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Exercise associated thermogenesis Shivering Exercise_associated_thermogenesis > Types > Shivering One method to raise temperature is through shivering. It produces heat because the conversion of the chemical energy of ATP into kinetic energy causes almost all of the energy to show up as heat. Shivering is the process by which the body temperature of hibernating mammals (such as some bats and ground squirrels) is raised as these animals emerge from hibernation. |
Dirac equation Further discussion of Lorentz covariance of the Dirac equation Dirac_mass > Further discussion of Lorentz covariance of the Dirac equation Both correspond to Lorentz transformations, but in different ways. The presentation here follows that of Itzykson and Zuber. |
Insulin sensitivity Summary Insulin_Resistance There are many causes of insulin resistance and the underlying process is still not completely understood. Risk factors for insulin resistance include obesity, sedentary lifestyle, family history of diabetes, various health conditions, and certain medications. |
Balsa wood bridge Testing Balsa_wood_bridge > Testing By using a mechanical or pneumatic testing device that pushes down on the bridge with increasing force until the bridge breaks. If such a testing device is used it is often equipped with a method of automatically gathering force data, such as a pressure sensor or load cell connected to a computer. This approach is more accurate at measuring bridges that have secondary structure that proves to be stronger than the primary structure. |
Shotgun proteomics Workflow Shotgun_proteomics > Workflow The selected ions undergo collision-induced dissociation or other process to induce fragmentation. The charged fragments are separated in the second stage of tandem mass spectrometry. The "fingerprint" of each peptide's fragmentation mass spectrum is used to identify the protein from which they derive by searching against a sequence database with commercially available software (e.g. Sequest or Mascot). |
Atropisomer Scope Atropisomer > Scope In one application the asymmetry in an atropisomer is transferred in a chemical reaction to a new stereocenter. The atropisomer is an iodoaryl compound synthesised starting from (S)-valine and exists as the (M,S) isomer and the (P,S) isomer. The interconversion barrier between the two is 24.3 kcal/mol (101.7 kJ/mol). The (M,S) isomer can be obtained exclusively from this mixture by recrystallisation from hexanes. |
Ion (chemistry) Ionic bonding Ion_notation > Chemistry > Ionic bonding Ionic bonding is a kind of chemical bonding that arises from the mutual attraction of oppositely charged ions. Ions of like charge repel each other, and ions of opposite charge attract each other. Therefore, ions do not usually exist on their own, but will bind with ions of opposite charge to form a crystal lattice. The resulting compound is called an ionic compound, and is said to be held together by ionic bonding. |
Machine-dependent software Summary Machine-dependent_software Organizations that want application software to work on heterogeneous computers may port that software to the other machines. Deploying machine-dependent applications on such architectures, such applications require porting. This procedure includes composing, or re-composing, the application's code to suit the target platform. |
Line (software) Features Line_(software) > Features Chats also provide bulletin boards on which users can post, like and comment. This application also has timeline and homepage features that allow users to post pictures, text and stickers on their homepages. Users can also change their Line theme to the theme Line provides in the theme shop for free or users can buy other famous cartoon characters they like. |
Rapid eye movement behavior disorder Summary REM_sleep_behavior_disorder The loss of motor inhibition leads to sleep behaviors ranging from simple limb twitches to more complex integrated movements that can be violent or result in injury to either the individual or their bedmates.RBD is a very strong predictor of progression to a synucleinopathy (usually Parkinson's disease or dementia with Lewy bodies). Melatonin is useful in the treatment of RBD. RBD was first described in 1986. |
Time lens Comparison with time lens imaging Time-stretch_analog-to-digital_converter > Comparison with time lens imaging Another technique, temporal imaging using a time lens, can also be used to slow down (mostly optical) signals in time. The time-lens concept relies on the mathematical equivalence between spatial diffraction and temporal dispersion, the so-called space-time duality. A lens held at a distance from an object produces a magnified image of the object. The lens imparts a quadratic phase shift to the spatial frequency components of the optical waves; in conjunction with the free space propagation (object to lens, lens to eye), this generates a magnified image. |
Mitotic phase Preprophase (plant cells) Mitosis > Phases > Mitosis > Preprophase (plant cells) In plant cells only, prophase is preceded by a pre-prophase stage. In highly vacuolated plant cells, the nucleus has to migrate into the center of the cell before mitosis can begin. This is achieved through the formation of a phragmosome, a transverse sheet of cytoplasm that bisects the cell along the future plane of cell division. In addition to phragmosome formation, preprophase is characterized by the formation of a ring of microtubules and actin filaments (called preprophase band) underneath the plasma membrane around the equatorial plane of the future mitotic spindle. |
Kinetic data structure Contrast with traditional data structures Kinetic_data_structure > Contrast with traditional data structures A kinetic data structure allows the values stored in it to change continuously with time. In principle, this can be approximated by sampling the position of the points at fixed intervals of time, and deleting and re-inserting each point into a "static" (traditional) data structure. However, such an approach is vulnerable to oversampling or undersampling, depending on what interval of time is used, and can also be wasteful of computational resources. |
Ricardo Vinuesa Most-cited Publications Ricardo_Vinuesa > Most-cited Publications Direct numerical simulation of the flow around a wing section at moderate Reynolds number International Journal of Heat and Fluid Flow 61, 117-128 (Cited108 times, according to Google Scholar.) Vinuesa R, Negi PS, Atzori M, Hanifi A, Henningson DS, Schlatter P. Turbulent boundary layers around wing sections up to Rec= 1,000,000. International Journal of Heat and Fluid Flow. |
Frederick W. Lanchester Aeronautics Frederick_W._Lanchester > Work > Aeronautics This is the basis of aerodynamics and the foundation of modern aerofoil theory. In 1894 he tested his theory on a number of models. In 1897 he presented a paper entitled "The soaring of birds and the possibilities of mechanical flight" to the Physical Society, but it was rejected, being too advanced for its time. |
Swimming-induced pulmonary edema Signs and symptoms Swimming-induced_pulmonary_edema > Signs and symptoms The diver feels that their breathing equipment is not working properly, with a high work of breathing, even though later tests indicate that the equipment was working correctly. A diver switching their demand valves, or using a buddy’s air supply, or repeatedly purging a rebreather may indicate the onset of SIPE, particularly if there is an adequate supply pressure, and may signal that they are out of gas, or reject a working alternative gas supply A diver may have difficulty breathing at the surface. Confusion or apparently irrational behaviour. |
Equivalence point Methods to determine the equivalence point Equivalence_point > Methods to determine the equivalence point This is differentiated from calorimetric titrimetry by the fact that the heat of the reaction (as indicated by temperature rise or fall) is not used to determine the amount of analyte in the sample solution. Instead, the equivalence point is determined by the rate of temperature change. Because thermometric titrimetry is a relative technique, it is not necessary to conduct the titration under isothermal conditions, and titrations can be conducted in plastic or even glass vessels, although these vessels are generally enclosed to prevent stray draughts from causing "noise" and disturbing the endpoint. |
Passive House Space heating Passive_House > Design and construction > Space heating A maximum air temperature of 50 °C (122 °F) is applied, to prevent any possible smell of scorching from dust that escapes the filters in the system. The air-heating element can be heated by a small heat pump, by direct solar thermal energy, annualized geothermal solar, or simply by a natural gas or oil burner. In some cases a micro-heat pump is used to extract additional heat from the exhaust ventilation air, using it to heat either the incoming air or the hot water storage tank. |
History of automated adaptive instruction in computer applications Chronology of developments in the field History_of_automated_adaptive_instruction_in_computer_applications > Chronology of developments in the field Clippy becomes relatively notorious among some Office users, who complain that the agent is intrusive and annoying. 1996. Oppermann & Thomas describe an approach for Supporting Learning as an Iterative Process where users of an application to be learned can acquire usage knowledge iteratively by experience, annotations and individual or cooperative recourses to prior knowledge. |
Intuitionistic set theory Choice functions Intuitionistic_set_theory > Subtheories of ZF > Choice functions Via the bounded separation axiom in E C S T {\displaystyle {\mathsf {ECST}}} , the principle also is equivalent to a schema in two bounded predicate variables: Keeping all quantifiers ranging over z {\displaystyle z} , one may further narrow this set domain using a unary Δ 0 {\displaystyle \Delta _{0}} -predicate variable, while also using any 2-ary Δ 0 {\displaystyle \Delta _{0}} -predicate instead of the relation set R {\displaystyle R} . Relativized dependent choice R D C {\displaystyle {\mathrm {RDC} }}: This is the schema just using two general classes, instead of requiring z {\displaystyle z} and R {\displaystyle R} be sets. The domain of the choice function granted to exist is still just ω {\displaystyle \omega } . |
End stage kidney disease Stages End-stage_renal_disease > Diagnosis > Stages Stage 1: Slightly diminished function; kidney damage with normal or relatively high GFR (≥90 mL/min/1.73 m2) and persistent albuminuria. Kidney damage is defined as pathological abnormalities or markers of damage, including abnormalities in blood or urine tests or imaging studies. Stage 2: Mild reduction in GFR (60–89 mL/min/1.73 m2) with kidney damage. |
XOR linked list Binary search tree XOR_linked_list > Variations > Binary search tree The XOR linked list concept can be generalized to XOR binary search trees. |
Insect flight Clap and fling Clap_and_fling > Mechanisms > Aerodynamics > Clap and fling Next, the wings pronate and utilize the leading edge during an upstroke rowing motion. As the clap motion begins, the leading edges meet and rotate together until the gap vanishes. Initially, it was thought that the wings were touching, but several incidents indicate a gap between the wings and suggest it provides an aerodynamic benefit.Lift generation from the clap and fling mechanism occurs during several processes throughout the motion. |
History of climate change science First calculations of greenhouse effect, 1896 History_of_climate_change_science > Prior to the 20th century > First calculations of greenhouse effect, 1896 On the other hand, a reduction of the quantity of carbon dioxide in the atmosphere to an amount ranging from 55 to 62 per cent, of the present content, would reduce the average temperature 4 or 5 C, which would bring on a glaciation comparable to that of the Pleistocene period. b. A second effect of increase and decrease in the amount of atmospheric carbon dioxide is the equalization, on the one hand, of surface temperatures, or their differentiation on the other. The temperature of the surface of the earth varies with latitude, altitude, the distribution of land and water, day and night, the seasons, and some other elements that may here be neglected. |
Glossary of mechanical engineering F Glossary_of_mechanical_engineering > F There are several types of friction including static friction between non-moving surfaces and kinetic friction between moving surfaces; for two given solid surfaces, static friction is greater than kinetic friction. Fluid friction describes the friction between layers of a viscous fluid that are moving relative to each other. Front wheel drive – Fundamentals of Engineering exam – Fusible plug – Fusion Deposition Modelling – |
Limit points Accumulation points of sequences and nets Ω-accumulation_point > Definition > Accumulation points of sequences and nets Note that there is already the notion of limit of a sequence to mean a point x {\displaystyle x} to which the sequence converges (that is, every neighborhood of x {\displaystyle x} contains all but finitely many elements of the sequence). That is why we do not use the term limit point of a sequence as a synonym for accumulation point of the sequence. The concept of a net generalizes the idea of a sequence. |
Introduction to electromagnetism Summary Introduction_to_electromagnetism Albert Einstein showed that the magnetic field arises through the relativistic motion of the electric field and thus magnetism is merely a side effect of electricity. The modern theoretical treatment of electromagnetism is as a quantum field in quantum electrodynamics. In many situations of interest to electrical engineering, it is not necessary to apply quantum theory to get correct results. |
Characterization theorem Summary Characterization_(mathematics) Characterization is not unique to mathematics, but since the science is abstract, much of the activity can be described as "characterization". For instance, in Mathematical Reviews, as of 2018, more than 24,000 articles contain the word in the article title, and 93,600 somewhere in the review. In an arbitrary context of objects and features, characterizations have been expressed via the heterogeneous relation aRb, meaning that object a has feature b. For example, b may mean abstract or concrete. The objects can be considered the extensions of the world, while the features are expression of the intensions. A continuing program of characterization of various objects leads to their categorization. |
Toponomics Summary Toponomics Toponomics is a discipline in systems biology, molecular cell biology, and histology concerning the study of the toponome of organisms. It is the field of study that purposes to decode the complete toponome in health and disease (the human toponome project)—which is the next big challenge in human biotechnology after having decoded the human genome.A toponome is the spatial network code of proteins and other biomolecules in morphologically intact cells and tissues.The spatial organization of biomolecules in cells is directly revealed by imaging cycler microscopy with parameter- and dimension-unlimited functional resolution. The resulting toponome structures are hierarchically organized and can be described by a three symbol code. |
Stratospheric sulfate aerosols (geoengineering) Pollution controls and the discovery of radiative effects Stratospheric_aerosol_injection > Scientific basis > Pollution controls and the discovery of radiative effects and Europe, they have also peaked in the recent years. In 2005, China was the largest polluter, with its estimated 25,490,000 short tons (23.1 Mt) emissions increasing by 27% since 2000 alone and roughly matching the U.S. |
Basal animal Cyanobacteria Marine_Biodiversity > Primary producers > Cyanobacteria The first primary producers that used photosynthesis were oceanic cyanobacteria about 2.3 billion years ago. The release of molecular oxygen by cyanobacteria as a by-product of photosynthesis induced global changes in the Earth's environment. Because oxygen was toxic to most life on Earth at the time, this led to the near-extinction of oxygen-intolerant organisms, a dramatic change which redirected the evolution of the major animal and plant species.The tiny marine cyanobacterium Prochlorococcus, discovered in 1986, forms today part of the base of the ocean food chain and accounts for much of the photosynthesis of the open ocean and an estimated 20% of the oxygen in the Earth's atmosphere. |
Network infrastructure Internet protocol suite Networking_software > Communication protocols > Common protocols > Internet protocol suite The Internet protocol suite, also called TCP/IP, is the foundation of all modern networking. It offers connection-less and connection-oriented services over an inherently unreliable network traversed by datagram transmission using Internet protocol (IP). At its core, the protocol suite defines the addressing, identification, and routing specifications for Internet Protocol Version 4 (IPv4) and for IPv6, the next generation of the protocol with a much enlarged addressing capability. The Internet protocol suite is the defining set of protocols for the Internet. |
Maximum prospective short-circuit current Summary Maximum_prospective_short-circuit_current The prospective short-circuit current (PSCC), available fault current, or short-circuit making current is the highest electric current which can exist in a particular electrical system under short-circuit conditions. It is determined by the voltage and impedance of the supply system. It is of the order of a few thousand amperes for a standard domestic mains electrical installation, but may be as low as a few milliamperes in a separated extra-low voltage (SELV) system or as high as hundreds of thousands of amps in large industrial power systems. |
Liouville's theorem (differential algebra) Relationship with differential Galois theory Liouville's_theorem_(differential_algebra) > Relationship with differential Galois theory Liouville's theorem is sometimes presented as a theorem in differential Galois theory, but this is not strictly true. The theorem can be proved without any use of Galois theory. Furthermore, the Galois group of a simple antiderivative is either trivial (if no field extension is required to express it), or is simply the additive group of the constants (corresponding to the constant of integration). Thus, an antiderivative's differential Galois group does not encode enough information to determine if it can be expressed using elementary functions, the major condition of Liouville's theorem. |
Supervised Machine Learning Generative training Supervised_Machine_Learning > Generative training The training methods described above are discriminative training methods, because they seek to find a function g {\displaystyle g} that discriminates well between the different output values (see discriminative model). For the special case where f ( x , y ) = P ( x , y ) {\displaystyle f(x,y)=P(x,y)} is a joint probability distribution and the loss function is the negative log likelihood − ∑ i log P ( x i , y i ) , {\displaystyle -\sum _{i}\log P(x_{i},y_{i}),} a risk minimization algorithm is said to perform generative training, because f {\displaystyle f} can be regarded as a generative model that explains how the data were generated. Generative training algorithms are often simpler and more computationally efficient than discriminative training algorithms. In some cases, the solution can be computed in closed form as in naive Bayes and linear discriminant analysis. |
Viterbi Algorithm Extensions Viterbi_Algorithm > Extensions Zied Baklouti created a generalized Viterbi algorithm with transfer learning, creating a flexible algorithm based on external features. A theory of modern information theory is also introduced using experiments based on an improved Viterbi algorithm A generalization of the Viterbi algorithm termed the max-sum algorithm (or max-product algorithm) can be used to find the most likely assignment of all or some subset of latent variables in a large number of graphical models, e.g. Bayesian networks, Markov random fields and conditional random fields. The latent variables need, in general, to be connected in a way somewhat similar to a hidden Markov model (HMM), with a limited number of connections between variables and some linear structure among the variables. The general algorithm involves message passing and is substantially similar to the belief propagation algorithm (which is the generalization of the forward-backward algorithm). |
DRTE Computer Transistor research DRTE_Computer > Transistor research The P-N-P-N circuit offered much higher power output, allowing it to drive a greater number of "downstream" circuits without additional amplifiers. The overall effect was to reduce, sometimes greatly, the total number of transistors needed to implement a digital circuit. Moody published his circuit in 1956. |
Diode-resistor logic Tunnel diodes Diode_logic > Tunnel diodes During the 1960s the use of tunnel diodes in logic circuits was an active research topic. When compared to transistor logic gates of the time, the tunnel diode offered much higher speeds. Unlike other diode types, the tunnel diode offered the possibility of amplification of signals at each stage. The operating principles of a tunnel diode logic rely on biasing of the tunnel diode and supply of current from inputs over a threshold current, to switch the diode between two states. |
Emotional and behavioral disorders Criteria Emotional_and_behavioral_disorders > Criteria An overall attitude of unhappiness or depression. A tendency to develop physical symptoms or fears related with individual or school issues.The term "EBD" includes students diagnosed with schizophrenia. However, it does not have any significant bearing on students who are socially maladjusted unless they also meet the above criteria. |
Chlorofluorocarbon Regulation Chlorofluorocarbon > History > Regulation Since the late 1970s, the use of CFCs has been heavily regulated because of their destructive effects on the ozone layer. After the development of his electron capture detector, James Lovelock was the first to detect the widespread presence of CFCs in the air, finding a mole fraction of 60 ppt of CFC-11 over Ireland. In a self-funded research expedition ending in 1973, Lovelock went on to measure CFC-11 in both the Arctic and Antarctic, finding the presence of the gas in each of 50 air samples collected, and concluding that CFCs are not hazardous to the environment. The experiment did however provide the first useful data on the presence of CFCs in the atmosphere. |
Fluid–structure interaction Examples Fluid–structure_interaction > Examples Another prominent example is the start up of a rocket engine, e.g. Space Shuttle main engine (SSME), where FSI can lead to considerable unsteady side loads on the nozzle structure. In addition to pressure-driven effects, FSI can also have a large influence on surface temperatures on supersonic and hypersonic vehicles.Fluid–structure interactions also play a major role in appropriate modeling of blood flow. Blood vessels act as compliant tubes that change size dynamically when there are changes to blood pressure and velocity of flow. |
Dyskeratosis congenita Research Dyskeratosis_congenita > Research Recent research has used induced pluripotent stem cells to study disease mechanisms in humans, and discovered that the reprogramming of somatic cells restores telomere elongation in dyskeratosis congenita (DKC) cells despite the genetic lesions that affect telomerase. The reprogrammed DKC cells were able to overcome a critical limitation in TERC levels and restored function (telomere maintenance and self-renewal). Therapeutically, methods aimed at increasing TERC expression could prove beneficial in DKC. |
Index locking Summary Index_locking Notable and widely researched are specialized techniques for B-trees (B-Tree concurrency control) which are regularly used as database indexes. Index locks are used to coordinate threads accessing indexes concurrently, and typically shorter-lived than the common transaction locks on user data. In professional literature, they are often called latches. |
Radar graph Applications Radar_graph > Applications An example of this where radar charts may be useful is the performance analysis of various sorting algorithms. A programmer could gather up several different sorting algorithms such as selection, bubble, and quick, then analyze the performance of these algorithms by measuring their speed, memory usage, and power usage, then graph these on a radar chart to see how each sort performs under various sizes of data. Another performance application is measuring the performance of similar cars against each other. |
Perstraction Summary Perstraction Perstraction is a membrane extraction process, where two liquid phases are contacted across a membrane. The desired species in the feed (solute), selectively crosses the membrane into the extracting solution. Perstraction was originally developed to overcome the downsides of liquid–liquid extraction, for example extractant toxicity and emulsion formation. Perstraction has been applied to many fields including fermentation, waste water treatment and alcohol-free beverage production. |
Metal ions in aqueous solution Oxo-aqua-cations Metal_ions_in_aqueous_solution > Solvation numbers and structures > Oxo-aqua-cations Vanadium(V) is believed to exist as the dioxo-ion + at pH less than 2, but the evidence for this ion depends on the formation of complexes, such as oxalate complexes which have been shown to have the VO+2 unit, with cis-VO bonds, in the solid state. The chromium(IV) ion 2+, similar to the vanadium ion has been proposed on the basis of indirect evidence.The uranyl ion, UO2+2, has a trans structure. The aqua ion UO2+2(aq) has five water molecules in the plane perpendicular to the O-U-O axis in a pentagonal bipyramid structure, point group D5h. Neptunyl and plutonyl have the same structure. Nothing is known of actinide(V) structures. |
Mechanical–electrical analogies Applications Mechanical-electrical_analogy > Applications This was of some importance in early phonographs where the audio is transmitted from the pickup needle to the horn through various mechanical components entirely without electrical amplification. Early phonographs suffered badly from unwanted resonances in the mechanical parts. It was found that these could be eliminated by treating the mechanical parts as components of a low-pass filter which has the effect of flattening out the passband.Electrical analogies of mechanical systems can be used just as a teaching aid, to help understand the behaviour of the mechanical system. In former times, up to about the early 20th century, it was more likely that the reverse analogy would be used; mechanical analogies were formed of the then little understood electrical phenomena. |
Finite Fourier transform Summary Finite_Fourier_transform In mathematics the finite Fourier transform may refer to either another name for discrete-time Fourier transform (DTFT) of a finite-length series. E.g., F.J.Harris (pp. 52–53) describes the finite Fourier transform as a "continuous periodic function" and the discrete Fourier transform (DFT) as "a set of samples of the finite Fourier transform". |
Solar power tower Summary Solar_power_tower A solar power tower, also known as 'central tower' power plant or 'heliostat' power plant, is a type of solar furnace using a tower to receive focused sunlight. It uses an array of flat, movable mirrors (called heliostats) to focus the sun's rays upon a collector tower (the target). Concentrating Solar Power (CSP) systems are seen as one viable solution for renewable, pollution-free energy.Early designs used these focused rays to heat water and used the resulting steam to power a turbine. Newer designs using liquid sodium have been demonstrated, and systems using molten salts (40% potassium nitrate, 60% sodium nitrate) as the working fluids are now in operation. These working fluids have high heat capacity, which can be used to store the energy before using it to boil water to drive turbines. Storing the heat energy for later recovery allows power to be generated continuously, while the sun is shining, and for several hours after the sun has set (or been clouded over). |
The Internet of Things Business planning and project management Internet_of_Everything > Adoption barriers > Business planning and project management According to 2018 study, 70–75% of IoT deployments were stuck in the pilot or prototype stage, unable to reach scale due in part to a lack of business planning.Even though scientists, engineers, and managers across the world are continuously working to create and exploit the benefits of IoT products, there are some flaws in the governance, management and implementation of such projects. Despite tremendous forward momentum in the field of information and other underlying technologies, IoT still remains a complex area and the problem of how IoT projects are managed still needs to be addressed. IoT projects must be run differently than simple and traditional IT, manufacturing or construction projects. Because IoT projects have longer project timelines, a lack of skilled resources and several security/legal issues, there is a need for new and specifically designed project processes. The following management techniques should improve the success rate of IoT projects: A separate research and development phase A Proof-of-Concept/Prototype before the actual project begins Project managers with interdisciplinary technical knowledge Universally defined business and technical jargon |
Fission-fusion society Humans Fission-fusion_society > Species > Primates > Humans Groups may begin to split due to arguments and disagreements. Among humans, gossip and language in general is also an important feature involved in fission-fusion. Communication keeps distant groups together although they may not be within close distances of each other. |
Mitochondrial shuttle Summary Mitochondrial_shuttle The mitochondrial shuttles are biochemical transport systems used to transport reducing agents across the inner mitochondrial membrane. NADH as well as NAD+ cannot cross the membrane, but it can reduce another molecule like FAD and that can cross the membrane, so that its electrons can reach the electron transport chain. The two main systems in humans are the glycerol phosphate shuttle and the malate-aspartate shuttle. The malate/a-ketoglutarate antiporter functions move electrons while the aspartate/glutamate antiporter moves amino groups. This allows the mitochondria to receive the substrates that it needs for its functionality in an efficient manner. |
The Corbomite Maneuver Plot The_Corbomite_Maneuver > Plot He explains that he was merely testing the Enterprise and its crew to discover their true intentions. As Kirk and company relax, Balok expresses a desire to learn more about humans and their culture, and suggests they allow a member of their crew to remain on his ship as an emissary of the Federation. Bailey happily volunteers, and Balok gives them a tour of his ship. |
Post-transition metals Summary Post-transition_metal Being close to the metal-nonmetal border, their crystalline structures tend to show covalent or directional bonding effects, having generally greater complexity or fewer nearest neighbours than other metallic elements. Chemically, they are characterised—to varying degrees—by covalent bonding tendencies, acid-base amphoterism and the formation of anionic species such as aluminates, stannates, and bismuthates (in the case of aluminium, tin, and bismuth, respectively). They can also form Zintl phases (half-metallic compounds formed between highly electropositive metals and moderately electronegative metals or metalloids). |
Thermodynamic arrow Cosmology Entropy_as_an_arrow_of_time > Current research > Cosmology The quantum fluctuations—which in the meantime have evolved into galaxies and stars—will be in superposition in such a way that the whole process described above is reversed—i.e., the fluctuations are erased by destructive interference and total uniformity is achieved once again. Thus the universe ends in a Big Crunch, which is similar to its beginning in the Big Bang. Because the two are totally symmetric, and the final state is very highly ordered, entropy must decrease close to the end of the universe, so that the Second Law of Thermodynamics reverses when the universe shrinks. |
Coot (software) Validation tools Coot_(software) > Features > Validation tools Check/Delete waters - check for water molecules which do not fit the density. Check waters by difference map variance Geometry analysis - check for improbable bond lengths, angles, etc. Peptide omega analysis - check for non-planar peptide bonds. Temperature factor variance analysis - GLN and ASN B-factor outliers - Rotamer analysis - check for unusual protein side-chain conformations. |
Atactic polypropylene Catalysts Polypropylene > Production > Catalysts The catalysts also contain organic modifiers, either aromatic acid esters and diesters or ethers. These catalysts are activated with special cocatalysts containing an organoaluminum compound such as Al(C2H5)3 and the second type of a modifier. The catalysts are differentiated depending on the procedure used for fashioning catalyst particles from MgCl2 and depending on the type of organic modifiers employed during catalyst preparation and use in polymerization reactions. |
Friability Summary Friability In materials science, friability ( FRY-ə-BIL-ə-tee), the condition of being friable, describes the tendency of a solid substance to break into smaller pieces under duress or contact, especially by rubbing. The opposite of friable is indurate. Substances that are designated hazardous, such as asbestos or crystalline silica, are often said to be friable if small particles are easily dislodged and become airborne, and hence respirable (able to enter human lungs), thereby posing a health hazard. Tougher substances, such as concrete, may also be mechanically ground down and reduced to finely divided mineral dust. |
Centered dot In mathematics and science Centered_dot > In mathematics and science The centered dot can be used when multiplying units, as in m · kg · s−2 for the newton expressed in terms of SI base units. However, when the decimal point is used as the decimal marker, as in the United States, the use of a centered dot for the multiplication of numbers or values of quantities is discouraged.In mathematics, a small middle dot can be used to represent multiplication; for example, x ⋅ y {\displaystyle x\cdot y} for multiplying x {\displaystyle x} by y {\textstyle y} . When dealing with scalars, it is interchangeable with the multiplication sign (×), as long as the multiplication sign is between numerals such that it would not be mistaken as variable x {\textstyle x} . |
Matrix theory Probability theory and statistics Empty_matrix > Applications > Probability theory and statistics Descriptive statistics is concerned with describing data sets, which can often be represented as data matrices, which may then be subjected to dimensionality reduction techniques. The covariance matrix encodes the mutual variance of several random variables. Another technique using matrices are linear least squares, a method that approximates a finite set of pairs (x1, y1), (x2, y2), ..., (xN, yN), by a linear function yi ≈ axi + b, i = 1, ..., Nwhich can be formulated in terms of matrices, related to the singular value decomposition of matrices.Random matrices are matrices whose entries are random numbers, subject to suitable probability distributions, such as matrix normal distribution. Beyond probability theory, they are applied in domains ranging from number theory to physics. |
Order picking Process Order_picking > Process Order processing is a sequential process involving: Picking: consists in taking and collecting articles in a specified quantity before shipment to satisfy customers' orders. Sorting: process that separates items according to destination. Pre-consolidation or package formation: includes weighting, labeling and packing. Consolidation: gathering packages into loading units for transportation, control and bill of lading. |
Consistent Histories Interpretation Consistent_Histories > Interpretation The logical equivalence between an empirical datum, which is a macroscopic phenomenon, and the result of a measurement, which is a quantum property, becomes clearer in the new approach, whereas it remained mostly tacit and questionable in the Copenhagen formulation. 2. There are two apparently distinct notions of probability in the new approach. |
Yang-Mills instanton Quantum mechanics Yang–Mills_instanton > Quantum mechanics An instanton can be used to calculate the transition probability for a quantum mechanical particle tunneling through a potential barrier. One example of a system with an instanton effect is a particle in a double-well potential. In contrast to a classical particle, there is non-vanishing probability that it crosses a region of potential energy higher than its own energy. |
Mechanical properties of biomaterials Elastic modulus Mechanical_properties_of_biomaterials > Elastic modulus Elastic modulus is simply defined as the ratio of stress to strain within the proportional limit. Physically, it represents the stiffness of a material within the elastic range when tensile or compressive loads are applied. It is clinically important because it indicates the selected biomaterial has similar deformable properties with the material it is going to replace. These force-bearing materials require high elastic modulus with low deflection. |
PH value Applications Ocean_acidity > Applications pKw is approximately 14 but depends on ionic strength and temperature, and so the pH of neutrality does also. Pure water and a solution of NaCl in pure water are both neutral, since dissociation of water produces equal numbers of both ions. However the pH of the neutral NaCl solution will be slightly different from that of neutral pure water because the hydrogen and hydroxide ions' activity is dependent on ionic strength, so Kw varies with ionic strength. |
Sinus perfectus Rule of 3-4-5 Right_angle > Rule of 3-4-5 Throughout history, carpenters and masons have known a quick way to confirm if an angle is a true "right angle". It is based on the most widely known Pythagorean triple (3, 4, 5) and so called the "rule of 3-4-5". From the angle in question, running a straight line along one side exactly 3 units in length, and along the second side exactly 4 units in length, will create a hypotenuse (the longer line opposite the right angle that connects the two measured endpoints) of exactly 5 units in length. This measurement can be made quickly and without technical instruments. The geometric law behind the measurement is the Pythagorean theorem ("The square of the hypotenuse of a right triangle is equal to the sum of the squares of the two adjacent sides"). |
Symmetric matrix Real symmetric matrices Symmetric_matrix > Properties > Real symmetric matrices If A {\displaystyle A} and B {\displaystyle B} are n × n {\displaystyle n\times n} real symmetric matrices that commute, then they can be simultaneously diagonalized: there exists a basis of R n {\displaystyle \mathbb {R} ^{n}} such that every element of the basis is an eigenvector for both A {\displaystyle A} and B {\displaystyle B} . Every real symmetric matrix is Hermitian, and therefore all its eigenvalues are real. (In fact, the eigenvalues are the entries in the diagonal matrix D {\displaystyle D} (above), and therefore D {\displaystyle D} is uniquely determined by A {\displaystyle A} up to the order of its entries.) Essentially, the property of being symmetric for real matrices corresponds to the property of being Hermitian for complex matrices. |
Vaccine trial Phase I Vaccine_trials > Phase I The Phase I study consists of introducing the vaccine candidate to assess its safety in healthy people. A vaccine Phase I trial involves normal healthy subjects, each tested with either the candidate vaccine or a "control" treatment, typically a placebo or an adjuvant-containing cocktail, or an established vaccine (which might be intended to protect against a different pathogen). The primary observation is for detection of safety (absence of an adverse event) and evidence of an immune response.After the administration of the vaccine or placebo, the researchers collect data on antibody production, on health outcomes (such as illness due to the targeted infection or to another infection). Following the trial protocol, the specified statistical test is performed to gauge the statistical significance of the observed differences in the outcomes between the treatment and control groups. |
Memory leak Programming issues Memory_leak > Programming issues (A strong reference is a reference that, unlike a weak reference, prevents an object from being garbage collected.) To prevent this, the developer is responsible for cleaning up references after use, typically by setting the reference to null once it is no longer needed and, if necessary, by deregistering any event listeners that maintain strong references to the object. In general, automatic memory management is more robust and convenient for developers, as they do not need to implement freeing routines or worry about the sequence in which cleanup is performed or be concerned about whether or not an object is still referenced. It is easier for a programmer to know when a reference is no longer needed than to know when an object is no longer referenced. However, automatic memory management can impose a performance overhead, and it does not eliminate all of the programming errors that cause memory leaks. |
Singular-value decomposition Reduced SVDs Singular-value_decomposition > Reduced SVDs In applications it is quite unusual for the full SVD, including a full unitary decomposition of the null-space of the matrix, to be required. Instead, it is often sufficient (as well as faster, and more economical for storage) to compute a reduced version of the SVD. The following can be distinguished for an m×n matrix M of rank r: |
Kinetic priority queue Summary Kinetic_priority_queue A Kinetic Priority Queue is an abstract kinetic data structure. It is a variant of a priority queue designed to maintain the maximum (or minimum) priority element (key-value pair) when the priority of every element is changing as a continuous function of time. Kinetic priority queues have been used as components of several kinetic data structures, as well as to solve some important non-kinetic problems such as the k-set problem and the connected red blue segments intersection problem. |
ULTRA (machine translation system) Summary ULTRA_(machine_translation_system) ULTRA is a machine translation system created for five languages (Japanese, Chinese, Spanish, English, and German) in the Computing Research Laboratory in 1991. ULTRA (Universal Language Translator), is a machine translation system developed at the Computing Research Laboratory, which can translate between five languages (Japanese, Chinese, Spanish, English and German). It uses Artificial intelligence as well as linguistic and logic programming methods. The main goal of the system is to be robust, to cover general language and to be simple to use. |
Computer Go Minimax tree search Computer_Go > System design > Minimax tree search There are several techniques, which can greatly improve the performance of search trees in terms of both speed and memory. Pruning techniques such as alpha–beta pruning, Principal Variation Search, and MTD(f) can reduce the effective branching factor without loss of strength. In tactical areas such as life and death, Go is particularly amenable to caching techniques such as transposition tables. |
Ballistic eye wear Performance standards Ballistic_eye_wear > Performance standards There are three standards currently used to test the effectiveness of ballistic eyewear. These include a U.S. civilian standard (ANSI Z87.1 – 2010), a U.S. military standard (MIL-PRF-31013), and a European standard (EN 166, 169, 170 and 172). |
Log-structured File System (BSD) Design Log-structured_File_System_(BSD) > Design This is intended to avoid the penalty of cleaning full segments when I/O bandwidth is most needed.At a checkpoint (usually scheduled about once every 30 seconds), LFS writes the last known block locations of the inode map and the number of the current segment to a checkpoint region at a fixed place on disk. There are two such regions; LFS alternates between them each checkpoint. Once written, a checkpoint represents the last consistent snapshot of the file system. Recovery after a crash and normal mounting work the same way—the file system simply reconstructs its state from the last checkpoint and resumes logging from there. |
PCMCIA card Name PCMCIA_card > Name PCMCIA stands for Personal Computer Memory Card International Association, the group of companies that defined the standard. This acronym was difficult to say and remember, and was sometimes jokingly referred to as "People Can't Memorize Computer Industry Acronyms". To recognize increased scope beyond memory, and to aid in marketing, the association acquired the rights to the simpler term "PC Card" from IBM. This was the name of the standard from version 2 of the specification onwards. These cards were used for wireless networks, modems, and other functions in notebook PCs. |
Table shuffleboard Tables Table_shuffleboard > Tables This section continues all the way to the foul line. The foul line measures 6 feet from the end of the table. The center third of the table is unmarked. The line that separates the center third of the table and the beginning of the "1 point" section is called the "foul line" (a weight which does not pass the foul line closest to the player is removed from the table for the round). The table is surrounded by a gutter, or "alley"; pucks that accidentally fall, or are knocked, into a gutter are out of play for the rest of the round. |
Path planning algorithm A* algorithm Path_planning_algorithm > Algorithms > A* algorithm If there is a path of length x between the start and finish, and the minimum distance between a node and the finish is greater than x, that node need not be examined.A* uses this heuristic to improve on the behavior relative to Dijkstra's algorithm. When the heuristic evaluates to zero, A* is equivalent to Dijkstra's algorithm. As the heuristic estimate increases and gets closer to the true distance, A* continues to find optimal paths, but runs faster (by virtue of examining fewer nodes). |
Geometric sequence Elementary properties Geometrical_progression > Elementary properties Generally, to check whether a given sequence is geometric, one simply checks whether successive entries in the sequence all have the same ratio. The common ratio of a geometric sequence may be negative, resulting in an alternating sequence, with numbers alternating between positive and negative. For instance 1, −3, 9, −27, 81, −243, ...is a geometric sequence with common ratio −3. |
Equal channel angular extrusion Finite element method in the ECAE process Equal_channel_angular_extrusion > Finite element method in the ECAE process The behave during deformation and flow of the material, are analyzed by scientists and there are many articles on computer simulation, finite element method is one of the important approaches to understand the deformation occurring in the ECAE process. |
Microvia Microvia reliability Microvia > Microvia reliability Microvia reliability research has focused on experimental assessment of the reliability of single-level unfilled microvias, as well as finite element analysis on stress/strain distributions in single-level microvias and microvia fatigue life estimation. Microvia failures identified from the research include interfacial separation (separation between the base of the microvia and the target pad), barrel cracks, corner/knee cracks, and target pad cracks (also referred to as microvia pull out). These failures result from the thermomechanical stresses caused by coefficient of thermal expansion (CTE) mismatch, in the PCB thickness direction, between the metallization in a microvia structure and the dielectric materials surrounding the metal. |
Object diagram Object diagram example Object_diagram > Object diagram topics > Object diagram example The topmost instance, an anonymous instance specification, has FibonacciFunction as its classifier, and may have an instance name, a role, and slots, but these are not shown here. The diagram also includes three named links, shown as lines. Links are instances of an association. |
Stack automaton Informal description Pushdown_automata > Informal description In each step, it chooses a transition by indexing a table by input symbol, current state, and the symbol at the top of the stack. A pushdown automaton can also manipulate the stack, as part of performing a transition. The manipulation can be to push a particular symbol to the top of the stack, or to pop off the top of the stack. |
Plane group First examples of groups 632_symmetry > First examples of groups The simplest wallpaper group, Group p1, applies when there is no symmetry other than the fact that a pattern repeats over regular intervals in two dimensions, as shown in the section on p1 below. The following examples are patterns with more forms of symmetry: Examples A and B have the same wallpaper group; it is called p4m in the IUCr notation and *442 in the orbifold notation. Example C has a different wallpaper group, called p4g or 4*2 . The fact that A and B have the same wallpaper group means that they have the same symmetries, regardless of details of the designs, whereas C has a different set of symmetries despite any superficial similarities. |
Bell nozzle Summary Bell_nozzle In fact, there are some non-axial components to the momentum. In terms of a momentum vector, there is an angle between the axis of the rocket engine and the gas flow. As a result, the thrust is lowered by varying amounts. |
Forking lemma Intuition Forking_lemma > Statement of the lemma > Intuition The idea here is to think of A as running two times in related executions, where the process "forks" at a certain point, when some but not all of the input has been examined. In the alternate version, the remaining inputs are re-generated but are generated in the normal way. The point at which the process forks may be something we only want to decide later, possibly based on the behavior of A the first time around: this is why the lemma statement chooses the branching point (J) based on the output of A. The requirement that hJ ≠ h'J is a technical one required by many uses of the lemma. (Note that since both hJ and h'J are chosen randomly from H, then if h is large, as is usually the case, the probability of the two values not being distinct is extremely small.) |
Time arrow Psychological/perceptual arrow of time Time_arrow > Arrows > Psychological/perceptual arrow of time The other side of the psychological passage of time is in the realm of volition and action. We plan and often execute actions intended to affect the course of events in the future. From the Rubaiyat: — Omar Khayyam (translation by Edward Fitzgerald). In June 2022, researchers reported in Physical Review Letters finding that salamanders were demonstrating counter-intuitive responses to the arrow of time in how their eyes perceived different stimuli. |
DNS root server Root server addresses Root_nameserver > Root server addresses There are 13 logical root name servers specified, with logical names in the form letter.root-servers.net, where letter ranges from a to m. The choice of thirteen name servers was made because of limitations in the original DNS specification, which specifies a maximum packet size of 512 bytes when using the User Datagram Protocol (UDP). Technically however, fourteen name servers fit into an IPv4 packet. The addition of IPv6 addresses for the root name servers requires more than 512 bytes, which is facilitated by the EDNS0 extension to the DNS standard.This does not mean that there are only 13 physical servers; each operator uses redundant computer equipment to provide reliable service even if failure of hardware or software occurs. |
Nucleoporin 37 Function Nucleoporin_37 > Function Transport of macromolecules between the cytoplasm and nucleus occurs through nuclear pore complexes (NPCs) embedded in the nuclear envelope. NPCs are composed of subcomplexes, and NUP37 is part of one such subcomplex, Nup107-160. |
Glossary of electrical and electronics engineering A Glossary_of_electrical_and_electronics_engineering > A amorphous metal transformer A power transformer where the metallic core is made of metals cooled so quickly that they do not form a crystal structure; such transformers can reduce some kinds of energy loss. ampacity The current carrying capacity of a conductor, in the context of electric power wiring. ampere The SI unit of electrical current. |
Job (computing) History Job_(computing) > History The term "job" has a traditional meaning as "piece of work", from Middle English "jobbe of work", and is used as such in manufacturing, in the phrase "job production", meaning "custom production", where it is contrasted with batch production (many items at once, one step at a time) and flow production (many items at once, all steps at the same time, by item). Note that these distinctions have become blurred in computing, where the oxymoronic term "batch job" is found, and used either for a one-off job or for a round of "batch processing" (same processing step applied to many items at once, originally punch cards). In this sense of "job", a programmable computer performs "jobs", as each one can be different from the last. The term "job" is also common in operations research, predating its use in computing, in such uses as job shop scheduling (see, for example Baker & Dzielinski (1960) and references thereof from throughout the 1950s, including several "System Research Department Reports" from IBM Research Center). |
Solar notebook Summary Solar_notebook The following is a list of products powered by sunlight, either directly or through electricity generated by solar panels. Solar air conditioning Solar balloon Solar charger Solar backpack Solar cell phone charger Strawberry Tree Solar chimney Solar-powered waste compacting bin Solar cooker Solar dryer Solar-powered fan Solar furnace Solar inverter Solar keyboard Solar lamp Solar pond Solar road stud Solar street light Solar traffic light Solar Tuki Solar-powered flashlight Solar notebook Solar-powered calculator Solar-powered desalination unit Solar-powered pump Solar PV Junction boxSolar-powered fountain Solar-powered radio Solar-powered refrigerator Solar-powered Stirling engine Solar-powered watch Solar-pumped laser Solar roadway Solar Spark Lighter Solar still Solar tree Solar vehicle Solar balloon Solar boat Tûranor PlanetSolar Solar bus Solar car Stella (solar vehicles) Solar golf cart Solar panels on spacecraft Solar sail Solar thermal rocket |
Axiomatic theory Example: The Peano axiomatization of natural numbers Axiomatic_theory > Axiomatic method > Example: The Peano axiomatization of natural numbers The mathematical system of natural numbers 0, 1, 2, 3, 4, ... is based on an axiomatic system first devised by the mathematician Giuseppe Peano in 1889. He chose the axioms, in the language of a single unary function symbol S (short for "successor"), for the set of natural numbers to be: There is a natural number 0. Every natural number a has a successor, denoted by Sa. There is no natural number whose successor is 0. Distinct natural numbers have distinct successors: if a ≠ b, then Sa ≠ Sb. If a property is possessed by 0 and also by the successor of every natural number it is possessed by, then it is possessed by all natural numbers ("Induction axiom"). |
Scientific proof Principles of inference Scientific_proof > Principles of inference In Bayesian inference, beliefs are expressed as percentages indicating one's confidence in them. One starts from an initial probability (a prior), and then updates that probability using Bayes' theorem after observing evidence. As a result, two independent observers of the same event will rationally arrive at different conclusions if their priors (previous observations that are also relevant to the conclusion) differ. The importance of background beliefs in the determination of what observations are evidence can be illustrated using deductive reasoning, such as syllogisms. If either of the propositions is not accepted as true, the conclusion will not be accepted either. |
Intake momentum drag Causes Intake_momentum_drag > Causes Intake momentum drag is caused by the consequence of the speed of the air entering the engine increasing, but where the exit speed of the air from the engine remains constant. The outcome therefore is that the amount by which the engine increases air velocity, ostensibly by way of the compression process, is reduced. A repercussion of this causes a slight reduction in the thrust of a jet engine. |
CRISPR gene editing Prime editing CRISPR_gene_editing > Applications > By technique > Prime editing The new guide, called a pegRNA, contains an RNA template for a new DNA sequence to be added to the genome at the target location. That requires a second protein, attached to Cas9: a reverse transcriptase enzyme, which can make a new DNA strand from the RNA template and insert it at the nicked site. |
Transition metal dinitrogen complex Bridging, end-on Transition_metal_dinitrogen_complex > Bonding modes > Bridging, end-on N2 also serves as a bridging ligand with "end-on" bonding to two metal centers, as illustrated by {2(μ-N2)}4+. These complexes are also called multinuclear dinitrogen complexes. In contrast to their mononuclear counterpart, they can be prepared for both early and late transition metals.In 2006, a study of iron-dinitrogen complexes by Holland and coworkers showed that the N–N bond is significantly weakened upon complexation with iron atoms with a low coordination number. The complex involved bidentate chelating ligands attached to the iron atoms in the Fe–N–N–Fe core, in which N2 acts as a bridging ligand between two iron atoms. |
Root of unity modulo n Finding an n with a primitive kth root of unity modulo n Root_of_unity_modulo_n > Primitive roots of unity > Finding an n with a primitive kth root of unity modulo n A simple way to find such an n is to check for primitive kth roots with respect to the moduli in the arithmetic progression k + 1 , 2 k + 1 , 3 k + 1 , … {\displaystyle k+1,2k+1,3k+1,\dots } All of these moduli are coprime to k and thus k is a unit. According to Dirichlet's theorem on arithmetic progressions there are infinitely many primes in the progression, and for a prime p {\displaystyle p} , it holds λ ( p ) = p − 1 {\displaystyle \lambda (p)=p-1} . Thus if m k + 1 {\displaystyle mk+1} is prime, then λ ( m k + 1 ) = m k {\displaystyle \lambda (mk+1)=mk} , and thus there are primitive kth roots of unity. But the test for primes is too strong, and there may be other appropriate moduli. |
Chemotherapy Treatment strategies Chemotherapy > Treatment strategies : 55–59 It is also given for cancers with a high risk of micrometastatic disease. : 42 Adjuvant chemotherapy is given after a local treatment (radiotherapy or surgery). It can be used when there is little evidence of cancer present, but there is risk of recurrence. |
Pentetic acid Coordination properties Diethylene_triamine_pentaacetic_acid > Coordination properties As a chelating agent, DTPA wraps around a metal ion by forming up to eight bonds. Its complexes can also have an extra water molecule that coordinates the metal ion. Transition metals, however, usually form less than eight coordination bonds. So, after forming a complex with a metal, DTPA still has the ability to bind to other reagents, as is shown by its derivative pendetide. For example, in its complex with copper(II), DTPA binds in a hexadentate manner utilizing the three amine centres and three of the five carboxylates. |
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