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Microevolution Mutation Microevolution > Four processes > Mutation Novel genes are produced by several methods, commonly through the duplication and mutation of an ancestral gene, or by recombining parts of different genes to form new combinations with new functions.Here, domains act as modules, each with a particular and independent function, that can be mixed together to produce genes encoding new proteins with novel properties. For example, the human eye uses four genes to make structures that sense light: three for color vision and one for night vision; all four arose from a single ancestral gene. Another advantage of duplicating a gene (or even an entire genome) is that this increases redundancy; this allows one gene in the pair to acquire a new function while the other copy performs the original function. Other types of mutation occasionally create new genes from previously noncoding DNA.
Flux balance analysis Dynamic FBA Flux_balance_analysis > Extensions > Dynamic FBA Dynamic FBA attempts to add the ability for models to change over time, thus in some ways avoiding the strict steady state condition of pure FBA. Typically the technique involves running an FBA simulation, changing the model based on the outputs of that simulation, and rerunning the simulation. By repeating this process an element of feedback is achieved over time.
Bypassing capacitor Summary Bypass_capacitor In electronics, a decoupling capacitor is a capacitor used to decouple (i.e. prevent electrical energy from transferring to) one part of a circuit from another. Noise caused by other circuit elements is shunted through the capacitor, reducing its effect on the rest of the circuit. For higher frequencies, an alternative name is bypass capacitor as it is used to bypass the power supply or other high-impedance component of a circuit.
Mast cells MRGPRX2 mast cell receptor Mast_cell > Physiology > MRGPRX2 mast cell receptor Human mast-cell-specific G-protein-coupled receptor MRGPRX2 plays a key role in the recognition of pathogen associated molecular patterns (PAMPs) and initiating an antibacterial response. MRGPRX2 is able to bind to competence stimulating peptide (CSP) 1 - a quorum sensing molecule (QSM) produced by Gram-positive bacteria. This leads to signal transduction to a G protein and activation of the mast cell. Mast cell activation induces the release of antibacterial mediators including ROS, TNF-α and PRGD2 which institute the recruitment of other immune cells to inhibit bacterial growth and biofilm formation.
Relationships and health Models Relationships_and_health > Models The difference between the two of them is that a threshold effect is a necessary amount of social support required to have a positive effect on health, on the opposite, a gradient effect can be described as a linear effect of the amount of social support on health, meaning that an increase of x amount of social support will result in an increase of y level of health. The second model proposed by Cohen and Wills (1985) is the stress-buffering model. This model explains the effect of social networks on health when an individual is facing a stressful event.
PPN formalism Accuracy from experimental tests PPN_formalism > Accuracy from experimental tests Bounds on the PPN parameters from Will (2006) and Will (2014) † Will, C. M. (10 July 1992). "Is momentum conserved? A test in the binary system PSR 1913 + 16".
Quantum economics Summary Quantum_economics Quantum economics is an emerging research field which applies mathematical methods and ideas from quantum physics to the field of economics. It is motivated by the belief that economic processes such as financial transactions have much in common with quantum processes, and can be appropriately modeled using the quantum formalism. It draws on techniques from the related areas of quantum finance and quantum cognition, and is a sub-field of quantum social science.
Icosahedral group Summary Icosahedral_group In mathematics, and especially in geometry, an object has icosahedral symmetry if it has the same symmetries as a regular icosahedron. Examples of other polyhedra with icosahedral symmetry include the regular dodecahedron (the dual of the icosahedron) and the rhombic triacontahedron. Every polyhedron with icosahedral symmetry has 60 rotational (or orientation-preserving) symmetries and 60 orientation-reversing symmetries (that combine a rotation and a reflection), for a total symmetry order of 120. The full symmetry group is the Coxeter group of type H3. It may be represented by Coxeter notation and Coxeter diagram . The set of rotational symmetries forms a subgroup that is isomorphic to the alternating group A5 on 5 letters.
Diethylene glycol Prognosis Diethylene_glycol > Toxicology > Prognosis The prognosis depends on prompt diagnosis and treatment due to the high mortality rate DEG intoxication produces. Patients who survive but develop kidney failure remain dialysis-dependent. All patients are likely to suffer significant morbidity.
Mathematical manipulatives Linking cubes Mathematical_manipulatives > In teaching and learning > Linking cubes The difference is that a student can also physically decompose a pattern by the unit. For example, if a student made a pattern train that followed this sequence: Red, blue, blue, blue, red, blue, blue, blue, red, blue, blue, blue, red, blue, blue, ... the child could then be asked to identify the unit that is repeating (red, blue, blue, blue) and take apart the pattern by each unit. Also, one can learn addition, subtraction, multiplication and division, guesstimation, measuring, and graphing, perimeter, area, and volume.
Fisher kernel Information retrieval Fisher_kernel > Applications > Information retrieval The Fisher kernel is the kernel for a generative probabilistic model. As such, it constitutes a bridge between generative and probabilistic models of documents. Fisher kernels exist for numerous models, notably tf–idf, Naive Bayes and probabilistic latent semantic analysis.
Eye movement in language reading Early tracking technology Eye_movement_in_language_reading > History > Early tracking technology Eye tracking device is a tool created to help measure eye and head movements. The first devices for tracking eye movement took two main forms: those that relied on a mechanical connection between participant and recording instrument, and those in which light or some other form of electromagnetic energy was directed at the participant's eyes and its reflection measured and recorded. In 1883, Lamare was the first to use a mechanical connection, by placing a blunt needle on the participant's upper eyelid. The needle picked up the sound produced by each saccade and transmitted it as a faint clicking to the experimenter's ear through an amplifying membrane and a rubber tube.
Method body Summary Method_body In object-oriented programming, a class implementation file is often used to contain the implementation code for the method(s) of a class. Programming languages like C and C++ make use of these implementation files so as to separate the interface and implementation of these methods.
Fourier shift theorem Fourier transform for periodic functions Fourier_Transform > Background > Fourier transform for periodic functions It is possible to extend the definition to include periodic functions by viewing them as tempered distributions. This makes it possible to see a connection between the Fourier series and the Fourier transform for periodic functions which have a convergent Fourier series. If f ( x ) {\displaystyle f(x)} is a periodic function, with period P {\displaystyle P} , that has a convergent Fourier series, then: f ^ ( ξ ) = ∑ n = − ∞ ∞ c n ⋅ δ ( ξ − n P ) , {\displaystyle {\hat {f}}(\xi )=\sum _{n=-\infty }^{\infty }c_{n}\cdot \delta \left(\xi -{\tfrac {n}{P}}\right),} where c n {\displaystyle c_{n}} are the Fourier series coefficients of f {\displaystyle f} , and δ {\displaystyle \delta } is the Dirac delta function. In other words the Fourier transform is a Dirac comb function whose teeth are multiplied by the Fourier series coefficients.
Experimental finance Scientific value Experimental_finance > Scientific value In experimental markets the researcher is able to know expectations, and control fundamental values, trading institutions, and market parameters such as available liquidity and the total stock of the asset. This gives the researcher the ability to know the price and other predictions of alternative theories. This creates the opportunity to do powerful tests on the robustness of theories which were not possible from field data, since there is little knowledge on the parameters and expectations from field data.
Machine vision glossary E Glossary_of_machine_vision > E Edge detection. ED marks the points in a digital image at which the luminous intensity changes sharply. It also marks the points of luminous intensity changes of an object or spatial-taxon silhouette. Electromagnetic interference. Radio Frequency Interference (RFI) is electromagnetic radiation which is emitted by electrical circuits carrying rapidly changing signals, as a by-product of their normal operation, and which causes unwanted signals (interference or noise) to be induced in other circuits.
Psychology of self Parts of the self Psychology_of_self > Parts of the self The self is an automatic part of every human being, in which enables people to relate to others. The self is made up of three main parts that, incorporated, allow for the self to maintain its function. The parts of the self include: Self-knowledge, interpersonal self, and the agent self.
Post-traumatic stress disorder Antidepressants Post-traumatic_stress_disorder > Management > Medication > Antidepressants Selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) may have some benefit for PTSD symptoms. Tricyclic antidepressants are equally effective, but are less well tolerated. Evidence provides support for a small or modest improvement with sertraline, fluoxetine, paroxetine, and venlafaxine. Thus, these four medications are considered to be first-line medications for PTSD.
Hill system Overview Chemical_Formula > Overview For example, one systematic name for glucose is (2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhexanal. This name, interpreted by the rules behind it, fully specifies glucose's structural formula, but the name is not a chemical formula as usually understood, and uses terms and words not used in chemical formulae. Such names, unlike basic formulae, may be able to represent full structural formulae without graphs.
Three-phase traffic theory The "synchronized flow" phase [S] Three_phase_traffic_theory > Definitions [J] and [S] of the phases J and S in congested traffic > The "synchronized flow" phase [S] (ii) There is a tendency towards synchronization of vehicle speeds across different lanes on a multilane road in this flow. In addition, there is a tendency towards synchronization of vehicle speeds in each of the road lanes (bunching of vehicles) in synchronized flow. This is due to a relatively low probability of passing. The term "synchronized" reflects this speed synchronization effect.
Single instruction, multiple threads Description Single_instruction,_multiple_threads > Description As access time of all the widespread RAM types (e.g. DDR SDRAM, GDDR SDRAM, XDR DRAM, etc.) is still relatively high, engineers came up with the idea to hide the latency that inevitably comes with each memory access. Strictly, the latency-hiding is a feature of the zero-overhead scheduling implemented by modern GPUs. This might or might not be considered to be a property of 'SIMT' itself. SIMT is intended to limit instruction fetching overhead, i.e. the latency that comes with memory access, and is used in modern GPUs (such as those of Nvidia and AMD) in combination with 'latency hiding' to enable high-performance execution despite considerable latency in memory-access operations.
Greenhouse Gases Effect at top-of-atmosphere (TOA) Green_house_gases > Role in heat transport and radiative forcing > Effect at top-of-atmosphere (TOA) At the top of the atmosphere (TOA), absorbing and emission of thermal radiation by greenhouse gases leads to inhibition of radiative cooling to space, which means the amount of thermal radiation reaching space is reduced, relative to what is emitted by the surface. The change in TOA energy balance leads to the surface accumulating thermal energy and warming until TOA energy balance is achieved.
Travelling salesman problem V-opt heuristic Travelling_salesman_problem > Computing a solution > Heuristic and approximation algorithms > V-opt heuristic The variable-opt method is related to, and a generalization of the k-opt method. Whereas the k-opt methods remove a fixed number (k) of edges from the original tour, the variable-opt methods do not fix the size of the edge set to remove. Instead, they grow the set as the search process continues.
Pythagorean equation Rearrangement proofs Pythagoras's_theorem > Proofs using constructed squares > Rearrangement proofs In this way they also form two boxes, this time in consecutive corners, with areas a 2 {\displaystyle a^{2}} and b 2 {\displaystyle b^{2}} which will again lead to a second square of with the area 2 a b + a 2 + b 2 {\displaystyle 2ab+a^{2}+b^{2}} . English mathematician Sir Thomas Heath gives this proof in his commentary on Proposition I.47 in Euclid's Elements, and mentions the proposals of German mathematicians Carl Anton Bretschneider and Hermann Hankel that Pythagoras may have known this proof. Heath himself favors a different proposal for a Pythagorean proof, but acknowledges from the outset of his discussion "that the Greek literature which we possess belonging to the first five centuries after Pythagoras contains no statement specifying this or any other particular great geometric discovery to him." Recent scholarship has cast increasing doubt on any sort of role for Pythagoras as a creator of mathematics, although debate about this continues.
Viral strategies for immune response evasion Nucleic acid shielding Viral_strategies_for_immune_response_evasion > Viral evasion strategies > Nucleic acid shielding Other viruses utilize host cell proteins to shield viral DNA until it has reached the nucleus. Upon entry into the host cell cytoplasm, the HIV-1 capsid is recognized and bound by cyclophilin A (CypA); this affinity interaction stabilizes the capsid and prevents exposure of the HIV-1 cDNA to pattern recognition receptors in the cytoplasm. This shielding allows the HIV-1 cDNA to translocate to the nucleus where it may begin replication. == References ==
Organic electronics Organic field-effect transistor Organic_electronics > Organic field-effect transistor An Organic field-effect transistor is a field-effect transistor utilizing organic molecules or polymers as the active semiconducting layer. A field-effect transistor (FET) is any semiconductor material that utilizes electric field to control the shape of a channel of one type of charge carrier, thereby changing its conductivity. Two major classes of FET are n-type and p-type semiconductor, classified according to the charge type carried. In the case of organic FETs (OFETs), p-type OFET compounds are generally more stable than n-type due to the susceptibility of the latter to oxidative damage.
Computer sciences Programming paradigms Computer_science > Programming paradigms A feature of objects is that an object's procedures can access and often modify the data fields of the object with which they are associated. Thus object-oriented computer programs are made out of objects that interact with one another. Service-oriented programming, a programming paradigm that uses "services" as the unit of computer work, to design and implement integrated business applications and mission critical software programsMany languages offer support for multiple paradigms, making the distinction more a matter of style than of technical capabilities.
Micrometer (device) Operating principles Micrometer_screw_gauge > Operating principles The basic operating principles of a micrometer are as follows: The amount of rotation of an accurately made screw can be directly and precisely correlated to a certain amount of axial movement (and vice versa), through the constant known as the screw's lead (/ˈliːd/). A screw's lead is the distance it moves forward axially with one complete turn (360°). (In most threads , lead and pitch refer to essentially the same concept.)
Twelvefold way Surjective functions from N to X, up to a permutation of N Twelvefold_way > Formulas > Details of the different cases > Surjective functions from N to X, up to a permutation of N × ( 2 − 1 ) ! = 2 {\displaystyle \left\vert \{\{a,a,b\},\{a,b,b\}\}\right\vert ={\binom {3-1}{3-2}}={\binom {2}{1}}={\frac {2! }{1!\times (2-1)! }}=2}
Bridge barrier Stiffness Crash_barrier > Types and performance > Stiffness Impact forces are resisted by a combination of the rigidity and mass of the barrier. Deflection is usually negligible.
Rolle's Theorem First example Rolle's_Theorem > Examples > First example For a radius r > 0, consider the function Its graph is the upper semicircle centered at the origin. This function is continuous on the closed interval and differentiable in the open interval (−r, r), but not differentiable at the endpoints −r and r. Since f (−r) = f (r), Rolle's theorem applies, and indeed, there is a point where the derivative of f is zero. The theorem applies even when the function cannot be differentiated at the endpoints because it only requires the function to be differentiable in the open interval.
Deep homology Life cycle of cancer Deep_homology > Future endeavors in science; deep homology of cancer stem cells > Life cycle of cancer This cancer germ-line undergoes a process of development that is similar to the Entamoeba germline. A significant trace of deep homology can be found in mammalian germ-line stem cells. Based on a previous hypothesis, the germ-line is the common ancestor in somatic stem cell lineages. Daughter GSCs are the only stem cells that have the capability of passing genetic information throughout generations.
Page fault Performance impact Invalid_page_fault > Performance impact Page faults degrade system performance and can cause thrashing. Major page faults on conventional computers using hard disk drives can have a significant impact on their performance, as an average hard disk drive has an average rotational latency of 3 ms, a seek time of 5 ms, and a transfer time of 0.05 ms/page. Therefore, the total time for paging is near 8 ms (= 8,000 μs). If the memory access time is 0.2 μs, then the page fault would make the operation about 40,000 times slower.
Numbered list Alphabetical Collation_algorithm > Ordering > Alphabetical When some of the strings contain numerals (or other non-letter characters), various approaches are possible. Sometimes such characters are treated as if they came before or after all the letters of the alphabet. Another method is for numbers to be sorted alphabetically as they would be spelled: for example 1776 would be sorted as if spelled out "seventeen seventy-six", and 24 heures du Mans as if spelled "vingt-quatre..." (French for "twenty-four").
Bijection, injection and surjection Summary Bijection,_injection_and_surjection In mathematics, injections, surjections, and bijections are classes of functions distinguished by the manner in which arguments (input expressions from the domain) and images (output expressions from the codomain) are related or mapped to each other. A function maps elements from its domain to elements in its codomain. Given a function f: X → Y {\displaystyle f\colon X\to Y}: The function is injective, or one-to-one, if each element of the codomain is mapped to by at most one element of the domain, or equivalently, if distinct elements of the domain map to distinct elements in the codomain. An injective function is also called an injection.
Quantitative comparative linguistics Types of trees and networks Quantitative_comparative_linguistics > Types of trees and networks An output of a quantitative historical linguistic analysis is normally a tree or a network diagram. This allows summary visualisation of the output data but is not the complete result. A tree is a connected acyclic graph, consisting of a set of vertices (also known as "nodes") and a set of edges ("branches") each of which connects a pair of vertices. An internal node represents a linguistic ancestor in a phylogenic tree or network.
Protein hydroxylation Summary Protein_hydroxylation In chemistry, hydroxylation can refer to: (i) most commonly, hydroxylation describes a chemical process that introduces a hydroxyl group (−OH) into an organic compound. (ii) the degree of hydroxylation refers to the number of OH groups in a molecule. The pattern of hydroxylation refers to the location of hydroxy groups on a molecule or material.
Slide Rule Summary Slide_rules At its simplest, each number to be multiplied is represented by a length on a pair of parallel rulers that can slide past each other. As the rulers each have a logarithmic scale, it is possible to align them to read the sum of the numbers' logarithms, which according to the law of the logarithm of a product equals the product of the two numbers. English mathematician and clergyman Reverend William Oughtred and others developed the slide rule in the 17th century based on the emerging work on logarithms by John Napier.
Parallel robot Summary Parallel_manipulator Also known as parallel robots, or generalized Stewart platforms (in the Stewart platform, the actuators are paired together on both the basis and the platform), these systems are articulated robots that use similar mechanisms for the movement of either the robot on its base, or one or more manipulator arms. Their 'parallel' distinction, as opposed to a serial manipulator, is that the end effector (or 'hand') of this linkage (or 'arm') is directly connected to its base by a number of (usually three or six) separate and independent linkages working simultaneously. No geometrical parallelism is implied.
Turing equivalence (recursion theory) Summary Recursively_enumerable_Turing_degree In computer science and mathematical logic the Turing degree (named after Alan Turing) or degree of unsolvability of a set of natural numbers measures the level of algorithmic unsolvability of the set.
Spindle checkpoint Cell division: duplication of material and distribution to daughter cells Spindle_assembly_checkpoint > Background on sister chromatid duplication, cohesion, and segregation > Cell division: duplication of material and distribution to daughter cells In this way, when the two daughter cells separate at the end of the division process, each one will contain a complete set of chromatids. The mechanism responsible for the correct distribution of sister chromatids during cell division is named chromosome segregation. To ensure that chromosome segregation takes place correctly, cells have developed a precise and complex mechanism. In the first place, cells must coordinate centrosome duplication with DNA replication, and a failure in this coordination will generate monopolar or multipolar mitotic spindles, which generally will produce abnormal chromosome segregation, because in this case, chromosome distribution will not take place in a balanced way.
Metabolic route Regulation Metabolic_pathway > Regulation The flux of the entire pathway is regulated by the rate-determining steps. : 577–578 These are the slowest steps in a network of reactions. The rate-limiting step occurs near the beginning of the pathway and is regulated by feedback inhibition, which ultimately controls the overall rate of the pathway. The metabolic pathway in the cell is regulated by covalent or non-covalent modifications.
Neurogenetics Cross-species gene conservation Neurogenetics > Behavioral neurogenetics > Cross-species gene conservation While it is true that variation between species can appear to be pronounced, at their most basic they share many similar behavior traits which are necessary for survival. Such traits include mating, aggression, foraging, social behavior and sleep patterns. This conservation of behavior across species has led biologists to hypothesize that these traits could possibly have similar, if not the same, genetic causes and pathways. Studies conducted on the genomes of a plethora of organisms have revealed that many organisms have homologous genes, meaning that some genetic material has been conserved between species. If these organisms shared a common evolutionary ancestor, then this might imply that aspects of behavior can be inherited from previous generations, lending support to the genetic causes – as opposed to the environmental causes – of behavior. Variations in personalities and behavioral traits seen amongst individuals of the same species could be explained by differing levels of expression of these genes and their corresponding proteins.
Electrostatic induction Charging an object by induction Electrostatic_induction > Charging an object by induction The electroscope now contains a net charge opposite in polarity to that of the charged object. When the electrical contact to earth is broken, e.g. by lifting the finger, the extra charge that has just flowed into the electroscope cannot escape, and the instrument retains a net charge. The charge is held in the top of the electroscope terminal by the attraction of the inducing charge.
Collection (abstract data type) Lists Collection_(abstract_data_type) > Linear collections > Lists If the principal operations are the addition and removal of data items at just one end, it will be called a stack or LIFO. In both cases, data items are maintained within the collection in the same order (unless they are removed and re-inserted somewhere else) and so these are special cases of the list collection. Other specialized operations on lists include sorting, where, again, the order of data items is of great importance.
ENZYME STRUCTURE AND FUNCTION Involvement in disease Enzyme > Biological function > Involvement in disease Oral administration of enzymes can be used to treat some functional enzyme deficiencies, such as pancreatic insufficiency and lactose intolerance.Another way enzyme malfunctions can cause disease comes from germline mutations in genes coding for DNA repair enzymes. Defects in these enzymes cause cancer because cells are less able to repair mutations in their genomes. This causes a slow accumulation of mutations and results in the development of cancers. An example of such a hereditary cancer syndrome is xeroderma pigmentosum, which causes the development of skin cancers in response to even minimal exposure to ultraviolet light.
Process management (computing) Processor modes Process_management_(computing) > Processor modes If the mode bit is set to kernel mode, the process executing in the processor can access either the kernel or user partition of the memory. However, if user mode is set, the process can reference only the user memory space. We frequently refer to two classes of memory user space and system space (or kernel, supervisor or protected space).
Turing-computable function The "state" Turing_Machines > Additional details required to visualize or implement Turing machines > The "state" 374–375). Hopcroft and Ullman call this composite the "instantaneous description" and follow the Turing convention of putting the "current state" (instruction-label, m-configuration) to the left of the scanned symbol (p. 149), that is, the instantaneous description is the composite of non-blank symbols to the left, state of the machine, the current symbol scanned by the head, and the non-blank symbols to the right.
Social genomics Biological pathways Social_genomics > Biological pathways Thus a bias towards anti-viral readiness would be adaptive. In conditions of social stress however, the up-regulation of pro-inflammatory gene expression prepares the body to better deal with bodily injury and bacterial infection which is more likely under conditions of social stress either through hostile human contact, or increased predatory vulnerability due to separation from the social group. In the modern age however, the chronic elevation of pro-inflammatory gene expression produced by social stress is more likely to result in inflammation-related diseases including various cancers, cardiovascular disease and rheumatoid arthritis.
Data Intensive Computing Introduction Data_Intensive_Computing > Introduction Parallel processing of data-intensive applications typically involves partitioning or subdividing the data into multiple segments which can be processed independently using the same executable application program in parallel on an appropriate computing platform, then reassembling the results to produce the completed output data. The greater the aggregate distribution of the data, the more benefit there is in parallel processing of the data. Data-intensive processing requirements normally scale linearly according to the size of the data and are very amenable to straightforward parallelization. The fundamental challenges for data-intensive computing are managing and processing exponentially growing data volumes, significantly reducing associated data analysis cycles to support practical, timely applications, and developing new algorithms which can scale to search and process massive amounts of data. Researchers coined the term BORPS for "billions of records per second" to measure record processing speed in a way analogous to how the term MIPS applies to describe computers' processing speed.
OS kernel System calls Operating_system_kernel > System calls In computing, a system call is how a process requests a service from an operating system's kernel that it does not normally have permission to run. System calls provide the interface between a process and the operating system. Most operations interacting with the system require permissions not available to a user-level process, e.g., I/O performed with a device present on the system, or any form of communication with other processes requires the use of system calls. A system call is a mechanism that is used by the application program to request a service from the operating system.
Friction drive In automobiles Friction_drive > In automobiles Automobiles using this drive system included the Anglo-Dane, the Arista, the Armadale, the Astra, the Allvelo, the Bukh & Gry, the Cartercar, the Crown 12HP Model Two (1905-1906), the Davis Totem, the G.W.K., the Kelsey, the Lambert, the LuLu, the Metz, the Ner-a Car, the Richardson, and the Turicum. The Turicum's friction drive consisted of a flat steel disk coupled directly to the engine. This primary disk subsequently drove a smaller leather covered wheel oriented normal to its surface. Assuming a constant rotational velocity on the primary wheel, the angular velocity on the disk's surface will increase proportionally to the distance from the center of rotation.
Electron diffraction Kinematical diffraction Electron_diffraction > Basics > Kinematical diffraction The intensity in transmission electron diffraction oscillates as a function of thickness, which can be confusing; there can similarly be intensity changes due to variations in orientation and also structural defects such as dislocations. If a diffraction spots is strong it could be because it has a larger structure factor, or it could be because the combination of thickness and excitation error is "right". Similarly the observed intensity can be small, even though the structure factor is large.
Learning theories Transformative learning theory Learning_theory_(education) > Educational psychology > Transformative learning theory Adults have a tendency to reject any ideas that do not correspond to their particular values, associations and concepts.Our frames of reference are composed of two dimensions: habits of mind and points of view. Habits of mind, such as ethnocentrism, are harder to change than points of view. Habits of mind influence our point of view and the resulting thoughts or feelings associated with them, but points of view may change over time as a result of influences such as reflection, appropriation and feedback. Transformative learning takes place by discussing with others the "reasons presented in support of competing interpretations, by critically examining evidence, arguments, and alternative points of view". When circumstances permit, transformative learners move toward a frame of reference that is more inclusive, discriminating, self-reflective, and integrative of experience.
Elastance Other analogies Elastance > Mechanical analogy > Other analogies Maxwell's analogy is not the only way that analogies can be constructed between mechanical and electrical systems. There are any number of ways to do this. One very common system is the mobility analogy. In this analogy force maps to current instead of voltage. Electrical impedance no longer maps to mechanical impedance, and likewise, electrical elastance no longer maps to mechanical elastance.
Transfusion related acute lung injury Pathophysiology Transfusion_related_acute_lung_injury > Pathophysiology The second hit in TRALI may be conveyed by anti-leukocyte antibodies or other factors present in the transfusion product. In approximately 80% of cases, anti-HLA class I or II or anti-HNA antibodies are implicated as involved in triggering TRALI, although that figure may be even higher depending on the detection methods used. In the remaining 20% of TRALI cases, non–antibody factors or biological response modifiers are suggested to contribute the second hit, and these may possibly include lipid mediators, extracellular vesicles, and aged blood cells.
Neurobiological effects of physical exercise Cortisol and the psychological stress response Neurobiological_effects_of_physical_exercise > Effects on neurochemistry > Cortisol and the psychological stress response Individuals who have recently exercised exhibit improvements in stress coping behaviors. Aerobic exercise increases physical fitness and lowers neuroendocrine (i.e., HPA axis) reactivity and therefore reduces the biological response to psychological stress in humans (e.g., reduced cortisol release and attenuated heart rate response). Exercise also reverses stress-induced decreases in BDNF expression and signaling in the brain, thereby acting as a buffer against stress-related diseases like depression.
Tuberculosis diagnosis Nucleic acid amplification tests (NAAT) Tuberculosis_diagnosis > Nucleic acid amplification tests (NAAT) NAATs for TB are a heterogeneous group of tests that use either the polymerase chain reaction (PCR) technique or transcription-mediated amplification (TMA) or other forms of nucleic acid amplification methods to detect mycobacterial nucleic acid. These tests vary in which nucleic acid sequence they detect and vary in their accuracy. In the decade of the 2000s, the two most common commercially available tests were the amplified mycobacterium tuberculosis direct test (MTD, Gen-Probe) and Amplicor (Roche Diagnostics).
Word-sense disambiguation Unsupervised methods Word-sense_disambiguation > Approaches and methods > Unsupervised methods The relations (edges) in AutoExtend can either express the addition or similarity between its nodes. The former captures the intuition behind the offset calculus, while the latter defines the similarity between two nodes. In MSSA, an unsupervised disambiguation system uses the similarity between word senses in a fixed context window to select the most suitable word sense using a pre-trained word-embedding model and WordNet.
Glucokinase Clinical significance Glucokinase > Clinical significance Because insulin is one of, if not the most important, regulators of glucokinase synthesis, diabetes mellitus of all types diminishes glucokinase synthesis and activity by a variety of mechanisms. Glucokinase activity is sensitive to the oxidative stress of cells, especially the beta cells. At least 497 mutations of the human glucokinase gene GCK have been discovered, that can change the efficiency of glucose binding and phosphorylation, increasing or decreasing the sensitivity of beta cell insulin secretion in response to glucose, and producing clinically significant hyperglycemia or hypoglycemia.
Equatorial Counter Current Theoretical background Equatorial_Counter_Current > Theoretical background The NECC is a direct response to the meridional changes in the coriolis parameter and the wind stress curl near the Intertropical Convergence Zone (ITCZ). In part the NECC owes its existence to the fact that the ITCZ is not located at the equator, rather several degrees of latitude to the north. The rapid relative change in the coriolis parameter (a function of latitude) near the equator combined with the ITCZ being located north of the equator leads to similar rapid changes in the surface Ekman transport of the ocean and areas of convergence and divergence in the oceanic mixed layer. Using the larger Pacific basin as an example, the resulting dynamic height pattern consists of a trough at the equator, and ridge near 5° degrees north, a trough at 10°N, and finally a ridge closer to 20°N.
Ligand Common ligands Ligand_exchange > Common ligands Virtually every molecule and every ion can serve as a ligand for (or "coordinate to") metals. Monodentate ligands include virtually all anions and all simple Lewis bases. Thus, the halides and pseudohalides are important anionic ligands whereas ammonia, carbon monoxide, and water are particularly common charge-neutral ligands. Simple organic species are also very common, be they anionic (RO− and RCO−2) or neutral (R2O, R2S, R3−xNHx, and R3P).
Leveling effect Summary Leveling_effect Leveling effect or solvent leveling refers to the effect of solvent on the properties of acids and bases. The strength of a strong acid is limited ("leveled") by the basicity of the solvent. Similarly the strength of a strong base is leveled by the acidity of the solvent. When a strong acid is dissolved in water, it reacts with it to form hydronium ion (H3O+).
Gauge symmetry (mathematics) Summary Gauge_symmetry_(mathematics) For instance, this is the case of gauge symmetries in classical field theory. Yang–Mills gauge theory and gauge gravitation theory exemplify classical field theories with gauge symmetries.Gauge symmetries possess the following two peculiarities. Being Lagrangian symmetries, gauge symmetries of a Lagrangian satisfy Noether's first theorem, but the corresponding conserved current J μ {\displaystyle J^{\mu }} takes a particular superpotential form J μ = W μ + d ν U ν μ {\displaystyle J^{\mu }=W^{\mu }+d_{\nu }U^{\nu \mu }} where the first term W μ {\displaystyle W^{\mu }} vanishes on solutions of the Euler–Lagrange equations and the second one is a boundary term, where U ν μ {\displaystyle U^{\nu \mu }} is called a superpotential. In accordance with Noether's second theorem, there is one-to-one correspondence between the gauge symmetries of a Lagrangian and the Noether identities which the Euler–Lagrange operator satisfies. Consequently, gauge symmetries characterize the degeneracy of a Lagrangian system.Note that, in quantum field theory, a generating functional may fail to be invariant under gauge transformations, and gauge symmetries are replaced with the BRST symmetries, depending on ghosts and acting both on fields and ghosts.
Hermitian product Summary Sesquilinear_form In mathematics, a sesquilinear form is a generalization of a bilinear form that, in turn, is a generalization of the concept of the dot product of Euclidean space. A bilinear form is linear in each of its arguments, but a sesquilinear form allows one of the arguments to be "twisted" in a semilinear manner, thus the name; which originates from the Latin numerical prefix sesqui- meaning "one and a half". The basic concept of the dot product – producing a scalar from a pair of vectors – can be generalized by allowing a broader range of scalar values and, perhaps simultaneously, by widening the definition of a vector. A motivating special case is a sesquilinear form on a complex vector space, V. This is a map V × V → C that is linear in one argument and "twists" the linearity of the other argument by complex conjugation (referred to as being antilinear in the other argument).
Supersingular isogeny key exchange Summary Supersingular_isogeny_key_exchange Supersingular isogeny Diffie–Hellman key exchange (SIDH or SIKE) is an insecure proposal for a post-quantum cryptographic algorithm to establish a secret key between two parties over an untrusted communications channel. It is analogous to the Diffie–Hellman key exchange, but is based on walks in a supersingular isogeny graph and was designed to resist cryptanalytic attack by an adversary in possession of a quantum computer. Before it was broken, SIDH boasted one of the smallest key sizes of all post-quantum key exchanges; with compression, SIDH used 2688-bit public keys at a 128-bit quantum security level. SIDH also distinguishes itself from similar systems such as NTRU and Ring-LWE by supporting perfect forward secrecy, a property that prevents compromised long-term keys from compromising the confidentiality of old communication sessions.
Hydrogen-bond catalysis Stabilization of tetrahedral intermediates Hydrogen-bond_catalysis > Catalytic strategies > Stabilization of tetrahedral intermediates During the attack of the nucleophile, negative charge builds on the oxygen until the tetrahedral intermediate is reached. Therefore, the formally negative oxygen engages in a much stronger hydrogen bond than the starting carbonyl oxygen because of its increased negative charge. Energetically, this has the effect of lowering the intermediate and the transition state, thus accelerating the reaction.
Zvi Bern Summary Zvi_Bern Prior to this, it had been generally assumed that quantum gravitation from three loops resulted in uncontrollable divergences. In 2010, with his students Carrasco and Johansson, Bern found that diagrams for supersymmetric gravitational theories are equivalent to those of two copies of supersymmetric Yang-Mills theories (theories with gluons) which is known as double copy theory.
Evaluation methods Approaches Evaluation_methods > Approaches There exist several conceptually distinct ways of thinking about, designing, and conducting evaluation efforts. Many of the evaluation approaches in use today make truly unique contributions to solving important problems, while others refine existing approaches in some way.
Call graph Basic concepts Call_graph > Basic concepts A more precise call graph more precisely approximates the behavior of the real program, at the cost of taking longer to compute and more memory to store. The most precise call graph is fully context-sensitive, which means that for each procedure, the graph contains a separate node for each call stack that procedure can be activated with. A fully context-sensitive call graph is called a calling context tree.
Transformer (machine learning model) Methods for stabilizing training Transformer_(machine_learning_model) > Training > Methods for stabilizing training The plain transformer architecture had difficulty converging. In the original paper the authors recommended using learning rate warmup. That is, the learning rate should linearly scale up from 0 to maximal value for the first part of the training (usually recommended to be 2% of the total number of training steps), before decaying again. A 2020 paper found that using layer normalization before (instead of after) multiheaded attention and feedforward layers stabilizes training, not requiring learning rate warmup.
Inverse consistency Summary Inverse_consistency In image registration, inverse consistency measures the consistency of mappings between images produced by a registration algorithm. The inverse consistency error, introduced by Christiansen and Johnson in 2001, quantifies the distance between the composition of the mappings from each image to the other, produced by the registration procedure, and the identity function, and is used as a regularisation constraint in the loss function of many registration algorithms to enforce consistent mappings. Inverse consistency is necessary for good image registration but it is not sufficient, since a mapping can be perfectly consistent but not register the images at all.
Georg Limnaeus Career and Kepler connections Georg_Limnaeus > Career and Kepler connections By 1609, Kepler would develop and introduce his laws of planetary motion, which would subsequently play a major role in the development of Isaac Newton's law of universal gravitation, as has been noted by Newton. Limnaeus and his wife fell victim to the 1611 plague in Jena. == References ==
Strange loop Strangeness Strange_loop > Strangeness The "strangeness" of a strange loop comes from our way of perceiving, because we categorize our input in a small number of "symbols" (by which Hofstadter means groups of neurons standing for one thing in the outside world). So the difference between the video-feedback loop and our strange loops, our "I"s, is that while the former converts light to the same pattern on a screen, the latter categorizes a pattern and outputs its essence, so that as we get closer and closer to our essence, we get further down our strange loop.
Strong Customer Authentication Implementation Strong_Customer_Authentication > Implementation The European Banking Authority published an opinion on what approaches could constitute different "elements" of SCA.3-D Secure 2.0 can (but does not always) meet the requirements of SCA. 3-D Secure has implementations by Mastercard (Mastercard Identity Check) and Visa which are marketed as enabling SCA compliance. E-commerce merchants must update the payment flows in their websites and apps to support authentication. If authentication is not supported, many payments will be declined once SCA is fully implemented.
Artificial intelligence applications Reverse engineering AI_applications > Other fields of research > Reverse engineering Machine learning is used in diverse types of reverse engineering. For example, machine learning has been used to reverse engineer a composite material part, enabling unauthorized production of high quality parts, and for quickly understanding the behavior of malware. It can be used to reverse engineer artificial intelligence models. It can also design components by engaging in a type of reverse engineering of not-yet existent virtual components such as inverse molecular design for particular desired functionality or protein design for prespecified functional sites. Biological network reverse engineering could model interactions in a human understandable way, e.g. bas on time series data of gene expression levels.
Busy beaver Examples Busy_Beaver_Number > Examples These are tables of rules for the Turing machines that generate Σ(1) and S(1), Σ(2) and S(2), Σ(3) (but not S(3)), Σ(4) and S(4), and the best known lower bound for Σ(5) and S(5), and Σ(6) and S(6). For other visualizations, In the tables, columns represent the current state and rows represent the current symbol read from the tape. Each table entry is a string of three characters, indicating the symbol to write onto the tape, the direction to move, and the new state (in that order). The halt state is shown as H. Each machine begins in state A with an infinite tape that contains all 0s.
Benacerraf's identification problem Historical motivations Benacerraf's_identification_problem > Historical motivations Contrarily, mathematical nominalism denies the existence of any such abstract objects in the ontology of mathematics. In the late 19th and early 20th century, a number of anti-Platonist programs gained in popularity. These included intuitionism, formalism, and predicativism.
Privacy in education Medical records Privacy_in_education > Privacy in higher education > Medical records Minnesota law attempted to obtain a "written general authorization for such release from the patient" as a form to impede the activities of researchers or providers to share information without given consent. Hospitals in Minnesota even made brochures that highlight patient's rights to confidentiality and that they can give consent in writing if they allow for their medical records to be released outside of the facility. Thus, the law required health care providers to obtain a written consent and authorization from patients in order for medical records to be released and used for research.
Turing's proof Details of second proof Turing's_proof > Summary of the proofs > Details of second proof Now, what happens when we apply E to G itself? As we can apply the same process for determining if M prints 1 infinitely often. When we combine these processes, we can determine that M does, or does not, go on printing 1's and 0's ad infinitum.
Graph (abstract data type) Distributed memory Graph_representation > Parallel representations > Distributed memory In the distributed memory model, the usual approach is to partition the vertex set V {\displaystyle V} of the graph into p {\displaystyle p} sets V 0 , … , V p − 1 {\displaystyle V_{0},\dots ,V_{p-1}} . Here, p {\displaystyle p} is the amount of available processing elements (PE). The vertex set partitions are then distributed to the PEs with matching index, additionally to the corresponding edges. Every PE has its own subgraph representation, where edges with an endpoint in another partition require special attention.
Bitmap Index Summary Bitmap_Index Bitmap indexes use bit arrays (commonly called bitmaps) and answer queries by performing bitwise logical operations on these bitmaps. Bitmap indexes have a significant space and performance advantage over other structures for query of such data. Their drawback is they are less efficient than the traditional B-tree indexes for columns whose data is frequently updated: consequently, they are more often employed in read-only systems that are specialized for fast query - e.g., data warehouses, and generally unsuitable for online transaction processing applications. Some researchers argue that bitmap indexes are also useful for moderate or even high-cardinality data (e.g., unique-valued data) which is accessed in a read-only manner, and queries access multiple bitmap-indexed columns using the AND, OR or XOR operators extensively.Bitmap indexes are also useful in data warehousing applications for joining a large fact table to smaller dimension tables such as those arranged in a star schema.
Light-front computational methods Renormalization group Light-front_computational_methods > Renormalization group Once the required set of parameters is known, one can establish a set of observables that are sufficient to define the cutoff dependence of the required set. The observables can have any finite scale μ {\displaystyle \mu } , and one can use any scale μ {\displaystyle \mu } to define the parameters p ( Λ ) {\displaystyle p(\Lambda )} , up to their finite parts that must be fitted to experiment, including features such as the observed symmetries. Thus, not only the possibility that a renormalization group of the first type may exist can be understood, but also the alternative situations are found where the set of required cutoff dependent parameters does not have to be finite.
Tamper-evident technology Physical security Tamper-evident_technology > Physical security Security seals are commonly employed on devices such as electronic voting machines in an attempt to detect tampering. However, testing by Argonne National Laboratory and others demonstrates that existing seals can usually be quickly defeated by a trained person using low-tech methods.
Accounting method Summary Accounting_methods A basis of accounting is the time various financial transactions are recorded. The cash basis (EU VAT vocabulary cash accounting) and the accrual basis are the two primary methods of tracking income and expenses in accounting. Both can be used in a range of situations, from the accounts of a whole country or a large corporation to those of a small business or an individual. In many cases, regulatory bodies require individuals, businesses or corporations to use one method or the other. When this is not the case, the choice of which to use is an important decision, as both methods have advantages and disadvantages.
Complex projective line Applications Extended_complex_plane > Applications The Riemann sphere has been suggested as a relativistic model for the celestial sphere. In string theory, the worldsheets of strings are Riemann surfaces, and the Riemann sphere, being the simplest Riemann surface, plays a significant role. It is also important in twistor theory.
Distribution transformer Summary Pole_mount_transformer If the distribution lines are located at ground level or underground, distribution transformers are mounted on concrete pads and locked in steel cases, thus known as distribution tap pad-mount transformers. Distribution transformers normally have ratings less than 200 kVA, although some national standards can allow for units up to 5000 kVA to be described as distribution transformers. Since distribution transformers are energized for 24 hours a day (even when they don't carry any load), reducing iron losses has an important role in their design.
Synaptic tagging mRNA trafficking to the dendritic spine and cytoskeleton Synaptic_tagging > mRNA trafficking to the dendritic spine and cytoskeleton Beginning with transcription, mRNA molecules are potentially modified via alternate splicing of exons and introns. The alternate splicing mechanisms allow cells to produce a diverse set of proteins from a single gene within the genome. Recent developments in next-generation sequencing have allowed for greater understanding of the diversity eukaryotic cells achieve through splice variants.Transcribed mRNA must reach the intended dendritic spine for the spine to express L-LTP.
Data validation and reconciliation Data reconciliation Data_validation_and_reconciliation > Data reconciliation Additionally, each least squares term is weighted by the standard deviation of the corresponding measurement. The standard deviation is related to the accuracy of the measurement. For example, at a 95% confidence level, the standard deviation is about half the accuracy.
List of orbits Special classifications List_of_orbits > Classifications > Special classifications Planned orbit for the NASA Lunar Gateway in circa 2024, as a highly-elliptical seven-day near-rectilinear halo orbit around the Moon, which would bring the small space station within 3,000 kilometers (1,900 mi) of the lunar north pole at closest approach and as far away as 70,000 kilometers (43,000 mi) over the lunar south pole. Distant retrograde orbit (DRO): A stable circular retrograde orbit (usually referring to Lunar Distant Retrograde Orbit). Stability means that satellites in DRO do not need to use station keeping propellant to stay in orbit.
Block (periodic table) p-block G-block_group > Characteristics > p-block The p-block, with the p standing for "principal" and azimuthal quantum number 1, is on the right side of the standard periodic table and encompasses elements in groups 13 to 18. Their general electronic configuration is ns2 np1–6. Helium, though being the first element in group 18, is not included in the p-block. Each row of the table has a place for six p-elements except for the first row (which has none).
Volumetric analysis Measuring the endpoint of a titration Volumetric_titration > Measuring the endpoint of a titration Amperometry: Measures the current produced by the titration reaction as a result of the oxidation or reduction of the analyte. The endpoint is detected as a change in the current. This method is most useful when the excess titrant can be reduced, as in the titration of halides with Ag+.
Rocket body Summary Rocket_launch A rocket (from Italian: rocchetto, lit. 'bobbin/spool') is a vehicle that uses jet propulsion to accelerate without using the surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely from propellant carried within the vehicle; therefore a rocket can fly in the vacuum of space.
Mathematical Tables and Other Aids to Computation Summary Mathematics_of_Computation Mathematics of Computation is a bimonthly mathematics journal focused on computational mathematics. It was established in 1943 as Mathematical Tables and Other Aids to Computation, obtaining its current name in 1960. Articles older than five years are available electronically free of charge.
Beta adrenergic receptor antagonist Medical uses Beta_blockers > Medical uses Large differences exist in the pharmacology of agents within the class, thus not all beta blockers are used for all indications listed below. Indications for beta blockers include: Angina pectoris (contraindicated for Prinzmetal's angina) Atrial fibrillation Cardiac arrhythmia Congestive heart failure Essential tremor Glaucoma (as eye drops, they decrease intraocular pressure by lowering aqueous humor secretion) Hypertension, although they are generally not preferred as an initial treatment Hyperthyroidism Migraine prophylaxis Mitral valve prolapse Myocardial infarction Phaeochromocytoma, in conjunction with α-blocker Postural orthostatic tachycardia syndrome Symptomatic control (tachycardia, tremor) in anxiety and hyperthyroidism Theophylline overdoseBeta blockers have also been used for: Acute aortic dissection Hypertrophic obstructive cardiomyopathy Long QT syndrome Marfan syndrome (treatment with propranolol slows progression of aortic dilation and its complications) Prevention of variceal bleeding in portal hypertension Possible mitigation of hyperhidrosis Social and other anxiety disorders Controversially, for reduction of perioperative mortality in non-cardiac surgery, but the best evidence suggests that they increase mortality when used this way
Vaccine adverse event Adverse events Vaccine_injury > Adverse events According to the U.S. Centers for Disease Control and Prevention, while "any vaccine can cause side effects", most side effects are minor, primarily including sore arms or a mild fever. Unlike most medical interventions vaccines are given to healthy people, where the risk of side effects is not as easily outweighed by the benefit of treating existing disease. As such, the safety of immunization interventions is taken very seriously by the scientific community, with constant monitoring of a number of data sources looking for patterns of adverse events.As the success of immunization programs increases and the incidence of disease decreases, public attention shifts away from the risks of disease to the risk of vaccination.
Water fight History Water_fight > History One still used ploy is to simply fill a wide-mouthed object (i.e. a bucket or pot) with water such that one can heave a wave of water towards another using one's arms. Though accuracy and range of this type of water attack is minimal, at close range, it is quite possible to significantly soak another. This form of basic water combat is still employed today, particularly in Thailand during the Songkran festival.
Red–black tree Pipelining Red–black_tree > Parallel algorithms > Parallel bulk operations > Pipelining Each application of these steps is called a stage. Since the length of the subsequences in S {\displaystyle S} is ∈ O ( \| I \| ) {\displaystyle \in O(\|I\|)} and in every stage the subsequences are being cut in half, the number of stages is ∈ O ( log ⁡ \| I \| ) {\displaystyle \in O(\log \|I\|)} .Since all stages move up the black levels of the tree, they can be parallelised in a pipeline. Once a stage has finished processing one black level, the next stage is able to move up and continue at that level.
TI-92 series TI-92 TI-92_series > TI-92 The TI-92 was originally released in 1995, and was the first symbolic calculator made by Texas Instruments. It came with a computer algebra system (CAS) based on Derive, geometry based on Cabri II, and was one of the first calculators to offer 3D graphing. The TI-92 was not allowed on most standardized tests due mostly to its QWERTY keyboard. Its larger size was also rather cumbersome compared to other graphing calculators.
Shear and moment diagrams Step 1: Compute the reaction forces and moments Shear_and_moment_diagram > Calculating shear force and bending moment > Step 1: Compute the reaction forces and moments The first step obtaining the bending moment and shear force equations is to determine the reaction forces. This is done using a free body diagram of the entire beam. The beam has three reaction forces, Ra, Rb at the two supports and Rc at the clamped end. The clamped end also has a reaction couple Mc.

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