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Eka-actinium Predicted chemistry Unbiunium > Predicted chemistry Because of the lack of radial nodes in the 5g orbitals, analogous to the 4f but not the 5f orbitals, the position of unbiunium in the periodic table is expected to be more akin to that of lanthanum than that of actinium among its congeners, and Pekka Pyykkö proposed to rename the superactinides as "superlanthanides" for that reason. The lack of radial nodes in the 4f orbitals contribute to their core-like behavior in the lanthanide series, unlike the more valence-like 5f orbitals in the actinides; however, the relativistic expansion and destabilization of the 5g orbitals should partially compensate for their lack of radial nodes and hence smaller extent.Unbiunium is expected to fill the 8p1/2 orbital due to its relativistic stabilization, with a configuration of 8s2 8p1. Nevertheless, the 7d1 8s2 configuration, which would be analogous to lanthanum and actinium, is expected to be a low-lying excited state at only 0.412 eV, and the expected 5g1 8s2 configuration from the Madelung rule should be at 2.48 eV.
Polymer characterization Morphology Polymer_characterization > Morphology Polymer morphology is a microscale property that is largely dictated by the amorphous or crystalline portions of the polymer chains and their influence on each other. Microscopy techniques are especially useful in determining these microscale properties, as the domains created by the polymer morphology are large enough to be viewed using modern microscopy instruments. Some of the most common microscopy techniques used are X-ray diffraction, Transmission Electron Microscopy, Scanning Transmission Electron Microscopy, Scanning Electron Microscopy, and Atomic Force Microscopy. Polymer morphology on a mesoscale (nanometers to micrometers) is particularly important for the mechanical properties of many materials.
Fourier transformation Time scaling Fourier_transformation > Properties of the Fourier transform > Basic properties > Time scaling For a non-zero real number a, if h(x) = f(ax), then The case a = −1 leads to the time-reversal property, which states: if h(x) = f(−x), then ĥ(ξ) = f̂(−ξ).
Floating car data Summary Floating_car_data Floating car data (FCD) in traffic engineering and management is typically timestamped geo-localization and speed data directly collected by moving vehicles, in contrast to traditional traffic data collected at a fixed location by a stationary device or observer. In a physical interpretation context, FCD provides a Lagrangian description of the vehicle movements whereas stationary devices provide an Eulerian description. The participating vehicle acts itself consequently as a moving sensor using an onboard GPS receiver or cellular phone. The most common and widespread use of FCD is to determine the traffic speed on the road network. Based on these data, traffic congestion can be identified, travel times can be calculated, and traffic reports can be rapidly generated. In contrast to stationary devices such as traffic cameras, number plate recognition systems, and induction loops embedded in the roadway, no additional hardware on the road network is necessary.
Standard-Model Extension Spontaneous Lorentz symmetry breaking Standard-Model_Extension > Spontaneous Lorentz symmetry breaking Formal studies of the possible causes of the breakdown of Lorentz symmetry include investigations of the fate of the expected Nambu–Goldstone modes. Goldstone's theorem implies that the spontaneous breaking must be accompanied by massless bosons. These modes might be identified with the photon, the graviton, spin-dependent interactions, and spin-independent interactions.
Print job Components Print_queue > Components Status: We can this in three parts: Spooling: It represents the message that the printing application is still working. Printing: It represents the message that spool file is being read by the print processor Printed: It represents the message that the job has been fully written to the port.Data Type: It Identifies the format of the data in the spool file like EMF, RAW. Other configuration: Name, set of named properties, etc
Immutable class JavaScript Immutable_object > Language-specific details > JavaScript In JavaScript, all primitive types (Undefined, Null, Boolean, Number, BigInt, String, Symbol) are immutable, but custom objects are generally mutable. To simulate immutability in an object, one may define properties as read-only (writable: false). However, the approach above still lets new properties be added. Alternatively, one may use Object.freeze to make existing objects immutable.
Infinite-dimensional optimization Summary Infinite-dimensional_optimization In certain optimization problems the unknown optimal solution might not be a number or a vector, but rather a continuous quantity, for example a function or the shape of a body. Such a problem is an infinite-dimensional optimization problem, because, a continuous quantity cannot be determined by a finite number of certain degrees of freedom.
Outline of the human brain Isolating the brain from other structures Outline_of_the_human_brain > Structure of the human brain > Visible anatomy > Isolating the brain from other structures A single neuron typically has several inputs (dendrites) or sensors, a relatively long cord (axon) which typically branches many times, and has several outputs connecting to other neurons or muscle tissue. Neurons communicate information in a single direction from the input end to the output end. The spinal cord has three major functions:as a conduit for neurons communicating action information from brain outwards to motor muscles via motor neurons, as a conduit for neurons communicating sensory information, from the senses inwards to the brain (see also: Sensory neuron, Sensory receptor, Proprioception, and Category:Sensory receptors), as a center for coordinating certain automatic reflexes.
Lift force Horseshoe vortex system Dynamic_lift > Three-dimensional flow > Horseshoe vortex system Because the velocity is deduced from the vorticity in such theories, some authors describe the situation to imply that the vorticity is the cause of the velocity perturbations, using terms such as "the velocity induced by the vortex", for example. But attributing mechanical cause-and-effect between the vorticity and the velocity in this way is not consistent with the physics. The velocity perturbations in the flow around a wing are in fact produced by the pressure field.
Rock mass plasticity Yield surfaces for rocks Rock_mass_plasticity > Governing equations > Yield surfaces for rocks Design of mining and civil structures in rock typically involves a failure criterion that is cohesive-frictional. The failure criterion is used to determine whether a state of stress in the rock will lead to inelastic behavior, including brittle failure. For rocks under high hydrostatic stresses, brittle failure is preceded by plastic deformation and the failure criterion is used to determine the onset of plastic deformation. Typically, perfect plasticity is assumed beyond the yield point.
Modern searches for Lorentz violation Terrestrial Modern_searches_for_Lorentz_violation > Speed of light > Terrestrial This is related to the relative velocity between the Solar System and the rest frame of the cosmic microwave background radiation of ~368 km/s (see also Resonator Michelson–Morley experiments). In addition, the Standard-Model Extension (SME) can be used to obtain a larger number of isotropy coefficients in the photon sector. It uses the even- and odd-parity coefficients (3×3 matrices) κ ~ e − {\displaystyle {\tilde {\kappa }}_{e-}} , κ ~ o + {\displaystyle {\tilde {\kappa }}_{o+}} and κ ~ t r {\displaystyle {\tilde {\kappa }}_{tr}} .
Development communication Control through communication Development_communication > Policy > Development communication policy science > In the Information Age > Control through communication "Control is achieved through communication. Norbert Wiener, the father of cybernetics, equated communication with control and observed that it is negatively related to entropy, the tendency for all systems towards breakdown. This function or relationship is magnified in the Information Age." Therefore, in the Information Age, there seems to be a positive correlation between information and power, between communication and power.
Nestin (protein) Clinical significance Nestin_(protein) > Clinical significance These cells can differentiate into neurons, glia, keratinocytes, smooth muscle cells and melanocytes in vitro. Thus, hair follicle stem cells provide an effective, accessible, autologous source of stem cells for treatment of peripheral nerve injury.Nestin has recently received attention as a marker for detecting newly formed endothelial cells. Nestin is an angiogenesis marker of proliferating endothelial cells in colorectal cancer tissue.
Knower paradox Solutions Knower_paradox > Solutions Since, given the diagonal lemma, every sufficiently strong theory will have to accept something like (K), absurdity can only be avoided either by rejecting one of the two principles of knowledge (KF) and (PK) or by rejecting classical logic (which validates the reasoning from (KF) and (PK) to absurdity). The first kind of strategy subdivides in several alternatives. One approach takes its inspiration from the hierarchy of truth predicates familiar from Alfred Tarski's work on the Liar paradox and constructs a similar hierarchy of knowledge predicates. Another approach upholds a single knowledge predicate but takes the paradox to call into doubt either the unrestricted validity of (PK) or at least knowledge of (KF).
Malignant neoplasm Chemotherapy Malignant_cancer > Management > Chemotherapy Chemotherapy is the treatment of cancer with one or more cytotoxic anti-neoplastic drugs (chemotherapeutic agents) as part of a standardized regimen. The term encompasses a variety of drugs, which are divided into broad categories such as alkylating agents and antimetabolites. Traditional chemotherapeutic agents act by killing cells that divide rapidly, a critical property of most cancer cells.
Cholestatic hepatitis Primary sclerosing cholangitis Cholestatic_hepatitis > Causes > Rare causes of cholestasis > Primary sclerosing cholangitis Further evidence for genetic predisposition include the identification of 23 non-HLA susceptibility loci and a higher disease risk among siblings, though environmental factors appear to play a much greater role in pathogenesis.Another theory postulates that increased intestinal permeability contributes to PSC. Tight junctions, which normally maintain the integrity of the intestinal epithelium, may become disrupted in inflammation. Leaky tight junctions could allow commensal bacteria and toxins to enter portal circulation and reach the liver, where they can trigger inflammation and fibrosis.The intestinal dysbiosis theory hypothesizes that yet unidentified environmental triggers (e.g., diet, medication, inflammation) reduce microbiota diversity and/or alter the population of specific species.
Symmetry in mathematics Galois theory Mathematical_symmetry > Symmetry in abstract algebra > Galois theory Given a polynomial, it may be that some of the roots are connected by various algebraic equations. For example, it may be that for two of the roots, say A and B, that A2 + 5B3 = 7. The central idea of Galois theory is to consider those permutations (or rearrangements) of the roots having the property that any algebraic equation satisfied by the roots is still satisfied after the roots have been permuted. An important proviso is that we restrict ourselves to algebraic equations whose coefficients are rational numbers. Thus, Galois theory studies the symmetries inherent in algebraic equations.
Transcription translation feedback loop Summary Transcription_translation_feedback_loop Transcription-translation feedback loop (TTFL) is a cellular model for explaining circadian rhythms in behavior and physiology. Widely conserved across species, the TTFL is auto-regulatory, in which transcription of clock genes is regulated by their own protein products.
Neuronal circuits Circuitry Neuronal_network > Circuitry This type of circuit is exemplified in the respiratory center of the brainstem, which responds to a number of inputs from different sources by giving out an appropriate breathing pattern.A reverberating circuit produces a repetitive output. In a signalling procedure from one neuron to another in a linear sequence, one of the neurons may send a signal back to initiating neuron. Each time that the first neuron fires, the other neuron further down the sequence fire again sending it back to the source.
The Entropy Law and the Economic Process The shortcomings of both neoclassical economics and of Marxism Nicholas_Georgescu-Roegen > Work > Magnum opus on The Entropy Law and the Economic Process > The shortcomings of both neoclassical economics and of Marxism Georgescu-Roegen outlines that both main streams of economic thought having dominated the world since the end of the 19th century – namely neoclassical economics and Marxism – share the shortcoming of not taking into account the importance of natural resources in man's economy. : 2 Hence, Georgescu-Roegen engages himself in an intellectual battle with two fronts.
Field of characteristic zero History Field_(mathematics) > History These gaps were filled by Niels Henrik Abel in 1824. Évariste Galois, in 1832, devised necessary and sufficient criteria for a polynomial equation to be algebraically solvable, thus establishing in effect what is known as Galois theory today. Both Abel and Galois worked with what is today called an algebraic number field, but conceived neither an explicit notion of a field, nor of a group.
Time-evolving block decimation Introduction Time-evolving_block_decimation > Introduction When the first quantum computer is plugged in and functioning, the perspectives for the field of computational physics will look rather promising, but until that day one has to restrict oneself to the mundane tools offered by classical computers. While experimental physicists are putting a lot of effort in trying to build the first quantum computer, theoretical physicists are searching, in the field of quantum information theory (QIT), for genuine quantum algorithms, appropriate for problems that would perform badly when trying to be solved on a classical computer, but pretty fast and successful on a quantum one. The search for such algorithms is still going, the best-known (and almost the only ones found) being the Shor's algorithm, for factoring large numbers, and Grover's search algorithm.
Unbiased estimation of standard deviation Other distributions Unbiased_estimation_of_standard_deviation > Bias correction > Other distributions In cases where statistically independent data are modelled by a parametric family of distributions other than the normal distribution, the population standard deviation will, if it exists, be a function of the parameters of the model. One general approach to estimation would be maximum likelihood. Alternatively, it may be possible to use the Rao–Blackwell theorem as a route to finding a good estimate of the standard deviation. In neither case would the estimates obtained usually be unbiased.
Structural hazard Background Structural_hazard > Background Instructions in a pipelined processor are performed in several stages, so that at any given time several instructions are being processed in the various stages of the pipeline, such as fetch and execute. There are many different instruction pipeline microarchitectures, and instructions may be executed out-of-order. A hazard occurs when two or more of these simultaneous (possibly out of order) instructions conflict.
X boson Details X_and_Y_bosons > Details In these reactions, neither the lepton number (L) nor the baryon number (B) is separately conserved, but the combination B − L is. Different branching ratios between the X boson and its antiparticle (as is the case with the K-meson) would explain baryogenesis. For instance, if an X+ / X− pair is created out of energy, and they follow the two branches described above: X+ → uL + uR , X− → dL + e−R ;re-grouping the result ( u + u + d ) + e− = p + e− shows it to be a hydrogen atom.
Acute coronary syndrome Treatment Acute_coronary_syndromes > Treatment People with presumed ACS are typically treated with aspirin, clopidogrel or ticagrelor, nitroglycerin, and if the chest discomfort persists morphine. Other analgesics such as nitrous oxide are of unknown benefit. Angiography is recommended in those who have either new ST elevation or a new left or right bundle branch block on their ECG. Unless the person has low oxygen levels additional oxygen does not appear to be useful.
Human herpesvirus 6 Diagnosis Human_herpesvirus-6 > Diagnosis The diagnosis of HHV-6 infection is performed by both serologic and direct methods. The most prominent technique is the quantification of viral DNA in blood, other body fluids, and organs by means of real-time PCR.
RNase P In eukaryotes RNase_P > In eukaryotes RNase P from eukaryotes was only recently demonstrated to be a ribozyme. Accordingly, the numerous protein subunits of eucaryal RNase P have a minor contribution to tRNA processing per se, while they seem to be essential for the function of RNase P and RNase MRP in other biological settings, such as gene transcription and the cell cycle. Despite the bacterial origins of mitochondria and chloroplasts, plastids from higher animals and plants do not appear to contain an RNA-based RNase P. It has been shown that human mitochondrial RNase P is a protein and does not contain RNA. Spinach chloroplast RNase P has also been shown to function without an RNA subunit.
Timeline of special relativity and the speed of light Before the 19th century Timeline_of_special_relativity_and_the_speed_of_light > Before the 19th century 1727 – James Bradley correctly identifies the peculiar behaviour of γ Draconis as stellar aberration. Bradley uses this fact to estimate the speed of light in air or vacuum, and his result is more accurate than Huygens’s: about 3.0×108 m/s in modern units. For the first time, the measurement is correct to the first two significant figures.
IR spectrum Comparing to a reference Infrared_spectrophotometry > Practical IR spectroscopy > Comparing to a reference The simplest reference measurement is to simply remove the sample (replacing it by air). However, sometimes a different reference is more useful. For example, if the sample is a dilute solute dissolved in water in a beaker, then a good reference measurement might be to measure pure water in the same beaker.
Inorganic phosphate Equilibria in solution Phosphate_group > Chemical properties > Equilibria in solution Around pH 9.8 (mid-way between the second and third pKa values) the monohydrogen phosphate ion, 2−, is the only species present. At pH 13 or higher, the acid is completely dissociated as the phosphate ion, (PO4)3−. This means that salts of the mono- and di-phosphate ions can be selectively crystallised from aqueous solution by setting the pH value to either 4.7 or 9.8.
Eurytherm Thermal coping mechanisms Eurytherm > Thermal coping mechanisms The first is shivering, in which a warm-blooded creature produces involuntary contraction of skeletal muscle in order to produce heat. In addition, shivering also signals the body to produce irisin, a hormone that has been shown to convert white fat to brown fat, which is used in non-shivering thermogenesis, the second type of human thermogensis. Non-shivering thermogenesis occurs in the brown fat, which contains the uncoupling protein thermogenin.
Network analyzer (electrical) Noise figure measurements Vector_network_analyzer > Noise figure measurements The three major manufacturers of VNAs, Keysight, Anritsu, and Rohde & Schwarz, all produce models which permit the use of noise figure measurements. The vector error correction permits higher accuracy than is possible with other forms of commercial noise figure meters.
G force Summary G_force More transient acceleration, accompanied with significant jerk, is called shock. When the g-force is produced by the surface of one object being pushed by the surface of another object, the reaction force to this push produces an equal and opposite force for every unit of each object's mass. The types of forces involved are transmitted through objects by interior mechanical stresses.
Physical model "Model" in specific contexts Physical_models > "Model" in specific contexts As a noun, "model" has specific meanings in certain fields, derived from its original meaning of "structural design": Model (art), a person posing for an artist, e.g. a 15th-century criminal representing the biblical Judas in Leonardo da Vinci's painting The Last Supper Model (person), a person who serves as a template for others to copy, as in a role model, often in the context of advertising commercial products; e.g. the first fashion model Marie Vernet Worth in 1853, wife of designer Charles Frederick Worth.Model (product), a particular design of a product as displayed in a catalogue or show room (e.g. Ford Model T, an early car model) Model (organism) a non-human species that is studied to understand biological phenomena in other organisms, e.g. a guinea pig starved of vitamin C to study scurvy, an experiment that would be immoral to conduct on a person Model (mimicry), a species that is mimicked by another species Model (logic), a structure (a set of items, such as natural numbers 1, 2, 3,...) along with mathematical operations (such as addition and multiplication) and relations (such as < {\displaystyle <} ) that satisfies a given system of axioms (basic truisms)
Pythagorean prime Values and density Pythagorean_prime > Values and density The first few Pythagorean primes are By Dirichlet's theorem on arithmetic progressions, this sequence is infinite. More strongly, for each n {\displaystyle n} , the numbers of Pythagorean and non-Pythagorean primes up to n {\displaystyle n} are approximately equal. However, the number of Pythagorean primes up to n {\displaystyle n} is frequently somewhat smaller than the number of non-Pythagorean primes; this phenomenon is known as Chebyshev's bias. For example, the only values of n {\displaystyle n} up to 600000 for which there are more Pythagorean than non-Pythagorean odd primes less than or equal to n are 26861 and 26862.
RAFOS float Of the importance of measuring ocean currents RAFOS_float > Introduction > Of the importance of measuring ocean currents In important scientific aspects, as the study of global warming, ocean currents are found to greatly affect the Earth's climate since they are the main heat transfer mechanism. They are the reason for heat flux between hot and cold regions, and in a larger sense drive almost every understood circulation. These currents also affect marine debris, and vice versa.
Highly irregular graph Applications of irregularity Highly_irregular_graph > Applications of irregularity Definitions of irregularity have been important in the study of network heterogeneity, which has implications in networks found across biology, ecology, technology, and economy. There have been several graph statistics that have been suggested, many of which are based on the number of vertices in a graph and their degrees. The characterization of highly irregular graphs has also been applied to the question of heterogeneity, yet all of these fail to shed enough light on real-world situations. Efforts continue to be made to find appropriate ways to quantify network heterogeneity. == References ==
Discrete category Summary Discrete_category In mathematics, in the field of category theory, a discrete category is a category whose only morphisms are the identity morphisms: homC(X, X) = {idX} for all objects X homC(X, Y) = ∅ for all objects X ≠ YSince by axioms, there is always the identity morphism between the same object, we can express the above as condition on the cardinality of the hom-set \| homC(X, Y) \| is 1 when X = Y and 0 when X is not equal to Y.Some authors prefer a weaker notion, where a discrete category merely needs to be equivalent to such a category.
Dynastic cycle The cycle Dynastic_cycle > The cycle The famine causes the population to rebel and a civil war ensues. The ruler loses the Mandate of Heaven.
Single-stranded DNA Transcription and translation Single-stranded_DNA > Biological functions > Transcription and translation A gene is a sequence of DNA that contains genetic information and can influence the phenotype of an organism. Within a gene, the sequence of bases along a DNA strand defines a messenger RNA sequence, which then defines one or more protein sequences. The relationship between the nucleotide sequences of genes and the amino-acid sequences of proteins is determined by the rules of translation, known collectively as the genetic code. The genetic code consists of three-letter 'words' called codons formed from a sequence of three nucleotides (e.g. ACT, CAG, TTT).
Serotonin toxicity Management Serotonin_Syndrome > Management Moderate cases should have all thermal and cardiorespiratory abnormalities corrected and can benefit from serotonin antagonists. The serotonin antagonist cyproheptadine is the recommended initial therapy, although there have been no controlled trials demonstrating its efficacy for SS. Despite the absence of controlled trials, there are a number of case reports detailing apparent improvement after people have been administered cyproheptadine.
Pore-C Background Pore-C > Background Although the DNA within eukaryotic cells is linear, it is also intricately folded and packaged to fit within each cell’s nucleus. Thus, specific parts of the genome may be closer in physical space than would otherwise appear to be based on DNA sequence alone. The 3D genome refers to how DNA is spatially organized within cells. The 3D structures found in the genome include active and inactive chromatin, chromatin loops, and topologically associated domains (TADs).
Alan Turing University and work on computability Alan_Turing > Early life and education > University and work on computability Later that year, Turing was elected a Fellow of King's College on the strength of his dissertation. However, and, unknown to Turing, this version of the theorem he proved in his paper, had already been proven, in 1922, by Jarl Waldemar Lindeberg. Despite this, the committee found Turing's methods original and so regarded the work worthy of consideration for the fellowship.
Function domain Examples Domain_of_a_function > Natural domain > Examples The function f {\displaystyle f} defined by f ( x ) = 1 x {\displaystyle f(x)={\frac {1}{x}}} cannot be evaluated at 0. Therefore the natural domain of f {\displaystyle f} is the set of real numbers excluding 0, which can be denoted by R ∖ { 0 } {\displaystyle \mathbb {R} \setminus \{0\}} or { x ∈ R: x ≠ 0 } {\displaystyle \{x\in \mathbb {R} :x\neq 0\}} . The piecewise function f {\displaystyle f} defined by f ( x ) = { 1 / x x ≠ 0 0 x = 0 , {\displaystyle f(x)={\begin{cases}1/x&x\not =0\\0&x=0\end{cases}},} has as its natural domain the set R {\displaystyle \mathbb {R} } of real numbers. The square root function f ( x ) = x {\displaystyle f(x)={\sqrt {x}}} has as its natural domain the set of non-negative real numbers, which can be denoted by R ≥ 0 {\displaystyle \mathbb {R} _{\geq 0}} , the interval [ 0 , ∞ ) {\displaystyle [0,\infty )} , or { x ∈ R: x ≥ 0 } {\displaystyle \{x\in \mathbb {R} :x\geq 0\}} . The tangent function, denoted tan {\displaystyle \tan } , has as its natural domain the set of all real numbers which are not of the form π 2 + k π {\displaystyle {\tfrac {\pi }{2}}+k\pi } for some integer k {\displaystyle k} , which can be written as R ∖ { π 2 + k π: k ∈ Z } {\displaystyle \mathbb {R} \setminus \{{\tfrac {\pi }{2}}+k\pi :k\in \mathbb {Z} \}} .
Avogadro constant Summary Avogadro_number The redefinition of the mole in 2019, as being the amount of substance containing exactly 6.02214076×1023 particles, meant that the mass of 1 mole of a substance is now exactly the product of the Avogadro number and the average mass of its particles. The dalton however is still defined as 1/12 of the mass of a 12C atom, which must be determined experimentally and is known only with finite accuracy. The prior experiments that aimed to determine the Avogadro constant are now re-interpreted as measurements of the value in grams of the dalton.
Iron bloom Process Iron_bloom > Process Overall, a typical ratio of total charcoal to ore added is in a roughly one-to-one ratio. Inside the furnace, carbon monoxide from the incomplete combustion of the charcoal reduces the iron oxides in the ore to metallic iron without melting the ore; this allows the bloomery to operate at lower temperatures than the melting temperature of the ore. As the desired product of a bloomery is iron that is easily forgeable, it requires a low carbon content.
Newtonian laws Momentum conservation and the third law Newton's_First_Law > History > Momentum conservation and the third law Johannes Kepler suggested that gravitational attractions were reciprocal — that, for example, the Moon pulls on the Earth while the Earth pulls on the Moon — but he did not argue that such pairs are equal and opposite. In his Principles of Philosophy (1644), Descartes introduced the idea that during a collision between bodies, a "quantity of motion" remains unchanged. Descartes defined this quantity somewhat imprecisely by adding up the products of the speed and "size" of each body, where "size" for him incorporated both volume and surface area. Moreover, Descartes thought of the universe as a plenum, that is, filled with matter, so all motion required a body to displace a medium as it moved.
Performance Enhancing Proxy Classification Performance_Enhancing_Proxy > Classification This is quite common in commercial PEP devices, which act as a black box, using more or less open protocols to communicate between them in the place of TCP. Symmetry: A PEP implementation may be symmetric or asymmetric. Symmetric PEPs use identical behavior in both directions; the actions taken by the PEP occur independent from which interface a packet is received. Asymmetric PEPs operate differently in each direction, which can cause, for example, only one link direction performance to be enhanced.
Generalized eigenvalue problem Eigendecomposition of a matrix Eigenvalue_decomposition > Eigendecomposition of a matrix One special case is that if A is a normal matrix, then by the spectral theorem, it's always possible to diagonalize A in an orthonormal basis {qi}. The decomposition can be derived from the fundamental property of eigenvectors: A v = λ v A Q = Q Λ A = Q Λ Q − 1 . {\displaystyle {\begin{aligned}\mathbf {A} \mathbf {v} &=\lambda \mathbf {v} \\\mathbf {A} \mathbf {Q} &=\mathbf {Q} \mathbf {\Lambda } \\\mathbf {A} &=\mathbf {Q} \mathbf {\Lambda } \mathbf {Q} ^{-1}.\end{aligned}}} The linearly independent eigenvectors qi with nonzero eigenvalues form a basis (not necessarily orthonormal) for all possible products Ax, for x ∈ Cn, which is the same as the image (or range) of the corresponding matrix transformation, and also the column space of the matrix A. The number of linearly independent eigenvectors qi with nonzero eigenvalues is equal to the rank of the matrix A, and also the dimension of the image (or range) of the corresponding matrix transformation, as well as its column space. The linearly independent eigenvectors qi with an eigenvalue of zero form a basis (which can be chosen to be orthonormal) for the null space (also known as the kernel) of the matrix transformation A.
NH₃ Amphotericity Ammonium_nitride > Properties > Amphotericity NH3 + HCl → ClThe salts produced by the action of ammonia on acids are known as the ammonium salts and all contain the ammonium ion (+).Although ammonia is well known as a weak base, it can also act as an extremely weak acid. It is a protic substance and is capable of formation of amides (which contain the NH−2 ion). For example, lithium dissolves in liquid ammonia to give a blue solution (solvated electron) of lithium amide: 2 Li + 2 NH3 → 2 LiNH2 + H2
Paxos algorithm Multi-Paxos when phase 1 can be skipped Paxos_algorithm > Multi-Paxos > Graphic representation of the flow of messages in the Multi-Paxos > Multi-Paxos when phase 1 can be skipped In this case, subsequent instances of the basic Paxos protocol (represented by I+1) use the same leader, so the phase 1 (of these subsequent instances of the basic Paxos protocol), which consist of the Prepare and Promise sub-phases, is skipped. Note that the Leader should be stable, i.e. it should not crash or change. Client Proposer Acceptor Learner \| \| \| \| \| \| \| --- Following Requests --- X-------->\| \| \| \| \| \| Request \| X--------->\|->\|->\| \| \| Accept! (N,I+1,W) \| \|<---------X--X--X------>\|->\| Accepted(N,I+1,W) \|<---------------------------------X--X Response \| \| \| \| \| \| \|
Storm Water Management Model Low-impact development components Storm_Water_Management_Model > Low-impact development components As such, these structures are designed to blend into neighborhoods and are viewed as an amenity. Dry ponds temporarily store water after a storm, but eventually empties out at a controlled rate to a downstream water body.
Direct Rendering Manager Kernel Mode Setting Graphics_Execution_Manager > Software architecture > Kernel Mode Setting The XFree86-VidModeExtension extension was introduced in XFree86 3.1.2 to let any X client request modeline (resolution) changes to the X Server. VidMode extension was later superseded by the more generic XRandR extension. However, this was not the only code doing mode-setting in a Linux system.
Adequality Scholarly controversy Adequality > Scholarly controversy Michael Sean Mahoney (1971) wrote:Fermat's Method of maxima and minima, which is clearly applicable to any polynomial P(x), originally rested on purely finitistic algebraic foundations. It assumed, counterfactually, the inequality of two equal roots in order to determine, by Viete's theory of equations, a relation between those roots and one of the coefficients of the polynomial, a relation that was fully general. This relation then led to an extreme-value solution when Fermat removed his counterfactual assumption and set the roots equal.
Glossary of engineering: M–Z R Virtual_leak > R Rheology is a branch of physics, and it is the science that deals with the deformation and flow of materials, both solids and liquids. Rigid bodyIn physics, a rigid body (also known as a rigid object ) is a solid body in which deformation is zero or so small it can be neglected. The distance between any two given points on a rigid body remains constant in time regardless of external forces or moments exerted on it.
Attractive (force) Static Attractive_(force) > Combining forces > Equilibrium > Static The situation produces zero net force and hence no acceleration.Pushing against an object that rests on a frictional surface can result in a situation where the object does not move because the applied force is opposed by static friction, generated between the object and the table surface. For a situation with no movement, the static friction force exactly balances the applied force resulting in no acceleration. The static friction increases or decreases in response to the applied force up to an upper limit determined by the characteristics of the contact between the surface and the object.A static equilibrium between two forces is the most usual way of measuring forces, using simple devices such as weighing scales and spring balances.
Infrastructure security Summary Infrastructure_security Infrastructure security is the security provided to protect infrastructure, especially critical infrastructure, such as airports, highways rail transport, hospitals, bridges, transport hubs, network communications, media, the electricity grid, dams, power plants, seaports, oil refineries, liquefied natural gas terminals and water systems. Infrastructure security seeks to limit vulnerability of these structures and systems to sabotage, terrorism, and contamination.Critical infrastructures naturally utilize information technology as this capability has become more and more available. As a result, they have become highly interconnected, and interdependent.
Early flying machines Learning to glide Early_flying_machines > Heavier than air > 19th century > Learning to glide By 1889, he had constructed a rotary engine driven by compressed air. Octave Chanute became convinced that multiple wing planes were more effective than a monoplane and introduced the "strut-wire" braced wing structure which, with its combination of rigidity and lightness, would in the form of the biplane come to dominate aircraft design for decades to come. Even balloon-jumping began to succeed. In 1905, Daniel Maloney was carried by balloon in a tandem-wing glider designed by John Montgomery to an altitude of 4,000 feet (1,200 m) before being released, gliding down and landing at a predetermined location as part of a large public demonstration of aerial flight at Santa Clara, California. However, after several successful flights, during an ascension in July 1905, a rope from the balloon struck the glider, and the glider suffered structural failure after release, resulting in Maloney's death.
Generative AI Code Generative_AI > Modalities > Code In addition to natural language text, large language models can be trained on programming language text, allowing them to generate source code for new computer programs. Examples include OpenAI Codex.
H3K4me1 Epigenetic implications H3K4me1 > Epigenetic implications These annotated states can be used as new ways to annotate a genome independently of the underlying genome sequence. This independence from the DNA sequence enforces the epigenetic nature of histone modifications. Chromatin states are also useful in identifying regulatory elements that have no defined sequence, such as enhancers. This additional level of annotation allows for a deeper understanding of cell specific gene regulation.
Optimizing compilers List of static code analyses Compiler_analysis > List of static code analyses Alias analysis Pointer analysis Shape analysis Escape analysis Array-access analysis Dependence analysis Control-flow analysis Data-flow analysis Use-define chain analysis Live-variable analysis Available expression analysis
Bituminous rocks Summary Bituminous_rocks Organic-rich sedimentary rocks are a specific type of sedimentary rock that contains significant amounts (>3%) of organic carbon. The most common types include coal, lignite, oil shale, or black shale. The organic material may be disseminated throughout the rock giving it a uniform dark color, and/or it may be present as discrete occurrences of tar, bitumen, asphalt, petroleum, coal or carbonaceous material.
Universal Indicator Summary Universal_Indicator The colours that indicate the pH of a solution, after adding a universal indicator, are The colors from yellow to red indicate an acidic solution, colours blue to violet indicate an alkaline solution and a green colour indicates that a solution is neutral. Wide-range pH test papers with distinct colours for each pH from 1 to 14 are also available. Colour matching charts are supplied with the specific test strips purchased.
Aluminium hydroxide Properties Aluminum_hydroxide > Properties Aluminium hydroxide is amphoteric. In acid, it acts as a Brønsted–Lowry base. It neutralizes the acid, yielding a salt: 3 HCl + Al(OH)3 → AlCl3 + 3 H2OIn bases, it acts as a Lewis acid by binding hydroxide ions: Al(OH)3 + OH− → −
Vasiliev equations Discrepancies between Vasiliev equations and Higher Spin Theories Vasiliev_equations > Discrepancies between Vasiliev equations and Higher Spin Theories General analysis of the Vasiliev equations at the second order showed that for any three fixed spins the interaction term is an infinite series in derivatives (similar to k {\displaystyle k} -sum above); all of the terms in the series contribute to the same AdS/CFT three-point function and the contribution is infinite. All the problems can be attributed to the assumptions used in the derivation of the Vasiliev equations: restrictions on the number of derivatives in the interaction vertices or, more generally, locality was not imposed, which is important for getting meaningful interaction vertices, see e.g. Noether Procedure. The problem how to impose locality and extract interaction vertices out of the equations is now under active investigation.As is briefly mentioned in Other dimensions, extensions, and generalisations there is an option to introduce infinitely many additional coupling constants that enter via phase factor θ ( x ) = θ 0 + θ 2 x 2 + .
Nuclear fusion–fission hybrid Engineering considerations Nuclear_fusion-fission_hybrid > Engineering considerations D-T fuel can be manufactured on-site using Deuterium derived from heavy water production and Tritium generated in the hybrid reactor itself. Nuclear spallation to generate additional neutrons can be used to enhance the fission output, with the caveat that this is a tradeoff between the number of neutrons (typically 20-30 neutrons per spallation event) against a reduction of the individual energy of each neutron. This is a consideration if the reactor is to use natural Thorium as a fuel. While high energy (0.17c) neutrons produced from fusion events are capable of directly causing fission in both Thorium and 238U, the lower energy neutrons produced by spallation generally cannot. This is a tradeoff that affects the mixture of fuels against the degree of spallation used in the design.
Systems approach Systems far from equilibrium System_thinking > Characteristics > Systems far from equilibrium Living systems are resilient, and are far from equilibrium. : Ch.3 Homeostasis is the analog to equilibrium, for a living system; the concept was described in 1849, and the term was coined in 1926. Resilient systems are self-organizing;: Ch.3 The scope of functional controls is hierarchical, in a resilient system. : Ch.3
Bridge abutment Summary Bridge_abutment An abutment is the substructure at the ends of a bridge span or dam supporting its superstructure. Single-span bridges have abutments at each end that provide vertical and lateral support for the span, as well as acting as retaining walls to resist lateral movement of the earthen fill of the bridge approach. Multi-span bridges require piers to support ends of spans unsupported by abutments.
Spectral method Summary Spectral_method When applying spectral methods to time-dependent PDEs, the solution is typically written as a sum of basis functions with time-dependent coefficients; substituting this in the PDE yields a system of ODEs in the coefficients which can be solved using any numerical method for ODEs. Eigenvalue problems for ODEs are similarly converted to matrix eigenvalue problems. Spectral methods were developed in a long series of papers by Steven Orszag starting in 1969 including, but not limited to, Fourier series methods for periodic geometry problems, polynomial spectral methods for finite and unbounded geometry problems, pseudospectral methods for highly nonlinear problems, and spectral iteration methods for fast solution of steady-state problems.
Internal combustion engine cooling Basic principles Engine_coolant_temperature_sensor > Basic principles Moving parts such as the pistons, and to a lesser extent the crankshaft and connecting rods, must rely on the lubrication oil as a coolant, or to a very limited amount of conduction into the block and thence the main coolant. High performance engines frequently have additional oil, beyond the amount needed for lubrication, sprayed upwards onto the bottom of the piston just for extra cooling. Air-cooled motorcycles often rely heavily on oil-cooling in addition to air-cooling of the cylinder barrels.
Lin–log graph Summary Semi-logarithmic_graph The logarithmic scale is usually labeled in base 10; occasionally in base 2: log ⁡ ( y ) = ( γ log ⁡ ( a ) ) x + log ⁡ ( λ ) . {\displaystyle \log(y)=(\gamma \log(a))x+\log(\lambda ).} A log–linear (sometimes log–lin) plot has the logarithmic scale on the y-axis, and a linear scale on the x-axis; a linear–log (sometimes lin–log) is the opposite.
Pythagorean tiling Summary Pythagorean_tiling A Pythagorean tiling or two squares tessellation is a tiling of a Euclidean plane by squares of two different sizes, in which each square touches four squares of the other size on its four sides. Many proofs of the Pythagorean theorem are based on it, explaining its name. It is commonly used as a pattern for floor tiles.
Drug interactions Underlying factors Drug_interactions > Underlying factors Hepatic or renal diseases: The blood concentrations of drugs that are metabolized in the liver and/or eliminated by the kidneys may be altered if either of these organs is not functioning correctly. If this is the case an increase in blood concentration is normally seen. Serious diseases that could worsen if the dose of the medicine is reduced.
Exception handling (programming) Termination and resumption semantics Exception_handling_(programming) > Termination and resumption semantics When an exception is thrown, the program searches back through the stack of function calls until an exception handler is found. Some languages call for unwinding the stack as this search progresses. That is, if function f, containing a handler H for exception E, calls function g, which in turn calls function h, and an exception E occurs in h, then functions h and g may be terminated, and H in f will handle E. This is said to be termination semantics. Alternately, the exception handling mechanisms may not unwind the stack on entry to an exception handler, giving the exception handler the option to restart the computation, resume or unwind.
Respiration in plant Efficiency of ATP production Aerobic_metabolism > Efficiency of ATP production The table below describes the reactions involved when one glucose molecule is fully oxidized into carbon dioxide. It is assumed that all the reduced coenzymes are oxidized by the electron transport chain and used for oxidative phosphorylation. Although there is a theoretical yield of 38 ATP molecules per glucose during cellular respiration, such conditions are generally not realized because of losses such as the cost of moving pyruvate (from glycolysis), phosphate, and ADP (substrates for ATP synthesis) into the mitochondria. All are actively transported using carriers that utilize the stored energy in the proton electrochemical gradient.
Sigma bonds Summary Sigma_electron As a practical consequence of this mixing of diatomic molecules, the wavefunctions s+s and pz+pz molecular orbitals become blended. The extent of this mixing (or hybridization or blending) depends on the relative energies of the MOs of like symmetry. For homodiatomics (homonuclear diatomic molecules), bonding σ orbitals have no nodal planes at which the wavefunction is zero, either between the bonded atoms or passing through the bonded atoms.
Fast inverse square root Motivation Fast_inverse_square_root > Motivation The inverse square root of a floating point number is used in digital signal processing to normalize a vector, scaling it to length 1 to produce a unit vector. For example, computer graphics programs use inverse square roots to compute angles of incidence and reflection for lighting and shading. 3D graphics programs must perform millions of these calculations every second to simulate lighting. When the code was developed in the early 1990s, most floating point processing power lagged the speed of integer processing.
Aether wind Einstein's views on the aether Aether_wind > End of aether > Einstein's views on the aether This concept was fully elaborated within general relativity, in which physical properties (which are partially determined by matter) are attributed to space, but no substance or state of motion can be attributed to that "aether" (by which he meant curved space-time).In another paper of 1924, named "Concerning the Aether", Einstein argued that Newton's absolute space, in which acceleration is absolute, is the "Aether of Mechanics". And within the electromagnetic theory of Maxwell and Lorentz one can speak of the "Aether of Electrodynamics", in which the aether possesses an absolute state of motion. As regards special relativity, also in this theory acceleration is absolute as in Newton's mechanics.
In vitro recombination Summary In_vitro_recombination Recombinant DNA (rDNA), or molecular cloning, is the process by which a single gene, or segment of DNA, is isolated and amplified. Recombinant DNA is also known as in vitro recombination. A cloning vector is a DNA molecule that carries foreign DNA into a host cell, where it replicates, producing many copies of itself along with the foreign DNA. There are many types of cloning vectors such as plasmids and phages. In order to carry out recombination between vector and the foreign DNA, it is necessary the vector and DNA to be cloned by digestion, ligase the foreign DNA into the vector with the enzyme DNA ligase. And DNA is inserted by introducing the DNA into bacteria cells by transformation.
Carbon nanotube field-effect transistor Summary Carbon_nanotube_field-effect_transistor A carbon nanotube field-effect transistor (CNTFET) is a field-effect transistor that utilizes a single carbon nanotube (CNT) or an array of carbon nanotubes as the channel material, instead of bulk silicon, as in the traditional MOSFET structure. There have been major developments since CNTFETs were first demonstrated in 1998.
Internet performance Infrastructure Public_Internet > Infrastructure The communications infrastructure of the Internet consists of its hardware components and a system of software layers that control various aspects of the architecture. As with any computer network, the Internet physically consists of routers, media (such as cabling and radio links), repeaters, modems etc. However, as an example of internetworking, many of the network nodes are not necessarily Internet equipment per se, the internet packets are carried by other full-fledged networking protocols with the Internet acting as a homogeneous networking standard, running across heterogeneous hardware, with the packets guided to their destinations by IP routers.
Pulse-Doppler radar Benefits Pulse-Doppler_radar > Principle > Benefits Pulse-Doppler radar corrects this as follows. Allows the radar antenna to be pointed directly at the ground without overwhelming the computer and without reducing sensitivity. Fills in the vulnerability region associated with pulse-amplitude time-domain radar for small object detection near terrain and weather.
Memoization Etymology Memoization > Etymology The term "memoization" was coined by Donald Michie in 1968 and is derived from the Latin word "memorandum" ("to be remembered"), usually truncated as "memo" in American English, and thus carries the meaning of "turning a function into something to be remembered". While "memoization" might be confused with "memorization" (because they are etymological cognates), "memoization" has a specialized meaning in computing.
Integrity Management Plan Summary Integrity_Management_Plan Particularly post the Deepwater Horizon oil spill, the role of asset integrity has never been more critical to the global oil and gas business. Not only can a well-managed asset integrity plan help operators identify and reduce safety risks before they escalate but focusing on asset integrity can also play a major role in both achieving operational excellence and extending the life of ageing assets. See also Asset integrity management systems
Eightfold Way (physics) Development Baryon_decuplet > Historical development > Development Historically, quarks were motivated by an understanding of flavour symmetry. First, it was noticed (1961) that groups of particles were related to each other in a way that matched the representation theory of SU(3). From that, it was inferred that there is an approximate symmetry of the universe which is parametrized by the group SU(3). Finally (1964), this led to the discovery of three light quarks (up, down, and strange) interchanged by these SU(3) transformations.
Fundamental theorem of finite abelian groups Examples Commutative_group > Examples In a commutative ring the invertible elements, or units, form an abelian multiplicative group. In particular, the real numbers are an abelian group under addition, and the nonzero real numbers are an abelian group under multiplication.
Myelin Sheath Demyelination Myelin_Sheath > Clinical significance > Demyelination A more serious case of myelin deterioration is called Canavan disease. The immune system may play a role in demyelination associated with such diseases, including inflammation causing demyelination by overproduction of cytokines via upregulation of tumor necrosis factor or interferon. MRI evidence that docosahexaenoic acid DHA ethyl ester improves myelination in generalized peroxisomal disorders.
Uniprocessor system Summary Uniprocessor_system A uniprocessor system is defined as a computer system that has a single central processing unit that is used to execute computer tasks. As more and more modern software is able to make use of multiprocessing architectures, such as SMP and MPP, the term uniprocessor is therefore used to distinguish the class of computers where all processing tasks share a single CPU. Most desktop computers are shipped with multiprocessing architectures since the 2010s. As such, this kind of system uses a type of architecture that is based on a single computing unit. All operations (additions, multiplications, etc.) are thus done sequentially on the unit.
Polar nuclei Microgametophyte Polar_nuclei > Related structures and functions > Microgametophyte The male gametophytes, or microgametophytes, that participate in double fertilization are contained within pollen grains. They develop within the microsporangia, or pollen sacs, of the anthers on the stamens. Each microsporangium contains diploid microspore mother cells, or microsporocytes. Each microsporocyte undergoes meiosis, forming four haploid microspores, each of which can eventually develop into a pollen grain.
Small nucleolar RNA SNORD63 Summary Small_nucleolar_RNA_SNORD63 In molecular biology, snoRNA U63 (also known as SNORD63) is a non-coding RNA (ncRNA) molecule which functions in the modification of other small nuclear RNAs (snRNAs). This type of modifying RNA is usually located in the nucleolus of the eukaryotic cell which is a major site of snRNA biogenesis. It is known as a small nucleolar RNA (snoRNA) and also often referred to as a guide RNA.
Representation of a Lie algebra Infinitesimal Lie group representations Lie_algebra_representation > Examples > Infinitesimal Lie group representations A Lie algebra representation also arises in nature. If ϕ {\displaystyle \phi }: G → H is a homomorphism of (real or complex) Lie groups, and g {\displaystyle {\mathfrak {g}}} and h {\displaystyle {\mathfrak {h}}} are the Lie algebras of G and H respectively, then the differential d e ϕ: g → h {\displaystyle d_{e}\phi :{\mathfrak {g}}\to {\mathfrak {h}}} on tangent spaces at the identities is a Lie algebra homomorphism. In particular, for a finite-dimensional vector space V, a representation of Lie groups ϕ: G → GL ⁡ ( V ) {\displaystyle \phi :G\to \operatorname {GL} (V)\,} determines a Lie algebra homomorphism d ϕ: g → g l ( V ) {\displaystyle d\phi :{\mathfrak {g}}\to {\mathfrak {gl}}(V)} from g {\displaystyle {\mathfrak {g}}} to the Lie algebra of the general linear group GL(V), i.e. the endomorphism algebra of V. For example, let c g ( x ) = g x g − 1 {\displaystyle c_{g}(x)=gxg^{-1}} . Then the differential of c g: G → G {\displaystyle c_{g}:G\to G} at the identity is an element of GL ⁡ ( g ) {\displaystyle \operatorname {GL} ({\mathfrak {g}})} .
Classifier constructions in sign languages Description Classifier_constructions_in_sign_languages > Description Classifiers also often co-occur with verbs. Not much is known yet about their syntax or phonology.Classifier constructions are produced from the perspective of the signer.
System of measurement Energy Systems_of_units > Non-standard units > Energy A ton of TNT equivalent, and its multiples the kiloton, the megaton, and the gigaton. Often used in stating the power of very energetic events such as explosions and volcanic events and earthquakes and asteroid impacts. A gram of TNT as a unit of energy has been defined as 1000 thermochemical calories (1,000 cal or 4,184 J). The atom bomb dropped on Hiroshima.
Network-attached storage Comparing with SAN Network_Attached_Storage > Description > Comparing with SAN One way to loosely conceptualize the difference between a NAS and a SAN is that NAS appears to the client OS (operating system) as a file server (the client can map network drives to shares on that server) whereas a disk available through a SAN still appears to the client OS as a disk, visible in disk and volume management utilities (along with client's local disks), and available to be formatted with a file system and mounted. Despite their differences, SAN and NAS are not mutually exclusive and may be combined as a SAN-NAS hybrid, offering both file-level protocols (NAS) and block-level protocols (SAN) from the same system. A shared disk file system can also be run on top of a SAN to provide filesystem services.
Adrenergic blocking agent Beta 1 blocker Adrenergic_blocking_agent > Mechanism of Action > Beta 1 blocker Eventually, a higher cardiac output(or an increased amount of perfusion to organs) will be resulted. Moreover, more renin is released from the kidney to produce more angiotensin II, increasing the blood volume.
Topological string theory B-model Topological_B-model > Objects > B-model The B-model also contains fundamental strings, but their scattering amplitudes depend entirely upon the complex structure and are independent of the Kähler structure. In particular, they are insensitive to worldsheet instanton effects and so can often be calculated exactly. Mirror symmetry then relates them to A model amplitudes, allowing one to compute Gromov–Witten invariants.
Thermal efficiency Carnot efficiency Thermodynamic_efficiency > Heat engines > Carnot efficiency For example, the average automobile engine is less than 35% efficient. Carnot's theorem applies to thermodynamic cycles, where thermal energy is converted to mechanical work. Devices that convert a fuel's chemical energy directly into electrical work, such as fuel cells, can exceed the Carnot efficiency.
Image gradient Computer vision Image_gradient > Computer vision One of the most common uses is in edge detection. After gradient images have been computed, pixels with large gradient values become possible edge pixels. The pixels with the largest gradient values in the direction of the gradient become edge pixels, and edges may be traced in the direction perpendicular to the gradient direction.

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