in 1926, forming Dallol Volcano; numerous other eruption craters dot the salt flats nearby. These craters are the lowest known subaerial volcanic vents in the world, at or more below sea level. In October 2004 the shallow magma chamber beneath Dallol deflated and fed a magma intrusion southwards beneath the rift. The most recent signs of activity occurred in January 2011 in what may have been a degassing event from deep below the surface.
Physical properties
Dallol lies in the evaporitic plain of the Danakil Depression at the Afar Triangle
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
When magma reaches the surface through cracks in the earth's crust, what occurs?
A. tsunami
B. volcanic explosion
C. magma eruption
D. volcanic eruption
Answer:
|
|
sciq-2389
|
multiple_choice
|
What is crucial for the fermentation progress in making bread?
|
[
"larvae",
"cold",
"yeast",
"fruit"
] |
C
|
Relavent Documents:
Document 0:::
A ferment (also known as bread starter) is a fermentation starter used in indirect methods of bread making. It may also be called mother dough.
A ferment and a longer fermentation in the bread-making process have several benefits: there is more time for yeast, enzyme and, if sourdough, bacterial actions on the starch and proteins in the dough; this in turn improves the keeping time of the baked bread, and it creates greater complexities of flavor. Though ferments have declined in popularity as direct additions of yeast in bread recipes have streamlined the process on a commercial level, ferments of various forms are widely used in artisanal bread recipes and formulas.
Classifications
In general, there are two ferment varieties: sponges, based on baker's yeast, and the starters of sourdough, based on wild yeasts and lactic acid bacteria. There are several kinds of pre-ferment commonly named and used in bread baking. They all fall on a varying process and time spectrum, from a mature mother dough of many generations of age to a first-generation sponge based on a fresh batch of baker's yeast:
Biga and poolish (or pouliche) are terms used in Italian and French baking, respectively, for sponges made with domestic baker's yeast. Poolish is a fairly wet sponge (typically one-to-one, this is made with a one-part-flour-to-one-part-water ratio by weight), and it is called biga liquida, whereas the "normal" biga is usually drier. Bigas can be held longer at their peak than wetter sponges, while a poolish is one known technique to increase a dough's extensibility.
Sourdough starter is likely the oldest, being reliant on organisms present in the grain and local environment. In general, these starters have fairly complex microbiological makeups, the most notable including wild yeasts, lactobacillus, and acetobacteria in symbiotic relationship referred to as a SCOBY. They are often maintained over long periods of time. For example, the Boudin Bakery in San Francisco has used t
Document 1:::
In food processing, fermentation is the conversion of carbohydrates to alcohol or organic acids using microorganisms—yeasts or bacteria—under anaerobic (oxygen-free) conditions. Fermentation usually implies that the action of microorganisms is desired. The science of fermentation is known as zymology or zymurgy.
The term "fermentation" sometimes refers specifically to the chemical conversion of sugars into ethanol, producing alcoholic drinks such as wine, beer, and cider. However, similar processes take place in the leavening of bread (CO2 produced by yeast activity), and in the preservation of sour foods with the production of lactic acid, such as in sauerkraut and yogurt.
Other widely consumed fermented foods include vinegar, olives, and cheese. More localised foods prepared by fermentation may also be based on beans, grain, vegetables, fruit, honey, dairy products, and fish.
History and prehistory
Brewing and winemaking
Natural fermentation precedes human history. Since ancient times, humans have exploited the fermentation process. The earliest archaeological evidence of fermentation is 13,000-year-old residues of a beer, with the consistency of gruel, found in a cave near Haifa in Israel. Another early alcoholic drink, made from fruit, rice, and honey, dates from 7000 to 6600 BC, in the Neolithic Chinese village of Jiahu, and winemaking dates from ca. 6000 BC, in Georgia, in the Caucasus area. Seven-thousand-year-old jars containing the remains of wine, now on display at the University of Pennsylvania, were excavated in the Zagros Mountains in Iran. There is strong evidence that people were fermenting alcoholic drinks in Babylon ca. 3000 BC, ancient Egypt ca. 3150 BC, pre-Hispanic Mexico ca. 2000 BC, and Sudan ca. 1500 BC.
Discovery of the role of yeast
The French chemist Louis Pasteur founded zymology, when in 1856 he connected yeast to fermentation.
When studying the fermentation of sugar to alcohol by yeast, Pasteur concluded that the fermentation wa
Document 2:::
Microbial food cultures are live bacteria, yeasts or moulds used in food production. Microbial food cultures carry out the fermentation process in foodstuffs. Used by humans since the Neolithic period (around 10 000 years BC) fermentation helps to preserve perishable foods and to improve their nutritional and organoleptic qualities (in this case, taste, sight, smell, touch). As of 1995, fermented food represented between one quarter and one third of food consumed in Central Europe. More than 260 different species of microbial food culture are identified and described for their beneficial use in fermented food products globally, showing the importance of their use.
The scientific rationale of the function of microbes in fermentation started to be built with the discoveries of Louis Pasteur in the second half of the 19th century. Extensive scientific study continues to characterize microbial food cultures traditionally used in food fermentation taxonomically, physiologically, biochemically and genetically. This allows better understanding and improvement of traditional food processing and opens up new fields of applications.
Historical overview
Microorganisms are the earliest form of life on earth, first evolving more than three billion years ago. Our ancestors discovered how to harness the power of microorganisms to make new foods, even if they did not know the science behind what they were doing.
Milestones
1665—Robert Hooke and Antoni Van Leeuwenhoek first observe and describe microorganisms.
1857–1876—Louis Pasteur proves the function of microorganisms in lactic and alcoholic fermentation.
1881—Emil Christian Hansen isolates Saccharomyces carlsbergensis, a pure yeast culture, which is today widely used in brewing of lager beers.
1889–1896—Herbert William Conn, Vilhelm Storch and Hermann Weigmann demonstrate that bacteria are responsible for the acidification of milk and of cream.
1897—Eduard von Freudenreich isolates Lactobacillus brevis.
1919—Sigurd O
Document 3:::
The branches of microbiology can be classified into pure and applied sciences. Microbiology can be also classified based on taxonomy, in the cases of bacteriology, mycology, protozoology, and phycology. There is considerable overlap between the specific branches of microbiology with each other and with other disciplines, and certain aspects of these branches can extend beyond the traditional scope of microbiology
In general the field of microbiology can be divided in the more fundamental branch (pure microbiology) and the applied microbiology (biotechnology). In the more fundamental field the organisms are studied as the subject itself on a deeper (theoretical) level.
Applied microbiology refers to the fields where the micro-organisms are applied in certain processes such as brewing or fermentation. The organisms itself are often not studied as such, but applied to sustain certain processes.
Pure microbiology
Bacteriology: the study of bacteria
Mycology: the study of fungi
Protozoology: the study of protozoa
Phycology/algology: the study of algae
Parasitology: the study of parasites
Immunology: the study of the immune system
Virology: the study of viruses
Nematology: the study of nematodes
Microbial cytology: the study of microscopic and submicroscopic details of microorganisms
Microbial physiology: the study of how the microbial cell functions biochemically. Includes the study of microbial growth, microbial metabolism and microbial cell structure
Microbial pathogenesis: the study of pathogens which happen to be microbes
Microbial ecology: the relationship between microorganisms and their environment
Microbial genetics: the study of how genes are organized and regulated in microbes in relation to their cellular functions Closely related to the field of molecular biology
Cellular microbiology: a discipline bridging microbiology and cell biology
Evolutionary microbiology: the study of the evolution of microbes. This field can be subdivided into:
Micr
Document 4:::
Solid state fermentation (SSF) is a biomolecule manufacturing process used in the food, pharmaceutical, cosmetic, fuel and textile industries. These biomolecules are mostly metabolites generated by microorganisms grown on a solid support selected for this purpose. This technology for the culture of microorganisms is an alternative to liquid or submerged fermentation, used predominantly for industrial purposes.
Processes
This process consists of depositing a solid culture substrate, such as rice or wheat bran, on flatbeds after seeding it with microorganisms; the substrate is then left in a temperature-controlled room for several days.
Liquid state fermentation is performed in tanks, which can reach at an industrial scale. Liquid culture is ideal for the growing of unicellular organisms such as bacteria or yeasts.
To achieve liquid aerobic fermentation, it is necessary to constantly supply the microorganism with oxygen, which is generally done via stirring the fermentation media. Accurately managing the synthesis of the desired metabolites requires regulating temperature, soluble oxygen, ionic strength and pH and control nutrients.
Applying this growing technique to filamentous fungi leads to difficulties. The fungus develops in its vegetative form, generating hyphae or multicellular ramous filaments, while a septum separates the cells. As this mycelium develops in a liquid environment, it generates abundant viscosity in the growing medium, reducing oxygen solubility, while stirring disrupts the cell network increasing cell mortality.
In nature, filamentous fungi grow on the ground, decomposing vegetal compounds under naturally ventilated conditions. Therefore, solid state fermentation enables the optimal development of filamentous fungi, allowing the mycelium to spread on the surface of solid compounds among which air can flow.
Solid state fermentation uses culture substrates with low water levels (reduced water activity), which is particularly appropriate fo
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What is crucial for the fermentation progress in making bread?
A. larvae
B. cold
C. yeast
D. fruit
Answer:
|
|
sciq-10160
|
multiple_choice
|
How are protozoa that cause giardiasis spread?
|
[
"insects",
"starch and water",
"food and water",
"lakes and rivers"
] |
C
|
Relavent Documents:
Document 0:::
Microbes and Man is a popularising book by the English microbiologist John Postgate FRS on the role of microorganisms in human society, first published in 1969, and still in print in 2017. Critics called it a "classic" and "a pleasure to read".
Book
Contents
The book is structured as follows:
1 Man and microbes
2 Microbiology
3 Microbes in society
4 Interlude: how to handle microbes
5 Microbes in nutrition
6 Microbes in production
7 Deterioration, decay and pollution
8 Disposal and cleaning-up
9 Second interlude: microbiologists and man
10 Microbes in evolution
11 Microbes in the future
Illustrations
The 4th edition has 32 illustrations, ranging from photographs of microscopic algae, protozoa, fungi, viruses and bacteria, to the macroscopic effects of microbes such as a sulphur-forming lake in Libya and fish killed by bacterial reduction of sulphate in water.
Editions
1st edition, Cambridge University Press, 1969
2nd edition, Cambridge University Press, 1986
3rd edition, Cambridge University Press, 1992
4th edition, Cambridge University Press, 2000
The book has been translated into nine languages: Arabic, Chinese, Czech, French, German, Japanese, Polish, Portuguese, and Spanish.
Reception
The Guardian described the book as "a passionate case for the importance of micro-organisms".
In his textbook Essential Microbiology, Stuart Hogg recommends the book to readers who want a general overview of microbes and their uses, stating "there can be no better starting point than John Postgate's classic".
New Scientist described the book as "a pleasure to read from first page to last. It is a literal statement. Start to read it and the first page, describing the astonishing dispersion of microbes, from the upper atmosphere to the depths of the sea, will provide any reader with enough wonder and excitement to take them through to the last page and the surface of Venus." The magazine commented that Postgate's "admirable, elegantly written and painlessl
Document 1:::
Germ theory denialism is the pseudoscientific belief that germs do not cause infectious disease, and that the germ theory of disease is wrong. It usually involves arguing that Louis Pasteur's model of infectious disease was wrong, and that Antoine Béchamp's was right. In fact, its origins are rooted in Béchamp's empirically disproven (in the context of disease) theory of pleomorphism. Another obsolete variation is known as terrain theory and postulates that the state of the internal environment determines if germs cause disease rather than germs being the sole cause of it.
History
Germ theory denialism (GTD) is as old as germ theory itself, beginning with the rivalry of Pasteur and Béchamp. Pasteur's work in preventing beverage contamination led him to discover that it was due to microorganisms and led him to become the first scientist to prove the validity of the theory and to popularize it in Europe. Before him, scientists such as Girolamo Fracastoro (who had the idea that fomites could harbor the seeds of contagion), Agostino Bassi (who discovered that the muscardine disease of silkworms was caused by a fungus that was named Beauveria bassiana), Friedrich Henle (who developed the concepts of contagium vivum and contagium animatum), and others had proposed ideas similar to germ theory.
Béchamp strongly contested Pasteur's view, proposing a competing idea known as the pleomorphic theory of disease. This theory says that all life is based on forms that a certain class of organisms take during stages of their life cycles and that germs are attracted to the environment of diseased tissue rather than being the cause of it. Proponents of this idea insist that microbes that live in an organism go through the same stages of their development. According to Günther Enderlein, the stages are as follows:
colloid – microbe (primitive phase)
bacteria (middle phase)
fungus (end phase)
Terrain theory
The terrain theory is a variation of Béchamp's ideas that is also an
Document 2:::
Bacteriology is the branch and specialty of biology that studies the morphology, ecology, genetics and biochemistry of bacteria as well as many other aspects related to them. This subdivision of microbiology involves the identification, classification, and characterization of bacterial species. Because of the similarity of thinking and working with microorganisms other than bacteria, such as protozoa, fungi, and viruses, there has been a tendency for the field of bacteriology to extend as microbiology. The terms were formerly often used interchangeably. However, bacteriology can be classified as a distinct science.
Overview
Definition
Bacteriology is the study of bacteria and their relation to medicine. Bacteriology evolved from physicians needing to apply the germ theory to address the concerns relating to disease spreading in hospitals the 19th century. Identification and characterizing of bacteria being associated to diseases led to advances in pathogenic bacteriology. Koch's postulates played a role into identifying the relationships between bacteria and specific diseases. Since then, bacteriology has played a role in successful advances in science such as bacterial vaccines like diphtheria toxoid and tetanus toxoid. Bacteriology can be studied and applied in many sub-fields relating to agriculture, marine biology, water pollution, bacterial genetics, veterinary medicine, biotechnology and others.
Bacteriologists
A bacteriologist is a microbiologist or other trained professional in bacteriology. Bacteriologists are interested in studying and learning about bacteria, as well as using their skills in clinical settings. This includes investigating properties of bacteria such as morphology, ecology, genetics and biochemistry, phylogenetics, genomics and many other areas related to bacteria like disease diagnostic testing. They can also work as medical scientists, veterinary scientists, or diagnostic technicians in locations like clinics, blood banks, hospitals
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Yersinia enterocolitica is a Gram-negative, rod-shaped bacterium, belonging to the family Yersiniaceae. It is motile at temperatures of 22–29°C (72–84°F), but becomes nonmotile at normal human body temperature. Y. enterocolitica infection causes the disease yersiniosis, which is an animal-borne disease occurring in humans, as well as in a wide array of animals such as cattle, deer, pigs, and birds. Many of these animals recover from the disease and become carriers; these are potential sources of contagion despite showing no signs of disease. The bacterium infects the host by sticking to its cells using trimeric autotransporter adhesins.
The genus Yersinia includes 20 species: Y. aldovae, Y. aleksiciae, Y. bercovieri, Y. canariae, Y. enterocolitica, Y. entomophaga, Y. frederiksenii, Y. hibernica, Y. intermedia, Y. kristensenii, Y. massiliensis, Y. mollaretii, Y. nurmii, Y. pekkanenii, Y. pestis, Y. pseudotuberculosis, Y. rohdei, Y. ruckeri, Y. similis, and Y. wautersii. Among them, only Y. pestis, Y. pseudotuberculosis, and certain strains of Y. enterocolitica are of pathogenic importance for humans and certain warm-blooded animals, whereas the other species are of environmental origin and may, at best, act as opportunists. However, Yersinia strains can be isolated from clinical materials, so they have to be identified at the species level.
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When considering pathogens, host adaptation can have varying descriptions. For example, in the case of Salmonella, host adaptation is used to describe the "ability of a pathogen to circulate and cause disease in a particular host population." Another usage of host adaptation, still considering the case of Salmonella, refers to the evolution of a pathogen such that it can infect, cause disease, and circulate in another host species.
Description
While there might be pathogens that can infect other hosts and cause disease, the inability to pervade, or spread, throughout the infected host species indicates that the pathogen is not adapted to that host species. In this case, the ability or lack thereof of a pathogen to adapt to its host environment is an indicator of the pathogen's fitness or virulence. If a pathogen has high fitness in the host environment, or is virulent, it will be able to grow and spread quickly within its host. Conversely, if the pathogen is not well adapted to its host environment, then it will not spread or infect the way a well adapted pathogen would.
Pathogens like Salmonella, which is a food borne pathogen, are able to adapt to the host environment and maintain virulence via several pathways. In a paper by Baumler et al. 1998, characters of Salmonella, such as its ability to cause intestinal infection were attributed to virulence factors like its ability to invade intestinal epithelial cells, induce neutrophil recruitment and interfere with the secretion of intestinal fluid. Phylogenetic analysis also revealed that many strains or lineages of Salmonella exist, which is advantageous for the pathogen because its genetic diversity can acts as fodder for natural selection to tinder with. For instance, if a particular Salmonella strain is more fit in the host stomach environment, compared to other Salmonella strains, then the former will be positively selected for and increase in prevalence. Eventually this strain will colonize and infect the st
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
How are protozoa that cause giardiasis spread?
A. insects
B. starch and water
C. food and water
D. lakes and rivers
Answer:
|
|
sciq-10848
|
multiple_choice
|
Where does an electron move to after it absorbs energy?
|
[
"a shell farther from the nucleus",
"atomic orbit",
"another electron",
"a shell closer to the nucleus"
] |
A
|
Relavent Documents:
Document 0:::
Secondary electrons are electrons generated as ionization products. They are called 'secondary' because they are generated by other radiation (the primary radiation). This radiation can be in the form of ions, electrons, or photons with sufficiently high energy, i.e. exceeding the ionization potential. Photoelectrons can be considered an example of secondary electrons where the primary radiation are photons; in some discussions photoelectrons with higher energy (>50 eV) are still considered "primary" while the electrons freed by the photoelectrons are "secondary".
Applications
Secondary electrons are also the main means of viewing images in the scanning electron microscope (SEM). The range of secondary electrons depends on the energy. Plotting the inelastic mean free path as a function of energy often shows characteristics of the "universal curve" familiar to electron spectroscopists and surface analysts. This distance is on the order of a few nanometers in metals and tens of nanometers in insulators. This small distance allows such fine resolution to be achieved in the SEM.
For SiO2, for a primary electron energy of 100 eV, the secondary electron range is up to 20 nm from the point of incidence.
See also
Delta ray
Everhart-Thornley detector
Document 1:::
A fixed orbit is the concept, in atomic physics, where an electron is considered to remain in a specific orbit, at a fixed distance from an atom's nucleus, for a particular energy level.
The concept was promoted by quantum physicist Niels Bohr c. 1913.
The idea of the fixed orbit is considered a major component of the Bohr model (or Bohr theory).
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A quantum mechanical system or particle that is bound—that is, confined spatially—can only take on certain discrete values of energy, called energy levels. This contrasts with classical particles, which can have any amount of energy. The term is commonly used for the energy levels of the electrons in atoms, ions, or molecules, which are bound by the electric field of the nucleus, but can also refer to energy levels of nuclei or vibrational or rotational energy levels in molecules. The energy spectrum of a system with such discrete energy levels is said to be quantized.
In chemistry and atomic physics, an electron shell, or principal energy level, may be thought of as the orbit of one or more electrons around an atom's nucleus. The closest shell to the nucleus is called the " shell" (also called "K shell"), followed by the " shell" (or "L shell"), then the " shell" (or "M shell"), and so on farther and farther from the nucleus. The shells correspond with the principal quantum numbers (n = 1, 2, 3, 4 ...) or are labeled alphabetically with letters used in the X-ray notation (K, L, M, N...).
Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2n2 electrons. Since electrons are electrically attracted to the nucleus, an atom's electrons will generally occupy outer shells only if the more inner shells have already been completely filled by other electrons. However, this is not a strict requirement: atoms may have two or even three incomplete outer shells. (See Madelung rule for more details.) For an explanation of why electrons exist in these shells see electron configuration.
If the potential energy is set to zero at infinite distance from the atomic nucleus or molecule, the usual convention, then bound electron states have negative pot
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Photoinduced charge separation is the process of an electron in an atom or molecule, being excited to a higher energy level by the absorption of a photon and then leaving the atom or molecule to free space, or to a nearby electron acceptor.
Rutherford model
An atom consists of a positively-charged nucleus surrounded by bound electrons. The nucleus consists of uncharged neutrons and positively charged protons. Electrons are negatively charged. In the early part of the twentieth century Ernest Rutherford suggested that the electrons orbited the dense central nucleus in a manner analogous to planets orbiting the Sun. The centripetal force required to keep the electrons in orbit was provided by the Coulomb force of the protons in the nucleus acting upon the electrons; just like the gravitational force of the Sun acting on a planet provides the centripetal force necessary to keep the planet in orbit.
This model, although appealing, doesn't hold true in the real world. Synchrotron radiation would cause the orbiting electron to lose orbital energy and spiral inward since the vector quantity of acceleration of the particle multiplied by its mass (the value of the force required to keep the electron in circular motion) would be less than the electrical force the proton applied to the electron.
Once the electron spiralled into the nucleus the electron would combine with a proton to form a neutron, and the atom would cease to exist. This model is clearly wrong.
Bohr model
In 1913, Niels Bohr refined the Rutherford model by stating that the electrons existed in discrete quantized states called energy levels. This meant that the electrons could only occupy orbits at certain energies. The laws of quantum physics apply here, and they don't comply with the laws of classical newtonian mechanics.
An electron which is stationary and completely free from the atom has an energy of 0 joules (or 0 electronvolts). An electron which is described as being at the "ground state" has a (ne
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In chemistry and atomic physics, an electron shell may be thought of as an orbit that electrons follow around an atom's nucleus. The closest shell to the nucleus is called the "1 shell" (also called the "K shell"), followed by the "2 shell" (or "L shell"), then the "3 shell" (or "M shell"), and so on farther and farther from the nucleus. The shells correspond to the principal quantum numbers (n = 1, 2, 3, 4 ...) or are labeled alphabetically with the letters used in X-ray notation (K, L, M, ...). A useful guide when understanding electron shells in atoms is to note that each row on the conventional periodic table of elements represents an electron shell.
Each shell can contain only a fixed number of electrons: the first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2(n2) electrons. For an explanation of why electrons exist in these shells, see electron configuration.
Each shell consists of one or more subshells, and each subshell consists of one or more atomic orbitals.
History
In 1913 Bohr proposed a model of the atom, giving the arrangement of electrons in their sequential orbits. At that time, Bohr allowed the capacity of the inner orbit of the atom to increase to eight electrons as the atoms got larger, and "in the scheme given below the number of electrons in this [outer] ring is arbitrary put equal to the normal valency of the corresponding element." Using these and other constraints, he proposed configurations that are in accord with those now known only for the first six elements. "From the above we are led to the following possible scheme for the arrangement of the electrons in light atoms:"
The shell terminology comes from Arnold Sommerfeld's modification of the 1913 Bohr model. During this period Bohr was working with Walther Kossel, whose papers in 1914 and in 1916 called the or
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Where does an electron move to after it absorbs energy?
A. a shell farther from the nucleus
B. atomic orbit
C. another electron
D. a shell closer to the nucleus
Answer:
|
|
sciq-225
|
multiple_choice
|
Where does the embryo develop in a plant?
|
[
"outside the female plant after fertilization",
"inside the stem after fertilization",
"inside the male plant after fertilization",
"inside the female plant after fertilization"
] |
D
|
Relavent Documents:
Document 0:::
Plant embryonic development, also plant embryogenesis is a process that occurs after the fertilization of an ovule to produce a fully developed plant embryo. This is a pertinent stage in the plant life cycle that is followed by dormancy and germination. The zygote produced after fertilization must undergo various cellular divisions and differentiations to become a mature embryo. An end stage embryo has five major components including the shoot apical meristem, hypocotyl, root meristem, root cap, and cotyledons. Unlike the embryonic development in animals, and specifically in humans, plant embryonic development results in an immature form of the plant, lacking most structures like leaves, stems, and reproductive structures. However, both plants and animals including humans, pass through a phylotypic stage that evolved independently and that causes a developmental constraint limiting morphological diversification.
Morphogenic events
Embryogenesis occurs naturally as a result of single, or double fertilization, of the ovule, giving rise to two distinct structures: the plant embryo and the endosperm which go on to develop into a seed. The zygote goes through various cellular differentiations and divisions in order to produce a mature embryo. These morphogenic events form the basic cellular pattern for the development of the shoot-root body and the primary tissue layers; it also programs the regions of meristematic tissue formation. The following morphogenic events are only particular to eudicots, and not monocots.
Plant
Following fertilization, the zygote and endosperm are present within the ovule, as seen in stage I of the illustration on this page. Then the zygote undergoes an asymmetric transverse cell division that gives rise to two cells - a small apical cell resting above a large basal cell.
These two cells are very different, and give rise to different structures, establishing polarity in the embryo.
apical cellThe small apical cell is on the top and contains
Document 1:::
Important structures in plant development are buds, shoots, roots, leaves, and flowers; plants produce these tissues and structures throughout their life from meristems located at the tips of organs, or between mature tissues. Thus, a living plant always has embryonic tissues. By contrast, an animal embryo will very early produce all of the body parts that it will ever have in its life. When the animal is born (or hatches from its egg), it has all its body parts and from that point will only grow larger and more mature. However, both plants and animals pass through a phylotypic stage that evolved independently and that causes a developmental constraint limiting morphological diversification.
According to plant physiologist A. Carl Leopold, the properties of organization seen in a plant are emergent properties which are more than the sum of the individual parts. "The assembly of these tissues and functions into an integrated multicellular organism yields not only the characteristics of the separate parts and processes but also quite a new set of characteristics which would not have been predictable on the basis of examination of the separate parts."
Growth
A vascular plant begins from a single celled zygote, formed by fertilisation of an egg cell by a sperm cell. From that point, it begins to divide to form a plant embryo through the process of embryogenesis. As this happens, the resulting cells will organize so that one end becomes the first root while the other end forms the tip of the shoot. In seed plants, the embryo will develop one or more "seed leaves" (cotyledons). By the end of embryogenesis, the young plant will have all the parts necessary to begin in its life.
Once the embryo germinates from its seed or parent plant, it begins to produce additional organs (leaves, stems, and roots) through the process of organogenesis. New roots grow from root meristems located at the tip of the root, and new stems and leaves grow from shoot meristems located at the
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The quiescent centre is a group of cells, up to 1,000 in number, in the form of a hemisphere, with the flat face toward the root tip of vascular plants. It is a region in the apical meristem of a root where cell division proceeds very slowly or not at all, but the cells are capable of resuming meristematic activity when the tissue surrounding them is damaged.
Cells of root apical meristems do not all divide at the same rate. Determinations of relative rates of DNA synthesis show that primary roots of Zea, Vicia and Allium have quiescent centres to the meristems, in which the cells divide rarely or never in the course of normal root growth (Clowes, 1958). Such a quiescent centre includes the cells at the apices of the histogens of both stele and cortex. Its presence can be deduced from the anatomy of the apex in Zea (Clowes, 1958), but not in the other species which lack discrete histogens.
History
In 1953, during the course of analysing the organization and function of the root apices, Frederick Albert Lionel Clowes (born 10 September 1921), at the School of Botany (now Department of Plant Sciences), University of Oxford, proposed the term ‘cytogenerative centre’ to denote ‘the region of an apical meristem from which all future cells are derived’. This term had been suggested to him by Mr Harold K. Pusey, a lecturer in embryology at the Department of Zoology and Comparative Anatomy at the same university. The 1953 paper of Clowes reported results of his experiments on Fagus sylvatica and Vicia faba, in which small oblique and wedge-shaped excisions were made at the tip of the primary root, at the most distal level of the root body, near the boundary with the root cap. The results of these experiments were striking and showed that: the root which grew on following the excision was normal at the undamaged meristem side; the nonexcised meristem portion contributed to the regeneration of the excised portion; the regenerated part of the root had abnormal patterning and
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Somatic embryogenesis is an artificial process in which a plant or embryo is derived from a single somatic cell. Somatic embryos are formed from plant cells that are not normally involved in the development of embryos, i.e. ordinary plant tissue. No endosperm or seed coat is formed around a somatic embryo.
Cells derived from competent source tissue are cultured to form an undifferentiated mass of cells called a callus. Plant growth regulators in the tissue culture medium can be manipulated to induce callus formation and subsequently changed to induce embryos to form the callus. The ratio of different plant growth regulators required to induce callus or embryo formation varies with the type of plant. Somatic embryos are mainly produced in vitro and for laboratory purposes, using either solid or liquid nutrient media which contain plant growth regulators (PGR’s). The main PGRs used are auxins but can contain cytokinin in a smaller amount. Shoots and roots are monopolar while somatic embryos are bipolar, allowing them to form a whole plant without culturing on multiple media types. Somatic embryogenesis has served as a model to understand the physiological and biochemical events that occur during plant developmental processes as well as a component to biotechnological advancement. The first documentation of somatic embryogenesis was by Steward et al. in 1958 and Reinert in 1959 with carrot cell suspension cultures.
Direct and indirect embryogenesis
Somatic embryogenesis has been described to occur in two ways: directly or indirectly.
Direct embryogenesis
occurs when embryos are started directly from explant tissue creating an identical clone. In other words without callus formation of embryo from explant, that is called direct embryogenesis.
Indirect embryogenesis
occurs when explants produced undifferentiated, or partially differentiated, cells (often referred to as callus) which then is maintained or differentiated into plant tissues such as leaf, stem, or root
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In plant science, the spermosphere is the zone in the soil surrounding a germinating seed. This is a small volume with radius perhaps 1 cm but varying with seed type, the variety of soil microorganisms, the level of soil moisture, and other factors. Within the spermosphere a range of complex interactions take place among the germinating seed, the soil, and the microbiome. Because germination is a brief process, the spermosphere is transient, but the impact of the microbial activity within the spermosphere can have strong and long-lasting effects on the developing plant.
Seeds exude various molecules that influence their surrounding microbial communities, either inhibiting or stimulating their growth. The composition of the exudates varies according to the plant type and such properties of the soil as its pH and moisture content. With these biochemical effects, the spermosphere develops both downward—to form the rhizosphere (upon the emergence of the plant's radicle)—and upward to form the laimosphere, which is the soil surrounding the growing plant stem.
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Where does the embryo develop in a plant?
A. outside the female plant after fertilization
B. inside the stem after fertilization
C. inside the male plant after fertilization
D. inside the female plant after fertilization
Answer:
|
|
ai2_arc-63
|
multiple_choice
|
Which of these is an example of liquid water?
|
[
"Frost",
"Ice",
"Rain",
"Steam"
] |
C
|
Relavent Documents:
Document 0:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 1:::
Binary liquid is a type of chemical combination, which creates a special reaction or feature as a result of mixing two liquid chemicals, that are normally inert or have no function by themselves. A number of chemical products are produced as a result of mixing two chemicals as a binary liquid, such as plastic foams and some explosives.
See also
Binary chemical weapon
Thermophoresis
Percus-Yevick equation
Document 2:::
Liquid 3 is an urban photobioreactor tank full of water and micro-algae installed as way to produce oxygen in cities that have high in the air. They also have sitting benches and solar energy panel next to them and can be used to fill urban pockets.
They may replace function of an adult tree. They have been used in Serbian cities, such as Belgrade. They are developed through UNDP. It contains 600 liters (159 gallons) of water and works by photosynthesis.
Document 3:::
At equilibrium, the relationship between water content and equilibrium relative humidity of a material can be displayed graphically by a curve, the so-called moisture sorption isotherm.
For each humidity value, a sorption isotherm indicates the corresponding water content value at a given, constant temperature. If the composition or quality of the material changes, then its sorption behaviour also changes. Because of the complexity of sorption process the isotherms cannot be determined explicitly by calculation, but must be recorded experimentally for each product.
The relationship between water content and water activity (aw) is complex. An increase in aw is usually accompanied by an increase in water content, but in a non-linear fashion. This relationship between water activity and moisture content at a given temperature is called the moisture sorption isotherm. These curves are determined experimentally and constitute the fingerprint of a food system.
BET theory (Brunauer-Emmett-Teller) provides a calculation to describe the physical adsorption of gas molecules on a solid surface. Because of the complexity of the process, these calculations are only moderately successful; however, Stephen Brunauer was able to classify sorption isotherms into five generalized shapes as shown in Figure 2. He found that Type II and Type III isotherms require highly porous materials or desiccants, with first monolayer adsorption, followed by multilayer adsorption and finally leading to capillary condensation, explaining these materials high moisture capacity at high relative humidity.
Care must be used in extracting data from isotherms, as the representation for each axis may vary in its designation. Brunauer provided the vertical axis as moles of gas adsorbed divided by the moles of the dry material, and on the horizontal axis he used the ratio of partial pressure of the gas just over the sample, divided by its partial pressure at saturation. More modern isotherms showing the
Document 4:::
A breakthrough curve in adsorption is the course of the effluent adsorptive concentration at the outlet of a fixed bed adsorber. Breakthrough curves are important for adsorptive separation technologies and for the characterization of porous materials.
Importance
Since almost all adsorptive separation processes are dynamic -meaning, that they are running under flow - testing porous materials for those applications for their separation performance has to be tested under flow as well. Since separation processes run with mixtures of different components, measuring several breakthrough curves results in thermodynamic mixture equilibria - mixture sorption isotherms, that are hardly accessible with static manometric sorption characterization. This enables the determination of sorption selectivities in gaseous and liquid phase.
The determination of breakthrough curves is the foundation of many other processes, like the pressure swing adsorption. Within this process, the loading of one adsorber is equivalent to a breakthrough experiment.
Measurement
A fixed bed of porous materials (e.g. activated carbons and zeolites) is pressurized and purged with a carrier gas. After becoming stationary one or more adsorptives are added to the carrier gas, resulting in a step-wise change of the inlet concentration. This is in contrast to chromatographic separation processes, where pulse-wise changes of the inlet concentrations are used. The course of the adsorptive concentrations at the outlet of the fixed bed are monitored.
Results
Integration of the area above the entire breakthrough curve gives the maximum loading of the adsorptive material. Additionally, the duration of the breakthrough experiment until a certain threshold of the adsorptive concentration at the outlet can be measured, which enables the calculation of a technically usable sorption capacity. Up to this time, the quality of the product stream can be maintained. The shape of the breakthrough curves contains informat
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Which of these is an example of liquid water?
A. Frost
B. Ice
C. Rain
D. Steam
Answer:
|
|
sciq-5982
|
multiple_choice
|
What is the term for a state of matter that yields to sideways or shearing forces?
|
[
"solid",
"plasma",
"gravity",
"fluid"
] |
D
|
Relavent Documents:
Document 0:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 1:::
Surface force denoted fs is the force that acts across an internal or external surface element in a material body.
Normal forces and shear forces between objects are types of surface force. All cohesive forces and contact forces between objects are considered as surface forces.
Surface force can be decomposed into two perpendicular components: normal forces and shear forces. A normal force acts normally over an area and a shear force acts tangentially over an area.
Equations for surface force
Surface force due to pressure
, where f = force, p = pressure, and A = area on which a uniform pressure acts
Examples
Pressure related surface force
Since pressure is , and area is a ,
a pressure of over an area of will produce a surface force of .
See also
Body force
Contact force
Document 2:::
Most of the terms listed in Wikipedia glossaries are already defined and explained within Wikipedia itself. However, glossaries like this one are useful for looking up, comparing and reviewing large numbers of terms together. You can help enhance this page by adding new terms or writing definitions for existing ones.
This glossary of mechanical engineering terms pertains specifically to mechanical engineering and its sub-disciplines. For a broad overview of engineering, see glossary of engineering.
A
Abrasion – is the process of scuffing, scratching, wearing down, marring, or rubbing away. It can be intentionally imposed in a controlled process using an abrasive. Abrasion can be an undesirable effect of exposure to normal use or exposure to the elements.
Absolute zero – is the lowest possible temperature of a system, defined as zero kelvin or −273.15 °C. No experiment has yet measured a temperature of absolute zero.
Accelerated life testing – is the process of testing a product by subjecting it to conditions (stress, strain, temperatures, voltage, vibration rate, pressure etc.) in excess of its normal service parameters in an effort to uncover faults and potential modes of failure in a short amount of time. By analyzing the product's response to such tests, engineers can make predictions about the service life and maintenance intervals of a product.
Acceleration – In physics, acceleration is the rate of change of velocity of an object with respect to time. An object's acceleration is the net result of any and all forces acting on the object, as described by Newton's Second Law. The SI unit for acceleration is metre per second squared Accelerations are vector quantities (they have magnitude and direction) and add according to the parallelogram law. As a vector, the calculated net force is equal to the product of the object's mass (a scalar quantity) and its acceleration.
Accelerometer – is a device that measures proper acceleration. Proper acceleration, being
Document 3:::
Fluid kinematics is a term from fluid mechanics, usually referring to a mere mathematical description or specification of a flow field, divorced from any account of the forces and conditions that might actually create such a flow. The term fluids includes liquids or gases, but also may refer to materials that behave with fluid-like properties, including crowds of people or large numbers of grains if those are describable approximately under the continuum hypothesis as used in continuum mechanics.
Unsteady and convective effects
The composition of the material contains two types of terms: those involving the time derivative and those involving spatial derivatives. The time derivative portion is denoted as the local derivative, and represents the effects of unsteady flow. The local derivative occurs during unsteady flow, and becomes zero for steady flow.
The portion of the material derivative represented by the spatial derivatives is called the convective derivative. It accounts for the variation in fluid property, be it velocity or temperature for example, due to the motion of a fluid particle in space where its values are different.
Acceleration field
The acceleration of a particle is the time rate of change of its velocity. Using an Eulerian description for velocity, the velocity field V = V(x,y,z,t) and employing the material derivative, we obtain the acceleration field.
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In fluid mechanics, the force density is the negative gradient of pressure. It has the physical dimensions of force per unit volume. Force density is a vector field representing the flux density of the hydrostatic force within the bulk of a fluid. Force density is represented by the symbol f, and given by the following equation, where p is the pressure:
.
The net force on a differential volume element dV of the fluid is:
Force density acts in different ways which is caused by the boundary conditions. There are stick-slip boundary conditions and stick boundary conditions which affect force density.
In a sphere placed in an arbitrary non-stationary flow field of viscous incompressible fluid for stick boundary conditions where the force density's calculations leads to show the generalisation of Faxen's theorem to force multipole moments of arbitrary order.
In a sphere moving in an incompressible fluid in a non-stationary flow with mixed stick-slip boundary condition where the force of density shows an expression of the Faxén type for the total force, but the total torque and the symmetric force-dipole moment.
The force density at a point in a fluid, divided by the density, is the acceleration of the fluid at that point.
The force density f is defined as the force per unit volume, so that the net force can be calculated by:
.
The force density in an electromagnetic field is given in CGS by:
,
where is the charge density, E is the electric field, J is the current density, c is the speed of light, and B is the magnetic field.
See also
Pressure gradient
Gradient
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What is the term for a state of matter that yields to sideways or shearing forces?
A. solid
B. plasma
C. gravity
D. fluid
Answer:
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sciq-2656
|
multiple_choice
|
According to early accounts, newton was inspired to make the connection between falling bodies and astronomical motions when he saw an apple fall from a tree and realized that if the gravitational force could extend above the ground to a tree, it might also reach this?
|
[
"horizon",
"stars",
"moon",
"sun"
] |
D
|
Relavent Documents:
Document 0:::
Celestial mechanics is the branch of astronomy that deals with the motions of objects in outer space. Historically, celestial mechanics applies principles of physics (classical mechanics) to astronomical objects, such as stars and planets, to produce ephemeris data.
History
Modern analytic celestial mechanics started with Isaac Newton's Principia of 1687. The name "celestial mechanics" is more recent than that. Newton wrote that the field should be called "rational mechanics." The term "dynamics" came in a little later with Gottfried Leibniz, and over a century after Newton, Pierre-Simon Laplace introduced the term "celestial mechanics." Prior to Kepler there was little connection between exact, quantitative prediction of planetary positions, using geometrical or arithmetical techniques, and contemporary discussions of the physical causes of the planets' motion.
Johannes Kepler
Johannes Kepler (1571–1630) was the first to closely integrate the predictive geometrical astronomy, which had been dominant from Ptolemy in the 2nd century to Copernicus, with physical concepts to produce a New Astronomy, Based upon Causes, or Celestial Physics in 1609. His work led to the modern laws of planetary orbits, which he developed using his physical principles and the planetary observations made by Tycho Brahe. Kepler's model greatly improved the accuracy of predictions of planetary motion, years before Isaac Newton developed his law of gravitation in 1686.
Isaac Newton
Isaac Newton (25 December 1642–31 March 1727) is credited with introducing the idea that the motion of objects in the heavens, such as planets, the Sun, and the Moon, and the motion of objects on the ground, like cannon balls and falling apples, could be described by the same set of physical laws. In this sense he unified celestial and terrestrial dynamics. Using Newton's law of universal gravitation, proving Kepler's Laws for the case of a circular orbit is simple. Elliptical orbits involve more complex c
Document 1:::
(from Latin: "On the motion of bodies in an orbit"; abbreviated ) is the presumed title of a manuscript by Isaac Newton sent to Edmond Halley in November 1684. The manuscript was prompted by a visit from Halley earlier that year when he had questioned Newton about problems then occupying the minds of Halley and his scientific circle in London, including Sir Christopher Wren and Robert Hooke.
This manuscript gave important mathematical derivations relating to the three relations now known as "Kepler's laws of planetary motion" (before Newton's work, these had not been generally regarded as scientific laws). Halley reported the communication from Newton to the Royal Society on 10 December 1684 (Old Style). After further encouragement from Halley, Newton went on to develop and write his book (commonly known as the ) from a nucleus that can be seen in – of which nearly all of the content also reappears in the .
Contents
One of the surviving copies of De Motu was made by being entered in the Royal Society's register book, and its (Latin) text is available online.
For ease of cross-reference to the contents of De Motu that appeared again in the Principia, there are online sources for the Principia in English translation, as well as in Latin.
De motu corporum in gyrum is short enough to set out here the contents of its different sections. It contains 11 propositions, labelled as 'theorems' and 'problems', some with corollaries. Before reaching this core subject-matter, Newton begins with some preliminaries:
3 Definitions:
1: 'Centripetal force' (Newton originated this term, and its first occurrence is in this document) impels or attracts a body to some point regarded as a center. (This reappears in Definition 5 of the Principia.)
2: 'Inherent force' of a body is defined in a way that prepares for the idea of inertia and of Newton's first law (in the absence of external force, a body continues in its state of motion either at rest or in uniform motion along a stra
Document 2:::
In physics, theories of gravitation postulate mechanisms of interaction governing the movements of bodies with mass. There have been numerous theories of gravitation since ancient times. The first extant sources discussing such theories are found in ancient Greek philosophy. This work was furthered through the Middle Ages by Indian, Islamic, and European scientists, before gaining great strides during the Renaissance and Scientific Revolution—culminating in the formulation of Newton's law of gravity. This was superseded by Albert Einstein's theory of relativity in the early 20th century.
Greek philosopher Aristotle () found that objects immersed in a medium tend to fall at speeds proportional to their weight. Vitruvius () understood that objects fall based on their specific gravity. In the 6th century CE, Byzantine Alexandrian scholar John Philoponus modified the Aristotelian concept of gravity with the theory of impetus. In the 7th century, Indian astronomer Brahmagupta spoke of gravity as an attractive force. In the 14th century, European philosophers Jean Buridan and Albert of Saxony—who were influenced by certain Islamic scholars—developed the theory of impetus and linked it to the acceleration and mass of objects. Albert also developed a law of proportion regarding the relationship between the speed of an object in free fall and the time elapsed.
Italians of the 16th century found that objects in free fall tend to accelerate equally. In 1632, Galileo Galilei put forth the basic principle of relativity. The existence of the gravitational constant was explored by various researchers from the mid-17th century, helping Isaac Newton formulate his law of universal gravitation. Newton's classical mechanics were superseded in the early 20th century, when Einstein developed the special and general theories of relativity. The hypothetical force carrier of gravity remains an outlier in the search for a theory of everything, for which various models of quantum gravity ar
Document 3:::
Quaestiones quaedam philosophicae (Certain philosophical questions) is the name given to a set of notes that Isaac Newton kept for himself during his earlier years in Cambridge. They concern questions in the natural philosophy of the day that interested him. Apart from the light it throws on the formation of his own agenda for research, the major interest in these notes is the documentation of the unaided development of the scientific method in the mind of Newton, whereby every question is put to experimental test.
Introduction
The Quaestiones are contained in an octavo notebook, currently in the Cambridge University Library, which was Newton's basic notebook in which he set down in 1661 his readings in the required curriculum in Cambridge and his later readings in mechanical philosophy. He entered notes from both ends. The initial notes, in Greek, were on Aristotle's logic at one end and his ethics, at the other.
But following this, he drew a line across the page, below which appears his first notes on the new natural philosophy of his day— a compendium of limits on the radii of stars as determined by Galileo and Auzout. At the other end of the book, he interrupted his notes on Aristotle with two pages of notes on Descartes' metaphysics.
Following this, the central approximately hundred pages of this notebook is entitled Questiones quadem Philosophcae [sic], and a later motto over the title Amicus Plato amicus Aristotle magis amica veritas (Plato is my friend, Aristotle is my friend, but my best friend is truth).
Dating
The start of Quaestiones is definitely after 8 July 1661, the date on which Newton arrived at Trinity College. It is also definitely before 9 December 1664, on which day (and the following) he made notes of his observations of a comet. Other datings of the first entries are based on his handwriting—which changed drastically between the early notes of 1661 and later notes which can be dated independently to 1665. The transitional handwriting whi
Document 4:::
A set of equations describing the trajectories of objects subject to a constant gravitational force under normal Earth-bound conditions. Assuming constant acceleration g due to Earth’s gravity, Newton's law of universal gravitation simplifies to F = mg, where F is the force exerted on a mass m by the Earth’s gravitational field of strength g. Assuming constant g is reasonable for objects falling to Earth over the relatively short vertical distances of our everyday experience, but is not valid for greater distances involved in calculating more distant effects, such as spacecraft trajectories.
History
Galileo was the first to demonstrate and then formulate these equations. He used a ramp to study rolling balls, the ramp slowing the acceleration enough to measure the time taken for the ball to roll a known distance. He measured elapsed time with a water clock, using an "extremely accurate balance" to measure the amount of water.
The equations ignore air resistance, which has a dramatic effect on objects falling an appreciable distance in air, causing them to quickly approach a terminal velocity. The effect of air resistance varies enormously depending on the size and geometry of the falling object—for example, the equations are hopelessly wrong for a feather, which has a low mass but offers a large resistance to the air. (In the absence of an atmosphere all objects fall at the same rate, as astronaut David Scott demonstrated by dropping a hammer and a feather on the surface of the Moon.)
The equations also ignore the rotation of the Earth, failing to describe the Coriolis effect for example. Nevertheless, they are usually accurate enough for dense and compact objects falling over heights not exceeding the tallest man-made structures.
Overview
Near the surface of the Earth, the acceleration due to gravity = 9.807 m/s2 (metres per second squared, which might be thought of as "metres per second, per second"; or 32.18 ft/s2 as "feet per second per second") approxima
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
According to early accounts, newton was inspired to make the connection between falling bodies and astronomical motions when he saw an apple fall from a tree and realized that if the gravitational force could extend above the ground to a tree, it might also reach this?
A. horizon
B. stars
C. moon
D. sun
Answer:
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|
sciq-2715
|
multiple_choice
|
In what phase is the moon brightly illuminated?
|
[
"crescent",
"full moon",
"blue moon",
"new moon"
] |
B
|
Relavent Documents:
Document 0:::
Earthlight is the diffuse reflection of sunlight reflected from Earth's surface and clouds. Earthshine (an example of planetshine), also known as the Moon's ashen glow, is the dim illumination of the otherwise unilluminated portion of the Moon by this indirect sunlight. Earthlight on the Moon during the waxing crescent is called "the old Moon in the new Moon's arms", while that during the waning crescent is called "the new Moon in the old Moon's arms".
Visibility
Earthlight has a calculated maximum apparent magnitude of −17.7 as viewed from the Moon. When the Earth is at maximum phase, the total radiance at the lunar surface is approximately from Earthlight. This is only 0.01% of the radiance from direct Sunlight. Earthshine has a calculated maximum apparent magnitude of −3.69 as viewed from Earth.
This phenomenon is most visible from Earth at night (or astronomical twilight) a few days before or after the day of new moon, when the lunar phase is a thin crescent. On these nights, the entire lunar disk is both directly and indirectly sunlit, and is thus unevenly bright enough to see. Earthshine is most clearly seen after dusk during the waxing crescent (in the western sky) and before dawn during the waning crescent (in the eastern sky).
The term earthlight would also be suitable for an observer on the Moon seeing Earth during the lunar night, or for an astronaut inside a spacecraft looking out the window. Arthur C. Clarke uses it in this sense in his 1955 novel Earthlight.
High contrast photography is also able to reveal the night side of the moon illuminated by Earthlight during a solar eclipse.
Radio frequency transmissions are also reflected by the moon; for example, see Earth–Moon–Earth communication.
History
The phenomenon was sketched and remarked upon in the 16th century by Leonardo da Vinci, who thought that the illumination came from reflections from the Earth's oceans (we now know that clouds account for much more reflected intensity than the oceans)
Document 1:::
The Force Concept Inventory is a test measuring mastery of concepts commonly taught in a first semester of physics developed by Hestenes, Halloun, Wells, and Swackhamer (1985). It was the first such "concept inventory" and several others have been developed since for a variety of topics. The FCI was designed to assess student understanding of the Newtonian concepts of force. Hestenes (1998) found that while "nearly 80% of the [students completing introductory college physics courses] could state Newton's Third Law at the beginning of the course, FCI data showed that less than 15% of them fully understood it at the end". These results have been replicated in a number of studies involving students at a range of institutions (see sources section below), and have led to greater recognition in the physics education research community of the importance of students' "active engagement" with the materials to be mastered.
The 1995 version has 30 five-way multiple choice questions.
Example question (question 4):
Gender differences
The FCI shows a gender difference in favor of males that has been the subject of some research in regard to gender equity in education. Men score on average about 10% higher.
Document 2:::
Female education in STEM refers to child and adult female representation in the educational fields of science, technology, engineering, and mathematics (STEM). In 2017, 33% of students in STEM fields were women.
The organization UNESCO has stated that this gender disparity is due to discrimination, biases, social norms and expectations that influence the quality of education women receive and the subjects they study. UNESCO also believes that having more women in STEM fields is desirable because it would help bring about sustainable development.
Current status of girls and women in STEM education
Overall trends in STEM education
Gender differences in STEM education participation are already visible in early childhood care and education in science- and math-related play, and become more pronounced at higher levels of education. Girls appear to lose interest in STEM subjects with age, particularly between early and late adolescence. This decreased interest affects participation in advanced studies at the secondary level and in higher education. Female students represent 35% of all students enrolled in STEM-related fields of study at this level globally. Differences are also observed by disciplines, with female enrollment lowest in engineering, manufacturing and construction, natural science, mathematics and statistics and ICT fields. Significant regional and country differences in female representation in STEM studies can be observed, though, suggesting the presence of contextual factors affecting girls’ and women's engagement in these fields. Women leave STEM disciplines in disproportionate numbers during their higher education studies, in their transition to the world of work and even in their career cycle.
Learning achievement in STEM education
Data on gender differences in learning achievement present a complex picture, depending on what is measured (subject, knowledge acquisition against knowledge application), the level of education/age of students, and
Document 3:::
The actuarial credentialing and exam process usually requires passing a rigorous series of professional examinations, most often taking several years in total, before one can become recognized as a credentialed actuary. In some countries, such as Denmark, most study takes place in a university setting. In others, such as the U.S., most study takes place during employment through a series of examinations. In the UK, and countries based on its process, there is a hybrid university-exam structure.
Australia
The education system in Australia is divided into three components: an exam-based curriculum; a professionalism course; and work experience. The system is governed by the Institute of Actuaries of Australia.
The exam-based curriculum is in three parts. Part I relies on exemptions from an accredited under-graduate degree from either Bond University, Monash University, Macquarie University, University of New South Wales, University of Melbourne, Australian National University or Curtin University. The courses cover subjects including finance, financial mathematics, economics, contingencies, demography, models, probability and statistics. Students may also gain exemptions by passing the exams of the Institute of Actuaries in London. Part II is the Actuarial control cycle and is also offered by each of the universities above. Part III consists of four half-year courses of which two are compulsory and the other two allow specialization.
To become an Associate, one needs to complete Part I and Part II of the accreditation process, perform 3 years of recognized work experience, and complete a professionalism course. To become a Fellow, candidates must complete Part I, II, III, and take a professionalism course. Work experience is not required, however, as the Institute deems that those who have successfully completed Part III have shown enough level of professionalism.
China
Actuarial exams were suspended in 2014 but reintroduced in 2023.
Denmark
In Denmark it normal
Document 4:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
In what phase is the moon brightly illuminated?
A. crescent
B. full moon
C. blue moon
D. new moon
Answer:
|
|
sciq-11200
|
multiple_choice
|
Around 97% of all water on earth is what type of water?
|
[
"salt water",
"fresh water",
"excess water",
"rivers water"
] |
A
|
Relavent Documents:
Document 0:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 1:::
The Bachelor of Science in Aquatic Resources and Technology (B.Sc. in AQT) (or Bachelor of Aquatic Resource) is an undergraduate degree that prepares students to pursue careers in the public, private, or non-profit sector in areas such as marine science, fisheries science, aquaculture, aquatic resource technology, food science, management, biotechnology and hydrography. Post-baccalaureate training is available in aquatic resource management and related areas.
The Department of Animal Science and Export Agriculture, at the Uva Wellassa University of Badulla, Sri Lanka, has the largest enrollment of undergraduate majors in Aquatic Resources and Technology, with about 200 students as of 2014.
The Council on Education for Aquatic Resources and Technology includes undergraduate AQT degrees in the accreditation review of Aquatic Resources and Technology programs and schools.
See also
Marine Science
Ministry of Fisheries and Aquatic Resources Development
Document 2:::
Purified water is water that has been mechanically filtered or processed to remove impurities and make it suitable for use. Distilled water was, formerly, the most common form of purified water, but, in recent years, water is more frequently purified by other processes including capacitive deionization, reverse osmosis, carbon filtering, microfiltration, ultrafiltration, ultraviolet oxidation, or electrodeionization. Combinations of a number of these processes have come into use to produce ultrapure water of such high purity that its trace contaminants are measured in parts per billion (ppb) or parts per trillion (ppt).
Purified water has many uses, largely in the production of medications, in science and engineering laboratories and industries, and is produced in a range of purities. It is also used in the commercial beverage industry as the primary ingredient of any given trademarked bottling formula, in order to maintain product consistency. It can be produced on-site for immediate use or purchased in containers. Purified water in colloquial English can also refer to water that has been treated ("rendered potable") to neutralize, but not necessarily remove contaminants considered harmful to humans or animals.
Parameters of water purity
Purified water is usually produced by the purification of drinking water or ground water. The impurities that may need to be removed are:
inorganic ions (typically monitored as electrical conductivity or resistivity or specific tests)
organic compounds (typically monitored as TOC or by specific tests)
bacteria (monitored by total viable counts or epifluorescence)
endotoxins and nucleases (monitored by LAL or specific enzyme tests)
particulates (typically controlled by filtration)
gases (typically managed by degassing when required)
Purification methods
Distillation
Distilled water is produced by a process of distillation. Distillation involves boiling the water and then condensing the vapor into a clean container, leaving sol
Document 3:::
Fair river sharing is a kind of a fair division problem in which the waters of a river has to be divided among countries located along the river. It differs from other fair division problems in that the resource to be divided—the water—flows in one direction—from upstream countries to downstream countries. To attain any desired division, it may be required to limit the consumption of upstream countries, but this may require to give these countries some monetary compensation.
In addition to sharing river water, which is an economic good, it is often required to share river pollution (or the cost of cleaning it), which is an economic bad.
River sharing in practice
There are 148 rivers in the world flowing through two countries, 30 through three, nine through four and 13 through five or more. Some notable examples are:
The Jordan river, whose sources run from upstream Lebanon and Syria to downstream Israel and Jordan. The attempts of Syria to divert the Jordan river, starting in 1965, are cited as one of the reasons for the Six-Day War. Later, in 1994, the Israel–Jordan peace treaty determined a sharing of the waters between Israel and Jordan, by which Jordan receives water per year.
The Nile, running from upstream Ethiopia through Sudan to downstream Egypt. There is a long history of disputes over the Nile agreements of 1929 and 1959.
The Ganges, running from upstream India to downstream Bangladesh. There was controversy over the operation of the Farakka Barrage.
Between Mexico and the United States, there was controversy over the desalination facility in the Morelos Dam.
The Mekong runs from China's Yunnan Province to Myanmar, Laos, Thailand, Cambodia, and Vietnam. In 1995, Laos, Thailand, Cambodia, and Vietnam established the Mekong River Commission to assist in the management and coordinated use of the Mekong's resources. In 1996 China and Myanmar became "dialogue partners" of the MRC and the six countries now work together within a cooperative framework.
Document 4:::
Ultrapure water (UPW), high-purity water or highly purified water (HPW) is water that has been purified to uncommonly stringent specifications. Ultrapure water is a term commonly used in manufacturing to emphasize the fact that the water is treated to the highest levels of purity for all contaminant types, including: organic and inorganic compounds; dissolved and particulate matter; volatile and non-volatile; reactive, and inert; hydrophilic and hydrophobic; and dissolved gases.
UPW and the commonly used term deionized (DI) water are not the same. In addition to the fact that UPW has organic particles and dissolved gases removed, a typical UPW system has three stages: a pretreatment stage to produce purified water, a primary stage to further purify the water, and a polishing stage, the most expensive part of the treatment process.
A number of organizations and groups develop and publish standards associated with the production of UPW. For microelectronics and power, they include Semiconductor Equipment and Materials International (SEMI) (microelectronics and photovoltaic), American Society for Testing and Materials International (ASTM International) (semiconductor, power), Electric Power Research Institute (EPRI) (power), American Society of Mechanical Engineers (ASME) (power), and International Association for the Properties of Water and Steam (IAPWS) (power). Pharmaceutical plants follow water quality standards as developed by pharmacopeias, of which three examples are the United States Pharmacopeia, European Pharmacopeia, and Japanese Pharmacopeia.
The most widely used requirements for UPW quality are documented by ASTM D5127 "Standard Guide for Ultra-Pure Water Used in the Electronics and Semiconductor Industries" and SEMI F63 "Guide for ultrapure water used in semiconductor processing".
Ultra pure water is also used as boiler feedwater in the UK AGR fleet.
Sources and control
Bacteria, particles, organic, and inorganic sources of contamination vary depend
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Around 97% of all water on earth is what type of water?
A. salt water
B. fresh water
C. excess water
D. rivers water
Answer:
|
|
sciq-2948
|
multiple_choice
|
The thermal properties of what substance largely contribute to the temperature climate of europe?
|
[
"water",
"lava",
"clouds",
"soil"
] |
A
|
Relavent Documents:
Document 0:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 1:::
Computer science and engineering (CSE) is an academic program at many universities which comprises computer science classes (e.g. data structures and algorithms) and computer engineering classes (e.g computer architecture). There is no clear division in computing between science and engineering, just like in the field of materials science and engineering. CSE is also a term often used in Europe to translate the name of engineering informatics academic programs. It is offered in both undergraduate as well postgraduate with specializations.
Academic courses
Academic programs vary between colleges, but typically include a combination of topics in computer science, computer engineering, and electrical engineering. Undergraduate courses usually include programming, algorithms and data structures, computer architecture, operating systems, computer networks, parallel computing, embedded systems, algorithms design, circuit analysis and electronics, digital logic and processor design, computer graphics, scientific computing, software engineering, database systems, digital signal processing, virtualization, computer simulations and games programming. CSE programs also include core subjects of theoretical computer science such as theory of computation, numerical methods, machine learning, programming theory and paradigms. Modern academic programs also cover emerging computing fields like image processing, data science, robotics, bio-inspired computing, computational biology, autonomic computing and artificial intelligence. Most CSE programs require introductory mathematical knowledge, hence the first year of study is dominated by mathematical courses, primarily discrete mathematics, mathematical analysis, linear algebra, probability, and statistics, as well as the basics of electrical and electronic engineering, physics, and electromagnetism.
Example universities with CSE majors and departments
APJ Abdul Kalam Technological University
American International University-B
Document 2:::
A pre-STEM program is a course of study at any two-year college that prepares a student to transfer to a four-year school to earn a bachelor's degree in a STEM field.
Overview
The concept of a pre-STEM program is being developed to address America's need for more college-trained professionals in science, technology, engineering, and mathematics (STEM). It is an innovation meant to fill a gap at community colleges that do not have 'major' degree paths that students identify with on their way to earning an Associates degree. Students must complete a considerable amount of STEM coursework before transferring from a two-year school to a four-year school and earn a baccalaureate degree in a STEM field. Schools with a pre-STEM program are able to identify those students and support them with STEM-specific academic and career advising, increasing the student's chances of going on to earn a STEM baccalaureate degree in a timely fashion.
With over 50% of America's college-bound students starting their college career at public or private two-year school, and with a very small proportion of students who start college at a two-year school matriculating to and earning STEM degrees from four-year schools, pre-STEM programs have great potential for broadening participation in baccalaureate STEM studies.
Example programs
The effectiveness of pre-STEM programs is being investigated by a consortium of schools in Missouri: Moberly Area Community College, St. Charles Community College, Metropolitan Community College, and Truman State University.
A larger group of schools met at the Belknap Springs Meetings in October 2009 to discuss the challenges and opportunities presented by STEM-focused partnerships between 2-year and 4-year schools. Each program represented a two-year school and a four-year school that were trying to increase the number of people who earn a baccalaureate degree in a STEM area through various means, some of which were pre-STEM programs. Other methods includes
Document 3:::
The STEM (Science, Technology, Engineering, and Mathematics) pipeline is a critical infrastructure for fostering the development of future scientists, engineers, and problem solvers. It's the educational and career pathway that guides individuals from early childhood through to advanced research and innovation in STEM-related fields.
Description
The "pipeline" metaphor is based on the idea that having sufficient graduates requires both having sufficient input of students at the beginning of their studies, and retaining these students through completion of their academic program. The STEM pipeline is a key component of workplace diversity and of workforce development that ensures sufficient qualified candidates are available to fill scientific and technical positions.
The STEM pipeline was promoted in the United States from the 1970s onwards, as “the push for STEM (science, technology, engineering, and mathematics) education appears to have grown from a concern for the low number of future professionals to fill STEM jobs and careers and economic and educational competitiveness.”
Today, this metaphor is commonly used to describe retention problems in STEM fields, called “leaks” in the pipeline. For example, the White House reported in 2012 that 80% of minority groups and women who enroll in a STEM field switch to a non-STEM field or drop out during their undergraduate education. These leaks often vary by field, gender, ethnic and racial identity, socioeconomic background, and other factors, drawing attention to structural inequities involved in STEM education and careers.
Current efforts
The STEM pipeline concept is a useful tool for programs aiming at increasing the total number of graduates, and is especially important in efforts to increase the number of underrepresented minorities and women in STEM fields. Using STEM methodology, educational policymakers can examine the quantity and retention of students at all stages of the K–12 educational process and beyo
Document 4:::
Female education in STEM refers to child and adult female representation in the educational fields of science, technology, engineering, and mathematics (STEM). In 2017, 33% of students in STEM fields were women.
The organization UNESCO has stated that this gender disparity is due to discrimination, biases, social norms and expectations that influence the quality of education women receive and the subjects they study. UNESCO also believes that having more women in STEM fields is desirable because it would help bring about sustainable development.
Current status of girls and women in STEM education
Overall trends in STEM education
Gender differences in STEM education participation are already visible in early childhood care and education in science- and math-related play, and become more pronounced at higher levels of education. Girls appear to lose interest in STEM subjects with age, particularly between early and late adolescence. This decreased interest affects participation in advanced studies at the secondary level and in higher education. Female students represent 35% of all students enrolled in STEM-related fields of study at this level globally. Differences are also observed by disciplines, with female enrollment lowest in engineering, manufacturing and construction, natural science, mathematics and statistics and ICT fields. Significant regional and country differences in female representation in STEM studies can be observed, though, suggesting the presence of contextual factors affecting girls’ and women's engagement in these fields. Women leave STEM disciplines in disproportionate numbers during their higher education studies, in their transition to the world of work and even in their career cycle.
Learning achievement in STEM education
Data on gender differences in learning achievement present a complex picture, depending on what is measured (subject, knowledge acquisition against knowledge application), the level of education/age of students, and
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
The thermal properties of what substance largely contribute to the temperature climate of europe?
A. water
B. lava
C. clouds
D. soil
Answer:
|
|
ai2_arc-842
|
multiple_choice
|
Birds that do not receive adequate nutrition during development sing less often and for shorter periods of time as adult birds. Which best describes the outcome of nutritional stress in these songbirds?
|
[
"They are less likely to ward off predators.",
"They are less likely to obtain good nesting sites.",
"They are less likely to find adequate food supplies.",
"They are less likely to attract mates and pass on their genes."
] |
D
|
Relavent Documents:
Document 0:::
The anti-exhaustion hypothesis is a possible explanation for the existence of large repertoires and the song switching behaviour exhibited in birds. This hypothesis states that muscle exhaustion occurring due to repeating song bouts can be avoided by switching to a different song in the bird's repertoire. The anti-exhaustion hypothesis therefore predicts that birds with larger repertoires are less susceptible to exhaustion because they can readily change the song that they are producing.
The anti-exhaustion hypothesis was first proposed by Marcel Lambrechts and André Dhondt in 1988 after they carried out a study using recordings from great tits, Parus major, during the dawn chorus. There have been several studies carried out in which results have contradicted the anti-exhaustion hypothesis. Recent studies have shown that there is no evidence that the anti-exhaustion hypothesis is the cause of large repertoires in birds. Since the proposal of the anti-exhaustion hypothesis, several hypotheses have been proposed to explain the existence of repertoires and song switching behaviour in birds, including the motivation hypothesis and the warm-up hypothesis.
Anti-exhaustion hypothesis in great tits
The great tit, Parus major, is a passerine bird belonging to the family Paridae. Passerines are commonly referred to as songbirds, with most passerines singing multiple species-specific songs making a repertoire. Birds can be ranked depending on how they perform the songs in their repertoire. On one side, there are birds that sing with eventual variety and have small repertoires, meaning that each song type in their repertoire is repeated before they switch to a different song type.
On the other side, there are birds that sing with immediate variety and have larger repertoires, meaning that they switch song types continuously. The great tit, in particular, sings with eventual variety and has a small repertoire, usually consisting of two to seven different song types. Song
Document 1:::
Significant work has gone into analyzing the effects of climate change on birds. Like other animal groups, birds are affected by anthropogenic (human-caused) climate change. The research includes tracking the changes in species' life cycles over decades in response to the changing world, evaluating the role of differing evolutionary pressures and even comparing museum specimens with modern birds to track changes in appearance and body structure. Predictions of range shifts caused by the direct and indirect impacts of climate change on bird species are amongst the most important, as they are crucial for informing animal conservation work, required to minimize extinction risk from climate change.
Climate change mitigation options can also have varying impacts on birds. However, even the environmental impact of wind power is estimated to be much less threatening to birds than the continuing effects of climate change.
Causes
Climate change has raised the temperature of the Earth by about since the Industrial Revolution. As the extent of future greenhouse gas emissions and mitigation actions determines the climate change scenario taken, warming may increase from present levels by less than with rapid and comprehensive mitigation (the Paris Agreement goal) to around ( from the preindustrial) by the end of the century with very high and continually increasing greenhouse gas emissions.
Effects
Physical changes
Birds are a group of warm-blooded vertebrates constituting the class Aves, characterized by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton.
Climate change has already altered the appearance of some birds by facilitating changes to their feathers. A comparison of museum specimens of juvenile passerines from 1800s with juveniles of the same species today had shown that these birds now complete the switch from their nesting feathers to adult feathers ea
Document 2:::
Empathy in chickens is the ability of a chicken to understand and share the feelings of another chicken. The Biotechnology and Biological Sciences Research Council's (BBSRC) Animal Welfare Initiative defines and recognizes that "...hens possess a fundamental capacity to empathise..." These empathetic responses in animals are well documented and are usually discussed along with issues related to cognition. The difference between animal cognition and animal emotion is recognized by ethicists. The specific emotional attribute of empathy in chickens has not been only investigated in terms of its existence but it has applications that have resulted in the designed reduction of stress in farm-raised poultry.
Definition
The difference between animal cognition and animal emotion is recognized by ethicists. Animal cognition covers all aspects related to the thought processes in animals. Though the topics related to cognition such as self-recognition, memory, other emotions and problem-solving have been investigated, the ability to share the emotional state of another has now been established in hens.
Chickens have the basic foundations of emotional empathy. Empathy is sometimes regarded as a form of emotional intelligence and is demonstrated when hens display signs of anxiety when they observed their chicks in distressful situations. The hens have been said to "feel their chicks' pain" and to "be affected by, and share, the emotional state of another."
Scientific evidence
A study funded by the BBSRC and published in 2011 was the first to demonstrate that chickens possess empathy and the first study to use both behavioral and physiological methods to measure these traits in birds. Chicks were exposed to a puff of air, which they find mildly distressing. During the exposure, their mother's behaviour and physiological responses were monitored non-invasively. The hens altered their behaviour by decreased preening, increased alertness, and an increased numbers of vocalisati
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The common raven (Corvus corax), also known as the northern raven, is a large, all-black passerine bird. Found across the Northern Hemisphere, it is the most widely distributed of all corvids. Their Northern range encompasses Arctic and temperate regions of Eurasia and North America, and they reach as far South as Northern Africa and Central America. The common raven is an incredibly versatile passerine to account for this distribution, and their physiology varies with this versatility. This article discusses its physiology, including its homeostasis, respiration, circulatory system, and osmoregulation.
Physiology
Habitat variation and physiological regulation
Maintaining homeostasis through internal regulatory mechanisms is directly affected by habitat variation. The common raven is considered to be a homeotherm, an endotherm, and a regulator, so it is required to adjust its internal physiological state in response to environmental changes. Food habitats influence the metabolic rate of the Common Raven. Since common ravens are omnivores, metabolic rates must fluctuate according to the type of food consumed. According to one study, species that consume only fruit possess lower metabolisms compared to species that ate both fruit and insect material. The high metabolic rate of the common raven is partially due to the diversity of its diet.
Altitude is another factor that requires the common raven to regulate. Organisms existing at elevations below 1,100 m (3,500 ft) feet have lower metabolisms than organisms living at higher altitudes. Generally, warmer temperatures are associated with lower altitudes, so less energy is required to maintain a constant internal temperature. Bergmann’s rule can also be applied to the common raven. Individuals inhabiting higher altitudes and exposed to colder temperatures are usually larger than ravens living at lower latitudes or in warmer temperatures. Also, higher altitudes are associated with lower oxygen partial pressure, so rave
Document 4:::
Passerine birds produce song through the vocal organ, the syrinx, which is composed of bilaterally symmetric halves located where the trachea separates into the two bronchi. Using endoscopic techniques, it has been observed that song is produced by air passing between a set of medial and lateral labia on each side of the syrinx. Song is produced bilaterally, in both halves, through each separate set of labia unless air is prevented from flowing through one side of the syrinx. Birds regulate the airflow through the syrinx with muscles—M. syringealis dorsalis and M. tracheobronchialis dorsalis—that control the medial and lateral labia in the syrinx, whose action may close off airflow. Song may, hence, be produced unilaterally through one side of the syrinx when the labia are closed in the opposite side.
Early experiments discover lateralization
Lateral dominance of the hypoglossal nerve conveying messages from the brain to the syrinx was first observed in the 1970s. This lateral dominance was determined in a breed of canary, the waterschlager canary, bred for its long and complex song, by lesioning the ipsilateral tracheosyringeal branch of the hypoglossal nerve, disabling either the left or right syrinx. The numbers of song elements in the birds’ repertoires were greatly attenuated when the left side was cut, but only modestly attenuated when the right side was disabled, indicating left syringeal dominance of song production in these canaries. Similar lateralized effects have been observed in other species such as the white-crowned sparrow (Zonotrichia leucophrys), the Java sparrow (Lonchura oryzivora) and the zebra finch (Taeniopygia guttata), which is right-side dominant. However, denervation in these birds does not entirely silence the affected syllables but creates qualitative changes in phonology and frequency.
Respiratory control and neurophysiology
In waterslager canaries, which produce most syllables using the left syrinx, as soon as a unilaterally produced
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Birds that do not receive adequate nutrition during development sing less often and for shorter periods of time as adult birds. Which best describes the outcome of nutritional stress in these songbirds?
A. They are less likely to ward off predators.
B. They are less likely to obtain good nesting sites.
C. They are less likely to find adequate food supplies.
D. They are less likely to attract mates and pass on their genes.
Answer:
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|
ai2_arc-516
|
multiple_choice
|
Steel cans are separated from aluminum cans in a recycling center. Which of the following is the best way the recycling center can separate the steel cans from the aluminum cans?
|
[
"sort the cans by size",
"put the cans in water",
"cool the cans to a low temperature",
"put the cans under an electromagnet"
] |
D
|
Relavent Documents:
Document 0:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 1:::
In mathematical psychology and education theory, a knowledge space is a combinatorial structure used to formulate mathematical models describing the progression of a human learner. Knowledge spaces were introduced in 1985 by Jean-Paul Doignon and Jean-Claude Falmagne, and remain in extensive use in the education theory. Modern applications include two computerized tutoring systems, ALEKS and the defunct RATH.
Formally, a knowledge space assumes that a domain of knowledge is a collection of concepts or skills, each of which must be eventually mastered. Not all concepts are interchangeable; some require other concepts as prerequisites. Conversely, competency at one skill may ease the acquisition of another through similarity. A knowledge space marks out which collections of skills are feasible: they can be learned without mastering any other skills. Under reasonable assumptions, the collection of feasible competencies forms the mathematical structure known as an antimatroid.
Researchers and educators usually explore the structure of a discipline's knowledge space as a latent class model.
Motivation
Knowledge Space Theory attempts to address shortcomings of standardized testing when used in educational psychometry. Common tests, such as the SAT and ACT, compress a student's knowledge into a very small range of ordinal ranks, in the process effacing the conceptual dependencies between questions. Consequently, the tests cannot distinguish between true understanding and guesses, nor can they identify a student's particular weaknesses, only the general proportion of skills mastered. The goal of knowledge space theory is to provide a language by which exams can communicate
What the student can do and
What the student is ready to learn.
Model structure
Knowledge Space Theory-based models presume that an educational subject can be modeled as a finite set of concepts, skills, or topics. Each feasible state of knowledge about is then a subset of ; the set of
Document 2:::
Advanced Placement (AP) Physics C: Electricity and Magnetism (also known as AP Physics C: E&M or AP E&M) is an introductory physics course administered by the College Board as part of its Advanced Placement program. It is intended to proxy a second-semester calculus-based university course in electricity and magnetism. The content of Physics C: E&M overlaps with that of AP Physics 2, but Physics 2 is algebra-based and covers other topics outside of electromagnetism, while Physics C is calculus-based and only covers electromagnetism. Physics C: E&M may be combined with its mechanics counterpart to form a year-long course that prepares for both exams.
Course content
E&M is equivalent to an introductory college course in electricity and magnetism for physics or engineering majors. The course modules are:
Electrostatics
Conductors, capacitors, and dielectrics
Electric circuits
Magnetic fields
Electromagnetism.
Methods of calculus are used wherever appropriate in formulating physical principles and in applying them to physical problems. Therefore, students should have completed or be concurrently enrolled in a calculus class.
AP test
The course culminates in an optional exam for which high-performing students may receive some credit towards their college coursework, depending on the institution.
Registration
The AP examination for AP Physics C: Electricity and Magnetism is separate from the AP examination for AP Physics C: Mechanics. Before 2006, test-takers paid only once and were given the choice of taking either one or two parts of the Physics C test.
Format
The exam is typically administered on a Monday afternoon in May. The exam is configured in two categories: a 35-question multiple choice section and a 3-question free response section. Test takers are allowed to use an approved calculator during the entire exam. The test is weighted such that each section is worth half of the final score. This and AP Physics C: Mechanics are the shortest AP exams, with
Document 3:::
An item bank Or Question Bank is a term for a repository of test items that belong to a testing program, as well as all information pertaining to those items. In most applications of testing and assessment, the items are of multiple choice format, but any format can be used. Items are pulled from the bank and assigned to test forms for publication either as a paper-and-pencil test or some form of e-assessment.
Types of information
An item bank will not only include the text of each item, but also extensive information regarding test development and psychometric characteristics of the items. Examples of such information include:
Item author
Date written
Item status (e.g., new, pilot, active, retired)
Angoff ratings
Correct answer
Item format
Classical test theory statistics
Item response theory statistics
Linkage to test blueprint
Item history (e.g., usage date(s) and reviews)
User-defined fields
In India the Popular Question Bank is Oswaal Question Bank which covers All Indian Board And Competitive Exam Such as CBSE,CISCE,Pre-university course- State board and JEE,NEET,CLAT and CUET
Item banking software
Because an item bank is essentially a simple database, it can be stored in database software or even a spreadsheet such as Microsoft Excel. However, there are several dozen commercially-available software programs specifically designed for item banking. The advantages that these provide are related to assessment. For example, items are presented on the computer screen as they would appear to a test examinee, and item response theory parameters can be translated into item response functions or information functions. Additionally, there are functionalities for publication, such as formatting a set of items to be printed as a paper-and-pencil test.
Some item banks also have test administration functionalities, such as being able to deliver e-assessment or process "bubble" answer sheets.
Document 4:::
Adaptive comparative judgement is a technique borrowed from psychophysics which is able to generate reliable results for educational assessment – as such it is an alternative to traditional exam script marking. In the approach, judges are presented with pairs of student work and are then asked to choose which is better, one or the other. By means of an iterative and adaptive algorithm, a scaled distribution of student work can then be obtained without reference to criteria.
Introduction
Traditional exam script marking began in Cambridge 1792 when, with undergraduate numbers rising, the importance of proper ranking of students was growing. So in 1792 the new Proctor of Examinations, William Farish, introduced marking, a process in which every examiner gives a numerical score to each response by every student, and the overall total mark puts the students in the final rank order. Francis Galton (1869) noted that, in an unidentified year about 1863, the Senior Wrangler scored 7,634 out of a maximum of 17,000, while the Second Wrangler scored 4,123. (The 'Wooden Spoon' scored only 237.)
Prior to 1792, a team of Cambridge examiners convened at 5pm on the last day of examining, reviewed the 19 papers each student had sat – and published their rank order at midnight. Marking solved the problems of numbers and prevented unfair personal bias, and its introduction was a step towards modern objective testing, the format it is best suited to. But the technology of testing that followed, with its major emphasis on reliability and the automatisation of marking, has been an uncomfortable partner for some areas of educational achievement: assessing writing or speaking, and other kinds of performance need something more qualitative and judgemental.
The technique of Adaptive Comparative Judgement is an alternative to marking. It returns to the pre-1792 idea of sorting papers according to their quality, but retains the guarantee of reliability and fairness. It is by far the most rel
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Steel cans are separated from aluminum cans in a recycling center. Which of the following is the best way the recycling center can separate the steel cans from the aluminum cans?
A. sort the cans by size
B. put the cans in water
C. cool the cans to a low temperature
D. put the cans under an electromagnet
Answer:
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|
sciq-8088
|
multiple_choice
|
Which acid releases nitrates into soil?
|
[
"lactic",
"sulfuric",
"citric",
"uric"
] |
D
|
Relavent Documents:
Document 0:::
Reactive nitrogen ("Nr"), also known as fixed nitrogen, refers to all forms of nitrogen present in the environment except for molecular nitrogen (). While nitrogen is an essential element for life on Earth, molecular nitrogen is comparatively unreactive, and must be converted to other chemical forms via nitrogen fixation before it can be used for growth. Common Nr species include nitrogen oxides (), ammonia (), nitrous oxide (), as well as the anion nitrate ().
Biologically, nitrogen is "fixed" mainly by the microbes (eg., Bacteria and Archaea) of the soil that fix into mainly but also other species. Legumes, a type of plant in the Fabacae family, are symbionts to some of these microbes that fix . is a building block to Amino acids and proteins amongst other things essential for life. However, just over half of all reactive nitrogen entering the biosphere is attributable to anthropogenic activity such as industrial fertilizer production. While reactive nitrogen is eventually converted back into molecular nitrogen via denitrification, an excess of reactive nitrogen can lead to problems such as eutrophication in marine ecosystems.
Reactive nitrogen compounds
In the environmental context, reactive nitrogen compounds include the following classes:
oxide gases: nitric oxide, nitrogen dioxide, nitrous oxide. Containing oxidized nitrogen, mainly the result of industrial processes and internal combustion engines.
anions: nitrate, nitrite. Nitrate is a common component of fertilizers, e.g. ammonium nitrate.
amine derivatives: ammonia and ammonium salts, urea. Containing reduced nitrogen, these compounds are components of fertilizers.
All of these compounds enter into the nitrogen cycle.
As a consequence, an excess of Nr can affect the environment relatively quickly. This also means that nitrogen-related problems need to be looked at in an integrated manner.
See also
Human impact on the nitrogen cycle
Document 1:::
Nitrous acid (molecular formula ) is a weak and monoprotic acid known only in solution, in the gas phase and in the form of nitrite () salts. Nitrous acid is used to make diazonium salts from amines. The resulting diazonium salts are reagents in azo coupling reactions to give azo dyes.
Structure
In the gas phase, the planar nitrous acid molecule can adopt both a syn and an anti form. The anti form predominates at room temperature, and IR measurements indicate it is more stable by around 2.3 kJ/mol.
Preparation
Nitrous acid is usually generated by acidification of aqueous solutions of sodium nitrite with a mineral acid. The acidification is usually conducted at ice temperatures, and the HNO2 is consumed in situ. Free nitrous acid is unstable and decomposes rapidly.
Nitrous acid can also be produced by dissolving dinitrogen trioxide in water according to the equation
N2O3 + H2O → 2 HNO2
Reactions
Nitrous acid is the main chemphore in the Liebermann reagent, used to spot-test for alkaloids.
Decomposition
Gaseous nitrous acid, which is rarely encountered, decomposes into nitrogen dioxide, nitric oxide, and water:
2 HNO2 → NO2 + NO + H2O
Nitrogen dioxide disproportionates into nitric acid and nitrous acid in aqueous solution:
2 NO2 + H2O → HNO3 + HNO2
In warm or concentrated solutions, the overall reaction amounts to production of nitric acid, water, and nitric oxide:
3 HNO2 → HNO3 + 2 NO + H2O
The nitric oxide can subsequently be re-oxidized by air to nitric acid, making the overall reaction:
2 HNO2 + O2 → 2 HNO3
Reduction
With I− and Fe2+ ions, NO is formed:
2 HNO2 + 2 KI + 2 H2SO4 → I2 + 2 NO + 2 H2O + 2 K2SO4
2 HNO2 + 2 FeSO4 + 2 H2SO4 → Fe2(SO4)3 + 2 NO + 2 H2O + K2SO4
With Sn2+ ions, N2O is formed:
Document 2:::
Urea (46-0-0) accounts for more than fifty percent of the world's nitrogenous fertilizers. It is found in granular or prill form, which allows urea to be easily stored, transported and applied in agricultural settings. It is also the cheapest form of granular nitrogen fertilizer. Since urea is not an oxidizer at standard temperature and pressure, it is safer to handle and less of a security risk than other common nitrogen fertilizers, such as ammonium nitrate. However, if urea is applied to the soil surface, a meaningful fraction of applied fertilizer nitrogen may be lost to the atmosphere as ammonia gas; this only occurs under certain conditions.
Breakdown of urea
For plants to absorb nitrogen from urea it must first be broken down:
Urease is a naturally occurring enzyme that catalyzes the hydrolysis of urea to unstable carbamic acid. Rapid decomposition of carbamic acid occurs without enzyme catalysis to form ammonia and carbon dioxide. The ammonia will likely escape to the atmosphere unless it reacts with water to form ammonium (NH4+) according to the following reaction:
This is important because ammonium is a plant available source of nitrogen while ammonia is not. Additionally, the formation of the hydroxide ion may cause soils around the applied urea particle to have a pH around 9.0 which increases ammonia volatilization. This area is also highly toxic due to elevated ammonia concentration for several hours so it is recommended that urea based fertilizers not be applied or banded with planted seed at a rate that exceeds 10–20 kg/ha, depending on the crop species. It is important that there is adequate moisture because up to thirty percent of the available nitrogen can be lost through atmospheric volatilization within seventy-two hours of application.
Management considerations
Ammonia volatilization reduces the economic efficiency of agricultural cropping systems. Either yield will be reduced or additional costs will be incurred from additional nitrog
Document 3:::
In agriculture, leaching is the loss of water-soluble plant nutrients from the soil, due to rain and irrigation. Soil structure, crop planting, type and application rates of fertilizers, and other factors are taken into account to avoid excessive nutrient loss. Leaching may also refer to the practice of applying a small amount of excess irrigation where the water has a high salt content to avoid salts from building up in the soil (salinity control). Where this is practiced, drainage must also usually be employed, to carry away the excess water.
Leaching is a natural environment concern when it contributes to groundwater contamination. As water from rain, flooding, or other sources seeps into the ground, it can dissolve chemicals and carry them into the underground water supply. Of particular concern are hazardous waste dumps and landfills, and, in agriculture, excess fertilizer, improperly stored animal manure, and biocides (e.g. pesticides, fungicides, insecticides and herbicides).
Nitrogen leaching
Nitrogen is a common element in nature and an essential plant nutrient. Approximately 78% of Earth's atmosphere is nitrogen (N2). The strong bond between the atoms of N2 makes this gas quite inert and not directly usable by plants and animals. As nitrogen naturally cycles through the air, water and soil it undergoes various chemical and biological transformations. Nitrogen promotes plant growth. Livestock then eat the crops producing manure, which is returned to the soil, adding organic and mineral forms of nitrogen. The cycle is complete when the next crop uses the amended soil. To increase food production, fertilizers, such as nitrate (NO3–) and ammonium (NH4+), which are easily absorbed by plants, are introduced to the plant root zone. However, soils do not absorb the excess NO3– ions, which then move downward freely with drainage water, and are leached into groundwater, streams and oceans. The degree of leaching is affected by:
soil type and structure. For exam
Document 4:::
Nitrophily is a botanical term that indicates a preference of certain plant species for a habitat rich in nitrate. This term was first introduced by George Fuller during the 1930s. The word is a contraction of the Greek words νἰτρον (nitron) meaning "saltpetre" and φίλος (philos) meaning "friendly".
Nitrophily is traditionally expressed as a score between 1 (not nitrophilous at all) and 10 (extremely nitrophilous) according to the Ellenberg N Index. Alternatively, the response of leaf area to nitrogen supply is a relatively simple method to produce a proxy for the nitrophily. Mostly the nitrophily is consistent with the nitrate availability, where the lowest values occur with plants that grow in peat bogs (such as Drosera- and Erica-species), while the highest values occur with plants that grow on fresh organic waste such as dung piles, waste heaps and strandlines (such as Chenopodium-, and Urtica-species).
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Which acid releases nitrates into soil?
A. lactic
B. sulfuric
C. citric
D. uric
Answer:
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|
sciq-7077
|
multiple_choice
|
Segmented worms have a digestive,nervous and what type of system?
|
[
"vascular",
"lymphatic",
"circulatory",
"pulmonary"
] |
C
|
Relavent Documents:
Document 0:::
In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a function. Tissues of different types combine to form an organ which has a specific function. The intestinal wall for example is formed by epithelial tissue and smooth muscle tissue. Two or more organs working together in the execution of a specific body function form an organ system, also called a biological system or body system.
An organ's tissues can be broadly categorized as parenchyma, the functional tissue, and stroma, the structural tissue with supportive, connective, or ancillary functions. For example, the gland's tissue that makes the hormones is the parenchyma, whereas the stroma includes the nerves that innervate the parenchyma, the blood vessels that oxygenate and nourish it and carry away its metabolic wastes, and the connective tissues that provide a suitable place for it to be situated and anchored. The main tissues that make up an organ tend to have common embryologic origins, such as arising from the same germ layer. Organs exist in most multicellular organisms. In single-celled organisms such as members of the eukaryotes, the functional analogue of an organ is known as an organelle. In plants, there are three main organs.
The number of organs in any organism depends on the definition used. By one widely adopted definition, 79 organs have been identified in the human body.
Animals
Except for placozoans, multicellular animals including humans have a variety of organ systems. These specific systems are widely studied in human anatomy. The functions of these organ systems often share significant overlap. For instance, the nervous and endocrine system both operate via a shared organ, the hypothalamus. For this reason, the two systems are combined and studied as the neuroendocrine system. The sam
Document 1:::
The gastrointestinal wall of the gastrointestinal tract is made up of four layers of specialised tissue. From the inner cavity of the gut (the lumen) outwards, these are:
Mucosa
Submucosa
Muscular layer
Serosa or adventitia
The mucosa is the innermost layer of the gastrointestinal tract. It surrounds the lumen of the tract and comes into direct contact with digested food (chyme). The mucosa itself is made up of three layers: the epithelium, where most digestive, absorptive and secretory processes occur; the lamina propria, a layer of connective tissue, and the muscularis mucosae, a thin layer of smooth muscle.
The submucosa contains nerves including the submucous plexus (also called Meissner's plexus), blood vessels and elastic fibres with collagen, that stretches with increased capacity but maintains the shape of the intestine.
The muscular layer surrounds the submucosa. It comprises layers of smooth muscle in longitudinal and circular orientation that also helps with continued bowel movements (peristalsis) and the movement of digested material out of and along the gut. In between the two layers of muscle lies the myenteric plexus (also called Auerbach's plexus).
The serosa/adventitia are the final layers. These are made up of loose connective tissue and coated in mucus so as to prevent any friction damage from the intestine rubbing against other tissue. The serosa is present if the tissue is within the peritoneum, and the adventitia if the tissue is retroperitoneal.
Structure
When viewed under the microscope, the gastrointestinal wall has a consistent general form, but with certain parts differing along its course.
Mucosa
The mucosa is the innermost layer of the gastrointestinal tract. It surrounds the cavity (lumen) of the tract and comes into direct contact with digested food (chyme). The mucosa is made up of three layers:
The epithelium is the innermost layer. It is where most digestive, absorptive and secretory processes occur.
The lamina propr
Document 2:::
A biological system is a complex network which connects several biologically relevant entities. Biological organization spans several scales and are determined based different structures depending on what the system is. Examples of biological systems at the macro scale are populations of organisms. On the organ and tissue scale in mammals and other animals, examples include the circulatory system, the respiratory system, and the nervous system. On the micro to the nanoscopic scale, examples of biological systems are cells, organelles, macromolecular complexes and regulatory pathways. A biological system is not to be confused with a living system, such as a living organism.
Organ and tissue systems
These specific systems are widely studied in human anatomy and are also present in many other animals.
Respiratory system: the organs used for breathing, the pharynx, larynx, bronchi, lungs and diaphragm.
Digestive system: digestion and processing food with salivary glands, oesophagus, stomach, liver, gallbladder, pancreas, intestines, rectum and anus.
Cardiovascular system (heart and circulatory system): pumping and channeling blood to and from the body and lungs with heart, blood and blood vessels.
Urinary system: kidneys, ureters, bladder and urethra involved in fluid balance, electrolyte balance and excretion of urine.
Integumentary system: skin, hair, fat, and nails.
Skeletal system: structural support and protection with bones, cartilage, ligaments and tendons.
Endocrine system: communication within the body using hormones made by endocrine glands such as the hypothalamus, pituitary gland, pineal body or pineal gland, thyroid, parathyroid and adrenals, i.e., adrenal glands.
Lymphatic system: structures involved in the transfer of lymph between tissues and the blood stream; includes the lymph and the nodes and vessels. The lymphatic system includes functions including immune responses and development of antibodies.
Immune system: protects the organism from
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H2.00.04.4.01001: Lymphoid tissue
H2.00.05.0.00001: Muscle tissue
H2.00.05.1.00001: Smooth muscle tissue
H2.00.05.2.00001: Striated muscle tissue
H2.00.06.0.00001: Nerve tissue
H2.00.06.1.00001: Neuron
H2.00.06.2.00001: Synapse
H2.00.06.2.00001: Neuroglia
h3.01: Bones
h3.02: Joints
h3.03: Muscles
h3.04: Alimentary system
h3.05: Respiratory system
h3.06: Urinary system
h3.07: Genital system
h3.08:
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The enteric nervous system (ENS) or intrinsic nervous system is one of the main divisions of the autonomic nervous system (ANS) and consists of a mesh-like system of neurons that governs the function of the gastrointestinal tract. It is capable of acting independently of the sympathetic and parasympathetic nervous systems, although it may be influenced by them. The ENS is nicknamed the "second brain". It is derived from neural crest cells.
The enteric nervous system is capable of operating independently of the brain and spinal cord, but does rely on innervation from the vagus nerve and prevertebral ganglia in healthy subjects. However, studies have shown that the system is operable with a severed vagus nerve. The neurons of the enteric nervous system control the motor functions of the system, in addition to the secretion of gastrointestinal enzymes. These neurons communicate through many neurotransmitters similar to the CNS, including acetylcholine, dopamine, and serotonin. The large presence of serotonin and dopamine in the gut are key areas of research for neurogastroenterologists.
Structure
The enteric nervous system in humans consists of some 500 million neurons (including the various types of Dogiel cells), 0.5% of the number of neurons in the brain, five times as many as the one hundred million neurons in the human spinal cord, and about as many as in the whole nervous system of a cat. The enteric nervous system is embedded in the lining of the gastrointestinal system, beginning in the esophagus and extending down to the anus.
The neurons of the ENS are collected into two types of ganglia: myenteric (Auerbach's) and submucosal (Meissner's) plexuses. Myenteric plexuses are located between the inner and outer layers of the muscularis externa, while submucosal plexuses are located in the submucosa.
Auerbach's plexus
Auerbach's plexus, also known as the myenteric plexus, is a collection of fibers and postganglionic autonomic cell bodies that lie betwe
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Segmented worms have a digestive,nervous and what type of system?
A. vascular
B. lymphatic
C. circulatory
D. pulmonary
Answer:
|
|
sciq-7060
|
multiple_choice
|
Alcohols can be oxidized to aldehydes or _______.
|
[
"ketones",
"sugars",
"carbohydrates",
"sugars"
] |
A
|
Relavent Documents:
Document 0:::
Classification
Oxidoreductases are classified as EC 1 in the EC number classification of enzymes. Oxidoreductases can be further classified into 21 subclasses:
EC 1.1 includes oxidoreductases that act on the CH-OH group of donors (alcohol oxidoreductases such as methanol dehydrogenase)
EC 1.2 includes oxidoreductases that act on the aldehyde or oxo group of donors
EC 1.3 includes oxidoreductases that act on the CH-CH group of donors (CH-CH oxidore
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Types
As indicated in the following Biochemistry section, there are 4 types of chemically distinct eoxins that are made serially from the 15-lipoxygenase metabolite of arachidonic
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Alcohol dehydrogenases (ADH) () are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide (NAD+) to NADH. In humans and many other animals, they serve to break down alcohols that are otherwise toxic, and they also participate in the generation of useful aldehyde, ketone, or alcohol groups during the biosynthesis of various metabolites. In yeast, plants, and many bacteria, some alcohol dehydrogenases catalyze the opposite reaction as part of fermentation to ensure a constant supply of NAD+.
Evolution
Genetic evidence from comparisons of multiple organisms showed that a glutathione-dependent formaldehyde dehydrogenase, identical to a class III alcohol dehydrogenase (ADH-3/ADH5), is presumed to be the ancestral enzyme for the entire ADH family. Early on in evolution, an effective method for eliminating both endogenous and exogenous formaldehyde was important and this capacity has conserved the ancestral ADH-3 through time. Gene duplication of ADH-3, followed by series of mutations, led to the evolution of other ADHs.
The ability to produce ethanol from sugar (which is the basis of how alcoholic beverages are made) is believed to have initially evolved in yeast. Though this feature is not adaptive from an energy point of view, by making alcohol in such high concentrations so that they would be toxic to other organisms, yeast cells could effectively eliminate their competition. Since rotting fruit can contain more than 4% of ethanol, animals eating the fruit needed a system to metabolize exogenous ethanol. This was thought to explain the conservation of ethanol active ADH in species other than yeast, though ADH-3 is now known to also have a major role in nitric oxide signaling.
In humans, sequencing of the ADH1B gene (responsible for production of an alcohol dehydrogenase polypeptide) shows several functional variants. In one, t
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The metabolome refers to the complete set of small-molecule chemicals found within a biological sample. The biological sample can be a cell, a cellular organelle, an organ, a tissue, a tissue extract, a biofluid or an entire organism. The small molecule chemicals found in a given metabolome may include both endogenous metabolites that are naturally produced by an organism (such as amino acids, organic acids, nucleic acids, fatty acids, amines, sugars, vitamins, co-factors, pigments, antibiotics, etc.) as well as exogenous chemicals (such as drugs, environmental contaminants, food additives, toxins and other xenobiotics) that are not naturally produced by an organism.
In other words, there is both an endogenous metabolome and an exogenous metabolome. The endogenous metabolome can be further subdivided to include a "primary" and a "secondary" metabolome (particularly when referring to plant or microbial metabolomes). A primary metabolite is directly involved in the normal growth, development, and reproduction. A secondary metabolite is not directly involved in those processes, but usually has important ecological function. Secondary metabolites may include pigments, antibiotics or waste products derived from partially metabolized xenobiotics. The study of the metabolome is called metabolomics.
Origins
The word metabolome appears to be a blending of the words "metabolite" and "chromosome". It was constructed to imply that metabolites are indirectly encoded by genes or act on genes and gene products. The term "metabolome" was first used in 1998 and was likely coined to match with existing biological terms referring to the complete set of genes (the genome), the complete set of proteins (the proteome) and the complete set of transcripts (the transcriptome). The first book on metabolomics was published in 2003. The first journal dedicated to metabolomics (titled simply "Metabolomics") was launched in 2005 and is currently edited by Prof. Roy Goodacre. Some of the m
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The concentration of β-hydroxybutyrate in human blood plasma, as with other ketone bodies, increases through ketosis. This elevated β-hydroxybutyrate level is naturally expected, as β-hydroxybutyrate is formed from acetoacetate. The compound can be used as an energy source by the brain and skeletal muscle when blood glucose is low. Diabetic patients can have their ketone levels tested via urine or blood to indicate diabetic ketoacidosis. In alcoholic ketoacidosis, this ketone body is produced in greatest concentration. Ketogenesis occurs if oxaloacetate in the liver cells is depleted, a circumstance created by reduced carbo
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Alcohols can be oxidized to aldehydes or _______.
A. ketones
B. sugars
C. carbohydrates
D. sugars
Answer:
|
|
sciq-7784
|
multiple_choice
|
Ciliary muscles control the shape of the lens, which bends light and focuses it on what?
|
[
"the retina",
"the cornea",
"the vitreous fluid",
"the pupil"
] |
A
|
Relavent Documents:
Document 0:::
The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina. It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil. The size of the pupil is controlled by the iris, and varies depending on many factors, the most significant being the amount of light in the environment. The term "pupil" was coined by Gerard of Cremona.
In humans, the pupil is circular, but its shape varies between species; some cats, reptiles, and foxes have vertical slit pupils, goats have horizontally oriented pupils, and some catfish have annular types. In optical terms, the anatomical pupil is the eye's aperture and the iris is the aperture stop. The image of the pupil as seen from outside the eye is the entrance pupil, which does not exactly correspond to the location and size of the physical pupil because it is magnified by the cornea. On the inner edge lies a prominent structure, the collarette, marking the junction of the embryonic pupillary membrane covering the embryonic pupil.
Function
The iris is a contractile structure, consisting mainly of smooth muscle, surrounding the pupil. Light enters the eye through the pupil, and the iris regulates the amount of light by controlling the size of the pupil. This is known as the pupillary light reflex.
The iris contains two groups of smooth muscles; a circular group called the sphincter pupillae, and a radial group called the dilator pupillae. When the sphincter pupillae contract, the iris decreases or constricts the size of the pupil. The dilator pupillae, innervated by sympathetic nerves from the superior cervical ganglion, cause the pupil to dilate when they contract. These muscles are sometimes referred to as intrinsic eye muscles.
The sensory pathway (rod or cone, bipolar, ganglion) is linked with its counterpart in the other eye by a partial
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In 2-dimensional geometry, a lens is a convex region bounded by two circular arcs joined to each other at their endpoints. In order for this shape to be convex, both arcs must bow outwards (convex-convex). This shape can be formed as the intersection of two circular disks. It can also be formed as the union of two circular segments (regions between the chord of a circle and the circle itself), joined along a common chord.
Types
If the two arcs of a lens have equal radius, it is called a symmetric lens, otherwise is an asymmetric lens.
The vesica piscis is one form of a symmetric lens, formed by arcs of two circles whose centers each lie on the opposite arc. The arcs meet at angles of 120° at their endpoints.
Area
Symmetric
The area of a symmetric lens can be expressed in terms of the radius R and arc lengths θ in radians:
Asymmetric
The area of an asymmetric lens formed from circles of radii R and r with distance d between their centers is
where
is the area of a triangle with sides d, r, and R.
The two circles overlap if . For sufficiently large , the coordinate of the lens centre lies between the coordinates of the two circle centers:
For small the coordinate of the lens centre lies outside the line that connects the circle centres:
By eliminating y from the circle equations and the abscissa of the intersecting rims is
.
The sign of x, i.e., being larger or smaller than , distinguishes the two cases shown in the images.
The ordinate of the intersection is
.
Negative values under the square root indicate that the rims of the two circles do not touch
because the circles are too far apart or one circle lies entirely within the other.
The value under the square root is a biquadratic polynomial of d. The four roots of this polynomial are associated with y=0 and with the four values of d where the two circles have only one point in common.
The angles in the blue triangle of sides d, r and R are
where y is the ordinate of the intersection. Th
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Retinal mosaic is the name given to the distribution of any particular type of neuron across any particular layer in the retina. Typically such distributions are somewhat regular; it is thought that this is so that each part of the retina is served by each type of neuron in processing visual information.
The regularity of retinal mosaics can be quantitatively studied by modelling the mosaic as a spatial point pattern. This is done by treating each cell as a single point and using spatial statistics such as the Effective Radius, Packing Factor and Regularity Index.
Using adaptive optics, it is nowadays possible to image the photoreceptor mosaic (i.e. the distribution of rods and cones) in living humans, enabling the detailed study of photoreceptor density and arrangement across the retina.
In the fovea (where photoreceptor density is highest) the spacing between adjacent receptors is about 6-8 micrometer. This corresponds to an angular resolution of approximately 0.5 arc minute, effectively the upper limit of human visual acuity.
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A pre-STEM program is a course of study at any two-year college that prepares a student to transfer to a four-year school to earn a bachelor's degree in a STEM field.
Overview
The concept of a pre-STEM program is being developed to address America's need for more college-trained professionals in science, technology, engineering, and mathematics (STEM). It is an innovation meant to fill a gap at community colleges that do not have 'major' degree paths that students identify with on their way to earning an Associates degree. Students must complete a considerable amount of STEM coursework before transferring from a two-year school to a four-year school and earn a baccalaureate degree in a STEM field. Schools with a pre-STEM program are able to identify those students and support them with STEM-specific academic and career advising, increasing the student's chances of going on to earn a STEM baccalaureate degree in a timely fashion.
With over 50% of America's college-bound students starting their college career at public or private two-year school, and with a very small proportion of students who start college at a two-year school matriculating to and earning STEM degrees from four-year schools, pre-STEM programs have great potential for broadening participation in baccalaureate STEM studies.
Example programs
The effectiveness of pre-STEM programs is being investigated by a consortium of schools in Missouri: Moberly Area Community College, St. Charles Community College, Metropolitan Community College, and Truman State University.
A larger group of schools met at the Belknap Springs Meetings in October 2009 to discuss the challenges and opportunities presented by STEM-focused partnerships between 2-year and 4-year schools. Each program represented a two-year school and a four-year school that were trying to increase the number of people who earn a baccalaureate degree in a STEM area through various means, some of which were pre-STEM programs. Other methods includes
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The stroma of the iris is a fibrovascular layer of tissue. It is the upper layer of two in the iris.
Structure
The stroma is a delicate interlacement of fibres. Some circle the circumference of the iris and the majority radiate toward the pupil. Blood vessels and nerves intersperse this mesh.
In dark eyes, the stroma often contains pigment granules. Blue eyes and the eyes of albinos, however, lack pigment.
The stroma connects to a sphincter muscle (sphincter pupillae), which contracts the pupil in a circular motion, and a set of dilator muscles (dilator pupillae) which pull the iris radially to enlarge the pupil, pulling it in folds. The back surface is covered by a commonly, heavily pigmented epithelial layer that is two cells thick (the iris pigment epithelium), but the front surface has no epithelium. This anterior surface projects as the muscles dilate.
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Ciliary muscles control the shape of the lens, which bends light and focuses it on what?
A. the retina
B. the cornea
C. the vitreous fluid
D. the pupil
Answer:
|
|
sciq-6902
|
multiple_choice
|
Stars are born in clouds, and they form and grow dense due to what force?
|
[
"coreolis effect",
"gravity",
"kinetic energy",
"Big Bang theory"
] |
B
|
Relavent Documents:
Document 0:::
Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline, James Keeler, said, Astrophysics "seeks to ascertain the nature of the heavenly bodies, rather than their positions or motions in space–what they are, rather than where they are." Among the subjects studied are the Sun (solar physics), other stars, galaxies, extrasolar planets, the interstellar medium and the cosmic microwave background. Emissions from these objects are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, astrophysicists apply concepts and methods from many disciplines of physics, including classical mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics.
In practice, modern astronomical research often involves a substantial amount of work in the realms of theoretical and observational physics. Some areas of study for astrophysicists include their attempts to determine the properties of dark matter, dark energy, black holes, and other celestial bodies; and the origin and ultimate fate of the universe. Topics also studied by theoretical astrophysicists include Solar System formation and evolution; stellar dynamics and evolution; galaxy formation and evolution; magnetohydrodynamics; large-scale structure of matter in the universe; origin of cosmic rays; general relativity, special relativity, quantum and physical cosmology, including string cosmology and astroparticle physics.
History
Astronomy is an ancient science, long separated from the study of terrestrial physics. In the Aristotelian worldview, bodies in the sky appeared to be unchanging spheres whose only motion was uniform motion in a circle, while the earthl
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Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 2:::
In the Chandrasekhar–Eddington dispute of the early 20th century, English astronomer Arthur Eddington and the Indian astronomer Subrahmanyan Chandrasekhar disagreed over the correct theory to describe the final stages of a star's lifecycle. During the dispute, Chandrasekhar was at the beginning of his career and Eddington was a renowned physicist of the time. Chandrasekhar had proposed a limit, now known as Chandrasekhar limit, indicating a maximum limit for the mass of a star. In a series of conferences and encounters Eddington advocated for an alternative theory and openly criticized and made fun of Chandrasekhar's models.
Chandrasekhar's theories ended up being successful in astronomy; he would receive the Nobel Prize in Physics in 1983, for his stellar models. Chandrasekhar's limit became a supporting theoretical evidence for the existence of black holes.
Background
Arthur Eddington became a very famous and established scientist for the 1919 Eddington experiment, in which he demonstrated Albert Einstein's general relativity by measuring the deviation of light by the sun during an eclipse in Príncipe island in Africa.
In the early 1920s, three candidates for white dwarfs were known. These stars were suggested to appear at the end of the star life cycle when the stars collapse under their own weight. The remaining material forms a star in a very dense state. One of the three white dwarfs, Sirius B, a companion to Sirius, was discovered by Walter Sydney Adams after a suggestion by Arthur Eddington to use the relativistic Doppler effect as predicted by special relativity. In 1926, Eddington pointed out a problem with the models at the time which considered such dense matter as the lowest energy state. Eddington suggested that it could not be the case as stars radiate and cool down. Ralph H. Fowler solved this issue by considering that the white dwarf is held for collapsing further due to electron degeneracy pressure.
In 1929, by suggestion James Jeans stella
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In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, into an accretion disk. Most astronomical objects, such as galaxies, stars, and planets, are formed by accretion processes.
Overview
The accretion model that Earth and the other terrestrial planets formed from meteoric material was proposed in 1944 by Otto Schmidt, followed by the protoplanet theory of William McCrea (1960) and finally the capture theory of Michael Woolfson. In 1978, Andrew Prentice resurrected the initial Laplacian ideas about planet formation and developed the modern Laplacian theory. None of these models proved completely successful, and many of the proposed theories were descriptive.
The 1944 accretion model by Otto Schmidt was further developed in a quantitative way in 1969 by Viktor Safronov. He calculated, in detail, the different stages of terrestrial planet formation. Since then, the model has been further developed using intensive numerical simulations to study planetesimal accumulation. It is now accepted that stars form by the gravitational collapse of interstellar gas. Prior to collapse, this gas is mostly in the form of molecular clouds, such as the Orion Nebula. As the cloud collapses, losing potential energy, it heats up, gaining kinetic energy, and the conservation of angular momentum ensures that the cloud forms a flattened disk—the accretion disk.
Accretion of galaxies
A few hundred thousand years after the Big Bang, the Universe cooled to the point where atoms could form. As the Universe continued to expand and cool, the atoms lost enough kinetic energy, and dark matter coalesced sufficiently, to form protogalaxies. As further accretion occurred, galaxies formed. Indirect evidence is widespread. Galaxies grow through mergers and smooth gas accretion. Accretion also occurs inside galaxies, forming stars.
Accretion of stars
Stars are thought to form inside giant clouds of cold
Document 4:::
Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as "stellar nurseries" or "star-forming regions", collapse and form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function. Most stars do not form in isolation but as part of a group of stars referred as star clusters or stellar associations.
Stellar nurseries
Interstellar clouds
Spiral galaxies like the Milky Way contain stars, stellar remnants, and a diffuse interstellar medium (ISM) of gas and dust. The interstellar medium consists of 104 to 106 particles per cm3, and is typically composed of roughly 70% hydrogen, 28% helium, and 1.5% heavier elements by mass. The trace amounts of heavier elements were and are produced within stars via stellar nucleosynthesis and ejected as the stars pass beyond the end of their main sequence lifetime. Higher density regions of the interstellar medium form clouds, or diffuse nebulae, where star formation takes place. In contrast to spiral galaxies, elliptical galaxies lose the cold component of its interstellar medium within roughly a billion years, which hinders the galaxy from forming diffuse nebulae except through mergers with other galaxies.
In the dense nebulae where stars are produced, much of the hydrogen is in the molecular (H2) form, so these nebulae are called molecular clouds. The Herschel Space Observatory has revealed that filaments, or elongated dense gas structures, are truly ubiquitous in molecular clouds and central to the star formation process. They fr
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Stars are born in clouds, and they form and grow dense due to what force?
A. coreolis effect
B. gravity
C. kinetic energy
D. Big Bang theory
Answer:
|
|
sciq-577
|
multiple_choice
|
The mass of the objects and the distance between them affect the strength of what universal force?
|
[
"weight",
"states of matter",
"gravity",
"motion"
] |
C
|
Relavent Documents:
Document 0:::
In common usage, the mass of an object is often referred to as its weight, though these are in fact different concepts and quantities. Nevertheless, one object will always weigh more than another with less mass if both are subject to the same gravity (i.e. the same gravitational field strength).
In scientific contexts, mass is the amount of "matter" in an object (though "matter" may be difficult to define), but weight is the force exerted on an object's matter by gravity. At the Earth's surface, an object whose mass is exactly one kilogram weighs approximately 9.81 newtons, the product of its mass and the gravitational field strength there. The object's weight is less on Mars, where gravity is weaker; more on Saturn, where gravity is stronger; and very small in space, far from significant sources of gravity, but it always has the same mass.
Material objects at the surface of the Earth have weight despite such sometimes being difficult to measure. An object floating freely on water, for example, does not appear to have weight since it is buoyed by the water. But its weight can be measured if it is added to water in a container which is entirely supported by and weighed on a scale. Thus, the "weightless object" floating in water actually transfers its weight to the bottom of the container (where the pressure increases). Similarly, a balloon has mass but may appear to have no weight or even negative weight, due to buoyancy in air. However the weight of the balloon and the gas inside it has merely been transferred to a large area of the Earth's surface, making the weight difficult to measure. The weight of a flying airplane is similarly distributed to the ground, but does not disappear. If the airplane is in level flight, the same weight-force is distributed to the surface of the Earth as when the plane was on the runway, but spread over a larger area.
A better scientific definition of mass is its description as being a measure of inertia, which is the tendency of an
Document 1:::
In physics, action at a distance is the concept that an object's motion can be affected by another object without being physically contact (as in mechanical contact) by the other object. That is, it is the non-local interaction of objects that are separated in space. Coulomb's law and Newton's law of universal gravitation are based on action at a distance.
Historically, action at a distance was the earliest scientific model for gravity and electricity and it continues to be useful in many practical cases. In the 19th and 20th centuries, field models arose to explain these phenomena with more precision. The discovery of electrons and of special relativity lead to new action at a distance models providing alternative to field theories.
Categories of action
In the study of mechanics, action at a distance is one of three fundamental actions on matter that cause motion. The other two are direct impact (elastic or inelastic collisions) and actions in a continuous medium as in fluid mechanics or solid mechanics.
Historically, physical explanations for particular phenomena have moved between these three categories over time as new models were developed.
Action at a distance and actions in a continuous medium may be easily distinguished when the medium dynamics are visible, like waves in water or in an elastic solid. In the case of electricity or gravity, there is no medium required. In the nineteenth century, criteria like the effect of actions on intervening matter, the observation of a time delay, the apparent storage of energy, or even the possibility of a plausible mechanical model for action transmission were all accepted as evidence against action at a distance. Aether theories were alternative proposals to replace apparent action-at-a-distance in gravity and electromagnetism, in terms of continuous action inside an (invisible) medium called "aether".
Roles
The concept of action at a distance acts in multiple roles in physics and it can co-exist with other mode
Document 2:::
In non-technical terms, M-theory presents an idea about the basic substance of the universe. As of 2023, science has produced no experimental evidence to support the conclusion that M-theory is a description of the real world. Although a complete mathematical formulation of M-theory is not known, the general approach is the leading contender for a universal "Theory of Everything" that unifies gravity with other forces such as electromagnetism. M-theory aims to unify quantum mechanics with general relativity's gravitational force in a mathematically consistent way. In comparison, other theories such as loop quantum gravity are considered by physicists and researchers/students to be less elegant, because they posit gravity to be completely different from forces such as the electromagnetic force.
Background
In the early years of the 20th century, the atom – long believed to be the smallest building-block of matter – was proven to consist of even smaller components called protons, neutrons and electrons, which are known as subatomic particles. Other subatomic particles began being discovered in the 1960s. In the 1970s, it was discovered that protons and neutrons (and other hadrons) are themselves made up of smaller particles called quarks. The Standard Model is the set of rules that describes the interactions of these particles.
In the 1980s, a new mathematical model of theoretical physics, called string theory, emerged. It showed how all the different subatomic particles known to science could be constructed by hypothetical one-dimensional "strings", infinitesimal building-blocks that have only the dimension of length, but not height or width.
However, for string theory to be mathematically consistent, the strings must be in a universe of ten dimensions. This contradicts the experience that our real universe has four dimensions: three space dimensions (height, width, and length) and one time dimension. To "save" their theory, string theorists therefore added the exp
Document 3:::
The gravity of Earth, denoted by , is the net acceleration that is imparted to objects due to the combined effect of gravitation (from mass distribution within Earth) and the centrifugal force (from the Earth's rotation).
It is a vector quantity, whose direction coincides with a plumb bob and strength or magnitude is given by the norm .
In SI units this acceleration is expressed in metres per second squared (in symbols, m/s2 or m·s−2) or equivalently in newtons per kilogram (N/kg or N·kg−1). Near Earth's surface, the acceleration due to gravity, accurate to 2 significant figures, is . This means that, ignoring the effects of air resistance, the speed of an object falling freely will increase by about per second every second. This quantity is sometimes referred to informally as little (in contrast, the gravitational constant is referred to as big ).
The precise strength of Earth's gravity varies with location. The agreed upon value for is by definition. This quantity is denoted variously as , (though this sometimes means the normal gravity at the equator, ), , or simply (which is also used for the variable local value).
The weight of an object on Earth's surface is the downwards force on that object, given by Newton's second law of motion, or (). Gravitational acceleration contributes to the total gravity acceleration, but other factors, such as the rotation of Earth, also contribute, and, therefore, affect the weight of the object. Gravity does not normally include the gravitational pull of the Moon and Sun, which are accounted for in terms of tidal effects.
Variation in magnitude
A non-rotating perfect sphere of uniform mass density, or whose density varies solely with distance from the centre (spherical symmetry), would produce a gravitational field of uniform magnitude at all points on its surface. The Earth is rotating and is also not spherically symmetric; rather, it is slightly flatter at the poles while bulging at the Equator: an oblate spheroid.
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Physics education research (PER) is a form of discipline-based education research specifically related to the study of the teaching and learning of physics, often with the aim of improving the effectiveness of student learning. PER draws from other disciplines, such as sociology, cognitive science, education and linguistics, and complements them by reflecting the disciplinary knowledge and practices of physics. Approximately eighty-five institutions in the United States conduct research in science and physics education.
Goals
One primary goal of PER is to develop pedagogical techniques and strategies that will help students learn physics more effectively and help instructors to implement these techniques. Because even basic ideas in physics can be confusing, together with the possibility of scientific misconceptions formed from teaching through analogies, lecturing often does not erase common misconceptions about physics that students acquire before they are taught physics. Research often focuses on learning more about common misconceptions that students bring to the physics classroom so that techniques can be devised to help students overcome these misconceptions.
In most introductory physics courses, mechanics is usually the first area of physics that is taught. Newton's laws of motion about interactions between forces and objects are central to the study of mechanics. Many students hold the Aristotelian misconception that a net force is required to keep a body moving; instead, motion is modeled in modern physics with Newton's first law of inertia, stating that a body will keep its state of rest or movement unless a net force acts on the body. Like students who hold this misconception, Newton arrived at his three laws of motion through empirical analysis, although he did it with an extensive study of data that included astronomical observations. Students can erase such as misconception in a nearly frictionless environment, where they find that
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
The mass of the objects and the distance between them affect the strength of what universal force?
A. weight
B. states of matter
C. gravity
D. motion
Answer:
|
|
sciq-6197
|
multiple_choice
|
Saturated and unsaturated are the two main kinds of what?
|
[
"sugars",
"polymers",
"fats",
"acids"
] |
C
|
Relavent Documents:
Document 0:::
GRE Subject Biochemistry, Cell and Molecular Biology was a standardized exam provided by ETS (Educational Testing Service) that was discontinued in December 2016. It is a paper-based exam and there are no computer-based versions of it. ETS places this exam three times per year: once in April, once in October and once in November. Some graduate programs in the United States recommend taking this exam, while others require this exam score as a part of the application to their graduate programs. ETS sends a bulletin with a sample practice test to each candidate after registration for the exam. There are 180 questions within the biochemistry subject test.
Scores are scaled and then reported as a number between 200 and 990; however, in recent versions of the test, the maximum and minimum reported scores have been 760 (corresponding to the 99 percentile) and 320 (1 percentile) respectively. The mean score for all test takers from July, 2009, to July, 2012, was 526 with a standard deviation of 95.
After learning that test content from editions of the GRE® Biochemistry, Cell and Molecular Biology (BCM) Test has been compromised in Israel, ETS made the decision not to administer this test worldwide in 2016–17.
Content specification
Since many students who apply to graduate programs in biochemistry do so during the first half of their fourth year, the scope of most questions is largely that of the first three years of a standard American undergraduate biochemistry curriculum. A sampling of test item content is given below:
Biochemistry (36%)
A Chemical and Physical Foundations
Thermodynamics and kinetics
Redox states
Water, pH, acid-base reactions and buffers
Solutions and equilibria
Solute-solvent interactions
Chemical interactions and bonding
Chemical reaction mechanisms
B Structural Biology: Structure, Assembly, Organization and Dynamics
Small molecules
Macromolecules (e.g., nucleic acids, polysaccharides, proteins and complex lipids)
Supramolecular complexes (e.g.
Document 1:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 2:::
The SAT Subject Test in Biology was the name of a one-hour multiple choice test given on biology by the College Board. A student chose whether to take the test depending upon college entrance requirements for the schools in which the student is planning to apply. Until 1994, the SAT Subject Tests were known as Achievement Tests; and from 1995 until January 2005, they were known as SAT IIs. Of all SAT subject tests, the Biology E/M test was the only SAT II that allowed the test taker a choice between the ecological or molecular tests. A set of 60 questions was taken by all test takers for Biology and a choice of 20 questions was allowed between either the E or M tests. This test was graded on a scale between 200 and 800. The average for Molecular is 630 while Ecological is 591.
On January 19 2021, the College Board discontinued all SAT Subject tests, including the SAT Subject Test in Biology E/M. This was effective immediately in the United States, and the tests were to be phased out by the following summer for international students. This was done as a response to changes in college admissions due to the impact of the COVID-19 pandemic on education.
Format
This test had 80 multiple-choice questions that were to be answered in one hour. All questions had five answer choices. Students received one point for each correct answer, lost ¼ of a point for each incorrect answer, and received 0 points for questions left blank. The student's score was based entirely on his or her performance in answering the multiple-choice questions.
The questions covered a broad range of topics in general biology. There were more specific questions related respectively on ecological concepts (such as population studies and general Ecology) on the E test and molecular concepts such as DNA structure, translation, and biochemistry on the M test.
Preparation
The College Board suggested a year-long course in biology at the college preparatory level, as well as a one-year course in algebra, a
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In mathematical psychology and education theory, a knowledge space is a combinatorial structure used to formulate mathematical models describing the progression of a human learner. Knowledge spaces were introduced in 1985 by Jean-Paul Doignon and Jean-Claude Falmagne, and remain in extensive use in the education theory. Modern applications include two computerized tutoring systems, ALEKS and the defunct RATH.
Formally, a knowledge space assumes that a domain of knowledge is a collection of concepts or skills, each of which must be eventually mastered. Not all concepts are interchangeable; some require other concepts as prerequisites. Conversely, competency at one skill may ease the acquisition of another through similarity. A knowledge space marks out which collections of skills are feasible: they can be learned without mastering any other skills. Under reasonable assumptions, the collection of feasible competencies forms the mathematical structure known as an antimatroid.
Researchers and educators usually explore the structure of a discipline's knowledge space as a latent class model.
Motivation
Knowledge Space Theory attempts to address shortcomings of standardized testing when used in educational psychometry. Common tests, such as the SAT and ACT, compress a student's knowledge into a very small range of ordinal ranks, in the process effacing the conceptual dependencies between questions. Consequently, the tests cannot distinguish between true understanding and guesses, nor can they identify a student's particular weaknesses, only the general proportion of skills mastered. The goal of knowledge space theory is to provide a language by which exams can communicate
What the student can do and
What the student is ready to learn.
Model structure
Knowledge Space Theory-based models presume that an educational subject can be modeled as a finite set of concepts, skills, or topics. Each feasible state of knowledge about is then a subset of ; the set of
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A provitamin is a substance that may be converted within the body to a vitamin. The term previtamin is a synonym.
The term "provitamin" is used when it is desirable to label a substance with little or no vitamin activity, but which can be converted to an active form by normal metabolic processes.
Example
Some provitamins are:
"Provitamin A" is a name for β-carotene, which has only about 1/6 the biological activity of retinol (vitamin A); the body uses an enzyme to convert β-carotene to retinol. In other contexts, both β-carotene and retinol are simply considered to be different forms (vitamers) of vitamin A.
"Provitamin B5" is a name for panthenol, which may be converted in the body to vitamin B5 (pantothenic acid).
Menadione is a synthetic provitamin of vitamin K.
Provitamin D2 is ergosterol, and provitamin D3 is 7-dehydrocholesterol. They are converted by UV light into vitamin D. The human body produces provitamin D3 naturally; deficiency is usually caused by a lack of sun exposure, not a lack of the provitamin.
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Saturated and unsaturated are the two main kinds of what?
A. sugars
B. polymers
C. fats
D. acids
Answer:
|
|
sciq-9742
|
multiple_choice
|
What are hydrocarbons with double bonds called?
|
[
"amines",
"alcohols",
"alkenes",
"aldehydes"
] |
C
|
Relavent Documents:
Document 0:::
A carbon–carbon bond is a covalent bond between two carbon atoms. The most common form is the single bond: a bond composed of two electrons, one from each of the two atoms. The carbon–carbon single bond is a sigma bond and is formed between one hybridized orbital from each of the carbon atoms. In ethane, the orbitals are sp3-hybridized orbitals, but single bonds formed between carbon atoms with other hybridizations do occur (e.g. sp2 to sp2). In fact, the carbon atoms in the single bond need not be of the same hybridization. Carbon atoms can also form double bonds in compounds called alkenes or triple bonds in compounds called alkynes. A double bond is formed with an sp2-hybridized orbital and a p-orbital that is not involved in the hybridization. A triple bond is formed with an sp-hybridized orbital and two p-orbitals from each atom. The use of the p-orbitals forms a pi bond.
Chains and branching
Carbon is one of the few elements that can form long chains of its own atoms, a property called catenation. This coupled with the strength of the carbon–carbon bond gives rise to an enormous number of molecular forms, many of which are important structural elements of life, so carbon compounds have their own field of study: organic chemistry.
Branching is also common in C−C skeletons. Carbon atoms in a molecule are categorized by the number of carbon neighbors they have:
A primary carbon has one carbon neighbor.
A secondary carbon has two carbon neighbors.
A tertiary carbon has three carbon neighbors.
A quaternary carbon has four carbon neighbors.
In "structurally complex organic molecules", it is the three-dimensional orientation of the carbon–carbon bonds at quaternary loci which dictates the shape of the molecule. Further, quaternary loci are found in many biologically active small molecules, such as cortisone and morphine.
Synthesis
Carbon–carbon bond-forming reactions are organic reactions in which a new carbon–carbon bond is formed. They are important in th
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In chemistry, the carbon-hydrogen bond ( bond) is a chemical bond between carbon and hydrogen atoms that can be found in many organic compounds. This bond is a covalent, single bond, meaning that carbon shares its outer valence electrons with up to four hydrogens. This completes both of their outer shells, making them stable.
Carbon–hydrogen bonds have a bond length of about 1.09 Å (1.09 × 10−10 m) and a bond energy of about 413 kJ/mol (see table below). Using Pauling's scale—C (2.55) and H (2.2)—the electronegativity difference between these two atoms is 0.35. Because of this small difference in electronegativities, the bond is generally regarded as being non-polar. In structural formulas of molecules, the hydrogen atoms are often omitted. Compound classes consisting solely of bonds and bonds are alkanes, alkenes, alkynes, and aromatic hydrocarbons. Collectively they are known as hydrocarbons.
In October 2016, astronomers reported that the very basic chemical ingredients of life—the carbon-hydrogen molecule (CH, or methylidyne radical), the carbon-hydrogen positive ion () and the carbon ion ()—are the result, in large part, of ultraviolet light from stars, rather than in other ways, such as the result of turbulent events related to supernovae and young stars, as thought earlier.
Bond length
The length of the carbon-hydrogen bond varies slightly with the hybridisation of the carbon atom. A bond between a hydrogen atom and an sp2 hybridised carbon atom is about 0.6% shorter than between hydrogen and sp3 hybridised carbon. A bond between hydrogen and sp hybridised carbon is shorter still, about 3% shorter than sp3 C-H. This trend is illustrated by the molecular geometry of ethane, ethylene and acetylene.
Reactions
The C−H bond in general is very strong, so it is relatively unreactive. In several compound classes, collectively called carbon acids, the C−H bond can be sufficiently acidic for proton removal. Unactivated C−H bonds are found in alkanes and are no
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In chemical nomenclature, the IUPAC nomenclature of organic chemistry is a method of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). It is published in the Nomenclature of Organic Chemistry (informally called the Blue Book). Ideally, every possible organic compound should have a name from which an unambiguous structural formula can be created. There is also an IUPAC nomenclature of inorganic chemistry.
To avoid long and tedious names in normal communication, the official IUPAC naming recommendations are not always followed in practice, except when it is necessary to give an unambiguous and absolute definition to a compound. IUPAC names can sometimes be simpler than older names, as with ethanol, instead of ethyl alcohol. For relatively simple molecules they can be more easily understood than non-systematic names, which must be learnt or looked over. However, the common or trivial name is often substantially shorter and clearer, and so preferred. These non-systematic names are often derived from an original source of the compound. Also, very long names may be less clear than structural formulas.
Basic principles
In chemistry, a number of prefixes, suffixes and infixes are used to describe the type and position of the functional groups in the compound.
The steps for naming an organic compound are:
Identification of the parent hydride parent hydrocarbon chain. This chain must obey the following rules, in order of precedence:
It should have the maximum number of substituents of the suffix functional group. By suffix, it is meant that the parent functional group should have a suffix, unlike halogen substituents. If more than one functional group is present, the one with highest group precedence should be used.
It should have the maximum number of multiple bonds.
It should have the maximum length.
It should have the maximum number of substituents or branches cited as prefixes
It should have the ma
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A bicyclic molecule () is a molecule that features two joined rings. Bicyclic structures occur widely, for example in many biologically important molecules like α-thujene and camphor. A bicyclic compound can be carbocyclic (all of the ring atoms are carbons), or heterocyclic (the rings' atoms consist of at least two elements), like DABCO. Moreover, the two rings can both be aliphatic (e.g. decalin and norbornane), or can be aromatic (e.g. naphthalene), or a combination of aliphatic and aromatic (e.g. tetralin).
Three modes of ring junction are possible for a bicyclic compound:
In spiro compounds, the two rings share only one single atom, the spiro atom, which is usually a quaternary carbon. An example of a spirocyclic compound is the photochromic switch spiropyran.
In fused/condensed bicyclic compounds, two rings share two adjacent atoms. In other words, the rings share one covalent bond, i.e. the bridgehead atoms are directly connected (e.g. α-thujene and decalin).
In bridged bicyclic compounds, the two rings share three or more atoms, separating the two bridgehead atoms by a bridge containing at least one atom. For example, norbornane, also known as bicyclo[2.2.1]heptane, can be viewed as a pair of cyclopentane rings each sharing three of their five carbon atoms. Camphor is a more elaborate example.
Nomenclature
Bicyclic molecules are described by IUPAC nomenclature. The root of the compound name depends on the total number of atoms in all rings together, possibly followed by a suffix denoting the functional group with the highest priority. Numbering of the carbon chain always begins at one bridgehead atom (where the rings meet) and follows the carbon chain along the longest path, to the next bridgehead atom. Then numbering is continued along the second longest path and so on. Fused and bridged bicyclic compounds get the prefix bicyclo, whereas spirocyclic compounds get the prefix spiro. In between the prefix and the suffix, a pair of brackets with numerals
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In organic chemistry, a Platonic hydrocarbon is a hydrocarbon (molecule) whose structure matches one of the five Platonic solids, with carbon atoms replacing its vertices, carbon–carbon bonds replacing its edges, and hydrogen atoms as needed.
Not all Platonic solids have molecular hydrocarbon counterparts; those that do are the tetrahedron (tetrahedrane), the cube (cubane), and the dodecahedron (dodecahedrane).
Tetrahedrane
Tetrahedrane (C4H4) is a hypothetical compound. It has not yet been synthesized without substituents, but it is predicted to be kinetically stable in spite of its angle strain. Some stable derivatives, including tetra(tert-butyl)tetrahedrane (a hydrocarbon) and tetra(trimethylsilyl)tetrahedrane, have been produced.
Cubane
Cubane (C8H8) has been synthesized. Although it has high angle strain, cubane is kinetically stable, due to a lack of readily available decomposition paths.
Octahedrane
Angle strain would make an octahedron highly unstable due to inverted tetrahedral geometry at each vertex. There would also be no hydrogen atoms because four edges meet at each corner; thus, the hypothetical octahedrane molecule would be an allotrope of elemental carbon, C6, and not a hydrocarbon. The existence of octahedrane cannot be ruled out completely, although calculations have shown that it is unlikely.
Dodecahedrane
Dodecahedrane (C20H20) was first synthesized in 1982, and has minimal angle strain; the tetrahedral angle is 109.5° and the dodecahedral angle is 108°, only a slight discrepancy.
Icosahedrane
The tetravalency (4-connectedness) of carbon excludes an icosahedron because 5 edges meet at each vertex. True pentavalent carbon is unlikely; methanium, nominally , usually exists as . The hypothetical icosahedral lacks hydrogen so it is not a hydrocarbon; it is also an ion.
Both icosahedral and octahedral structures have been observed in boron compounds such as the dodecaborate ion and some of the carbon-containing carboranes.
Other polyhedr
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What are hydrocarbons with double bonds called?
A. amines
B. alcohols
C. alkenes
D. aldehydes
Answer:
|
|
sciq-6447
|
multiple_choice
|
Scientists ask questions, and then make detailed observations to try to ask more specific questions, in order to develop what?
|
[
"suggests",
"Tests",
"theories",
"hypothesis"
] |
D
|
Relavent Documents:
Document 0:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 1:::
In mathematical psychology and education theory, a knowledge space is a combinatorial structure used to formulate mathematical models describing the progression of a human learner. Knowledge spaces were introduced in 1985 by Jean-Paul Doignon and Jean-Claude Falmagne, and remain in extensive use in the education theory. Modern applications include two computerized tutoring systems, ALEKS and the defunct RATH.
Formally, a knowledge space assumes that a domain of knowledge is a collection of concepts or skills, each of which must be eventually mastered. Not all concepts are interchangeable; some require other concepts as prerequisites. Conversely, competency at one skill may ease the acquisition of another through similarity. A knowledge space marks out which collections of skills are feasible: they can be learned without mastering any other skills. Under reasonable assumptions, the collection of feasible competencies forms the mathematical structure known as an antimatroid.
Researchers and educators usually explore the structure of a discipline's knowledge space as a latent class model.
Motivation
Knowledge Space Theory attempts to address shortcomings of standardized testing when used in educational psychometry. Common tests, such as the SAT and ACT, compress a student's knowledge into a very small range of ordinal ranks, in the process effacing the conceptual dependencies between questions. Consequently, the tests cannot distinguish between true understanding and guesses, nor can they identify a student's particular weaknesses, only the general proportion of skills mastered. The goal of knowledge space theory is to provide a language by which exams can communicate
What the student can do and
What the student is ready to learn.
Model structure
Knowledge Space Theory-based models presume that an educational subject can be modeled as a finite set of concepts, skills, or topics. Each feasible state of knowledge about is then a subset of ; the set of
Document 2:::
A pre-STEM program is a course of study at any two-year college that prepares a student to transfer to a four-year school to earn a bachelor's degree in a STEM field.
Overview
The concept of a pre-STEM program is being developed to address America's need for more college-trained professionals in science, technology, engineering, and mathematics (STEM). It is an innovation meant to fill a gap at community colleges that do not have 'major' degree paths that students identify with on their way to earning an Associates degree. Students must complete a considerable amount of STEM coursework before transferring from a two-year school to a four-year school and earn a baccalaureate degree in a STEM field. Schools with a pre-STEM program are able to identify those students and support them with STEM-specific academic and career advising, increasing the student's chances of going on to earn a STEM baccalaureate degree in a timely fashion.
With over 50% of America's college-bound students starting their college career at public or private two-year school, and with a very small proportion of students who start college at a two-year school matriculating to and earning STEM degrees from four-year schools, pre-STEM programs have great potential for broadening participation in baccalaureate STEM studies.
Example programs
The effectiveness of pre-STEM programs is being investigated by a consortium of schools in Missouri: Moberly Area Community College, St. Charles Community College, Metropolitan Community College, and Truman State University.
A larger group of schools met at the Belknap Springs Meetings in October 2009 to discuss the challenges and opportunities presented by STEM-focused partnerships between 2-year and 4-year schools. Each program represented a two-year school and a four-year school that were trying to increase the number of people who earn a baccalaureate degree in a STEM area through various means, some of which were pre-STEM programs. Other methods includes
Document 3:::
The Force Concept Inventory is a test measuring mastery of concepts commonly taught in a first semester of physics developed by Hestenes, Halloun, Wells, and Swackhamer (1985). It was the first such "concept inventory" and several others have been developed since for a variety of topics. The FCI was designed to assess student understanding of the Newtonian concepts of force. Hestenes (1998) found that while "nearly 80% of the [students completing introductory college physics courses] could state Newton's Third Law at the beginning of the course, FCI data showed that less than 15% of them fully understood it at the end". These results have been replicated in a number of studies involving students at a range of institutions (see sources section below), and have led to greater recognition in the physics education research community of the importance of students' "active engagement" with the materials to be mastered.
The 1995 version has 30 five-way multiple choice questions.
Example question (question 4):
Gender differences
The FCI shows a gender difference in favor of males that has been the subject of some research in regard to gender equity in education. Men score on average about 10% higher.
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Female education in STEM refers to child and adult female representation in the educational fields of science, technology, engineering, and mathematics (STEM). In 2017, 33% of students in STEM fields were women.
The organization UNESCO has stated that this gender disparity is due to discrimination, biases, social norms and expectations that influence the quality of education women receive and the subjects they study. UNESCO also believes that having more women in STEM fields is desirable because it would help bring about sustainable development.
Current status of girls and women in STEM education
Overall trends in STEM education
Gender differences in STEM education participation are already visible in early childhood care and education in science- and math-related play, and become more pronounced at higher levels of education. Girls appear to lose interest in STEM subjects with age, particularly between early and late adolescence. This decreased interest affects participation in advanced studies at the secondary level and in higher education. Female students represent 35% of all students enrolled in STEM-related fields of study at this level globally. Differences are also observed by disciplines, with female enrollment lowest in engineering, manufacturing and construction, natural science, mathematics and statistics and ICT fields. Significant regional and country differences in female representation in STEM studies can be observed, though, suggesting the presence of contextual factors affecting girls’ and women's engagement in these fields. Women leave STEM disciplines in disproportionate numbers during their higher education studies, in their transition to the world of work and even in their career cycle.
Learning achievement in STEM education
Data on gender differences in learning achievement present a complex picture, depending on what is measured (subject, knowledge acquisition against knowledge application), the level of education/age of students, and
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Scientists ask questions, and then make detailed observations to try to ask more specific questions, in order to develop what?
A. suggests
B. Tests
C. theories
D. hypothesis
Answer:
|
|
sciq-9941
|
multiple_choice
|
A biofilm is a colony of what that is stuck to a surface such as a rock or a host’s tissues?
|
[
"vacuoles",
"eukaryotes",
"insects",
"prokaryotes"
] |
D
|
Relavent Documents:
Document 0:::
A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances (EPSs). The cells within the biofilm produce the EPS components, which are typically a polymeric conglomeration of extracellular polysaccharides, proteins, lipids and DNA. Because they have three-dimensional structure and represent a community lifestyle for microorganisms, they have been metaphorically described as "cities for microbes".
Biofilms may form on living (biotic) or non-living (abiotic) surfaces and can be prevalent in natural, industrial, and hospital settings. They may constitute a microbiome or be a portion of it. The microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism, which, by contrast, are single cells that may float or swim in a liquid medium. Biofilms can form on the teeth of most animals as dental plaque, where they may cause tooth decay and gum disease.
Microbes form a biofilm in response to a number of different factors, which may include cellular recognition of specific or non-specific attachment sites on a surface, nutritional cues, or in some cases, by exposure of planktonic cells to sub-inhibitory concentrations of antibiotics. A cell that switches to the biofilm mode of growth undergoes a phenotypic shift in behavior in which large suites of genes are differentially regulated.
A biofilm may also be considered a hydrogel, which is a complex polymer that contains many times its dry weight in water. Biofilms are not just bacterial slime layers but biological systems; the bacteria organize themselves into a coordinated functional community. Biofilms can attach to a surface such as a tooth or rock, and may include a single species or a diverse group of microorganisms. Subpopulations of cells within the biofilm differentiate to perfor
Document 1:::
The Center for Biofilm Engineering (CBE) is an interdisciplinary research, education, and technology transfer institution located on the central campus of Montana State University in Bozeman, Montana. The center was founded in April 1990 as the Center for Interfacial Microbial Process Engineering with a grant from the Engineering Research Centers (ERC) program of the National Science Foundation (NSF). The CBE integrates faculty from multiple university departments to lead multidisciplinary research teams—including graduate and undergraduate students—to advance fundamental biofilm knowledge, develop beneficial uses for microbial biofilms, and find solutions to industrially relevant biofilm problems. The center tackles biofilm issues including chronic wounds, bioremediation, and microbial corrosion through cross-disciplinary research and education among engineers, microbiologists and industry.
History
The center originated as the Institute for Chemical and Biological Process Analysis (IPA) in 1983. In 1990, the center became a national ERC as the Center for Interfacial Microbial Process Engineering based on a $7.2 million grant from the NSF. In 1993 the center assumed its current name—Center for Biofilm Engineering. The original grants expired in 2001 and the center became self-sufficient.
Institute for Chemical and Biological Process Analysis (1979–1990)
In 1979 W.G. (Bill) Characklis came to Montana State University from Rice University as a professor in civil (environmental) and chemical engineering. He assembled a multidisciplinary team of engineers, microbiologists and chemists to study the processes and effects of microbial growth at interfaces He established a cross-disciplinary environmental biotechnology institute to address the needs of industry in the areas of biofouling, microbial corrosion and biofilm technology. The Institute for Chemical and Biological Process Analysis (IPA) was chartered by the Montana Board of Regents in 1983 within the Montana Stat
Document 2:::
Extracellular polymeric substances (EPSs) are natural polymers of high molecular weight secreted by microorganisms into their environment. EPSs establish the functional and structural integrity of biofilms, and are considered the fundamental component that determines the physicochemical properties of a biofilm. EPS in the matrix of biofilms provides compositional support and protection of microbial communities from the harsh environments. Components of EPS can be of different classes of polysaccharides, lipids, nucleic acids, proteins, lipopolysaccharides, and minerals.
Components
EPSs are mostly composed of polysaccharides (exopolysaccharides) and proteins, but include other macromolecules such as DNA, lipids and humic substances. EPSs are the construction material of bacterial settlements and either remain attached to the cell's outer surface, or are secreted into its growth medium. These compounds are important in biofilm formation and cells' attachment to surfaces. EPSs constitute 50% to 90% of a biofilm's total organic matter.
Exopolysaccharides (also sometimes abbreviated EPSs; EPS sugars thereafter) are the sugar-based parts of EPS. Microorganisms synthesize a wide spectrum of multifunctional polysaccharides including intracellular polysaccharides, structural polysaccharides and extracellular polysaccharides or exopolysaccharides. Exopolysaccharides generally consist of monosaccharides and some non-carbohydrate substituents (such as acetate, pyruvate, succinate, and phosphate). Owing to the wide diversity in composition, exopolysaccharides have found diverse applications in various food and pharmaceutical industries. Many microbial EPS sugars provide properties that are almost identical to the gums currently in use. With innovative approaches, efforts are underway to supersede the traditionally used plant and algal gums by their microbial counterparts. Moreover, considerable progress has been made in discovering and developing new microbial EPS sugars tha
Document 3:::
Microbial intelligence (known as bacterial intelligence) is the intelligence shown by microorganisms. The concept encompasses complex adaptive behavior shown by single cells, and altruistic or cooperative behavior in populations of like or unlike cells mediated by chemical signalling that induces physiological or behavioral changes in cells and influences colony structures.
Complex cells, like protozoa or algae, show remarkable abilities to organize themselves in changing circumstances. Shell-building by amoebae reveals complex discrimination and manipulative skills that are ordinarily thought to occur only in multicellular organisms.
Even bacteria can display more behavior as a population. These behaviors occur in single species populations, or mixed species populations. Examples are colonies or swarms of myxobacteria, quorum sensing, and biofilms.
It has been suggested that a bacterial colony loosely mimics a biological neural network. The bacteria can take inputs in form of chemical signals, process them and then produce output chemicals to signal other bacteria in the colony.
Bacteria communication and self-organization in the context of network theory has been investigated by Eshel Ben-Jacob research group at Tel Aviv University which developed a fractal model of bacterial colony and identified linguistic and social patterns in colony lifecycle.
Examples of microbial intelligence
Bacterial
Bacterial biofilms can emerge through the collective behavior of thousands or millions of cells
Biofilms formed by Bacillus subtilis can use electric signals (ion transmission) to synchronize growth so that the innermost cells of the biofilm do not starve.
Under nutritional stress bacterial colonies can organize themselves in such a way so as to maximize nutrient availability.
Bacteria reorganize themselves under antibiotic stress.
Bacteria can swap genes (such as genes coding antibiotic resistance) between members of mixed species colonies.
Individual cells of
Document 4:::
Introduction
Many microorganisms can naturally grow together on surfaces to form complex aggregations in thick layers called biofilms. There has been a great effort to develop efficient methods for biofilm removal or prevention in clinical and food manufacturing processes. On the other hand, current research suggested that biofilms can be useful for constructive purposes such as a template of new materials that may find applications in the industry. One distinctive characteristic of biofilm formation is that microorganisms within biofilms are often much tougher and more resistant to environmental stress compared to individual microorganisms. Despite the biofilms being highly dynamic in nature, the cells inside the aggregate are stationary and are able to adapt to adverse environments. This phenomenon of enhanced resistance can be beneficial in industrial chemical production where microorganisms within biofilms may tolerate higher chemical concentration and act as robust biorefineries for various products. These microbes have also been used in bioremediation to remove contaminants from freshwater and wastewater. More novel uses of biofilms include generating electricity using microbial fuel cells. Challenges to scaling up this technology include cost, controlling the growth of biofilms, and membrane fouling.
Bioremediation
Biofilms can consist of a multitude of bacteria, fungi, and algae which are able to absorb, immobilize, and degrade many common pollutants found in wastewater. By harnessing a natural phenomenon, biofilm-mediated remediation is an environmentally friendly method for environmental cleanup. Currently, activated sludge is a common wastewater treatment process. However, biofilm-based wastewater treatment systems often use less space, are more consistent, and produce less sludge.
Biofilms contain a high amount of extracellular polymeric substance (EPS) which is made up of polysaccharides, proteins, DNA, and phospholipids. These are secreted by mic
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
A biofilm is a colony of what that is stuck to a surface such as a rock or a host’s tissues?
A. vacuoles
B. eukaryotes
C. insects
D. prokaryotes
Answer:
|
|
ai2_arc-477
|
multiple_choice
|
After a soccer game, Brittany sat under a fan because she was hot. Under the fan, she felt cooler than before. Which explains why Brittany felt cooler under the fan?
|
[
"Air moving under the fan is cooler than air that is still.",
"The evaporation of sweat absorbs heat from the skin.",
"Water vapor from the fan condenses on the skin.",
"The fan speeds convection currents in the air."
] |
B
|
Relavent Documents:
Document 0:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 1:::
Thermofluids is a branch of science and engineering encompassing four intersecting fields:
Heat transfer
Thermodynamics
Fluid mechanics
Combustion
The term is a combination of "thermo", referring to heat, and "fluids", which refers to liquids, gases and vapors. Temperature, pressure, equations of state, and transport laws all play an important role in thermofluid problems. Phase transition and chemical reactions may also be important in a thermofluid context. The subject is sometimes also referred to as "thermal fluids".
Heat transfer
Heat transfer is a discipline of thermal engineering that concerns the transfer of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer. Engineers also consider the transfer of mass of differing chemical species, either cold or hot, to achieve heat transfer.
Sections include :
Energy transfer by heat, work and mass
Laws of thermodynamics
Entropy
Refrigeration Techniques
Properties and nature of pure substances
Applications
Engineering : Predicting and analysing the performance of machines
Thermodynamics
Thermodynamics is the science of energy conversion involving heat and other forms of energy, most notably mechanical work. It studies and interrelates the macroscopic variables, such as temperature, volume and pressure, which describe physical, thermodynamic systems.
Fluid mechanics
Fluid Mechanics the study of the physical forces at work during fluid flow. Fluid mechanics can be divided into fluid kinematics, the study of fluid motion, and fluid kinetics, the study of the effect of forces on fluid motion. Fluid mechanics can further be divided into fluid statics, the study of fluids at rest, and fluid dynamics, the study of fluids in motion. Some of its more interesting concepts include momentum and reactive forces in fluid flow and fluid machinery theory and performance.
Sections include:
Flu
Document 2:::
A fan is a powered machine used to create a show of air. A fan consists of a circling arrangement of vanes or blades, generally made of wood, plastic, or metal, which act on the air. The rotating assembly of blades and hub is known as an impeller, rotor, or runner. Usually, it is contained within some form of housing, or case. This may direct the airflow, or increase safety by preventing objects from contacting the fan blades. Most fans are powered by electric motors, but other sources of power may be used, including hydraulic motors, handcranks, and internal combustion engines.
Mechanically, a fan can be any revolving vane, or vanes used for producing currents of air. Fans produce air flows with high volume and low pressure (although higher than ambient pressure), as opposed to compressors which produce high pressures at a comparatively low volume. A fan blade will often rotate when exposed to an air-fluid stream, and devices that take advantage of this, such as anemometers and wind turbines, often have designs similar to that of a fan.
Typical applications include climate control and personal thermal comfort (e.g., an electric table or floor fan), vehicle engine cooling systems (e.g., in front of a radiator), machinery cooling systems (e.g., inside computers and audio power amplifiers), ventilation, fume extraction, winnowing (e.g., separating chaff of cereal grains), removing dust (e.g. sucking as in a vacuum cleaner), drying (usually in combination with a heat source) and providing draft for a fire. Some fans may be indirectly used for cooling in the case of industrial heat exchangers.
While fans are effective at cooling people, they do not cool air, but rather work by evaporative cooling of sweat and increased heat convection into the surrounding air, due to the airflow from the fans. Thus, fans may become less effective at cooling the body if the surrounding air is near body temperature and contains high humidity.
For a more condensed history on use of re
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Engineering Equation Solver (EES) is a commercial software package used for solution of systems of simultaneous non-linear equations. It provides many useful specialized functions and equations for the solution of thermodynamics and heat transfer problems, making it a useful and widely used program for mechanical engineers working in these fields. EES stores thermodynamic properties, which eliminates iterative problem solving by hand through the use of code that calls properties at the specified thermodynamic properties. EES performs the iterative solving, eliminating the tedious and time-consuming task of acquiring thermodynamic properties with its built-in functions.
EES also includes parametric tables that allow the user to compare a number of variables at a time. Parametric tables can also be used to generate plots. EES can also integrate, both as a command in code and in tables. EES also provides optimization tools that minimize or maximize a chosen variable by varying a number of other variables. Lookup tables can be created to store information that can be accessed by a call in the code. EES code allows the user to input equations in any order and obtain a solution, but also can contain if-then statements, which can also be nested within each other to create if-then-else statements. Users can write functions for use in their code, and also procedures, which are functions with multiple outputs.
Adjusting the preferences allows the user choose a unit system, specify stop criteria, including the number of iterations, and also enable/disable unit checking and recommending units, among other options. Users can also specify guess values and variable limits to aid the iterative solving process and help EES quickly and successfully find a solution.
The program is developed by F-Chart Software, a commercial spin-off of Prof Sanford A Klein from Department of Mechanical Engineering
University of Wisconsin-Madison.
EES is included as attached software for a number
Document 4:::
A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural-gas processing, and sewage treatment. The classic example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air. Another example is the heat sink, which is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant.
Flow arrangement
There are three primary classifications of heat exchangers according to their flow arrangement. In parallel-flow heat exchangers, the two fluids enter the exchanger at the same end, and travel in parallel to one another to the other side. In counter-flow heat exchangers the fluids enter the exchanger from opposite ends. The counter current design is the most efficient, in that it can transfer the most heat from the heat (transfer) medium per unit mass due to the fact that the average temperature difference along any unit length is higher. See countercurrent exchange. In a cross-flow heat exchanger, the fluids travel roughly perpendicular to one another through the exchanger.
For efficiency, heat exchangers are designed to maximize the surface area of the wall between the two fluids, while minimizing resistance to fluid flow through the exchanger. The exchanger's performance can also be affected by the addition of fins or corrugations in one or both directions, which increase surface area and may channel fluid flow or induce turbulence.
The driving temperature across the heat trans
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
After a soccer game, Brittany sat under a fan because she was hot. Under the fan, she felt cooler than before. Which explains why Brittany felt cooler under the fan?
A. Air moving under the fan is cooler than air that is still.
B. The evaporation of sweat absorbs heat from the skin.
C. Water vapor from the fan condenses on the skin.
D. The fan speeds convection currents in the air.
Answer:
|
|
sciq-547
|
multiple_choice
|
What is the term for an infection caused by a fungal parasite?
|
[
"mydriasis",
"mitosis",
"acrobasis",
"mycosis"
] |
D
|
Relavent Documents:
Document 0:::
Mycobiota (plural noun, no singular) are a group of all the fungi present in a particular geographic region (e.g. "the mycobiota of Ireland") or habitat type (e.g. "the mycobiota of cocoa"). An analogous term for Mycobiota is funga.
Human mycobiota
Mycobiota exist on the surface and in the gastrointestinal system of humans. There are as many as sixty-six genera and 184 species in the gastrointestinal tract of healthy people. Most of these are in the Candida genera.
Though found to be present on the skin and in the gi tract in healthy individuals, the normal resident mycobiota can become pathogenic in those who are immunocompromized. Such multispecies infections lead to higher mortalities. In addition hospital-acquired infections by C. albicans have become a cause of major health concerns. A high mortality rate of 40-60% is associated with systemic infection. The best-studied of these are Candida species due to their ability to become pathogenic in immunocompromised and even in healthy hosts. Yeasts are also present on the skin, such as Malassezia species, where they consume oils secreted from the sebaceous glands. Pityrosporum (Malassezia) ovale, which is lipid-dependent and found only on humans. P. ovale was later divided into two species, P. ovale and P. orbiculare, but current sources consider these terms to refer to a single species of fungus, with M. furfur the preferred name.
Other uses
There is a peer reviewed mycological journal titled Mycobiota.
Document 1:::
Fungal infection, also known as mycosis, is a disease caused by fungi. Different types are traditionally divided according to the part of the body affected; superficial, subcutaneous, and systemic. Superficial fungal infections include common tinea of the skin, such as tinea of the body, groin, hands, feet and beard, and yeast infections such as pityriasis versicolor. Subcutaneous types include eumycetoma and chromoblastomycosis, which generally affect tissues in and beneath the skin. Systemic fungal infections are more serious and include cryptococcosis, histoplasmosis, pneumocystis pneumonia, aspergillosis and mucormycosis. Signs and symptoms range widely. There is usually a rash with superficial infection. Fungal infection within the skin or under the skin may present with a lump and skin changes. Pneumonia-like symptoms or meningitis may occur with a deeper or systemic infection.
Fungi are everywhere, but only some cause disease. Fungal infection occurs after spores are either breathed in, come into contact with skin or enter the body through the skin such as via a cut, wound or injection. It is more likely to occur in people with a weak immune system. This includes people with illnesses such as HIV/AIDS, and people taking medicines such as steroids or cancer treatments. Fungi that cause infections in people include yeasts, molds and fungi that are able to exist as both a mold and yeast. The yeast Candida albicans can live in people without producing symptoms, and is able to cause both superficial mild candidiasis in healthy people, such as oral thrush or vaginal yeast infection, and severe systemic candidiasis in those who cannot fight infection themselves.
Diagnosis is generally based on signs and symptoms, microscopy, culture, sometimes requiring a biopsy and the aid of medical imaging. Some superficial fungal infections of the skin can appear similar to other skin conditions such as eczema and lichen planus. Treatment is generally performed using antifunga
Document 2:::
Cystobasidium is a genus of fungi in the order Cystobasidiales. The type species is a fungal parasite forming small gelatinous basidiocarps (fruit bodies) on various ascomycetous fungi (including Lasiobolus and Thelebolus spp) on dung. Microscopically, it has auricularioid (laterally septate) basidia producing basidiospores that germinate by budding off yeast cells. Other species are known only from their yeast states. The yeasts Cystobasidium minutum and C. calyptogenae are rare but known human pathogens.
Taxonomy
The genus was originally described in 1898 by Swedish mycologist Gustaf Lagerheim as a subgenus of Jola and later (1924) raised to a full genus by German mycologist Walther Neuhoff. Its main distinguishing feature (microscopically) was the swollen, cyst-like probasidia from which the basidia emerge. Only one species, Cystobasidium lasioboli, was originally described, but two further species with probasidia were added by subsequent authors. In 1999, British mycologist Peter Roberts noted that Tremella fimetaria Schum. (1803) was an earlier name for Cystobasidium lasioboli and proposed the new combination Cystobasidium fimetarium.
Molecular research, based on cladistic analysis of DNA sequences, has shown that Cystobasidium (based on the type species) is a monophyletic (natural) genus. An additional 20 or so yeast species have been added to the genus, most of which were formerly placed in Rhodotorula.
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Scedosporiosis is the general name for any mycosis - i.e., fungal infection - caused by a fungus from the genus Scedosporium. Current population-based studies suggest Scedosporium prolificans (also known and recently more commonly referred to as Lomentospora prolificans) and Scedosporium apiospermum to be among the most common infecting agents from the genus, although infections caused by other members thereof are not unheard of. The latter is an asexual form (anamorph) of another fungus, Pseudallescheria boydii. The former is a “black yeast” (aka dematiaceous fungus), currently not characterized as well, although both of them have been described as saprophytes.
The fungi of this genus are more and more recognized as significant human pathogens. S. apiospermum is described as an emerging and even an “underrated” opportunistic pathogen. It was reported in a 2003 US study that Scedosporiosis had been associated with 25% of all non-Aspergillus fungal infections for organ transplant patients. In a similar 2005 study scedosporal infections caused a 58% mortality rate for transplant recipients affected with it. Among the patients with cystic fibrosis, it is the second most common fungal infection. Moreover, a certain difficulty has been reported with correctly identifying the pathogen as, for example, scedosporal infections are in some cases almost indistinguishable from infections with other filamentous fungi, like the already-mentioned Aspergillus – this difficulty could have potentially contributed to the “underrating” of the pathogen. All of this, along with the wide resistance possessed by the pathogens to the antifungal therapies currently in medical use, presents the increased interest for researchers to further study the scedoporal infections and develop treatments.
Background
First detectable description of a scedosporal disease arises in 1911 where S. apiospermum was identified as a cause of human mycetoma – a deep fungal subcutaneous infection. S. apiospermu
Document 4:::
Pathogenic fungi are fungi that cause disease in humans or other organisms. Although fungi are eukaryotic, many pathogenic fungi are microorganisms. Approximately 300 fungi are known to be pathogenic to humans; their study is called "medical mycology". Fungal infections kill more people than either tuberculosis or malaria—about 2 million people per year.
In 2022 the World Health Organization (WHO) published a list of fungal pathogens which should be a priority for public health action.
Markedly more fungi are known to be pathogenic to plant life than those of the animal kingdom. The study of fungi and other organisms pathogenic to plants is called plant pathology.
Pathogens of particular concern
According to the World Health Organization (WHO) in 2022 pathogens of particular concern are:
Critical priority Cryptococcus neoformans, Candida auris, Aspergillus fumigatus, Candida albicans.
High priority Nakaseomyces glabrata (Candida glabrata), Histoplasma spp., eumycetoma causative agents, Mucorales, Fusarium spp., Candida tropicalis, Candida parapsilosis.
Medium priority Scedosporium spp., Lomentospora prolificans, Coccidioides spp., Pichia kudriavzeveii (Candida krusei), Cryptococcus gattii, Talaromyces marneffei, Pneumocystis jirovecii, Paracoccidioides spp.
Candida
Candida species cause infections in individuals with deficient immune systems. Candida species tend to be the culprit of most fungal infections and can cause both systemic and superficial infection. Th1-type cell-mediated immunity (CMI) is required for clearance of a fungal infection.
Candida albicans is a kind of diploid yeast that commonly occurs among the human gut microflora. C. albicans is an opportunistic pathogen in humans. Abnormal over-growth of this fungus can occur, particularly in immunocompromised individuals. C. albicans has a parasexual cycle that appears to be stimulated by environmental stress.
C. auris, first described in 2009, is resistant to many frontline antifungal drugs, di
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What is the term for an infection caused by a fungal parasite?
A. mydriasis
B. mitosis
C. acrobasis
D. mycosis
Answer:
|
|
sciq-8155
|
multiple_choice
|
What can be calculated by multiplying an object’s mass in kilograms (kg) by its velocity in meters per second (m/s)?
|
[
"height",
"momentum",
"energy",
"ground speed"
] |
B
|
Relavent Documents:
Document 0:::
The newton-second (also newton second; symbol: N⋅s or N s) is the unit of impulse in the International System of Units (SI). It is dimensionally equivalent to the momentum unit kilogram-metre per second (kg⋅m/s). One newton-second corresponds to a one-newton force applied for one second.
It can be used to identify the resultant velocity of a mass if a force accelerates the mass for a specific time interval.
Definition
Momentum is given by the formula:
is the momentum in newton-seconds (N⋅s) or "kilogram-metres per second" (kg⋅m/s)
is the mass in kilograms (kg)
is the velocity in metres per second (m/s)
Examples
This table gives the magnitudes of some momenta for various masses and speeds.
See also
Power factor
Newton-metre – SI unit of torque
Orders of magnitude (momentum) – examples of momenta
Document 1:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 2:::
Advanced Placement (AP) Physics C: Mechanics (also known as AP Mechanics) is an introductory physics course administered by the College Board as part of its Advanced Placement program. It is intended to proxy a one-semester calculus-based university course in mechanics. The content of Physics C: Mechanics overlaps with that of AP Physics 1, but Physics 1 is algebra-based, while Physics C is calculus-based. Physics C: Mechanics may be combined with its electricity and magnetism counterpart to form a year-long course that prepares for both exams.
Course content
Intended to be equivalent to an introductory college course in mechanics for physics or engineering majors, the course modules are:
Kinematics
Newton's laws of motion
Work, energy and power
Systems of particles and linear momentum
Circular motion and rotation
Oscillations and gravitation.
Methods of calculus are used wherever appropriate in formulating physical principles and in applying them to physical problems. Therefore, students should have completed or be concurrently enrolled in a Calculus I class.
This course is often compared to AP Physics 1: Algebra Based for its similar course material involving kinematics, work, motion, forces, rotation, and oscillations. However, AP Physics 1: Algebra Based lacks concepts found in Calculus I, like derivatives or integrals.
This course may be combined with AP Physics C: Electricity and Magnetism to make a unified Physics C course that prepares for both exams.
AP test
The course culminates in an optional exam for which high-performing students may receive some credit towards their college coursework, depending on the institution.
Registration
The AP examination for AP Physics C: Mechanics is separate from the AP examination for AP Physics C: Electricity and Magnetism. Before 2006, test-takers paid only once and were given the choice of taking either one or two parts of the Physics C test.
Format
The exam is typically administered on a Monday aftern
Document 3:::
This article gives a list of conversion factors for several physical quantities. A number of different units (some only of historical interest) are shown and expressed in terms of the corresponding SI unit.
Conversions between units in the metric system are defined by their prefixes (for example, 1 kilogram = 1000 grams, 1 milligram = 0.001 grams) and are thus not listed in this article. Exceptions are made if the unit is commonly known by another name (for example, 1 micron = 10−6 metre). Within each table, the units are listed alphabetically, and the SI units (base or derived) are highlighted.
The following quantities are considered: length, area, volume, plane angle, solid angle, mass, density, time, frequency, velocity, volumetric flow rate, acceleration, force, pressure (or mechanical stress), torque (or moment of force), energy, power (or heat flow rate), action, dynamic viscosity, kinematic viscosity, electric current, electric charge, electric dipole, electromotive force (or electric potential difference), electrical resistance, capacitance, magnetic flux, magnetic flux density, inductance, temperature, information entropy, luminous intensity, luminance, luminous flux, illuminance, radiation.
Length
Area
Volume
Plane angle
Solid angle
Mass
Notes:
See Weight for detail of mass/weight distinction and conversion.
Avoirdupois is a system of mass based on a pound of 16 ounces, while Troy weight is the system of mass where 12 troy ounces equals one troy pound.
The symbol is used to denote standard gravity in order to avoid confusion with the (upright) g symbol for gram.
Density
Time
Frequency
Speed or velocity
A velocity consists of a speed combined with a direction; the speed part of the velocity takes units of speed.
Flow (volume)
Acceleration
Force
Pressure or mechanical stress
Torque or moment of force
Energy
Power or heat flow rate
Action
Dynamic viscosity
Kinematic viscosity
Electric current
Electric charge
Electric dipole
Elec
Document 4:::
There are four Advanced Placement (AP) Physics courses administered by the College Board as part of its Advanced Placement program: the algebra-based Physics 1 and Physics 2 and the calculus-based Physics C: Mechanics and Physics C: Electricity and Magnetism. All are intended to be at the college level. Each AP Physics course has an exam for which high-performing students may receive credit toward their college coursework.
AP Physics 1 and 2
AP Physics 1 and AP Physics 2 were introduced in 2015, replacing AP Physics B. The courses were designed to emphasize critical thinking and reasoning as well as learning through inquiry. They are algebra-based and do not require any calculus knowledge.
AP Physics 1
AP Physics 1 covers Newtonian mechanics, including:
Unit 1: Kinematics
Unit 2: Dynamics
Unit 3: Circular Motion and Gravitation
Unit 4: Energy
Unit 5: Momentum
Unit 6: Simple Harmonic Motion
Unit 7: Torque and Rotational Motion
Until 2020, the course also covered topics in electricity (including Coulomb's Law and resistive DC circuits), mechanical waves, and sound. These units were removed because they are included in AP Physics 2.
AP Physics 2
AP Physics 2 covers the following topics:
Unit 1: Fluids
Unit 2: Thermodynamics
Unit 3: Electric Force, Field, and Potential
Unit 4: Electric Circuits
Unit 5: Magnetism and Electromagnetic Induction
Unit 6: Geometric and Physical Optics
Unit 7: Quantum, Atomic, and Nuclear Physics
AP Physics C
From 1969 to 1972, AP Physics C was a single course with a single exam that covered all standard introductory university physics topics, including mechanics, fluids, electricity and magnetism, optics, and modern physics. In 1973, the College Board split the course into AP Physics C: Mechanics and AP Physics C: Electricity and Magnetism. The exam was also split into two separate 90-minute tests, each equivalent to a semester-length calculus-based college course. Until 2006, both exams could be taken for a single
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What can be calculated by multiplying an object’s mass in kilograms (kg) by its velocity in meters per second (m/s)?
A. height
B. momentum
C. energy
D. ground speed
Answer:
|
|
sciq-1426
|
multiple_choice
|
Where do biochemical reactions take place?
|
[
"between cells",
"outside of cells",
"in atoms",
"inside the organisms' cells"
] |
D
|
Relavent Documents:
Document 0:::
Biochemical engineering, also known as bioprocess engineering, is a field of study with roots stemming from chemical engineering and biological engineering. It mainly deals with the design, construction, and advancement of unit processes that involve biological organisms (such as fermentation) or organic molecules (often enzymes) and has various applications in areas of interest such as biofuels, food, pharmaceuticals, biotechnology, and water treatment processes. The role of a biochemical engineer is to take findings developed by biologists and chemists in a laboratory and translate that to a large-scale manufacturing process.
History
For hundreds of years, humans have made use of the chemical reactions of biological organisms in order to create goods. In the mid-1800s, Louis Pasteur was one of the first people to look into the role of these organisms when he researched fermentation. His work also contributed to the use of pasteurization, which is still used to this day. By the early 1900s, the use of microorganisms had expanded, and was used to make industrial products. Up to this point, biochemical engineering hadn't developed as a field yet. It wasn't until 1928 when Alexander Fleming discovered penicillin that the field of biochemical engineering was established. After this discovery, samples were gathered from around the world in order to continue research into the characteristics of microbes from places such as soils, gardens, forests, rivers, and streams. Today, biochemical engineers can be found working in a variety of industries, from food to pharmaceuticals. This is due to the increasing need for efficiency and production which requires knowledge of how biological systems and chemical reactions interact with each other and how they can be used to meet these needs.
Education
Biochemical engineering is not a major offered by most universities and is instead an area of interest under the chemical engineering major in most cases. The following universiti
Document 1:::
Biochemistry is the study of the chemical processes in living organisms. It deals with the structure and function of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules.
Articles related to biochemistry include:
0–9
2-amino-5-phosphonovalerate - 3' end - 5' end
Document 2:::
Biochemists are scientists who are trained in biochemistry. They study chemical processes and chemical transformations in living organisms. Biochemists study DNA, proteins and cell parts. The word "biochemist" is a portmanteau of "biological chemist."
Biochemists also research how certain chemical reactions happen in cells and tissues and observe and record the effects of products in food additives and medicines.
Biochemist researchers focus on playing and constructing research experiments, mainly for developing new products, updating existing products and analyzing said products. It is also the responsibility of a biochemist to present their research findings and create grant proposals to obtain funds for future research.
Biochemists study aspects of the immune system, the expressions of genes, isolating, analyzing, and synthesizing different products, mutations that lead to cancers, and manage laboratory teams and monitor laboratory work. Biochemists also have to have the capabilities of designing and building laboratory equipment and devise new methods of producing correct results for products.
The most common industry role is the development of biochemical products and processes. Identifying substances' chemical and physical properties in biological systems is of great importance, and can be carried out by doing various types of analysis. Biochemists must also prepare technical reports after collecting, analyzing and summarizing the information and trends found.
In biochemistry, researchers often break down complicated biological systems into their component parts. They study the effects of foods, drugs, allergens and other substances on living tissues; they research molecular biology, the study of life at the molecular level and the study of genes and gene expression; and they study chemical reactions in metabolism, growth, reproduction, and heredity, and apply techniques drawn from biotechnology and genetic engineering to help them in their research. Abou
Document 3:::
The following outline is provided as an overview of and topical guide to biophysics:
Biophysics – interdisciplinary science that uses the methods of physics to study biological systems.
Nature of biophysics
Biophysics is
An academic discipline – branch of knowledge that is taught and researched at the college or university level. Disciplines are defined (in part), and recognized by the academic journals in which research is published, and the learned societies and academic departments or faculties to which their practitioners belong.
A scientific field (a branch of science) – widely recognized category of specialized expertise within science, and typically embodies its own terminology and nomenclature. Such a field will usually be represented by one or more scientific journals, where peer-reviewed research is published.
A natural science – one that seeks to elucidate the rules that govern the natural world using empirical and scientific methods.
A biological science – concerned with the study of living organisms, including their structure, function, growth, evolution, distribution, and taxonomy.
A branch of physics – concerned with the study of matter and its motion through space and time, along with related concepts such as energy and force.
An interdisciplinary field – field of science that overlaps with other sciences
Scope of biophysics research
Biomolecular scale
Biomolecule
Biomolecular structure
Organismal scale
Animal locomotion
Biomechanics
Biomineralization
Motility
Environmental scale
Biophysical environment
Biophysics research overlaps with
Agrophysics
Biochemistry
Biophysical chemistry
Bioengineering
Biogeophysics
Nanotechnology
Systems biology
Branches of biophysics
Astrobiophysics – field of intersection between astrophysics and biophysics concerned with the influence of the astrophysical phenomena upon life on planet Earth or some other planet in general.
Medical biophysics – interdisciplinary field that applies me
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This list of life sciences comprises the branches of science that involve the scientific study of life – such as microorganisms, plants, and animals including human beings. This science is one of the two major branches of natural science, the other being physical science, which is concerned with non-living matter. Biology is the overall natural science that studies life, with the other life sciences as its sub-disciplines.
Some life sciences focus on a specific type of organism. For example, zoology is the study of animals, while botany is the study of plants. Other life sciences focus on aspects common to all or many life forms, such as anatomy and genetics. Some focus on the micro-scale (e.g. molecular biology, biochemistry) other on larger scales (e.g. cytology, immunology, ethology, pharmacy, ecology). Another major branch of life sciences involves understanding the mindneuroscience. Life sciences discoveries are helpful in improving the quality and standard of life and have applications in health, agriculture, medicine, and the pharmaceutical and food science industries. For example, it has provided information on certain diseases which has overall aided in the understanding of human health.
Basic life science branches
Biology – scientific study of life
Anatomy – study of form and function, in plants, animals, and other organisms, or specifically in humans
Astrobiology – the study of the formation and presence of life in the universe
Bacteriology – study of bacteria
Biotechnology – study of combination of both the living organism and technology
Biochemistry – study of the chemical reactions required for life to exist and function, usually a focus on the cellular level
Bioinformatics – developing of methods or software tools for storing, retrieving, organizing and analyzing biological data to generate useful biological knowledge
Biolinguistics – the study of the biology and evolution of language.
Biological anthropology – the study of humans, non-hum
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Where do biochemical reactions take place?
A. between cells
B. outside of cells
C. in atoms
D. inside the organisms' cells
Answer:
|
|
sciq-10772
|
multiple_choice
|
What does all matter consist of?
|
[
"oxygen",
"atoms",
"helium",
"carbon"
] |
B
|
Relavent Documents:
Document 0:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 1:::
In mathematical psychology and education theory, a knowledge space is a combinatorial structure used to formulate mathematical models describing the progression of a human learner. Knowledge spaces were introduced in 1985 by Jean-Paul Doignon and Jean-Claude Falmagne, and remain in extensive use in the education theory. Modern applications include two computerized tutoring systems, ALEKS and the defunct RATH.
Formally, a knowledge space assumes that a domain of knowledge is a collection of concepts or skills, each of which must be eventually mastered. Not all concepts are interchangeable; some require other concepts as prerequisites. Conversely, competency at one skill may ease the acquisition of another through similarity. A knowledge space marks out which collections of skills are feasible: they can be learned without mastering any other skills. Under reasonable assumptions, the collection of feasible competencies forms the mathematical structure known as an antimatroid.
Researchers and educators usually explore the structure of a discipline's knowledge space as a latent class model.
Motivation
Knowledge Space Theory attempts to address shortcomings of standardized testing when used in educational psychometry. Common tests, such as the SAT and ACT, compress a student's knowledge into a very small range of ordinal ranks, in the process effacing the conceptual dependencies between questions. Consequently, the tests cannot distinguish between true understanding and guesses, nor can they identify a student's particular weaknesses, only the general proportion of skills mastered. The goal of knowledge space theory is to provide a language by which exams can communicate
What the student can do and
What the student is ready to learn.
Model structure
Knowledge Space Theory-based models presume that an educational subject can be modeled as a finite set of concepts, skills, or topics. Each feasible state of knowledge about is then a subset of ; the set of
Document 2:::
Advanced Placement (AP) Physics C: Electricity and Magnetism (also known as AP Physics C: E&M or AP E&M) is an introductory physics course administered by the College Board as part of its Advanced Placement program. It is intended to proxy a second-semester calculus-based university course in electricity and magnetism. The content of Physics C: E&M overlaps with that of AP Physics 2, but Physics 2 is algebra-based and covers other topics outside of electromagnetism, while Physics C is calculus-based and only covers electromagnetism. Physics C: E&M may be combined with its mechanics counterpart to form a year-long course that prepares for both exams.
Course content
E&M is equivalent to an introductory college course in electricity and magnetism for physics or engineering majors. The course modules are:
Electrostatics
Conductors, capacitors, and dielectrics
Electric circuits
Magnetic fields
Electromagnetism.
Methods of calculus are used wherever appropriate in formulating physical principles and in applying them to physical problems. Therefore, students should have completed or be concurrently enrolled in a calculus class.
AP test
The course culminates in an optional exam for which high-performing students may receive some credit towards their college coursework, depending on the institution.
Registration
The AP examination for AP Physics C: Electricity and Magnetism is separate from the AP examination for AP Physics C: Mechanics. Before 2006, test-takers paid only once and were given the choice of taking either one or two parts of the Physics C test.
Format
The exam is typically administered on a Monday afternoon in May. The exam is configured in two categories: a 35-question multiple choice section and a 3-question free response section. Test takers are allowed to use an approved calculator during the entire exam. The test is weighted such that each section is worth half of the final score. This and AP Physics C: Mechanics are the shortest AP exams, with
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There are four Advanced Placement (AP) Physics courses administered by the College Board as part of its Advanced Placement program: the algebra-based Physics 1 and Physics 2 and the calculus-based Physics C: Mechanics and Physics C: Electricity and Magnetism. All are intended to be at the college level. Each AP Physics course has an exam for which high-performing students may receive credit toward their college coursework.
AP Physics 1 and 2
AP Physics 1 and AP Physics 2 were introduced in 2015, replacing AP Physics B. The courses were designed to emphasize critical thinking and reasoning as well as learning through inquiry. They are algebra-based and do not require any calculus knowledge.
AP Physics 1
AP Physics 1 covers Newtonian mechanics, including:
Unit 1: Kinematics
Unit 2: Dynamics
Unit 3: Circular Motion and Gravitation
Unit 4: Energy
Unit 5: Momentum
Unit 6: Simple Harmonic Motion
Unit 7: Torque and Rotational Motion
Until 2020, the course also covered topics in electricity (including Coulomb's Law and resistive DC circuits), mechanical waves, and sound. These units were removed because they are included in AP Physics 2.
AP Physics 2
AP Physics 2 covers the following topics:
Unit 1: Fluids
Unit 2: Thermodynamics
Unit 3: Electric Force, Field, and Potential
Unit 4: Electric Circuits
Unit 5: Magnetism and Electromagnetic Induction
Unit 6: Geometric and Physical Optics
Unit 7: Quantum, Atomic, and Nuclear Physics
AP Physics C
From 1969 to 1972, AP Physics C was a single course with a single exam that covered all standard introductory university physics topics, including mechanics, fluids, electricity and magnetism, optics, and modern physics. In 1973, the College Board split the course into AP Physics C: Mechanics and AP Physics C: Electricity and Magnetism. The exam was also split into two separate 90-minute tests, each equivalent to a semester-length calculus-based college course. Until 2006, both exams could be taken for a single
Document 4:::
The SAT Subject Test in Physics, Physics SAT II, or simply the Physics SAT, was a one-hour multiple choice test on physics administered by the College Board in the United States. A high school student generally chose to take the test to fulfill college entrance requirements for the schools at which the student was planning to apply. Until 1994, the SAT Subject Tests were known as Achievement Tests; until January 2005, they were known as SAT IIs; they are still well known by this name.
The material tested on the Physics SAT was supposed to be equivalent to that taught in a junior- or senior-level high school physics class. It required critical thinking and test-taking strategies, at which high school freshmen or sophomores may have been inexperienced. The Physics SAT tested more than what normal state requirements were; therefore, many students prepared for the Physics SAT using a preparatory book or by taking an AP course in physics.
On January 19 2021, the College Board discontinued all SAT Subject tests, including the SAT Subject Test in Physics. This was effective immediately in the United States, and the tests were to be phased out by the following summer for international students. This was done as a response to changes in college admissions due to the impact of the COVID-19 pandemic on education.
Format
The SAT Subject Test in Physics had 75 questions and consisted of two parts: Part A and Part B.
Part A:
First 12 or 13 questions
4 groups of two to four questions each
The questions within any one group all relate to a single situation.
Five possible answer choices are given before the question.
An answer choice can be used once, more than once, or not at all in each group.
Part B:
Last 62 or 63 questions
Each question has five possible answer choice with one correct answer.
Some questions may be in groups of two or three.
Topics
Scoring
The test had 75 multiple choice questions that were to be answered in one hour. All questions had f
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What does all matter consist of?
A. oxygen
B. atoms
C. helium
D. carbon
Answer:
|
|
sciq-3863
|
multiple_choice
|
What do all sound waves begin with?
|
[
"vibrating matter",
"talking matter",
"oscillating matter",
"enclosing matter"
] |
A
|
Relavent Documents:
Document 0:::
This is a list of wave topics.
0–9
21 cm line
A
Abbe prism
Absorption spectroscopy
Absorption spectrum
Absorption wavemeter
Acoustic wave
Acoustic wave equation
Acoustics
Acousto-optic effect
Acousto-optic modulator
Acousto-optics
Airy disc
Airy wave theory
Alfvén wave
Alpha waves
Amphidromic point
Amplitude
Amplitude modulation
Animal echolocation
Antarctic Circumpolar Wave
Antiphase
Aquamarine Power
Arrayed waveguide grating
Artificial wave
Atmospheric diffraction
Atmospheric wave
Atmospheric waveguide
Atom laser
Atomic clock
Atomic mirror
Audience wave
Autowave
Averaged Lagrangian
B
Babinet's principle
Backward wave oscillator
Bandwidth-limited pulse
beat
Berry phase
Bessel beam
Beta wave
Black hole
Blazar
Bloch's theorem
Blueshift
Boussinesq approximation (water waves)
Bow wave
Bragg diffraction
Bragg's law
Breaking wave
Bremsstrahlung, Electromagnetic radiation
Brillouin scattering
Bullet bow shockwave
Burgers' equation
Business cycle
C
Capillary wave
Carrier wave
Cherenkov radiation
Chirp
Ernst Chladni
Circular polarization
Clapotis
Closed waveguide
Cnoidal wave
Coherence (physics)
Coherence length
Coherence time
Cold wave
Collimated light
Collimator
Compton effect
Comparison of analog and digital recording
Computation of radiowave attenuation in the atmosphere
Continuous phase modulation
Continuous wave
Convective heat transfer
Coriolis frequency
Coronal mass ejection
Cosmic microwave background radiation
Coulomb wave function
Cutoff frequency
Cutoff wavelength
Cymatics
D
Damped wave
Decollimation
Delta wave
Dielectric waveguide
Diffraction
Direction finding
Dispersion (optics)
Dispersion (water waves)
Dispersion relation
Dominant wavelength
Doppler effect
Doppler radar
Douglas Sea Scale
Draupner wave
Droplet-shaped wave
Duhamel's principle
E
E-skip
Earthquake
Echo (phenomenon)
Echo sounding
Echolocation (animal)
Echolocation (human)
Eddy (fluid dynamics)
Edge wave
Eikonal equation
Ekman layer
Ekman spiral
Ekman transport
El Niño–Southern Oscillation
El
Document 1:::
Particle displacement or displacement amplitude is a measurement of distance of the movement of a sound particle from its equilibrium position in a medium as it transmits a sound wave.
The SI unit of particle displacement is the metre (m). In most cases this is a longitudinal wave of pressure (such as sound), but it can also be a transverse wave, such as the vibration of a taut string. In the case of a sound wave travelling through air, the particle displacement is evident in the oscillations of air molecules with, and against, the direction in which the sound wave is travelling.
A particle of the medium undergoes displacement according to the particle velocity of the sound wave traveling through the medium, while the sound wave itself moves at the speed of sound, equal to in air at .
Mathematical definition
Particle displacement, denoted δ, is given by
where v is the particle velocity.
Progressive sine waves
The particle displacement of a progressive sine wave is given by
where
is the amplitude of the particle displacement;
is the phase shift of the particle displacement;
is the angular wavevector;
is the angular frequency.
It follows that the particle velocity and the sound pressure along the direction of propagation of the sound wave x are given by
where
is the amplitude of the particle velocity;
is the phase shift of the particle velocity;
is the amplitude of the acoustic pressure;
is the phase shift of the acoustic pressure.
Taking the Laplace transforms of v and p with respect to time yields
Since , the amplitude of the specific acoustic impedance is given by
Consequently, the amplitude of the particle displacement is related to those of the particle velocity and the sound pressure by
See also
Sound
Sound particle
Particle velocity
Particle acceleration
Document 2:::
Acoustic waves are a type of energy propagation through a medium by means of adiabatic loading and unloading. Important quantities for describing acoustic waves are acoustic pressure, particle velocity, particle displacement and acoustic intensity. Acoustic waves travel with a characteristic acoustic velocity that depends on the medium they're passing through. Some examples of acoustic waves are audible sound from a speaker (waves traveling through air at the speed of sound), seismic waves (ground vibrations traveling through the earth), or ultrasound used for medical imaging (waves traveling through the body).
Wave properties
Acoustic wave is a mechanical wave that transmits energy through the movements of atoms and molecules. Acoustic wave transmits through liquids in longitudinal manner (movement of particles are parallel to the direction of propagation of the wave); in contrast to electromagnetic wave that transmits in transverse manner (movement of particles at a right angle to the direction of propagation of the wave). However, in solids, acoustic wave transmits in both longitudinal and transverse manners due to presence of shear moduli in such a state of matter.
Acoustic wave equation
The acoustic wave equation describes the propagation of sound waves. The acoustic wave equation for sound pressure in one dimension is given by
where
is sound pressure in Pa
is position in the direction of propagation of the wave, in m
is speed of sound in m/s
is time in s
The wave equation for particle velocity has the same shape and is given by
where
is particle velocity in m/s
For lossy media, more intricate models need to be applied in order to take into account frequency-dependent attenuation and phase speed. Such models include acoustic wave equations that incorporate fractional derivative terms, see also the acoustic attenuation article.
D'Alembert gave the general solution for the lossless wave equation. For sound pressure, a solution would be
where
is angu
Document 3:::
Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics technology may be called an acoustical engineer. The application of acoustics is present in almost all aspects of modern society with the most obvious being the audio and noise control industries.
Hearing is one of the most crucial means of survival in the animal world and speech is one of the most distinctive characteristics of human development and culture. Accordingly, the science of acoustics spreads across many facets of human society—music, medicine, architecture, industrial production, warfare and more. Likewise, animal species such as songbirds and frogs use sound and hearing as a key element of mating rituals or for marking territories. Art, craft, science and technology have provoked one another to advance the whole, as in many other fields of knowledge. Robert Bruce Lindsay's "Wheel of Acoustics" is a well accepted overview of the various fields in acoustics.
History
Etymology
The word "acoustic" is derived from the Greek word ἀκουστικός (akoustikos), meaning "of or for hearing, ready to hear" and that from ἀκουστός (akoustos), "heard, audible", which in turn derives from the verb ἀκούω(akouo), "I hear".
The Latin synonym is "sonic", after which the term sonics used to be a synonym for acoustics and later a branch of acoustics. Frequencies above and below the audible range are called "ultrasonic" and "infrasonic", respectively.
Early research in acoustics
In the 6th century BC, the ancient Greek philosopher Pythagoras wanted to know why some combinations of musical sounds seemed more beautiful than others, and he found answers in terms of numerical ratios representing the harmonic overtone series on a string. He is reputed to have observed that when the length
Document 4:::
In physics, a mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium. While waves can move over long distances, the movement of the medium of transmission—the material—is limited. Therefore, the oscillating material does not move far from its initial equilibrium position. Mechanical waves can be produced only in media which possess elasticity and inertia. There are three types of mechanical waves: transverse waves, longitudinal waves, and surface waves. Some of the most common examples of mechanical waves are water waves, sound waves, and seismic waves.
Like all waves, mechanical waves transport energy. This energy propagates in the same direction as the wave. A wave requires an initial energy input; once this initial energy is added, the wave travels through the medium until all its energy is transferred. In contrast, electromagnetic waves require no medium, but can still travel through one.
Transverse wave
A transverse wave is the form of a wave in which particles of medium vibrate about their mean position perpendicular to the direction of the motion of the wave.
To see an example, move an end of a Slinky (whose other end is fixed) to the left-and-right of the Slinky, as opposed to to-and-fro. Light also has properties of a transverse wave, although it is an electromagnetic wave.
Longitudinal wave
Longitudinal waves cause the medium to vibrate parallel to the direction of the wave. It consists of multiple compressions and rarefactions. The rarefaction is the farthest distance apart in the longitudinal wave and the compression is the closest distance together. The speed of the longitudinal wave is increased in higher index of refraction, due to the closer proximity of the atoms in the medium that is being compressed. Sound is a longitudinal wave.
Surface waves
This type of wave travels along the surface or interface between two media. An example of a surface wave would be waves in a pool, or in an ocean
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What do all sound waves begin with?
A. vibrating matter
B. talking matter
C. oscillating matter
D. enclosing matter
Answer:
|
|
sciq-9579
|
multiple_choice
|
Some viruses carry a few viral enzyme molecules within their what?
|
[
"capsids",
"plastids",
"hormones",
"DNA"
] |
A
|
Relavent Documents:
Document 0:::
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 11,000 of the millions of virus species have been described in detail. The study of viruses is known as virology, a subspeciality of microbiology.
When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent viral particles, or virions, consisting of (i) genetic material, i.e., long molecules of DNA or RNA that encode the structure of the proteins by which the virus acts; (ii) a protein coat, the capsid, which surrounds and protects the genetic material; and in some cases (iii) an outside envelope of lipids. The shapes of these virus particles range from simple helical and icosahedral forms to more complex structures. Most virus species have virions too small to be seen with an optical microscope and are one-hundredth the size of most bacteria.
The origins of viruses in the evolutionary history of life are unclear: some may have evolved from plasmids—pieces of DNA that can move between cells—while others may have evolved from bacteria. In evolution, viruses are an important means of horizontal gene transfer, which increases genetic diversity in a way analogous to sexual reproduction. Viruses are considered by some biologists to be a life form, because they carry genetic material, reproduce, and evolve through natural selection, although they lack the key characteristics, such as cell structure, that are generally
Document 1:::
The term viral protein refers to both the products of the genome of a virus and any host proteins incorporated into the viral particle. Viral proteins are grouped according to their functions, and groups of viral proteins include structural proteins, nonstructural proteins, regulatory proteins, and accessory proteins. Viruses are non-living and do not have the means to reproduce on their own, instead depending on their host cell's machinery to do this. Thus, viruses do not code for most of the proteins required for their replication and the translation of their mRNA into viral proteins, but use proteins encoded by the host cell for this purpose.
Viral structural proteins
Most viral structural proteins are components for the capsid and the envelope of the virus.
Capsid
The genetic material of a virus is stored within a viral protein structure called the capsid. The capsid is a "shield" that protects the viral nucleic acids from getting degraded by host enzymes or other types of pesticides or pestilences. It also functions to attach the virion to its host, and enable the virion to penetrate the host cell membrane. Many copies of a single viral protein or a number of different viral proteins make up the capsid, and each of these viral proteins are coded for by one gene from the viral genome. The structure of the capsid allows the virus to use a small number of viral genes to make a large capsid.
Several protomers, oligomeric (viral) protein subunits, combine to form capsomeres, and capsomeres come together to form the capsid. Capsomeres can arrange into an icosahedral, helical, or complex capsid, but in many viruses, such as the herpes simplex virus, an icosahedral capsid is assembled. Three asymmetric and nonidentical viral protein units make up each of the twenty identical triangular faces in the icosahedral capsid.
Viral envelope
The capsid of some viruses are enclosed in a membrane called the viral envelope. In most cases, the viral envelope is obtained by
Document 2:::
The transmission of hepadnaviruses between their natural hosts, humans, non-human primates, and birds, including intra-species host transmission and cross-species transmission, is a topic of study in virology.
Hepadnaviruses are a family of viruses that can cause liver infections in humans and animals. They are Group VII viruses that possess double-stranded DNA genomes and replicate using reverse transcriptase. This unique replication strategy, combined with their extremely small genomes and a very narrow host and tissue tropism, has distinguished them enough to be classified in the family Hepadnaviridae. There are two recognized genera:
Orthohepadnavirus, type species: hepatitis B virus (HBV)
Avihepadnavirus, type species: duck hepatitis B virus (DHBV)
Structure
With the example of human HBV: the particular feature of the HBV structure is the presence of three different forms in the plasma of infected patients:
Dane particle (diameter ≈ 42 nm): the complete virion, which is infectious and consists of an enveloped icosahedral nucleocapsid containing the viral genome, consisting of core protein and protecting the partially double-stranded DNA genome, bounding with DNA polymerase. The capsid is enveloped by a lipid bilayer that contains three forms of envelope proteins: small (S) proteins, intermediated (M) proteins, and large (L) proteins, and these proteins have different surface antigenes domains which contribute the viral infectivity: L protein (Pre S1, Pre S2, S), M protein (Pre S2, S), S protein (S). In figure 1, showing the simplified structure of HBV particles.
Subviral sphere particles (diameter ≈ 22 nm), these smaller, non-infectious and are the most abundant particle in the blood of an infected one. They are assumed to have the ability of absorbing virus-neutralizing antibodies to facilitate the virus spread and maintenance in the host.
Filaments (diameter ≈ 22 nm, length: 50 nm-70 nm), which are less known about, but they are actually consisted of
Document 3:::
The capsomere is a subunit of the capsid, an outer covering of protein that protects the genetic material of a virus. Capsomeres self-assemble to form the capsid.
Subunits called protomers aggregate to form capsomeres. Various arrangements of capsomeres are: 1) Icosahedral, 2) Helical, and 3) Complex.
1) Icosahedral- An icosahedron is a polyhedron with 12 vertices and 20 faces. Two types of capsomeres constitute the icosahedral capsid: pentagonal (pentons) at the vertices and hexagonal (hexons) at the faces. There are always twelve pentons, but the number of hexons varies among virus groups. In electron micrographs, capsomeres are recognized as regularly spaced rings with a central hole.
2) Helical- The protomers are not grouped in capsomeres, but are bound to each other so as to form a ribbon-like structure. This structure folds into a helix because the protomers are thicker at one end than at the other. The diameter of the helical capsid is determined by characteristics of its protomers, while its length is determined by the length of the nucleic acid it encloses.
3) Complex- e.g., that exhibited by poxvirus and rhabdovirus. This group comprises all those viruses which do not fit into either of the above two groups.
When the viral particle has entered a host cell, the host cellular enzymes digest the capsid and its constituent capsomeres, thereby exposing the naked genetic material (DNA/RNA) of the virus, which subsequently enters the replication cycle.
The capsomeres protect against physical, chemical, and enzymatic damage and are multiply redundant; having a few protein subunits that are repeated. This is because the viral genome is being as economic as possible by only needing a few protein codons to make a large structure. One of the major functions of a capsid is to introduce the enclosed viral genome into host cells by adsorbing readily to host cell surfaces.
Document 4:::
Single particle analysis is a group of related computerized image processing techniques used to analyze images from transmission electron microscopy (TEM). These methods were developed to improve and extend the information obtainable from TEM images of particulate samples, typically proteins or other large biological entities such as viruses. Individual images of stained or unstained particles are very noisy, and so hard to interpret. Combining several digitized images of similar particles together gives an image with stronger and more easily interpretable features. An extension of this technique uses single particle methods to build up a three-dimensional reconstruction of the particle. Using cryo-electron microscopy it has become possible to generate reconstructions with sub-nanometer resolution and near-atomic resolution first in the case of highly symmetric viruses, and now in smaller, asymmetric proteins as well. Single particle analysis can also be performed by induced coupled plasma mass spectroscopy (ICP-MS).
Techniques
Single particle analysis can be done on both negatively stained and vitreous ice-embedded transmission electron cryomicroscopy (CryoTEM) samples. Single particle analysis methods are, in general, reliant on the sample being homogeneous, although techniques for dealing with conformational heterogeneity are being developed.
Images (micrographs) are taken with an electron microscope using charged-coupled device (CCD) detectors coupled to a phosphorescent layer (in the past, they were instead collected on film and digitized using high-quality scanners). The image processing is carried out using specialized software programs, often run on multi-processor computer clusters. Depending on the sample or the desired results, various steps of two- or three-dimensional processing can be done.
In addition, single particle analysis can also be performed in an individual particle mode using an ICP-MS unit.
Alignment and classification
Biological sampl
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Some viruses carry a few viral enzyme molecules within their what?
A. capsids
B. plastids
C. hormones
D. DNA
Answer:
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ai2_arc-914
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multiple_choice
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Which of these is an important safety rule to follow when using an electrical device?
|
[
"Wear an apron.",
"Keep work area dry.",
"Extinguish all flames.",
"Wear protective gloves."
] |
B
|
Relavent Documents:
Document 0:::
Infant and toddler safety are those actions and modifications put into place to keep babies and toddlers safe from accidental injury and death. Many accidents, injuries and deaths are preventable.
Infants begin to crawl around six to nine months of age. When they crawl, they are exposed to many dangers. Anticipating the development of the baby and toddler aids caregivers in identifying hazards before they are discovered by the child.
General recommendations
US government agencies recommend that caregivers take the following precautions:
Covering all unused electrical sockets with outlet plugs.
Keeping cords out of baby's reach. Tack up cords to vertical blinds and move furniture, lamps, or electronics to hide cords.
Securing furniture and electronics, such as bookcases and TVs, so they cannot be pulled down on top of the baby.
Using protective padding to cover sharp edges and corners, such as from a coffee table or fireplace hearth.
Installing safety gates at the bottom and top of stairwells or to block entry to unsafe rooms.
Using safety latches on cabinets and doors.
Storing all medicines, cleaning products, and other poisons out of the baby's reach.
Removing rubber tips from doorstops or replace with one-piece doorstops.
Looking for and removing all small objects. Objects that easily can pass through the center of a toilet paper roll might cause choking.
Keeping houseplants out of the baby's reach. Some plants can poison or make your babies sick.
Setting the water heater temperature to no higher than 125 degrees Fahrenheit. Water that is hotter can cause bad burns.
Closely supervising the baby around pets. Even family pets have been known to harm familiar children.
Furniture
Toddlers typically enjoy climbing up things with steps. This includes furniture. Heavy furniture in the home is often not secured to the wall. These pieces of furniture can include bookcases and dressers that can weigh hundreds of pounds. Heavy objects like televisions that
Document 1:::
CEBEC (; ) is a private Belgian rating label for the quality assurance of electrical appliances. Use of this label indicates that a piece of equipment conforms to European safety standards. The label is issued by SGS-CEBEC, now part of the SGS group. CEBEC has its own electrical testing laboratory located in Brussels. It is an approved laboratory for the purpose of certifications granted by SGS.
The laboratory was set up in 2002. In 2004 it was audited by an international team and at the end of 2004 the SGS CEBEC laboratory was approved as a CBTL (CB Testing Laboratory) under the international IECEE-CB scheme. In 2005, it was approved by EEPCA as a laboratory operating in compliance with the CCA, HAR and ENEC agreements.
Certification
The following Marks and Certifications can be obtained on the basis of testing performed in the SGS CEBEC laboratory:
CEBEC
Mark of compliance with Belgian safety standards. It is widely recognized in Europe and worldwide and generally equivalent to the European EN and International IEC Standards
IECEE/CB
International scheme for mutual acceptance of CB test reports and certification, based on IEC standards
ENEC
European mark for electrical equipment safety
ENEC+
European mark for performance of electrical equipment
CCA
European scheme for mutual acceptance of CCA test reports and certification, based on European standards
LOVAG
Agreement for electrical low-voltage equipment used in an industrial environment
HAR
European mark for electrical cables
Services
Product categories
Products for which certification services are available include:
CABL: electrical cable
CONT: automatic control equipment
HOUS: electrical household appliances
INST: installation equipment
ITAV: information technology Audio Video
MEAS: measuring equipment
MED: electro-medical equipment
OFF: information-processing equipment
POW: power equipment
PROT: protection equipment
SAFE: transformers
TRON: electronics household equipment
Sp
Document 2:::
Cleanliness suitability describes the suitability of operating materials and ventilation and air conditioning components for use in cleanrooms where the air cleanliness and other parameters are controlled by way of technical regulations. Tests are carried out to determine this.
Trends such as the miniaturization of structures as well as increased levels of reliability in technology, research and science require controlled “clean” manufacturing environments. The task of such environments is to minimize influences which could damage the products concerned. The cleanroom environments created by filtering the air were originally developed for the fields of microelectronics and microsystem technology but are now used in a wide range of other high technology sectors such as photovoltaics and the automotive industry.
Depending upon the industry and process concerned, different factors may have a damaging influence on a product, e.g.:
Particles, in microelectronics such as the semiconductor industry and especially biotic particles in life science industries such as pharmaceutics, bio-engineering and medical technology (cleanroom suitability)
Molecular contamination (outgassing), especially in microelectronics such as the semiconductor industry
Electrostatic discharge phenomena (ESD), especially in microelectronics such as the semiconductor industry
Resistance to cleaning and disinfection agents, especially in life science industries such as pharmaceutics
Surface interaction, especially in life science industries such as pharmaceutics, bio-engineering and medical technology
Cleanability, especially in life science industries such as pharmaceutics, bio-engineering and medical technology
Microbicidity, especially in life science industries such as pharmaceutics, bio-engineering and medical technology
The following factors may be responsible for contamination:
The cleanroom itself: Staff, although this is becoming less relevant as more and more staff are banned
Document 3:::
SQEP is an acronym for suitably qualified and experienced person.
The term is notably used in the UK nuclear power industry, see for example this safety management audit report from the Health and Safety Executive.
In the UK nuclear context, it is a standard requirement for licensed sites that "The licensee shall make and implement adequate arrangements to ensure that only suitably qualified and experienced persons
perform any duties which may affect the safety of operations on the site or any other duties assigned by or under these conditions or any arrangements required under these conditions.".
In this context the term is not restricted to professionally qualified personnel or to duties requiring significant technical expertise: any means any It is essential that all personnel whose activities have the potential to impact on nuclear safety are suitably qualified and experienced (SQEP) to carry out their jobs. This includes both those who directly carry out operations and others such as directors, managers, designers, safety case authors etc whose roles, if inadequately conceived or executed, may affect safety in less visible ways – for example, through introducing latent technical or organisational weaknesses. and conversely suitably means suitably, not particularly well: the Office of Nuclear Regulation takes SQEPness to be broadly equivalent to the International Atomic Energy Agency concept of 'competence' IAEA has defined competence as "the ability to put skills and knowledge into practice in order to perform a job in an effective and efficient manner to an established standard" ONR concurs with this definition, which is widely accepted within the international nuclear community. Other factors contributing to a person's competence include the person's prior experience, aptitudes, attitudes, behaviours, skills and qualifications.
In the context of UK nuclear licensing, the term "duly authorised person" (DAP) was extensively used for trained and experienc
Document 4:::
A biosafety cabinet (BSC)—also called a biological safety cabinet or microbiological safety cabinet—is an enclosed, ventilated laboratory workspace for safely working with materials contaminated with (or potentially contaminated with) pathogens requiring a defined biosafety level. Several different types of BSC exist, differentiated by the degree of biocontainment they provide. BSCs first became commercially available in 1950.
Purposes
The primary purpose of a BSC is to serve as a means to protect the laboratory worker and the surrounding environment from pathogens. All exhaust air is HEPA-filtered as it exits the biosafety cabinet, removing harmful bacteria and viruses. This is in contrast to a laminar flow clean bench, which blows unfiltered exhaust air towards the user and is not safe for work with pathogenic agents. Neither are most BSCs safe for use as fume hoods. Likewise, a fume hood fails to provide the environmental protection that HEPA filtration in a BSC would provide. However, most classes of BSCs have a secondary purpose to maintain the sterility of materials inside (the "product").
Classes
The U.S. Centers for Disease Control and Prevention (CDC) classifies BSCs into three classes. These classes and the types of BSCs within them are distinguished in two ways: the level of personnel and environmental protection provided and the level of product protection provided.
Class I
Class I cabinets provide personnel and environmental protection but no product protection. In fact, the inward flow of air can contribute to contamination of samples. Inward airflow is maintained at a minimum velocity of 75 ft/min(0.38 m/s). These BSCs are commonly used to enclose specific equipment (e.g. centrifuges) or procedures (e.g. aerating cultures) that potentially generate aerosols. BSCs of this class are either ducted (connected to the building exhaust system) or unducted (recirculating filtered exhaust back into the laboratory).
Class II
Class II cabinets provide bot
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Which of these is an important safety rule to follow when using an electrical device?
A. Wear an apron.
B. Keep work area dry.
C. Extinguish all flames.
D. Wear protective gloves.
Answer:
|
|
sciq-6241
|
multiple_choice
|
What type of mammals are humans?
|
[
"respiratory mammals",
"somatic mammals",
"marsupial mammals",
"placental mammals"
] |
D
|
Relavent Documents:
Document 0:::
In zoology, mammalogy is the study of mammals – a class of vertebrates with characteristics such as homeothermic metabolism, fur, four-chambered hearts, and complex nervous systems. Mammalogy has also been known as "mastology," "theriology," and "therology." The archive of number of mammals on earth is constantly growing, but is currently set at 6,495 different mammal species including recently extinct. There are 5,416 living mammals identified on earth and roughly 1,251 have been newly discovered since 2006. The major branches of mammalogy include natural history, taxonomy and systematics, anatomy and physiology, ethology, ecology, and management and control. The approximate salary of a mammalogist varies from $20,000 to $60,000 a year, depending on their experience. Mammalogists are typically involved in activities such as conducting research, managing personnel, and writing proposals.
Mammalogy branches off into other taxonomically-oriented disciplines such as primatology (study of primates), and cetology (study of cetaceans). Like other studies, mammalogy is also a part of zoology which is also a part of biology, the study of all living things.
Research purposes
Mammalogists have stated that there are multiple reasons for the study and observation of mammals. Knowing how mammals contribute or thrive in their ecosystems gives knowledge on the ecology behind it. Mammals are often used in business industries, agriculture, and kept for pets. Studying mammals habitats and source of energy has led to aiding in survival. The domestication of some small mammals has also helped discover several different diseases, viruses, and cures.
Mammalogist
A mammalogist studies and observes mammals. In studying mammals, they can observe their habitats, contributions to the ecosystem, their interactions, and the anatomy and physiology. A mammalogist can do a broad variety of things within the realm of mammals. A mammalogist on average can make roughly $58,000 a year. This dep
Document 1:::
Several universities have designed interdisciplinary courses with a focus on human biology at the undergraduate level. There is a wide variation in emphasis ranging from business, social studies, public policy, healthcare and pharmaceutical research.
Americas
Human Biology major at Stanford University, Palo Alto (since 1970)
Stanford's Human Biology Program is an undergraduate major; it integrates the natural and social sciences in the study of human beings. It is interdisciplinary and policy-oriented and was founded in 1970 by a group of Stanford faculty (Professors Dornbusch, Ehrlich, Hamburg, Hastorf, Kennedy, Kretchmer, Lederberg, and Pittendrigh). It is a very popular major and alumni have gone to post-graduate education, medical school, law, business and government.
Human and Social Biology (Caribbean)
Human and Social Biology is a Level 4 & 5 subject in the secondary and post-secondary schools in the Caribbean and is optional for the Caribbean Secondary Education Certification (CSEC) which is equivalent to Ordinary Level (O-Level) under the British school system. The syllabus centers on structure and functioning (anatomy, physiology, biochemistry) of human body and the relevance to human health with Caribbean-specific experience. The syllabus is organized under five main sections: Living organisms and the environment, life processes, heredity and variation, disease and its impact on humans, the impact of human activities on the environment.
Human Biology Program at University of Toronto
The University of Toronto offers an undergraduate program in Human Biology that is jointly offered by the Faculty of Arts & Science and the Faculty of Medicine. The program offers several major and specialist options in: human biology, neuroscience, health & disease, global health, and fundamental genetics and its applications.
Asia
BSc (Honours) Human Biology at All India Institute of Medical Sciences, New Delhi (1980–2002)
BSc (honours) Human Biology at AIIMS (New
Document 2:::
Animal science is described as "studying the biology of animals that are under the control of humankind". It can also be described as the production and management of farm animals. Historically, the degree was called animal husbandry and the animals studied were livestock species, like cattle, sheep, pigs, poultry, and horses. Today, courses available look at a broader area, including companion animals, like dogs and cats, and many exotic species. Degrees in Animal Science are offered at a number of colleges and universities. Animal science degrees are often offered at land-grant universities, which will often have on-campus farms to give students hands-on experience with livestock animals.
Education
Professional education in animal science prepares students for careers in areas such as animal breeding, food and fiber production, nutrition, animal agribusiness, animal behavior, and welfare. Courses in a typical Animal Science program may include genetics, microbiology, animal behavior, nutrition, physiology, and reproduction. Courses in support areas, such as genetics, soils, agricultural economics and marketing, legal aspects, and the environment also are offered.
Bachelor degree
At many universities, a Bachelor of Science (BS) degree in Animal Science allows emphasis in certain areas. Typical areas are species-specific or career-specific. Species-specific areas of emphasis prepare students for a career in dairy management, beef management, swine management, sheep or small ruminant management, poultry production, or the horse industry. Other career-specific areas of study include pre-veterinary medicine studies, livestock business and marketing, animal welfare and behavior, animal nutrition science, animal reproduction science, or genetics. Youth programs are also an important part of animal science programs.
Pre-veterinary emphasis
Many schools that offer a degree option in Animal Science also offer a pre-veterinary emphasis such as Iowa State University, th
Document 3:::
Mammals
Alces alces (Linnaeus, 1758) — Eurasian elk, moose
Axis axis (Erxleben, 1777) — chital, axis deer
Bison bison (Linnaeus, 1758) — American bison, buffalo
Capreolus capreolus (Linnaeus, 1758) — European roe deer, roe deer
Caracal caracal (Schreber, 1776) — caracal
Chinchilla chinchilla (Lichtenstein, 1829) — short-tailed chinchilla
Chiropotes chiropotes (Humboldt, 1811) — red-backed bearded saki
Cricetus cricetus (Linnaeus, 1758) — common hamster, European hamster
Crocuta crocuta (Erxleben, 1777) — spotted hyena
Dama dama (Linnaeus, 1758) — European fallow deer
Feroculus feroculus (Kelaart, 1850) — Kelaart's long-clawed shrew
Gazella gazella (Pallas, 1766) — mountain gazelle
Genetta genetta (Linnaeus, 1758) — common genet
Gerbillus gerbillus (Olivier, 1801) — lesser Egyptian gerbil
Giraffa giraffa (von Schreber, 1784) — southern giraffe
Glis glis (Linnaeus, 1766) — European edible dormouse, European fat dormouse
Gorilla gorilla (Savage, 1847) — western gorilla
Gulo gulo (Linnaeus, 1758) — wolverine
Hoolock hoolock (Harlan, 1834) — western hoolock gibbon
Hyaena hyaena (Linnaeus, 1758) — striped hyena
Indri indri (Gmelin, 1788) — indri
Jaculus jaculus (Linnaeus, 1758) — lesser Egyptian jerboa
Lagurus lagurus (Pallas, 1773) — steppe vole, steppe lemming
Lemmus lemmus (Linnaeus, 1758) — Norway lemming
Lutra lutra (Linnaeus, 1758) — European otter
Lynx lynx (Linnaeus, 1758) — Eurasian lynx
Macrophyllum macrophyllum (Schinz, 1821) — long-legged bat
Marmota marmota (Linnaeus, 1758) — Alpine marmot
Martes martes (Linnaeus, 1758) — European pine marten, pine marten
Meles meles (Linnaeus, 1758) — European badg
Document 4:::
The Human Animal: A Personal View of the Human Species is a British nature documentary series written and presented by English zoologist Desmond Morris, first transmitted on BBC One in the United Kingdom from 27 July to 31 August 1994. It was co-produced in association with Discovery Communications (later Warner Bros. Discovery) in the United States, as well as several public broadcasters include: ORF in Austria, various ARD networks (MDR, SFB and WDR) in Germany, and Teleac in the Netherlands.
The series was later repeated on BBC Knowledge between 29 November 2000 and 31 January 2002 – with the exception of its controversial fourth episode due to various erotic scenes with sexually explicit material.
Premise
The programme has been written to accompany its six-part television series made by the BBC's Natural History Unit in Bristol, owing a debt of gratitude to all members of the large team that made their enthusiasm for this project unflagging within the immense care and effort they took to recording various patterns of human behaviour all over the globe was ultimately inspiring.
It described as "a study of human behaviour from a zoological perspective", he travels the world to filming the diverse customs and habits of various regions while suggesting common roots. The series which took two years (between 1992 and 1993) to make, this time will be a fascinating controversial moment especially the filming of orgasm shots from inside a woman's body, standing upright on our human sexuality and the simple anatomical fact as Morris commented:
More than the mere fascination of finding out particularly in a cultural moment, making it easier to see those of other cultures, faiths, political beliefs or sexual orientation as so distinctly from us that we shared humanity, examining a different biological component of our behaviours and ways of being – a timeless reminder that shared far more than we think.
At the close of its first episode, Morris described through as it
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What type of mammals are humans?
A. respiratory mammals
B. somatic mammals
C. marsupial mammals
D. placental mammals
Answer:
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sciq-3399
|
multiple_choice
|
What type of friction is friction that acts on objects when they are sliding over a surface?
|
[
"rolling friction",
"spreading friction",
"static friction",
"sliding friction"
] |
D
|
Relavent Documents:
Document 0:::
Sliding is a type of motion between two surfaces in contact. This can be contrasted to rolling motion. Both types of motion may occur in bearings.
The relative motion or tendency toward such motion between two surfaces is resisted by friction. Friction may damage or "wear" the surfaces in contact. However, wear can be reduced by lubrication. The science and technology of friction, lubrication, and wear is known as tribology.
Sliding may occur between two objects of arbitrary shape, whereas rolling friction is the frictional force associated with the rotational movement of a somewhat disclike or other circular object along a surface. Generally, the frictional force of rolling friction is less than that associated with sliding kinetic friction. Typical values for the coefficient of rolling friction are less than that of sliding friction. Correspondingly sliding friction typically produces greater sound and thermal bi-products. One of the most common examples of sliding friction is the movement of braking motor vehicle tires on a roadway, a process which generates considerable heat and sound, and is typically taken into account in assessing the magnitude of roadway noise pollution.
Sliding friction
Sliding friction (also called kinetic friction) is a contact force that resists the sliding motion of two objects or an object and a surface. Sliding friction is almost always less than that of static friction; this is why it is easier to move an object once it starts moving rather than to get the object to begin moving from a rest position.
Where , is the force of kinetic friction. is the coefficient of kinetic friction, and N is the normal force.
Examples of sliding friction
Sledding
Pushing an object across a surface
Rubbing one's hands together (The friction force generates heat.)
A car sliding on ice
A car skidding as it turns a corner
Opening a window
Almost any motion where there is contact between an object and a surface
Falling down a bowling
Document 1:::
Slipperiness is when a surface has a low coefficient of friction, allowing objects to glide across the surface. People walking on slippery surfaces are likely to slip or fall. A surface can for example be slippery due to it being wet, or due to it being icy. There are several competing theories about why ice is slippery.
Road slipperiness is a major area of road safety, but various means have also been developed to measure walkway and deck slipperiness in order to develop health and safety standards.
See also
Floor slip resistance testing
Ice cleats, used to prevent slipping when walking on icy roads
Document 2:::
In mechanics, friction torque is the torque caused by the frictional force that occurs when two objects in contact move. Like all torques, it is a rotational force that may be measured in newton meters or pounds-feet.
Engineering
Friction torque can be disruptive in engineering. There are a variety of measures engineers may choose to take to eliminate these disruptions. Ball bearings are an example of an attempt to minimize the friction torque.
Friction torque can also be an asset in engineering. Bolts and nuts, or screws are often designed to be fastened with a given amount of torque, where the friction is adequate during use or operation for the bolt, nut, or screw to remain safely fastened. This is true with such applications as lug nuts retaining wheels to vehicles, or equipment subjected to vibration with sufficiently well-attached bolts, nuts, or screws to prevent the vibration from shaking them loose.
Examples
When a cyclist applies the brake to the forward wheel, the bicycle tips forward due to the frictional torque between the wheel and the ground.
When a golf ball hits the ground it begins to spin in part because of the friction torque applied to the golf ball from the friction between the golf ball and the ground.
See also
Torque
Force
Engineering
Mechanics
Moment (physics)
Document 3:::
The frictionless plane is a concept from the writings of Galileo Galilei. In his 1638 The Two New Sciences, Galileo presented a formula that predicted the motion of an object moving down an inclined plane. His formula was based upon his past experimentation with free-falling bodies. However, his model was not based upon experimentation with objects moving down an inclined plane, but from his conceptual modeling of the forces acting upon the object. Galileo understood the mechanics of the inclined plane as the combination of horizontal and vertical vectors; the result of gravity acting upon the object, diverted by the slope of the plane.
However, Galileo's equations do not contemplate friction, and therefore do not perfectly predict the results of an actual experiment. This is because some energy is always lost when one mass applies a non-zero normal force to another. Therefore, the observed speed, acceleration and distance traveled should be less than Galileo predicts. This energy is lost in forms like sound and heat. However, from Galileo's predictions of an object moving down an inclined plane in a frictionless environment, he created the theoretical foundation for extremely fruitful real-world experimental prediction.
Frictionless planes do not exist in the real world. However, if they did, one can be almost certain that objects on them would behave exactly as Galileo predicts. Despite their nonexistence, they have considerable value in the design of engines, motors, roadways, and even tow-truck beds, to name a few examples.
The effect of friction on an object moving down an inclined plane can be calculated as
where is the force of friction exerted by the object and the inclined plane on each other, parallel to the surface of the plane, is the normal force exerted by the object and the plane on each other, directed perpendicular to the plane, and is the coefficient of kinetic friction.
Unless the inclined plane is in a vacuum, a (usually) small amount of
Document 4:::
Stiction (a portmanteau of the words static and friction) is the force that needs to be overcome to enable relative motion of stationary objects in contact.
Any solid objects pressing against each other (but not sliding) will require some threshold of force parallel to the surface of contact in order to overcome static adhesion. Stiction is a threshold, not a continuous force. However, stiction might also be an illusion made by the rotation of kinetic friction.
In situations where two surfaces with areas below the micrometer scale come into close proximity (as in an accelerometer), they may adhere together. At this scale, electrostatic and/or Van der Waals and hydrogen bonding forces become significant. The phenomenon of two such surfaces being adhered together in this manner is also called stiction. Stiction may be related to hydrogen bonding or residual contamination.
Automobiles
Stiction is also the same threshold at which a rolling object would begin to slide over a surface rather than rolling at the expected rate (and in the case of a wheel, in the expected direction). In this case, it's called "rolling friction" or μr.
This is why driver training courses teach that, if a car begins to slide sideways, the driver should avoid braking and instead try to steer in the same direction as the slide. This gives the wheels a chance to regain static contact by rolling, which gives the driver some control again. Similarly, when trying to accelerate rapidly (particularly from a standing start) an overenthusiastic driver may "squeal" the driving wheels, but this impressive display of noise and smoke is less effective than maintaining static contact with the road. Many stunt-driving techniques (such as drifting) are done by deliberately breaking and/or regaining this rolling friction.
A car on a slippery surface can slide a long way with little control over orientation if the driver "locks" the wheels in stationary positions by pressing hard on the brakes. Anti-lock br
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What type of friction is friction that acts on objects when they are sliding over a surface?
A. rolling friction
B. spreading friction
C. static friction
D. sliding friction
Answer:
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|
sciq-11328
|
multiple_choice
|
Silicon and germanium react with nitrogen at high temperature to form what?
|
[
"carbonates",
"nitrides",
"oxides",
"isotopes"
] |
B
|
Relavent Documents:
Document 0:::
Computer science and engineering (CSE) is an academic program at many universities which comprises computer science classes (e.g. data structures and algorithms) and computer engineering classes (e.g computer architecture). There is no clear division in computing between science and engineering, just like in the field of materials science and engineering. CSE is also a term often used in Europe to translate the name of engineering informatics academic programs. It is offered in both undergraduate as well postgraduate with specializations.
Academic courses
Academic programs vary between colleges, but typically include a combination of topics in computer science, computer engineering, and electrical engineering. Undergraduate courses usually include programming, algorithms and data structures, computer architecture, operating systems, computer networks, parallel computing, embedded systems, algorithms design, circuit analysis and electronics, digital logic and processor design, computer graphics, scientific computing, software engineering, database systems, digital signal processing, virtualization, computer simulations and games programming. CSE programs also include core subjects of theoretical computer science such as theory of computation, numerical methods, machine learning, programming theory and paradigms. Modern academic programs also cover emerging computing fields like image processing, data science, robotics, bio-inspired computing, computational biology, autonomic computing and artificial intelligence. Most CSE programs require introductory mathematical knowledge, hence the first year of study is dominated by mathematical courses, primarily discrete mathematics, mathematical analysis, linear algebra, probability, and statistics, as well as the basics of electrical and electronic engineering, physics, and electromagnetism.
Example universities with CSE majors and departments
APJ Abdul Kalam Technological University
American International University-B
Document 1:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 2:::
The STEM (Science, Technology, Engineering, and Mathematics) pipeline is a critical infrastructure for fostering the development of future scientists, engineers, and problem solvers. It's the educational and career pathway that guides individuals from early childhood through to advanced research and innovation in STEM-related fields.
Description
The "pipeline" metaphor is based on the idea that having sufficient graduates requires both having sufficient input of students at the beginning of their studies, and retaining these students through completion of their academic program. The STEM pipeline is a key component of workplace diversity and of workforce development that ensures sufficient qualified candidates are available to fill scientific and technical positions.
The STEM pipeline was promoted in the United States from the 1970s onwards, as “the push for STEM (science, technology, engineering, and mathematics) education appears to have grown from a concern for the low number of future professionals to fill STEM jobs and careers and economic and educational competitiveness.”
Today, this metaphor is commonly used to describe retention problems in STEM fields, called “leaks” in the pipeline. For example, the White House reported in 2012 that 80% of minority groups and women who enroll in a STEM field switch to a non-STEM field or drop out during their undergraduate education. These leaks often vary by field, gender, ethnic and racial identity, socioeconomic background, and other factors, drawing attention to structural inequities involved in STEM education and careers.
Current efforts
The STEM pipeline concept is a useful tool for programs aiming at increasing the total number of graduates, and is especially important in efforts to increase the number of underrepresented minorities and women in STEM fields. Using STEM methodology, educational policymakers can examine the quantity and retention of students at all stages of the K–12 educational process and beyo
Document 3:::
A pre-STEM program is a course of study at any two-year college that prepares a student to transfer to a four-year school to earn a bachelor's degree in a STEM field.
Overview
The concept of a pre-STEM program is being developed to address America's need for more college-trained professionals in science, technology, engineering, and mathematics (STEM). It is an innovation meant to fill a gap at community colleges that do not have 'major' degree paths that students identify with on their way to earning an Associates degree. Students must complete a considerable amount of STEM coursework before transferring from a two-year school to a four-year school and earn a baccalaureate degree in a STEM field. Schools with a pre-STEM program are able to identify those students and support them with STEM-specific academic and career advising, increasing the student's chances of going on to earn a STEM baccalaureate degree in a timely fashion.
With over 50% of America's college-bound students starting their college career at public or private two-year school, and with a very small proportion of students who start college at a two-year school matriculating to and earning STEM degrees from four-year schools, pre-STEM programs have great potential for broadening participation in baccalaureate STEM studies.
Example programs
The effectiveness of pre-STEM programs is being investigated by a consortium of schools in Missouri: Moberly Area Community College, St. Charles Community College, Metropolitan Community College, and Truman State University.
A larger group of schools met at the Belknap Springs Meetings in October 2009 to discuss the challenges and opportunities presented by STEM-focused partnerships between 2-year and 4-year schools. Each program represented a two-year school and a four-year school that were trying to increase the number of people who earn a baccalaureate degree in a STEM area through various means, some of which were pre-STEM programs. Other methods includes
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The Hirst Research Centre, also known as the GEC Hirst Research Centre or GEC Research Laboratories, was established in 1919 at Wembley, Middlesex, by the General Electric Company.
History
Formally opened in 1923, the site at East Lane, Wembley was one of the first specialised industrial research laboratories to be built in Britain. The centre was named after Hugo Hirst, one of the founders of the company that would become the General Electric Company.
One of the centre's most famous achievements was the production of the cavity magnetron during World War II, the concept of which was established by Randall and Boot working at Birmingham University. Staff of the centre were also important in developing radars for use during the war. The 60 m radio mast at the back of the building became, along with Wembley Stadium, one of the landmarks of the area. Hirst was instrumental in setting up the National Grid system which provides power to the whole of the UK. The centre also worked on the design of electrical power systems for the British railway network.
In the 1990s the organisation moved to Borehamwood, Hertfordshire. After GEC left the Wembley site, it was used as the set for some scenes of the 1995 film The Young Poisoner's Handbook.
Notable Hirst employees and scientists
Clifford Paterson was the organisation's first director, and held that position until his death in 1948. Others working there included:
Derek Abbott
Jean Bacon
David Bevan
Colin Cherry
Robert James Clayton
Paul Hendricks
Cyril Hilsum
Daryl E. Hooper
Daniel McCaughan
Sanjay Jha
Bernard de Neumann
Clifford Copland Paterson
Michael Pepper
Derek Roberts
Bruce Robertson
Michael John Smith
Boris Townsend
Ian Robert Young
See also
Marconi Research Centre
GEC-Marconi scientist deaths conspiracy theory
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Silicon and germanium react with nitrogen at high temperature to form what?
A. carbonates
B. nitrides
C. oxides
D. isotopes
Answer:
|
|
sciq-8724
|
multiple_choice
|
What is the common term for single-celled fungi?
|
[
"prokaryotes",
"mushrooms",
"yeasts",
"sponges"
] |
C
|
Relavent Documents:
Document 0:::
Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defining feature of this fungal group is the "ascus" (), a microscopic sexual structure in which nonmotile spores, called ascospores, are formed. However, some species of the Ascomycota are asexual, meaning that they do not have a sexual cycle and thus do not form asci or ascospores. Familiar examples of sac fungi include morels, truffles, brewers' and bakers' yeast, dead man's fingers, and cup fungi. The fungal symbionts in the majority of lichens (loosely termed "ascolichens") such as Cladonia belong to the Ascomycota.
Ascomycota is a monophyletic group (it contains all descendants of one common ancestor). Previously placed in the Deuteromycota along with asexual species from other fungal taxa, asexual (or anamorphic) ascomycetes are now identified and classified based on morphological or physiological similarities to ascus-bearing taxa, and by phylogenetic analyses of DNA sequences.
The ascomycetes are of particular use to humans as sources of medicinally important compounds, such as antibiotics, for fermenting bread, alcoholic beverages and cheese. Penicillium species on cheeses and those producing antibiotics for treating bacterial infectious diseases are examples of ascomycetes.
Many ascomycetes are pathogens, both of animals, including humans, and of plants. Examples of ascomycetes that can cause infections in humans include Candida albicans, Aspergillus niger and several tens of species that cause skin infections. The many plant-pathogenic ascomycetes include apple scab, rice blast, the ergot fungi, black knot, and the powdery mildews. Another pathogenic ascomycete is Cordyceps. Cordyceps are parasites of insects and other arthropods. They are entomopathogenic fungi, which means the fungi kills or severely injures the
Document 1:::
Plectenchyma (from Greek πλέκω pleko 'I weave' and ἔγχυμα enchyma 'infusion', i.e., 'a woven tissue') is the general term employed to designate all types of fungal tissues.
The two most common types of tissues are prosenchyma and pseudoparenchyma.
The hyphae specifically become fused together.
Notes
Fungal morphology and anatomy
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The following outline is provided as an overview of and topical guide to fungi and mycology:
Fungi – "Fungi" is plural for "fungus". A fungus is any member of the group of eukaryotic organisms that includes unicellular microorganisms such as yeasts and molds, as well as multicellular fungi that produce familiar fruiting forms known as mushrooms. Biologists classify these organisms as a kingdom, Fungi, the second highest taxonomic rank of living organism beneath the Eukaryota domain; other kingdoms include plants, animals, protists, and bacteria. One difference that places fungi in a different kingdom is that their cell walls contain chitin, unlike the cell walls of plants, bacteria and some protists. Similar to animals, fungi are heterotrophs, that is, they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Growth is their means of mobility, except for spores (a few of which are flagellated), which may travel through air or water. Fungi function as the principal decomposers in ecological systems.
Types of fungi
By form
Molds
Aspergillus (list)
Fusarium (list)
Mushrooms
Agaricus (list)
Amanita (list)
Armillaria (list)
Boletus (list)
Coprinellus (list)
Coprinopsis (list)
Cortinarius (list)
Entoloma (list)
Gymnopilus (list)
Gymnopus (list)
Hebeloma (list)
Hygrocybe (list)
Hygrophorus (list)
Inocybe (list)
Lactarius (list)
Lactifluus (list)
Lepiota (list)
Leucoagaricus (list)
Leccinum (list)
Marasmius (list)
Pleurotus (list)
Yeasts
Other
Cyathus (list)
By activity
Carnivorous fungi
Pathogenic fungi
Poisonous fungi
Poisonous mushrooms
List of poisonous mushrooms
List of deadly mushrooms
By aspect
Bioluminescent fungi
Deadly fungi
By use
Medicinal fungi
Edible fungi
Edible molds
Penicillium camemberti – used in the production of Brie cheese and Camembert cheese
Penicillium glaucum – used in making Gorgonzola cheese
Penicillium roqueforti – used in making Roq
Document 3:::
A fungus (: fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as one of the traditional eukaryotic kingdoms, along with Animalia, Plantae and either Protista or Protozoa and Chromista.
A characteristic that places fungi in a different kingdom from plants, bacteria, and some protists is chitin in their cell walls. Fungi, like animals, are heterotrophs; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesize. Growth is their means of mobility, except for spores (a few of which are flagellated), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. These and other differences place fungi in a single group of related organisms, named the Eumycota (true fungi or Eumycetes), that share a common ancestor (i.e. they form a monophyletic group), an interpretation that is also strongly supported by molecular phylogenetics. This fungal group is distinct from the structurally similar myxomycetes (slime molds) and oomycetes (water molds). The discipline of biology devoted to the study of fungi is known as mycology (from the Greek , mushroom). In the past mycology was regarded as a branch of botany, although it is now known that fungi are genetically more closely related to animals than to plants.
Abundant worldwide, most fungi are inconspicuous because of the small size of their structures, and their cryptic lifestyles in soil or on dead matter. Fungi include symbionts of plants, animals, or other fungi and also parasites. They may become noticeable when fruiting, either as mushrooms or as molds. Fungi perform an essential role in the decomposition of organic matter and have fundamental roles in nutrient cycling and exchange in the environment. They have long been used as a direct source of h
Document 4:::
Fungal Genetics and Biology is a peer-reviewed scientific journal established in 1977 as Experimental Mycology, obtaining its current title in 1996. It covers experimental investigations of fungi and their traditional allies that relate structure and function to growth, reproduction, morphogenesis, and differentiation.
External links
Elsevier academic journals
English-language journals
Monthly journals
Mycology journals
Academic journals established in 1977
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What is the common term for single-celled fungi?
A. prokaryotes
B. mushrooms
C. yeasts
D. sponges
Answer:
|
|
sciq-8754
|
multiple_choice
|
What physical process occurs when large chunks of food are broken down into smaller pieces?
|
[
"chemical digestion",
"mechanical digestion",
"peristalsis",
"swallowing"
] |
B
|
Relavent Documents:
Document 0:::
Digestion is the breakdown of large insoluble food compounds into small water-soluble components so that they can be absorbed into the blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion. The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. Mechanical digestion takes place in the mouth through mastication and in the small intestine through segmentation contractions. In chemical digestion, enzymes break down food into the small compounds that the body can use.
In the human digestive system, food enters the mouth and mechanical digestion of the food starts by the action of mastication (chewing), a form of mechanical digestion, and the wetting contact of saliva. Saliva, a liquid secreted by the salivary glands, contains salivary amylase, an enzyme which starts the digestion of starch in the food; the saliva also contains mucus, which lubricates the food, and hydrogen carbonate, which provides the ideal conditions of pH (alkaline) for amylase to work, and electrolytes (Na+, K+, Cl−, HCO−3). About 30% of starch is hydrolyzed into disaccharide in the oral cavity (mouth). After undergoing mastication and starch digestion, the food will be in the form of a small, round slurry mass called a bolus. It will then travel down the esophagus and into the stomach by the action of peristalsis. Gastric juice in the stomach starts protein digestion. Gastric juice mainly contains hydrochloric acid and pepsin. In infants and toddlers, gastric juice also contains rennin to digest milk proteins. As the first two chemicals may damage the stomach wall, mucus and bicarbonates are secreted by the stomach. They provide a slimy layer that acts as a shield against the damag
Document 1:::
Food science is the basic science and applied science of food; its scope starts at overlap with agricultural science and nutritional science and leads through the scientific aspects of food safety and food processing, informing the development of food technology.
Food science brings together multiple scientific disciplines. It incorporates concepts from fields such as chemistry, physics, physiology, microbiology, and biochemistry. Food technology incorporates concepts from chemical engineering, for example.
Activities of food scientists include the development of new food products, design of processes to produce these foods, choice of packaging materials, shelf-life studies, sensory evaluation of products using survey panels or potential consumers, as well as microbiological and chemical testing. Food scientists may study more fundamental phenomena that are directly linked to the production of food products and its properties.
Definition
The Institute of Food Technologists defines food science as "the discipline in which the engineering, biological, and physical sciences are used to study the nature of foods, the causes of deterioration, the principles underlying food processing, and the improvement of foods for the consuming public". The textbook Food Science defines food science in simpler terms as "the application of basic sciences and engineering to study the physical, chemical, and biochemical nature of foods and the principles of food processing".
Disciplines
Some of the subdisciplines of food science are described below.
Food chemistry
Food chemistry is the study of chemical processes and interactions of all biological and non-biological components of foods. The biological substances include such items as meat, poultry, lettuce, beer, and milk.
It is similar to biochemistry in its main components such as carbohydrates, lipids, and protein, but it also includes areas such as water, vitamins, minerals, enzymes, food additives, flavors, and colors. This
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Food and biological process engineering is a discipline concerned with applying principles of engineering to the fields of food production and distribution and biology. It is a broad field, with workers fulfilling a variety of roles ranging from design of food processing equipment to genetic modification of organisms. In some respects it is a combined field, drawing from the disciplines of food science and biological engineering to improve the earth's food supply.
Creating, processing, and storing food to support the world's population requires extensive interdisciplinary knowledge. Notably, there are many biological engineering processes within food engineering to manipulate the multitude of organisms involved in our complex food chain. Food safety in particular requires biological study to understand the microorganisms involved and how they affect humans. However, other aspects of food engineering, such as food storage and processing, also require extensive biological knowledge of both the food and the microorganisms that inhabit it. This food microbiology and biology knowledge becomes biological engineering when systems and processes are created to maintain desirable food properties and microorganisms while providing mechanisms for eliminating the unfavorable or dangerous ones.
Concepts
Many different concepts are involved in the field of food and biological process engineering. Below are listed several major ones.
Food science
The science behind food and food production involves studying how food behaves and how it can be improved. Researchers analyze longevity and composition (i.e., ingredients, vitamins, minerals, etc.) of foods, as well as how to ensure food safety.
Genetic engineering
Modern food and biological process engineering relies heavily on applications of genetic manipulation. By understanding plants and animals on the molecular level, scientists are able to engineer them with specific goals in mind.
Among the most notable applications of
Document 3:::
Food physical chemistry is considered to be a branch of Food chemistry concerned with the study of both physical and chemical interactions in foods in terms of physical and chemical principles applied to food systems, as well as the applications of physical/chemical techniques and instrumentation for the study of foods. This field encompasses the "physiochemical principles of the reactions and conversions that occur during the manufacture, handling, and storage of foods."
Food physical chemistry concepts are often drawn from rheology, theories of transport phenomena, physical and chemical thermodynamics, chemical bonds and interaction forces, quantum mechanics and reaction kinetics, biopolymer science, colloidal interactions, nucleation, glass transitions, and freezing, disordered/noncrystalline solids.
Techniques utilized range widely from dynamic rheometry, optical microscopy, electron microscopy, AFM, light scattering, X-ray diffraction/neutron diffraction, to MRI, spectroscopy (NMR, FT-NIR/IR, NIRS, ESR and EPR, CD/VCD, Fluorescence, FCS, HPLC, GC-MS, and other related analytical techniques.
Understanding food processes and the properties of foods requires a knowledge of physical chemistry and how it applies to specific foods and food processes. Food physical chemistry is essential for improving the quality of foods, their stability, and food product development. Because food science is a multi-disciplinary field, food physical chemistry is being developed through interactions with other areas of food chemistry and food science, such as food analytical chemistry, food process engineering/food processing, food and bioprocess technology, food extrusion, food quality control, food packaging, food biotechnology, and food microbiology.
Topics in Food physical chemistry
The following are examples of topics in food physical chemistry that are of interest to both the food industry and food science:
Water in foods
Local structure in liquid water
Micro-crystalliz
Document 4:::
Artificial digestion is a laboratory technique that reduces food to protein, fat, carbohydrates, fiber, minerals, vitamins, and non-nutrient compounds for analytical or research purposes. Digestive agents such as pepsin and hydrochloric acid are typically used to accomplish artificial digestion.
Meat inspection
Artificial digestion is used to detect the presence of encysted trichinella larvae in suspected muscle tissue. Prior to this method, a sample of muscle tissue was compressed to visually express the encysted parasite. Using artificial digestion, meat samples are dissolved by a digestive solution and the remains are examined for the presence of larvae.
Digestion research
Artificial stomach and small intestine models are used instead of laboratory animals or human test subjects. Various models, from static one-compartment to dynamic multicompartment, exist. These models are used to study food digestion and subsequent bioavailability.
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What physical process occurs when large chunks of food are broken down into smaller pieces?
A. chemical digestion
B. mechanical digestion
C. peristalsis
D. swallowing
Answer:
|
|
sciq-10324
|
multiple_choice
|
Particles of matter have the most definite shape in what material state?
|
[
"plasma",
"liquid",
"gas",
"solid"
] |
D
|
Relavent Documents:
Document 0:::
States of matter are distinguished by changes in the properties of matter associated with external factors like pressure and temperature. States are usually distinguished by a discontinuity in one of those properties: for example, raising the temperature of ice produces a discontinuity at 0°C, as energy goes into a phase transition, rather than temperature increase. The three classical states of matter are solid, liquid and gas. In the 20th century, however, increased understanding of the more exotic properties of matter resulted in the identification of many additional states of matter, none of which are observed in normal conditions.
Low-energy states of matter
Classical states
Solid: A solid holds a definite shape and volume without a container. The particles are held very close to each other.
Amorphous solid: A solid in which there is no far-range order of the positions of the atoms.
Crystalline solid: A solid in which atoms, molecules, or ions are packed in regular order.
Plastic crystal: A molecular solid with long-range positional order but with constituent molecules retaining rotational freedom.
Quasicrystal: A solid in which the positions of the atoms have long-range order, but this is not in a repeating pattern.
Liquid: A mostly non-compressible fluid. Able to conform to the shape of its container but retains a (nearly) constant volume independent of pressure.
Liquid crystal: Properties intermediate between liquids and crystals. Generally, able to flow like a liquid but exhibiting long-range order.
Gas: A compressible fluid. Not only will a gas take the shape of its container but it will also expand to fill the container.
Modern states
Plasma: Free charged particles, usually in equal numbers, such as ions and electrons. Unlike gases, plasma may self-generate magnetic fields and electric currents and respond strongly and collectively to electromagnetic forces. Plasma is very uncommon on Earth (except for the ionosphere), although it is the mo
Document 1:::
Solid is one of the four fundamental states of matter along with liquid, gas, and plasma. The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural rigidity (as in rigid bodies) and resistance to a force applied to the surface. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire available volume like a gas. The atoms in a solid are bound to each other, either in a regular geometric lattice (crystalline solids, which include metals and ordinary ice), or irregularly (an amorphous solid such as common window glass). Solids cannot be compressed with little pressure whereas gases can be compressed with little pressure because the molecules in a gas are loosely packed.
The branch of physics that deals with solids is called solid-state physics, and is the main branch of condensed matter physics (which also includes liquids). Materials science is primarily concerned with the physical and chemical properties of solids. Solid-state chemistry is especially concerned with the synthesis of novel materials, as well as the science of identification and chemical composition.
Microscopic description
The atoms, molecules or ions that make up solids may be arranged in an orderly repeating pattern, or irregularly. Materials whose constituents are arranged in a regular pattern are known as crystals. In some cases, the regular ordering can continue unbroken over a large scale, for example diamonds, where each diamond is a single crystal. Solid objects that are large enough to see and handle are rarely composed of a single crystal, but instead are made of a large number of single crystals, known as crystallites, whose size can vary from a few nanometers to several meters. Such materials are called polycrystalline. Almost all common metals, and many ceramics, are polycrystalline.
In other materials, there is no long-range order in the
Document 2:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 3:::
A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a nearly constant volume independent of pressure. It is one of the four fundamental states of matter (the others being solid, gas, and plasma), and is the only state with a definite volume but no fixed shape.
The density of a liquid is usually close to that of a solid, and much higher than that of a gas. Therefore, liquid and solid are both termed condensed matter. On the other hand, as liquids and gases share the ability to flow, they are both called fluids.
A liquid is made up of tiny vibrating particles of matter, such as atoms, held together by intermolecular bonds. Like a gas, a liquid is able to flow and take the shape of a container. Unlike a gas, a liquid maintains a fairly constant density and does not disperse to fill every space of a container.
Although liquid water is abundant on Earth, this state of matter is actually the least common in the known universe, because liquids require a relatively narrow temperature/pressure range to exist. Most known matter in the universe is either gas (as interstellar clouds) or plasma (as stars).
Introduction
Liquid is one of the four primary states of matter, with the others being solid, gas and plasma. A liquid is a fluid. Unlike a solid, the molecules in a liquid have a much greater freedom to move. The forces that bind the molecules together in a solid are only temporary in a liquid, allowing a liquid to flow while a solid remains rigid.
A liquid, like a gas, displays the properties of a fluid. A liquid can flow, assume the shape of a container, and, if placed in a sealed container, will distribute applied pressure evenly to every surface in the container. If liquid is placed in a bag, it can be squeezed into any shape. Unlike a gas, a liquid is nearly incompressible, meaning that it occupies nearly a constant volume over a wide range of pressures; it does not generally expand to fill available space in a containe
Document 4:::
This is a list of topics that are included in high school physics curricula or textbooks.
Mathematical Background
SI Units
Scalar (physics)
Euclidean vector
Motion graphs and derivatives
Pythagorean theorem
Trigonometry
Motion and forces
Motion
Force
Linear motion
Linear motion
Displacement
Speed
Velocity
Acceleration
Center of mass
Mass
Momentum
Newton's laws of motion
Work (physics)
Free body diagram
Rotational motion
Angular momentum (Introduction)
Angular velocity
Centrifugal force
Centripetal force
Circular motion
Tangential velocity
Torque
Conservation of energy and momentum
Energy
Conservation of energy
Elastic collision
Inelastic collision
Inertia
Moment of inertia
Momentum
Kinetic energy
Potential energy
Rotational energy
Electricity and magnetism
Ampère's circuital law
Capacitor
Coulomb's law
Diode
Direct current
Electric charge
Electric current
Alternating current
Electric field
Electric potential energy
Electron
Faraday's law of induction
Ion
Inductor
Joule heating
Lenz's law
Magnetic field
Ohm's law
Resistor
Transistor
Transformer
Voltage
Heat
Entropy
First law of thermodynamics
Heat
Heat transfer
Second law of thermodynamics
Temperature
Thermal energy
Thermodynamic cycle
Volume (thermodynamics)
Work (thermodynamics)
Waves
Wave
Longitudinal wave
Transverse waves
Transverse wave
Standing Waves
Wavelength
Frequency
Light
Light ray
Speed of light
Sound
Speed of sound
Radio waves
Harmonic oscillator
Hooke's law
Reflection
Refraction
Snell's law
Refractive index
Total internal reflection
Diffraction
Interference (wave propagation)
Polarization (waves)
Vibrating string
Doppler effect
Gravity
Gravitational potential
Newton's law of universal gravitation
Newtonian constant of gravitation
See also
Outline of physics
Physics education
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Particles of matter have the most definite shape in what material state?
A. plasma
B. liquid
C. gas
D. solid
Answer:
|
|
sciq-9135
|
multiple_choice
|
What is the term for the development of an embryo inside an egg within the mother’s body until it hatches?
|
[
"pregnancy",
"spawning",
"ovovivipary",
"asexual reproduction"
] |
C
|
Relavent Documents:
Document 0:::
Human embryonic development, or human embryogenesis, is the development and formation of the human embryo. It is characterised by the processes of cell division and cellular differentiation of the embryo that occurs during the early stages of development. In biological terms, the development of the human body entails growth from a one-celled zygote to an adult human being. Fertilization occurs when the sperm cell successfully enters and fuses with an egg cell (ovum). The genetic material of the sperm and egg then combine to form the single cell zygote and the germinal stage of development commences. Embryonic development in the human, covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus.
The eight weeks has 23 stages.
Human embryology is the study of this development during the first eight weeks after fertilization. The normal period of gestation (pregnancy) is about nine months or 40 weeks.
The germinal stage refers to the time from fertilization through the development of the early embryo until implantation is completed in the uterus. The germinal stage takes around 10 days. During this stage, the zygote begins to divide, in a process called cleavage. A blastocyst is then formed and implants in the uterus. Embryogenesis continues with the next stage of gastrulation, when the three germ layers of the embryo form in a process called histogenesis, and the processes of neurulation and organogenesis follow.
In comparison to the embryo, the fetus has more recognizable external features and a more complete set of developing organs. The entire process of embryogenesis involves coordinated spatial and temporal changes in gene expression, cell growth and cellular differentiation. A nearly identical process occurs in other species, especially among chordates.
Germinal stage
Fertilization
Fertilization takes place when the spermatozoon has successfully entered the ovum and the two sets of genetic material carried b
Document 1:::
In developmental biology, animal embryonic development, also known as animal embryogenesis, is the developmental stage of an animal embryo. Embryonic development starts with the fertilization of an egg cell (ovum) by a sperm cell, (spermatozoon). Once fertilized, the ovum becomes a single diploid cell known as a zygote. The zygote undergoes mitotic divisions with no significant growth (a process known as cleavage) and cellular differentiation, leading to development of a multicellular embryo after passing through an organizational checkpoint during mid-embryogenesis. In mammals, the term refers chiefly to the early stages of prenatal development, whereas the terms fetus and fetal development describe later stages.
The main stages of animal embryonic development are as follows:
The zygote undergoes a series of cell divisions (called cleavage) to form a structure called a morula.
The morula develops into a structure called a blastula through a process called blastulation.
The blastula develops into a structure called a gastrula through a process called gastrulation.
The gastrula then undergoes further development, including the formation of organs (organogenesis).
The embryo then transforms into the next stage of development, the nature of which varies between different animal species (examples of possible next stages include a fetus and a larva).
Fertilization and the zygote
The egg cell is generally asymmetric, having an animal pole (future ectoderm).
It is covered with protective envelopes, with different layers. The first envelope – the one in contact with the membrane of the egg – is made of glycoproteins and is known as the vitelline membrane (zona pellucida in mammals). Different taxa show different cellular and acellular envelopes englobing the vitelline membrane.
Fertilization is the fusion of gametes to produce a new organism. In animals, the process involves a sperm fusing with an ovum, which eventually leads to the development of an embryo. Depen
Document 2:::
Development of the human body is the process of growth to maturity. The process begins with fertilization, where an egg released from the ovary of a female is penetrated by a sperm cell from a male. The resulting zygote develops through mitosis and cell differentiation, and the resulting embryo then implants in the uterus, where the embryo continues development through a fetal stage until birth. Further growth and development continues after birth, and includes both physical and psychological development that is influenced by genetic, hormonal, environmental and other factors. This continues throughout life: through childhood and adolescence into adulthood.
Before birth
Development before birth, or prenatal development () is the process in which a zygote, and later an embryo, and then a fetus develops during gestation. Prenatal development starts with fertilization and the formation of the zygote, the first stage in embryonic development which continues in fetal development until birth.
Fertilization
Fertilization occurs when the sperm successfully enters the ovum's membrane. The chromosomes of the sperm are passed into the egg to form a unique genome. The egg becomes a zygote and the germinal stage of embryonic development begins. The germinal stage refers to the time from fertilization, through the development of the early embryo, up until implantation. The germinal stage is over at about 10 days of gestation.
The zygote contains a full complement of genetic material with all the biological characteristics of a single human being, and develops into the embryo. Embryonic development has four stages: the morula stage, the blastula stage, the gastrula stage, and the neurula stage. Prior to implantation, the embryo remains in a protein shell, the zona pellucida, and undergoes a series of rapid mitotic cell divisions called cleavage. A week after fertilization the embryo still has not grown in size, but hatches from the zona pellucida and adheres to the lining o
Document 3:::
Embryonated, unembryonated and de-embryonated are terms generally used in reference to eggs or, in botany, to seeds. The words are often used as professional jargon rather than as universally applicable terms or concepts. Examples of relevant fields in which the words are useful include reproductive biology, virology, microbiology, parasitology, entomology, and poultry husbandry. Since the words are widely used in the various disciplines, there seems to be little present prospect of replacing them with universal, definitive, and distinct terms.
Meaning
The terms embryonated, unembryonated and de-embryonated respectively mean "having an embryo", "not having an embryo", and "having lost an embryo", and they most often refer to eggs. In Merriam-Webster the earliest known use of the term "embryonated" dates from 1687, while Oxford gives a reference dating from 1669.
Embryonate
The term embryonate can be used as an adjective to mean embryonated, or as a noun to mean one containing an embryo (e.g. "We selected only the embryonates and discarded the rest").
Embryonate can also be used as an intransitive verb meaning to develop an embryo (e.g. "In 2-4 weeks after deposition in soil, they embryonate if the soil conditions are suitable").
De-embryonate
De-embryonate refers to the removal of embryos from seeds or similar reproductive units, typically in physiological studies. As with embrionate, it can either be a verb, noun or adjective. In some contexts the term "embryonectomy" may be used. For example, loss of the embryo may result from the activity of seed predation by insects.
Usage
There often is confusion in applying the term to various classes of unfertilised eggs and trophic eggs, depending on the area of expertise.
Virology
In virology, eggs of domestic poultry are used for culturing viruses for research purposes. Viruses generally can propagate only in live cells, so only a fertilised egg with a good supply of growing embryonic tissue is useful. Practitioners
Document 4:::
Oogenesis, ovogenesis, or oögenesis is the differentiation of the ovum (egg cell) into a cell competent to further develop when fertilized. It is developed from the primary oocyte by maturation. Oogenesis is initiated in the embryonic stage.
Oogenesis in non-human mammals
In mammals, the first part of oogenesis starts in the germinal epithelium, which gives rise to the development of ovarian follicles, the functional unit of the ovary.
Oogenesis consists of several sub-processes: oocytogenesis, ootidogenesis, and finally maturation to form an ovum (oogenesis proper). Folliculogenesis is a separate sub-process that accompanies and supports all three oogenetic sub-processes.
Oogonium —(Oocytogenesis)—> Primary Oocyte —(Meiosis I)—> First Polar body (Discarded afterward) + Secondary oocyte —(Meiosis II)—> Second Polar Body (Discarded afterward) + Ovum
Oocyte meiosis, important to all animal life cycles yet unlike all other instances of animal cell division, occurs completely without the aid of spindle-coordinating centrosomes.
The creation of oogonia
The creation of oogonia traditionally doesn't belong to oogenesis proper, but, instead, to the common process of gametogenesis, which, in the female human, begins with the processes of folliculogenesis, oocytogenesis, and ootidogenesis. Oogonia enter meiosis during embryonic development, becoming oocytes. Meiosis begins with DNA replication and meiotic crossing over. It then stops in early prophase.
Maintenance of meiotic arrest
Mammalian oocytes are maintained in meiotic prophase arrest for a very long time—months in mice, years in humans. Initially the arrest is due to lack of sufficient cell cycle proteins to allow meiotic progression. However, as the oocyte grows, these proteins are synthesized, and meiotic arrest becomes dependent on cyclic AMP. The cyclic AMP is generated by the oocyte by adenylyl cyclase in the oocyte membrane. The adenylyl cyclase is kept active by a constitutively active G-protein-coupled
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What is the term for the development of an embryo inside an egg within the mother’s body until it hatches?
A. pregnancy
B. spawning
C. ovovivipary
D. asexual reproduction
Answer:
|
|
sciq-6224
|
multiple_choice
|
What type of proteins are only temporarily associated with the membrane?
|
[
"sensitive rod proteins",
"peripheral oxidation proteins",
"peripheral membrane proteins",
"visual membrane proteins"
] |
C
|
Relavent Documents:
Document 0:::
Membrane proteins are common proteins that are part of, or interact with, biological membranes. Membrane proteins fall into several broad categories depending on their location. Integral membrane proteins are a permanent part of a cell membrane and can either penetrate the membrane (transmembrane) or associate with one or the other side of a membrane (integral monotopic). Peripheral membrane proteins are transiently associated with the cell membrane.
Membrane proteins are common, and medically important—about a third of all human proteins are membrane proteins, and these are targets for more than half of all drugs. Nonetheless, compared to other classes of proteins, determining membrane protein structures remains a challenge in large part due to the difficulty in establishing experimental conditions that can preserve the correct conformation of the protein in isolation from its native environment.
Function
Membrane proteins perform a variety of functions vital to the survival of organisms:
Membrane receptor proteins relay signals between the cell's internal and external environments.
Transport proteins move molecules and ions across the membrane. They can be categorized according to the Transporter Classification database.
Membrane enzymes may have many activities, such as oxidoreductase, transferase or hydrolase.
Cell adhesion molecules allow cells to identify each other and interact. For example, proteins involved in immune response
The localization of proteins in membranes can be predicted reliably using hydrophobicity analyses of protein sequences, i.e. the localization of hydrophobic amino acid sequences.
Integral membrane proteins
Integral membrane proteins are permanently attached to the membrane. Such proteins can be separated from the biological membranes only using detergents, nonpolar solvents, or sometimes denaturing agents. They can be classified according to their relationship with the bilayer:
Integral polytopic proteins are transmembran
Document 1:::
Tight junctions, also known as occluding junctions or zonulae occludentes (singular, zonula occludens), are multiprotein junctional complexes whose canonical function is to prevent leakage of solutes and water and seals between the epithelial cells. They also play a critical role maintaining the structure and permeability of endothelial cells. Tight junctions may also serve as leaky pathways by forming selective channels for small cations, anions, or water. The corresponding junctions that occur in invertebrates are septate junctions.
Structure
Tight junctions are composed of a branching network of sealing strands, each strand acting independently from the others. Therefore, the efficiency of the junction in preventing ion passage increases exponentially with the number of strands.
Each strand is formed from a row of transmembrane proteins embedded in both plasma membranes, with extracellular domains joining one another directly. There are at least 40 different proteins composing the tight junctions. These proteins consist of both transmembrane and cytoplasmic proteins. The three major transmembrane proteins are occludin, claudins, and junction adhesion molecule (JAM) proteins. These associate with different peripheral membrane proteins such as ZO-1 located on the intracellular side of plasma membrane, which anchor the strands to the actin component of the cytoskeleton. Thus, tight junctions join together the cytoskeletons of adjacent cells.
Transmembrane proteins:
Occludin was the first integral membrane protein to be identified. It has a molecular weight of ~60kDa. It consists of four transmembrane domains and both the N-terminus and the C-terminus of the protein are intracellular. It forms two extracellular loops and one intracellular loop. These loops help regulate paracellular permeability. Occludin also plays a key role in cellular structure and barrier function.
Claudins were discovered after occludin and are a family of over 27 different members in
Document 2:::
Gap junctions are one of four broad categories of intercellular connections that form between a multitude of animal cell types. First photographed around 1952 it wasn't until 1969 that gap junctions were referred to as "gap junctions". Named after the 2-4 nm gap they bridged between cell membranes, they had been characterised in more detail by 1967.
Within a gap junction reside protein complexes, referred initially to as "globules", observed to connect one cell to another and also vesicles within a cell to the outer cell membrane. By 1974 one of the major gap junction proteins was dubbed a "connexin", and six connexins were observed to form a channels called a "connexon", due to the connections connexon pairs made between cells. The initial discovery of gap junctions in nerve cells lent credence to their function in transmission of electrical impulses. Experimental confirmation followed with molecules, ions and electrical impulses shown to pass through the connexons which proved to be a generalized regulated gate between cells in gap junctions. As a type of hemichannel connexons also form channels to the extracellular regions as well.
While more than 26 different connexins frequently populate gap junctions in various different tissues there are at least 12 other components that form the specialized area of membrane called the gap junction. These components include among others the tight junction protein ZO-1 that holds the membranes close together, sodium channels, and aquaporin.
With increasing ability to sequence the DNA of organisms the complexity of the gap junction family of proteins increased. The term connexin was used to describe the gap junction proteins connecting two cells with pores. Sequencing of these pore proteins showed them to be strucuturally similar between vertebrates and invertebrates but different in sequence. As a result the term "innexin" was used to differentiate invertebrate from vertebrate connexins. While sequencing of invertebrate sp
Document 3:::
The Society of General Physiologists (SGP) is a scientific organization whose purpose is to promote and disseminate knowledge in the field of general physiology, and otherwise to advance understanding and interest in the subject of general physiology. The Society’s main office is located at the Marine Biological Laboratory in Woods Hole, MA, where the society was founded in 1946. Past Presidents of the Society include Richard W. Aldrich, Richard W. Tsien, Clay Armstrong, and Andrew Szent-Gyorgi. The society's archives is held at the National Library of Medicine in Bethesda, Maryland.
Membership
The Society's international membership is made up of nearly 600 career physiologists who work in academia, government, and industry. Membership in the Society is open to any individual actively interested in the field of general physiology and who has made significant contributions to knowledge in that field. The Society has become known for promoting research in many subfields of cellular and molecular physiology, but especially in the fields of membrane transport and ion channels, cell membrane structure, regulation, and dynamics, and cellular contractility and molecular motors.
Activities
The major activity of the Society is its annual symposium, which is held at the Marine Biological Laboratory in Woods Hole, MA. Society of General Physiologists symposia cover the forefront of physiological research and are small enough to maximize discussion and interaction among both young and established investigators. Abstracts of the annual meeting are published in The Journal of General Physiology.
The 2015 symposium (September 16–20) topic is "Macromolecular Local Signaling Complexes." Detailed information regarding the scientific agenda and registration is provided at the symposium website:
https://web.archive.org/web/20150801070408/http://www.sgpweb.org/symposium2015.html
Recent past symposium topics include:
2014 Sensory Transduction
2013 The Enigmatic Chloride Ion: Tra
Document 4:::
Paracellular transport refers to the transfer of substances across an epithelium by passing through the intercellular space between the cells. It is in contrast to transcellular transport, where the substances travel through the cell, passing through both the apical membrane and basolateral membrane.
The distinction has particular significance in renal physiology and intestinal physiology. Transcellular transport often involves energy expenditure whereas paracellular transport is unmediated and passive down a concentration gradient, or by osmosis (for water) and solvent drag for solutes. Paracellular transport also has the benefit that absorption rate is matched to load because it has no transporters that can be saturated.
In most mammals, intestinal absorption of nutrients is thought to be dominated by transcellular transport, e.g., glucose is primarily absorbed via the SGLT1 transporter and other glucose transporters. Paracellular absorption therefore plays only a minor role in glucose absorption, although there is evidence that paracellular pathways become more available when nutrients are present in the intestinal lumen. In contrast, small flying vertebrates (small birds and bats) rely on the paracellular pathway for the majority of glucose absorption in the intestine. This has been hypothesized to compensate for an evolutionary pressure to reduce mass in flying animals, which resulted in a reduction in intestine size and faster transit time of food through the gut.
Capillaries of the blood–brain barrier have only transcellular transport, in contrast with normal capillaries which have both transcellular and paracellular transport.
The paracellular pathway of transport is also important for the absorption of drugs in the gastrointestinal tract. The paracellular pathway allows the permeation of hydrophilic molecules that are not able to permeate through the lipid membrane by the transcellular pathway of absorption. This is particularly important for hydrophi
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What type of proteins are only temporarily associated with the membrane?
A. sensitive rod proteins
B. peripheral oxidation proteins
C. peripheral membrane proteins
D. visual membrane proteins
Answer:
|
|
sciq-10882
|
multiple_choice
|
What type of switch automatically opens a circuit if too much current flows through it?
|
[
"regulator switch",
"kill switch",
"toggle switch",
"circuit breaker"
] |
D
|
Relavent Documents:
Document 0:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 1:::
Conditional short-circuit current is the value of the alternating current component of a prospective current, which a switch without integral short-circuit protection, but protected by a suitable short circuit protective device (SCPD) in series, can withstand for the operating time of the current under specified test conditions. It may be understood to be the RMS value of the maximum permissible current over a specified time interval (t0,t1) and operating conditions.
The IEC definition is critiqued to be open to interpretation.
Document 2:::
A pre-STEM program is a course of study at any two-year college that prepares a student to transfer to a four-year school to earn a bachelor's degree in a STEM field.
Overview
The concept of a pre-STEM program is being developed to address America's need for more college-trained professionals in science, technology, engineering, and mathematics (STEM). It is an innovation meant to fill a gap at community colleges that do not have 'major' degree paths that students identify with on their way to earning an Associates degree. Students must complete a considerable amount of STEM coursework before transferring from a two-year school to a four-year school and earn a baccalaureate degree in a STEM field. Schools with a pre-STEM program are able to identify those students and support them with STEM-specific academic and career advising, increasing the student's chances of going on to earn a STEM baccalaureate degree in a timely fashion.
With over 50% of America's college-bound students starting their college career at public or private two-year school, and with a very small proportion of students who start college at a two-year school matriculating to and earning STEM degrees from four-year schools, pre-STEM programs have great potential for broadening participation in baccalaureate STEM studies.
Example programs
The effectiveness of pre-STEM programs is being investigated by a consortium of schools in Missouri: Moberly Area Community College, St. Charles Community College, Metropolitan Community College, and Truman State University.
A larger group of schools met at the Belknap Springs Meetings in October 2009 to discuss the challenges and opportunities presented by STEM-focused partnerships between 2-year and 4-year schools. Each program represented a two-year school and a four-year school that were trying to increase the number of people who earn a baccalaureate degree in a STEM area through various means, some of which were pre-STEM programs. Other methods includes
Document 3:::
In electronics, an electronic switch is a switch controlled by an active electronic component or device. Without using moving parts, they are called solid state switches, which distinguishes them from mechanical switches.
Electronic switches are considered binary devices because they dramatically change the conductivity of a path in electrical circuit between two extremes when switching between their two states of on and off.
History
Many people use metonymy to call a variety of devices that conceptually connect or disconnect signals and communication paths between electrical devices as "switches", analogous to the way mechanical switches connect and disconnect paths for electrons to flow between two conductors.
The traditional relay is an electromechanical switch that uses an electromagnet controlled by a current to operate a mechanical switching mechanism. Other operating principles are also used (for instance, solid-state relays invented in 1971 control power circuits with no moving parts, instead using a semiconductor device to perform switching—often a silicon-controlled rectifier or triac).
Early telephone systems used an electromagnetically operated Strowger switch to connect telephone callers; later telephone exchanges contain one or more electromechanical crossbar switches. Thus the term 'switched' is applied to telecommunications networks, and signifies a network that is circuit switched, providing dedicated circuits for communication between end nodes, such as the public switched telephone network.
The term switch has since spread to a variety of digital active devices such as transistors and logic gates whose function is to change their output state between logic states or connect different signal lines.
The common feature of all these usages is they refer to devices that control a binary state of either on or off, closed or open, connected or not connected, conducting or not conducting, low impedance or high impedance.
Types
The diode can be t
Document 4:::
Supervisory circuits are electronic circuits that monitor one or more parameters of systems such as power supplies and microprocessors which must be maintained within certain limits, and take appropriate action if a parameter goes out of bounds, creating an unacceptable or dangerous situation.
Supervisory circuits are known by a variety of names, including battery monitors, power supply monitors, supply supervisory circuits, and reset circuits.
Thermal protection
A thermal protection circuit consists of a temperature-monitoring circuit and a control circuit. The control circuit may either shut down the circuitry it is protecting, reduce the power available in order to avoid overheating, or notify the system (software or user). These circuits may be quite complex, programmable and software-run, or simple with predefined limits.
Overvoltage and undervoltage protection
Voltage protection circuits protect circuitry from either overvoltage or undervoltage; either of these situations can have detrimental effects. Supervisory circuits that specifically focus on voltage regulation are often sold as supply voltage supervisors and will reset the protected circuit when the voltage returns to operating range.
Two types of overvoltage protection devices are currently used: clamping, which passes through voltages up to a certain level, and foldback, which shunts voltage away from the load. The shunting creates a short circuit which removes power from the protected circuitry. In certain applications this circuitry can reset itself after the dangerous condition has passed.
Fire Alarm Systems
Fire Alarm systems often supervise inputs and outputs with an end-of-line device such as a resistor or capacitor. The system looks for changes in resistance or capacitance values to determine if the circuit has an abnormal condition.
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What type of switch automatically opens a circuit if too much current flows through it?
A. regulator switch
B. kill switch
C. toggle switch
D. circuit breaker
Answer:
|
|
sciq-9244
|
multiple_choice
|
Precipitation maps show the amount of what in different areas?
|
[
"heat",
"geographical variety",
"rainfall",
"population"
] |
C
|
Relavent Documents:
Document 0:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 1:::
The following outline is provided as an overview of and topical guide to the field of Meteorology.
Meteorology The interdisciplinary, scientific study of the Earth's atmosphere with the primary focus being to understand, explain, and forecast weather events. Meteorology, is applied to and employed by a wide variety of diverse fields, including the military, energy production, transport, agriculture, and construction.
Essence of meteorology
Meteorology
Climate – the average and variations of weather in a region over long periods of time.
Meteorology – the interdisciplinary scientific study of the atmosphere that focuses on weather processes and forecasting (in contrast with climatology).
Weather – the set of all the phenomena in a given atmosphere at a given time.
Branches of meteorology
Microscale meteorology – the study of atmospheric phenomena about 1 km or less, smaller than mesoscale, including small and generally fleeting cloud "puffs" and other small cloud features
Mesoscale meteorology – the study of weather systems about 5 kilometers to several hundred kilometers, smaller than synoptic scale systems but larger than microscale and storm-scale cumulus systems, skjjoch as sea breezes, squall lines, and mesoscale convective complexes
Synoptic scale meteorology – is a horizontal length scale of the order of 1000 kilometres (about 620 miles) or more
Methods in meteorology
Surface weather analysis – a special type of weather map that provides a view of weather elements over a geographical area at a specified time based on information from ground-based weather stations
Weather forecasting
Weather forecasting – the application of science and technology to predict the state of the atmosphere for a future time and a given location
Data collection
Pilot Reports
Weather maps
Weather map
Surface weather analysis
Forecasts and reporting of
Atmospheric pressure
Dew point
High-pressure area
Ice
Black ice
Frost
Low-pressure area
Precipitation
Document 2:::
This is a list of meteorology topics. The terms relate to meteorology, the interdisciplinary scientific study of the atmosphere that focuses on weather processes and forecasting. (see also: List of meteorological phenomena)
A
advection
aeroacoustics
aerobiology
aerography (meteorology)
aerology
air parcel (in meteorology)
air quality index (AQI)
airshed (in meteorology)
American Geophysical Union (AGU)
American Meteorological Society (AMS)
anabatic wind
anemometer
annular hurricane
anticyclone (in meteorology)
apparent wind
Atlantic Oceanographic and Meteorological Laboratory (AOML)
Atlantic hurricane season
atmometer
atmosphere
Atmospheric Model Intercomparison Project (AMIP)
Atmospheric Radiation Measurement (ARM)
(atmospheric boundary layer [ABL]) planetary boundary layer (PBL)
atmospheric chemistry
atmospheric circulation
atmospheric convection
atmospheric dispersion modeling
atmospheric electricity
atmospheric icing
atmospheric physics
atmospheric pressure
atmospheric sciences
atmospheric stratification
atmospheric thermodynamics
atmospheric window (see under Threats)
B
ball lightning
balloon (aircraft)
baroclinity
barotropity
barometer ("to measure atmospheric pressure")
berg wind
biometeorology
blizzard
bomb (meteorology)
buoyancy
Bureau of Meteorology (in Australia)
C
Canada Weather Extremes
Canadian Hurricane Centre (CHC)
Cape Verde-type hurricane
capping inversion (in meteorology) (see "severe thunderstorms" in paragraph 5)
carbon cycle
carbon fixation
carbon flux
carbon monoxide (see under Atmospheric presence)
ceiling balloon ("to determine the height of the base of clouds above ground level")
ceilometer ("to determine the height of a cloud base")
celestial coordinate system
celestial equator
celestial horizon (rational horizon)
celestial navigation (astronavigation)
celestial pole
Celsius
Center for Analysis and Prediction of Storms (CAPS) (in Oklahoma in the US)
Center for the Study o
Document 3:::
Crop coefficients are properties of plants used in predicting evapotranspiration (ET). The most basic crop coefficient, Kc, is simply the ratio of ET observed for the crop studied over that observed for the well calibrated reference crop under the same conditions.
Potential evapotranspiration (PET), is the evaporation and transpiration that potentially could occur if a field of the crop had an ideal unlimited water supply. RET is the reference ET often denoted as ET0.
Even in agricultural crops, where ideal conditions are approximated as much as is practical, plants are not always growing (and therefore transpiring) at their theoretical potential. Plants have growth stages and states of health induced by a variety of environmental conditions.
RET usually represents the PET of the reference crop's most active growth. Kc then becomes a function or series of values specific to the crop of interest through its growing season. These can be quite elaborate in the case of certain maize varieties, but tend to use a trapezoidal or leaf area index (LAI) curve for common crop or vegetation canopies.
Stress coefficients, Ks, account for diminished ET due to specific stress factors. These are often assumed to combine by multiplication.
Water stress is the most ubiquitous stress factor, often denoted as Kw. Stress coefficients tend to be functions ranging between 0 and 1. The simplest are linear, but thresholds are appropriate for some toxicity responses. Crop coefficients can exceed 1 when the crop evapotranspiration exceeds that of RET.
Document 4:::
Double mass analysis is a simple graphical method to evaluate the consistency of hydrological data. The DM approach plots the cumulative data of one variable against the cumulative data of a second variable. A break in the slope of a linear function fit to the data is thought to represent a change in the relation between the variables. This approach provides a robust method to determine a change in the behavior of precipitation and recharge in a simple graphical method. It is a commonly used data analysis approach for investigating the behaviour of records made of hydrological or meteorological data at a number of locations. It is used to determine whether there is a need for corrections to the data - to account for changes in data collection procedures or other local conditions. Such changes may result from a variety of things including changes in instrumentation, changes in observation procedures, or changes in gauge location or surrounding conditions. Double mass analysis for checking consistency of a hydrological or meteorological record is considered to be an essential tool before taking it for analysis purpose. This method is based on the hypothesis that each item of the recorded data of a population is consistent.
An example of a double mass analysis is a "double mass plot", or "double mass curve". For this, points and/or a joining line are plotted where the x- and y- coordinates are determined by the running totals of the values observed at two stations. If both stations are affected to the same extent by the same trends then a double mass curve should follow a straight line. A break in the slope of the curve would indicate that conditions have changed at one location but not at another. Breaks in the double-mass curve of such variables are caused by changes in the relation between the variables. These changes may be due to changes in the method of data collection or to physical changes that affect the relation. This technique is based on the principle that
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
Precipitation maps show the amount of what in different areas?
A. heat
B. geographical variety
C. rainfall
D. population
Answer:
|
|
sciq-2591
|
multiple_choice
|
What element is the most common element in the universe?
|
[
"carbon",
"hydrogen",
"nitrogen",
"helium"
] |
B
|
Relavent Documents:
Document 0:::
Conceptual questions or conceptual problems in science, technology, engineering, and mathematics (STEM) education are questions that can be answered based only on the knowledge of relevant concepts, rather than performing extensive calculations. They contrast with most homework and exam problems in science and engineering that typically require plugging in numerical values into previously discussed formulas. Such "plug-and-chug" numerical problems can often be solved correctly by just matching the pattern of the problem to a previously discussed problem and changing the numerical inputs, which requires significant amounts of time to perform the calculations but does not test or deepen the understanding of how the concepts and formulas should work together. Conceptual questions, therefore, provide a good complement to conventional numerical problems because they need minimal or no calculations and instead encourage the students to engage more deeply with the underlying concepts and how they relate to formulas.
Conceptual problems are often formulated as multiple-choice questions, making them easy to use during in-class discussions, particularly when utilizing active learning, peer instruction, and audience response. An example of a conceptual question in undergraduate thermodynamics is provided below:
During adiabatic expansion of an ideal gas, its temperatureincreases
decreases
stays the same
Impossible to tell/need more information
The use of conceptual questions in physics was popularized by Eric Mazur, particularly in the form of multiple-choice tests that he called ConcepTests. In recent years, multiple websites that maintain lists of conceptual questions have been created by instructors for various disciplines. Some books on physics provide many examples of conceptual questions as well.
Multiple conceptual questions can be assembled into a concept inventory to test the working knowledge of students at the beginning of a course or to track the improvement in
Document 1:::
The abundance of the chemical elements is a measure of the occurrence of the chemical elements relative to all other elements in a given environment. Abundance is measured in one of three ways: by mass fraction (in commercial contexts often called weight fraction), by mole fraction (fraction of atoms by numerical count, or sometimes fraction of molecules in gases), or by volume fraction. Volume fraction is a common abundance measure in mixed gases such as planetary atmospheres, and is similar in value to molecular mole fraction for gas mixtures at relatively low densities and pressures, and ideal gas mixtures. Most abundance values in this article are given as mass fractions.
For example, the abundance of oxygen in pure water can be measured in two ways: the mass fraction is about 89%, because that is the fraction of water's mass which is oxygen. However, the mole fraction is about 33% because only 1 atom of 3 in water, H2O, is oxygen. As another example, looking at the mass fraction abundance of hydrogen and helium in both the Universe as a whole and in the atmospheres of gas-giant planets such as Jupiter, it is 74% for hydrogen and 23–25% for helium; while the (atomic) mole fraction for hydrogen is 92%, and for helium is 8%, in these environments. Changing the given environment to Jupiter's outer atmosphere, where hydrogen is diatomic while helium is not, changes the molecular mole fraction (fraction of total gas molecules), as well as the fraction of atmosphere by volume, of hydrogen to about 86%, and of helium to 13%.
The abundance of chemical elements in the universe is dominated by the large amounts of hydrogen and helium which were produced during the Big Bang. Remaining elements, making up only about 2% of the universe, were largely produced by supernovae and certain red giant stars. Lithium, beryllium, and boron, despite their low atomic number, are rare because, although they are produced by nuclear fusion, they are destroyed by other reactions in the st
Document 2:::
This is an index of lists of molecules (i.e. by year, number of atoms, etc.). Millions of molecules have existed in the universe since before the formation of Earth. Three of them, carbon dioxide, water and oxygen were necessary for the growth of life. Although humanity had always been surrounded by these substances, it has not always known what they were composed of.
By century
The following is an index of list of molecules organized by time of discovery of their molecular formula or their specific molecule in case of isomers:
List of compounds
By number of carbon atoms in the molecule
List of compounds with carbon number 1
List of compounds with carbon number 2
List of compounds with carbon number 3
List of compounds with carbon number 4
List of compounds with carbon number 5
List of compounds with carbon number 6
List of compounds with carbon number 7
List of compounds with carbon number 8
List of compounds with carbon number 9
List of compounds with carbon number 10
List of compounds with carbon number 11
List of compounds with carbon number 12
List of compounds with carbon number 13
List of compounds with carbon number 14
List of compounds with carbon number 15
List of compounds with carbon number 16
List of compounds with carbon number 17
List of compounds with carbon number 18
List of compounds with carbon number 19
List of compounds with carbon number 20
List of compounds with carbon number 21
List of compounds with carbon number 22
List of compounds with carbon number 23
List of compounds with carbon number 24
List of compounds with carbon numbers 25-29
List of compounds with carbon numbers 30-39
List of compounds with carbon numbers 40-49
List of compounds with carbon numbers 50+
Other lists
List of interstellar and circumstellar molecules
List of gases
List of molecules with unusual names
See also
Molecule
Empirical formula
Chemical formula
Chemical structure
Chemical compound
Chemical bond
Coordination complex
L
Document 3:::
The interplanetary medium (IPM) or interplanetary space consists of the mass and energy which fills the Solar System, and through which all the larger Solar System bodies, such as planets, dwarf planets, asteroids, and comets, move. The IPM stops at the heliopause, outside of which the interstellar medium begins. Before 1950, interplanetary space was widely considered to either be an empty vacuum, or consisting of "aether".
Composition and physical characteristics
The interplanetary medium includes interplanetary dust, cosmic rays, and hot plasma from the solar wind. The density of the interplanetary medium is very low, decreasing in inverse proportion to the square of the distance from the Sun. It is variable, and may be affected by magnetic fields and events such as coronal mass ejections. Typical particle densities in the interplanetary medium are about 5-40 particles/cm, but exhibit substantial variation. In the vicinity of the Earth, it contains about 5 particles/cm, but values as high as 100 particles/cm have been observed.
The temperature of the interplanetary medium varies through the solar system. Joseph Fourier estimated that interplanetary medium must have temperatures comparable to those observed at Earth's poles, but on faulty grounds: lacking modern estimates of atmospheric heat transport, he saw no other means to explain the relative consistency of earth's climate. A very hot interplanetary medium remained a minor position among geophysicists as late as 1959, when Chapman proposed a temperature on the order of 10000 K, but observation in Low Earth orbit of the exosphere soon contradicted his position. In fact, both Fourier and Chapman's final predictions were correct: because the interplanetary medium is so rarefied, it does not exhibit thermodynamic equilibrium. Instead, different components have different temperatures. The solar wind exhibits temperatures consistent with Chapman's estimate in cislunar space, and dust particles near Earth's
Document 4:::
This is a list of topics that are included in high school physics curricula or textbooks.
Mathematical Background
SI Units
Scalar (physics)
Euclidean vector
Motion graphs and derivatives
Pythagorean theorem
Trigonometry
Motion and forces
Motion
Force
Linear motion
Linear motion
Displacement
Speed
Velocity
Acceleration
Center of mass
Mass
Momentum
Newton's laws of motion
Work (physics)
Free body diagram
Rotational motion
Angular momentum (Introduction)
Angular velocity
Centrifugal force
Centripetal force
Circular motion
Tangential velocity
Torque
Conservation of energy and momentum
Energy
Conservation of energy
Elastic collision
Inelastic collision
Inertia
Moment of inertia
Momentum
Kinetic energy
Potential energy
Rotational energy
Electricity and magnetism
Ampère's circuital law
Capacitor
Coulomb's law
Diode
Direct current
Electric charge
Electric current
Alternating current
Electric field
Electric potential energy
Electron
Faraday's law of induction
Ion
Inductor
Joule heating
Lenz's law
Magnetic field
Ohm's law
Resistor
Transistor
Transformer
Voltage
Heat
Entropy
First law of thermodynamics
Heat
Heat transfer
Second law of thermodynamics
Temperature
Thermal energy
Thermodynamic cycle
Volume (thermodynamics)
Work (thermodynamics)
Waves
Wave
Longitudinal wave
Transverse waves
Transverse wave
Standing Waves
Wavelength
Frequency
Light
Light ray
Speed of light
Sound
Speed of sound
Radio waves
Harmonic oscillator
Hooke's law
Reflection
Refraction
Snell's law
Refractive index
Total internal reflection
Diffraction
Interference (wave propagation)
Polarization (waves)
Vibrating string
Doppler effect
Gravity
Gravitational potential
Newton's law of universal gravitation
Newtonian constant of gravitation
See also
Outline of physics
Physics education
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What element is the most common element in the universe?
A. carbon
B. hydrogen
C. nitrogen
D. helium
Answer:
|
|
sciq-1423
|
multiple_choice
|
What do stored fats provide our body with for later use?
|
[
"hydrogen",
"metals",
"water",
"energy"
] |
D
|
Relavent Documents:
Document 0:::
An unsaturated fat is a fat or fatty acid in which there is at least one double bond within the fatty acid chain. A fatty acid chain is monounsaturated if it contains one double bond, and polyunsaturated if it contains more than one double bond.
A saturated fat has no carbon to carbon double bonds, so the maximum possible number of hydrogens bonded to the carbons, and is "saturated" with hydrogen atoms. To form carbon to carbon double bonds, hydrogen atoms are removed from the carbon chain. In cellular metabolism, unsaturated fat molecules contain less energy (i.e., fewer calories) than an equivalent amount of saturated fat. The greater the degree of unsaturation in a fatty acid (i.e., the more double bonds in the fatty acid) the more vulnerable it is to lipid peroxidation (rancidity). Antioxidants can protect unsaturated fat from lipid peroxidation.
Composition of common fats
In chemical analysis, fats are broken down to their constituent fatty acids, which can be analyzed in various ways. In one approach, fats undergo transesterification to give fatty acid methyl esters (FAMEs), which are amenable to separation and quantitation using by gas chromatography. Classically, unsaturated isomers were separated and identified by argentation thin-layer chromatography.
The saturated fatty acid components are almost exclusively stearic (C18) and palmitic acids (C16). Monounsaturated fats are almost exclusively oleic acid. Linolenic acid comprises most of the triunsaturated fatty acid component.
Chemistry and nutrition
Although polyunsaturated fats are protective against cardiac arrhythmias, a study of post-menopausal women with a relatively low fat intake showed that polyunsaturated fat is positively associated with progression of coronary atherosclerosis, whereas monounsaturated fat is not. This probably is an indication of the greater vulnerability of polyunsaturated fats to lipid peroxidation, against which vitamin E has been shown to be protective.
Examples
Document 1:::
Animal nutrition focuses on the dietary nutrients needs of animals, primarily those in agriculture and food production, but also in zoos, aquariums, and wildlife management.
Constituents of diet
Macronutrients (excluding fiber and water) provide structural material (amino acids from which proteins are built, and lipids from which cell membranes and some signaling molecules are built) and energy. Some of the structural material can be used to generate energy internally, though the net energy depends on such factors as absorption and digestive effort, which vary substantially from instance to instance. Vitamins, minerals, fiber, and water do not provide energy, but are required for other reasons. A third class dietary material, fiber (i.e., non-digestible material such as cellulose), seems also to be required, for both mechanical and biochemical reasons, though the exact reasons remain unclear.
Molecules of carbohydrates and fats consist of carbon, hydrogen, and oxygen atoms. Carbohydrates range from simple monosaccharides (glucose, fructose, galactose) to complex polysaccharides (starch). Fats are triglycerides, made of assorted fatty acid monomers bound to glycerol backbone. Some fatty acids, but not all, are essential in the diet: they cannot be synthesized in the body. Protein molecules contain nitrogen atoms in addition to carbon, oxygen, and hydrogen. The fundamental components of protein are nitrogen-containing amino acids. Essential amino acids cannot be made by the animal. Some of the amino acids are convertible (with the expenditure of energy) to glucose and can be used for energy production just as ordinary glucose. By breaking down existing protein, some glucose can be produced internally; the remaining amino acids are discarded, primarily as urea in urine. This occurs normally only during prolonged starvation.
Other dietary substances found in plant foods (phytochemicals, polyphenols) are not identified as essential nutrients but appear to impact healt
Document 2:::
Body composition may be analyzed in various ways. This can be done in terms of the chemical elements present, or by molecular structure e.g., water, protein, fats (or lipids), hydroxylapatite (in bones), carbohydrates (such as glycogen and glucose) and DNA. In terms of tissue type, the body may be analyzed into water, fat, connective tissue, muscle, bone, etc. In terms of cell type, the body contains hundreds of different types of cells, but notably, the largest number of cells contained in a human body (though not the largest mass of cells) are not human cells, but bacteria residing in the normal human gastrointestinal tract.
Elements
About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium. All 11 are necessary for life. The remaining elements are trace elements, of which more than a dozen are thought on the basis of good evidence to be necessary for life. All of the mass of the trace elements put together (less than 10 grams for a human body) do not add up to the body mass of magnesium, the least common of the 11 non-trace elements.
Other elements
Not all elements which are found in the human body in trace quantities play a role in life. Some of these elements are thought to be simple common contaminants without function (examples: caesium, titanium), while many others are thought to be active toxins, depending on amount (cadmium, mercury, lead, radioactives). In humans, arsenic is toxic, and its levels in foods and dietary supplements are closely monitored to reduce or eliminate its intake.
Some elements (silicon, boron, nickel, vanadium) are probably needed by mammals also, but in far smaller doses. Bromine is used abundantly by some (though not all) lower organisms, and opportunistically in eosinophils in humans. One study has indicated bromine to be necessary to collagen IV synthe
Document 3:::
Relatively speaking, the brain consumes an immense amount of energy in comparison to the rest of the body. The mechanisms involved in the transfer of energy from foods to neurons are likely to be fundamental to the control of brain function. Human bodily processes, including the brain, all require both macronutrients, as well as micronutrients.
Insufficient intake of selected vitamins, or certain metabolic disorders, may affect cognitive processes by disrupting the nutrient-dependent processes within the body that are associated with the management of energy in neurons, which can subsequently affect synaptic plasticity, or the ability to encode new memories.
Macronutrients
The human brain requires nutrients obtained from the diet to develop and sustain its physical structure and cognitive functions. Additionally, the brain requires caloric energy predominately derived from the primary macronutrients to operate. The three primary macronutrients include carbohydrates, proteins, and fats. Each macronutrient can impact cognition through multiple mechanisms, including glucose and insulin metabolism, neurotransmitter actions, oxidative stress and inflammation, and the gut-brain axis. Inadequate macronutrient consumption or proportion could impair optimal cognitive functioning and have long-term health implications.
Carbohydrates
Through digestion, dietary carbohydrates are broken down and converted into glucose, which is the sole energy source for the brain. Optimal brain function relies on adequate carbohydrate consumption, as carbohydrates provide the quickest source of glucose for the brain. Glucose deficiencies such as hypoglycaemia reduce available energy for the brain and impair all cognitive processes and performance. Additionally, situations with high cognitive demand, such as learning a new task, increase brain glucose utilization, depleting blood glucose stores and initiating the need for supplementation.
Complex carbohydrates, especially those with high d
Document 4:::
Human nutrition deals with the provision of essential nutrients in food that are necessary to support human life and good health. Poor nutrition is a chronic problem often linked to poverty, food security, or a poor understanding of nutritional requirements. Malnutrition and its consequences are large contributors to deaths, physical deformities, and disabilities worldwide. Good nutrition is necessary for children to grow physically and mentally, and for normal human biological development.
Overview
The human body contains chemical compounds such as water, carbohydrates, amino acids (found in proteins), fatty acids (found in lipids), and nucleic acids (DNA and RNA). These compounds are composed of elements such as carbon, hydrogen, oxygen, nitrogen, and phosphorus. Any study done to determine nutritional status must take into account the state of the body before and after experiments, as well as the chemical composition of the whole diet and of all the materials excreted and eliminated from the body (including urine and feces).
Nutrients
The seven major classes of nutrients are carbohydrates, fats, fiber, minerals, proteins, vitamins, and water. Nutrients can be grouped as either macronutrients or micronutrients (needed in small quantities). Carbohydrates, fats, and proteins are macronutrients, and provide energy. Water and fiber are macronutrients but do not provide energy. The micronutrients are minerals and vitamins.
The macronutrients (excluding fiber and water) provide structural material (amino acids from which proteins are built, and lipids from which cell membranes and some signaling molecules are built), and energy. Some of the structural material can also be used to generate energy internally, and in either case it is measured in Joules or kilocalories (often called "Calories" and written with a capital 'C' to distinguish them from little 'c' calories). Carbohydrates and proteins provide 17 kJ approximately (4 kcal) of energy per gram, while fats prov
The following are multiple choice questions (with answers) about knowledge and skills in advanced master-level STEM courses.
What do stored fats provide our body with for later use?
A. hydrogen
B. metals
C. water
D. energy
Answer:
|
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