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Economics of scale Learning and growth economies Economies_of_scale > Determinants of economies of scale > Learning and growth economies Learning and growth economies are at the base of dynamic economies of scale, associated with the process of growth of the scale dimension and not to the dimension of scale per se. Learning by doing implies improvements in the ability to perform and promotes the introduction of incremental innovations with a progressive lowering of average costs. Learning economies are directly proportional to the cumulative production (experience curve).
Disk integration Summary Disc_integration Disc integration, also known in integral calculus as the disc method, is a method for calculating the volume of a solid of revolution of a solid-state material when integrating along an axis "parallel" to the axis of revolution. This method models the resulting three-dimensional shape as a stack of an infinite number of discs of varying radius and infinitesimal thickness. It is also possible to use the same principles with rings instead of discs (the "washer method") to obtain hollow solids of revolutions. This is in contrast to shell integration, which integrates along an axis perpendicular to the axis of revolution.
Qualitative comparative analysis Criticism Qualitative_comparative_analysis > Criticism Crisp-Set QCA can be considered a special case of Multi-value QCA.Statistical methodologists have argued that QCA's strong assumptions render its findings both fragile and prone to type I error. Simon Hug argues that deterministic hypotheses and error-free measures are exceedingly rare in social science and uses Monte Carlo simulations to demonstrate the fragility of QCA results if either assumption is violated. Chris Krogslund, Donghyun Danny Choi, and Mathias Poertner further demonstrate that QCA results are highly sensitive to minor parametric and model-susceptibility changes and are vulnerable to type I error. Bear F. Braumoeller further explores the vulnerability of the QCA family of techniques to both type I error and multiple inference. Braumoeller also offers a formal test of the null hypothesis and demonstrates that even very convincing QCA findings may be the result of chance.
Combination problem Problem of mental causation Combination_problem > Arguments against > Problem of mental causation Robert Howell has argued that all causal functions are still accounted for dispositionally (i.e., in terms of the behaviors described by science), leaving phenomenality causally inert. He concludes, "This leaves us once again with epiphenomenal qualia, only in a very surprising place." Neutral monists reject such dichotomous views of mind-body interaction.
Glucose metabolism disorder Glycolysis Carbohydrate_metabolism > Metabolic pathways > Glycolysis During the second phase, chemical energy from the intermediates is transferred into ATP and NADH. The breakdown of one molecule of glucose results in two molecules of pyruvate, which can be further oxidized to access more energy in later processes.Glycolysis can be regulated at different steps of the process through feedback regulation. The step that is regulated the most is the third step.
Molecular Devices About Molecular Devices Molecular_Devices > About Molecular Devices Molecular Devices supplies analytical systems, including instruments, software, and reagents, to accelerate and improve drug discovery and basic life science research. Molecular Devices is based in Silicon Valley, CA, United States, and has regional offices in the United Kingdom, Germany, Korea, China, and Japan to support the global life sciences—drug discovery and basic research—communities.
Glossary of computer science S Glossary_of_computer_science > S For example, (M, A, R, Y) is a sequence of letters with the letter 'M' first and 'Y' last. This sequence differs from (A, R, M, Y). Also, the sequence (1, 1, 2, 3, 5, 8), which contains the number 1 at two different positions, is a valid sequence.
Tumor hypoxia GLUT1 transporter expression Hypoxic_tumor > Changes in the glycolytic pathway > GLUT1 transporter expression Moreover, transport of GLUT1 has been shown to increase under these hypoxic conditions. With the role of transporting sugars from the extracellular to the intracellular environment, GLUT1, along with other members of the GLUT family, can be rate-controlling for cellular glycolytic metabolism. Having an increased level of GLUT1, in the case of hypoxic tumors, increases the flux of glucose into the cells allowing for a higher rate of glycolysis and thus greater risks of metastasis (as elaborated upon below).
Charles Sanders Peirce Scientific method Logic_of_relatives > Philosophy > Pragmatism > Theory of inquiry > Scientific method In the pragmatic way of thinking about conceivable practical implications, every thing has a purpose, and, as possible, its purpose should first be denoted. Abduction hypothesizes an explanation for deduction to clarify into implications to be tested so that induction can evaluate the hypothesis, in the struggle to move from troublesome uncertainty to more secure belief. No matter how traditional and needful it is to study the modes of inference in abstraction from one another, the integrity of inquiry strongly limits the effective modularity of its principal components.
Glossary of computer hardware terms D Computer_terminology > D These modules are mounted on a printed circuit board and designed for use in personal computers, workstations and servers. Contrast SIMM. dual issue A superscalar pipeline capable of executing two instructions simultaneously. dynamic random-access memory (DRAM) A type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit and which must be periodically refreshed to retain the stored data.
Linear belief function Combination Linear_belief_function > Knowledge operations > Combination Here we use it to define the combination of two linear belief functions, which include normal distributions as a special case. Also, note that a vacuous linear belief function (0 swept matrix) is the neutral element for combination. When applying the equation, we need to consider two special cases.
Configuration space (physics) State space Configuration_space_(physics) > State space In quantum mechanics, the analogous concept is called the state space. A rather different set of formalisms and notation are used in this case. The analog of a "point particle" becomes a single point in C P 1 {\displaystyle \mathbb {CP} ^{1}} , the complex projective line, also known as the Bloch sphere. It is complex, because a quantum-mechanical wave function has a complex phase; it is projective because the wave-function is normalized to unit probability. That is, given a wave-function ψ {\displaystyle \psi } one is free to normalize it by the total probability ∫ ψ ∗ ψ {\textstyle \int \psi ^{*}\psi } , thus making it projective.
Subwavelength imaging Analysis of the diffraction limit Perfect_lens > Theory > Analysis of the diffraction limit A superlens is able to beat the diffraction limit. An example is the initial lens described by Pendry, which uses a slab of material with a negative index of refraction as a flat lens. In theory, a perfect lens would be capable of perfect focus – meaning that it could perfectly reproduce the electromagnetic field of the source plane at the image plane.
Jovian system Regular satellites Moons_of_Jupiter > Groups > Regular satellites These have prograde and nearly circular orbits of low inclination and are split into two groups: Inner satellites or Amalthea group: Metis, Adrastea, Amalthea, and Thebe. These orbit very close to Jupiter; the innermost two orbit in less than a Jovian day. The latter two are respectively the fifth and seventh largest moons in the Jovian system. Observations suggest that at least the largest member, Amalthea, did not form on its present orbit, but farther from the planet, or that it is a captured Solar System body.
Mitochondrial membrane O2 and NADH: energy-releasing reactions Oocyte_mitochondry > Function > Energy conversion > O2 and NADH: energy-releasing reactions The electrons from NADH and FADH2 are transferred to oxygen (O2) and hydrogen (protons) in several steps via an electron transport chain. NADH and FADH2 molecules are produced within the matrix via the citric acid cycle and in the cytoplasm by glycolysis. Reducing equivalents from the cytoplasm can be imported via the malate-aspartate shuttle system of antiporter proteins or fed into the electron transport chain using a glycerol phosphate shuttle.The major energy-releasing reactions that make the mitochondrion the "powerhouse of the cell" occur at protein complexes I, III and IV in the inner mitochondrial membrane (NADH dehydrogenase (ubiquinone), cytochrome c reductase, and cytochrome c oxidase). At complex IV, O2 reacts with the reduced form of iron in cytochrome c: O 2 + 4 H + ( aq ) + 4 Fe 2 + ( cyt c ) ⟶ 2 H 2 O + 4 Fe 3 + ( cyt c ) {\displaystyle {\ce {O2{}+4H+(aq){}+4Fe^{2+}(cyt\,c)->2H2O{}+4Fe^{3+}(cyt\,c)}}} Δ r G o ′ = − 218 kJ/mol {\displaystyle \Delta _{r}G^{o'}=-218{\text{ kJ/mol}}} releasing a lot of free energy from the reactants without breaking bonds of an organic fuel.
Second polar moment of area Limitations Second_polar_moment_of_area > Limitations The polar second moment of area is insufficient for use to analyze beams and shafts with non-circular cross-sections, due their tendency to warp when twisted, causing out-of-plane deformations. In such cases, a torsion constant should be substituted, where an appropriate deformation constant is included to compensate for the warping effect. Within this, there are articles that differentiate between the polar second moment of area, I z {\displaystyle I_{z}} , and the torsional constant, J t {\displaystyle J_{t}} , no longer using J {\displaystyle J} to describe the polar second moment of area.In objects with significant cross-sectional variation (along the axis of the applied torque), which cannot be analyzed in segments, a more complex approach may have to be used. See 3-D elasticity.
Ro-vibrational spectroscopy Raman spectra of diatomic molecules Ro-vibrational_spectroscopy > Linear molecules > Raman spectra of diatomic molecules The selection rule is Δ J = 0 , ± 2 {\displaystyle \Delta J=0,\pm 2} so that the spectrum has an O-branch (∆J = −2), a Q-branch (∆J = 0) and an S-branch (∆J=+2). In the approximation that B′′ = B′ = B the wavenumbers are given by ν ¯ ( S ( J ) ) = ω 0 + 4 B J + 6 B = ω 0 + 6 B , ω 0 + 10 B , ω 0 + 14 B , . . .
Galectin HIV Galectin > Galectins and disease > HIV In particular it is secreted in abundance by Th1 cells. In its normal function, galectin-1 binds to glycans on the CD4 co-receptor of T cells to prevent auto reactivity. When HIV is present, the galectin bridges between the CD4 co-receptor and gp120 ligands, thus facilitating HIV infection of the T cell.
Digital electronic computer Summary Digital_electronic_computer A digital electronic computer is not necessarily a transistorized computer: before the advent of the transistor, computers used vacuum tubes. The transistor enabled electronic computers to become much more powerful, and recent and future developments in digital electronics may enable humanity to build even more powerful electronic computers. One such possible development is the memristor.
Consumer behaviour Symbolic Consumer Behaviour Consumer_behaviour > Influences on purchase decision > Internal influences on purchase decision > Symbolic Consumer Behaviour Symbolic consumption: People consume not only the commodities themselves but also certain cultural and social significance symbolised or represented by them, including mood, beauty, grade, status, status, atmosphere, style, emotional appeal, etc. Symbolic consumption is typically reflected in brand consumption. Brand has three functions for consumers: functional value, symbolic value and experience value. Take luxury brands: The power of luxury brands is more than just their ability to convey identity.
Random forests History Random_Forest > Kernel random forest > History Lin and Jeon established the connection between random forests and adaptive nearest neighbor, implying that random forests can be seen as adaptive kernel estimates. Davies and Ghahramani proposed Random Forest Kernel and show that it can empirically outperform state-of-art kernel methods. Scornet first defined KeRF estimates and gave the explicit link between KeRF estimates and random forest. He also gave explicit expressions for kernels based on centered random forest and uniform random forest, two simplified models of random forest. He named these two KeRFs Centered KeRF and Uniform KeRF, and proved upper bounds on their rates of consistency.
Alternative approaches to redefining the kilogram Avogadro project Alternative_approaches_to_redefining_the_kilogram > Other approaches > Atom-counting approaches > Avogadro project All silicon-based approaches would fix the Avogadro constant but vary in the details of the definition of the kilogram. One approach would use silicon with all three of its natural isotopes present. About 7.78% of silicon comprises the two heavier isotopes: 29Si and 30Si.
Observation Science Observation > Science The scientific method requires observations of natural phenomena to formulate and test hypotheses. It consists of the following steps: Ask a question about a natural phenomenon Make observations of the phenomenon Formulate a hypothesis that tentatively answers the question Predict logical, observable consequences of the hypothesis that have not yet been investigated Test the hypothesis' predictions by an experiment, observational study, field study, or simulation Draw a conclusion from data gathered in the experiment, or revise the hypothesis or form a new one and repeat the process Write a descriptive method of observation and the results or conclusions reached Have peers with experience researching the same phenomenon evaluate the resultsObservations play a role in the second and fifth steps of the scientific method. However, the need for reproducibility requires that observations by different observers can be comparable. Human sense impressions are subjective and qualitative, making them difficult to record or compare.
Quantum informatics Scientific and engineering studies Quantum_telecommunications > Scientific and engineering studies The development of devices that can transmit quantum entangled particles is a significant scientific and engineering goal.Qiskit, Cirq and Q Sharp are popular quantum programming languages. Additional programming languages for quantum computers are needed, as well as a larger community of competent quantum programmers. To this end, additional learning resources are needed, since there are many fundamental differences in quantum programming which limits the amount of skills that can be carried over from traditional programming.
Position and momentum space Functions and operators in position space Position_and_momentum_spaces > Relation between space and reciprocal space > Functions and operators in position space Suppose we have a three-dimensional wave function in position space ψ(r), then we can write this functions as a weighted sum of orthogonal basis functions ψj(r): or, in the continuous case, as an integral It is clear that if we specify the set of functions ψ k ( r ) {\displaystyle \psi _{\mathbf {k} }(\mathbf {r} )} , say as the set of eigenfunctions of the momentum operator, the function ϕ ( k ) {\displaystyle \phi (\mathbf {k} )} holds all the information necessary to reconstruct ψ(r) and is therefore an alternative description for the state ψ {\displaystyle \psi } . In quantum mechanics, the momentum operator is given by (see matrix calculus for the denominator notation) with appropriate domain. The eigenfunctions are and eigenvalues ħk. So and we see that the momentum representation is related to the position representation by a Fourier transform.
Product integral Lebesgue-type product-integrals Product_integral > Lebesgue-type product-integrals Just like the Lebesgue version of (classical) integrals, one can compute product integrals by approximating them with the product integrals of simple functions. Each type of product integral has a different form for simple functions.
Displacement reaction Equations Metal-acid_reaction > Equations Chemical equations are used to graphically illustrate chemical reactions. They consist of chemical or structural formulas of the reactants on the left and those of the products on the right. They are separated by an arrow (→) which indicates the direction and type of the reaction; the arrow is read as the word "yields". The tip of the arrow points in the direction in which the reaction proceeds.
Adrenergic blocking agent Selective beta 3 blocker Adrenergic_blocking_agent > Agents > Selective beta 3 blocker Still under development == References ==
Renewable power Solar energy Renewable_Energy_Source > Mainstream technologies > Solar energy Australia has the largest proportion of solar electricity in the world, supplying 9.9% of the country's electrical demand in 2020. More than 30 per cent of Australian households now have rooftop solar PV, with a combined capacity exceeding 11 GW.There are, however, environmental implications of scaling up solar energy. In particular, the demand for raw materials such as aluminum poses concerns over the carbon footprint that will result from harvesting raw materials needed to implement solar energy.
String searching algorithm Classification by matching strategies String_searching > Classification of search algorithms > Classification by matching strategies Another one classifies the algorithms by their matching strategy: Match the prefix first (Knuth–Morris–Pratt, Shift-And, Aho–Corasick) Match the suffix first (Boyer–Moore and variants, Commentz-Walter) Match the best factor first (BNDM, BOM, Set-BOM) Other strategy (Naïve, Rabin–Karp)
Phagosome Inflammation Phagosome > Function > Inflammation Pathogen-infected apoptotic cells will trigger inflammation, but damaged cells that are degraded as part of the normal tissue turnover do not. The response also differs according to the opsonin-mediated phagocytosis. FcR and mannose receptor-mediated reactions produce pro-inflammatory reactive oxygen species and arachidonic acid molecules, but CR-mediated reactions do not result in those products.
Biomagnetism Summary Biomagnetism The present scientific definition took form in the 1970s, when an increasing number of researchers began to measure the magnetic fields produced by the human body. The first valid measurement was actually made in 1963, but the field of research began to expand only after a low-noise technique was developed in 1970. Today the community of biomagnetic researchers does not have a formal organization, but international conferences are held every two years, with about 600 attendees. Most conference activity centers on the MEG (magnetoencephalogram), the measurement of the magnetic field of the brain.
Grate heater Summary Grate_heater They work by having naturally convected and forced air funneled into the metal heat exchanger tubing that is then heated by the coals and/or fire. They draw in cold air from the floor and blow heated air back out into your home.
Bayesian Optimization Strategy Bayesian_Optimization > Strategy Bayesian optimization is typically used on problems of the form max x ∈ A f ( x ) {\textstyle \max _{x\in A}f(x)} , where A {\textstyle A} is a set of points, x {\textstyle x} , which rely upon less than 20 dimensions ( R d , d ≤ 20 {\textstyle \mathbb {R} ^{d},d\leq 20} ), and whose membership can easily be evaluated. Bayesian optimization is particularly advantageous for problems where f ( x ) {\textstyle f(x)} is difficult to evaluate due to its computational cost. The objective function, f {\textstyle f} , is continuous and takes the form of some unknown structure, referred to as a "black box". Upon its evaluation, only f ( x ) {\textstyle f(x)} is observed and its derivatives are not evaluated.Since the objective function is unknown, the Bayesian strategy is to treat it as a random function and place a prior over it.
Rooted binary tree Breadth-first order Complete_binary_tree > Common operations > Traversal > Breadth-first order Contrasting with depth-first order is breadth-first order, which always attempts to visit the node closest to the root that it has not already visited. See breadth-first search for more information. Also called a level-order traversal.
High blood sugar Medications High_blood_sugar > Causes > Medications Certain medications increase the risk of hyperglycemia, including: corticosteroids, octreotide, beta blockers, epinephrine, thiazide diuretics, statins, niacin, pentamidine, protease inhibitors, L-asparaginase, and antipsychotics. The acute administration of stimulants such as amphetamines typically produces hyperglycemia; chronic use, however, produces hypoglycemia. Thiazides are used to treat type 2 diabetes but it also causes severe hyperglycemia.
Phase Transitions and Critical Phenomena Contents Phase_Transitions_and_Critical_Phenomena > Contents 'Exact Combinatorial Algorithms: Ground States of Disordered Systems', by M.J. Alava, P.M. Duxbury, C.F.
Clique Social impact Clique > Social impact A clique may inhibit external social influence by impacting the emotions, opinions, or behaviors of group members. There are many ways in which the perception of information between members in a clique can influence other members on a greater level than if they had received the same information from a different source. For example, receiving information from a close friend or family member is interpreted and responded to differently from receiving the same information from someone who is not within the clique structure. The satisfaction, interaction, and closeness of an individual's clique groups develop and change throughout the years. Yet, there is always a constant morphing of both the individual and the group as time goes on.
Probability interpretation Summary Probability_interpretation There are also evidential interpretations of probability covering groups, which are often labelled as 'intersubjective' (proposed by Gillies and Rowbottom).Some interpretations of probability are associated with approaches to statistical inference, including theories of estimation and hypothesis testing. The physical interpretation, for example, is taken by followers of "frequentist" statistical methods, such as Ronald Fisher, Jerzy Neyman and Egon Pearson. Statisticians of the opposing Bayesian school typically accept the frequency interpretation when it makes sense (although not as a definition), but there's less agreement regarding physical probabilities.
Factorial number system Fractional values Factorial_number_system > Fractional values {\displaystyle 1/240=0.0\ 0\ 0\ 0\ 0\ 3_{!}} 1 / 360 = 0.0 0 0 0 0 2 ! {\displaystyle 1/360=0.0\ 0\ 0\ 0\ 0\ 2_{!}}
Wassim Michael Haddad Thermodynamics Wassim_Michael_Haddad > Research > Thermodynamics Haddad's Thermodynamics: A Dynamical Systems Approach, Princeton, NJ: Princeton University Press, 2005, develops a novel and unique system-theoretic framework of thermodynamics. Thermodynamics is one of the bedrock disciplines of physics and engineering, yet its foundation has been lacking rigor and clarity as very eloquently pointed out by the American mathematician and natural philosopher Clifford Truesdell. Over the years, researchers from the systems and control community have acknowledged the need for developing a solid foundation for thermodynamics. Haddad's book brings together a vast range of ideas and tools to construct a powerful framework for thermodynamics.
Sothic cycle Summary Sothic_cycle The Sothic cycle or Canicular period is a period of 1,461 Egyptian civil years of 365 days each or 1,460 Julian years averaging 365¼ days each. During a Sothic cycle, the 365-day year loses enough time that the start of its year once again coincides with the heliacal rising of the star Sirius (Ancient Egyptian: spdt or Sopdet, 'Triangle'; Greek: Σῶθις, Sō̂this) on 19 July in the Julian calendar. It is an important aspect of Egyptology, particularly with regard to reconstructions of the Egyptian calendar and its history. Astronomical records of this displacement may have been responsible for the later establishment of the more accurate Julian and Alexandrian calendars.
Hashimoto's disease Summary Hashimoto's_thyroiditis Furthermore, because it is common for untreated patients of Hashimoto's to develop hypothyroidism, further complications can include, but are not limited to, high cholesterol, heart disease, heart failure, high blood pressure, myxedema, and potential pregnancy problems.Hashimoto's thyroiditis is thought to be due to a combination of genetic and environmental factors. Risk factors include a family history of the condition and having another autoimmune disease. Diagnosis is confirmed with blood tests for TSH, T4, and antithyroid autoantibodies.
Comparison of DNS server software Summary Comparison_of_DNS_server_software This article presents a comparison of the features, platform support, and packaging of many independent implementations of Domain Name System (DNS) name server software.
Uncertainty tolerance Summary Ambiguity_intolerance Ambiguity tolerance–intolerance is a psychological construct that describes the relationship that individuals have with ambiguous stimuli or events. Individuals view these stimuli in a neutral and open way or as a threat.
RNA Structure DNA DNA_structure > Secondary structure > DNA Secondary structuree set of interactions between bases, i.e., which parts of strands are bound to each other. In DNA double helix, the two strands of DNA are held together by hydrogen bonds. The nucleotides on one strand base pairs with the nucleotide on the other strand. The secondary structure is responsible for the shape that the nucleic acid assumes.
Tin(II) selenide Use in energy harvesting Tin_selenide > Use in energy harvesting Such a material needs to have low total thermal conductivity, high electrical conductivity, and high Seebeck coefficient according to the thermoelectric figure of merit ZT. Even though the record-high efficiency is most likely due to low thermal conductivity of the crystal, the electronic structure may have as important role: SnSe has highly anisotropic valence band structure, which consists of multiple valleys that act as independent channels for very mobile, low effective-mass charge transport within, and heavy-carrier conductivity perpendicular to the layers. While, historically, lead telluride and silicon-germanium have been used, these materials have suffered from heat conduction through the material.At room temperature, the crystal structure of SnSe is Pnma.
ETA Systems Software ETA_Systems > Software This compiler retained vendor-specific programming performance features (known as the Q8* subroutine calls) in an era when supercomputer users were realizing the necessity of source code portability between architectures. Additionally, the compiler optimizations were not keeping up with existing technology as shown by the Japanese supercomputer vendors such as NEC, or at Cray Research and the newer minisupercomputer makers. In general, computer hardware manufacturers prior and up to that period tended to be weak on software. Libraries and available commercial and non-commercial (soon to be called open-source) applications help an installed base of machines. CDC was relatively weak in this area.
Drugs and sexual desire Indirect mechanism Drugs_and_sexual_desire > Drugs suppressing sexual desire > Indirect mechanism SSRIs reduce the re-uptake of serotonin back to the neurons, leading to an increase in serotonin level in the body. Due to the fact that serotonin can interfere with other neurotransmitters and hormones, for instance, sex hormones, SSRIs can therefore lower sexual desire.Apart from SSRIs, other types of drugs that could lower sexual desire are not intended to suppress libido originally. Thus, sexually active people are suggested to avoid the usage of the following drugs: Antihypertensive drugs Anti-anxiety drugs (e.g. benzodiazepines) Antipsychotic drugs Anticonvulsants Non-steroidal anti-inflammatory drugs (e.g. Antihistamine) Opioid Medical marijuana Recreational drugs
Atmospheric electrical Cosmic radiation Atmospheric_electrical > Description > Cosmic radiation The Earth, and almost all living things on it, are constantly bombarded by radiation from outer space. This radiation primarily consists of positively charged ions from protons to iron and larger nuclei derived sources outside the Solar System. This radiation interacts with atoms in the atmosphere to create an air shower of secondary ionising radiation, including X-rays, muons, protons, alpha particles, pions, and electrons. Ionization from this secondary radiation ensures that the atmosphere is weakly conductive, and the slight current flow from these ions over the Earth's surface balances the current flow from thunderstorms. Ions have characteristic parameters such as mobility, lifetime, and generation rate that vary with altitude.
Work (physics) Summary Work-energy_theorem In physics, work is the energy transferred to or from an object via the application of force along a displacement. In its simplest form, for a constant force aligned with the direction of motion, the work equals the product of the force strength and the distance traveled. A force is said to do positive work if when applied it has a component in the direction of the displacement of the point of application. A force does negative work if it has a component opposite to the direction of the displacement at the point of application of the force.For example, when a ball is held above the ground and then dropped, the work done by the gravitational force on the ball as it falls is positive, and is equal to the weight of the ball (a force) multiplied by the distance to the ground (a displacement).
Sink strainer Household use Sink_strainer > Household use In houses, sink strainers are often used as drain covers in sinks, showers and bathtubs. Water lines or kitchen systems can get gravel, deposits that break free, and other stray items in the line. Due to the velocity of the water pushing them, they can severely damage or clog devices installed in the flow stream of the water line, for example p-traps or pipes. A strainer is essentially a screen installed to allow water to pass through, but not larger items.
Social phobia Neurotransmitters Social_phobia > Mechanisms > Neurotransmitters Paroxetine, sertraline and fluvoxamine are three SSRIs that have been approved by the FDA to treat social anxiety disorder. Some researchers believe that SSRIs decrease the activity of the amygdala. There is also increasing focus on other candidate transmitters, e.g. norepinephrine and glutamate, which may be over-active in social anxiety disorder, and the inhibitory transmitter GABA, which may be under-active in the thalamus.
Venous translucence Light interaction with skin color Venous_translucence > Other considerations > Light interaction with skin color Skin is opaque to light. In physics light reception, heat or other type of radiant energy on the part of molecules is called absorption. When tissues are illuminated during translumination, some light is absorbed and some reflected. It is known that an object which absorbs all radiation is seen as black; the pigments that give color to the skin and the other tissues, absorb certain wavelengths of white light and transmit radiant energy.
Maxwell's Equations Relativistic formulations Maxwell’s_equations > Relativistic formulations The Maxwell equations can also be formulated on a spacetime-like Minkowski space where space and time are treated on equal footing. The direct spacetime formulations make manifest that the Maxwell equations are relativistically invariant. Because of this symmetry, the electric and magnetic fields are treated on equal footing and are recognized as components of the Faraday tensor. This reduces the four Maxwell equations to two, which simplifies the equations, although we can no longer use the familiar vector formulation.
Physical law Laws of chemistry Physical_law > Laws of chemistry Elemental equivalent weights can then be used to derive atomic weights for each element. More modern laws of chemistry define the relationship between energy and its transformations. Reaction kinetics and equilibriaIn equilibrium, molecules exist in mixture defined by the transformations possible on the timescale of the equilibrium, and are in a ratio defined by the intrinsic energy of the molecules—the lower the intrinsic energy, the more abundant the molecule.
Environmental isotopes Isotope geochemistry Environmental_isotopes > Isotope geochemistry These tracers have a certain distribution spatially, and so scientists need to deconvolve the different processes that affect these tracer distributions. One way tracer distributions are set is by conservative mixing. In conservative mixing, the amount of the tracer is conserved.
Electron-on-Helium Qubit Proposed quantum computing schemes – Rydberg, spin and orbital states Electron-on-Helium_Qubit > Proposed quantum computing schemes – Rydberg, spin and orbital states The electron trap was integrated into a superconducting coplanar cavity device. It was shown that, as in many superconducting qubit systems, the resonant exchange of microwave photons between the trapped electron and the cavity could be described by the Jaynes-Cummings Hamiltonian. Distant qubits could be coupled via a cavity bus. It was also shown that local magnetic field gradients could allow coupling between the electron spin state and the lateral motion, facilitating the read-out of the spin state via microwave spectroscopy of the cavity.
Hash value Folding Hash_algorithm > Hashing integer data types > Folding A folding hash code is produced by dividing the input into n sections of m bits, where 2m is the table size, and using a parity-preserving bitwise operation such as ADD or XOR to combine the sections, followed by a mask or shifts to trim off any excess bits at the high or low end. For example, for a table size of 15 bits and key value of 0x0123456789ABCDEF, there are five sections consisting of 0x4DEF, 0x1357, 0x159E, 0x091A and 0x8. Adding, we obtain 0x7AA4, a 15-bit value.
Intuitionistic set theory Total functional relations Intuitionistic_set_theory > Subtheories of ZF > Functions > Total functional relations Surjectivity is formally a more complex definition. Note that injectivity shall be defined positively, not by its contrapositive, which is common practice in classical mathematics. The version without negations is sometimes called weakly injective.
Diffraction topography History Diffraction_topography > History For a more detailed account of the historical development of topography, see J.F. Kelly – "A brief history of X-ray diffraction topography".From about the 1970s on, topography profited from the advent of synchrotron x-ray sources which provided considerably more intense x-ray beams, allowing to achieve shorter exposure times, better contrast, higher spatial resolution, and to investigate smaller samples or rapidly changing phenomena. Initial applications of topography were mainly in the field of metallurgy, controlling the growth of better crystals of various metals.
Likelihood principle Experimental design arguments on the likelihood principle Likelihood_principle > Arguments for and against > Experimental design arguments on the likelihood principle Example 2 – a more elaborated version of the same statistics Suppose a number of scientists are assessing the probability of a certain outcome (which we shall call 'success') in experimental trials. Conventional wisdom suggests that if there is no bias towards success or failure then the success probability would be one half. Adam, a scientist, conducted 12 trials and obtains 3 successes and 9 failures.
Atypical teratoid rhabdoid tumor Chemotherapy Atypical_teratoid_rhabdoid_tumor > Treatment > Chemotherapy Intrathecal protocols. One of the difficulties with brain and spinal tumors is that the blood brain barrier needs to be crossed so that the drug can get to the tumor. One mechanism to deliver the drug is through a device called an Ommaya reservoir.
Abl gene Regulation Abl_gene > Regulation There is some evidence that the expression of Abl is regulated by the microRNA miR-203.
Francis Crick Summary Francis_Crick He is widely known for the use of the term "central dogma" to summarise the idea that once information is transferred from nucleic acids (DNA or RNA) to proteins, it cannot flow back to nucleic acids. In other words, the final step in the flow of information from nucleic acids to proteins is irreversible.During the remainder of his career, he held the post of J.W.
Formal power series ring Introduction Ring_of_formal_power_series > Introduction If we studied this as a power series, its properties would include, for example, that its radius of convergence is 1. However, as a formal power series, we may ignore this completely; all that is relevant is the sequence of coefficients . In other words, a formal power series is an object that just records a sequence of coefficients.
Computer experiment Design of computer experiments Computer_experiment > Design of computer experiments The design of computer experiments has considerable differences from design of experiments for parametric models. Since a Gaussian process prior has an infinite dimensional representation, the concepts of A and D criteria (see Optimal design), which focus on reducing the error in the parameters, cannot be used. Replications would also be wasteful in cases when the computer simulation has no error. Criteria that are used to determine a good experimental design include integrated mean squared prediction error and distance based criteria . Popular strategies for design include latin hypercube sampling and low discrepancy sequences.
Physical unclonable function Concept Physical_unclonable_function > Concept When a physical stimulus is applied to the structure, it reacts in an unpredictable (but repeatable) way due to the complex interaction of the stimulus with the physical microstructure of the device. This exact microstructure depends on physical factors introduced during manufacture, which are unpredictable (like a fair coin). The applied stimulus is called the challenge, and the reaction of the PUF is called the response.
Virtual Private Network Provider-provisioned VPN building blocks Virtual_private_networking > Routing > Provider-provisioned VPN building blocks Customer edge device (CE)A device at the edge of the customer's network which provides access to the PPVPN. Sometimes it is just a demarcation point between provider and customer responsibility. Other providers allow customers to configure it.
Self-adjoint operator Definitions Symmetric_operator > Definitions A subset ρ ( A ) ⊆ C {\displaystyle \rho (A)\subseteq \mathbb {C} } is called the resolvent set (or regular set) if for every λ ∈ ρ ( A ) , {\displaystyle \lambda \in \rho (A),} the (not-necessarily-bounded) operator A − λ I {\displaystyle A-\lambda I} has a bounded everywhere-defined inverse. The complement σ ( A ) = C ∖ ρ ( A ) {\displaystyle \sigma (A)=\mathbb {C} \setminus \rho (A)} is called spectrum. In finite dimensions, σ ( A ) {\displaystyle \sigma (A)} consists exclusively of eigenvalues.
Coordination polymer Summary Coordination_polymer A coordination polymer is an inorganic or organometallic polymer structure containing metal cation centers linked by ligands. More formally a coordination polymer is a coordination compound with repeating coordination entities extending in 1, 2, or 3 dimensions.It can also be described as a polymer whose repeat units are coordination complexes. Coordination polymers contain the subclass coordination networks that are coordination compounds extending, through repeating coordination entities, in 1 dimension, but with cross-links between two or more individual chains, loops, or spiro-links, or a coordination compound extending through repeating coordination entities in 2 or 3 dimensions. A subclass of these are the metal-organic frameworks, or MOFs, that are coordination networks with organic ligands containing potential voids.Coordination polymers are relevant to many fields, having many potential applications.Coordination polymers can be classified in a number of ways according to their structure and composition.
Renal urea handling Summary Renal_urea_handling Preventing the loss of water in this manner is important if the person's body must save water in order to maintain a suitable blood pressure or (more likely) in order to maintain a suitable concentration of sodium ions in the blood plasma. About 40% of the urea filtered is normally found in the final urine, since there is more reabsorption than secretion along the nephron. It is regulated by antidiuretic hormone, which controls the amount reabsorbed in the collecting duct system and secreted into the loop of Henle.
Local blood flow regulation Individual Mechanisms Local_blood_flow_regulation > Individual Mechanisms Myogenic control, which originates from the wall of the blood vessel itself and consists of both muscle reflexes and products released from endothelial cells that line the vessel. These endothelial products include nitric oxide and endothelin-1 that are released in response to either chemical stimuli, like histamine, or increased shear stress on the blood vessel (meaning the amount of stress exerted by blood on the blood vessel walls). While nitric oxide causes vasodilation, endothelin-1 causes vasoconstriction.
Convolution theorem Convolution theorem for inverse Fourier transform Convolution_theorem > Convolution theorem for inverse Fourier transform Note that in the example below " ⋅ {\textstyle \cdot } " represents the Hadamard product, and " ∗ {\textstyle *} " represents a convolution between the two matrices. There is also a convolution theorem for the inverse Fourier transform so that
Micro processor Structure Microprocessor > Structure Instead of processing all of a long word on one integrated circuit, multiple circuits in parallel processed subsets of each word. While this required extra logic to handle, for example, carry and overflow within each slice, the result was a system that could handle, for example, 32-bit words using integrated circuits with a capacity for only four bits each. The ability to put large numbers of transistors on one chip makes it feasible to integrate memory on the same die as the processor. This CPU cache has the advantage of faster access than off-chip memory and increases the processing speed of the system for many applications. Processor clock frequency has increased more rapidly than external memory speed, so cache memory is necessary if the processor is not to be delayed by slower external memory.
Convulsion Signs and symptoms Convulsion > Signs and symptoms A person having a convulsion may experience several different symptoms, such as a brief blackout, confusion, drooling, loss of bowel or bladder control, sudden shaking of the entire body, uncontrollable muscle spasms, or temporary cessation of breathing. Symptoms usually last from a few seconds to several minutes, although they can last longer.Convulsions in children are not necessarily benign, and may lead to brain damage if prolonged. In these patients, the frequency of occurrence should not downplay their significance, as a worsening seizure state may reflect the damage caused by successive attacks. Symptoms may include: Lack of awareness Loss of consciousness Eyes rolling back Changes to breathing Stiffening of the arms, legs, or whole body Jerky movements of the arms, legs, body, or head Lack of control over movements Inability to respond
PCl3 Structure and spectroscopy Phosphorus_trichloride > Structure and spectroscopy It has a trigonal pyramidal shape. Its 31P NMR spectrum exhibits a singlet around +220 ppm with reference to a phosphoric acid standard.
Comparison of cryptographic hash functions General information Comparison_of_cryptographic_hash_functions > General information Basic general information about the cryptographic hash functions: year, designer, references, etc.
Characterizations of the exponential function Characterization 1 ⇔ characterization 5 Characterizations_of_the_exponential_function > Equivalence of the characterizations > Characterization 1 ⇔ characterization 5 Proof: 1 = f ( 0 ) = f ( x − x ) = f ( x ) f ( − x ) {\displaystyle 1=f(0)=f(x-x)=f(x)f(-x)} . If f ( x ) {\displaystyle f(x)} is continuous anywhere (say at x = y), then it is continuous everywhere. Proof: f ( x + δ ) − f ( x ) = f ( x − y ) → 0 {\displaystyle f(x+\delta )-f(x)=f(x-y)\to 0} as δ → 0 {\displaystyle \delta \to 0} by continuity at y.The second and third properties mean that it is sufficient to prove f ( x ) = e x {\displaystyle f(x)=e^{x}} for positive x. If f ( x ) {\displaystyle f(x)} is a Lebesgue-integrable function, then It then follows that Since f ( x ) {\displaystyle f(x)} is nonzero, some y can be chosen such that g ( y ) ≠ 0 {\displaystyle g(y)\neq 0} and solve for f ( x ) {\displaystyle f(x)} in the above expression.
Shell and tube heat exchanger Theory and application Shell-and-tube_heat_exchanger > Theory and application Two fluids, of different starting temperatures, flow through the heat exchanger. One flows through the tubes (the tube side) and the other flows outside the tubes but inside the shell (the shell side). Heat is transferred from one fluid to the other through the tube walls, either from tube side to shell side or vice versa. The fluids can be either liquids or gases on either the shell or the tube side.
Derivations of the Lorentz transformations Historical background Derivations_of_the_Lorentz_transformations > Historical background The usual treatment (e.g., Albert Einstein's original work) is based on the invariance of the speed of light. However, this is not necessarily the starting point: indeed (as is described, for example, in the second volume of the Course of Theoretical Physics by Landau and Lifshitz), what is really at stake is the locality of interactions: one supposes that the influence that one particle, say, exerts on another can not be transmitted instantaneously. Hence, there exists a theoretical maximal speed of information transmission which must be invariant, and it turns out that this speed coincides with the speed of light in vacuum. Newton had himself called the idea of action at a distance philosophically "absurd", and held that gravity had to be transmitted by some agent according to certain laws.Michelson and Morley in 1887 designed an experiment, employing an interferometer and a half-silvered mirror, that was accurate enough to detect aether flow.
Torque vectoring Electric vehicles Torque_vectoring > Functional description > Electric vehicles The detailed control system of the torque vectoring is described in the doctoral thesis of Dr.-Ing. Michael Graf.In case of electric vehicles with four electric motor drives, the same total wheel torque and yaw moment can be generated through a near infinite number of wheel torque distributions. Energy efficiency can be used as a criterion for allocating torque across the wheels. This approach is used in the Rivian R1T light-duty truck introduced in 2021.
Integrated constructed wetland Subsurface flow Integrated_constructed_wetland > Types and design considerations > Subsurface flow A downside to the system are the intakes, which can clog or bioclog easily, although some larger sized gravel will often solve this problem. Subsurface flow wetlands can be further classified as horizontal flow or vertical flow constructed wetlands. In the vertical flow constructed wetland, the effluent moves vertically from the planted layer down through the substrate and out (requiring air pumps to aerate the bed).
Number of genes Gene expression Gene_sequence > Gene expression In all organisms, two steps are required to read the information encoded in a gene's DNA and produce the protein it specifies. First, the gene's DNA is transcribed to messenger RNA (mRNA). : 6.1 Second, that mRNA is translated to protein. : 6.2 RNA-coding genes must still go through the first step, but are not translated into protein. The process of producing a biologically functional molecule of either RNA or protein is called gene expression, and the resulting molecule is called a gene product.
Static forces and virtual-particle exchange Summary Static_forces_and_virtual-particle_exchange Pions, photons, and gravitons fall into these respective categories. There are limits to the validity of the virtual particle picture.
Working mass Rockets and rocket-like reaction engines Reaction_mass > Rockets and rocket-like reaction engines This is not the case for most rockets however, where the rocket propellant is the working mass, as well as the energy source. This means that rockets stop accelerating as soon as they run out of fuel, regardless of other power sources they may have. This can be a problem for satellites that need to be repositioned often, as it limits their useful life. In general, the exhaust velocity should be close to the ship velocity for optimum energy efficiency. This limitation of rocket propulsion is one of the main motivations for the ongoing interest in field propulsion technology.
Chronic obstructive pulmonary disease Bronchodilators Chronic_obstructive_lung_disease > Management > Bronchodilators Indacaterol requires an inhaled dose once a day and is as effective as the other long-acting β2 agonist drugs that require twice-daily dosing for people with stable COPD.The two main anticholinergics used in COPD are ipratropium and tiotropium. Ipratropium is a short-acting muscarinic antagonist (SAMA), while tiotropium is long-acting (LAMA). Tiotropium is associated with a decrease in exacerbations and improved quality of life, and tiotropium provides those benefits better than ipratropium.
Friction burn Summary Friction_burn Friction burns are very common with clothing such as trousers on the knees caused by playing sport or sliding on wooden surfaces. Less dangerous friction burns can occur frequently on sensitive skin surfaces such as the genitals, such as during sexual intercourse or masturbation. The risks of a friction burn include infection and temporary or permanent scarring.
Analog Signal Processing Laplace transform Analog_Signal_Processing > Tools used in analog signal processing > Laplace transform The Laplace transform is a generalized Fourier transform. It allows a transform of any system or signal because it is a transform into the complex plane instead of just the jω line like the Fourier transform. The major difference is that the Laplace transform has a region of convergence for which the transform is valid.
Log structure Summary Log_structure In algebraic geometry, a log structure provides an abstract context to study semistable schemes, and in particular the notion of logarithmic differential form and the related Hodge-theoretic concepts. This idea has applications in the theory of moduli spaces, in deformation theory and Fontaine's p-adic Hodge theory, among others.
Social trap Subsequent experimentation Social_trap > Subsequent experimentation Subsequent empirical studies by other researchers explored aspects of social traps other than the underlying reinforcement structure. Studies tended to concentrate on manipulating social and cognitive variables. Cass and Edney (1978) created a simpler game using a bowl of nuts to simulate a commonly held resource. The Nuts Game as they called it had some distinct advantages over Brechner's electronically wired laboratory simulation.
C++ class Aggregate classes C++_class > Aggregate classes An aggregate class is a class with no user-declared constructors, no private or protected non-static data members, no base classes, and no virtual functions. Such a class can be initialized with a brace-enclosed comma-separated list of initializer-clauses. The following code has the same semantics in both C and C++.
Quantum multiverse Equivocal Quantum_multiverse > Reception > Equivocal They argue that macroscopic objects are significantly different from microscopic objects in not being isolated from the environment, and that using quantum formalism to describe them lacks explanatory and descriptive power and accuracy.Victor J. Stenger remarked that Murray Gell-Mann's published work explicitly rejects the existence of simultaneous parallel universes. Collaborating with James Hartle, Gell-Mann worked toward the development a more "palatable" post-Everett quantum mechanics. Stenger thought it fair to say that most physicists find the MWI too extreme, while noting it "has merit in finding a place for the observer inside the system being analyzed and doing away with the troublesome notion of wave function collapse".Richard Feynman, described as an Everettian in some sources, said of the MWI in 1982, "It's possible, but I'm not very happy with it."
Power factor (shooting sports) Summary Power_factor_(shooting_sports) Power Factor (PF) in practical shooting competitions refers to a ranking system used to reward cartridges with more recoil. Power factor is a measure of the momentum of the bullet (scaled product of the bullet's mass and velocity), which to some degree reflects the recoil impulse from the firearm onto the shooter (see section on limitations). Power factor is used in competitions sanctioned by the International Practical Shooting Confederation (IPSC), United States Practical Shooting Association (USPSA), Bianchi Cup, Steel Challenge and International Defensive Pistol Association (IDPA).
L'Hôpital's rule Special case Bernoulli's_rule > Proof of L'Hôpital's rule > Special case The proof of L'Hôpital's rule is simple in the case where f and g are continuously differentiable at the point c and where a finite limit is found after the first round of differentiation. It is not a proof of the general L'Hôpital's rule because it is stricter in its definition, requiring both differentiability and that c be a real number. Since many common functions have continuous derivatives (e.g. polynomials, sine and cosine, exponential functions), it is a special case worthy of attention. Suppose that f and g are continuously differentiable at a real number c, that f ( c ) = g ( c ) = 0 {\displaystyle f(c)=g(c)=0} , and that g ′ ( c ) ≠ 0 {\displaystyle g'(c)\neq 0} .
Hypertensive emergency Signs and symptoms Hypertensive_emergency > Signs and symptoms Symptoms may include headache, nausea, or vomiting. Chest pain may occur due to increased workload on the heart resulting in inadequate delivery of oxygen to meet the heart muscle's metabolic needs. The kidneys may be affected, resulting in blood or protein in the urine, and acute kidney failure.
Childhood schizophrenia Signs and symptoms Childhood_onset_schizophrenia > Signs and symptoms Delusions are reported in more than half of children with schizophrenia, but they are usually less complex than those of adults. Delusions are often connected with hallucinatory experiences. In one study, delusions were characterized as persecutory for the most part, but some children reported delusions of control. Many said they were being tortured by the beings causing their visual and auditory hallucinations, some thought disobeying their voices would cause them harm.Some degree of thought disorder was observed in a test group of children at Bellevue Hospital. They displayed illogicality, tangentiality (a serious disturbance in the associative thought process), and loosening of associations.Negative symptoms include apathy, avolition, and blunted emotional affect.
Harris matrix In use Harris_matrix > In use Such sites by definition produce multi-linear sequences of succession and to date the best way to get a handle of these sequences is to compile the matrix by hand, based on the drawings and the context sheets. This ensures an internally consistent record and that the complexity of the site is given due regard. Computer programmes do exist which can aid the production of a matrix, though at the moment these tend towards articulating linear sequences rather than multi-linear sequences. The Harris matrix is a tool that aids the accurate and consistent excavation of a site and articulates complex sequences in a clear and understandable way. Harris matrices play an invaluable role in the articulation of sequence and provide the building blocks from which higher order units of stratigraphically related events can be constructed.
Time integration methods Summary Time_stepping Numerical methods for ordinary differential equations are methods used to find numerical approximations to the solutions of ordinary differential equations (ODEs). Their use is also known as "numerical integration", although this term can also refer to the computation of integrals. Many differential equations cannot be solved exactly. For practical purposes, however – such as in engineering – a numeric approximation to the solution is often sufficient.
Glossary of mechanical engineering D Glossary_of_mechanical_engineering > D Differential –A differential is a gear train with three shafts that has the property that the rotational speed of one shaft is the average of the speeds of the others, or a fixed multiple of that average. Dimensionless number – is a quantity to which no physical dimension is assigned. Dimensionless quantities are widely used in many fields, such as mathematics, physics, chemistry, engineering, and economics.

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