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Pyramid Technology 90x Pyramid_Technology > Products > 90x During a subroutine call, the register stack moved up 32 words, so the caller's registers 32–47 became the called subroutine's registers 0–15. The return instruction dropped the stack by 32 words so return parameters would be visible to the caller in registers 32–47. The stack cache held 16 levels in the CPU and stack overflow and underflow was automatically handled by the microcode of the CPU.
Glossary of aerospace engineering H Glossary_of_aerospace_engineering > H Fluid dynamics has a wide range of applications, including calculating forces and moments on aircraft, determining the mass flow rate of petroleum through pipelines, predicting weather patterns, understanding nebulae in interstellar space and modelling fission weapon detonation. Hydrostatics – Fluid statics or hydrostatics is the branch of fluid mechanics that studies the condition of the equilibrium of a floating body and submerged body "fluids at hydrostatic equilibrium and the pressure in a fluid, or exerted by a fluid, on an immersed body". It encompasses the study of the conditions under which fluids are at rest in stable equilibrium as opposed to fluid dynamics, the study of fluids in motion.
Mean absolute difference Compared to standard deviation Mean_absolute_difference > Compared to standard deviation The mean absolute difference is twice the L-scale (the second L-moment), while the standard deviation is the square root of the variance about the mean (the second conventional central moment). The differences between L-moments and conventional moments are first seen in comparing the mean absolute difference and the standard deviation (the first L-moment and first conventional moment are both the mean). Both the standard deviation and the mean absolute difference measure dispersion—how spread out are the values of a population or the probabilities of a distribution. The mean absolute difference is not defined in terms of a specific measure of central tendency, whereas the standard deviation is defined in terms of the deviation from the arithmetic mean.
Trained immunity Summary Trained_immunity Trained immunity is a long-term functional modification of cells in the innate immune system which leads to an altered response to a second unrelated challenge. For example, the BCG vaccine leads to a reduction in childhood mortality caused by unrelated infectious agents. The term "innate immune memory" is sometimes used as a synonym for the term trained immunity which was first coined by Mihai Netea in 2011. The term "trained immunity" is relatively new – immunological memory has previously been considered only as a part of adaptive immunity – and refers only to changes in innate immune memory of vertebrates.
Rolling resistance All wheels Rolling_friction > Dependence on applied torque > All wheels "Applied torque" may either be driving torque applied by a motor (often through a transmission) or a braking torque applied by brakes (including regenerative braking). Such torques results in energy dissipation (above that due to the basic rolling resistance of a freely rolling, i.e. except slip resistance). This additional loss is in part due to the fact that there is some slipping of the wheel, and for pneumatic tires, there is more flexing of the sidewalls due to the torque. Slip is defined such that a 2% slip means that the circumferential speed of the driving wheel exceeds the speed of the vehicle by 2%.
Information entropy Differential entropy Entropy_(information_theory) > Entropy for continuous random variables > Differential entropy A precursor of the continuous entropy h is the expression for the functional Η in the H-theorem of Boltzmann. Although the analogy between both functions is suggestive, the following question must be set: is the differential entropy a valid extension of the Shannon discrete entropy? Differential entropy lacks a number of properties that the Shannon discrete entropy has – it can even be negative – and corrections have been suggested, notably limiting density of discrete points.
Quantum Cryptography Post-quantum cryptography Quantum_Cryptography > Post-quantum cryptography Surveys of post-quantum cryptography are available.There is also research into how existing cryptographic techniques have to be modified to be able to cope with quantum adversaries. For example, when trying to develop zero-knowledge proof systems that are secure against quantum adversaries, new techniques need to be used: In a classical setting, the analysis of a zero-knowledge proof system usually involves "rewinding", a technique that makes it necessary to copy the internal state of the adversary. In a quantum setting, copying a state is not always possible (no-cloning theorem); a variant of the rewinding technique has to be used.Post quantum algorithms are also called "quantum resistant", because – unlike quantum key distribution – it is not known or provable that there will not be potential future quantum attacks against them. Even though they may possibly be vulnerable to quantum attacks in the future, the NSA is announcing plans to transition to quantum resistant algorithms. The National Institute of Standards and Technology (NIST) believes that it is time to think of quantum-safe primitives.
Human performance modeling Situation Awareness (SA) Human_performance_modeling > Model Categories > Cognition & Memory > Decision-Making > Situation Awareness (SA) Models of SA range from descriptive (Endsley, 1995) to computational (Shively et al., 1997). The most useful model in HPM is that of McCarley et al. (2002) known as the A-SA model (Attention/Situation Awareness). It incorporates two semi-independent components: a perception/attention module and a cognitive SA-updated module. The P/A model of this A-SA model is based on the Theory of Visual Attention. (Bundesen, 1990) (refer to McCarley et al., 2002).
Scalability testing Advantages and disadvantages Scalability_testing > Vertical and horizontal scaling > Advantages and disadvantages There are advantages and disadvantages to both methods of scaling. Although scaling up may be simpler, the addition of hardware resources can result in diminishing returns. This means that every time we upgrade the processor for example, we do not always get the same level of benefits as the previous change. However, horizontal scaling can be extremely expensive, not only the cost of entire systems such as servers, but we must also take into account their regular maintenance costs .
Deuterium isotope effect Other examples Kinetic_isotope_effect > Case studies > Other examples Since the negative muon is much heavier than an electron, it orbits much closer to the nucleus, effectively shielding one proton, making Heμ to behave as 4.1H. With these exotic species, the reaction of H with 1H2 was investigated. Rate constants from reacting the lightest and the heaviest hydrogen analogues with 1H2 were then used to calculate the k0.11/k4.1 kinetic isotope effect, in which there is a 36.4 fold difference in isotopic masses.
Rheumatoid arthritis MicroRNAs Rheumatic_arthritis > Diagnosis > MicroRNAs MicroRNAs are a factor in the development of that type of disease. MicroRNAs usually operate as a negative regulator of the expression of target proteins and their increased concentration after biologic treatment (bDMARDs) or after anti-rheumatic drugs. Level of miRNA before and after anti-TNFa/DMRADs combination therapy are potential novel biomarkers for predicting and monitoring outcome.
Tumor metabolome Role of tumor suppressor and oncogenes Tumor_metabolome > Warburg effect and glycolysis > Role of tumor suppressor and oncogenes It provides resistance to oxidative stress that would regulates a set of genes that increase glucose metabolism and reduce mitochondrial respiration. This will provide additive force when the p53 is lost. Mutated Ras also enhances glycolysis, partly through increasing the activity of Myc and hypoxia-inducible factors. Although HIF-1 inhibits Myc, HIF-2 activates Myc causing the multiplicity of the tumor cells.
Tuberculosis diagnosis Tuberculin skin test Tuberculosis_diagnosis > Immunological test > Tuberculin skin test Two tests are available: the Mantoux and Heaf tests.
ZF 6HP transmission New Paradigm ZF_6HP_transmission > Specifications > New Paradigm The 6HP is the first transmission designed according to ZF's new paradigm. After gaining additional gear ratios only with additional components, this time the number of components has to decrease for the first time in spite of the necessity of even more ratios. Coming from 5 gear ratios made of 10 main components (gear sets, Ravigneaux considered as 2, brakes, clutches) to the 6 made of 8 now reflects, what major progress the Lepelletier gear mechanism means compared to conventional designs like the 5HP-family.
Emotional stress Other effects Psychological_stress > Physical effects > Other effects Experiments show that when healthy human individuals are exposed to acute laboratory stressors, they show an adaptive enhancement of some markers of natural immunity but a general suppression of functions of specific immunity. By comparison, when healthy human individuals are exposed to real-life chronic stress, this stress is associated with a biphasic immune response where partial suppression of cellular and humoral function coincides with low-grade, nonspecific inflammation.Even though psychological stress is often connected with illness or disease, most healthy individuals can still remain disease-free after confronting chronic stressful events.
Mathematical descriptions of the electromagnetic field Potential formulation Mathematical_descriptions_of_the_electromagnetic_field > Discussion > Potential formulation In advanced classical mechanics it is often useful, and in quantum mechanics frequently essential, to express Maxwell's equations in a potential formulation involving the electric potential (also called scalar potential) φ, and the magnetic potential (a vector potential) A. For example, the analysis of radio antennas makes full use of Maxwell's vector and scalar potentials to separate the variables, a common technique used in formulating the solutions of differential equations. The potentials can be introduced by using the Poincaré lemma on the homogeneous equations to solve them in a universal way (this assumes that we consider a topologically simple, e.g. contractible space). The potentials are defined as in the table above.
GeoDNS Summary GeoDNS This makes network access faster and possibly cheaper, compared to directing all users worldwide to the same server or to multiple servers using random distribution, such as round robin. As this technology is DNS based, it is much easier to deploy than BGP anycast. It does not require any support from the ISP and will not break existing connections when the server selected for a particular client changes.
Completing the square Completing the cube Completing_the_square > Completing the cube So, the change of variable t = x + b 3 a {\displaystyle t=x+{\frac {b}{3a}}} provides a cubic polynomial in t {\displaystyle t} without term of degree two, which is called the depressed form of the original polynomial. This transformation is generally the first step of the mehods for solving the general cubic equation. More generally, a similar transformation can be used for removing terms of degree n − 1 {\displaystyle n-1} in polynomials of degree n . {\displaystyle n.}
Condensed Matter Symmetry breaking Theoretical_condensed_matter_physics > Theoretical > Symmetry breaking Some states of matter exhibit symmetry breaking, where the relevant laws of physics possess some form of symmetry that is broken. A common example is crystalline solids, which break continuous translational symmetry. Other examples include magnetized ferromagnets, which break rotational symmetry, and more exotic states such as the ground state of a BCS superconductor, that breaks U(1) phase rotational symmetry.Goldstone's theorem in quantum field theory states that in a system with broken continuous symmetry, there may exist excitations with arbitrarily low energy, called the Goldstone bosons. For example, in crystalline solids, these correspond to phonons, which are quantized versions of lattice vibrations.
Analog Signal Processing Convolution Analog_Signal_Processing > Tools used in analog signal processing > Convolution Consider two waveforms f and g. By calculating the convolution, we determine how much a reversed function g must be shifted along the x-axis to become identical to function f. The convolution function essentially reverses and slides function g along the axis, and calculates the integral of their (f and the reversed and shifted g) product for each possible amount of sliding. When the functions match, the value of (f*g) is maximized. This occurs because when positive areas (peaks) or negative areas (troughs) are multiplied, they contribute to the integral.
Color coding in data visualization Grayscale, an important tool for visualization of data Color_coding_in_data_visualization > Grayscale, an important tool for visualization of data It can account for the spatial scale of the contrast.The derivative (slope) of nEPD with respect to background luminance implies an optimum background luminance. White backgrounds are used for historical reasons related to legibility of small symbols. However, there is no symbol size or symbol-luminance range for which a white background is optimum, in the sense of maximizing the number of visibly-different gray shades that symbols can have in this luminance range.
Aestivation hypothesis Dispute Aestivation_hypothesis > Dispute The theory has been disputed by a subsequent paper by Charles H. Bennett, Robin Hanson and Jess Riedel, who claim the notion that more computations could be performed later in the universe's history is based on a misunderstanding of the physics of computation. == References ==
Signed graphs Social psychology Signed_graphs > Applications > Social psychology Another illustration describes the changing international alliances between European powers in the decades before the First World War. They consider local triad dynamics and constrained triad dynamics, where in the latter case a relationship change is made only when the total number of unbalanced triads is reduced.
Decompression theory Decompression sickness Decompression_theory > Decompression sickness The inert gases used as substitutes for nitrogen have different solubility and diffusion characteristics in living tissues to the nitrogen they replace. For example, the most common inert gas diluent substitute for nitrogen is helium, which is significantly less soluble in living tissue, but also diffuses faster due to the relatively small size and mass of the He atom in comparison with the N2 molecule.Blood flow to skin and fat are affected by skin and core temperature, and resting muscle perfusion is controlled by the temperature of the muscle itself. During exercise increased flow to the working muscles is often balanced by reduced flow to other tissues, such as kidneys spleen and liver.
Radioactive radiation Summary Radioactive_radiation The word "ionize" refers to the breaking of one or more electrons away from an atom, an action that requires the relatively high energies that these electromagnetic waves supply. Further down the spectrum, the non-ionizing lower energies of the lower ultraviolet spectrum cannot ionize atoms, but can disrupt the inter-atomic bonds which form molecules, thereby breaking down molecules rather than atoms; a good example of this is sunburn caused by long-wavelength solar ultraviolet. The waves of longer wavelength than UV in visible light, infrared and microwave frequencies cannot break bonds but can cause vibrations in the bonds which are sensed as heat.
Asymptotically safe gravity Motivation Asymptotically_safe_gravity > Motivation At two-loop level the problematic divergences arise even in pure gravity. In order to overcome this conceptual difficulty the development of nonperturbative techniques was required, providing various candidate theories of quantum gravity. For a long time the prevailing view has been that the very concept of quantum field theory – even though remarkably successful in the case of the other fundamental interactions – is doomed to failure for gravity. By way of contrast, the idea of asymptotic safety retains quantum fields as the theoretical arena and instead abandons only the traditional program of perturbative renormalization.
Coefficients of expansion Summary Heat_expansion Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions.Temperature is a monotonic function of the average molecular kinetic energy of a substance. When a substance is heated, molecules begin to vibrate and move more, usually creating more distance between themselves. Substances which contract with increasing temperature are unusual, and only occur within limited temperature ranges (see examples below). The relative expansion (also called strain) divided by the change in temperature is called the material's coefficient of linear thermal expansion and generally varies with temperature. As energy in particles increases, they start moving faster and faster, weakening the intermolecular forces between them and therefore expanding the substance.
Chua circuit Chaotic criteria Chua's_circuit > Chaotic criteria An autonomous circuit made from standard components (resistors, capacitors, inductors) must satisfy three criteria before it can display chaotic behaviour. It must contain: one or more nonlinear elements, one or more locally active resistors, three or more energy-storage elements.Chua's circuit is the simplest electronic circuit meeting these criteria. As shown in the top figure, the energy storage elements are two capacitors (labeled C1 and C2) and an inductor (labeled L; L1 in lower figure). A "locally active resistor" is a device that has negative resistance and is active (it can amplify), providing the power to generate the oscillating current.
List of mathematical spaces Measurable, measure, and probability spaces Mathematical_space > Types of spaces > Measurable, measure, and probability spaces Thus, the volume of the body is the volume of its interior, and the interior can be exhausted by an infinite sequence of cubes. In contrast, the boundary of an arbitrary set of points can be of non-zero volume (an example: the set of all rational points inside a given cube). Measure theory succeeded in extending the notion of volume to a vast class of sets, the so-called measurable sets.
Temporary adjustments of theodolites Levelling Temporary_adjustments_of_theodolites > Levelling The bubble of the other level tube is then brought to the centre of the level tube by rotating the third foot screw either inward or outward. Repeat step 2 and step 3 in the same quadrant till both the bubble remain central. By rotating the upper part of the instrument through 180°, the level tube is brought parallel to first two-foot screws in reverse order.
Automata Theory Formal definition Automata_Theory > Automata > Formal definition AutomatonAn automaton can be represented formally by a quintuple M = ⟨ Σ , Γ , Q , δ , λ ⟩ {\displaystyle M=\langle \Sigma ,\Gamma ,Q,\delta ,\lambda \rangle } , where: Σ {\displaystyle \Sigma } is a finite set of symbols, called the input alphabet of the automaton, Γ {\displaystyle \Gamma } is another finite set of symbols, called the output alphabet of the automaton, Q {\displaystyle Q} is a set of states, δ {\displaystyle \delta } is the next-state function or transition function δ: Q × Σ → Q {\displaystyle \delta :Q\times \Sigma \to Q} mapping state-input pairs to successor states, λ {\displaystyle \lambda } is the next-output function λ: Q × Σ → Γ {\displaystyle \lambda :Q\times \Sigma \to \Gamma } mapping state-input pairs to outputs. If Q {\displaystyle Q} is finite, then M {\displaystyle M} is a finite automaton.Input word An automaton reads a finite string of symbols a 1 a 2 . . .
Blood poisoning Other Bacterial_sepsis > Management > Other Achieving partial or full enteral feeding (delivery of nutrients through a feeding tube) is chosen as the best approach to provide nutrition for a person who is contraindicated for oral intake or unable to tolerate orally in the first seven days of sepsis when compared to intravenous nutrition. However, omega-3 fatty acids are not recommended as immune supplements for a person with sepsis or septic shock. The usage of prokinetic agents such as metoclopramide, domperidone, and erythromycin are recommended for those who are septic and unable to tolerate enteral feeding. However, these agents may precipitate prolongation of the QT interval and consequently provoke a ventricular arrhythmia such as torsades de pointes. The usage of prokinetic agents should be reassessed daily and stopped if no longer indicated.
Hamiltonian complexity Quantum analog of the PCP theorem Hamiltonian_complexity > Quantum analog of the PCP theorem The classical PCP theorem states that simulating the ground states of classical systems is hard. The quantum analog of the PCP theorem concerns simulations of quantum systems. Proving the quantum analog of the PCP theorem is an open problem.
Abzyme Summary Abzyme So far, all catalytic antibodies produced have displayed only modest, weak catalytic activity. The reasons for low catalytic activity for these molecules have been widely discussed. Possibilities indicate that factors beyond the binding site may play an important role, in particular through protein dynamics. Some abzymes have been engineered to use metal ions and other cofactors to improve their catalytic activity.
TCP port Congestion control TCP_SYN > Protocol operation > Data transfer > Congestion control Modern implementations of TCP contain four intertwined algorithms: slow start, congestion avoidance, fast retransmit, and fast recovery.In addition, senders employ a retransmission timeout (RTO) that is based on the estimated round-trip time (RTT) between the sender and receiver, as well as the variance in this round-trip time. There are subtleties in the estimation of RTT. For example, senders must be careful when calculating RTT samples for retransmitted packets; typically they use Karn's Algorithm or TCP timestamps.
Grinker myelinopathy Diagnosis Grinker_myelinopathy > Diagnosis Grinker's myelinopathy is diagnosed by establishing a clinical history of carbon monoxide poisoning, narcotic overdose, myocardial infarction, or other global cerebral hypoxic events. This diagnosis can then be supported by neuroimaging confirmation of broadcast cerebral hemisphere demyelination sparing cerebellar and brainstem tracts. The neuroimaging evidence can also be used to diagnose Grinker's myelinopathy through an elevation in the concentrations of a myelin basic protein in the cerebrospinal fluid . Because this disease shares many of the symptoms with various forms of dementia or hysteria, these possibilities must be eliminated before a diagnosis for Grinker's myelinopathy can be made.
P-T extinction Ozone depletion P-T_extinction > Hypotheses about cause > Ozone depletion Malformed plant spores from the time of the extinction event show an increase in ultraviolet B absorbing compounds, confirming that increased ultraviolet radiation played a role in the environmental catastrophe and excluding other possible causes of mutagenesis, such as heavy metal toxicity, in these mutated spores.Multiple mechanisms could have reduced the ozone shield and rendered it ineffective. Computer modelling shows high atmospheric methane levels are associated with ozone shield decline and may have contributed to its reduction during the PTME. Volcanic emissions of sulphate aerosols into the stratosphere would have dealt significant destruction to the ozone layer.
Articulatory suppression Effects on working memory Articulatory_suppression > In the real world > Effects on working memory In summary, this study shows how articulatory suppression interfered with verbal working memory. Working memory works with both phonological loop and the visuospatial sketchpad, in the study performed by Jalbert and Saint-Aubin. They looked at the effects of articulatory suppression on visual similarity recall for where and when.
Syntagmatic analysis Application Syntagmatic_analysis > Application Due to the abstract nature of the signifier/signified relationship, a free-standing signifier is unable to convey knowledge or understanding by itself. After all, the only reason any word means what it means at all is due to a consensus of understanding by the wider community. Expanding on Saussure's own example of the arbitrariness of the word "tree", or any word for that matter, it can be seen that the word "tree" by itself could mean just about any upright bit of wood with branches, whether it grows leaves or provides a place to hang cups or hats. Meaning is therefore provided by an extended syntagmatic chain, which will identify for the reader of the text just what sort of tree is meant.
Epigenetics of autoimmune disorders Summary Epigenetics_of_autoimmune_disorders These diseases are classified as either local or systemic based upon whether they affect a single body system or if they cause systemic damage. Whether someone develops an autoimmune disorder is dependent on genetics as well as environmental factors. Some families show genetic predisposition for these conditions, however genetics alone is often not sufficient to explain whether someone will develop an autoimmune condition.
Unstable sort Bubble sort Sorting_algorithms > Popular sorting algorithms > Bubble sort and variants > Bubble sort Bubble sort is a simple sorting algorithm. The algorithm starts at the beginning of the data set. It compares the first two elements, and if the first is greater than the second, it swaps them. It continues doing this for each pair of adjacent elements to the end of the data set.
Polyclonal B cell response Recognition of pathogens Polyclonal_B_cell_response > B cell response > Recognition of pathogens Pathogens synthesize proteins that can serve as "recognizable" antigens; they may express the molecules on their surface or release them into the surroundings (body fluids). What makes these substances recognizable is that they bind very specifically and somewhat strongly to certain host proteins called antibodies. The same antibodies can be anchored to the surface of cells of the immune system, in which case they serve as receptors, or they can be secreted in the blood, known as soluble antibodies. On a molecular scale, the proteins are relatively large, so they cannot be recognized as a whole; instead, their segments, called epitopes, can be recognized.
Jean Baudrillard Simulacra and Simulation Jean_Baudrillard > Key concepts > Simulacra and Simulation He denies any possibility of a (mimetic) duplication of reality; reality mediated through language becomes a game of signs. In his theoretical system all distinctions between the real and the fictional, between a copy and the original, disappear".Simulation, Baudrillard claims, is the current stage of the simulacrum: all is composed of references with no referents, a hyperreality.
European Thermoelectric Society Meetings European_Thermoelectric_Society > Meetings The European countries take turns at organizing the annual European Conference on Thermoelectrics (ECT) showcasing trends, developments, products and services of academia and industry in the field. Every three years the ECT coincides with the International Conference on Thermoelectrics (ICT).
Aspirin Gastrointestinal Aspirin > Adverse effects > Gastrointestinal Buffering agents are intended to work by preventing the aspirin from concentrating in the walls of the stomach, although the benefits of buffered aspirin are disputed. Almost any buffering agent used in antacids can be used; Bufferin, for example, uses magnesium oxide. Other preparations use calcium carbonate. Gas-forming agents in effervescent tablet and powder formulations can also double as a buffering agent, one example being sodium bicarbonate, used in Alka-Seltzer.Taking vitamin C with aspirin has been investigated as a method of protecting the stomach lining. In trials vitamin C-releasing aspirin (ASA-VitC) or a buffered aspirin formulation containing vitamin C was found to cause less stomach damage than aspirin alone.
PH balance Three pH scales in oceanography PH > Applications > pH in the ocean > Three pH scales in oceanography Resulting in the following expression for SWS: SWS = F + + However, the advantage of considering this additional complexity is dependent upon the abundance of fluoride in the medium. In seawater, for instance, sulfate ions occur at much greater concentrations (>400 times) than those of fluoride. As a consequence, for most practical purposes, the difference between the total and seawater scales is very small. The following three equations summarize the three scales of pH: pHF = −log F pHT = −log(F + ) = −logT pHSWS = −log(H+]F + + ) = −logSWS
Thermo-magnetic motor Historical background Thermo-magnetic_motor > Historical background This technology dates back to 19th century, when a number of scientists submitted patents on the so-called "pyro-magnetic generators". These systems operate in a magnetic Brayton cycle, in a reverse way of the magnetocaloric refrigerators. Experiments have produced only extremely inefficient working prototypes, however, thermodynamic analysis indicate that thermomagnetic motors present high efficiency related to Carnot efficiency for small temperature differences around the magnetic material Curie temperature. The thermomagnetic motor principle has been studied as a possible actuator in smart materials, being successful in the generation of electric energy from ultra-low temperature gradients.
Calvin Cycle Steps Calvin-Benson-Bassham_cycle > Calvin cycle > Steps It can be seen that photorespiration has very negative consequences for the plant, because, rather than fixing CO2, this process leads to loss of CO2. C4 carbon fixation evolved to circumvent photorespiration, but can occur only in certain plants native to very warm or tropical climates—corn, for example. Furthermore, RuBisCO's catalyzing the light-independent reactions of photosynthesis generally exhibit an improved specificity for CO2 relative to O2, in order to minimize the oxygenation reaction. This improved specificity evolved after RuBisCO incorporated a new protein subunit.
Laminar flow reactor Flow velocity in LFR Laminar_flow_reactor > Flow velocity in LFR Turbulent flow, on the other hand, is irregular and travels at a higher speed. Therefore the flow velocity of a turbulent flow on one cross section is often assumed to be constant, or "flat". The "non-flat" flow velocity of laminar flow helps explain the mechanism of an LFR. For the fluid/gas moving in an LFR, the velocity near the center of the pipe is higher than the fluids near the wall of the pipe. Thus, the velocity distribution of the reactants tends to decrease from the center to the wall.
Pyroptosis Summary Pyroptosis A chronic form of inflammation ensues that ultimately contributes to tissue damage. Pyroptosis is associated with diseases including autoinflammatory, metabolic, and cardiovascular diseases, as well as cancer and neurodegeneration. Some examples of pyroptosis include the cell death induced in Salmonella-infected macrophages and abortively HIV-infected T helper cells.
Ionosonde Ionogram Ionosonde > Ionogram Data from ionograms may be used to measure changes in the Earth's ionosphere due to space weather events. Note that in the ionogram above the legend can be more clearly understood as having "Vx-" and "Vx+" to replace respectively "X-" and "X+". These refer to the vertical reflection of the eXtraordinary kind.
Function composition (computer science) Composing function calls Function_composition_(computer_science) > Composing function calls A nesting of too many functions may have the opposite effect, making the code less maintainable. In a stack-based language, functional composition is even more natural: it is performed by concatenation, and is usually the primary method of program design. The above example in Forth: g f Which will take whatever was on the stack before, apply g, then f, and leave the result on the stack. See postfix composition notation for the corresponding mathematical notation.
Functional near-infrared spectroscopy Description Functional_near-infrared_spectroscopy > Description The technique is safe, non-invasive, and can be used with other imaging modalities. fNIRS is a non-invasive imaging method involving the quantification of chromophore concentration resolved from the measurement of near infrared (NIR) light attenuation or temporal or phasic changes. The technique takes advantage of the optical window in which (a) skin, tissue, and bone are mostly transparent to NIR light (700–900 nm spectral interval) and (b) hemoglobin (Hb) and deoxygenated-hemoglobin (deoxy-Hb) are strong absorbers of light.
Greenhouse warming Radiative balance Greenhouse_Effect > Basic formulas > Radiative balance A planet's temperature will tend to shift towards a state of radiative equilibrium, in which the TOA energy imbalance is zero, i.e., E E I = 0 {\displaystyle \mathrm {EEI} =0} . When the planet is in radiative equilibrium, the overall effective temperature of the planet is given by T e f f = T r a d e q . {\displaystyle T_{\mathrm {eff} }=T_{\mathrm {radeq} }\;.} Thus, the concept of radiative equilibrium is important because it indicates what effective temperature a planet will tend towards having.If, in addition to knowing the effective temperature, T e f f {\displaystyle T_{\mathrm {eff} }} , we know the value of the greenhouse effect, then we know the mean (average) surface temperature of the planet. This is why the quantity known as the greenhouse effect is important: it is one of the few quantities that go into determining the planet's mean surface temperature.
DNA damage (naturally occurring) Summary DNA_damage_(naturally_occurring) DNA damage is an alteration in the chemical structure of DNA, such as a break in a strand of DNA, a nucleobase missing from the backbone of DNA, or a chemically changed base such as 8-OHdG. DNA damage can occur naturally or via environmental factors, but is distinctly different from mutation, although both are types of error in DNA. DNA damage is an abnormal chemical structure in DNA, while a mutation is a change in the sequence of base pairs. DNA damages cause changes in the structure of the genetic material and prevents the replication mechanism from functioning and performing properly.
Computer benchmark Challenges Benchmark_(computing) > Challenges Examples of unmeasured qualities of service include security, availability, reliability, execution integrity, serviceability, scalability (especially the ability to quickly and nondisruptively add or reallocate capacity), etc. There are often real trade-offs between and among these qualities of service, and all are important in business computing. Transaction Processing Performance Council Benchmark specifications partially address these concerns by specifying ACID property tests, database scalability rules, and service level requirements. In general, benchmarks do not measure Total cost of ownership.
Dual inheritance theory Reviews Dual_inheritance_theory > Further reading > Reviews "How culture shaped the human genome: bringing genetics and the human sciences together". Nature Reviews Genetics. 11 (2): 137–148.
Atmospheric optics Mirage Atmospheric_optics > Mirage A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. The word comes to English via the French mirage, from the Latin mirare, meaning "to look at, to wonder at". This is the same root as for "mirror" and "to admire". Also, it has its roots in the Arabic mirage.
Signal regeneration Summary Signal_regeneration In telecommunications, signal regeneration is signal processing that restores a signal, recovering its original characteristics.The signal may be electrical, as in a repeater on a T-carrier line, or optical, as in an OEO optical cross-connect. The process is used when it is necessary to change the signal type in order to transmit it via different media. Once it comes back to the original medium the signal is usually required to be regenerated so as to bring it back to its original state.
Charles's Law Relation to kinetic theory Charles's_Law > Relation to kinetic theory The kinetic theory of gases relates the macroscopic properties of gases, such as pressure and volume, to the microscopic properties of the molecules which make up the gas, particularly the mass and speed of the molecules. To derive Charles's law from kinetic theory, it is necessary to have a microscopic definition of temperature: this can be conveniently taken as the temperature being proportional to the average kinetic energy of the gas molecules, Ek: T ∝ E k ¯ . {\displaystyle T\propto {\bar {E_{\rm {k}}}}.\,} Under this definition, the demonstration of Charles's law is almost trivial. The kinetic theory equivalent of the ideal gas law relates PV to the average kinetic energy: P V = 2 3 N E k ¯ {\displaystyle PV={\frac {2}{3}}N{\bar {E_{\rm {k}}}}\,}
Enteric nervous system Further references Enteric_nervous_system > Further references Grosell M, Farrell A P and Brauner C J (Eds) (2010) Fish Physiology: The Multifunctional Gut of Fish Academic Press. ISBN 9780080961361. Gershon M. D. (1999), The Second Brain: A Groundbreaking New Understanding of Nervous Disorders of the Stomach and Intestine, Harper Perennial, ISBN 978-0060930721.
Glossary of engineering: A–L A Glossary_of_engineering:_A–L > A Absolute electrode potentialIn electrochemistry, according to an IUPAC definition, is the electrode potential of a metal measured with respect to a universal reference system (without any additional metal–solution interface). Absolute pressureIs zero-referenced against a perfect vacuum, using an absolute scale, so it is equal to gauge pressure plus atmospheric pressure. Absolute zeroThe lower limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as 0. Absolute zero is the point at which the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion.
Evolution of a random network Biology and medicine Evolution_of_a_random_network > Applications > Biology and medicine Phase transitions are used in research related to the functioning of proteins or emergence of diabetes on the cell-level. Neuroscience also extensively makes use of the model of the evolution of networks as phase-transition occur in neuron-networks.
Monad (functional programming) History Monads_in_functional_programming > History The term "monad" in programming actually goes all the way back to the APL and J programming languages, which do tend toward being purely functional. However, in those languages, "monad" is only shorthand for a function taking one parameter (a function with two parameters being a "dyad", and so on).The mathematician Roger Godement was the first to formulate the concept of a monad (dubbing it a "standard construction") in the late 1950s, though the term "monad" that came to dominate was popularized by category-theorist Saunders Mac Lane. The form defined above using bind, however, was originally described in 1965 by mathematician Heinrich Kleisli in order to prove that any monad could be characterized as an adjunction between two (covariant) functors.Starting in the 1980s, a vague notion of the monad pattern began to surface in the computer science community. According to programming language researcher Philip Wadler, computer scientist John C. Reynolds anticipated several facets of it in the 1970s and early 1980s, when he discussed the value of continuation-passing style, category theory as a rich source for formal semantics, and the type distinction between values and computations.
Minimum routing cost spanning tree Summary Minimum_routing_cost_spanning_tree The approximation works by choosing a number k {\displaystyle k} that depends on the approximation ratio but not on the number of vertices of the input graph, and by searching among all trees with k {\displaystyle k} internal nodes.The minimum routing cost spanning tree of an unweighted interval graph can be constructed in linear time. A polynomial time algorithm is also known for distance-hereditary graphs, weighted so that the weighted distances are hereditary. == References ==
Ekman flow Mathematical formulation Ekman_Layer > Mathematical formulation Different boundary conditions are appropriate for each of these different situations. Each of these situations can be accounted for through the boundary conditions applied to the resulting system of ordinary differential equations. The separate cases of top and bottom boundary layers are shown below.
Performance metric Identifying indicators Performance_metric > Identifying indicators They are rarely defined in such a way that their fulfillment would be hampered by factors seen as non-controllable by the organizations or individuals responsible. Such KPIs are usually ignored by organizations.KPIs should follow the SMART criteria. This means the measure has a Specific purpose for the business, it is Measurable to really get a value of the KPI, the defined norms have to be Achievable, the improvement of a KPI has to be Relevant to the success of the organization, and finally it must be Time phased, which means the value or outcomes are shown for a predefined and relevant period.KPIs should be set at a senior level within an organization and cascaded through all levels of management. In order to be evaluated, KPIs are linked to target values, so that the value of the measure can be assessed as meeting expectations or not. Key performance indicators are mostly the non-financial measures of a company's performance – they do not have a monetary value but in a business context they do contribute to the company's profitability.
DNA transposon Summary DNA_transposon DNA transposons are DNA sequences, sometimes referred to "jumping genes", that can move and integrate to different locations within the genome. They are class II transposable elements (TEs) that move through a DNA intermediate, as opposed to class I TEs, retrotransposons, that move through an RNA intermediate. DNA transposons can move in the DNA of an organism via a single-or double-stranded DNA intermediate. DNA transposons have been found in both prokaryotic and eukaryotic organisms.
Water justice Water as a critical resource Water_policies > Water as a critical resource The remaining unfrozen freshwater is mainly found as groundwater, with only a small fraction present in the air, or on the ground surface. Surface water is stored in wetlands or lakes or flows in a stream or river, and is the most commonly utilized resource for water. In places, surface water can be stored in a reservoir behind a dam, and then used for municipal and industrial water supply, for irrigation and to generate power in the form of hydroelectricity.
Sphincter of Oddi Function Sphincter_of_Oddi > Function The sphincter regulates the secretion of pancreatic juice and bile into the duodenum. It also prevents reflux of duodenal contents into the ampulla of Vater. By preventing reflux of the contents of the duodenum, the sphincter of Oddi prevents the accumulation of particulate matter and sludge in the bile ducts, reducing the risk of cholangitis. The sphincter of Oddi also allows retrograde filling of the gallbladder.The sphincter of Oddi is relaxed by the hormone cholecystokinin via vasoactive intestinal peptide.
Hologenome theory of evolution Definition Hologenome_theory_of_evolution > Theory > Definition The hologenome concept reboots elements of Lamarckian evolution V. Hologenomic variation integrates all mechanisms of mutation VI. Hologenomic evolution is most easily understood by equating a gene in the nuclear genome to a microbe in the microbiome VII. The hologenome concept fits squarely into genetics and accommodates multilevel selection theory VIII. The hologenome is shaped by selection and neutrality IX. Hologenomic speciation blends genetics and symbiosis X. Holobionts and their hologenomes do not change the rules of evolutionary biology
Wear patterns Impact Wear Wear_resistance > Wear types and mechanisms > Impact Wear Impact wear is caused by contact between two bodies. Unlike erosive wear, impact wear always occurs at the same, well-defined place. If the impact is repeated, then usually with constant kinetic energy at the moment of impact. The frequency of impacts can vary. Wear can occur on both bodies, but usually, one body has significantly higher hardness and toughness and its wear is neglected.
Unified Extensible Firmware Interface Linux Extensible_Firmware_Interface > Compatibility > Disk device compatibility > Linux Support for GPT in Linux is enabled by turning on the option CONFIG_EFI_PARTITION (EFI GUID Partition Support) during kernel configuration. This option allows Linux to recognize and use GPT disks after the system firmware passes control over the system to Linux. For reverse compatibility, Linux can use GPT disks in BIOS-based systems for both data storage and booting, as both GRUB 2 and Linux are GPT-aware. Such a setup is usually referred to as BIOS-GPT.
Antenna types Small loops Antenna_types > Loop > Small loops Small loops are called "magnetic loops", and if modified for resonance they are also called "tuned loops". Small receiving loops – Small receiving loops are sized at 1 /4~ 1 /10 wave perimeters, sometimes with many turns of wire around the same supporting frame. Small loops are widely used as compact direction finding antennas, since their "null" direction is exceptionally precise, and their small size makes them much more compact as hand-carried equipment than dipole-based directional antennas.Small transmitting loops – are small loop antennas specifically optimized for transmitting.
Zero point energy Chaotic and emergent phenomena Quantum_vacuum_zero_point_energy > Chaotic and emergent phenomena The idea that the vacuum energy can have multiple stable energy states is a leading hypothesis for the cause of cosmic inflation. In fact, it has been argued that these early vacuum fluctuations led to the expansion of the universe and in turn have guaranteed the non-equilibrium conditions necessary to drive order from chaos, as without such expansion the universe would have reached thermal equilibrium and no complexity could have existed. With the continued accelerated expansion of the universe, the cosmos generates an energy gradient that increases the "free energy" (i.e. the available, usable or potential energy for useful work) which the universe is able to utilize to create ever more complex forms of order.
Temperature-compensated balance wheel Temperature error Balance_wheels > History > Temperature error The two effects of increasing temperature on physical dimensions of the spring and the balance, the strengthening of the balance spring and the increase in rotational inertia of the balance, have opposing effects and to an extent cancel each other. The major effect of temperature which affects the rate of a watch is the weakening of the balance spring with increasing temperature. In a watch that is not compensated for the effects of temperature, the weaker spring takes longer to return the balance wheel back toward the center, so the ‘beat’ gets slower and the watch loses time. Ferdinand Berthoud found in 1773 that an ordinary brass balance and steel hairspring, subjected to a 60 °F (33 °C) temperature increase, loses 393 seconds (6+1⁄2 minutes) per day, of which 312 seconds is due to spring elasticity decrease.
High Luminosity Large Hadron Collider Physics goals High_Luminosity_Large_Hadron_Collider > Physics goals Major goals of HL-LHC thus belong to the following five categories; improved Standard Model measurements, searches for beyond the Standard Model (BSM) physics, flavor physics of heavy quarks and leptons, studies of the properties of the Higgs boson, and the studies of QCD matter at high density and temperature. Measurements of the Higgs boson and understanding its connection to the electroweak symmetry breaking remains the primary goal. In the domain of flavour physics; LHCb, ATLAS and CMS together will test the unitarity of the Cabibbo–Kobayashi–Maskawa matrix, and ATLAS and CMS will measure the properties of the top quark, the fermion with the largest known mass and largest Yukawa coupling.
Early evolution of life Summary History_of_life The earliest evidence of eukaryotes (complex cells with organelles) dates from 1.85 Ga, likely due to symbiogenesis between anaerobic archaea and aerobic proteobacteria in co-adaptation against the new oxidative stress. While eukaryotes may have been present earlier, their diversification accelerated when aerobic cellular respiration by the endosymbiont mitochondria provided a more abundant source of biological energy.
Instruction level parallelism Discussion Instruction-level_parallelism > Discussion Consider the following program: Operation 3 depends on the results of operations 1 and 2, so it cannot be calculated until both of them are completed. However, operations 1 and 2 do not depend on any other operation, so they can be calculated simultaneously. If we assume that each operation can be completed in one unit of time then these three instructions can be completed in a total of two units of time, giving an ILP of 3/2.
Busy beaver Nondeterministic Turing machines Busy_beaver > Related functions > Nondeterministic Turing machines The problem can be extended to Nondeterministic Turing machines by looking for the system with the most states across all branches or the branch with the longest number of steps. The question of whether a given NDTM will halt is still computationally irreducible, and the computation required to find an NDTM busy beaver is significantly greater than the deterministic case, since there are multiple branches that need to be considered. For a 2-state, 2-color system with p cases or rules, the table to the right gives the maximum number of steps before halting and maximum number of unique states created by the NDTM.
Gregory Grefenstette Awards Gregory_Grefenstette > Awards 2010 ACM Multimedia Grand Challenge Bronze award 2009 ACM Multimedia Grand Challenge, most practical system award 2007 three-year grant by Lagardere Foundation for work on semantic maps 1978 ITT International Fellow to Belgium == References ==
Velocity ratio Speed ratio Velocity_ratio > Speed ratio The speed ratio of two gears rolling without slipping on their pitch circles is given by, R = ω A ω B = r B r A , {\displaystyle R={\frac {\omega _{A}}{\omega _{B}}}={\frac {r_{B}}{r_{A}}},} therefore R = ω A ω B = N B N A . {\displaystyle R={\frac {\omega _{A}}{\omega _{B}}}={\frac {N_{B}}{N_{A}}}.} In other words, the gear ratio, or speed ratio, is inversely proportional to the radius of the pitch circle and the number of teeth of the input gear.
Jacobi eigenvalue algorithm Algorithm Jacobi_eigenvalue_algorithm > Algorithm The following algorithm is a description of the Jacobi method in math-like notation. It calculates a vector e which contains the eigenvalues and a matrix E which contains the corresponding eigenvectors; that is, e i {\displaystyle e_{i}} is an eigenvalue and the column E i {\displaystyle E_{i}} an orthonormal eigenvector for e i {\displaystyle e_{i}} , i = 1, ..., n. procedure jacobi(S ∈ Rn×n; out e ∈ Rn; out E ∈ Rn×n) var i, k, l, m, state ∈ N s, c, t, p, y, d, r ∈ R ind ∈ Nn changed ∈ Ln function maxind(k ∈ N) ∈ N ! index of largest off-diagonal element in row k m := k+1 for i := k+2 to n do if │Ski│ > │Skm│ then m := i endif endfor return m endfunc procedure update(k ∈ N; t ∈ R) ! update ek and its status y := ek; ek := y+t if changedk and (y=ek) then changedk := false; state := state−1 elsif (not changedk) and (y≠ek) then changedk := true; state := state+1 endif endproc procedure rotate(k,l,i,j ∈ N) !
Energy recovery ventilator Methods of transfer Energy_recovery_ventilation > Methods of transfer At this stage, the air passes through a primary unit and then into the space being conditioned. With this type of system, it is normal during the cooling seasons for the exhaust air to be cooler than the ventilation air and, during the heating seasons, warmer than the ventilation air. It is for this reason the system works efficiently and effectively. The coefficient of performance (COP) will increase as the conditions become more extreme (i.e., more hot and humid for cooling and colder for heating).
Machine ethics Practices Machine_ethics > Ethical frameworks and practices > Practices In March 2018, in an effort to address rising concerns over machine learning's impact on human rights, the World Economic Forum and Global Future Council on Human Rights published a white paper with detailed recommendations on how best to prevent discriminatory outcomes in machine learning. The World Economic Forum developed four recommendations based on the UN Guiding Principles of Human Rights to help address and prevent discriminatory outcomes in machine learning. The World Economic Forum's recommendations are as follows: Active Inclusion: the development and design of machine learning applications must actively seek a diversity of input, especially of the norms and values of specific populations affected by the output of AI systems Fairness: People involved in conceptualizing, developing, and implementing machine learning systems should consider which definition of fairness best applies to their context and application, and prioritize it in the architecture of the machine learning system and its evaluation metrics Right to Understanding: Involvement of machine learning systems in decision-making that affects individual rights must be disclosed, and the systems must be able to provide an explanation of their decision-making that is understandable to end users and reviewable by a competent human authority.
Direct neural interface Legal and social Direct_brain_interfaces > Ethical considerations > Legal and social Similar to how pharmaceutical science began as a balance for impairments and is now used to increase focus and reduce need for sleep, BCIs will likely transform gradually from therapies to enhancements. Efforts are made inside the BCI community to create consensus on ethical guidelines for BCI research, development and dissemination. As innovation continues, ensuring equitable access to BCIs will be crucial, failing which generational inequalities can arise which can adversely affect the right to human flourishing.The ethical considerations of BCIs are essential to the development of future implanted devices. End-users, ethicists, researchers, funding agencies, physicians, corporations, and all others involved in BCI use should consider the anticipated, and unanticipated, changes that BCIs will have on human autonomy, identity, privacy, and more.
Complex-oriented cohomology theory Summary Complex-orientable_cohomology_theory In algebraic topology, a complex-orientable cohomology theory is a multiplicative cohomology theory E such that the restriction map E 2 ( C P ∞ ) → E 2 ( C P 1 ) {\displaystyle E^{2}(\mathbb {C} \mathbf {P} ^{\infty })\to E^{2}(\mathbb {C} \mathbf {P} ^{1})} is surjective. An element of E 2 ( C P ∞ ) {\displaystyle E^{2}(\mathbb {C} \mathbf {P} ^{\infty })} that restricts to the canonical generator of the reduced theory E ~ 2 ( C P 1 ) {\displaystyle {\widetilde {E}}^{2}(\mathbb {C} \mathbf {P} ^{1})} is called a complex orientation. The notion is central to Quillen's work relating cohomology to formal group laws.If E is an even-graded theory meaning π 3 E = π 5 E = ⋯ {\displaystyle \pi _{3}E=\pi _{5}E=\cdots } , then E is complex-orientable.
Engineering fit Summary Slip_fit ISO and ANSI both group fits into three categories: clearance, location or transition, and interference. Within each category are several codes to define the size limits of the hole or shaft - the combination of which determines the type of fit. A fit is usually selected at the design stage according to whether the mating parts need to be accurately located, free to slide or rotate, separated easily, or resist separation. Cost is also a major factor in selecting a fit, as more accurate fits will be more expensive to produce, and tighter fits will be more expensive to assemble. Methods of producing work to the required tolerances to achieve a desired fit range from casting, forging and drilling for the widest tolerances through broaching, reaming, milling and turning to lapping and honing at the tightest tolerances.
Glossary of string theory A Glossary_of_string_theory > A ADHM Initials of Atiyah, Drinfeld, Hitchin, and Manin, as in the ADHM construction of instantons. ADM Initials of Arnowitt, Deser, and Misner, as in ADM energy, a way of defining the global energy in an asymptotically flat spacetime, or ADM decomposition of a metric, or ADM formalism. AdS Anti-de Sitter, as in anti-de Sitter space, a Lorentzian analogue of hyperbolic space AdS/CFT Anti-de Sitter/conformal field theory, especially the AdS/CFT correspondence.
Distributed file system for cloud Communication Distributed_file_system_for_cloud > Communication High performance of distributed file systems requires efficient communication between computing nodes and fast access to the storage systems. Operations such as open, close, read, write, send, and receive need to be fast, to ensure that performance. For example, each read or write request accesses disk storage, which introduces seek, rotational, and network latencies.The data communication (send/receive) operations transfer data from the application buffer to the machine kernel, TCP controlling the process and being implemented in the kernel. However, in case of network congestion or errors, TCP may not send the data directly.
Sustainable population Carrying capacity Sustainable_population > Carrying capacity Carrying capacity has been used as a tool in Neo-Malthusian arguments to limit population growth since the 1950s. The concept of carrying capacity has been applied to determining the population limits in Shanghai, a city faced with rapid urbanization.The application of the concept of carrying capacity for the human population, which exists in a non-equilibrium, has been criticized for not successfully being able to model the processes between humans and the environment. In popular discourse the concept is often used vaguely in the sense of a "balance between nature and human populations".In human ecology a popular definition from 1949 states "the maximum number of people that a given land area will maintain in perpetuity under a given system of usage without land degradation setting in".
Concept drift Benchmarks Concept_drift > External links > Benchmarks NAB: The Numenta Anomaly Benchmark, benchmark for evaluating algorithms for anomaly detection in streaming, real-time applications. (2014–2018)
Mathematical conjecture Summary Conjecture In mathematics, a conjecture is a conclusion or a proposition that is proffered on a tentative basis without proof. Some conjectures, such as the Riemann hypothesis (still a conjecture) or Fermat's Last Theorem (a conjecture until proven in 1995 by Andrew Wiles), have shaped much of mathematical history as new areas of mathematics are developed in order to prove them.
Steric factor Summary Steric_factor When collision theory is applied to reactions in solution, the solvent cage has an effect on the reactant molecules, as several collisions can take place in a single encounter, which leads to predicted preexponential factors being too large. ρ values greater than unity can be attributed to favorable entropic contributions.
Vasiliev equations Discrepancies between Vasiliev equations and Higher Spin Theories Vasiliev_equations > Discrepancies between Vasiliev equations and Higher Spin Theories . {\displaystyle \theta _{2,4,...}} are too non-local and lead to an infinite result for the AdS/CFT correlation functions. In three dimensions the Prokushkin–Vasiliev equations, which are supposed to describe interactions of matter fields with higher spin fields in three dimensions, are also affected by the aforementioned locality problem. For example, the perturbative corrections at the second order to the stress-tensors of the matter fields lead to infinite correlation functions. There is, however, another discrepancy: the spectrum of the Prokushkin–Vasiliev equations has, in addition to the matter fields (scalar and spinor) and higher spin fields, a set of unphysical fields that do not have any field theory interpretation, but interact with the physical fields.
The speed of light in vacuum In a medium Velocity_of_light > Propagation of light > In a medium Certain materials have an exceptionally low (or even zero) group velocity for light waves, a phenomenon called slow light. The opposite, group velocities exceeding c, was proposed theoretically in 1993 and achieved experimentally in 2000. It should even be possible for the group velocity to become infinite or negative, with pulses travelling instantaneously or backwards in time.
Rainbow tables Rainbow tables Rainbow_table > Rainbow tables These chains are not collision-free (they may overlap briefly) but they will not merge, drastically reducing the overall number of collisions.Using sequences of reduction functions changes how lookup is done: because the hash value of interest may be found at any location in the chain, it's necessary to generate k different chains. The first chain assumes the hash value is in the last hash position and just applies Rk; the next chain assumes the hash value is in the second-to-last hash position and applies Rk−1, then H, then Rk; and so on until the last chain, which applies all the reduction functions, alternating with H. This creates a new way of producing a false alarm: an incorrect "guess" of the position of the hash value may needlessly evaluate a chain. Although rainbow tables have to follow more chains, they make up for this by having fewer tables: simple hash chain tables cannot grow beyond a certain size without rapidly becoming inefficient due to merging chains; to deal with this, they maintain multiple tables, and each lookup must search through each table. Rainbow tables can achieve similar performance with tables that are k times larger, allowing them to perform a factor of k fewer lookups.
Valve voltmeter Analog voltmeter Volt_meter > Analog voltmeter For multi-range instruments, the input resistance varies as the instrument is switched to different ranges. Moving-coil instruments with a permanent-magnet field respond only to direct current.
Electric-field integral equation Summary Electric-field_integral_equation The electric-field integral equation is a relationship that allows the calculation of an electric field (E) generated by an electric current distribution (J).
Chemical polarity Polar molecules Polar_compound > Examples > Polar molecules In ozone (O3) molecules, the two O−O bonds are nonpolar (there is no electronegativity difference between atoms of the same element). However, the distribution of other electrons is uneven – since the central atom has to share electrons with two other atoms, but each of the outer atoms has to share electrons with only one other atom, the central atom is more deprived of electrons than the others (the central atom has a formal charge of +1, while the outer atoms each have a formal charge of −1⁄2). Since the molecule has a bent geometry, the result is a dipole across the whole ozone molecule.