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Data Modeling Data models Data_Modeling > Topics > Data models This can lead to replication of data, data structure and functionality, together with the attendant costs of that duplication in development and maintenance. Therefore, data definitions should be made as explicit and easy to understand as possible to minimize misinterpretation and duplication. Data models for different systems are arbitrarily different.
Baby sign language Learning baby sign Baby_sign_language > Learning baby sign When words were produced by the child, they typically were ones that the child had already been gesturing for. This shows that gesture is directly linked to the words that children will produce.Symbolic gesture is the specific term that encompasses baby sign. This form of gesture aids in communication through the use of hand movements that represent an item or feeling.
Solarroller Summary Solarroller Configurations differences include: motor (number and output), wheels (number and size), and frame designsThis robot type always moves forwards. The motor drives one or more wheels. A "Solar Engine" circuit is used to feed the robot. Solarroller's speed is directly related to the amount of light robot registers on its optical sensor. Most are driven by an electronic "relaxation oscillator", in which a charge is accumulated in a capacitor while at rest and then suddenly released in the drive mechanism.
Macromolecular system Thermodynamics Supermolecular_chemistry > Control > Thermodynamics In the simplest case, p=q=1, the equilibrium can be written as H + G ⇋ H G {\displaystyle H+G\leftrightharpoons HG} The value of the equilibrium constant, K, for this reaction can, in principle, be determined by any of the techniques described below. Some examples are shown in the following table. The Gibbs free energy change, Δ G {\displaystyle \Delta G} , for this reaction is the sum of an enthalpy term, Δ H {\displaystyle \Delta H} and an entropy term T Δ S {\displaystyle T\Delta S} .
Wave particle duality History Three_wave_hypothesis > History : 211 The experimental evidence of particle-like momentum and energy seemingly contradicted the earlier work demonstrating wave-like interference of light. The contradictory evidence from electrons arrived in the opposite order. Many experiments by J. J. Thompson,: I:361 Robert Millikan,: I:89 and Charles Wilson: I:4 among others had shown that free electrons had particle properties, for instance the measurement of their mass by Thompson in 1897.
Computing science Artificial intelligence Computer_science > Fields > Applied computer science > Artificial intelligence Artificial intelligence (AI) aims to or is required to synthesize goal-orientated processes such as problem-solving, decision-making, environmental adaptation, learning, and communication found in humans and animals. From its origins in cybernetics and in the Dartmouth Conference (1956), artificial intelligence research has been necessarily cross-disciplinary, drawing on areas of expertise such as applied mathematics, symbolic logic, semiotics, electrical engineering, philosophy of mind, neurophysiology, and social intelligence. AI is associated in the popular mind with robotic development, but the main field of practical application has been as an embedded component in areas of software development, which require computational understanding. The starting point in the late 1940s was Alan Turing's question "Can computers think? ", and the question remains effectively unanswered, although the Turing test is still used to assess computer output on the scale of human intelligence. But the automation of evaluative and predictive tasks has been increasingly successful as a substitute for human monitoring and intervention in domains of computer application involving complex real-world data.
Dynamic similarity (Reynolds and Womersley numbers) Boundary layer thickness Dynamic_similarity_(Reynolds_and_Womersley_numbers) > Boundary layer thickness yields: δ 1 = μ ρ ω {\displaystyle {\delta }_{1}={\sqrt {\tfrac {\mu }{\rho \omega }}}\,\!} Adding a characteristic length (L) to both sides gives the ratio: L δ 1 = L ρ ω μ = L ω ν = N W {\displaystyle {\tfrac {L}{\delta _{1}}}=L{\sqrt {\tfrac {\rho \omega }{\mu }}}=L{\sqrt {\tfrac {\omega }{\nu }}}=N_{W}\,\!} Therefore, it can be seen that when the flow has a high Womersley Number the transient boundary layer thickness is very small, when compared to the characteristic length, which for circular vessels is the radius.
Covalently bonded History Covalently_bonded > History The term covalence in regard to bonding was first used in 1919 by Irving Langmuir in a Journal of the American Chemical Society article entitled "The Arrangement of Electrons in Atoms and Molecules". Langmuir wrote that "we shall denote by the term covalence the number of pairs of electrons that a given atom shares with its neighbors. "The idea of covalent bonding can be traced several years before 1919 to Gilbert N. Lewis, who in 1916 described the sharing of electron pairs between atoms.
OpenQASM Summary OpenQASM Open Quantum Assembly Language (OpenQASM; pronounced open kazm) is a programming language designed for describing quantum circuits and algorithms for execution on quantum computers. It is designed to be an intermediate representation that can be used by higher-level compilers to communicate with quantum hardware, and allows for the description of a wide range of quantum operations, as well as classical feed-forward flow control based on measurement outcomes. The language includes a mechanism for describing explicit timing of instructions, and allows for the attachment of low-level definitions to gates for tasks such as calibration. OpenQASM is not intended for general-purpose classical computation, and hardware implementations of the language may not support the full range of data manipulation described in the specification.
Varying speed of light Gravitational constant G Varying_speed_of_light > Relation to other constants and their variation > Gravitational constant G In 1937, Paul Dirac and others began investigating the consequences of natural constants changing with time. For example, Dirac proposed a change of only 5 parts in 1011 per year of the Newtonian constant of gravitation G to explain the relative weakness of the gravitational force compared to other fundamental forces. This has become known as the Dirac large numbers hypothesis. However, Richard Feynman showed that the gravitational constant most likely could not have changed this much in the past 4 billion years based on geological and solar system observations, although this may depend on assumptions about G varying in isolation. (See also strong equivalence principle.)
Metal–ligand multiple bond Reactivity explained through ligand hybridization Metal-ligand_multiple_bond > Reactivity explained through ligand hybridization Even the oxo can be sp2 or sp hybridized. The triply bonded oxo, similar to carbon monoxide, is partially positive at the oxygen atom and unreactive towards Brønsted acids at the oxygen atom. When such a complex is reduced, the triple bond can be converted to a double bond at which point the oxygen no longer bears a partial positive charge and is reactive towards acid.
Cross-validation (analytical chemistry) Summary Cross-validation_(analytical_chemistry) In analytical chemistry, cross-validation is an approach by which the sets of scientific data generated using two or more methods are critically assessed. The cross-validation can be categorized as either method validation or analytical data validation.
Oxygen saturation (medicine) Measurement Oxygen_saturation_(medicine) > Measurement An SaO2 (arterial oxygen saturation, as determined by an arterial blood gas test) value below 90% indicates hypoxemia (which can also be caused by anemia). Hypoxemia due to low SaO2 is indicated by cyanosis. Oxygen saturation can be measured in different tissues:
Heart chamber Influences Right_heart > Physiology > Heart rate > Influences However, as the atrial baroreceptors increase their rate of firing and as they stretch due to the increased blood pressure, the cardiac center responds by increasing sympathetic stimulation and inhibiting parasympathetic stimulation to increase heart rate. The opposite is also true. Chemoreceptors present in the carotid body or adjacent to the aorta in an aortic body respond to the blood's oxygen, carbon dioxide levels.
Class C share Price-to-Earnings Ratio (P/E Ratio) Class_C_share > Valuation Metrics of Class B Shares > Price-to-Earnings Ratio (P/E Ratio) This is the most common way to value a stock. It is represented by the stock price divided by the company’s most recent earnings per share (EPS). The lower the P/E ratio, the more attractive the amount of value for the share.This is because a high P/E ratio indicates that a stock’s price is expensive whereas a low P/E ratio indicates that the stock price is cheaper compared to its earnings. This ratio is important as it helps determine whether a stock is overvalued or \|undervalued.
Glassy phase Computational techniques Amorphous_solid > Characterization of amorphous solids > Computational techniques Simulation and modeling techniques are often combined with experimental methods to characterize structures of amorphous materials. Commonly used computational techniques include density functional theory, molecular dynamics, and reverse Monte Carlo.
Computer organization Cache Computer_organization > Microarchitectural concepts > Cache Previously, it didn't make much sense to build a pipeline that could run faster than the access latency of off-chip memory. Using on-chip cache memory instead, meant that a pipeline could run at the speed of the cache access latency, a much smaller length of time. This allowed the operating frequencies of processors to increase at a much faster rate than that of off-chip memory.
Enfish, LLC v. Microsoft Corp. Background Enfish,_LLC_v._Microsoft_Corp. > Background In a standard, conventional relational database, each entity (i.e., each type of thing) that is modeled is provided in a separate table. For instance, a relational model for a corporate file repository might include the following tables: document table, person table, and company table. The document table might contain information about stored documents, the person table might contain information about authors of the documents, and the company table might contain information about the companies that employ the persons.
List of textbooks on classical mechanics and quantum mechanics Classical mechanics List_of_textbooks_on_classical_mechanics_and_quantum_mechanics > Advanced undergraduate and graduate > Classical mechanics Translated by Sykes, J. B.; Bell, J. S. (3rd ed.). Elsevier.
Computer Simulation Technology CST Studio Suite Computer_Simulation_Technology > CST Studio Suite CST Studio Suite is a computational electromagnetics tool developed by Dassault Systèmes Simulia. It contains several different simulation methods, including the finite integration technique (FIT), finite element method (FEM), transmission line matrix (TLM), multilevel fast multipole method (MLFMM) and particle-in-cell (PIC), as well as multiphysics solvers for other domains of physics with links to electromagnetics.The predecessor to CST Studio Suite, MAFIA ("solving Maxwell's equations with the Finite Integration Algorithm"), was sold by CST, a university spin-off from TU Darmstadt founded in 1992 to commercialize the FIT method originally invented in 1977 by Thomas Weiland. Although the software was initially developed for particle accelerator laboratories, it found application in microwave engineering, and so FIT was implemented in CST Microwave Studio (CST MWS) in 1998, which became CST Studio Suite in 2005. CST was acquired by Dassault Systèmes in 2016, and since then CST Studio Suite has been a product of Simulia.
Computational indistinguishability Formal definition Computational_indistinguishability > Formal definition Let { D n } n ∈ N {\displaystyle \scriptstyle \{D_{n}\}_{n\in \mathbb {N} }} and { E n } n ∈ N {\displaystyle \scriptstyle \{E_{n}\}_{n\in \mathbb {N} }} be two distribution ensembles indexed by a security parameter n (which usually refers to the length of the input); we say they are computationally indistinguishable if for any non-uniform probabilistic polynomial time algorithm A, the following quantity is a negligible function in n: δ ( n ) = \| Pr x ← D n − Pr x ← E n \| . {\displaystyle \delta (n)=\left\|\Pr _{x\gets D_{n}}-\Pr _{x\gets E_{n}}\right\|.} denoted D n ≈ E n {\displaystyle D_{n}\approx E_{n}} . In other words, every efficient algorithm A's behavior does not significantly change when given samples according to Dn or En in the limit as n → ∞ {\displaystyle n\to \infty } . Another interpretation of computational indistinguishability, is that polynomial-time algorithms actively trying to distinguish between the two ensembles cannot do so: that any such algorithm will only perform negligibly better than if one were to just guess.
Autoimmune hepatitis Cause Autoimmune_hepatitis > Cause The prevailing theory for the development of autoimmune hepatitis is thought to be the interplay of genetic predisposition, an environmental trigger (virus, drugs, herbs, immunizations), and failure of the native immune system resulting in chronic inflammation of hepatocytes and subsequent fibrosis of the liver.There is no specific evidence of the cause. Sixty percent of patients have findings associated with chronic hepatitis but without serologic evidence of a viral infection. The disease is strongly associated with anti-smooth muscle autoantibodies.The exact genes and triggers responsible remain undefined, but studies show association of early-onset, severe disease with the HLA-DR3 serotype and late-onset disease with the HLA-DR4 serotype.
Greenhouse Effect Mars Greenhouse_warming > Bodies other than Earth > Mars Mars has about 70 times as much carbon dioxide as Earth, but experiences only a small greenhouse effect, about 6 K (11 °F). The greenhouse effect is small due to the lack of water vapor and the overall thinness of the atmosphere.The same radiative transfer calculations that predict warming on Earth accurately explain the temperature on Mars, given its atmospheric composition.
History of Maxwell's equations Relativity History_of_Maxwell's_equations > Relativity Maxwell's equations were an essential inspiration for the development of special relativity. Possibly the most important aspect was their denial of instantaneous action at a distance. Rather, according to them, forces are propagated at the velocity of light through the electromagnetic field. : 189 Maxwell's original equations are based on the idea that light travels through a sea of molecular vortices known as the "luminiferous aether", and that the speed of light has to be respective to the reference frame of this aether.
Causal models Independence conditions Causal_model > Associations > Independence conditions Conditioning on a variable involves analyzing the values of other variables for a given value of the conditioned variable. In the first example, conditioning on B {\displaystyle B} implies that observations for a given value of B {\displaystyle B} should show no dependence between A {\displaystyle A} and C {\displaystyle C} .
Nanoindentation Young's modulus Nanoindentation > Background > Young's modulus For a diamond indenter tip, E i {\displaystyle E_{i}} is 1140 GPa and ν i {\displaystyle \nu _{i}} is 0.07. Poisson’s ratio of the specimen, ν s {\displaystyle \nu _{s}} , generally varies between 0 and 0.5 for most materials (though it can be negative) and is typically around 0.3.
Natural Law Hobbes Natural_Law > History > English jurisprudence > Hobbes Breach of this law is called ingratitude. The fifth law is complaisance: that every man strive to accommodate himself to the rest. The observers of this law may be called sociable; the contrary, stubborn, insociable, forward, intractable.
Isothermal bulk modulus Interatomic potential and linear elasticity Bulk_modulus > Microscopic origin > Interatomic potential and linear elasticity Since linear elasticity is a direct result of interatomic interaction, it is related to the extension/compression of bonds. It can then be derived from the interatomic potential for crystalline materials. First, let us examine the potential energy of two interacting atoms. Starting from very far points, they will feel an attraction towards each other.
Journal of Machine Learning Research Summary Journal_of_Machine_Learning_Research The Journal of Machine Learning Research is a peer-reviewed open access scientific journal covering machine learning. It was established in 2000 and the first editor-in-chief was Leslie Kaelbling. The current editors-in-chief are Francis Bach (Inria) and David Blei (Columbia University).
Free recoil Calculating free recoil Free_recoil > Calculating free recoil vgu is the velocity of the small arm expressed in meters per second (m/s). vp is the velocity of the projectile expressed in meters per second (m/s). vc is the velocity of the powder charge expressed in meters per second (m/s). 1000 is the conversion factor to set the equation equal to kilograms.
Atlantic meridional overturning circulation Projections Atlantic_meridional_overturning_circulation > Projections : 19 Unlike the Fifth Assessment Report, it had only expressed medium confidence rather than high confidence in AMOC avoiding a collapse before the end of the century. This reduction in confidence was likely influenced by several review studies drawing attention to the circulation stability bias within general circulation models, as well as simplified ocean modelling studies suggesting that the AMOC may be more vulnerable to abrupt change than what the larger-scale models suggest.In 2022, a study performed modelling experiments with three climate models participating in Aerosol and Chemistry Model Intercomparison Project, and it found that very aggressive mitigation of air pollution like particulates and ground-level ozone could weaken AMOC circulation by 10% by the end of the century if it happened on its own, due to the reduction in climate-cooling stratospheric sulfur aerosols. The authors recommended pairing air pollution mitigation with the mitigation of methane emissions to avoid this outcome, as both methane (a strong warming agent) and sulfate aerosols (a cooling agent) are similarly short-lived in the atmosphere, and a simultaneous reduction of both would cancel out their effects.In 2022, an extensive assessment of all potential climate tipping points identified 16 plausible climate tipping points, including a collapse of the AMOC.
Data Modeling Semantic data modeling Data_modelling > Topics > Semantic data modeling The logical data structure of a DBMS, whether hierarchical, network, or relational, cannot totally satisfy the requirements for a conceptual definition of data because it is limited in scope and biased toward the implementation strategy employed by the DBMS. That is unless the semantic data model is implemented in the database on purpose, a choice which may slightly impact performance but generally vastly improves productivity. Therefore, the need to define data from a conceptual view has led to the development of semantic data modeling techniques. That is, techniques to define the meaning of data within the context of its interrelationships with other data.
Descriptional Complexity of Formal Systems Topics of the workshop Descriptional_Complexity_of_Formal_Systems > Topics of the workshop Typical topics include: various measures of descriptional complexity of automata, grammars, languages and of related systems trade-offs between descriptional complexity and mode of operation circuit complexity of Boolean functions and related measures succinctness of description of (finite) objects state complexity of finite automata descriptional complexity in resource-bounded or structure-bounded environments structural complexity descriptional complexity of formal systems for applications (e.g. software reliability, software and hardware testing, modelling of natural languages) descriptional complexity aspects of nature-motivated (bio-inspired) architectures and unconventional models of computing Kolmogorov–Chaitin complexity and descriptional complexityAs such, the topics of the conference overlap with those of the International Federation for Information Processing Working Group 1.2 on descriptional complexity.
Tensors in curvilinear coordinates The Jacobian Tensors_in_curvilinear_coordinates > Vector and tensor algebra in three-dimensional curvilinear coordinates > Coordinate transformations > The Jacobian As we now see that the Coordinates Z i {\displaystyle Z^{i}} and Z i ´ {\displaystyle Z^{\acute {i}}} are functions of each other, we can take the derivative of the coordinate variable Z i {\displaystyle Z^{i}} with respect to the coordinate variable Z i ´ {\displaystyle Z^{\acute {i}}} consider for i ´ , i = 1 , 2 , 3 {\displaystyle {\acute {i}},i=1,2,3} , these derivatives can be arranged in a matrix, say J {\displaystyle J} ,in which J i ´ i {\displaystyle J_{\acute {i}}^{i}} is the element in the i {\displaystyle i} -th row and i ´ {\displaystyle {\acute {i}}} -th column The resultant matrix is called the Jacobian matrix.
Fisher's exact test Purpose and scope Fisher's_exact_test > Purpose and scope The p-value from the test is computed as if the margins of the table are fixed, i.e. as if, in the tea-tasting example, Bristol knows the number of cups with each treatment (milk or tea first) and will therefore provide guesses with the correct number in each category. As pointed out by Fisher, this leads under a null hypothesis of independence to a hypergeometric distribution of the numbers in the cells of the table. With large samples, a chi-squared test (or better yet, a G-test) can be used in this situation.
Explained variation In principal component analysis Explained_variance > Special cases and generalized usage > In principal component analysis Explained variance is routinely used in principal component analysis. The relation to the Fraser–Kent information gain remains to be clarified.
Line regression Machine learning Regression_intercept > Applications > Machine learning Linear regression plays an important role in the subfield of artificial intelligence known as machine learning. The linear regression algorithm is one of the fundamental supervised machine-learning algorithms due to its relative simplicity and well-known properties.
Characterization of probability distributions Summary Characterization_of_probability_distributions On the probability space we define the space X = { X } {\displaystyle {\mathcal {X}}=\{X\}} of random variables with values in measurable metric space ( U , d u ) {\displaystyle (U,d_{u})} and the space Y = { Y } {\displaystyle {\mathcal {Y}}=\{Y\}} of random variables with values in measurable metric space ( V , d v ) {\displaystyle (V,d_{v})} . By characterizations of probability distributions we understand general problems of description of some set C {\displaystyle {\mathcal {C}}} in the space X {\displaystyle {\mathcal {X}}} by extracting the sets A ⊆ X {\displaystyle {\mathcal {A}}\subseteq {\mathcal {X}}} and B ⊆ Y {\displaystyle {\mathcal {B}}\subseteq {\mathcal {Y}}} which describe the properties of random variables X ∈ A {\displaystyle X\in {\mathcal {A}}} and their images Y = F X ∈ B {\displaystyle Y=\mathbf {F} X\in {\mathcal {B}}} , obtained by means of a specially chosen mapping F: X → Y {\displaystyle \mathbf {F} :{\mathcal {X}}\to {\mathcal {Y}}} . The description of the properties of the random variables X {\displaystyle X} and of their images Y = F X {\displaystyle Y=\mathbf {F} X} is equivalent to the indication of the set A ⊆ X {\displaystyle {\mathcal {A}}\subseteq {\mathcal {X}}} from which X {\displaystyle X} must be taken and of the set B ⊆ Y {\displaystyle {\mathcal {B}}\subseteq {\mathcal {Y}}} into which its image must fall.
Unit element Examples Unit_(algebra) > Examples The multiplicative identity 1 and its additive inverse −1 are always units. More generally, any root of unity in a ring R is a unit: if rn = 1, then rn − 1 is a multiplicative inverse of r. In a nonzero ring, the element 0 is not a unit, so R× is not closed under addition. A nonzero ring R in which every nonzero element is a unit (that is, R× = R −{0}) is called a division ring (or a skew-field). A commutative division ring is called a field. For example, the unit group of the field of real numbers R is R − {0}.
Vibrio cholerae Pathogenicity Vibrio_cholerae > Pathogenicity In V. cholerae several TCS have been identified to be important in colonization, biofilm production and virulence. Quorum regulatory small RNAs (Qrr RNA) have been identified as targets of V. cholerae TCS. Here, the small RNA (sRNA) molecules bind to mRNA to block translation or induce degradation of inhibitors of expression of virulence or colonization genes.
Distributed representation Convolutional Distributed_representation > Feedforward > Convolutional They have shown superior results in both image and speech applications. They can be trained with standard backpropagation. CNNs are easier to train than other regular, deep, feed-forward neural networks and have many fewer parameters to estimate.Capsule Neural Networks (CapsNet) add structures called capsules to a CNN and reuse output from several capsules to form more stable (with respect to various perturbations) representations.Examples of applications in computer vision include DeepDream and robot navigation. They have wide applications in image and video recognition, recommender systems and natural language processing.
Averest Summary Averest Components: compiler to translate synchronous programs to transition systems, symbolic model checker, tool for hardware/software synthesis. These cover large parts of the design flow of reactive systems, from specifying to implementing. Though the tools are part of a common framework, they are mostly independent of each other, and can be used with 3rd-party tools.
Symbiodinium Life cycle Symbiodinium > Life cycle During asexual propagation (sometimes referred to as mitotic or vegetative growth), cells undergo a diel cycle of karyokinesis (chromosome/nuclear division) in darkness. The mother cell then divides (cytokinesis) soon after exposure to light and releases two motile cells. The initiation and duration of motility varies among species.
Low field NMR Readings Low_field_nuclear_magnetic_resonance > Readings ISSN 0009-2614. S2CID 95508271. Volegov, P.L.
Relativistic quantum theory Non-renormalizability Quantum_field > History > Non-renormalizability Given the tremendous success of QED, many theorists believed, in the few years after 1949, that QFT could soon provide an understanding of all microscopic phenomena, not only the interactions between photons, electrons, and positrons. Contrary to this optimism, QFT entered yet another period of depression that lasted for almost two decades. : 30 The first obstacle was the limited applicability of the renormalization procedure. In perturbative calculations in QED, all infinite quantities could be eliminated by redefining a small (finite) number of physical quantities (namely the mass and charge of the electron).
White Nose Syndrome Pathophysiology White-nose_syndrome > Research > Infection > Pathophysiology Hyperkalemia (elevated blood potassium) ensues because of an acidosis-induced extracellular shift of potassium. Dying, infected cells could also leak their (intracellular) potassium into the blood. The damaged wing epidermis might stimulate increased frequencies of arousal from torpor, which removes excess CO₂ and normalizes blood pH, at the expense of hydration and fat reserves. With worsening wing damage, the effects are exacerbated by water and electrolyte loss across the wound (hypotonic dehydration), which stimulates more frequent arousals in a positive feedback loop that ultimately leads to death.
Meaning (philosophy) Paul Grice Meaning_(philosophy) > Usage and meaning > Paul Grice His guiding maxim was called the cooperative principle, which claimed that the speaker and the listener will have mutual expectations of the kind of information that will be shared. The principle is broken down into four maxims: Quality (which demands truthfulness and honesty), Quantity (demand for just enough information as is required), Relation (relevance of things brought up), and Manner (lucidity). This principle, if and when followed, lets the speaker and listener figure out the meaning of certain implications by way of inference.
Disability and poverty Current initiatives Disability_and_poverty > Current initiatives This doctrine set stage for the UN Decade of the Disabled Person from 1983 to 1992, where, at its close, the General Assembly adopted the Standard Rules of the Equalization of Opportunities for Persons with Disabilities. The Standard Rules encourages states to remove social, cultural, economic, educational, and political barriers that bar individuals with disabilities from participating equally in society. Proponents claim that these movements on behalf of the UN helped facilitate more inclusive development policy and brought disability rights to the forefront.
Collision detection Collision detection in computer simulation Collision_detection > Collision detection in computer simulation Constraints avoid inertia and thus instability. Implementation of rest by means of a scene graph avoids drift. In other words, physical simulators usually function one of two ways: where the collision is detected a posteriori (after the collision occurs) or a priori (before the collision occurs). In addition to the a posteriori and a priori distinction, almost all modern collision detection algorithms are broken into a hierarchy of algorithms. Often the terms "discrete" and "continuous" are used rather than a posteriori and a priori.
Pulses per second Medium PRF Medium_pulse_repetition_frequency > Measurement > Medium PRF Medium PRF is used with Pulse-Doppler radar, which is required for look-down/shoot-down capability in military systems. Doppler radar return is generally not ambiguous until velocity exceeds the speed of sound. A technique called ambiguity resolution is required to identify true range and speed.
Afocal photography Afocal secondary lenses Afocal_photography > Afocal secondary lenses Besides combining a Keplerian telescope with a camera, there are also dedicated secondary lens afocal attachments that mount on the front of a camera lens to work in the role of a teleconverter, technically called teleside converters. These lenses are usually Galilean telescopes that alter the width of the entering beam of light without affecting the divergence of the beam, so they can change the effective focal length 1 to 3 times without increasing focal ratio. There are models that are 6x or 8x and even Russian made 12x to 14x Gregorian Maksutov designs that can be used as long lenses and microscopes. Like their Keplerian counterparts these can be universally adapted to most camera lenses with the proper type of adapter.
Logarithmic growth Summary Logarithmic_growth In more advanced mathematics, the partial sums of the harmonic series 1 + 1 2 + 1 3 + 1 4 + 1 5 + ⋯ {\displaystyle 1+{\frac {1}{2}}+{\frac {1}{3}}+{\frac {1}{4}}+{\frac {1}{5}}+\cdots } grow logarithmically. In the design of computer algorithms, logarithmic growth, and related variants, such as log-linear, or linearithmic, growth are very desirable indications of efficiency, and occur in the time complexity analysis of algorithms such as binary search.Logarithmic growth can lead to apparent paradoxes, as in the martingale roulette system, where the potential winnings before bankruptcy grow as the logarithm of the gambler's bankroll. It also plays a role in the St.
GNU make Rules GNU_make > Makefiles > Rules Because Make itself does not understand, recognize or distinguish different kinds of files, this opens up a possibility for human error. Each dependency line may be followed by a series of TAB indented command lines which define how to transform the components (usually source files) into the target (usually the "output"). If any of the prerequisites has a more recent modification time than the target, the command lines are run.
Functional MRI Preprocessing Functional_Magnetic_Resonance_Imaging > Analyzing the data > Preprocessing A plot with these periods on the x-axis and the heights on the y-axis is called a power spectrum, and this plot is created with the Fourier transform technique. Temporal filtering amounts to removing the periodic waves not of interest to us from the power spectrum, and then summing the waves back again, using the inverse Fourier transform to create a new timecourse for the voxel. A high-pass filter removes the lower frequencies, and the lowest frequency that can be identified with this technique is the reciprocal of twice the TR.
Covariance and contravariance (computer science) Interfaces Covariance_and_contravariance_(computer_science) > Generic types > Declaration-site variance annotations > Interfaces In C#, each type parameter of a generic interface can be marked covariant (out), contravariant (in), or invariant (no annotation). For example, we can define an interface IEnumerator of read-only iterators, and declare it to be covariant (out) in its type parameter. With this declaration, IEnumerator will be treated as covariant in its type parameter, e.g. IEnumerator is a subtype of IEnumerator . The type checker enforces that each method declaration in an interface only mentions the type parameters in a way consistent with the in/out annotations.
Protein-coding gene Human genetic disorders Human_genome_sequence_map > Human genetic disorders Molecularly characterized genetic disorders are those for which the underlying causal gene has been identified. Currently there are approximately 2,200 such disorders annotated in the OMIM database.Studies of genetic disorders are often performed by means of family-based studies. In some instances, population based approaches are employed, particularly in the case of so-called founder populations such as those in Finland, French-Canada, Utah, Sardinia, etc. Diagnosis and treatment of genetic disorders are usually performed by a geneticist-physician trained in clinical/medical genetics.
Iterative algorithm Introduction Iterative_algorithm > Linear systems > Stationary iterative methods > Introduction Stationary iterative methods solve a linear system with an operator approximating the original one; and based on a measurement of the error in the result (the residual), form a "correction equation" for which this process is repeated. While these methods are simple to derive, implement, and analyze, convergence is only guaranteed for a limited class of matrices.
Dimensionless material constant Atomic properties Material_property > Atomic properties Atomic mass: (applies to each element) the average mass of the atoms of an element, in daltons (Da), a.k.a. atomic mass units (amu). Atomic number: (applies to individual atoms or pure elements) the number of protons in each nucleus Relative atomic mass, a.k.a. atomic weight: (applies to individual isotopes or specific mixtures of isotopes of a given element) (no units) Standard atomic weight: the average relative atomic mass of a typical sample of the element (no units)
Linux Kernel Memory management Vmsplice()_local_root_exploit > Architecture and features > Memory management For example, pages reserved for DMA operations are in ZONE_DMA, pages that are not permanently mapped to virtual addresses are in ZONE_HIGHMEM (in x86_32 architecture this zone is for physical addresses above 896 MB, while x86_64 does not need it because x86_64 can permanently map physical pages that reside in higher addresses), and all that remains (with the exception of other less used classifications) is in ZONE_NORMAL. Small chunks of memory can be dynamically allocated via the family of kmalloc() APIs and freed with the appropriate variant of kfree(). vmalloc() and kvfree() are used for large virtually contiguous chunks.
Tracing garbage collection Weak collections Tracing_garbage_collection > Weak collections Data structures can also be devised which have weak tracking features. For instance, weak hash tables are useful. Like a regular hash table, a weak hash table maintains an association between pairs of objects, where each pair is understood to be a key and value. However, the hash table does not actually maintain a strong reference on these objects.
Wallerian degeneration Clearance in PNS Wallerian_degeneration > Myelin clearance > Clearance in PNS Schwann cells continue to clear up the myelin debris by degrading their own myelin, phagocytose extracellular myelin and attract macrophages to myelin debris for further phagocytosis. However, the macrophages are not attracted to the region for the first few days; hence the Schwann cells take the major role in myelin cleaning until then. Schwann cells have been observed to recruit macrophages by release of cytokines and chemokines after sensing of axonal injury.
Acid dissociation constant Strong acids and bases Acid_dissociation_constant > Strong acids and bases An acid is classified as "strong" when the concentration of its undissociated species is too low to be measured. Any aqueous acid with a pKa value of less than 0 is almost completely deprotonated and is considered a strong acid. All such acids transfer their protons to water and form the solvent cation species (H3O+ in aqueous solution) so that they all have essentially the same acidity, a phenomenon known as solvent leveling. They are said to be fully dissociated in aqueous solution because the amount of undissociated acid, in equilibrium with the dissociation products, is below the detection limit.
Communication in small groups Group decisions Communication_in_small_groups > Social influence in groups > Group decisions Reaching decisions by minority decision calls for a subcommittee getting together and reaching decisions without the whole groupe being involved. A final method is by authority rule. In this method, the group leader listens to individual group member's ideas, and has final say on a decision.
Underlying instrument Glossary Derivative_contract > Glossary Exchange-traded derivative contracts: Standardized derivative contracts (e.g., futures contracts and options) that are transacted on an organized futures exchange. Gross negative fair value: The sum of the fair values of contracts where the bank owes money to its counter-parties, without taking into account netting. This represents the maximum losses the bank's counter-parties would incur if the bank defaults and there is no netting of contracts, and no bank collateral was held by the counter-parties.
Delta-v Delta-v budgets Delta_V > Delta-v budgets For examples of calculating delta-v, see Hohmann transfer orbit, gravitational slingshot, and Interplanetary Transport Network. It is also notable that large thrust can reduce gravity drag. Delta-v is also required to keep satellites in orbit and is expended in propulsive orbital stationkeeping maneuvers. Since the propellant load on most satellites cannot be replenished, the amount of propellant initially loaded on a satellite may well determine its useful lifetime.
Glossary of linear algebra R Glossary_of_linear_algebra > R Row vector A matrix with only one row.
Photon Correlation Spectroscopy Introduction Photon_Correlation_Spectroscopy > Data analysis > Introduction In most cases, samples are polydisperse. Thus, the autocorrelation function is a sum of the exponential decays corresponding to each of the species in the population. g 1 ( q ; τ ) = ∑ i = 1 n G i ( Γ i ) exp ⁡ ( − Γ i τ ) = ∫ G ( Γ ) exp ⁡ ( − Γ τ ) d Γ .
Free list Summary Free_list A free list (or freelist) is a data structure used in a scheme for dynamic memory allocation. It operates by connecting unallocated regions of memory together in a linked list, using the first word of each unallocated region as a pointer to the next. It is most suitable for allocating from a memory pool, where all objects have the same size. Free lists make the allocation and deallocation operations very simple.
Power distance Effects on employee behavior Power_distance > Applications and effects > The workplace > Effects on employee behavior In business, power distance can be defined as the acceptance (by employees) of the relationship between the highest and lowest ranked members in an organization. Studies have suggested that employees in low power distance workplaces directly impact the distribution of office power. This could be due in part to the employees possessing more power (and therefore, more freedom to make changes) than in a high-power distance setting. In addition, the opposite has been suggested for employees in high power distance environments, with superiors not varying much in their position.
Von Mises yield criterion Physical interpretation of the von Mises yield criterion Von_Mises_criterion > Physical interpretation of the von Mises yield criterion thus we have τ oct = 2 3 σ y {\displaystyle \tau _{\text{oct}}={\frac {\sqrt {2}}{3}}\sigma _{\text{y}}\,\!} Strain energy density consists of two components - volumetric or dialational and distortional. Volumetric component is responsible for change in volume without any change in shape. Distortional component is responsible for shear deformation or change in shape.
Software remastering Introduction Software_remastering > Introduction Software remastering creates an application by rebuilding its code base from the software objects on an existing master repository. If the "mastering" process assembles a distribution for the release of a version, the remaster process does the same but with subtraction, modification, or addition to the master repository. Similarly a modified makefile orchestrates a computerized version of an application.
GRADELA Summary GRADELA GRADELA is a simple gradient elasticity model involving one internal length in addition to the two Lamé parameters. It allows eliminating elastic singularities and discontinuities and to interpret elastic size effects. This model has been suggested by Elias C. Aifantis. The main advantage of GRADELA over Mindlin's elasticity models (which contains five extra constants) is the fact that solutions of boundary value problems can be found in terms of corresponding solutions of classical elasticity by operator splitting method. In 1992-1993 it has been suggested by Elias C. Aifantis a generalization of the linear elastic constitutive relations by the gradient modification that contains the Laplacian in the form where l s {\displaystyle l_{s}} is the scale parameter.
Holomorphic function Definition Holomorphic_map > Definition In particular, the limit is taken as the complex number z tends to z0, and this means that the same value is obtained for any sequence of complex values for z that tends to z0. If the limit exists, f is said to be complex differentiable at z0. This concept of complex differentiability shares several properties with real differentiability: it is linear and obeys the product rule, quotient rule, and chain rule.A function is holomorphic on an open set U if it is complex differentiable at every point of U. A function f is holomorphic at a point z0 if it is holomorphic on some neighbourhood of z0.
Causality (book) Reviews Causality_(book) > Reviews Pearl succeeds in bringing together in a general nonparametric framework the counterfactual tradition of causal analysis with the variants of structural equation modeling worth keeping. The graph theory that he uses to accomplish this fusion is often elegant. Thus, Causality is a major statement, which all who claim to know what causality is must read. The book gave Pearl the 2001 Lakatos Award in Philosophy of Science.
Fission barrier Shell corrections Fission_barrier > Shell corrections This combination of macroscopic liquid drop and microscopic shell effects predicts that for nuclei in the U-Pu region, a double-humped fission barrier with equal barrier heights and a deep secondary minimum will occur. For heavier nuclei, like californium, the first barrier is predicted to be much larger than the second barrier and passage over the first barrier is rate determining. In general, there is ample experimental and theoretical evidence that the lowest energy path in the fission process corresponds to having the nucleus, initially in an axially symmetric and mass (reflection) symmetric shape pass over the first maximum in the fission barrier with an axially asymmetric but mass symmetric shape and then to pass over the second maximum in the barrier with an axially symmetric but mass (reflection) asymmetric shape. Because of the complicated multidimensional character of the fission process, there are no simple formulas for the fission barrier heights. However, there are extensive tabulations of experimental characterizations of the fission barrier heights for various nuclei.
Galerkin method History Galerkin_methods > History The approach is usually credited to Boris Galerkin. The method was explained to the Western reader by Hencky and Duncan among others. Its convergence was studied by Mikhlin and Leipholz Its coincidence with Fourier method was illustrated by Elishakoff et al. Its equivalence to Ritz's method for conservative problems was shown by Singer. Gander and Wanner showed how Ritz and Galerkin methods led to the modern finite element method. One hundred years of method's development was discussed by Repin. Elishakoff, Kaplunov and Kaplunov show that the Galerkin’s method was not developed by Ritz, contrary to the Timoshenko’s statements.
Equivalence checking Equivalence checking and levels of abstraction Formal_equivalence_checking > Equivalence checking and levels of abstraction This is a more general problem. A system design flow requires comparison between a transaction level model (TLM), e.g., written in SystemC and its corresponding RTL specification. Such a check is becoming of increasing interest in a system-on-a-chip (SoC) design environment.
Acoustic sensor Definition Acoustic_sensor > Definition The five basic steps are found equally well whether we are talking about an earthquake, a submarine using sonar to locate its foe, or a band playing in a rock concert. The central stage in the acoustical process is wave propagation.
Hairy cell leukemia Second-line therapy Hairy_cell_leukemia > Treatment > Second-line therapy Common criteria for treatment success include: Normalization of hemoglobin levels (above 12.0 g/dL), A normal or somewhat low platelet count (above 100 K/µL), and A normal or somewhat low absolute neutrophil count (above 1.5 K/µL).If it is well tolerated, patients usually take the hormone for 12 to 18 months. An attempt may be made then to end the treatment, but most patients discover that they need to continue taking the drug for it to be successful. These patients often continue taking this drug indefinitely, until either the disease becomes resistant to this hormone, or the body produces an immune system response that limits the drug's ability to function.
Quantitative psychology Statistical techniques Quantitative_psychology > History > Statistical techniques Statistical methods are the quantitative tools most used by psychologists. Pearson introduced the correlation coefficient and the chi-squared test. The 1900–1920 period saw the t-test (Student, 1908), the ANOVA (Fisher, 1925) and a non-parametric correlation coefficient (Spearman, 1904). A large number of tests were developed in the latter half of the 20th century (e.g., all the multivariate tests).
World lines Usage in physics World_lines > Usage in physics An event is then represented by a point in a Minkowski diagram, which is a plane usually plotted with the time coordinate, say t {\displaystyle t} , vertically, and the space coordinate, say x {\displaystyle x} , horizontally. As expressed by F.R. Harvey A curve M in is called a worldline of a particle if its tangent is future timelike at each point.
Resistojet rocket Physical Principles Resistojet_rocket > Physical Principles Resistojets can be considered an evolution of traditional cold gas thrusters, which are the simplest form of rocket engine available. Their fuel tank holds the propellant, which is then led into the nozzle where it decompresses, propelling the craft forward. In a resistojet, a resistor is used to heat the fluid before it enters the nozzle, making it expand more forcefully, resulting in higher specific impulse.
Atomic units Bohr model in atomic units Atomic_units_system > Bohr model in atomic units Atomic units are chosen to reflect the properties of electrons in atoms, which is particularly clear in the classical Bohr model of the hydrogen atom for the bound electron in its ground state: Mass = 1 a.u. of mass Orbital radius = 1 a.u. of length Orbital velocity = 1 a.u. of velocity Orbital period = 2π a.u.
HTTP location Relative URL absolute path example HTTP_location > Examples > Relative URL absolute path example Relative URLs are URLs that do not include a scheme or a host. In order to be understood they must be combined with the URL of the original request. A client request for https://www.example.com/blog/all: may get a server response with a path that is absolute because it starts with a slash: The URL of the location is expanded by the client to https://www.example.com/articles/.
Magnetic Sail Magnetic field interaction with charged particles Magnetic_sails > Physical principles > Magnetic field interaction with charged particles An ion or electron with charge q in a plasma moving at velocity v in a magnetic field B and electric field E is treated as an idealized point charge in the Lorentz force F = q E + q v × B {\displaystyle \mathbf {F} =q\,\mathbf {E} +q\,\mathbf {v} \times \mathbf {B} } . This means that the force on an ion or electron is proportional to the product of their charge q and velocity component v {\displaystyle v} perpendicular to the magnetic field B. A magnetic sail design introduces a magnetic field into a plasma flow which under certain conditions deflects the electrons and ions from their original trajectory with the particle's momentum transferred to the sail and hence the spacecraft thereby creating thrust. An electric sail uses an electric field E that under certain conditions interact with charged particles to create thrust.
Mediation analysis Approaches to mediation Intervening_variable > Approaches to mediation While the concept of mediation as defined within psychology is theoretically appealing, the methods used to study mediation empirically have been challenged by statisticians and epidemiologists and interpreted formally. Experimental-causal-chain design An experimental-causal-chain design is used when the proposed mediator is experimentally manipulated. Such a design implies that one manipulates some controlled third variable that they have reason to believe could be the underlying mechanism of a given relationship.
Spiral of silence theory Isolating the factors that remove isolation Spiral_of_silence_theory > Internet > Isolating the factors that remove isolation The concept of isolation has a variety of definitions, dependent upon the circumstances it is investigated in. In one instance the problem of isolation has been defined as social withdrawal, defined as low relative frequencies of peer interaction. Other researchers have defined isolation as low levels of peer acceptance or high levels of peer rejection. Research that considers isolation with regard to the Internet either focuses on how the Internet makes individuals more isolated from society by cutting off their contact from live human beings or how the Internet decreases social isolation of people by allowing them to expand their social networks and giving them more means to stay in touch with friends and family.
Microcontroller unit Summary Microprocessor_control In modern terminology, a microcontroller is similar to, but less sophisticated than, a system on a chip (SoC). An SoC may include a microcontroller as one of its components, but usually integrates it with advanced peripherals like a graphics processing unit (GPU), a Wi-Fi module, or one or more coprocessors.
Message Passing Interface Functionality Message_Passing_Interface > Functionality MPI library functions include, but are not limited to, point-to-point rendezvous-type send/receive operations, choosing between a Cartesian or graph-like logical process topology, exchanging data between process pairs (send/receive operations), combining partial results of computations (gather and reduce operations), synchronizing nodes (barrier operation) as well as obtaining network-related information such as the number of processes in the computing session, current processor identity that a process is mapped to, neighboring processes accessible in a logical topology, and so on. Point-to-point operations come in synchronous, asynchronous, buffered, and ready forms, to allow both relatively stronger and weaker semantics for the synchronization aspects of a rendezvous-send. Many outstanding operations are possible in asynchronous mode, in most implementations.
Glossary of gene expression terms A Glossary_of_genetics_(0–L) > A affected relative pair Any pair of organisms which are related genetically and both affected by the same trait. For example, two cousins who both have blue eyes are an affected relative pair since they are both affected by the allele that codes for blue eyes. allele One of multiple alternative versions of an individual gene, each of which is a viable DNA sequence occupying a given position, or locus, on a chromosome.
Herschel–Bulkley fluid Summary Herschel–Bulkley_fluid The Herschel–Bulkley fluid is a generalized model of a non-Newtonian fluid, in which the strain experienced by the fluid is related to the stress in a complicated, non-linear way. Three parameters characterize this relationship: the consistency k, the flow index n, and the yield shear stress τ 0 {\displaystyle \tau _{0}} . The consistency is a simple constant of proportionality, while the flow index measures the degree to which the fluid is shear-thinning or shear-thickening.
Fission product yield Mass vs. yield curve Fission_product_yield > Mass vs. yield curve If a graph of the mass or mole yield of fission products against the atomic number of the fragments is drawn then it has two peaks, one in the area zirconium through to palladium and one at xenon through to neodymium. This is because the fission event causes the nucleus to split in an asymmetric manner, as nuclei closer to magic numbers are more stable.Yield vs. Z - This is a typical distribution for the fission of uranium. Note that in the calculations used to make this graph the activation of fission products was ignored and the fission was assumed to occur in a single moment rather than a length of time. In this bar chart results are shown for different cooling times (time after fission).
Maxwell–Stefan diffusion Summary Maxwell–Stefan_diffusion The molecular friction between two components is proportional to their difference in speed and their mole fractions. In the simplest case, the gradient of chemical potential is the driving force of diffusion. For complex systems, such as electrolytic solutions, and other drivers, such as a pressure gradient, the equation must be expanded to include additional terms for interactions.
Generalized anxiety disorder Pregabalin and gabapentin Generalized_anxiety_disorder > Treatment > Pharmacotherapy > Pregabalin and gabapentin The anxiolytic effects of pregabalin appear to persist for at least six months continuous use, suggesting tolerance is less of a concern; this gives pregabalin an advantage over certain anxiolytic medications such as benzodiazepines.Gabapentin (Neurontin), a closely related medication to pregabalin with the same mechanism of action, has also demonstrated effectiveness in the treatment of GAD, though unlike pregabalin, it has not been approved specifically for this indication. Nonetheless, it is likely to be of similar usefulness in the management of this condition, and by virtue of being off-patent, it has the advantage of being significantly less expensive in comparison. In accordance, gabapentin is frequently prescribed off-label to treat GAD.
Industrial catalysts Low temperature shift (LTS) catalyst Industrial_catalysts > Water gas shift reaction > Low temperature shift (LTS) catalyst The first mechanism that was proposed for the LTS reaction was a redox mechanism, but later evidence showed that the reaction can proceed via associated intermediates. The different intermediates that is suggested are: HOCO, HCO and HCOO.
Base (chemical) Summary Chemical_base The Lewis theory is more general than the Brønsted model because the Lewis acid is not necessarily a proton, but can be another molecule (or ion) with a vacant low-lying orbital which can accept a pair of electrons. One notable example is boron trifluoride (BF3). Some other definitions of both bases and acids have been proposed in the past, but are not commonly used today.
The Iron Bridge Influence on bridge design The_Iron_Bridge > Influence on bridge design This was followed by a complete bridge of five ribs and 210 feet (64 m) span which he had erected in a field in Paddington, but without buttresses it was merely for display and was dismantled after a year. In 1793–96, the Wearmouth Bridge was built with a span of 235 feet (72 m), constructed from cast iron in the form of cast voussoirs, somewhat like the voussoirs of a masonry bridge. The bridge used some of the iron from Paine's bridge, which had been returned to the foundry in Rotherham.
Taylor's Theorem Statement of the theorem Quadratic_approximation > Taylor's theorem in one real variable > Statement of the theorem The precise statement of the most basic version of Taylor's theorem is as follows: The polynomial appearing in Taylor's theorem is the k {\textstyle {\boldsymbol {k}}} -th order Taylor polynomial of the function f at the point a. The Taylor polynomial is the unique "asymptotic best fit" polynomial in the sense that if there exists a function hk: R → R and a k {\textstyle k} -th order polynomial p such that then p = Pk. Taylor's theorem describes the asymptotic behavior of the remainder term which is the approximation error when approximating f with its Taylor polynomial. Using the little-o notation, the statement in Taylor's theorem reads as
Fraunhofer diffraction (mathematics) Solution using Fourier transform Fraunhofer_diffraction_equation > Slits > Two slits > Solution using Fourier transform The aperture can be represented by the function: where δ is the delta function. We have and giving This is the same expression as that derived above by integration.
Alan G. Thomas (scientist) Summary Alan_G._Thomas_(scientist) He demonstrated that Griffith's strain energy release rate provided a useful way to characterize the conditions at a crack tip, a problem that previously had been thought intractable due to the finite straining and nonlinearly elastic stress-strain behavior of rubber. Thomas has been recognised with many prizes and medals.

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