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Metric System Summary Metric_unit A set of independent dimensions of nature is selected, in terms of which all natural quantities can be expressed, called base quantities. For each of these dimensions, a representative quantity is defined as a base unit of measure. The definition of base units has increasingly been realised in terms of fundamental natural phenomena, in preference to copies of physical artefacts.
Prenyltransferase Summary Prenyltransferase Prenyltransferases (PTs) are a class of enzymes that transfer allylic prenyl groups to acceptor molecules. Prenyl transferases commonly refer to isoprenyl diphosphate syntheses (IPPSs). Prenyltransferases are a functional category and include several enzyme groups that are evolutionarily independent. Prenyltransferases are commonly divided into two classes, cis (or Z) and trans (or E), depending upon the stereochemistry of the resulting products.
Vitamin K reaction Bone health Vitamin_K_reaction > Importance of vitamin K > Roles of vitamin K > Bone health Many proteins in our body depends on vitamin K especially in the bone by carboxylating an amino acid glutamic acid (Glu) to gamma carboxyglutamic acid (Gla). There are controversial results in many studies that suggest the reduction of bone fracture or and increase of bone fracture. Due to these varying results, there are no conclusion in the usage of vitamin K supplements for bone health.
Aluminium electrolytic capacitor Summary Aluminum_electrolytic_capacitor Special types are used for energy storage, for example in photoflash or strobe applications or for signal coupling in audio applications. Aluminum electrolytic capacitors are polarized capacitors because of their anodization principle. They can only be operated with DC voltage applied with the correct polarity. Operating the capacitor with wrong polarity or with AC voltage leads to a short circuit and can destroy the component. The exceptions is the bipolar aluminum electrolytic capacitor, which has a back-to-back configuration of two anodes in one case and can be used in AC applications.
Basal ganglia calcification Summary Basal_ganglia_disease These disorders are known as hypokinetic disorders. However, a disorder leading to abnormally low output of the basal ganglia leads to reduced inhibition, and thus excitation, of the thalamocortical projection neurons (VA and VL) which synapse onto the cortex. This situation leads to an inability to suppress unwanted movements.
Greedy number partitioning Complete greedy algorithm Greedy_number_partitioning > Complete greedy algorithm Traversing the tree in depth-first order requires only O(n) space, but might take O(kn) time. The runtime can be improved by using the greedy heuristic: in each level, develop first the branch in which the current number is put in the set with the smallest sum. This algorithm finds the greedy (LPT) solution first, but then proceeds to look for better solutions.
Object novelty recognition Selective learning Object_novelty_recognition > Research questions > Attention > Selective learning Thus, the earlier learning appears to affect which dimension, color or form, the animal will attend to.Other experiments have shown that after animals have learned to respond to one aspect of the environment responsiveness to other aspects is suppressed. In "blocking", for example, an animal is conditioned to respond to one stimulus ("A") by pairing that stimulus with reward or punishment. After the animal responds consistently to A, a second stimulus ("B") accompanies A on additional training trials. Later tests with the B stimulus alone elicit little response, suggesting that learning about B has been blocked by prior learning about A. This result supports the hypothesis that stimuli are neglected if they fail to provide new information. Thus, in the experiment just cited, the animal failed to attend to B because B added no information to that supplied by A. If true, this interpretation is an important insight into attentional processing, but this conclusion remains uncertain because blocking and several related phenomena can be explained by models of conditioning that do not invoke attention.
Photoionization detector Summary Photoionization_detector PIDs produce instantaneous readings, operate continuously, and are commonly used as detectors for gas chromatography or as hand-held portable instruments. Hand-held, battery-operated versions are widely used in military, industrial, and confined working facilities for health and safety. Their primary use is for monitoring possible worker exposure to volatile organic compounds (VOCs) such as solvents, fuels, degreasers, plastics & their precursors, heat transfer fluids, lubricants, etc. during manufacturing processes and waste handling. Portable PIDs are used for monitoring: Industrial hygiene and safety Environmental contamination and remediation Hazardous materials handling Ammonia detection Lower explosive limit measurements Arson investigation Indoor air quality Cleanroom facility maintenance
Hypostatic pneumonia Bacterial Bronchial_Pneumonia > Mechanisms > Bacterial A minority of types of bacteria such as Mycobacterium tuberculosis and Legionella pneumophila reach the lungs via contaminated airborne droplets. Bacteria can also spread via the blood. Once in the lungs, bacteria may invade the spaces between cells and between alveoli, where the macrophages and neutrophils (defensive white blood cells) attempt to inactivate the bacteria.
Magma differentiation Typical behaviours of magma chambers Magmatic_differentiation > Typical behaviours of magma chambers The higher viscosity means that, when melted, a granitic magma will tend to move in a larger concerted mass and be emplaced as a larger mass because it is less fluid and able to move. This is why granites tend to occur as large plutons, and mafic rocks as dikes and sills. Granites are cooler and are therefore less able to melt and assimilate country rocks.
Abstraction-Filtration-Comparison test Abstraction Abstraction-Filtration-Comparison_test > Abstraction-Filtration-Comparison > Abstraction The abstractions test was first developed by the Second Circuit for use in literary works, but in the AFC test, they outline how it might be applied to computer programs. The court identifies possible levels of abstraction that can be defined. In increasing order of abstraction; these are: individual instructions, groups of instructions organized into a "hierarchy of modules", the functions of the lowest-level modules, the functions of the higher-level modules, the "ultimate function" of the code.
Assistive technology Home automation Assistive_technology > Home automation The form of home automation called assistive domotics focuses on making it possible for elderly and disabled people to live independently. Home automation is becoming a viable option for the elderly and disabled who would prefer to stay in their own homes rather than move to a healthcare facility. This field uses much of the same technology and equipment as home automation for security, entertainment, and energy conservation but tailors it towards elderly and disabled users. For example, automated prompts and reminders utilize motion sensors and pre-recorded audio messages; an automated prompt in the kitchen may remind the resident to turn off the oven, and one by the front door may remind the resident to lock the door.
Multidimensional discrete convolution Approximation by FIR filter Multidimensional_discrete_convolution > Gaussian convolution > Approximation by FIR filter Gaussian convolution can be effectively approximated via implementation of a Finite impulse response (FIR) filter. The filter will be designed with truncated versions of the Gaussian. For a two-dimensional filter, the transfer function of such a filter would be defined as the following: H ( z 1 , z 2 ) = 1 s ( r 1 , r 2 ) ∑ n 1 = − r 1 r 1 ∑ n 2 = − r 2 r 2 G ( n 1 , n 2 ) z 1 − n 1 z 2 − n 2 {\displaystyle H(z_{1},z_{2})={\frac {1}{s(r_{1},r_{2})}}\sum _{n_{1}=-r_{1}}^{r_{1}}\sum _{n_{2}=-r_{2}}^{r_{2}}G(n_{1},n_{2}){z_{1}}^{-n_{1}}{z_{2}}^{-n_{2}}} where s ( r 1 , r 2 ) = ∑ n 1 = − r 1 r 1 ∑ n 2 = − r 2 r 2 G ( n 1 , n 2 ) {\displaystyle s(r_{1},r_{2})=\sum _{n_{1}=-r_{1}}^{r_{1}}\sum _{n_{2}=-r_{2}}^{r_{2}}G(n_{1},n_{2})} Choosing lower values for r 1 {\displaystyle r_{1}} and r 2 {\displaystyle r_{2}} will result in performing less computations, but will yield a less accurate approximation while choosing higher values will yield a more accurate approximation, but will require a greater number of computations.
Manufacturing tolerance Mechanical component tolerance Engineering_tolerance > Mechanical component tolerance Dimensional tolerance is related to, but different from fit in mechanical engineering, which is a designed-in clearance or interference between two parts. Tolerances are assigned to parts for manufacturing purposes, as boundaries for acceptable build. No machine can hold dimensions precisely to the nominal value, so there must be acceptable degrees of variation. If a part is manufactured, but has dimensions that are out of tolerance, it is not a usable part according to the design intent.
BCS superconductor Overview BCS_superconductor > Overview The BCS theory, however, requires only that the potential be attractive, regardless of its origin. In the BCS framework, superconductivity is a macroscopic effect which results from the condensation of Cooper pairs. These have some bosonic properties, and bosons, at sufficiently low temperature, can form a large Bose–Einstein condensate.
Axial parallelism Explanation Axial_parallelism > Explanation Early gyroscopes were used to demonstrate the principle, most notably the Foucault's gyroscope experiment. Prior to the invention of the gyroscope, it had been explained by scientists in various ways. Early modern astronomer David Gregory, a contemporary of Isaac Newton, wrote: To explain the Motion of the Celestial Bodies about their proper Axes, given in Position, and the Revolutions of them… If a Body be said to be moved about a given Axe, being in other respects not moved, that Axe is suppos'd to be unmov'd, and every point out of it to describe a Circle, to whose Plane the Axis is perpendicular. And for that reason, if a Body be carried along a line, and at the same time be revolved about a given Axe; the Axe, in all the time of the Body's motion, will continue parallel to it self.
Glossary of computer science S Glossary_of_computer_science > S Sequences can be finite, as in these examples, or infinite, such as the sequence of all even positive integers (2, 4, 6, ...). In computing and computer science, finite sequences are sometimes called strings, words or lists, the different names commonly corresponding to different ways to represent them in computer memory; infinite sequences are called streams. The empty sequence ( ) is included in most notions of sequence, but may be excluded depending on the context.
Mutualistic network Mathematical modeling Mutualistic_network > Mathematical modeling Mathematical treatments of mutualisms, like the study of mutualisms in general, has lagged behind those of predation, or predator-prey, consumer-resource, interactions. In models of mutualisms, the terms "type I" and "type II" functional responses refer to the linear and saturating relationships, respectively, between benefit provided to an individual of species 1 (y-axis) on the density of species 2 (x-axis).
Mathematical constant Apéry's constant ζ(3) Mathematical_constant > Constants in advanced mathematics > Apéry's constant ζ(3) Apery's constant is the sum of the series Apéry's constant is an irrational number and its numeric value is approximately 1.2020569. Despite being a special value of the Riemann zeta function, Apéry's constant arises naturally in a number of physical problems, including in the second- and third-order terms of the electron's gyromagnetic ratio, computed using quantum electrodynamics.
Video game controller Others Video_game_controllers > Variants > Others A train controller for a Taito bullet train sim has also been made for the Wii console. Mechanical motion tracking systems like Gametrak use cables attached to gloves for tracking position of physical elements in three-dimensional space in real time. The Gametrak mechanism contains a retracting cable reel and a small tubular guide arm from which the cable passes out.
Vector-valued function Parametric representation of a surface Vector-valued_functions > Parametric representation of a surface For a surface embedded in n-dimensional space, one similarly has the representation ( x 1 , x 2 , . . .
Interpersonal communication Relational control Interpersonal_communication > Theories > Relational patterns of interaction theory > Patterns of interaction > Relational control Relational control refers to who is in control within a relationship. The pattern of behavior between partners over time, not any individual's behavior, defines the control within a relationship. Patterns of behavior involve individuals' responses to others' assertions. There are three kinds of responses: One-down responses are submissive to, or accepting of, another's assertions. One-up responses are in opposition to, or counter, another's assertions. One-across responses are neutral in nature.
History of molecular biology General overview Discovery_of_DNA > General overview In 1940, George Beadle and Edward Tatum demonstrated the existence of a precise relationship between genes and proteins. In the course of their experiments connecting genetics with biochemistry, they switched from the genetics mainstay Drosophila to a more appropriate model organism, the fungus Neurospora; the construction and exploitation of new model organisms would become a recurring theme in the development of molecular biology. In 1944, Oswald Avery, working at the Rockefeller Institute of New York, demonstrated that genes are made up of DNA(see Avery–MacLeod–McCarty experiment).
Steady State Chemical engineering Steady_State > Applications > Chemical engineering In chemistry, thermodynamics, and other chemical engineering, a steady state is a situation in which all state variables are constant in spite of ongoing processes that strive to change them. For an entire system to be at steady state, i.e. for all state variables of a system to be constant, there must be a flow through the system (compare mass balance). One of the simplest examples of such a system is the case of a bathtub with the tap open but without the bottom plug: after a certain time the water flows in and out at the same rate, so the water level (the state variable being Volume) stabilizes and the system is at steady state. Of course the Volume stabilizing inside the tub depends on the size of the tub, the diameter of the exit hole and the flowrate of water in.
Signal integrity On-chip signal integrity Signal_integrity > On-chip signal integrity These noise sources on the one hand present a lower limit to the smallest signal that can be amplified, and on the other, define an upper limit to the useful amplification. In digital ICs, noise in a signal of interest arises primarily from coupling effects from switching of other signals. Increasing interconnect density has led to each wire having neighbors that are physically closer together, leading to increased crosstalk between neighboring nets.
Post-metallocene catalyst Catalysts based on late transition metals Post-metallocene_catalyst > Catalysts based on late transition metals and DuPont.The concept of bulky bis-imine ligands was extended to iron complexes Representative catalysts feature diiminopyridine ligands. These catalysts are highly active but do not promote chain walking.
History of molecular evolution Genetic load, the classical/balance controversy, and the measurement of heterozygosity History_of_molecular_evolution > Early history > Genetic load, the classical/balance controversy, and the measurement of heterozygosity Bruce Wallace, working with J. C. King, used the overdominance hypothesis to develop the balance position, which left a larger place for overdominance (where the heterozygous state of a gene is more fit than the homozygous states). In that case, heterosis is simply the result of the increased expression of heterozygote advantage. If overdominant loci are common, then a high level of heterozygosity would result from natural selection, and mutation-inducing radiation may in fact facilitate an increase in fitness due to overdominance.
Intel Active Management Technology Applications Quiet_System_Technology > Applications Detect suspicious network traffic. In laptop and desktop PCs, this feature allows a sys-admin to define the events that might indicate an inbound or outbound threat in a network packet header. In desktop PCs, this feature also supports detection of known and/or unknown threats (including slow- and fast-moving computer worms) in network traffic via time-based, heuristics-based filters.
Glossary of artificial intelligence D Glossary_of_artificial_intelligence > D diagnosis Concerned with the development of algorithms and techniques that are able to determine whether the behaviour of a system is correct. If the system is not functioning correctly, the algorithm should be able to determine, as accurately as possible, which part of the system is failing, and which kind of fault it is facing. The computation is based on observations, which provide information on the current behaviour.
Diffractive beam splitter Applications Diffractive_beam_splitter > Applications Normally, a diffractive beam splitter is used in tandem with a focusing lens so that the output beam array becomes an array of focused spots on a plane at a given distance from the lens, called the "working distance". The focal length of the lens, together with the separation angle between the beams, determines the separation distance between the focused spots. This simple optical set-up is used in a variety of high-power laser research and industrial applications that typically include: Laser scribing (solar cells) Glass dicing (LCD displays) Perforation (cigarette filters) Beam sampling (Power monitoring and control) 3-D motion sensing (Example) Medical/aesthetic applications (skin treatment)
Clinical neurophysiology Summary Clinical_neurophysiology Clinical neurophysiology is a medical specialty that studies the central and peripheral nervous systems through the recording of bioelectrical activity, whether spontaneous or stimulated. It encompasses both research regarding the pathophysiology along with clinical methods used to diagnose diseases involving both central and peripheral nervous systems. Examinations in the clinical neurophysiology field are not limited to tests conducted in a laboratory. It is thought of as an extension of a neurologic consultation.
Activation energy Negative activation energy Energy_barrier > Negative activation energy Increasing the temperature leads to a reduced probability of the colliding molecules capturing one another (with more glancing collisions not leading to reaction as the higher momentum carries the colliding particles out of the potential well), expressed as a reaction cross section that decreases with increasing temperature. Such a situation no longer leads itself to direct interpretations as the height of a potential barrier.Some multistep reactions can also have apparent negative activation energies. For example, the overall rate constant k for a two-step reaction A ⇌ B, B → C is given by k = k2K1, where k2 is the rate constant of the rate-limiting slow second step and K1 is the equilibrium constant of the rapid first step.
Data model diagram Database model Data_models > Types > Database model The network data model is an abstraction of the design concept used in the implementation of databases. Relational model is a database model based on first-order predicate logic. Its core idea is to describe a database as a collection of predicates over a finite set of predicate variables, describing constraints on the possible values and combinations of values.
Set theorist Objections to set theory Axiomatic_set_theories > Objections to set theory Topos theory can interpret various alternatives to that theory, such as constructivism, finite set theory, and computable set theory. Topoi also give a natural setting for forcing and discussions of the independence of choice from ZF, as well as providing the framework for pointless topology and Stone spaces.An active area of research is the univalent foundations and related to it homotopy type theory. Within homotopy type theory, a set may be regarded as a homotopy 0-type, with universal properties of sets arising from the inductive and recursive properties of higher inductive types.
Thermoelectric power source Uses Thermoelectric_generator > Uses Every human activity, transport and industrial process generates waste heat, being possible to harvest residual energy from cars, aircraft, ships, industries and the human body. From cars the main source of energy is the exhaust gas. Harvesting that heat energy using a thermoelectric generator can increase the fuel efficiency of the car.
Uniform flow Summary Full_potential_equation In fluid dynamics, potential flow (or ideal flow) describes the velocity field as the gradient of a scalar function: the velocity potential. As a result, a potential flow is characterized by an irrotational velocity field, which is a valid approximation for several applications. The irrotationality of a potential flow is due to the curl of the gradient of a scalar always being equal to zero. In the case of an incompressible flow the velocity potential satisfies Laplace's equation, and potential theory is applicable.
Medical history Review of systems Medical_history > Review of systems Gastrointestinal system (change in weight, flatulence and heartburn, dysphagia, odynophagia, hematemesis, melena, hematochezia, abdominal pain, vomiting, bowel habit). Genitourinary system (frequency in urination, pain with micturition (dysuria), urine color, any urethral discharge, altered bladder control like urgency in urination or incontinence, menstruation and sexual activity). Nervous system (Headache, loss of consciousness, dizziness and vertigo, speech and related functions like reading and writing skills and memory).
Neumann–Dirichlet method Summary Neumann–Dirichlet_method In mathematics, the Neumann–Dirichlet method is a domain decomposition preconditioner which involves solving Neumann boundary value problem on one subdomain and Dirichlet boundary value problem on another, adjacent across the interface between the subdomains. On a problem with many subdomains organized in a rectangular mesh, the subdomains are assigned Neumann or Dirichlet problems in a checkerboard fashion.
Performance appraisal Judgmental evaluation Performance_appraisal > Methods of collecting data > Judgmental evaluation Judgmental evaluation appears to be a collection of methods, and as such, could be considered a methodology. A common approach to obtaining PAs is by means of raters. Because the raters are human, some error will always be present in the data. The most common types of error are leniency errors, central tendency errors, and errors resulting from the halo effect.
Formulas for generating Pythagorean triples Generating triples using quadratic equations Formulas_for_generating_Pythagorean_triples > Generating triples using quadratic equations There are several methods for defining quadratic equations for calculating each leg of a Pythagorean triple. A simple method is to modify the standard Euclid equation by adding a variable x to each m and n pair. The m, n pair is treated as a constant while the value of x is varied to produce a "family" of triples based on the selected triple. An arbitrary coefficient can be placed in front of the "x" value on either m or n, which causes the resulting equation to systematically "skip" through the triples.
Point groups in four dimensions Duoprismatic symmetry Point_groups_in_four_dimensions > Notation for groups > Duoprismatic symmetry The 4–4 duoprism has this extended symmetry, . The chiral extended group is ]+, order 64. Extended chiral subgroup is ], order 64, with rotoreflection generators.
C2H6OS Summary C2H6OS The molecular formula C2H6OS (molar mass: 78.13 g/mol, exact mass: 78.0139 u) may refer to: Dimethyl sulfoxide (DMSO) 2-Mercaptoethanol, or β-mercaptoethanol
Connection coefficients In general relativity Connection_coefficients > Applications > In general relativity The Christoffel symbols find frequent use in Einstein's theory of general relativity, where spacetime is represented by a curved 4-dimensional Lorentz manifold with a Levi-Civita connection. The Einstein field equations—which determine the geometry of spacetime in the presence of matter—contain the Ricci tensor, and so calculating the Christoffel symbols is essential. Once the geometry is determined, the paths of particles and light beams are calculated by solving the geodesic equations in which the Christoffel symbols explicitly appear.
Thought Language of thought hypothesis Thought > Theories of thinking > Inner speech theory > Language of thought hypothesis This applies to thought since human beings are capable of entertaining an infinite number of distinct thoughts even though their mental capacities are quite limited. Other characteristic features of thinking include systematicity and inferential coherence. Fodor argues that the language of thought hypothesis is true as it explains how thought can have these features and because there is no good alternative explanation.
Defining equation (physical chemistry) Notes on nomenclature Defining_equation_(physical_chemistry) > Notes on nomenclature The labeling is arbitrary in initial choice, but once chosen fixed for the calculation. If any reference to an actual entity (say hydrogen ions H+) or any entity at all (say X) is made, the quantity symbol q is followed by curved ( ) brackets enclosing the molecular formula of X, i.e. q(X), or for a component i of a mixture q(Xi). No confusion should arise with the notation for a mathematical function.
SARS-CoV-2 vaccine Other types SARS-CoV-2_vaccine > Vaccine technologies > Other types Additional types of vaccines that are in clinical trials include virus-like particle vaccines, multiple DNA plasmid vaccines, at least two lentivirus vector vaccines, a conjugate vaccine, and a vesicular stomatitis virus displaying the SARS‑CoV‑2 spike protein.Scientists investigated whether existing vaccines for unrelated conditions could prime the immune system and lessen the severity of COVID‑19 infections. There is experimental evidence that the BCG vaccine for tuberculosis has non-specific effects on the immune system, but no evidence that this vaccine is effective against COVID‑19.
Dynamic list Linked lists vs. dynamic arrays Dynamic_list > Tradeoffs > Linked lists vs. dynamic arrays Once the nth person is reached, one should remove them from the circle and have the members close the circle. The process is repeated until only one person is left. That person wins the election.
Regularization (physics) Overview Regularization_(physics) > Overview Regularization procedures deal with infinite, divergent, and nonsensical expressions by introducing an auxiliary concept of a regulator (for example, the minimal distance ϵ {\displaystyle \epsilon } in space which is useful, in case the divergences arise from short-distance physical effects). The correct physical result is obtained in the limit in which the regulator goes away (in our example, ϵ → 0 {\displaystyle \epsilon \to 0} ), but the virtue of the regulator is that for its finite value, the result is finite. However, the result usually includes terms proportional to expressions like 1 / ϵ {\displaystyle 1/\epsilon } which are not well-defined in the limit ϵ → 0 {\displaystyle \epsilon \to 0} . Regularization is the first step towards obtaining a completely finite and meaningful result; in quantum field theory it must be usually followed by a related, but independent technique called renormalization.
Osmolyte Summary Osmolyte These molecules are involved in counteracting the effects of osmotic stress, which occurs when there are fluctuations in the concentration of solutes (such as ions and sugars) inside and outside cells. Osmolytes help cells adapt to changing osmotic conditions, thereby ensuring their survival and functionality. Osmolytes also interact with the constituents of the cell, e.g., they influence protein folding. Common osmolytes include amino acids, sugars and polyols, methylamines, methylsulfonium compounds, and urea.
By inspection Philosophy of mathematics Angle_chasing > Philosophy of mathematics rigor (rigour) The act of establishing a mathematical result using indisputable logic, rather than informal descriptive argument. Rigor is a cornerstone quality of mathematics, and can play an important role in preventing mathematics from degenerating into fallacies. well-behaved An object is well-behaved (in contrast with being pathological) if it satisfies certain prevailing regularity properties, or if it conforms to mathematical intuition (even though intuition can often suggest opposite behaviors as well). In some occasions (e.g., analysis), the term "smooth" can also be used to the same effect.
Goal-oriented inference How it works Backward_reasoning > How it works Backward chaining starts with a list of goals (or a hypothesis) and works backwards from the consequent to the antecedent to see if any data supports any of these consequents. An inference engine using backward chaining would search the inference rules until it finds one with a consequent (Then clause) that matches a desired goal. If the antecedent (If clause) of that rule is not known to be true, then it is added to the list of goals (for one's goal to be confirmed one must also provide data that confirms this new rule).
Motor-CAD Summary Motor-CAD A wide range of housing types can be modelled. The Lab module works with the EMag and Therm modules to help develop new design concepts. It provides efficiency mapping and duty cycle / drive cycle transient outputs within a few minutes.
Metaphase II Phases Metaphase_II > Phases Meiosis I and II are each divided into prophase, metaphase, anaphase, and telophase stages, similar in purpose to their analogous subphases in the mitotic cell cycle. Therefore, meiosis includes the stages of meiosis I (prophase I, metaphase I, anaphase I, telophase I) and meiosis II (prophase II, metaphase II, anaphase II, telophase II). During meiosis, specific genes are more highly transcribed. In addition to strong meiotic stage-specific expression of mRNA, there are also pervasive translational controls (e.g. selective usage of preformed mRNA), regulating the ultimate meiotic stage-specific protein expression of genes during meiosis. Thus, both transcriptional and translational controls determine the broad restructuring of meiotic cells needed to carry out meiosis.
Circulation evaporator Physical characteristics Circulation_evaporator > Main characteristics > Physical characteristics Forced/Natural Circulation Evaporation is used when boiling of base liquids is undesired. It was developed specifically for processing and separation of liquids in which crystallising and scaling occurs. The evaporator uses separate parts to create the overall system; a heat exchanger, separation tank and for the forced circulation system (as opposed to the natural circulation system) a circulation pump are standard although can be subject to change depending on the liquids properties of the mixtures being separated and specific design. The units in the heat exchanger (where thermal transfer takes place) are called the heating units or calandria (for single tube heat exchangers).
Gene–environment correlation Definition Gene–environment_correlation > Definition Biological parents also pass on genetic material to their children. When the children's genotype also influences their behavioral or cognitive outcomes, the result can be a spurious relationship between environment and outcome. For example, because parents who have histories of antisocial behavior (which is moderately heritable) are at elevated risk of abusing their children, a case can be made for saying that maltreatment may be a marker for genetic risk that parents transmit to children rather than a causal risk factor for children’s conduct problems.
Choice modeling Constructing an experimental design that is appropriate for those attributes and levels, either from a design catalogue, or via a software program Discrete_Choice_Modelling > Designing a choice model > Constructing an experimental design that is appropriate for those attributes and levels, either from a design catalogue, or via a software program The best design depends on the objectives of the exercise. It is the experimental design that drives the experiment and the ultimate capabilities of the model. Many very efficient designs exist in the public domain that allow near optimal experiments to be performed.
Random variables Continuous random variable Random_quantity > Examples > Continuous random variable We could represent these directions by North, West, East, South, Southeast, etc. However, it is commonly more convenient to map the sample space to a random variable which takes values which are real numbers. This can be done, for example, by mapping a direction to a bearing in degrees clockwise from North. The random variable then takes values which are real numbers from the interval is 1⁄2.
Cossee-Arlman mechanism Publications of historic interest Cossee–Arlman_mechanism > Publications of historic interest 145 (3668): 235–246. doi:10.1002/macp.1971.021450119. Cossee, P. J.
GraphQL Type system GraphQL > Design > Type system The root type of a GraphQL schema, Query by default, contains all of the fields that can be queried. Other types define the objects and fields that the GraphQL server can return. There are several base types, called scalars, to represent things like strings, numbers, and IDs. Fields are defined as nullable by default, and a trailing exclamation mark can be used to make a field non-nullable (required). A field can be defined as a list by wrapping the field's type in square brackets (for example, authors: ).
Marginal operator Relevant and irrelevant operators and universality classes Renormalization_Group_Theory > Relevant and irrelevant operators and universality classes As an example, in microscopic physics, to describe a system consisting of a mole of carbon-12 atoms we need of the order of 1023 (the Avogadro number) variables, while to describe it as a macroscopic system (12 grams of carbon-12) we only need a few. Before Wilson's RG approach, there was an astonishing empirical fact to explain: The coincidence of the critical exponents (i.e., the exponents of the reduced-temperature dependence of several quantities near a second order phase transition) in very disparate phenomena, such as magnetic systems, superfluid transition (Lambda transition), alloy physics, etc. So in general, thermodynamic features of a system near a phase transition depend only on a small number of variables, such as the dimensionality and symmetry, but are insensitive to details of the underlying microscopic properties of the system. This coincidence of critical exponents for ostensibly quite different physical systems, called universality, is easily explained using the renormalization group, by demonstrating that the differences in phenomena among the individual fine-scale components are determined by irrelevant observables, while the relevant observables are shared in common. Hence many macroscopic phenomena may be grouped into a small set of universality classes, specified by the shared sets of relevant observables.
Logic family Transistor–transistor logic (TTL) Logic_family > Transistor–transistor logic (TTL) In TTL logic, bipolar junction transistors perform the logic and amplifying functions. The first transistor–transistor logic family of integrated circuits was introduced by Sylvania as Sylvania Universal High–Level Logic (SUHL) in 1963. Texas Instruments introduced the 7400 series TTL family in 1964. Transistor–transistor logic uses bipolar transistors to form its integrated circuits.
Knightian uncertainty Summary Knightian_uncertainty Whilst Frank Knight's seminal book elaborated the problem, his focus was on how uncertainty generates imperfect market structures and explains actual profits. Work on estimating and mitigating uncertainty was continued by G. L. S. Shackle who later followed up with Potential Surprise Theory. However, the concept is largely informal and there is no single best formal system of probability and belief to represent Knightian uncertainty. Economists and management scientists continue to look at practical methodologies for decision under different types of uncertainty.
Heat sink Surface color Heat_sink > Design factors > Surface color A shiny metal surface has low emissivity. The emissivity of a material is tremendously frequency-dependent and is related to absorptivity (of which shiny metal surfaces have very little). For most materials, the emissivity in the visible spectrum is similar to the emissivity in the infrared spectrum; however, there are exceptions – notably, certain metal oxides that are used as "selective surfaces". In vacuum or outer space, there is no convective heat transfer, thus in these environments, radiation is the only factor governing heat flow between the heat sink and the environment. For a satellite in space, a 100 °C (373 K) surface facing the Sun will absorb a lot of radiant heat, because the Sun's surface temperature is nearly 6000 K, whereas the same surface facing deep space will radiate a lot of heat, since deep space has an effective temperature of only several Kelvin.
Ornstein isomorphism theorem Summary Bernoulli_flow In mathematics, the Ornstein isomorphism theorem is a deep result in ergodic theory. It states that if two Bernoulli schemes have the same Kolmogorov entropy, then they are isomorphic. The result, given by Donald Ornstein in 1970, is important because it states that many systems previously believed to be unrelated are in fact isomorphic; these include all finite stationary stochastic processes, including Markov chains and subshifts of finite type, Anosov flows and Sinai's billiards, ergodic automorphisms of the n-torus, and the continued fraction transform.
Chronic Fatigue By mechanism Neurological_fatigue > Classification > By mechanism The mechanisms that cause fatigue are not well understood.
Weyr canonical form Definition Weyr_canonical_form > Definitions > Definition Let W {\displaystyle W} be a square matrix and let λ 1 , … , λ k {\displaystyle \lambda _{1},\ldots ,\lambda _{k}} be the distinct eigenvalues of W {\displaystyle W} . We say that W {\displaystyle W} is in Weyr form (or is a Weyr matrix) if W {\displaystyle W} has the following form: where W i {\displaystyle W_{i}} is a basic Weyr matrix with eigenvalue λ i {\displaystyle \lambda _{i}} for i = 1 , … , k {\displaystyle i=1,\ldots ,k} .
Heap feng shui Operation Heap_feng_shui > Operation The term is general and can be used to describe a variety of techniques for bypassing heap protection strategies. The paper often credited with naming the technique, "Heap Feng Shui in JavaScript", used it to refer to an exploit in which a dangling pointer was aligned with a portion of an attacker-controlled chunk. However, it has also found usage in capture the flag events to describe attacks that exploit characteristics of heap layout, such as the spacing between chunks.
Antilag system Using an MGU-H (Motor Generator Unit - Heat) to eliminate turbo lag Antilag_system > Methods > Using an MGU-H (Motor Generator Unit - Heat) to eliminate turbo lag Modern Formula One power units are turbocharged, six cylinder engines in V formation, with an additional hybrid system. The hybrid system consists of two motor generator units. These units are referred to as; The "Motor Generator Unit - Kinetic" (MGU-K), and the "Motor Generator Unit - Heat" (MGU-H) . To almost entirely eliminate turbo lag, the electrical energy that is stored in the car's onboard battery, is deployed (in part) to an electric motor that rapidly spins the compressor turbine.
Concerted evolution Causes Concerted_evolution > Causes Concerted evolution (phenomenon of duplicated genes) may often be caused by the genetic exchange known as gene conversion. This other phenomenon is known as the "non-reciprocal exchange of genetic material between homologous sequences. "Gene conservation can do a few things... Decrease mutational load Eliminate deleterious mutations Spread advantageous alleles...thus playing a role in concerted evolution. Gene conversion is also reliant on the gene sequences that are involved in the current process. Some entire gene sequences have undergone the process of concerted evolution whereas others have a more mosaic pattern where some genes are homogenized, and others diverge without this conversion.
Mise en abyme Summary Mise_en_abyme In Western art history, mise en abyme (French pronunciation: ; also mise en abîme), literally "placement in abyss", is a formal technique of placing a copy of an image within itself, often in a way that suggests an infinitely recurring sequence. In film theory and literary theory, it refers to the technique of inserting a story within a story. The term is derived from heraldry and literally means "placed into abyss". It was first appropriated for modern criticism by the French author André Gide.
Online transaction processing Systems design Online_transaction_processing > Systems design Buffer cache size: SQL statements should be tuned to use the database buffer cache to avoid unnecessary resource consumption. Dynamic allocation of space to tables and rollback segments Transaction processing monitors and the multi-threaded server: A transaction processing monitor is used for coordination of services. It is like an operating system and does the coordination at a high level of granularity and can span multiple computing devices. Partition (database): Partition use increases performance for sites that have regular transactions while still maintaining availability and security. Database tuning: With database tuning, an OLTP system can maximize its performance as efficiently and rapidly as possible.
Electronic Hamiltonian Summary Electronic_Hamiltonian Applications are restricted to small systems like the hydrogen molecule. Almost all calculations of molecular wavefunctions are based on the separation of the Coulomb Hamiltonian first devised by Born and Oppenheimer. The nuclear kinetic energy terms are omitted from the Coulomb Hamiltonian and one considers the remaining Hamiltonian as a Hamiltonian of electrons only.
AsciiMath Example AsciiMath > Example The well-known quadratic formula x = − b ± b 2 − 4 a c 2 a {\displaystyle x={\frac {-b\pm {\sqrt {b^{2}-4ac}}}{2a}}} looks like this in AsciiMath: x=(-b +- sqrt(b^2 – 4ac))/(2a)
Count–min sketch Summary Count–min_sketch In computing, the count–min sketch (CM sketch) is a probabilistic data structure that serves as a frequency table of events in a stream of data. It uses hash functions to map events to frequencies, but unlike a hash table uses only sub-linear space, at the expense of overcounting some events due to collisions. The count–min sketch was invented in 2003 by Graham Cormode and S. Muthu Muthukrishnan and described by them in a 2005 paper.Count–min sketches are essentially the same data structure as the counting Bloom filters introduced in 1998 by Fan et al. However, they are used differently and therefore sized differently: a count–min sketch typically has a sublinear number of cells, related to the desired approximation quality of the sketch, while a counting Bloom filter is more typically sized to match the number of elements in the set.
Deeplearning4j Machine Learning Model Server Deeplearning4j > Machine Learning Model Server What a Web server is to the Internet, a model server is to AI. Where a Web server receives an HTTP request and returns data about a Web site, a model server receives data, and returns a decision or prediction about that data: e.g. sent an image, a model server might return a label for that image, identifying faces or animals in photographs. The SKIL model server is able to import models from Python frameworks such as Tensorflow, Keras, Theano and CNTK, overcoming a major barrier in deploying deep learning models.
Sugarscape Origin Sugarscape > Origin To demonstrate their findings on the field of agent-based simulation, a model was created and distributed with their book on CD-ROM. The concept of this model has come to be known as "the Sugarscape model". Since then, the name "Sugarscape" has been used for agent-based models using rules similar to those defined by Epstein & Axtell.
Phenol Red Chemical structure and properties Phenol_Red > Chemical structure and properties A solution of phenol red is used as a pH indicator, often in cell culture. Its color exhibits a gradual transition from yellow (λmax = 443 nm) to red (λmax = 570 nm) over the pH range 6.8 to 8.2. Above pH 8.2, phenol red turns a bright pink (fuchsia) color.
KIT (gene) Anti-KIT therapies KIT_(gene) > Role in cancer > Anti-KIT therapies KIT is a proto-oncogene, meaning that overexpression or mutations of this protein can lead to cancer. Seminomas, a subtype of testicular germ cell tumors, frequently have activating mutations in exon 17 of KIT. In addition, the gene encoding KIT is frequently overexpressed and amplified in this tumor type, most commonly occurring as a single gene amplicon. Mutations of KIT have also been implicated in leukemia, a cancer of hematopoietic progenitors, melanoma, mast cell disease, and gastrointestinal stromal tumors (GISTs).
Stochastic simulation Probability distributions Stochastic_simulation > Discrete-event simulation > Probability distributions A probability distribution is used to describe the potential outcome of a random variable. Limits the outcomes where the variable can only take on discrete values.
Damp (structural) Summary Damp_(structural) Structural dampness is the presence of unwanted moisture in the structure of a building, either the result of intrusion from outside or condensation from within the structure. A high proportion of damp problems in buildings are caused by ambient climate dependent factors of condensation and rain penetration. Capillary penetration of fluid from the ground up through concrete or masonry is known as "rising damp" and is governed by the shape and porosity of the construction materials through which this evaporation-limited capillary penetration takes place.
Specific entropy Order and disorder Entropy > Approaches to understanding entropy > Order and disorder Entropy is often loosely associated with the amount of order or disorder, or of chaos, in a thermodynamic system. The traditional qualitative description of entropy is that it refers to changes in the status quo of the system and is a measure of "molecular disorder" and the amount of wasted energy in a dynamical energy transformation from one state or form to another. In this direction, several recent authors have derived exact entropy formulas to account for and measure disorder and order in atomic and molecular assemblies.
Atomic line spectra Crystals and extended materials Coherent_spectroscopy > Classification of methods > Type of material > Crystals and extended materials Acoustic and mechanical responses are due to collective motions as well. Pure crystals, though, can have distinct spectral transitions, and the crystal arrangement also has an effect on the observed molecular spectra. The regular lattice structure of crystals also scatters x-rays, electrons or neutrons allowing for crystallographic studies.
Insulin sensitivity Adaptive explanations Insulin_Resistance > History > Adaptive explanations Some scholars go as far as to claim that neither insulin resistance, nor obesity really are metabolic disorders per se, but simply adaptive responses to sustained caloric surplus, intended to protect bodily organs from lipotoxicity (unsafe levels of lipids in the bloodstream and tissues): "Obesity should therefore not be regarded as a pathology or disease, but rather as the normal, physiologic response to sustained caloric surplus... As a consequence of the high level of lipid accumulation in insulin target tissues including skeletal muscle and liver, it has been suggested that exclusion of glucose from lipid-laden cells is a compensatory defense against further accumulation of lipogenic substrate. "Other prevailing thoughts that insulin resistance can be an evolutionary adaptation include the thrifty gene hypothesis. This hypothesis raises the point that if there is a genetic component to insulin resistance and Type 2 diabetes, these phenotypes should be selected against. Yet, there has been an increase in mean insulin resistance in both the normoglycemic population as well as the diabetic population.J.V.
Microbiome in the Drosophila gut Gut compartmentalization Microbiome_in_the_Drosophila_gut > Gut compartmentalization The immune deficiency (IMD) pathway responds to bacterial infections and is activated by certain receptors (e.g., the peptidoglycan receptor protein PGRP-LC). These receptors and also other components of the Drosophila immune system such as Toll receptor and dDUOX pathway molecules control immune responses in ectodermal tissue of the anterior gut. Moreover, the anterior midgut is enriched in certain antimicrobial peptides (AMPs).
Warfarin sodium Chemistry Warfarin_rodenticide > Chemistry X-ray crystallographic studies of warfarin show that it exists in tautomeric form, as the cyclic hemiketal, which is formed from the 4-hydroxycoumarin and the ketone in the 3-position substituent. However, the existence of many 4-hydroxycoumadin anticoagulants (for example phenprocoumon) that possess no ketone group in the 3-substituent to form such a structure, suggests that the hemiketal must tautomerise to the 4-hydroxy form in order for warfarin to be active.
Radar meteorology Polarization Weather_radars > Data types > Polarization It should not be confused with the Doppler frequency shift, which is caused by the motion of the cloud and precipitation particles. Unlike the differential reflectivity, correlation coefficient and linear depolarization ratio, which are all dependent on reflected power, the differential phase is a "propagation effect." It is a very good estimator of rain rate and is not affected by attenuation.
Degree of freedom (statistics) General Degrees_of_freedom_(statistics) > In non-standard regression > General As another example, consider the existence of nearly duplicated observations. Naive application of classical formula, n − p, would lead to over-estimation of the residuals degree of freedom, as if each observation were independent. More realistically, though, the hat matrix H = X(X ' Σ−1 X)−1X ' Σ−1 would involve an observation covariance matrix Σ indicating the non-zero correlation among observations. The more general formulation of effective degree of freedom would result in a more realistic estimate for, e.g., the error variance σ2, which in its turn scales the unknown parameters' a posteriori standard deviation; the degree of freedom will also affect the expansion factor necessary to produce an error ellipse for a given confidence level.
Ground effect in aircraft Fixed-wing aircraft Ground_effect_(aerodynamics) > Explanations > Fixed-wing aircraft When an aircraft flies at or below approximately half the length of the aircraft's wingspan above the ground or water there occurs an often-noticeable ground effect. The result is lower induced drag on the aircraft. This is caused primarily by the ground or water obstructing the creation of wingtip vortices and interrupting downwash behind the wing.A wing generates lift by deflecting the oncoming airmass (relative wind) downward. The deflected or "turned" flow of air creates a resultant force on the wing in the opposite direction (Newton's 3rd law).
Acquired immunity Acquired immunity during pregnancy Adaptive_immune_response > Acquired immunity during pregnancy The second is that the fetus itself may promote local immunosuppression in the mother, perhaps by a process of active nutrient depletion. A more modern explanation for this induction of tolerance is that specific glycoproteins expressed in the uterus during pregnancy suppress the uterine immune response (see eu-FEDS). During pregnancy in viviparous mammals (all mammals except Monotremes), endogenous retroviruses (ERVs) are activated and produced in high quantities during the implantation of the embryo.
Methane pyrolysis Summary Methane_pyrolysis The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. Temperature can be understood as thermal vibration. At high temperatures, excessive vibration causes long chain molecules to break into smaller molecules.
OPC Foundation Summary OPC_Foundation The OPC Foundation (Open Platform Communications, formerly Object Linking and Embedding for Process Control) is an industry consortium that creates and maintains standards for open connectivity of industrial automation devices and systems, such as industrial control systems and process control generally. The OPC standards specify the communication of industrial process data, alarms and events, historical data and batch process data between sensors, instruments, controllers, software systems, and notification devices. The OPC Foundation started in 1994, as a task force comprising five industrial automation vendors (Fisher-Rosemount, Rockwell Automation, Opto 22, Intellution, and Intuitive Technology), with the purpose of creating a basic OLE for Process Control specification. OLE is a technology developed by Microsoft Corporation for the MS Windows operating system.
Data Modeling Overview Data_modelling > Overview Data modeling is a process used to define and analyze data requirements needed to support the business processes within the scope of corresponding information systems in organizations. Therefore, the process of data modeling involves professional data modelers working closely with business stakeholders, as well as potential users of the information system. There are three different types of data models produced while progressing from requirements to the actual database to be used for the information system. The data requirements are initially recorded as a conceptual data model which is essentially a set of technology independent specifications about the data and is used to discuss initial requirements with the business stakeholders.
Proteolysis Cell cycle regulation Proteolysis > Biological functions > Cellular regulation > Cell cycle regulation Cyclins are a group of proteins that activate kinases involved in cell division. The degradation of cyclins is the key step that governs the exit from mitosis and progress into the next cell cycle. Cyclins accumulate in the course the cell cycle, then abruptly disappear just before the anaphase of mitosis. The cyclins are removed via a ubiquitin-mediated proteolytic pathway.
Solar phenomena Coronal mass ejection (CME) Solar_activity > Types > Coronal mass ejection (CME) Magnetic reconnection is the name given to the rearrangement of magnetic field lines when two oppositely directed magnetic fields are brought together. This rearrangement is accompanied with a sudden release of energy stored in the original oppositely directed fields.When a CME impacts the Earth's magnetosphere, it temporarily deforms the Earth's magnetic field, changing the direction of compass needles and inducing large electrical ground currents in Earth itself; this is called a geomagnetic storm and it is a global phenomenon. CME impacts can induce magnetic reconnection in Earth's magnetotail (the midnight side of the magnetosphere); this launches protons and electrons downward toward Earth's atmosphere, where they form the aurora.
Operating table Properties and requirements made of an operating table Operating_table > Properties and requirements made of an operating table The radiolucent surface should be as large as possible to ensure the largest possible image without disruption. The padding of the table is also important, this must be both soft and radiolucent. Soft because it must distribute the pressure optimally otherwise the patient may suffer pressure ulcers which staff may be liable for.
Toxoplasmosis Parasitology Toxoplasmosis > Cause > Parasitology One method of apoptosis resistance is by disrupting pro-apoptosis effector proteins, such as BAX and BAK. To disrupt these proteins, T. gondii causes conformational changes to the proteins, which prevent the proteins from being transported to various cellular compartments where they initiate apoptosis events. T. gondii does not, however, cause downregulation of the pro-apoptosis effector proteins.T.
Linearly separable Support vector machines Linearly_separable > Support vector machines If such a hyperplane exists, it is known as the maximum-margin hyperplane and the linear classifier it defines is known as a maximum margin classifier. More formally, given some training data D {\displaystyle {\mathcal {D}}} , a set of n points of the form D = { ( x i , y i ) ∣ x i ∈ R p , y i ∈ { − 1 , 1 } } i = 1 n {\displaystyle {\mathcal {D}}=\left\{(\mathbf {x} _{i},y_{i})\mid \mathbf {x} _{i}\in \mathbb {R} ^{p},\,y_{i}\in \{-1,1\}\right\}_{i=1}^{n}} where the yi is either 1 or −1, indicating the set to which the point x i {\displaystyle \mathbf {x} _{i}} belongs. Each x i {\displaystyle \mathbf {x} _{i}} is a p-dimensional real vector.
Finite intersection property General sources Strong_finite_intersection_property > References > General sources Vol. 211. Berlin Heidelberg New York: Springer-Verlag.
Assistive Technology Industry Association Partners Assistive_Technology_Industry_Association > Partners ATIA partners with other organizations in the technology and disability fields to promote adoption and awareness of the ways that technology can benefit people with disabilities. Alliance Partners are: Alliance for Technology Access (ATA) American Federation for the Blind (AFB) American Occupational Therapy Association (AOTA) American Speech-Language-Hearing Association (ASHA) Assistive Technology in Higher Education Network (ATHEN) Association of Assistive Technology Act Programs (ATAP) Association on Higher Education and Disability (AHEAD) Center for Applied Special Technology (CAST) The Chicago Lighthouse DAISY Consortium Easter Seals Employment Resources, Inc. (ERI) Florida Diagnostic and Learning Resources System (FDLRS) Iowa Braille School (IBS) National Assistive Technology Technical Assistance Partnership (NATTAP) National Technical Institute for the Deaf (NTID) Pass It On Center (PIOC) Rehabilitation Engineering and Assistive Technology Society of North America (RESNA) State Leaders in Assistive Technology in Education (SLATE) The Technology and Media Division (TAM) of the Council for Exceptional Children (CEC)
Computable analysis Realisability Computable_analysis > Discussion > Realisability In the event that one is unhappy with using Turing machines (on the grounds that they are low level and somewhat arbitrary), there is a realisability topos called the Kleene–Vesley topos in which one can reduce computable analysis to constructive analysis. This constructive analysis includes everything that is valid in the Brouwer school, and not just the Bishop school. Additionally, a theorem in this school of constructive analysis is that not all real numbers are computable, which is constructively non-equivalent to there exist uncomputable numbers. This school of constructive analysis is therefore in direct contradiction to schools of constructive analysis — such as Markov's — which claim that all functions are computable. It ultimately shows that while constructive existence implies computability, it is in fact unproblematic — even useful — to assert that not every function is computable.

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